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Schmidt M, Hou X, Mai H, Zhou G, Melzer RR, Zhang X, Liu Y. Unveiling the ventral morphology of a rare early Cambrian great appendage arthropod from the Chengjiang biota of China. BMC Biol 2024; 22:96. [PMID: 38679748 PMCID: PMC11057168 DOI: 10.1186/s12915-024-01889-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 04/16/2024] [Indexed: 05/01/2024] Open
Abstract
BACKGROUND The early Cambrian arthropod clade Megacheira, also referred to as great appendage arthropods, comprised a group of diminutive and elongated predators during the early Palaeozoic era, around 518 million years ago. In addition to those identified in the mid-Cambrian Burgess Shale biota, numerous species are documented in the renowned 518-million-year-old Chengjiang biota of South China. Notably, one species, Tanglangia longicaudata, has remained inadequately understood due to limited available material and technological constraints. In this study, we, for the first time, examined eight fossil specimens (six individuals) utilizing state-of-the-art μCT and computer-based 3D rendering techniques to unveil the hitherto hidden ventral and appendicular morphology of this species. RESULTS We have identified a set of slender endopodites gradually narrowing distally, along with a leaf-shaped exopodite adorned with fringed setae along its margins, and a small putative exite attached to the basipodite. Our techniques have further revealed the presence of four pairs of biramous appendages in the head, aligning with the recently reported six-segmented head in other early euarthropods. Additionally, we have discerned two peduncle elements for the great appendage. These findings underscore that, despite the morphological diversity observed in early euarthropods, there exists similarity in appendicular morphology across various groups. In addition, we critically examine the existing literature on this taxon, disentangling previous mislabelings, mentions, descriptions, and, most importantly, illustrations. CONCLUSIONS The μCT-based investigation of fossil material of Tanglangia longicaudata, a distinctive early Cambrian euarthropod from the renowned Chengjiang biota, enhances our comprehensive understanding of the evolutionary morphology of the Megacheira. Its overall morphological features, including large cup-shaped eyes, raptorial great appendages, and a remarkably elongated telson, suggest its potential ecological role as a crepuscular predator and adept swimmer in turbid waters.
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Affiliation(s)
- Michel Schmidt
- Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Münchhausenstrasse 21, 81247, Munich, Germany
| | - Xianguang Hou
- Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
| | - Huijuan Mai
- Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
| | - Guixian Zhou
- Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
| | - Roland R Melzer
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Münchhausenstrasse 21, 81247, Munich, Germany
- Faculty of Biology, Biocenter, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, Planegg-Martinsried, 82152, Germany
- GeoBio-Center, Ludwig-Maximilians-University Munich, Luisenstrasse 37, Munich, 80333, Germany
| | - Xilin Zhang
- Chengjiang Fossil Museum of the Management Committee of the Chengjiang World Heritage Fossil Site, Yuxi, People's Republic of China
| | - Yu Liu
- Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China.
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China.
- Chengjiang Fossil Museum of the Management Committee of the Chengjiang World Heritage Fossil Site, Yuxi, People's Republic of China.
- Southwest United Graduate School, Kunming, 650091, People's Republic of China.
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Skoracki M, Unsoeld M, Kosicki JZ, Melzer RR, Friedrich S, Sikora B. Enigmatic host-mite relationships: Unraveling the distribution of quill mites on Birds-of-Paradise. Int J Parasitol 2024:S0020-7519(24)00059-6. [PMID: 38575051 DOI: 10.1016/j.ijpara.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/15/2024] [Accepted: 03/28/2024] [Indexed: 04/06/2024]
Abstract
Mites of the family Syringophilidae (Acariformes: Prostigmata: Cheyletoidea) are permanent and obligatory parasites of birds. This study presents an analysis of mite material collected from 22 avian species belonging to the family Paradisaeidae (Passeriformes), revealing the presence of four mite species belonging to four genera: Syringophiloidus attenboroughi n. sp., Peristerophila regiusi n. comb., Picobia frankei, and Gunabopicobia garylarsoni. In the present work, the genus Neoperisterophila is synonymized with the genus Peristerophila. While the genera Syringophiloidus and Picobia were expectedly found on paradisaeid birds, given their prevalence in passerines, the presence of Peristerophila and Gunabopicobia was intriguing, suggesting potential host-switching events. The specificity of these mites varies, with some showing occurrence on hosts of closely related genera and others infesting phylogenetically distant hosts. Notably, the distribution of specific mite species on the Birds-of-Paradise appears to be influenced by both long coevolutionary histories and incidental contacts between often unrelated or intergeneric hybrid species of paradisaeid birds. Furthermore, our research of 104 specimens from 22 Birds-of-Paradise species shows generally low infestation rates across the studied species, suggesting a nuanced interaction between these mites and their avian hosts. Additionally, our network analysis provides a deeper understanding of these host-parasite interactions, revealing a high level of specialization and complexity in these ecological relationships.
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Affiliation(s)
- Maciej Skoracki
- Department of Animal Morphology, Faculty of Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
| | - Markus Unsoeld
- SNSB-Bavarian State Collection of Zoology, Sektion Ornithology, Münchhausenstr. 21, 81247 Munich, Germany
| | - Jakub Z Kosicki
- Department of Avian Biology and Ecology, Faculty of Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Roland R Melzer
- SNSB-Bavarian State Collection of Zoology, Sektion Arthropoda Varia, Münchhausenstr. 21, 81247 Munich, Germany; Ludwig-Maximilians-Universität München, Faculty of Biology, 82152 Planegg-Martinsried, Germany; GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Str. 10, 80333 Munich, Germany
| | - Stefan Friedrich
- SNSB-Bavarian State Collection of Zoology, Sektion Arthropoda Varia, Münchhausenstr. 21, 81247 Munich, Germany; Ludwig-Maximilians-Universität München, Faculty of Biology, 82152 Planegg-Martinsried, Germany
| | - Bozena Sikora
- Department of Animal Morphology, Faculty of Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
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Schmidt M, Martin I, Melzer RR. Just a matter of size? Evaluating allometry and intersexual heterometry in Pagurus bernhardus using ratios and indices (Decapoda, Anomura). Integr Zool 2023. [PMID: 38123465 DOI: 10.1111/1749-4877.12794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Heterochely denotes the presence of dissimilarly sized chelipeds on opposite sides of the body, a prevalent occurrence in diverse crustaceans. Conversely, heterometry pertains to the quantifiable disparities in size between these chelipeds. Both chelipeds hold pivotal roles in activities such as foraging, mating, and defense. Consequently, individuals of both genders in heterochelic species exhibit this morphological pattern. Previous studies have identified sexual dimorphism in cheliped size, with males displaying larger major chelipeds compared to females, albeit solely relying on propodus length as a size proxy and focusing solely on the major cheliped. In our study, we meticulously examined 190 specimens of the common European hermit crab Pagurus bernhardus from two collections. We sought to elucidate allometric relationships and assess whether heterometry exhibited sex-based differences when adjusting for body size by using ratios. Our findings revealed that male chelipeds displayed hyperallometric growth relative to females, and all three calculated heterometry indices exhibited significant disparities between the sexes. Consequently, male specimens exhibited larger major and minor chelipeds, even when theoretically matched for body size with females. This phenomenon may be attributed, among other factors, to male-male contests. Should indirect mate selection favor males with larger chelipeds in proportion to their body size, this dynamic could potentiate sexual selection in their favor.
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Affiliation(s)
- Michel Schmidt
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany
- Faculty of Biology, Biocenter, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Munich, Germany
| | | | - Roland R Melzer
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany
- Faculty of Biology, Biocenter, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Munich, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, Munich, Germany
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Bicknell RDC, Schmidt M, Rahman IA, Edgecombe GD, Gutarra S, Daley AC, Melzer RR, Wroe S, Paterson JR. Raptorial appendages of the Cambrian apex predator Anomalocaris canadensis are built for soft prey and speed. Proc Biol Sci 2023; 290:20230638. [PMID: 37403497 DOI: 10.1098/rspb.2023.0638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2023] Open
Abstract
The stem-group euarthropod Anomalocaris canadensis is one of the largest Cambrian animals and is often considered the quintessential apex predator of its time. This radiodont is commonly interpreted as a demersal hunter, responsible for inflicting injuries seen in benthic trilobites. However, controversy surrounds the ability of A. canadensis to use its spinose frontal appendages to masticate or even manipulate biomineralized prey. Here, we apply a new integrative computational approach, combining three-dimensional digital modelling, kinematics, finite-element analysis (FEA) and computational fluid dynamics (CFD) to rigorously analyse an A. canadensis feeding appendage and test its morphofunctional limits. These models corroborate a raptorial function, but expose inconsistencies with a capacity for durophagy. In particular, FEA results show that certain parts of the appendage would have experienced high degrees of plastic deformation, especially at the endites, the points of impact with prey. The CFD results demonstrate that outstretched appendages produced low drag and hence represented the optimal orientation for speed, permitting acceleration bursts to capture prey. These data, when combined with evidence regarding the functional morphology of its oral cone, eyes, body flaps and tail fan, suggest that A. canadensis was an agile nektonic predator that fed on soft-bodied animals swimming in a well-lit water column above the benthos. The lifestyle of A. canadensis and that of other radiodonts, including plausible durophages, suggests that niche partitioning across this clade influenced the dynamics of Cambrian food webs, impacting on a diverse array of organisms at different sizes, tiers and trophic levels.
