1
|
Lustri L, Gueriau P, Daley AC. Lower Ordovician synziphosurine reveals early euchelicerate diversity and evolution. Nat Commun 2024; 15:3808. [PMID: 38714651 PMCID: PMC11076625 DOI: 10.1038/s41467-024-48013-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 04/18/2024] [Indexed: 05/10/2024] Open
Abstract
Euchelicerata is a clade of arthropods comprising horseshoe crabs, scorpions, spiders, mites and ticks, as well as the extinct eurypterids (sea scorpions) and chasmataspidids. The understanding of the ground plans and relationships between these crown-group euchelicerates has benefited from the discovery of numerous fossils. However, little is known regarding the origin and early evolution of the euchelicerate body plan because the relationships between their Cambrian sister taxa and synziphosurines, a group of Silurian to Carboniferous stem euchelicerates with chelicerae and an unfused opisthosoma, remain poorly understood owing to the scarce fossil record of appendages. Here we describe a synziphosurine from the Lower Ordovician (ca. 478 Ma) Fezouata Shale of Morocco. This species possesses five biramous appendages with stenopodous exopods bearing setae in the prosoma and a fully expressed first tergite in the opisthosoma illuminating the ancestral anatomy of the group. Phylogenetic analyses recover this fossil as a member of the stem euchelicerate family Offacolidae, which is characterized by biramous prosomal appendages. Moreover, it also shares anatomical features with the Cambrian euarthropod Habelia optata, filling the anatomical gap between euchelicerates and Cambrian stem taxa, while also contributing to our understanding of the evolution of euchelicerate uniramous prosomal appendages and tagmosis.
Collapse
Affiliation(s)
- Lorenzo Lustri
- Institute of Earth Sciences, University of Lausanne, Géopolis, Lausanne, Switzerland.
| | - Pierre Gueriau
- Institute of Earth Sciences, University of Lausanne, Géopolis, Lausanne, Switzerland
- Université Paris-Saclay, CNRS, ministère de la Culture, UVSQ, MNHN, Institut photonique d'analyse non-destructive européen des matériaux anciens, Saint-Aubin, France
| | - Allison C Daley
- Institute of Earth Sciences, University of Lausanne, Géopolis, Lausanne, Switzerland.
| |
Collapse
|
2
|
Napiórkowska T, Templin J, Napiórkowski P, Townley MA. Appendage abnormalities in spiders induced by an alternating temperature protocol in the context of recent advances in molecular spider embryology. PeerJ 2023; 11:e16011. [PMID: 37701827 PMCID: PMC10493090 DOI: 10.7717/peerj.16011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 08/10/2023] [Indexed: 09/14/2023] Open
Abstract
In the literature there are numerous reports of developmental deformities in arthropods collected in their natural habitat. Since such teratogenically affected individuals are found purely by chance, the causes of their defects are unknown. Numerous potential physical, mechanical, chemical, and biological teratogens have been considered and tested in the laboratory. Thermal shocks, frequently used in teratological research on the spider Eratigena atrica, have led to deformities on both the prosoma and the opisthosoma. In the 2020/2021 breeding season, by applying alternating temperatures (14 °C and 32 °C, changed every 12 h) for the first 10 days of embryonic development, we obtained 212 postembryos (out of 3,007) with the following anomalies: oligomely, heterosymely, bicephaly, schistomely, symely, polymely, complex anomalies, and others. From these we selected six spiders with defects on the prosoma and two with short appendages on the pedicel for further consideration. The latter cases seem particularly interesting because appendages do not normally develop on this body part, viewed as the first segment of the opisthosoma, and appear to represent examples of atavism. In view of the ongoing development of molecular techniques and recent research on developmental mechanisms in spiders, we believe the observed phenotypes may result, at least in part, from the erroneous suppression or expression of segmentation or appendage patterning genes. We consider "knockdown" experiments described in the literature as a means for generating hypotheses about the sources of temperature-induced body abnormalities in E. atrica.
Collapse
Affiliation(s)
- Teresa Napiórkowska
- Department of Invertebrate Zoology and Parasitology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Julita Templin
- Faculty of Biological and Veterinary Sciences, Department of Invertebrate Zoology and Parasitology, Nicolaus Copernicus University in Torun, Toruń, Poland
| | - Paweł Napiórkowski
- Department of Hydrobiology, Faculty of Biological Sciences, Kazimierz Wielki University in Bydgoszcz, Bydgoszcz, Poland
| | - Mark A. Townley
- University Instrumentation Center, University of New Hampshire, Durham, New Hampshire, United States
| |
Collapse
|
3
|
Plotnick RE, Bicknell RDC. The Eurypterid Endostoma and Its Homology with Other Chelicerate Structures. BULLETIN OF THE PEABODY MUSEUM OF NATURAL HISTORY 2022. [DOI: 10.3374/014.063.0202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Russell D. C. Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351 Australia
| |
Collapse
|
4
|
Aria C. The origin and early evolution of arthropods. Biol Rev Camb Philos Soc 2022; 97:1786-1809. [PMID: 35475316 DOI: 10.1111/brv.12864] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 12/18/2022]
Abstract
The rise of arthropods is a decisive event in the history of life. Likely the first animals to have established themselves on land and in the air, arthropods have pervaded nearly all ecosystems and have become pillars of the planet's ecological networks. Forerunners of this saga, exceptionally well-preserved Palaeozoic fossils recently discovered or re-discovered using new approaches and techniques have elucidated the precocious appearance of extant lineages at the onset of the Cambrian explosion, and pointed to the critical role of the plankton and hard integuments in early arthropod diversification. The notion put forward at the beginning of the century that the acquisition of extant arthropod characters was stepwise and represented by the majority of Cambrian fossil taxa is being rewritten. Although some key traits leading to Euarthropoda are indeed well documented along a diversified phylogenetic stem, this stem led to several speciose and ecologically diverse radiations leaving descendants late into the Palaeozoic, and a large part, if not all of the Cambrian euarthropods can now be placed on either of the two extant lineages: Mandibulata and Chelicerata. These new observations and discoveries have altered our view on the nature and timing of the Cambrian explosion and clarified diagnostic characters at the origin of extant arthropods, but also raised new questions, especially with respect to cephalic plasticity. There is now strong evidence that early arthropods shared a homologous frontalmost appendage, coined here the cheira, which likely evolved into antennules and chelicerae, but other aspects, such as brain and labrum evolution, are still subject to active debate. The early evolution of panarthropods was generally driven by increased mastication and predation efficiency and sophistication, but a wealth of recent studies have also highlighted the prevalent role of suspension-feeding, for which early panarthropods developed their own adaptive feedback through both specialized appendages and the diversification of small, morphologically differentiated larvae. In a context of general integumental differentiation and hardening across Cambrian metazoans, arthrodization of body and limbs notably prompted two diverging strategies of basipod differentiation, which arguably became founding criteria in the divergence of total-groups Mandibulata and Chelicerata. The kinship of trilobites and their relatives remains a source of disagreement, but a recent topological solution, termed the 'deep split', could embed Artiopoda as sister taxa to chelicerates and constitute definitive support for Arachnomorpha. Although Cambrian fossils have been critical to all these findings, data of exceptional quality have also been accumulating from other Palaeozoic Konservat-Lagerstätten, and a better integration of this information promises a much more complete and elaborate picture of early arthropod evolution in the near future. From the broader perspective of a total-evidence approach to the understanding of life's history, and despite persisting systematic debates and new interpretative challenges, various advances based on palaeontological evidence open the prospect of finally using the full potential of the most diverse animal phylum to investigate macroevolutionary patterns and processes.
Collapse
Affiliation(s)
- Cédric Aria
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing, 210008, P. R. China.,Shaanxi Key Laboratory of Early Life and Environments, Northwest University, Xi'an, 710069, P.R. China
| |
Collapse
|
5
|
Budd GE. The origin and evolution of the euarthropod labrum. ARTHROPOD STRUCTURE & DEVELOPMENT 2021; 62:101048. [PMID: 33862532 DOI: 10.1016/j.asd.2021.101048] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 05/16/2023]
Abstract
A widely (although not universally) accepted model of arthropod head evolution postulates that the labrum, a structure seen in almost all living euarthropods, evolved from an anterior pair of appendages homologous to the frontal appendages of onychophorans. However, the implications of this model for the interpretation of fossil arthropods have not been fully integrated into reconstructions of the euarthropod stem group, which remains in a state of some disorder. Here I review the evidence for the nature and evolution of the labrum from living taxa, and reconsider how fossils should be interpreted in the light of this. Identification of the segmental identity of head appendage in fossil arthropods remains problematic, and often rests ultimately on unproven assertions. New evidence from the Cambrian stem-group euarthropod Parapeytoia is presented to suggest that an originally protocerebral appendage persisted well up into the upper stem-group of the euarthropods, which prompts a re-evaluation of widely-accepted segmental homologies and the interpretation of fossil central nervous systems. Only a protocerebral brain was implicitly present in a large part of the euarthropod stem group, and the deutocerebrum must have been a relatively late addition.
Collapse
Affiliation(s)
- Graham E Budd
- Department of Earth Sciences, Palaeobiology Programme, Uppsala University, Villavägen 16, Uppsala, SE 752 36, Sweden.
| |
Collapse
|
6
|
Lustri L, Laibl L, Bicknell RD. A revision of Prolimulus woodwardi Fritsch, 1899 with comparison to other highly paedomorphic belinurids. PeerJ 2021; 9:e10980. [PMID: 33732551 PMCID: PMC7950201 DOI: 10.7717/peerj.10980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 01/30/2021] [Indexed: 01/02/2023] Open
Abstract
Xiphosurida is an ingroup of marine Euchelicerata often referred to as "living fossils". However, this oxymoronic term is inapplicable for Paleozoic and early Mesozoic forms, as during these periods the group experienced notable evolutionary radiations; particularly the diverse late Palaeozoic clade Belinurina. Despite the iconic nature of the group, select species in this clade have been left undescribed in the light of recent geometric morphometric and phylogenetic considerations and methodologies. To this end, we re-describe Prolimulus woodwardi Fritsch, 1899 using new and type specimens to reveal more details on appendage anatomy and possible ecology. Furthermore, we present geometric morphometric and phylogenetic analyses that uncover relationships between P. woodwardi and other belinurids without genal spines. Both approaches highlight that a clade containing Prolimulus Fritsch, 1899, Liomesaspis Raymond, 1944, Alanops Racheboeuf, Vannier & Anderson, 2002 and Stilpnocephalus Selden, Simonetto & Marsiglio, 2019 may exist. While we do not erect a new group to contain these genera, we note that these genera exemplify the extreme limits of the Belinurina radiation and a peak in horseshoe crab diversity and disparity. This evidence also illustrates how changes in heterochronic timing are a key evolutionary phenomenon that can drive radiations among animals.
Collapse
Affiliation(s)
- Lorenzo Lustri
- Institute of Earth Sciences, University of Lausanne, Geopolis, Lausanne, Switzerland
| | - Lukáš Laibl
- Institute of Geology and Palaeontology, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Geology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Russell D.C. Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia
| |
Collapse
|
7
|
Abstract
Xiphosurans are aquatic chelicerates with a fossil record extending into the Early Ordovician and known from a total of 88 described species, four of which are extant. Known for their apparent morphological conservatism, for which they have gained notoriety as supposed 'living fossils', recent analyses have demonstrated xiphosurans to have an ecologically diverse evolutionary history, with several groups moving into non-marine environments and developing morphologies markedly different from those of the modern species. The combination of their long evolutionary and complex ecological history along with their paradoxical patterns of morphological stasis in some clades and experimentation among others has resulted in Xiphosura being of particular interest for macroevolutionary study. Phylogenetic analyses have shown the current taxonomic framework for Xiphosura-set out in the Treatise of Invertebrate Paleontology in 1955-to be outdated and in need of revision, with several common genera such as Paleolimulus Dunbar, 1923 and Limulitella Størmer, 1952 acting as wastebasket taxa. Here, an expanded xiphosuran phylogeny is presented, comprising 58 xiphosuran species as part of a 158 taxon chelicerate matrix coded for 259 characters. Analysing the matrix under both Bayesian inference and parsimony optimisation criteria retrieves a concordant tree topology that forms the basis of a genus-level systematic revision of xiphosuran taxonomy. The genera Euproops Meek, 1867, Belinurus König, 1820, Paleolimulus, Limulitella, and Limulus are demonstrated to be non-monophyletic and the previously synonymized genera Koenigiella Raymond, 1944 and Prestwichianella Cockerell, 1905 are shown to be valid. In addition, nine new genera (Andersoniella gen. nov., Macrobelinurus gen. nov., and Parabelinurus gen. nov. in Belinurina; Norilimulus gen. nov. in Paleolimulidae; Batracholimulus gen. nov. and Boeotiaspis gen. nov. in Austrolimulidae; and Allolimulus gen. nov., Keuperlimulus gen. nov., and Volanalimulus gen. nov. in Limulidae) are erected to accommodate xiphosuran species not encompassed by existing genera. One new species, Volanalimulus madagascarensis gen. et sp. nov., is also described. Three putative xiphosuran genera-Elleria Raymond, 1944, Archeolimulus Chlupáč, 1963, and Drabovaspis Chlupáč, 1963-are determined to be non-xiphosuran arthropods and as such are removed from Xiphosura. The priority of Belinurus König, 1820 over Bellinurus Pictet, 1846 is also confirmed. This work is critical for facilitating the study of the xiphosuran fossil record and is the first step in resolving longstanding questions regarding the geographic distribution of the modern horseshoe crab species and whether they truly represent 'living fossils'. Understanding the long evolutionary history of Xiphosura is vital for interpreting how the modern species may respond to environmental change and in guiding conservation efforts.
Collapse
Affiliation(s)
- James C. Lamsdell
- Department of Geology and Geography, West Virginia University, Morgantown, WV, United States of America
| |
Collapse
|
8
|
Edgecombe GD. Arthropod Origins: Integrating Paleontological and Molecular Evidence. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-011720-124437] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Phylogenomics underpins a stable and mostly well-resolved hypothesis for the interrelationships of extant arthropods. Exceptionally preserved fossils are integrated into this framework by coding their morphological characters, as exemplified by total-evidence dating approaches that treat fossils as dated tips in analyses numerically dominated by molecular data. Cambrian fossils inform on the sequence of character acquisition in the arthropod stem group and in the stems of its main extant clades. The arthropod head problem incorporates unique appendage combinations and remains of the nervous system in fossils into a scheme mostly based on neuroanatomy and Hox expression domains for extant forms. Molecular estimates of arthropod origins in the Cryogenian or Ediacaran predate a coherent picture from the arthropod fossil record, which commences as trace fossils in the earliest Cambrian. Probabilistic morphological clock analysis of trilobites, which exemplify the earliest arthropod body fossils, supports a Cambrian origin, without the need to posit an unfossilized Ediacaran history.
Collapse
Affiliation(s)
- Gregory D. Edgecombe
- Department of Earth Sciences, The Natural History Museum, London SW7 5BD, United Kingdom
| |
Collapse
|
9
|
Howard RJ, Puttick MN, Edgecombe GD, Lozano-Fernandez J. Arachnid monophyly: Morphological, palaeontological and molecular support for a single terrestrialization within Chelicerata. ARTHROPOD STRUCTURE & DEVELOPMENT 2020; 59:100997. [PMID: 33039753 DOI: 10.1016/j.asd.2020.100997] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 06/11/2023]
Abstract
The majority of extant arachnids are terrestrial, but other chelicerates are generally aquatic, including horseshoe crabs, sea spiders, and the extinct eurypterids. It is necessary to determine whether arachnids are exclusively descended from a single common ancestor (monophyly), because only that relationship is compatible with one land colonisation in chelicerate evolutionary history. Some studies have cast doubt on arachnid monophyly and recast the origins of their terrestrialization. These include some phylogenomic analyses placing horseshoe crabs within Arachnida, and from aquatic Palaeozoic stem-group scorpions. Here, we evaluate the possibility of arachnid monophyly by considering morphology, fossils and molecules holistically. We argue arachnid monophyly obviates the need to posit reacquisition/retention of aquatic characters such as gnathobasic feeding and book gills without trabeculae from terrestrial ancestors in horseshoe crabs, and that the scorpion total-group contains few aquatic taxa. We built a matrix composed of 200 slowly-evolving genes and re-analysed two published molecular datasets. We retrieved arachnid monophyly where other studies did not - highlighting the difficulty of resolving chelicerate relationships from current molecular data. As such, we consider arachnid monophyly the best-supported hypothesis. Finally, we inferred that arachnids terrestrialized during the Cambrian-Ordovician using the slow-evolving molecular matrix, in agreement with recent analyses.