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Affiliation(s)
- Russell D C Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale 2351, Australia
- Division of Paleontology, American Museum of Natural History, New York, NY 10027, USA
| | - Michel Schmidt
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China
| | - Imran A Rahman
- The Natural History Museum, Cromwell Road, London SW7 5BD, UK
- Oxford University Museum of Natural History, Oxford OX1 3PW, UK
| | | | - Susana Gutarra
- The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Allison C Daley
- Institute of Earth Sciences, University of Lausanne, Lausanne CH-1015, Switzerland
| | - Roland R Melzer
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany
- Faculty of Biology, Biocenter, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Stephen Wroe
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale 2351, Australia
- Function, Evolution and Anatomy Research Lab, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia
| | - John R Paterson
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale 2351, Australia
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Sikora B, Unsoeld M, Melzer RR, Friedrich S, Skoracki M. First Records of Picobiine Mites Associated with Birds-of-Paradise: Can Interspecific Sexual Behaviour of Hosts Play a Role in the Distribution of Quill Mite Parasites? Animals (Basel) 2023; 13:ani13091509. [PMID: 37174545 PMCID: PMC10177229 DOI: 10.3390/ani13091509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
While birds-of-paradise (Passeriformes: Paradisaeidae) are a well-known group of birds, our understanding of their parasites is still limited. This study reports on parasitic quill mites of the subfamily Picobiinae (Acariformes: Syringophilidae), which have never before been recorded on this group of birds. The mite specimens presented in this paper were collected from birds-of-paradise that had been captured in Papua New Guinea and Indonesia in the years 1910-1911 and are now deposited in the Bavarian State Collection of Zoology, Munich, Germany. Two syringophilid species are described as new to science: (i) Picobia frankei sp. n. from the magnificent riflebird Lophorina magnifica, the glossy-mantled manucode Manucodia ater, and the crinkle-collared manucode Manucodia chalybatus, and (ii) Gunabopicobia garylarsoni sp. n. from the twelve-wired bird-of-paradise Seleucidis melanoleucus and the lesser bird-of-paradise Paradisaea minor. We hypothesise that the presence of both picobiine species on phylogenetically unrelated paradisaeids may be caused by the sexual behaviour of these birds, where interspecific copulations may play a role in the switching of parasites between non-closely related host species.
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Affiliation(s)
- Bozena Sikora
- Department of Animal Morphology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Markus Unsoeld
- SNSB-Bavarian State Collection of Zoology, Sektion Ornithology, Münchhausenstr. 21, 81247 Munich, Germany
| | - Roland R Melzer
- SNSB-Bavarian State Collection of Zoology, Sektion Arthropoda Varia, Münchhausenstr. 21, 81247 Munich, Germany
- Faculty of Biology, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Str. 10, 80333 Munich, Germany
| | - Stefan Friedrich
- SNSB-Bavarian State Collection of Zoology, Sektion Arthropoda Varia, Münchhausenstr. 21, 81247 Munich, Germany
- Faculty of Biology, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany
| | - Maciej Skoracki
- Department of Animal Morphology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
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Wolf L, Melzer RR, Lehmann T. Rediscovery after 25 years – first photographic documentation and DNA barcoding of the deep-sea pycnogonid species Ascorhynchus hippos Turpaeva, 1994 (Chelicerata, Pycnogonida, Ascorhynchidae) from the Kuril-Kamchatka Trench. ZOOSYST EVOL 2022. [DOI: 10.3897/zse.98.84864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The female specimen of Ascorhynchus hippos Turpaeva, 1994 was collected in 2015 during the Russian-German deep-sea expedition SokhoBio (Sea of Okhotsk Biodiversity Studies) at the abyssal western slope of the Kuril-Kamchatka Trench at a depth of 4469 m using a camera-epibenthic sledge. It is the first record of this species since the discovery of one female holotype and one male paratype in 1990. Ascorhynchus hippos is easily distinguishable from its congeners by the two prominent tubercles above the chelifore insertions, the absence of the eye tubercle and eyes, and the tubercles on the mid-dorsal trunk segments and the lateral processes. Here we present the first photographic documentation of all three known specimens of A. hippos and the COI barcode of the new specimen is also provided.
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Schmidt M, Hou X, Zhai D, Mai H, Belojević J, Chen X, Melzer RR, Ortega-Hernández J, Liu Y. Before trilobite legs: Pygmaclypeatus daziensis reconsidered and the ancestral appendicular organization of Cambrian artiopods. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210030. [PMID: 35125003 PMCID: PMC8819370 DOI: 10.1098/rstb.2021.0030] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Cambrian Stage 3 Chengjiang biota in South China is one of the most influential Konservat-Lagerstätten worldwide thanks to the fossilization of diverse non-biomineralizing organisms through pyritization. Despite their contributions to understanding the evolution of early animals, several Chengjiang species remain poorly known owing to their scarcity and/or incomplete preservation. Here, we use micro-computed tomography to reveal in detail the ventral appendage organization of the enigmatic non-trilobite artiopod Pygmaclypeatus daziensis-one of the rarest euarthropods in Chengjiang-and explore its functional ecology and broader evolutionary significance. Pygmaclypeatus daziensis possesses a set of uniramous antennae and 14 pairs of post-antennal biramous appendages, the latter of which show an unexpectedly high degree of heteronomy based on the localized differentiation of the protopodite, endopodite and exopodite along with the antero-posterior body axis. The small body size (less than 2 cm), the presence of delicate spinose endites and well-developed exopodites with multiple paddle-shaped lamellae on the appendages of P. daziensis indicate a nekto-benthic mode of life and a scavenging/detritus feeding strategy. Pygmaclypeatus daziensis shows that appendage heteronomy is phylogenetically widespread within Artiopoda-the megadiverse clade that includes trilobites and their relatives with non-biomineralizing exoskeletons-and suggests that a single exopodite lobe with paddle-like lamellae is ancestral for this clade. This article is part of the theme issue 'The impact of Chinese palaeontology on evolutionary research'.
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Affiliation(s)
- Michel Schmidt
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China.,Bavarian State Collection of Zoology, Bavarian Natural History Collections, Münchhausenstrasse 21, 81247 München, Germany.,Department Biology II, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany
| | - Xianguang Hou
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China.,Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China
| | - Dayou Zhai
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China.,Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China
| | - Huijuan Mai
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China.,Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China
| | - Jelena Belojević
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Münchhausenstrasse 21, 81247 München, Germany
| | - Xiaohan Chen
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China.,Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China
| | - Roland R Melzer
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China.,Bavarian State Collection of Zoology, Bavarian Natural History Collections, Münchhausenstrasse 21, 81247 München, Germany.,Department Biology II, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität Munich, Luisenstrasse 37, 80333 München, Germany
| | - Javier Ortega-Hernández
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, 791 Cambridge, MA 02138, USA
| | - Yu Liu
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China.,Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, North Cuihu Road 2, Kunming 650091, People's Republic of China
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Schmidt M, Melzer RR, Plotnick RE, Bicknell RD. Spines and baskets in apex predatory sea scorpions uncover unique feeding strategies using 3D-kinematics. iScience 2022; 25:103662. [PMID: 35024591 PMCID: PMC8733173 DOI: 10.1016/j.isci.2021.103662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 11/21/2021] [Accepted: 12/16/2021] [Indexed: 11/28/2022] Open
Abstract
Megalograptidae and Mixopteridae with elongate, spinose prosomal appendages are unique early Palaeozoic sea scorpions (Eurypterida). These features were presumably used for hunting, an untested hypothesis. Here, we present 3D model-based kinematic range of motion (ROM) analyses of Megalograptus ohioensis and Mixopterus kiaeri and compare these to modern analogs. This comparison confirms that the eurypterid appendages were likely raptorial, used in grabbing and holding prey for consumption. The Megalograptus ohioensis model illustrates notable Appendage III flexibility, indicating hypertrophied spines on Appendage III may have held prey, while Appendage II likely ripped immobilized prey. Mixopterus kiaeri, conversely, constructed a capture basket with Appendage III, and impaled prey with Appendage II elongated spines. Thus, megalograptid and mixopterid frontalmost appendages constructed a double basket system prior to moving dismembered prey to the chelicerae. Such 3D kinematic modeling presents a more complete understanding of these peculiar euchelicerates and highlights their possible position within past ecosystems.
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Affiliation(s)
- Michel Schmidt
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany
- Department Biology II, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Roland R. Melzer
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany
- Department Biology II, Ludwig-Maximilians-Universität München, Munich, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Roy E. Plotnick
- Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Russell D.C. Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, Australia
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Bicknell RDC, Melzer RR, Schmidt M. Three-dimensional kinematics of euchelicerate limbs uncover functional specialization in eurypterid appendages. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab108] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Sea scorpions (Euchelicerata: Eurypterida) explored extreme limits of the aquatic euchelicerate body plan, such that the group contains the largest known marine euarthropods. Inferences on eurypterid life modes, in particular walking and eating, are commonly made by comparing the group with horseshoe crabs (Euchelicerata: Xiphosura). However, no models have been presented to test these hypotheses. Here, we reconstruct prosomal appendages of two exceptionally well-preserved eurypterids, Eurypterus tetragonophthalmus and Pentecopterus decorahensis, and model the flexure and extension of these appendages kinematically in three dimensions (3D). We compare these models with 3D kinematic models of Limulus polyphemus prosomal appendages. This comparison highlights that the examined eurypterid prosomal appendages could not have moved prey items effectively to the gnathal edges and would therefore not have emulated the motion of an L. polyphemus walking leg. It seems that these eurypterid appendages were used primarily to walk or grab prey, and other appendages would have moved prey for mastication. Such 3D kinematic modelling highlights how eurypterid appendage morphologies placed substantial limits on their function, suggesting a high degree of specialization, especially when compared with horseshoe crabs. Such three-dimensional kinematic modelling of these extinct groups therefore presents an innovative approach to understanding the position of these animals within their respective palaeoecosystems.