Collapse
Affiliation(s)
- Richard J Howard
- Department of Biosciences, University of Exeter, Penryn Campus, UK; Department of Earth Sciences, The Natural History Museum, UK.
| | - Mark N Puttick
- School of Biochemistry & Biological Sciences, University of Bath, Bath, UK
| | | | - Jesus Lozano-Fernandez
- Institute of Evolutionary Biology (CSIC-UPF), Barcelona, Spain; School of Biological Sciences, University of Bristol, Bristol, UK.
| |
Collapse
|
10
|
Bicknell RDC, Naugolnykh SV, Birch SA. A reappraisal of Paleozoic horseshoe crabs from Russia and Ukraine. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2020; 107:46. [PMID: 33009933 DOI: 10.1007/s00114-020-01701-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 09/08/2020] [Accepted: 09/17/2020] [Indexed: 10/23/2022]
Abstract
Xiphosura are extant marine chelicerates that have displayed apparent morphological conservatism and remarkable survivorship across their ~ 480 Ma fossil record. The easily recognisable features that are known to even the earliest xiphosurans-a crescentic prosoma and often trapezoidal thoracetron (opisthosoma)-have generated debate surrounding their origins and taxonomic significance. This interest resulted in the description of numerous horseshoe crab species during the early to mid-twentieth century, particularly in Russia, that have remained unrevised since their original publications and unconsidered in the light of recent phylogenetic hypotheses. Here, we re-examine the non-belinurid taxa housed within the Chernyshev Central Museum for Geological Exploration in Saint Petersburg. We present the first formal diagnosis of Bellinuroopsis rossicus, erect Shpineviolimulus jakovlevi (Glushenko and Ivanov, 1961) comb. nov., to contain the species formerly described as 'Paleolimulus' jakovlevi and refer Paleolimulus juresanensis to Paleolimulidae incertae sedis. Phylogenetic analysis places S. jakovlevi at the base of Limulina. This position, coupled with a prosomal shield that is notably larger than the thoracetron, and lack of hypertrophied genal spines, suggests that this morphology may represent the ancestral austrolimulid shape. As an extension of this revision, we assessed the general austrolimulid morphological characters and uncovered two possible groups of these bizarre xiphosurids.
Collapse
Affiliation(s)
- Russell D C Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, 2351, Australia.
| | - Serge V Naugolnykh
- Geological Institute, Russian Academy of Sciences, Moscow, Russia, 119117
| | - Sienna A Birch
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, 2351, Australia
| |
Collapse
|
11
|
Haug C. The evolution of feeding within Euchelicerata: data from the fossil groups Eurypterida and Trigonotarbida illustrate possible evolutionary pathways. PeerJ 2020. [DOI: 10.7717/peerj.9696] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
When the evolution of Euarthropoda is discussed, often the lineage of Chelicerata s. str. is assumed to be the more ‘primitive’ or ‘basal’ part of the tree, especially when compared to the other major lineage, Mandibulata. This claimed primitiveness is (at least partly) based on the assumption that different morphological structures are still in an ancestral state and did not evolve any further. One of these sets of structures is the feeding apparatus, which has been stated to be highly advanced in Mandibulata, but not ‘properly’ developed, or at least not to such a high degree, within Chelicerata s. str. In this study, I reinvestigate the feeding apparatus of different ingroups of Euchelicerata, with a focus on assumed ‘primitive’ groups such as Eurypterida and Trigonotarbida. The basis of this study is a large amount of material from different museum collections, with fossils with the entire feeding apparatuses being exceptionally well preserved. Based on high-resolution micro-photography and three-dimensional imaging, it is possible to resolve fine details of the feeding apparatuses. The results make clear that the feeding apparatuses of different ingroups of Euchelicerata are highly specialised and often possess morphological structures comparable to those of the feeding apparatuses of representatives of Mandibulata, apparently convergently evolved. Though the reconstruction of the evolution of the feeding apparatus within Euchelicerata is to a certain degree hampered by unclear phylogenetic relationships, there was clearly a shortening of the feeding apparatus from posterior (i.e. only the anterior appendages being involved in the feeding apparatus), probably linked to the colonisation of land in Arachnida.
Collapse
Affiliation(s)
- Carolin Haug
- Department of Biology II, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, Munich, Germany
| |
Collapse
|
12
|
Lerosey-Aubril R, Skabelund J, Ortega-Hernández J. Revision of the mollisoniid chelicerate(?) Thelxiope, with a new species from the middle Cambrian Wheeler Formation of Utah. PeerJ 2020; 8:e8879. [PMID: 32296605 PMCID: PMC7151752 DOI: 10.7717/peerj.8879] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/10/2020] [Indexed: 11/29/2022] Open
Abstract
The recent re-interpretation of the Lower Palaeozoic euarthropod group Mollisonia as belonging to Chelicerata has triggered a renewed interest for the poorly known family Mollisoniidae. In this contribution, we revise the anatomy, taxonomic diversity, and systematics of Thelxiope, the sister-taxon of Mollisonia. This mollisoniid genus comprises four species, and is characterized by the presence of one cephalic, seven thoracic (one per tergite), and three pygidial long sagittal spines. The type species, T. palaeothalassia Simonetta & Delle Cave, is a rare taxon in the Wuliuan Burgess Shale Formation of Canada, which can be recognized by the hypertrophy of a single of its sagittal spines, the posteriomost one. T. spinosa (Conway Morris & Robison)–a species originally assigned to a distinct genus ‘Ecnomocaris’ herein synonymised with Thelxiope–is known from a single specimen found in the Drumian Wheeler Formation of the House Range of Utah. It differs from the type-species in the hypertrophy of both the anteriormost (cephalic) and the posteriormost (third pygidial) sagittal spines. The same Wheeler strata have also yielded a single specimen of a new taxon, T. holmani sp. nov., which lacks hypertrophied sagittal spines and features blunt thoracic tergopleural tips. A putative fourth species, referred to Thelxiope sp. nov. A, extends the stratigraphical range of Thelxiope to the Lower Ordovician (Tremadocian), and its palaeographic range to West Gondwana. Currently under study, this relatively common component of the lower Fezouata Shale fauna is only briefly discussed. Features characterizing the genus Thelxiope and its components almost exclusively pertain to the sagittal spines, for the scarcity and inconsistent preservation of the Cambrian materials as-yet available preclude a confident assessment of the variability of other morphological features. The pygidium in Thelxiope and Mollisonia is not composed of four, but three tergites essentially similar to thoracic ones, except for the lack of articulations.
Collapse
Affiliation(s)
- Rudy Lerosey-Aubril
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA
| | | | - Javier Ortega-Hernández
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA
| |
Collapse
|
13
|
Schoenemann B, Poschmann M, Clarkson ENK. Insights into the 400 million-year-old eyes of giant sea scorpions (Eurypterida) suggest the structure of Palaeozoic compound eyes. Sci Rep 2019; 9:17797. [PMID: 31780700 PMCID: PMC6882788 DOI: 10.1038/s41598-019-53590-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 10/30/2019] [Indexed: 11/09/2022] Open
Abstract
Sea scorpions (Eurypterida, Chelicerata) of the Lower Devonian (~400 Mya) lived as large, aquatic predators. The structure of modern chelicerate eyes is very different from that of mandibulate compound eyes [Mandibulata: Crustacea and Tracheata (Hexapoda, such as insects, and Myriapoda)]. Here we show that the visual system of Lower Devonian (~400 Mya) eurypterids closely matches that of xiphosurans (Xiphosura, Chelicerata). Modern representatives of this group, the horseshoe crabs (Limulidae), have cuticular lens cylinders and usually also an eccentric cell in their sensory apparatus. This strongly suggests that the xiphosuran/eurypterid compound eye is a plesiomorphic structure with respect to the Chelicerata, and probably ancestral to that of Euchelicerata, including Eurypterida, Arachnida and Xiphosura. This is supported by the fact that some Palaeozoic scorpions also possessed compound eyes similar to those of eurypterids. Accordingly, edge enhancement (lateral inhibition), organised by the eccentric cell, most useful in scattered light-conditions, may be a very old mechanism, while the single-lens system of arachnids is possibly an adaptation to a terrestrial life-style.