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Affiliation(s)
- Russell D C Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale,NSW 2351,Australia
| | - Roland R Melzer
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich,Germany
- Department Biology II, Ludwig-Maximilians-Universität München, Munich,Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, Munich,Germany
| | - Michel Schmidt
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich,Germany
- Department Biology II, Ludwig-Maximilians-Universität München, Munich,Germany
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10
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Schmidt M, Melzer RR, Bicknell RDC. Kinematics of whip spider pedipalps: a 3D comparative morpho-functional approach. Integr Zool 2021; 17:156-167. [PMID: 34532979 DOI: 10.1111/1749-4877.12591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/12/2021] [Accepted: 09/14/2021] [Indexed: 11/30/2022]
Abstract
Amblypygi are tropical and subtropical ambush predators that use elongated, raptorial pedipalps for different activities. Although pedipalp use in predation and courtship has been explored in videography in vivo analyses, kinematic ex vivo examination of these appendages has not been conducted. Here, we rectify this lack of data by using micro-CT scans to 3D-kinematically model the appendage morphology and the range of motion (ROM) of the joints for Damon medius and Heterophrynus elaphus. We illustrate the successful application of this technique to terrestrial euarthropods in determining the maximum ROM values for each pedipalp joint. We also note that, in life, these values would be lower due to motion restricting structures like tendons, arthrodial membranes, and muscles. We further compare our maximum values obtained here with data from video-based motion analyses. The ROM of each joint shows the greatest flexibility in the femur-tibia joint (140-150°), the lowest in the basitarsus-claw joint (35-40°). ROM in the tibia-basitarsus joint is markedly distinct (D. medius: 44°; H. elaphus: 105°). This disparity reflects how H. elaphus uses the joint in the capture basket, while D. medius uses the femur-tibia joint to form the capture basket. We further illustrate notable vertical motion of the H. elaphus pedipalp compared to D. medius. This difference reflects the retro-ventral trochanter apophysis of H. elaphus. Our study opens the possibility to further whip spider kinematic understanding. Examination of other taxa using this approach will result in a more comprehensive understanding of the ecological significance and ethological implications of this unique arachnid group.
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Affiliation(s)
- Michel Schmidt
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany.,Department Biology II, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Roland R Melzer
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany.,Department Biology II, Ludwig-Maximilians-Universität München, Munich, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Russell D C Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, Australia
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11
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Liu Y, Edgecombe GD, Schmidt M, Bond AD, Melzer RR, Zhai D, Mai H, Zhang M, Hou X. Exites in Cambrian arthropods and homology of arthropod limb branches. Nat Commun 2021; 12:4619. [PMID: 34330912 PMCID: PMC8324779 DOI: 10.1038/s41467-021-24918-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/14/2021] [Indexed: 11/28/2022] Open
Abstract
The last common ancestor of all living arthropods had biramous postantennal appendages, with an endopodite and exopodite branching off the limb base. Morphological evidence for homology of these rami between crustaceans and chelicerates has, however, been challenged by data from clonal composition and from knockout of leg patterning genes. Cambrian arthropod fossils have been cited as providing support for competing hypotheses about biramy but have shed little light on additional lateral outgrowths, known as exites. Here we draw on microtomographic imaging of the Cambrian great-appendage arthropod Leanchoilia to reveal a previously undetected exite at the base of most appendages, composed of overlapping lamellae. A morphologically similar, and we infer homologous, exite is documented in the same position in members of the trilobite-allied Artiopoda. This early Cambrian exite morphology supplements an emerging picture from gene expression that exites may have a deeper origin in arthropod phylogeny than has been appreciated.
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Affiliation(s)
- Yu Liu
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China
- MEC International Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China
| | - Gregory D Edgecombe
- MEC International Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China.
- Department of Earth Sciences, The Natural History Museum, London, UK.
| | - Michel Schmidt
- MEC International Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, München, Germany
- Department Biology II, Ludwig-Maximilians-Universität München, Planegg-Martinsried, München, Germany
| | - Andrew D Bond
- Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey, UK
| | - Roland R Melzer
- MEC International Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, München, Germany
- Department Biology II, Ludwig-Maximilians-Universität München, Planegg-Martinsried, München, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, München, Germany
| | - Dayou Zhai
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China
- MEC International Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China
| | - Huijuan Mai
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China
- MEC International Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China
| | - Maoyin Zhang
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China
- MEC International Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China
| | - Xianguang Hou
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China.
- MEC International Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China.
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12
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Schmidt M, Liu Y, Hou X, Haug JT, Haug C, Mai H, Melzer RR. Intraspecific variation in the Cambrian: new observations on the morphology of the Chengjiang euarthropod Sinoburius lunaris. BMC Ecol Evol 2021; 21:127. [PMID: 34154529 PMCID: PMC8215796 DOI: 10.1186/s12862-021-01854-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 05/23/2021] [Indexed: 11/22/2022] Open
Abstract
Background The Chengjiang biota from southwest China (518-million-years old, early Cambrian) has yielded nearly 300 species, of which more than 80 species represent early chelicerates, crustaceans and relatives. The application of µCT-techniques combined with 3D software (e.g., Drishti), has been shown to be a powerful tool in revealing and analyzing 3D features of the Chengjiang euarthropods. In order to address several open questions that remained from previous studies on the morphology of the xandarellid euarthropod Sinoburius lunaris, we reinvestigated the µCT data with Amira to obtain a different approach of visualization and to generate new volume-rendered models. Furthermore, we used Blender to design 3D models showing aspects of intraspecific variation. Results New findings are: (1) antennulae consist of additional proximal articles that have not been detected before; (2) compared to other appendages, the second post-antennular appendage has a unique shape, and its endopod is comprised of only five articles (instead of seven); (3) the pygidium bears four pairs of appendages which are observed in all specimens. On the other hand, differences between specimens also have been detected. These include the presence/absence of diplotergites resulting in different numbers of post-antennular appendages and tergites and different distances between the tip of the hypostome and the anterior margin of the head shield. Conclusions Those new observations reveal intraspecific variation among Chengjiang euarthropods not observed before and encourage considerations about possible sexual dimorphic pairs or ontogenetic stages. Sinoburius lunaris is a variable species with respect to its morphological characters, cautioning that taxon-specific variabilities need to be considered when exploring new species. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01854-1.
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Affiliation(s)
- Michel Schmidt
- Faculty of Biology, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany. .,MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China. .,Bavarian State Collection of Zoology, Bavarian Natural History Collections, Münchhausenstr. 21, 81247, Munich, Germany.
| | - Yu Liu
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China. .,Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China.
| | - Xianguang Hou
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China.,Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
| | - Joachim T Haug
- Faculty of Biology, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Str. 10, 80333, Munich, Germany
| | - Carolin Haug
- Faculty of Biology, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Str. 10, 80333, Munich, Germany
| | - Huijan Mai
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China.,Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China
| | - Roland R Melzer
- Faculty of Biology, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany.,MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China.,Bavarian State Collection of Zoology, Bavarian Natural History Collections, Münchhausenstr. 21, 81247, Munich, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Str. 10, 80333, Munich, Germany
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13
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Lehmann T, Melzer RR. Outsourcing a visual neuropil - The central visual system of the median eyes of Galeodes granti Pocock, 1903 (Arachnida: Solifugae). Arthropod Struct Dev 2021; 60:101024. [PMID: 33383276 DOI: 10.1016/j.asd.2020.101024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 06/12/2023]
Abstract
Only a few studies have examined the central visual system of Solifugae until now. To get new insights suitable for phylogenetic analysis we studied the R-cell (or retinula cell) projections and visual neuropils of Galeodes granti using various methods. G. granti possesses large median eyes and rudimentary lateral eyes. In this study, only the R-cells and neuropils of the median eyes were successfully stained. The R-cells terminate in two distinct visual neuropils. The first neuropil is located externally to the protocerebrum directly below the retina, the second neuropil lies in the cell body rind of the protocerebrum, and immediately adjacent is the arcuate body. This layout of the median eye visual system differs from Arachnopulmonata (Scorpiones + Tetrapulmonata). However, there are several similarities with Opiliones. In both, (1) the R-cells are connected to a first and second visual neuropil and not to any other region of the brain, (2) the first neuropil is not embedded in the cell body rind of the protocerebrum, it is rather external to the protocerebrum, (3) the second visual neuropil is embedded in the cell body rind, and (4) the second neuropil abuts the arcuate body. These findings may provide important new characters for the discussion on arachnid phylogeny.
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Affiliation(s)
- Tobias Lehmann
- Bavarian State Collection of Zoology - SNSB, Münchhausenstraße 21, 81247, Munich, Germany.
| | - Roland R Melzer
- Bavarian State Collection of Zoology - SNSB, Münchhausenstraße 21, 81247, Munich, Germany; Ludwig-Maximilians-Universität München, Department Biologie II, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany; GeoBioCenter(LMU), Richard -Wagner-Str. 10, 80333 Munich, Germany
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14
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Schmidt M, Liu Y, Zhai D, Hou X, Melzer RR. Moving legs: A workflow on how to generate a flexible endopod of the 518 million-year-old Chengjiang arthropod Ercaicunia multinodosa using 3D-kinematics (Cambrian, China). Microsc Res Tech 2020; 84:695-704. [PMID: 33155750 DOI: 10.1002/jemt.23628] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 01/22/2023]
Abstract
Understanding the functional morphology and mobility of appendages of fossil animals is important for exploring ecological traits such as feeding and locomotion. Previous work on fossils from the 518 million-year-old Chengjiang biota of China was based mainly on two-dimensional information captured from the surface of the specimens. Only recently, μCT techniques started to reveal almost the entire, though flattened and compressed, three-dimensionally preserved morphologies of the arthropods from Chengjiang. This allows more accurate work on reconstructing the possible movement of certain structures such as the appendages. Here, we present a workflow on how to reconstruct the mobility of a limb of the early Chengjiang arthropod Ercaicunia multinodosa from the famous Chinese fossil site. Based on μCT scans of the fossil, we rendered surface models of the 13th-15th right endopods using the 3D visualization and 3D-rendering software Amira. The 3D objects then were postprocessed (Collapse Hierarchy, Unify Normals) in SAP 3D Visual Enterprise Author before being imported into the 3D animation program Autodesk Maya 2020. Using the add-on tool X_ROMM in Maya, we illustrate step-by-step on how to make the articles of the limbs swing-in toward each other. Eventually, we propose several possible limb movements of E. multinodosa, which helps to understand how this early arthropod could have moved its endopods.