Collapse
Affiliation(s)
- Brigitte Schoenemann
- University of Cologne, Zoology Department/ Neurobiology/Animal Physiology/Institute of Biology Education, Herbert-Lewin-Straße 10, D-50931, Cologne, Germany.
| | - Markus Poschmann
- Generaldirektion Kulturelles Erbe RLP, Direktion Landesarchäologie/Erdgeschichte, Niederberger Höhe 1, D-56077, Koblenz, Germany
| | - Euan N K Clarkson
- University of Edinburgh, Grant Institute, School of Geosciences, West Mains Road, Edinburgh, EH9 3JW, Scotland
| |
Collapse
|
14
|
Bicknell RDC, Pates S. Xiphosurid from the Tournaisian (Carboniferous) of Scotland confirms deep origin of Limuloidea. Sci Rep 2019; 9:17102. [PMID: 31745138 PMCID: PMC6863854 DOI: 10.1038/s41598-019-53442-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 10/31/2019] [Indexed: 11/09/2022] Open
Abstract
Horseshoe crabs are archetypal marine chelicerates with a fossil record extending from the Lower Ordovician to today. The major horseshoe crab groups are thought to have arisen in the middle to late Palaeozoic. Here we present the oldest known limuloid from the lower Carboniferous (Tournaisian stage, c. 350 million years ago) of Scotland: Albalimulus bottoni gen. et sp. nov. A comprehensive phylogenetic analysis supports the placement of A. bottoni as a representative of the extant family Limulidae and 100 million years older than any other limulid taxon. The use of geometric morphometric analyses corroborate the erection of the new taxon and illustrates the exploitation of morphospace by xiphosurids. This new taxon highlights the complex evolutionary history of xiphosurids and the importance of documenting these unique Palaeozoic individuals.
Collapse
Affiliation(s)
- Russell D C Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, 2351, Australia.
| | - Stephen Pates
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA
| |
Collapse
|
15
|
Simon C, Gordon ERL, Moulds MS, Cole JA, Haji D, Lemmon AR, Lemmon EM, Kortyna M, Nazario K, Wade EJ, Meister RC, Goemans G, Chiswell SM, Pessacq P, Veloso C, McCutcheon JP, Łukasik P. Off-target capture data, endosymbiont genes and morphology reveal a relict lineage that is sister to all other singing cicadas. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz120] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Phylogenetic asymmetry is common throughout the tree of life and results from contrasting patterns of speciation and extinction in the paired descendant lineages of ancestral nodes. On the depauperate side of a node, we find extant ‘relict’ taxa that sit atop long, unbranched lineages. Here, we show that a tiny, pale green, inconspicuous and poorly known cicada in the genus Derotettix, endemic to degraded salt-plain habitats in arid regions of central Argentina, is a relict lineage that is sister to all other modern cicadas. Nuclear and mitochondrial phylogenies of cicadas inferred from probe-based genomic hybrid capture data of both target and non-target loci and a morphological cladogram support this hypothesis. We strengthen this conclusion with genomic data from one of the cicada nutritional bacterial endosymbionts, Sulcia, an ancient and obligate endosymbiont of the larger plant-sucking bugs (Auchenorrhyncha) and an important source of maternally inherited phylogenetic data. We establish Derotettiginae subfam. nov. as a new, monogeneric, fifth cicada subfamily, and compile existing and new data on the distribution, ecology and diet of Derotettix. Our consideration of the palaeoenvironmental literature and host-plant phylogenetics allows us to predict what might have led to the relict status of Derotettix over 100 Myr of habitat change in South America.
Collapse
Affiliation(s)
- Chris Simon
- Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Eric R L Gordon
- Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - M S Moulds
- Australian Museum Research Institute, Sydney, NSW, Australia
| | - Jeffrey A Cole
- Natural Sciences Division, Pasadena City College, Pasadena, CA, USA
| | - Diler Haji
- Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Alan R Lemmon
- Department of Scientific Computing, Florida State University, Tallahassee, FL, USA
| | | | - Michelle Kortyna
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Katherine Nazario
- Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Elizabeth J Wade
- Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA
- Department of Natural Sciences and Mathematics, Curry College, Milton, MA, USA
| | - Russell C Meister
- Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Geert Goemans
- Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | | | - Pablo Pessacq
- Centro de Investigaciones Esquel de Montaña y Estepa Patagónicas, Esquel, Chubut, Argentina
| | - Claudio Veloso
- Department of Ecological Sciences, Science Faculty, University of Chile, Santiago, Chile
| | - John P McCutcheon
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Piotr Łukasik
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden
| |
Collapse
|
16
|
Bicknell RDC, Amati L, Ortega-Hernández J. New insights into the evolution of lateral compound eyes in Palaeozoic horseshoe crabs. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz065] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Abstract
Vision allows animals to interact with their environment. Aquatic chelicerates dominate the early record of lateral compound eyes among non-biomineralizing crown-group euarthropods. Although the conservative morphology of lateral eyes in Xiphosura is potentially plesiomorphic for Euarthropoda, synziphosurine eye organization has received little attention despite their early diverging phylogenetic position. Here, we re-evaluate the fossil evidence for lateral compound eyes in the synziphosurines Bunodes sp., Cyamocephalus loganensis, Legrandella lombardii, Limuloides limuloides, Pseudoniscus clarkei, Pseudoniscus falcatus and Pseudoniscus roosevelti. We compare these data with lateral eyes in the euchelicerates Houia yueya, Kasibelinurus amicorum and Lunataspis aurora. We find no convincing evidence for lateral eyes in most studied taxa, and Pseudoniscus roosevelti and Legrandella lombardii are the only synziphosurines with this feature. Our findings support two scenarios for euchelicerate lateral eye evolution. The elongate-crescentic lateral eyes of Legrandella lombardii might represent the ancestral organization, as suggested by the phylogenetic position of this taxon in stem-group Euchelicerata. Alternatively, the widespread occurrence of kidney-shaped lateral eyes in stem-group Xiphosura and stem-group Arachnida could represent the plesiomorphic condition; Legrandella lombardii eyes would therefore be derived. Both evolutionary scenarios support the interpretation that kidney-shaped lateral eyes are ancestral for crown-group Euchelicerata and morphologically conserved in extant Limulus polyphemus.
Collapse
Affiliation(s)
- Russell D C Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Lisa Amati
- Paleontology, New York State Museum, Albany, NY, USA
| | - Javier Ortega-Hernández
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| |
Collapse
|
17
|
|
18
|
Bicknell RDC, Pates S. Abnormal Extant Xiphosurids in the Yale Peabody Museum Invertebrate Zoology Collection. BULLETIN OF THE PEABODY MUSEUM OF NATURAL HISTORY 2019. [DOI: 10.3374/014.060.0102] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Stephen Pates
- Department of Zoology, University of Oxford, Oxford OX1 3PS United Kingdom
| |
Collapse
|
19
|
Ballesteros JA, Sharma PP. A Critical Appraisal of the Placement of Xiphosura (Chelicerata) with Account of Known Sources of Phylogenetic Error. Syst Biol 2019; 68:896-917. [DOI: 10.1093/sysbio/syz011] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 12/20/2018] [Accepted: 02/10/2019] [Indexed: 11/13/2022] Open
Abstract
AbstractHorseshoe crabs (Xiphosura) are traditionally regarded as sister group to the clade of terrestrial chelicerates (Arachnida). This hypothesis has been challenged by recent phylogenomic analyses, but the non-monophyly of Arachnida has consistently been disregarded as artifactual. We re-evaluated the placement of Xiphosura among chelicerates using the most complete phylogenetic data set to date, expanding outgroup sampling, and including data from whole genome sequencing projects. In spite of uncertainty in the placement of some arachnid clades, all analyses show Xiphosura consistently nested within Arachnida as the sister group to Ricinulei (hooded tick spiders). It is apparent that the radiation of arachnids is an old one and occurred over a brief period of time, resulting in several consecutive short internodes, and thus is a potential case for the confounding effects of incomplete lineage sorting (ILS). We simulated coalescent gene trees to explore the effects of increasing levels of ILS on the placement of horseshoe crabs. In addition, common sources of systematic error were evaluated, as well as the effects of fast-evolving partitions and the dynamics of problematic long branch orders. Our results indicated that the placement of horseshoe crabs cannot be explained by missing data, compositional biases, saturation, or ILS. Interrogation of the phylogenetic signal showed that the majority of loci favor the derived placement of Xiphosura over a monophyletic Arachnida. Our analyses support the inference that horseshoe crabs represent a group of aquatic arachnids, comparable to aquatic mites, breaking a long-standing paradigm in chelicerate evolution and altering previous interpretations of the ancestral transition to the terrestrial habitat. Future studies testing chelicerate relationships should approach the task with a sampling strategy where the monophyly of Arachnida is not held as the premise.