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Affiliation(s)
- Michel Schmidt
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany.,MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China.,Department Biology II, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Yu Liu
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China.,Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China
| | - Dayou Zhai
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China.,Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China
| | - Xianguang Hou
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China.,Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China
| | - Roland R Melzer
- Bavarian State Collection of Zoology, Bavarian Natural History Collections, Munich, Germany.,MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China.,Department Biology II, Ludwig-Maximilians-Universität München, Munich, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität München, Munich, Germany
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15
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Dömel JS, Macher TH, Dietz L, Duncan S, Mayer C, Rozenberg A, Wolcott K, Leese F, Melzer RR. Combining morphological and genomic evidence to resolve species diversity and study speciation processes of the Pallenopsis patagonica (Pycnogonida) species complex. Front Zool 2019; 16:36. [PMID: 31516540 PMCID: PMC6728986 DOI: 10.1186/s12983-019-0316-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/06/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pallenopsis patagonica (Hoek, 1881) is a morphologically and genetically variable sea spider species whose taxonomic classification is challenging. Currently, it is considered as a species complex including several genetic lineages, many of which have not been formally described as species. Members of this species complex occur on the Patagonian and Antarctic continental shelves as well as around sub-Antarctic islands. These habitats have been strongly influenced by historical large-scale glaciations and previous studies suggested that communities were limited to very few refugia during glacial maxima. Therefore, allopatric speciation in these independent refugia is regarded as a common mechanism leading to high biodiversity of marine benthic taxa in the high-latitude Southern Hemisphere. However, other mechanisms such as ecological speciation have rarely been considered or tested. Therefore, we conducted an integrative morphological and genetic study on the P. patagonica species complex to i) resolve species diversity using a target hybrid enrichment approach to obtain multiple genomic markers, ii) find morphological characters and analyze morphometric measurements to distinguish species, and iii) investigate the speciation processes that led to multiple lineages within the species complex. RESULTS Phylogenomic results support most of the previously reported lineages within the P. patagonica species complex and morphological data show that several lineages are distinct species with diagnostic characters. Two lineages are proposed as new species, P. aulaeturcarum sp. nov. Dömel & Melzer, 2019 and P. obstaculumsuperavit sp. nov. Dömel, 2019, respectively. However, not all lineages could be distinguished morphologically and thus likely represent cryptic species that can only be identified with genetic tools. Further, morphometric data of 135 measurements showed a high amount of variability within and between species without clear support of adaptive divergence in sympatry. CONCLUSIONS We generated an unprecedented molecular data set for members of the P. patagonica sea spider species complex with a target hybrid enrichment approach, which we combined with extensive morphological and morphometric analyses to investigate the taxonomy, phylogeny and biogeography of this group. The extensive data set enabled us to delineate species boundaries, on the basis of which we formally described two new species. No consistent evidence for positive selection was found, rendering speciation in allopatric glacial refugia as the most likely model of speciation.
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Affiliation(s)
- Jana S. Dömel
- Aquatic Ecosystem Research, Faculty of Biology, University of Duisburg-Essen, Universitaetsstr. 5, 45141 Essen, Germany
| | - Till-Hendrik Macher
- Aquatic Ecosystem Research, Faculty of Biology, University of Duisburg-Essen, Universitaetsstr. 5, 45141 Essen, Germany
| | - Lars Dietz
- Zoological Research Museum Alexander Koenig, Statistical Phylogenetics and Phylogenomics, Adenauerallee 160, 53113 Bonn, Germany
| | - Sabrina Duncan
- Bavarian State Collection of Zoology – SNSB, Muenchhausenstr. 21, 81247 Munich, Germany
| | - Christoph Mayer
- Zoological Research Museum Alexander Koenig, Statistical Phylogenetics and Phylogenomics, Adenauerallee 160, 53113 Bonn, Germany
| | - Andrey Rozenberg
- Faculty of Biology, Technion – Israel Institute of Technology, 3200003 Haifa, Israel
| | - Katherine Wolcott
- Bavarian State Collection of Zoology – SNSB, Muenchhausenstr. 21, 81247 Munich, Germany
| | - Florian Leese
- Aquatic Ecosystem Research, Faculty of Biology, University of Duisburg-Essen, Universitaetsstr. 5, 45141 Essen, Germany
- Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitaetsstr. 2, 45141 Essen, Germany
| | - Roland R. Melzer
- Bavarian State Collection of Zoology – SNSB, Muenchhausenstr. 21, 81247 Munich, Germany
- Department Biologie II, LMU Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
- GeoBioCenter, LMU Munich, Richard-Wagner-Str. 10, 80333 Munich, Germany
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16
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Schwaha T, Ruthensteiner B, Melzer RR, Asami T, Páll‐Gergely B. Three phyla—Two type specimens—One shell: History of a snail shell revealed by modern imaging technology. J ZOOL SYST EVOL RES 2019. [DOI: 10.1111/jzs.12293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Thomas Schwaha
- Department of Integrative Zoology University of Vienna Vienna Austria
| | | | | | - Takahiro Asami
- Department of Biology Shinshu University Matsumoto Japan
| | - Barna Páll‐Gergely
- Plant Protection Institute, Centre for Agricultural Research Hungarian Academy of Sciences Budapest Hungary
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17
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Lehmann T, Melzer RR. The visual system of Thelyphonida (whip scorpions): Support for Arachnopulmonata. Arthropod Struct Dev 2019; 51:23-31. [PMID: 31176004 DOI: 10.1016/j.asd.2019.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 06/09/2023]
Abstract
Only a few studies have examined the central visual system of Thelyphonida (whip scorpions) until now. To obtain new insights suitable for phylogenetic analysis we studied the axonal trajectories and neuropil architecture of the central visual systems of two whip scorpion species (Mastigoproctus giganteus and Typopeltis dalyi) with different neuroanatomical techniques (Cobalt fills, Wigglesworth stains, and μCT). The central visual system of whip scorpion comprises one pair of median eyes and one pair of lateral eye triplets. The R-cells (or retinula cells) of both eye types each terminate in a first and a second visual neuropil. Furthermore, a few R-cell fibres from the median eyes leave the second median eye visual neuropil and terminate in the second and the first lateral eye neuropil. This means R-cell terminals from the lateral eyes and the median eyes overlap here. Additionally, the arcuate body and mushroom bodies are described. A detailed comparison of our findings with previously studied chelicerate central visual systems seems to support a monophyly of Arachnopulmonata, i.e. a clade comprising Tetrapulmonata (Thelyphonida, Schizomida, Amblypygi, and Araneae) and Scorpions. Furthermore, the architecture of the central visual systems hints at a close evolutionary relationship of Arachnopulmonata and Xiphosura.
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Affiliation(s)
- Tobias Lehmann
- Bavarian State Collection of Zoology - SNSB, Münchhausenstraße 21, 81247, Munich, Germany.
| | - Roland R Melzer
- Bavarian State Collection of Zoology - SNSB, Münchhausenstraße 21, 81247, Munich, Germany; Ludwig-Maximilians-Universität München, Department Biologie II, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany; GeoBioCenter(LMU), Richard -Wagner-Str. 10, 80333, Munich, Germany
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18
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Abstract
BACKGROUND Only a few studies have examined the visual systems of Amblypygi (whip spiders) until now. To get new insights suitable for phylogenetic analysis we studied the axonal trajectories and neuropil architecture of the visual systems of several whip spider species (Heterophrynus elaphus, Damon medius, Phrynus pseudoparvulus, and P. marginemaculatus) with different neuroanatomical techniques. The R-cell axon terminals were identified with Cobalt fills. To describe the morphology of the visual neuropils and of the protocerebrum generally we used Wigglesworth stains and μCT. RESULTS The visual system of whip spiders comprises one pair of median and three pairs of lateral eyes. The R-cells of both eye types terminate each in a first and a second visual neuropil. Furthermore, a few R-cell fibres from the median eyes leave the second median eye visual neuropil and terminate in the second lateral eye neuropil. This means R-cell terminals from the lateral eyes and the median eyes overlap. Additionally, the arcuate body and the mushroom bodies are described. CONCLUSIONS A detailed comparison of our findings with previously studied chelicerate visual systems (i.e., Xiphosura, Scorpiones, Pseudoscorpiones, Opiliones, and Araneae) seem to support the idea of close evolutionary relationships between Xiphosura, Scorpiones, and Amblypygi.
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Affiliation(s)
- Tobias Lehmann
- Bavarian State Collection of Zoology – SNSB, Münchhausenstraße 21, 81247 Munich, Germany
- Ludwig-Maximilians-Universität München, Department Biologie II, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany
| | - Roland R. Melzer
- Bavarian State Collection of Zoology – SNSB, Münchhausenstraße 21, 81247 Munich, Germany
- Ludwig-Maximilians-Universität München, Department Biologie II, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany
- GeoBioCenter LMU, Richard -Wagner-Str. 10, 80333 Munich, Germany
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19
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Dreyer N, Yusa Y, Gale A, Melzer RR, Yamato S, Høeg JT. In the footsteps of Darwin: dwarf male attachment sites in scalpellid barnacles (Crustacea: Cirripedia: Thoracica) – implications for phylogeny and the evolution of sexual systems. Zool J Linn Soc 2018. [DOI: 10.1093/zoolinnean/zly018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- N Dreyer
- Natural History Museum of Denmark, Zoological Museum, Section for Biosystematics, University of Copenhagen, Universitetsparken, Copenhagen East, Denmark
| | - Y Yusa
- Nara Women’s University, Kitauoya-nishi, Nara, Japan
| | - A Gale
- School of Earth and Environmental Sciences, University of Portsmouth, Burnaby Building Burnaby Road, Portsmouth, UK
| | - R R Melzer
- Bavarian State Collection of Zoology, Münchhausenstr. 21, Munich, Germany
- Geobio Center LMU, Richard-Wagner-Str. 10, Munich, Germany
| | - S Yamato
- Seto Marine Biological Laboratory, Kyoto University, Shirahama, Wakayama, Japan
| | - J T Høeg
- Marine Biological Section, Department of Biology, University of Copenhagen, Universitetsparken, Copenhagen East, Denmark
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20
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Dietz L, Dömel JS, Leese F, Lehmann T, Melzer RR. Feeding ecology in sea spiders (Arthropoda: Pycnogonida): what do we know? Front Zool 2018; 15:7. [PMID: 29568315 PMCID: PMC5856303 DOI: 10.1186/s12983-018-0250-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/24/2018] [Indexed: 11/10/2022] Open
Abstract
Sea spiders (Pycnogonida) are a widespread and phylogenetically important group of marine arthropods. However, their biology remains understudied, and detailed information about their feeding ecology is difficult to find. Observations on pycnogonid feeding are scattered in the literature, often in older sources written in various languages, and have never been comprehensively summarized. Here we provide an overview of all information on feeding in pycnogonids that we have been able to find and review what is known on feeding specializations and preferences in the various pycnogonid taxa. We deduce general findings where possible and outline future steps necessary to gain a better understanding of the feeding ecology of one of the world's most bizarre animal taxa.