Collapse
Affiliation(s)
- Jesús A Ballesteros
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Prashant P Sharma
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| |
Collapse
|
20
|
Lamsdell JC, Gunderson GO, Meyer RC. A common arthropod from the Late Ordovician Big Hill Lagerstätte (Michigan) reveals an unexpected ecological diversity within Chasmataspidida. BMC Evol Biol 2019; 19:8. [PMID: 30621579 PMCID: PMC6325806 DOI: 10.1186/s12862-018-1329-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/13/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Chasmataspidids are a rare group of chelicerate arthropods known from 12 species assigned to ten genera, with a geologic range extending from the Ordovician to the Devonian. The Late Ordovician (Richmondian) fauna of the Big Hill Lagerstätte includes a new species of chasmataspidid represented by 55 specimens. This taxon is only the second chasmataspidid described from the Ordovician and preserves morphological details unknown from any of the previously described species. RESULTS The new chasmataspidid species is described as Hoplitaspis hiawathai gen. et sp. nov.. Comparison with all other known chasmataspidids indicates that Hoplitaspis occupies an intermediate morphological position between the Ordovician Chasmataspis and the Silurian-Devonian diploaspidids. While the modification of appendage VI into a broad swimming paddle allies Hoplitaspis to the Diploaspididae, the paddle lacks the anterior 'podomere 7a' found in other diploaspidids and shows evidence of having been derived from a Chasmataspis-like chelate appendage. Other details, such as the large body size and degree of expression of the first tergite, show clear affinities with Chasmataspis, providing strong support for chasmataspidid monophyly. CONCLUSIONS The large body size and well-developed appendage armature of Hoplitaspis reveals that chasmataspidids occupied a greater breadth of ecological roles than previously thought, with the abundance of available specimens indicating that Hoplitaspis was an important component of the local community. The miniaturization and ecological limiting of diploaspidids potentially coincides with the major radiation of eurypterids and may suggest some degree of competition between the two groups. The geographic distribution of chasmataspidid species suggests the group may have originated in Laurentia and migrated to the paleocontinents of Baltica and Siberia as tectonic processes drew the paleocontinents into close proximity.
Collapse
Affiliation(s)
- James C. Lamsdell
- Department of Geology and Geography, West Virginia University, 98 Beechurst Avenue, Brooks Hall, Morgantown, WV 26501 USA
| | | | | |
Collapse
|
21
|
Dunlop JA. Miniaturisation in Chelicerata. ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 48:20-34. [PMID: 30367936 DOI: 10.1016/j.asd.2018.10.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/11/2018] [Accepted: 10/12/2018] [Indexed: 06/08/2023]
Abstract
Arachnids and their relatives (Chelicerata) range in body length from tens of centimetres in horseshoe crabs down to little more than 80-200 μm in several groups of mites. Spiders (Araneae) show the widest range within a given Bauplan - the largest species being ca. 270 times longer than the smallest - making them excellent models to investigate scaling effects. The two mite clades (Parasitiformes and Acariformes) are the main specialists in being small. Miniaturisation, and its consequences, is reviewed for both fossil and extant chelicerates. Morphological changes potentially related to miniaturisation, or adapting to the ecological niches that small size allows, include reduction in the length and number of legs, loss of prosomal arteries (and eventually also the heart), replacement of book lungs by tracheae, or even loss of all respiratory organs. There may also be evolutionary novelties, such as the acquisition of structures by which some mites attach themselves to larger hosts. The observed character distributions suggest a fairly fundamental division between larger pulmonate (lung-bearing) arachnids and smaller, non-pulmonate, groups which could reflect a phylogenetic dichotomy. However, it is worth noting that lineages of tiny spiders were originally fully pulmonate, but have acquired some typically non-pulmonate features, while camel spiders (Soli-fugae) can be large but have a Bauplan suggestive of smaller, non-pulmonate, ancestors.
Collapse
Affiliation(s)
- Jason A Dunlop
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, Berlin D-10115, Germany
| |
Collapse
|
22
|
Lamsdell JC, Marshall DJ, Briggs DEG. Hit and Miss: (A Comment on Persons and Acorn, “A Sea Scorpion’s Strike: New Evidence of Extreme Lateral Flexibility in the Opisthosoma of Eurypterids”). Am Nat 2018. [DOI: 10.1086/695955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
23
|
Barrales-Alcalá D, Francke OF, Prendini L. Systematic Revision of the Giant Vinegaroons of theMastigoproctus giganteusComplex (Thelyphonida: Thelyphonidae) of North America. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2018. [DOI: 10.1206/0003-0090-418.1.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Diego Barrales-Alcalá
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México; Colección Nacional de Arácnidos, Departamento de Zoologia, Instituto de Biología, Universidad Nacional Autónoma de México
| | - Oscar F. Francke
- Colección Nacional de Arácnidos, Departamento de Zoologia, Instituto de Biología, Universidad Nacional Autónoma de México
| | - Lorenzo Prendini
- Division of Invertebrate Zoology, American Museum of Natural History
| |
Collapse
|
24
|
Haug C, Rötzer MAIN. The ontogeny of Limulus polyphemus (Xiphosura s. str., Euchelicerata) revised: looking "under the skin". Dev Genes Evol 2018; 228:49-61. [PMID: 29380035 DOI: 10.1007/s00427-018-0603-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 01/09/2018] [Indexed: 01/20/2023]
Abstract
In recent years, methods for investigating the exo-morphology of zoological specimens have seen large improvements. Among new approaches, auto-fluorescence imaging offers possibilities to document specimens under high resolution without introducing additional artifacts as, for example, seen in scanning electron microscopy (SEM) imaging. Additionally, while SEM imaging is restricted to the outer morphology of the current instar, auto-fluorescence imaging can be used to document changes of the outer morphology of the next instar underneath the cuticle of the current instar. Thus, reinvestigating seemingly well known species with these methods may lead to interesting new insights. Here we reinvestigate the late embryonic development of the xiphosuran ("sword tail") Limulus polyphemus, which is often treated as a proxy for early eucheliceratan evolution. In addition to entire specimens, the appendages of the embryos were dissected off and documented separately with composite-autofluorescence microscopy. Based on these data, we can distinguish six developmental stages. These stages do not match exactly the formerly described stages, as these were largely based on SEM investigation. Our stages appear to represent earlier or later phases within what has in other studies been identified as one stage. This finer subdivision is visible as we can see the developing cuticle under the outer cuticle. In comparison to data from fossil xiphosurans, our results and those of other studies on the ontogeny of L. polyphemus point to a derived mode of development in this species, which argues against the idea of L. polyphemus as a "living fossil."
Collapse
Affiliation(s)
- Carolin Haug
- Department of Biology II, LMU Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany.
- GeoBio-Center of the LMU Munich, Richard-Wagner-Str. 10, 82152, Munich, Germany.
| | - Marie A I N Rötzer
- Department of Biology II, LMU Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
| |
Collapse
|
25
|
Haug C, Rötzer MAIN. The ontogeny of the 300 million year old xiphosuran Euproops danae (Euchelicerata) and implications for resolving the Euproops species complex. Dev Genes Evol 2018; 228:63-74. [PMID: 29362894 DOI: 10.1007/s00427-018-0604-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 01/09/2018] [Indexed: 11/29/2022]
Abstract
Xiphosurans have often been considered as archaic appearing cheliceratan arthropods, with a rich fossil record. We describe here parts of the post-embryonic ontogeny of the 300 million year old xiphosuran Euproops danae (Xiphosura sensu stricto, Euchelicerata), from the Mazon Creek Lagerstätte (Upper Carboniferous), USA. Recently, the ontogeny of a closely related species, Euproops sp. from the Upper Carboniferous Piesberg quarry, Osnabrück, Germany (informally called 'Piesproops'), has been reconstructed. This analysis has drawn characters into question that were used to differentiate E. danae from another species occurring at the same time, Euproops rotundatus from the British Middle Coal Measures. More precisely, early post-embryonic stages of Piesproops resemble E. danae; later stages resemble E. rotundatus. Based on this earlier study, the here-described reinvestigation of E. danae has been performed as the ontogenetic sequence itself may yield more reliable characters for differentiating species of Euproops. We could identify eight different growth stages for E. danae. This ontogenetic sequence shows a comparable growth to that of Piesproops, but differs markedly in the development of the opisthosomal flange. This character may serve as a basis for reliably differentiating these species. Additionally, analysing the ontogeny of further species may offer the basis for identifying heterochronic shifts in the evolution of xiphosurans.
Collapse
Affiliation(s)
- Carolin Haug
- Department of Biology II, LMU Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany. .,GeoBio-Center of the LMU Munich, Richard-Wagner-Str. 10, 80333, Munich, Germany.
| | - Marie A I N Rötzer
- Department of Biology II, LMU Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
| |
Collapse
|
26
|
Bicknell RDC, Paterson JR, Caron JB, Skovsted CB. The gnathobasic spine microstructure of recent and Silurian chelicerates and the Cambrian artiopodan Sidneyia: Functional and evolutionary implications. ARTHROPOD STRUCTURE & DEVELOPMENT 2018; 47:12-24. [PMID: 29221679 DOI: 10.1016/j.asd.2017.12.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/04/2017] [Accepted: 12/04/2017] [Indexed: 06/07/2023]
Abstract
Gnathobasic spines are located on the protopodal segments of the appendages of various euarthropod taxa, notably chelicerates. Although they are used to crush shells and masticate soft food items, the microstructure of these spines are relatively poorly known in both extant and extinct forms. Here we compare the gnathobasic spine microstructures of the Silurian eurypterid Eurypterus tetragonophthalmus from Estonia and the Cambrian artiopodan Sidneyiainexpectans from Canada with those of the Recent xiphosuran chelicerate Limulus polyphemus to infer potential variations in functional morphology through time. The thickened fibrous exocuticle in L. polyphemus spine tips enables effective prey mastication and shell crushing, while also reducing pressure on nerve endings that fill the spine cavities. The spine cuticle of E. tetragonophthalmus has a laminate structure and lacks the fibrous layers seen in L. polyphemus spines, suggesting that E. tetragonophthalmus may not have been capable of crushing thick shells, but a durophagous habit cannot be precluded. Conversely, the cuticle of S. inexpectans spines has a similar fibrous microstructure to L. polyphemus, suggesting that S. inexpectans was a competent shell crusher. This conclusion is consistent with specimens showing preserved gut contents containing various shelly fragments. The shape and arrangement of the gnathobasic spines is similar for both L. polyphemus and S. inexpectans, with stouter spines in the posterior cephalothoracic or trunk appendages, respectively. This differentiation indicates that crushing occurs posteriorly, while the gnathobases on anterior appendages continue mastication and push food towards and into the mouth. The results of recent phylogenetic analyses that considered both modern and fossil euarthropod clades show that xiphosurans and eurypterids are united as crown-group euchelicerates, with S. inexpectans placed within more basal artiopodan clades. These relationships suggest that gnathobases with thickened fibrous exocuticle, if not homoplasious, may be plesiomorphic for chelicerates and deeper relatives within Arachnomorpha. This study shows that the gnathobasic spine microstructure best adapted for durophagy has remained remarkably constant since the Cambrian.
Collapse
Affiliation(s)
- Russell D C Bicknell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.
| | - John R Paterson
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.
| | - Jean-Bernard Caron
- Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada; Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 2J7, Canada; Department of Earth Sciences, University of Toronto, Toronto, Ontario, M5S 3B1, Canada.
| | - Christian B Skovsted
- Department of Palaeobiology, Swedish Museum of Natural History, PO Box 50007, SE-104 05, Stockholm, Sweden.
| |
Collapse
|
27
|
Aria C, Caron JB. Mandibulate convergence in an armoured Cambrian stem chelicerate. BMC Evol Biol 2017; 17:261. [PMID: 29262772 PMCID: PMC5738823 DOI: 10.1186/s12862-017-1088-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 11/21/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chelicerata represents a vast clade of mostly predatory arthropods united by a distinctive body plan throughout the Phanerozoic. Their origins, however, with respect to both their ancestral morphological features and their related ecologies, are still poorly understood. In particular, it remains unclear whether their major diagnostic characters were acquired early on, and their anatomical organization rapidly constrained, or if they emerged from a stem lineage encompassing an array of structural variations, based on a more labile "panchelicerate" body plan. RESULTS In this study, we reinvestigated the problematic middle Cambrian arthropod Habelia optata Walcott from the Burgess Shale, and found that it was a close relative of Sanctacaris uncata Briggs and Collins (in Habeliida, ord. nov.), both retrieved in our Bayesian phylogeny as stem chelicerates. Habelia possesses an exoskeleton covered in numerous spines and a bipartite telson as long as the rest of the body. Segments are arranged into three tagmata. The prosoma includes a reduced appendage possibly precursor to the chelicera, raptorial endopods connected to five pairs of outstandingly large and overlapping gnathobasic basipods, antennule-like exopods seemingly dissociated from the main limb axis, and, posteriorly, a pair of appendages morphologically similar to thoracic ones. While the head configuration of habeliidans anchors a seven-segmented prosoma as the chelicerate ground pattern, the peculiar size and arrangement of gnathobases and the presence of sensory/tactile appendages also point to an early convergence with the masticatory head of mandibulates. CONCLUSIONS Although habeliidans illustrate the early appearance of some diagnostic chelicerate features in the evolution of euarthropods, the unique convergence of their cephalons with mandibulate anatomies suggests that these traits retained an unusual variability in these taxa. The common involvement of strong gnathal appendages across non-megacheirans Cambrian taxa also illustrates that the specialization of the head as the dedicated food-processing tagma was critical to the emergence of both lineages of extant euarthropods-Chelicerata and Mandibulata-and implies that this diversification was facilitated by the expansion of durophagous niches.
Collapse
Affiliation(s)
- Cédric Aria
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S3B2, Canada.
- Present address: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Jean-Bernard Caron
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S3B2, Canada
- Department of Natural History (Palaeobiology Section), Royal Ontario Museum, Toronto, ON, M5S2C6, Canada
- Department of Earth Sciences, University of Toronto, Toronto, ON, M5S3B1, Canada
| |
Collapse
|
28
|
Hu S, Zhang Q, Feldmann RM, Benton MJ, Schweitzer CE, Huang J, Wen W, Zhou C, Xie T, Lü T, Hong S. Exceptional appendage and soft-tissue preservation in a Middle Triassic horseshoe crab from SW China. Sci Rep 2017; 7:14112. [PMID: 29075039 PMCID: PMC5658423 DOI: 10.1038/s41598-017-13319-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/20/2017] [Indexed: 11/23/2022] Open
Abstract
Horseshoe crabs are classic "living fossils", supposedly slowly evolving, conservative taxa, with a long fossil record back to the Ordovician. The evolution of their exoskeleton is well documented by fossils, but appendage and soft-tissue preservation is extremely rare. Here we analyse details of appendage and soft-tissue preservation in Yunnanolimulus luopingensis, a Middle Triassic (ca. 244 million years old) horseshoe crab from Yunnan Province, SW China. The remarkable preservation of anatomical details including the chelicerae, five pairs of walking appendages, opisthosomal appendages with book gills, muscles, and fine setae permits comparison with extant horseshoe crabs. The close anatomical similarity between the Middle Triassic horseshoe crabs and their recent analogues documents anatomical conservatism for over 240 million years, suggesting persistence of lifestyle. The occurrence of Carcinoscorpius-type claspers on the first and second walking legs in male individuals of Y. luopingensis indicates that simple chelate claspers in males are plesiomorphic for horseshoe crabs, and the bulbous claspers in Tachypleus and Limulus are derived.