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Affiliation(s)
- Lars Dietz
- Zoological Research Museum Alexander Koenig, Statistical Phylogenetics and Phylogenomics, Adenauerallee 160, D-53113 Bonn, Germany.,2Faculty of Mathematics and Natural Sciences, University of Bonn, D-53012 Bonn, Germany
| | - Jana S Dömel
- 3Aquatic Ecosystem Research, Faculty of Biology, University Duisburg-Essen, Universitätsstr. 5, D-45141 Essen, Germany
| | - Florian Leese
- 3Aquatic Ecosystem Research, Faculty of Biology, University Duisburg-Essen, Universitätsstr. 5, D-45141 Essen, Germany
| | - Tobias Lehmann
- Bavarian State Collection of Zoology - SNSB, Münchhausenstraße 21, 81247 Munich, Germany.,5Department Biologie II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
| | - Roland R Melzer
- Bavarian State Collection of Zoology - SNSB, Münchhausenstraße 21, 81247 Munich, Germany.,5Department Biologie II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany.,6GeoBioCenter LMU, Richard -Wagner-Str. 10, 80333 Munich, Germany
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Lehmann T, Melzer RR. A tiny visual system — retinula axons and visual neuropils of Neobisium carcinoides (Hermann, 1804) (Chelicerata, Arachnida, Pseudoscorpiones). ZOOL ANZ 2018. [DOI: 10.1016/j.jcz.2017.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Schulz-Mirbach T, Olbinado M, Rack A, Mittone A, Bravin A, Melzer RR, Ladich F, Heß M. In-situ visualization of sound-induced otolith motion using hard X-ray phase contrast imaging. Sci Rep 2018; 8:3121. [PMID: 29449570 PMCID: PMC5814409 DOI: 10.1038/s41598-018-21367-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/30/2018] [Indexed: 11/23/2022] Open
Abstract
Regarding the basics of ear structure-function relationships in fish, the actual motion of the solid otolith relative to the underlying sensory epithelium has rarely been investigated. Otolith motion has been characterized based on a few experimental studies and on approaches using mathematical modeling, which have yielded partially conflicting results. Those studies either predicted a simple back-and-forth motion of the otolith or a shape-dependent, more complex motion. Our study was designed to develop and test a new set-up to generate experimental data on fish otolith motion in-situ. Investigating the basic parameters of otolith motion requires an approach with high spatial and temporal resolution. We therefore used hard X-ray phase contrast imaging (XPCI). We compared two anatomically well-studied cichlid species, Steatocranus tinanti and Etroplus maculatus, which, among other features, differ in the 3D shape of their otoliths. In a water-filled tank, we presented a pure tone of 200 Hz to 1) isolated otoliths embedded in agarose serving as a simple model or 2) to a fish (otoliths in-situ). Our new set-up successfully visualized the motion of otoliths in-situ and therefore paves the way for future studies evaluating the principles of otolith motion.
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Affiliation(s)
- Tanja Schulz-Mirbach
- Ludwig-Maximilians-University Munich, Department Biology II, Zoology, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany
| | - Margie Olbinado
- European Synchrotron Radiation Facility (ESRF, ID19), 71 Avenue des Martyrs, 38000, Grenoble, France
| | - Alexander Rack
- European Synchrotron Radiation Facility (ESRF, ID19), 71 Avenue des Martyrs, 38000, Grenoble, France
| | - Alberto Mittone
- European Synchrotron Radiation Facility (ESRF, ID17), 71 Avenue des Martyrs, 38000, Grenoble, France
| | - Alberto Bravin
- European Synchrotron Radiation Facility (ESRF, ID17), 71 Avenue des Martyrs, 38000, Grenoble, France
| | - Roland R Melzer
- Bavarian State Collection of Zoology (ZSM), Münchhausenstraße 21, 81247, Munich, Germany
| | - Friedrich Ladich
- University of Vienna, Department of Behavioural Biology, Althanstraße 14, 1090, Vienna, Austria.
| | - Martin Heß
- Ludwig-Maximilians-University Munich, Department Biology II, Zoology, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany
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Affiliation(s)
- Tobias Lehmann
- Bavarian State Collection of Zoology - SNSB; Munich Germany
- Department Biologie II; Ludwig-Maximilians-Universität München; Planegg-Martinsried Germany
| | - Martin Heß
- Department Biologie II; Ludwig-Maximilians-Universität München; Planegg-Martinsried Germany
| | - Roland R. Melzer
- Bavarian State Collection of Zoology - SNSB; Munich Germany
- Department Biologie II; Ludwig-Maximilians-Universität München; Planegg-Martinsried Germany
- GeoBioCenter; Munich Germany
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Dömel JS, Melzer RR, Harder AM, Mahon AR, Leese F. Nuclear and Mitochondrial Gene Data Support Recent Radiation within the Sea Spider Species Complex Pallenopsis patagonica. Front Ecol Evol 2017. [DOI: 10.3389/fevo.2016.00139] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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Hübner J, Wagner P, Lehmann T, Melzer RR. Testing species delimitation with larval morphology: scanning electron microscopy analysis of protonymphon larvae of two closely related sea spiders, Pallenopsis patagonica (Hoek) and Pallenopsis yepayekae Weis. INVERTEBR SYST 2017. [DOI: 10.1071/is16050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We used scanning electron microscopy (SEM) to establish species-specific sets of characters for protonymphon larvae of two representatives of the ‘patagonica’ species group of Pallenopsis, P. patagonica and P. yepayekae. The larvae of both species are ‘typical’ protonymphon larvae sensu Bain (2003). Despite the close relationship of the two species, we observed numerous features that allow for differential diagnosis, e.g. general habitus, the number, arrangement and branching type of setules, the armature of the movable and immovable chelifore fingers, and the shape of the dactylus and setules of appendages II and III. SEM is particularly suitable for visualising these features. Our results further support the idea that protonymphon larvae can be identified to species level when adequate imaging techniques are used, as is also the case for larvae of other arthropods. Moreover, the status of the two studied species of Pallenopsis is fully supported by protonymphon larval morphology.
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Lehmann T, Lodde-Bensch E, Melzer RR, Metz M. The visual system of harvestmen (Opiliones, Arachnida, Chelicerata) - a re-examination. Front Zool 2016; 13:50. [PMID: 27891163 PMCID: PMC5112708 DOI: 10.1186/s12983-016-0182-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/02/2016] [Indexed: 01/31/2023] Open
Abstract
Background The visual systems in chelicerates are poorly understood, even though they show strong variation in eye and visual neuropil architecture, thus may provide valuable insights for the understanding of chelicerate phylogeny and eye evolution. Comparable morphological characters are desperately sought for reconstructions of the phylogeny of Chelicerata, especially with respect to Arachnida. So far, reliable data exist only for Pycnogonida, Xiphosura, Scorpiones, and Araneae. The few earlier studies of the organisation of the visual system in harvestmen are contradictory concerning the number, morphology, and position of the visual neuropils. Results We undertook a descriptive and comparative analysis of the neuroanatomy of the visual system in several phalangid harvestmen species. Various traditional and modern methods were used that allow comparisons with previous results (cobalt fills, DiI/DiO labelling, osmium ethyl gallate procedure, and TEM). The R-cells (photoreceptor and arhabdomeric cells) in the eyes of Opiliones are linked to a first and a second visual neuropil. The first visual neuropil receives input from all R-cell axons, in the second only few R-cells terminate in the distal part. Hence, the second visual neuropil is subdivided in a part with direct R-cell input and a part without. The arcuate body is located in a subsequent position with direct contact to the second visual neuropil. Conclusions This re-examination comes to conclusions different from those of all previous studies. The visual system of phalangid Opiliones occupies an intermediate position between Pycnogonida, Xiphosura, and Scorpiones on the one side, and Araneae on the other side. The projection of the R-cells is similar to that in the former grouping, the general neuropil arrangement to that in the latter taxon. However, more research on the visual systems in other chelicerate orders is needed in order to draw inferences on phylogeny or eye evolution.
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Affiliation(s)
- Tobias Lehmann
- Bavarian State Collection of Zoology, SNSB, Münchhausenstraße 21, 81247 Munich, Germany ; Department Biologie II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
| | - Eva Lodde-Bensch
- Bavarian State Collection of Zoology, SNSB, Münchhausenstraße 21, 81247 Munich, Germany
| | - Roland R Melzer
- Bavarian State Collection of Zoology, SNSB, Münchhausenstraße 21, 81247 Munich, Germany ; Department Biologie II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany ; GeoBioCenter, LMU, Richard -Wagner-Str. 10, 80333 Munich, Germany
| | - Martina Metz
- Bavarian State Collection of Zoology, SNSB, Münchhausenstraße 21, 81247 Munich, Germany
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Dietz L, Arango CP, Dömel JS, Halanych KM, Harder AM, Held C, Mahon AR, Mayer C, Melzer RR, Rouse GW, Weis A, Wilson NG, Leese F. Regional differentiation and extensive hybridization between mitochondrial clades of the Southern Ocean giant sea spider Colossendeis megalonyx. R Soc Open Sci 2015; 2:140424. [PMID: 26587257 PMCID: PMC4632570 DOI: 10.1098/rsos.140424] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 06/29/2015] [Indexed: 05/13/2023]
Abstract
Assessing the enormous diversity of Southern Ocean benthic species and their evolutionary histories is a central task in the era of global climate change. Based on mitochondrial markers, it was recently suggested that the circumpolar giant sea spider Colossendeis megalonyx comprises a complex of at least six cryptic species with mostly small and non-overlapping distribution ranges. Here, we expand the sampling to include over 500 mitochondrial COI sequences of specimens from around the Antarctic. Using multiple species delimitation approaches, the number of distinct mitochondrial OTUs increased from six to 15-20 with our larger dataset. In contrast to earlier studies, many of these clades show almost circumpolar distributions. Additionally, analysis of the nuclear internal transcribed spacer region for a subset of these specimens showed incongruence between nuclear and mitochondrial results. These mito-nuclear discordances suggest that several of the divergent mitochondrial lineages can hybridize and should not be interpreted as cryptic species. Our results suggest survival of C. megalonyx during Pleistocene glaciations in multiple refugia, some of them probably located on the Antarctic shelf, and emphasize the importance of multi-gene datasets to detect the presence of cryptic species, rather than their inference based on mitochondrial data alone.