Collapse
Affiliation(s)
- Shixue Hu
- Chengdu Center, China Geological Survey, Chengdu, 610081, China.
- Chengdu Insitute of Geology and Mineral Resources, Chengdu, 610081, China.
| | - Qiyue Zhang
- Chengdu Center, China Geological Survey, Chengdu, 610081, China
- Chengdu Insitute of Geology and Mineral Resources, Chengdu, 610081, China
| | | | - Michael J Benton
- School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK
| | - Carrie E Schweitzer
- Department of Geology, Kent State University at Stark, 6000 Frank Avenue NW, North Canton, OH, 44720, USA
| | - Jinyuan Huang
- Chengdu Center, China Geological Survey, Chengdu, 610081, China
- Chengdu Insitute of Geology and Mineral Resources, Chengdu, 610081, China
| | - Wen Wen
- Chengdu Center, China Geological Survey, Chengdu, 610081, China
- Chengdu Insitute of Geology and Mineral Resources, Chengdu, 610081, China
| | - Changyong Zhou
- Chengdu Center, China Geological Survey, Chengdu, 610081, China
- Chengdu Insitute of Geology and Mineral Resources, Chengdu, 610081, China
| | - Tao Xie
- Chengdu Center, China Geological Survey, Chengdu, 610081, China
- Chengdu Insitute of Geology and Mineral Resources, Chengdu, 610081, China
| | - Tao Lü
- Chengdu Center, China Geological Survey, Chengdu, 610081, China
- Chengdu Insitute of Geology and Mineral Resources, Chengdu, 610081, China
| | - Shuigen Hong
- Institute of Neuroscience, Xiamen University, Xiamen, 361005, China
| |
Collapse
|
29
|
Dunlop JA, Lamsdell JC. Segmentation and tagmosis in Chelicerata. ARTHROPOD STRUCTURE & DEVELOPMENT 2017; 46:395-418. [PMID: 27240897 DOI: 10.1016/j.asd.2016.05.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/17/2016] [Accepted: 05/18/2016] [Indexed: 05/16/2023]
Abstract
Patterns of segmentation and tagmosis are reviewed for Chelicerata. Depending on the outgroup, chelicerate origins are either among taxa with an anterior tagma of six somites, or taxa in which the appendages of somite I became increasingly raptorial. All Chelicerata have appendage I as a chelate or clasp-knife chelicera. The basic trend has obviously been to consolidate food-gathering and walking limbs as a prosoma and respiratory appendages on the opisthosoma. However, the boundary of the prosoma is debatable in that some taxa have functionally incorporated somite VII and/or its appendages into the prosoma. Euchelicerata can be defined on having plate-like opisthosomal appendages, further modified within Arachnida. Total somite counts for Chelicerata range from a maximum of nineteen in groups like Scorpiones and the extinct Eurypterida down to seven in modern Pycnogonida. Mites may also show reduced somite counts, but reconstructing segmentation in these animals remains challenging. Several innovations relating to tagmosis or the appendages borne on particular somites are summarised here as putative apomorphies of individual higher taxa. We also present our observations within the concept of pseudotagma, whereby the true tagmata - the prosoma and opisthosoma - can be defined on a fundamental change in the limb series while pseudotagmata, such as the cephalosoma/proterosoma, are expressed as divisions in sclerites covering the body without an accompanying change in the appendages.
Collapse
Affiliation(s)
- Jason A Dunlop
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, D-10115 Berlin, Germany.
| | - James C Lamsdell
- American Museum of Natural History, Division of Paleontology, Central Park West at 79th St, New York, NY 10024, USA.
| |
Collapse
|
30
|
Zuber M, Laaß M, Hamann E, Kretschmer S, Hauschke N, van de Kamp T, Baumbach T, Koenig T. Augmented laminography, a correlative 3D imaging method for revealing the inner structure of compressed fossils. Sci Rep 2017; 7:41413. [PMID: 28128302 PMCID: PMC5269749 DOI: 10.1038/srep41413] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 12/19/2016] [Indexed: 11/09/2022] Open
Abstract
Non-destructive imaging techniques can be extremely useful tools for the investigation and the assessment of palaeontological objects, as mechanical preparation of rare and valuable fossils is precluded in most cases. However, palaeontologists are often faced with the problem of choosing a method among a wide range of available techniques. In this case study, we employ x-ray computed tomography (CT) and computed laminography (CL) to study the first fossil xiphosuran from the Muschelkalk (Middle Triassic) of the Netherlands. The fossil is embedded in micritic limestone, with the taxonomically important dorsal shield invisible, and only the outline of its ventral part traceable. We demonstrate the complementarity of CT and CL which offers an excellent option to visualize characteristic diagnostic features. We introduce augmented laminography to correlate complementary information of the two methods in Fourier space, allowing to combine their advantages and finally providing increased anatomical information about the fossil. This method of augmented laminography enabled us to identify the xiphosuran as a representative of the genus Limulitella.
Collapse
Affiliation(s)
- Marcus Zuber
- Karlsruhe Institute of Technology (KIT), Institute for Photon Science and Synchrotron Radiation (IPS) &Institute for Beam Physics and Technology (IBPT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.,Karlsruhe Institute of Technology (KIT), Laboratory for Applications of Synchrotron Radiation (LAS), Kaiserstr. 12, 76131 Karlsruhe, Germany
| | - Michael Laaß
- University of Duisburg-Essen, Department of General Zoology, Faculty of Biology, Universitätsstr. 5, 45117 Essen, Germany
| | - Elias Hamann
- Karlsruhe Institute of Technology (KIT), Institute for Photon Science and Synchrotron Radiation (IPS) &Institute for Beam Physics and Technology (IBPT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Sophie Kretschmer
- Martin-Luther-University Halle-Wittenberg, Institute of Geosciences and Geography, Von-Seckendorff-Platz 3, 06120 Halle (Saale), Germany
| | - Norbert Hauschke
- Martin-Luther-University Halle-Wittenberg, Institute of Geosciences and Geography, Von-Seckendorff-Platz 3, 06120 Halle (Saale), Germany
| | - Thomas van de Kamp
- Karlsruhe Institute of Technology (KIT), Institute for Photon Science and Synchrotron Radiation (IPS) &Institute for Beam Physics and Technology (IBPT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.,Karlsruhe Institute of Technology (KIT), Laboratory for Applications of Synchrotron Radiation (LAS), Kaiserstr. 12, 76131 Karlsruhe, Germany
| | - Tilo Baumbach
- Karlsruhe Institute of Technology (KIT), Institute for Photon Science and Synchrotron Radiation (IPS) &Institute for Beam Physics and Technology (IBPT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.,Karlsruhe Institute of Technology (KIT), Laboratory for Applications of Synchrotron Radiation (LAS), Kaiserstr. 12, 76131 Karlsruhe, Germany
| | - Thomas Koenig
- Karlsruhe Institute of Technology (KIT), Institute for Photon Science and Synchrotron Radiation (IPS) &Institute for Beam Physics and Technology (IBPT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.,Ziehm Imaging GmbH, Donaustr. 31, 90451 Nuremberg, Germany
| |
Collapse
|
31
|
Lozano-Fernandez J, Carton R, Tanner AR, Puttick MN, Blaxter M, Vinther J, Olesen J, Giribet G, Edgecombe GD, Pisani D. A molecular palaeobiological exploration of arthropod terrestrialization. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150133. [PMID: 27325830 PMCID: PMC4920334 DOI: 10.1098/rstb.2015.0133] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/29/2016] [Indexed: 12/28/2022] Open
Abstract
Understanding animal terrestrialization, the process through which animals colonized the land, is crucial to clarify extant biodiversity and biological adaptation. Arthropoda (insects, spiders, centipedes and their allies) represent the largest majority of terrestrial biodiversity. Here we implemented a molecular palaeobiological approach, merging molecular and fossil evidence, to elucidate the deepest history of the terrestrial arthropods. We focused on the three independent, Palaeozoic arthropod terrestrialization events (those of Myriapoda, Hexapoda and Arachnida) and showed that a marine route to the colonization of land is the most likely scenario. Molecular clock analyses confirmed an origin for the three terrestrial lineages bracketed between the Cambrian and the Silurian. While molecular divergence times for Arachnida are consistent with the fossil record, Myriapoda are inferred to have colonized land earlier, substantially predating trace or body fossil evidence. An estimated origin of myriapods by the Early Cambrian precedes the appearance of embryophytes and perhaps even terrestrial fungi, raising the possibility that terrestrialization had independent origins in crown-group myriapod lineages, consistent with morphological arguments for convergence in tracheal systems.This article is part of the themed issue 'Dating species divergences using rocks and clocks'.