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Affiliation(s)
- Lars Dietz
- Faculty of Biology and Biotechnology, Department of Animal Ecology, Evolution and Biodiversity, Ruhr University Bochum, Universitaetsstrasse 150, Bochum 44801, Germany
| | - Claudia P. Arango
- Natural Environments Program, Queensland Museum, PO Box 3300, South Brisbane, Queensland 4101, Australia
| | - Jana S. Dömel
- Faculty of Biology and Biotechnology, Department of Animal Ecology, Evolution and Biodiversity, Ruhr University Bochum, Universitaetsstrasse 150, Bochum 44801, Germany
| | | | - Avril M. Harder
- Department of Biology, Institute for Great Lakes Research, Central Michigan University, Mount Pleasant, MI, USA
| | - Christoph Held
- Alfred Wegener Institute, Helmholtz Center for Marine and Polar Biology, Am Alten Hafen 26, Bremerhaven 25768, Germany
| | - Andrew R. Mahon
- Department of Biology, Institute for Great Lakes Research, Central Michigan University, Mount Pleasant, MI, USA
| | - Christoph Mayer
- Zoological Research Museum Alexander Koenig, Adenauerallee 160, Bonn 53113, Germany
| | - Roland R. Melzer
- Bavarian State Collection of Zoology—SNSB, Münchhausenstraße 21, Munich 81247, Germany
- Department Biology II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, Planegg-Martinsried 82152, Germany
- GeoBio-Center, Richard-Wagner-Straße 10, Munich 80333, Germany
| | - Greg W. Rouse
- Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla 92093-0202, CA, USA
| | - Andrea Weis
- Bavarian State Collection of Zoology—SNSB, Münchhausenstraße 21, Munich 81247, Germany
| | - Nerida G. Wilson
- Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla 92093-0202, CA, USA
- Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia
| | - Florian Leese
- Faculty of Biology and Biotechnology, Department of Animal Ecology, Evolution and Biodiversity, Ruhr University Bochum, Universitaetsstrasse 150, Bochum 44801, Germany
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Lehmann T, Heß M, Wanner G, Melzer RR. Dissecting a neuron network: FIB-SEM-based 3D-reconstruction of the visual neuropils in the sea spider Achelia langi (Dohrn, 1881) (Pycnogonida). BMC Biol 2014; 12:59. [PMID: 25285383 PMCID: PMC4159573 DOI: 10.1186/s12915-014-0059-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/21/2014] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND The research field of connectomics arose just recently with the development of new three-dimensional-electron microscopy (EM) techniques and increasing computing power. So far, only a few model species (for example, mouse, the nematode Caenorhabditis elegans, and the fruit fly Drosophila melanogaster) have been studied using this approach. Here, we present a first attempt to expand this circle to include pycnogonids, which hold a key position for the understanding of arthropod evolution. The visual neuropils in Achelia langi are studied using a focused ion beam-scanning electron microscope (FIB-SEM) crossbeam-workstation, and a three-dimensional serial reconstruction of the connectome is presented. RESULTS The two eyes of each hemisphere of the sea spider's eye tubercle are connected to a first and a second visual neuropil. The first visual neuropil is subdivided in two hemineuropils, each responsible for one eye and stratified into three layers. Six different neuron types postsynaptic to the retinula (R-cells) axons are characterized by their morphology: five types of descending unipolar neurons and one type of ascending neurons. These cell types are also identified by Golgi impregnations. Mapping of all identifiable chemical synapses indicates that the descending unipolar neurons are postsynaptic to the R-cells and, hence, are second-order neurons. The ascending neurons are predominantly presynaptic and sometimes postsynaptic to the R-cells and may play a feedback role. CONCLUSIONS Comparing these results with the compound eye visual system of crustaceans and insects - the only arthropod visual system studied so far in such detail - we found striking similarities in the morphology and synaptic organization of the different neuron types. Hence, the visual system of pycnogonids shows features of both chelicerate median and mandibulate lateral eyes.
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Affiliation(s)
- Tobias Lehmann
- />Bavarian State Collection of Zoology – SNSB, Münchhausenstraße 21, 81247 Munich, Germany
- />Department Biology II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
| | - Martin Heß
- />Department Biology II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
- />GeoBio-Center LMU, Richard-Wagner-Straße 10, 80333 Munich, Germany
| | - Gerhard Wanner
- />Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Straße 2-4, 82152 Planegg-Martinsried, Germany
| | - Roland R Melzer
- />Bavarian State Collection of Zoology – SNSB, Münchhausenstraße 21, 81247 Munich, Germany
- />Department Biology II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
- />GeoBio-Center LMU, Richard-Wagner-Straße 10, 80333 Munich, Germany
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Batel A, Melzer RR, Anger K, Geiselbrecht H. Heterochrony in mandible development of larval shrimp (Decapoda: Caridea)--a comparative morphological SEM study of two carideans. J Morphol 2014; 275:1258-72. [PMID: 24888760 DOI: 10.1002/jmor.20299] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 04/14/2014] [Accepted: 05/01/2014] [Indexed: 11/06/2022]
Abstract
Mandible development in the larval stages I-V of two palaemonid shrimp species, Palaemon elegans and Macrobrachium amazonicum, was analyzed using scanning electron microscopy, light microscopy, and confocal laser scanning microscopy. In contrast to the zoea I of P. elegans, first-stage larvae of M. amazonicum are nonfeeding. At hatching, the morphology of the mandibles is fully expressed in P. elegans, while it appears underdeveloped in M. amazonicum, presenting only small precursors of typical caridean features. In successive zoeal stages, both species show similar developmental changes, but the mandibular characters of the larvae in M. amazonicum were delayed compared to the equivalent stages in P. elegans, especially in the development of submarginal setae and mandible size. In conclusion, our results indicate heterochrony (postdisplacement) of mandible development in M. amazonicum compared to that in P. elegans, which is related to initial lack of mandible functionality or planktivorous feeding at hatching, respectively. This conclusion is supported by comparison with other palaemonid zoeae exhibiting different feeding modes. Our data suggest that an evolutionary ground pattern of mandible morphology is present even in species with nonfeeding first-stage larvae.
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Affiliation(s)
- Annika Batel
- Faculty of Biology, Technical University of Munich, 85350, Weihenstephan, Freising, Germany
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Geiselbrecht H, Melzer RR. Fine structure and ecdysis of mandibular sensilla associated with the lacinia mobilis in Neomysis integer (Leach, 1814) (Crustacea, Malacostraca, Peracarida). Arthropod Struct Dev 2014; 43:221-230. [PMID: 24508944 DOI: 10.1016/j.asd.2014.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 06/03/2023]
Abstract
The external and internal structures of adult Neomysis integer mandibles were studied using light and electron microscopy with special reference to the lacinia mobilis, a highly specialized appendage on the gnathal edge of many crustaceans. The right and left lacinia mobilis are equipped with ciliary primary sensory cells revealing that both laciniae are also mechanosensory organs in addition to their mechanical function during mastication. A detailed character analyses indicated that the right lacinia is probably a highly derived sensory seta, whereas two alternative interpretations are considered for the left lacinia; it could be a sensillar appendage equipped with two mechanosensory units, or it could be a movable appendage of the incisor process containing two sensilla deprived of external appendages. The ecdysis of the lacinia mobilis corresponds very well to type I sensillar ecdysis, suggesting classification as a sensillar appendage. These features support a possible homology of the right lacinia mobilis in Peracarida and Decapoda, tracing them to an origin as a member of the setal row. Whether the left lacinia mobilis is a sensillum or an appendage with sensilla cannot be resolved presently.
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Affiliation(s)
- Hannes Geiselbrecht
- Zoologische Staatssammlung München, Münchhausenstraße 21, 81247 München, Germany; Department Biologie II, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.
| | - Roland R Melzer
- Zoologische Staatssammlung München, Münchhausenstraße 21, 81247 München, Germany; Department Biologie II, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany; GeoBioCenter(LMU), Richard-Wagner-Str. 10, 80333 München, Germany
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Weis A, Meyer R, Dietz L, Dömel JS, Leese F, Melzer RR. Pallenopsis patagonica(Hoek, 1881) - a species complex revealed by morphology and DNA barcoding, with description of a new species ofPallenopsis Wilson, 1881. Zool J Linn Soc 2014. [DOI: 10.1111/zoj.12097] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrea Weis
- Zoologische Staatssammlung München; Münchhausenstraße 21 81247 München Germany
| | - Roland Meyer
- Zoologische Staatssammlung München; Münchhausenstraße 21 81247 München Germany
| | - Lars Dietz
- Ruhr-Universität Bochum, Evolutionsökologie und Biodiversität der Tiere; Universitätsstraße 150 D-44801 Bochum Germany
| | - Jana S. Dömel
- Ruhr-Universität Bochum, Evolutionsökologie und Biodiversität der Tiere; Universitätsstraße 150 D-44801 Bochum Germany
| | - Florian Leese
- Ruhr-Universität Bochum, Evolutionsökologie und Biodiversität der Tiere; Universitätsstraße 150 D-44801 Bochum Germany
| | - Roland R. Melzer
- Zoologische Staatssammlung München; Münchhausenstraße 21 81247 München Germany
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Geiselbrecht H, Melzer RR. Nervous systems in 3D: a comparison of Caridean, anomuran, and brachyuran zoea-I (Decapoda). J Exp Zool B Mol Dev Evol 2013; 320:511-24. [PMID: 24038813 DOI: 10.1002/jez.b.22528] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 07/22/2013] [Accepted: 07/31/2013] [Indexed: 11/06/2022]
Abstract
Using serial semi-thin sections and digital 3D-reconstructions we studied the nervous systems of zoea-I larvae in three decapod species, Hippolyte inermis (Leach, 1815), Porcellana platycheles (Pennant, 1777), and Pachygrapsus marmoratus (Fabricius, 1787). These taxa represent three decapod lineages, that is, Caridea, Anomura, and Brachyura, each characterized by specific zoea-I morphology. Special attention was paid to development of ganglia, neuropil composition, and segmental nerves. In all zoeae studied, the overall elements, for example, the segmental ganglia, their neuropils and most of the nerves of the adult decapod nervous system are present. Ongoing differentiation processes are observable as well, most obvious in segments with well-developed limbs the ganglia are in a more advanced stage of differentiation and more voluminous compared to segments with only limb buds or without externally visible limb anlagen. Intra- and interspecific comparisons indicate that neuromere differentiation thus deviates from a simple anterior-posterior gradient as, for example, posterior thoracic neuromeres are less developed than those of the pleon. In addition, the differences in the progress of the development of ganglia between the studied taxa can best be attributed to heterochronic mechanisms. Taxon and stage-specific morphologies indicate that neuronal architecture reflects both, morphogenesis to the adult stage and specific larval adaptions, and provides sets of characters relevant to understanding the corresponding phylogeny.
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Affiliation(s)
- Hannes Geiselbrecht
- Zoologische Staatssammlung München, München, Germany; Department Biology I, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
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Meyer R, Weis A, Melzer RR. Decapoda of southern Chile: DNA barcoding and integrative taxonomy with focus on the generaAcanthocyclusandEurypodius. SYST BIODIVERS 2013. [DOI: 10.1080/14772000.2013.833143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Lehmann T, Melzer RR. Looking like Limulus? - Retinula axons and visual neuropils of the median and lateral eyes of scorpions. Front Zool 2013; 10:40. [PMID: 23842208 PMCID: PMC3717128 DOI: 10.1186/1742-9994-10-40] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 07/01/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Despite ongoing interest in the neurophysiology of visual systems in scorpions, aspects of their neuroanatomy have received little attention. Lately sets of neuroanatomical characters have contributed important arguments to the discussion of arthropod ground patterns and phylogeny. In various attempts to reconstruct phylogeny (from morphological, morphological + molecular, or molecular data) scorpions were placed either as basalmost Arachnida, or within Arachnida with changing sister-group relationships, or grouped with the extinct Eurypterida and Xiphosura inside the Merostomata. Thus, the position of scorpions is a key to understanding chelicerate evolution. To shed more light on this, the present study for the first time combines various techniques (Cobalt fills, DiI / DiO labelling, osmium-ethyl gallate procedure, and AMIRA 3D-reconstruction) to explore central projections and visual neuropils of median and lateral eyes in Euscorpius italicus (Herbst, 1800) and E. hadzii Di Caporiacco, 1950. RESULTS Scorpion median eye retinula cells are linked to a first and a second visual neuropil, while some fibres additionally connect the median eyes with the arcuate body. The lateral eye retinula cells are linked to a first and a second visual neuropil as well, with the second neuropil being partly shared by projections from both eyes. CONCLUSIONS Comparing these results to previous studies on the visual systems of scorpions and other chelicerates, we found striking similarities to the innervation pattern in Limulus polyphemus for both median and lateral eyes. This supports from a visual system point of view at least a phylogenetically basal position of Scorpiones in Arachnida, or even a close relationship to Xiphosura. In addition, we propose a ground pattern for the central projections of chelicerate median eyes.
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Affiliation(s)
- Tobias Lehmann
- SNSB – Bavarian State Collection of Zoology, Münchhausenstraße 21, Munich 81247, Germany
- Department Biology II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, Planegg-Martinsried 82152, Germany
| | - Roland R Melzer
- SNSB – Bavarian State Collection of Zoology, Münchhausenstraße 21, Munich 81247, Germany
- Department Biology II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, Planegg-Martinsried 82152, Germany
- GeoBio-Center at LMU, Richard-Wagner-Str. 10, 80333, Munich, Germany
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Geiselbrecht H, Melzer RR. How do mandibles sense? The sensory apparatus of larval mandibles in Palaemon elegans Rathke, 1837 (Decapoda, Palaemonidae). Arthropod Struct Dev 2013; 42:1-16. [PMID: 23010507 DOI: 10.1016/j.asd.2012.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/05/2012] [Accepted: 09/05/2012] [Indexed: 06/01/2023]
Abstract
The mandibles of decapod zoea-I larvae are robustly built masticating mouthparts equipped with several processes and spines. Superficial examination of these sturdy, inflexible structures can suggest that they are lacking sensory receptors. However, detailed TEM analysis of their ultrastructure revealed up to 11 sensillar cell clusters on the gnathal edges of the mandibles of the zoea-I in Palaemon elegans Rathke, 1837. Based on ultrastructural criteria we distinguish 7 types of sensilla: mechanoreceptors, chemoreceptors and mechano- and chemoreceptors. One sensory unit located at the base of the 'lacinia mobilis' exhibits the typical features of a crustacean mechanosensitive sensillum with an external seta and corresponding ultrastructure. Another unit shows features indicating bimodal contact chemosensitivity. A third one is similar to known olfactory chemoreceptors. Using the concept of modality-specific structures we analyse the structure and functional morphology of each sensillum, and give a comprehensive overview of the sensory abilities of zoea mandibles. We take a closer look at the ultrastructure of the 'lacinia mobilis', providing further features to trace its evolutionary history in Decapoda, and thus contributing to a better understanding of malacostracan phylogeny.
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Weis A, Melzer RR. How did sea spiders recolonize the Chilean fjords after glaciation? DNA barcoding of Pycnogonida, with remarks on phylogeography of Achelia assimilis(Haswell, 1885). SYST BIODIVERS 2012. [DOI: 10.1080/14772000.2012.716462] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Melzer RR. Animal Eyes 2nd edn. Land, M. F. and Nilsson, D.-E. (2012). Oxford University Press, Oxford, 271 pp, Hardback GBP 65.00, Paperback GBP 32,50. ISBN 978-0-19-958114-6. ACTA ZOOL-STOCKHOLM 2012. [DOI: 10.1111/j.1463-6395.2012.00570.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Roland R Melzer
- Sektion Arthropoda varia, Zoologische Staatssammlung; Bavarian State Collection of Zoology; Münchhausenstr. 21; D-81247; München; Germany
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Lehmann T, Hess M, Melzer RR. Wiring a periscope--ocelli, retinula axons, visual neuropils and the ancestrality of sea spiders. PLoS One 2012; 7:e30474. [PMID: 22279594 PMCID: PMC3261207 DOI: 10.1371/journal.pone.0030474] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 12/19/2011] [Indexed: 11/19/2022] Open
Abstract
The Pycnogonida or sea spiders are cryptic, eight-legged arthropods with four median ocelli in a 'periscope' or eye tubercle. In older attempts at reconstructing phylogeny they were Arthropoda incertae sedis, but recent molecular trees placed them as the sister group either to all other euchelicerates or even to all euarthropods. Thus, pycnogonids are among the oldest extant arthropods and hold a key position for the understanding of arthropod evolution. This has stimulated studies of new sets of characters conductive to cladistic analyses, e.g. of the chelifores and of the hox gene expression pattern. In contrast knowledge of the architecture of the visual system is cursory. A few studies have analysed the ocelli and the uncommon "pseudoinverted" retinula cells. Moreover, analyses of visual neuropils are still at the stage of Hanström's early comprehensive works. We have therefore used various techniques to analyse the visual fibre pathways and the structure of their interrelated neuropils in several species. We found that pycnogonid ocelli are innervated to first and second visual neuropils in close vicinity to an unpaired midline neuropil, i.e. possibly the arcuate body, in a way very similar to ancestral euarthropods like Euperipatoides rowelli (Onychophora) and Limulus polyphemus (Xiphosura). This supports the ancestrality of pycnogonids and sheds light on what eyes in the pycnogonid ground plan might have 'looked' like. Recently it was suggested that arthropod eyes originated from simple ocelli similar to larval eyes. Hence, pycnogonid eyes would be one of the early offshoots among the wealth of more sophisticated arthropod eyes.
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Spelda J, Reip HS, Oliveira-Biener U, Melzer RR. Barcoding Fauna Bavarica: Myriapoda - a contribution to DNA sequence-based identifications of centipedes and millipedes (Chilopoda, Diplopoda). Zookeys 2011:123-39. [PMID: 22303099 PMCID: PMC3253575 DOI: 10.3897/zookeys.156.2176] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 12/02/2011] [Indexed: 12/03/2022] Open
Abstract
We give a first account of our ongoing barcoding activities on Bavarian myriapods in the framework of the Barcoding Fauna Bavarica project and IBOL, the International Barcode of Life. Having analyzed 126 taxa (including 122 species) belonging to all major German chilopod and diplopod lineages, often using four or more specimens each, at the moment our species stock includes 82% of the diplopods and 65% of the chilopods found in Bavaria, southern Germany. The partial COI sequences allow correct identification of more than 95% of the current set of Bavarian species. Moreover, most of the myriapod orders and families appear as distinct clades in neighbour-joining trees, although the phylogenetic relationships between them are not always depicted correctly. We give examples of (1) high interspecific sequence variability among closely related species; (2) low interspecific variability in some chordeumatidan genera, indicating that recent speciations cannot be resolved with certainty using COI DNA barcodes; (3) high intraspecific variation in some genera, suggesting the existence of cryptic lineages; and (4) the possible polyphyly of some taxa, i.e. the chordeumatidan genus Ochogona. This shows that, in addition to species identification, our data may be useful in various ways in the context of species delimitations, taxonomic revisions and analyses of ongoing speciation processes.
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Affiliation(s)
- Jörg Spelda
- Section Arthropoda Varia, Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany
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Oliveira-Biener U, Melzer RR, Miller MA. Pilumnus Leach (Decapoda:Pilumnidae Samouelle) from Mediterranean and adjacent Atlantic waters: a COI analysis. INVERTEBR SYST 2010. [DOI: 10.1071/is09051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A molecular taxonomy is presented based on 544 base pair sequences of the mitochondrial COI gene (Palumbi segment) from 141 bristle crabs of the genus Pilumnus from the Mediterranean Sea and adjacent Atlantic Ocean, plus outgroups. The sample includes all currently valid autochthonous Mediterranean species. Six well-supported COI lineages were detected, three of which exclusively comprise representatives of Pilumnus inermis, P. spinifer and P. villosissimus, respectively. On the other hand, crabs that would be attributed to P. hirtellus according to current morphology-based taxonomy were distributed over three COI clades, two of which are interpreted as representing cryptic lineages. We compare our findings to previous analyses using sets of external morphological characters, and discuss the partial mismatch between the morphology- and gene-based classifications.
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Melzer RR. Persisting stemma neuropils inChaoborus crystallinus(Diptera: Chaoboridae): Development and evolution of a bipartite visual system. J Morphol 2009; 270:1524-30. [DOI: 10.1002/jmor.10779] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Lehmann T, Gailer JP, Melzer RR, Schwabe E. A scanning-electron microscopic study of Dickdellia labioflecta (Dell, 1990) (Gastropoda, Littorinoidea) on Colossendeis megalonyx megalonyx Fry and Hedgpeth, 1969 (Pycnogonida, Colossendeidae): a test for ectoparasitism. Polar Biol 2006. [DOI: 10.1007/s00300-006-0178-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hess M, Melzer RR, Eser R, Smola U. The structure of anchovy outer retinae (Engraulididae, Clupeiformes) — A comparative light- and electron-microscopic study using museum-stored material. J Morphol 2006; 267:1356-80. [PMID: 17051549 DOI: 10.1002/jmor.10482] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The outer retinal architecture of Engraulididae is uncommon among vertebrates. In some anchovies, e.g., Anchoa, two cone types are arranged alternating in long photoreceptor chains, i.e., polycones. The cones have radially oriented outer segment lamellae in close contact with a complex guanine tapetum, most probably subserving polarization contrast vision. To clarify the distribution of the aberrant polycone architecture within the Engraulididae and to provide indications about polycone evolution, the outer retina morphology of 16 clupeoid species was investigated by light and electron microscopy, predominantly using museum-stored material. The outgroup representatives of four clupeid subfamilies (Clupeonella cultriventris, Dorosoma cepedianum, Ethmalosa fimbriata, Pellonula leonensis) show a row pattern of double cones, partially with single cones at defined positions and a pigment epithelium with lobopodial protrusions containing melanin. The pristigasterid Ilisha africana has double rows of single cones lying between linear curtains of pigment epithelium processes filled with minute crystallites and melanin concentrated near their vitreal tips. Within the Engraulididae, two main architectures are found: Coilia nasus and Thryssa setirostris have linear multiple cones or polycones separated by long pigment epithelium barriers containing tapetal crystallites and melanin in the tips (also found in Setipinna taty), whereas Anchoviella alleni, Encrasicholina heteroloba, Engraulis encrasicolus, Engraulis mordax, Lycengraulis batesii, and Stolephorus indicus exhibit the typical polycone architecture. Cetengraulis mysticetus and Lycothrissa crocodilus show cone patterns and pigment epithelium morphology differing from the other anchovy species. The sets of characters are compared, corroborated with the previous knowledge on clupeoid retinae and discussed in terms of functional morphology and visual ecology. A scenario on polycone evolution is developed that may serve as an aid for the reconstruction of engraulidid phylogeny. Furthermore, this study demonstrates the suitability of museum material for morphological studies, even at the electron microscopic level.
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Affiliation(s)
- Martin Hess
- Biozentrum der Ludwig-Maximilians-Universität, Grosshadernerstrasse 2, 82152 Planegg-Martinsried, Germany.
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Reckel F, Melzer RR. Modifications of the falciform process in the eye of beloniformes (Teleostei: Atherinomorpha): evolution of a curtain-like septum in the eye. J Morphol 2004; 260:13-20. [PMID: 15052593 DOI: 10.1002/jmor.10215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In order to comparatively analyze curtain-like septa in the eyes of visually orientated "close-to-surface-predators" among atherinomorph teleosts, we examined the eyes of 24 atherinomorph species under a binocular microscope with regard to the falciform process and related structures in the vitreous cavity. Additionally, falciform process samples were analyzed by transmission electron microscopy. All the studied representatives of the Cyprinodontiformes and Atheriniformes, and of one of the beloniform suborder, Adrianichthyioidei, possess a "typical" processus falciformis. In the eyes of the representatives of the other beloniform suborder, Belonoidei, however, pigmented structures that originate in the region of the optic disc and protrude into the vitreous cavity were noted. In the Hemiramphidae (halfbeaks) and Exocoetidae (flying fishes) these pigmented structures have a more cone-like shape, whereas in the Belonidae (needlefishes) and Scomberesocidae (sauries) horizontally oriented heavily pigmented curtain-like septa occur that divide the vitreous cavity dorsoventrally. It is suggested that the "typical" processus falciformis represents a plesiomorphic feature within the Atherinomorpha, whereas the pigmented modifications of the falciform process must be seen as a synapomorphic character state of the Belonoidei. The curtain-like septum of the Belonidae and Scomberesocidae might have evolved from the cone-like structures that are found in the Exocoetoidea. The functional significance of the pigmented structures in the eye is as yet not clear, except for the curtain-like septum found in Belonidae. It might play a role in visual orientation near the water surface at Snell's window.
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Affiliation(s)
- Frank Reckel
- Department Biologie II, D-80333 München, Germany
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Reckel F, Melzer RR. Regional variations in the outer retina of atherinomorpha (Beloniformes, Atheriniformes, Cyprinodontiformes: Teleostei): photoreceptors, cone patterns, and cone densities. J Morphol 2003; 257:270-88. [PMID: 12833370 DOI: 10.1002/jmor.10122] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The outer retinae of adults of 13 atherinomorph species, representing nine different families, were examined by both light and electron microscopy. The retinae were investigated with respect to photoreceptor types, cone densities, and cone patterns. All data were composed to eye maps. This procedure allows an interspecific comparison of the regional differences within the outer retina among these shallow-water fish. Furthermore, for a more detailed pattern analysis nitro-blue tetrazolium chloride- (NBT)-stainings in the retina of Melanotaenia maccullochi are presented. Apart from rods, eight morphologically different cone types could be identified: short, intermediate, and long single cones, double cones (equal and unequal), triple cones (triangular and linear), and in Ameca splendens one quadruple cone. Dimensions and occurrence of photoreceptors vary among the respective species and within the retinal regions. In the light-adapted state, the cones are arranged in highly ordered mosaics. Five different cone tessellation types were found: row patterns, twisted row patterns, square patterns, pentagonal patterns, and, exclusively in Belone belone, a hexagonal pattern. In Melanotaenia maccullochi the different spectral photoreceptor classes correspond well with the distribution of morphological photoreceptor classes within the mosaic. Double cone density maxima together with a highly ordered cone arrangement usually occur in the nasal and/or ventral to ventrotemporal retina. In most of the species that were examined these high-density regions are presumed to process visual stimuli from the assumed main directions of vision, which mainly depend on feeding behavior and predator pressure. Our findings are discussed with respect to the variable behavioral and visual ecology and phylogeny of the respective species.
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Affiliation(s)
- Frank Reckel
- Department Biologie II, D-80333 München, Germany.
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Reckel F, Melzer RR, Parry JWL, Bowmaker JK. The retina of five atherinomorph teleosts: photoreceptors, patterns and spectral sensitivities. Brain Behav Evol 2003; 60:249-64. [PMID: 12476052 DOI: 10.1159/000067191] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We investigated the spectral and morphological features of the photoreceptors of five atherinomorph teleosts, representing two different orders, and with different life styles and habitats, the Beloniformes and Atheriniformes. The retinae of Belone belone (Belonidae), Dermogenys pusillus (Hemiramphidae), Atherina boyeri (Atherinidae), Marosatherina ladigesi (Telmatherinidae), and Melanotaenia maccullochi (Melanotaeniidae) were examined by light and electron microscopy and microspectrophotometry. In addition to rods, five morphologically different cone types were identified: short, intermediary and long single cones, and double cones which are arranged in distinct specific mosaics. Sporadically, triple cones were also found. Double cones were longer-wave-sensitive, but no general correlation between single cone morphology and spectral sensitivity could be demonstrated. The rods had lambda(max) close to 506-509 nm. The lambda(max) of cone visual pigments ranged from about 368 nm to 578 nm. Ultraviolet-sensitive single cones were present in the three freshwater species, M. ladigesi, M. maccullochi and D. pusillus and three spectrally distinct short-wave-sensitive single cone classes were identified in M. maccullochi. In M. ladigesi, spectral sensitivity varied among individuals due to varying rhodopsin/porphyropsin mixtures. In D. pusillus and M. maccullochi polymorphism of the longer-wave cone pigments might occur. These findings are discussed with respect to phylogeny, photic habitat, behavior and feeding habits.
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Affiliation(s)
- F Reckel
- Department Biologie II, and Zoologische Staatssammlung, München, Germany.
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Spreitzer A, Melzer RR. The Nymphal Eyes of Parabuthus transvaalicus Purcell, 1899 (Buthidae): An Accessory Lateral Eye in a Scorpion. ZOOL ANZ 2003. [DOI: 10.1078/0044-5231-00098] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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