Collapse
Affiliation(s)
- Jesus Lozano-Fernandez
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Robert Carton
- Department of Biology, The National University of Ireland Maynooth, Maynooth, Kildare, Ireland
| | - Alastair R Tanner
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Mark N Puttick
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Mark Blaxter
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3TF, UK
| | - Jakob Vinther
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Jørgen Olesen
- Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Gonzalo Giribet
- Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - Gregory D Edgecombe
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Davide Pisani
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| |
Collapse
|
32
|
Daley AC, Drage HB. The fossil record of ecdysis, and trends in the moulting behaviour of trilobites. ARTHROPOD STRUCTURE & DEVELOPMENT 2016; 45:71-96. [PMID: 26431634 DOI: 10.1016/j.asd.2015.09.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 09/01/2015] [Accepted: 09/14/2015] [Indexed: 06/05/2023]
Abstract
Ecdysis, the process of moulting an exoskeleton, is one of the key characters uniting arthropods, nematodes and a number of smaller phyla into Ecdysozoa. The arthropod fossil record, particularly trilobites, eurypterids and decapod crustaceans, yields information on moulting, although the current focus is predominantly descriptive and lacks a broader evolutionary perspective. We here review literature on the fossil record of ecdysis, synthesising research on the behaviour, evolutionary trends, and phylogenetic significance of moulting throughout the Phanerozoic. Approaches vary widely between taxonomic groups, but an overall theme uniting these works suggests that identifying moults in the palaeontological record must take into account the morphology, taphonomy and depositional environment of fossils. We also quantitatively analyse trends in trilobite ecdysis based on a newly generated database of published incidences of moulting behaviour. This preliminary work reveals significant taxonomic and temporal signal in the trilobite moulting fossil record, with free cheek moulting being prevalent across all Orders and throughout the Phanerozoic, and peaks of cephalic moulting in Phacopida during the Ordovician and rostral plate moulting in Redlichiida during the Cambrian. This study and a review of the literature suggest that it is feasible to extract large-scale evolutionary information from the fossil record of moulting.
Collapse
Affiliation(s)
- Allison C Daley
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom; Oxford University Museum of Natural History, Parks Road, Oxford, OX1 3PZ, United Kingdom.
| | - Harriet B Drage
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom; Oxford University Museum of Natural History, Parks Road, Oxford, OX1 3PZ, United Kingdom
| |
Collapse
|
33
|
Lamsdell JC, Briggs DEG, Liu HP, Witzke BJ, McKay RM. A new Ordovician arthropod from the Winneshiek Lagerstätte of Iowa (USA) reveals the ground plan of eurypterids and chasmataspidids. Naturwissenschaften 2015; 102:63. [DOI: 10.1007/s00114-015-1312-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/01/2015] [Accepted: 09/04/2015] [Indexed: 11/24/2022]
|
34
|
Lamsdell JC, Briggs DEG, Liu HP, Witzke BJ, McKay RM. The oldest described eurypterid: a giant Middle Ordovician (Darriwilian) megalograptid from the Winneshiek Lagerstätte of Iowa. BMC Evol Biol 2015; 15:169. [PMID: 26324341 PMCID: PMC4556007 DOI: 10.1186/s12862-015-0443-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/30/2015] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Eurypterids are a diverse group of chelicerates known from ~250 species with a sparse Ordovician record currently comprising 11 species; the oldest fully documented example is from the Sandbian of Avalonia. The Middle Ordovician (Darriwilian) fauna of the Winneshiek Lagerstätte includes a new eurypterid species represented by more than 150 specimens, including some juveniles, preserved as carbonaceous cuticular remains. This taxon represents the oldest described eurypterid, extending the documented range of the group back some 9 million years. RESULTS The new eurypterid species is described as Pentecopterus decorahensis gen. et sp. nov.. Phylogenetic analysis places Pentecopterus at the base of the Megalograptidae, united with the two genera previously assigned to this family by the shared possession of two or more pairs of spines per podomere on prosomal appendage IV, a reduction of all spines except the pair on the penultimate podomere of appendage V, and an ornamentation of guttalate scales, including angular scales along the posterior margin of the dorsal tergites and in longitudinal rows along the tergites. The morphology of Pentecopterus reveals that the Megalograptidae are representatives of the derived carcinosomatoid clade and not basal eurypterids as previously interpreted. CONCLUSIONS The relatively derived position of megalograptids within the eurypterids indicates that most eurypterid clades were present by the Middle Ordovician. Eurypterids either underwent an explosive radiation soon after their origination, or earlier representatives, perhaps Cambrian in age, remain to be discovered. The available instars of Pentecopterus decorahensis suggest that eurypterids underwent extreme appendage differentiation during development, a potentially unique condition among chelicerates. The high degree of appendage specialization in eurypterids is only matched by arachnids within chelicerates, supporting a sister taxon relationship between them.
Collapse
Affiliation(s)
- James C Lamsdell
- Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT, 06511, USA.
| | - Derek E G Briggs
- Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT, 06511, USA.
- Yale Peabody Museum of Natural History, Yale University, New Haven, CT, 06511, USA.
| | - Huaibao P Liu
- Iowa Geological Survey, IIHR-Hydroscience & Engineering, University of Iowa, 340 Trowbridge Hall, Iowa City, IA, 52242, USA.
| | - Brian J Witzke
- Department of Earth and Environmental Sciences, University of Iowa, 121 Trowbridge Hall, Iowa City, IA, 52242, USA.
| | - Robert M McKay
- Iowa Geological Survey, IIHR-Hydroscience & Engineering, University of Iowa, 340 Trowbridge Hall, Iowa City, IA, 52242, USA.
| |
Collapse
|
35
|
Tachypleus syriacus (Woodward)—a sexually dimorphic Cretaceous crown limulid reveals underestimated horseshoe crab divergence times. ORG DIVERS EVOL 2015. [DOI: 10.1007/s13127-015-0229-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
36
|
Selden PA, Lamsdell JC, Qi L. An unusual euchelicerate linking horseshoe crabs and eurypterids, from the Lower Devonian (Lochkovian) of Yunnan, China. ZOOL SCR 2015. [DOI: 10.1111/zsc.12124] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Paul A. Selden
- Department of Geology; University of Kansas; 1475 Jayhawk Boulevard Lawrence KS 66045 USA
- Natural History Museum; Cromwell Road London SW7 5BD UK
| | - James C. Lamsdell
- Department of Geology and Geophysics; Yale University; PO Box 208109 New Haven CT 06520 USA
| | - Liu Qi
- School of Earth Sciences; China University of Geosciences; Wuhan 430074 Hubei China
| |
Collapse
|
37
|
Siveter DJ, Briggs DEG, Siveter DJ, Sutton MD, Legg D, Joomun S. Enalikter aphson
is an arthropod: a reply to Struck
et al
. (2014). Proc Biol Sci 2015. [PMCID: PMC4375861 DOI: 10.1098/rspb.2014.2663] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
38
|
Garwood RJ, Dunlop J. Three-dimensional reconstruction and the phylogeny of extinct chelicerate orders. PeerJ 2014; 2:e641. [PMID: 25405073 PMCID: PMC4232842 DOI: 10.7717/peerj.641] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/08/2014] [Indexed: 12/12/2022] Open
Abstract
Arachnids are an important group of arthropods. They are: diverse and abundant; a major constituent of many terrestrial ecosystems; and possess a deep and extensive fossil record. In recent years a number of exceptionally preserved arachnid fossils have been investigated using tomography and associated techniques, providing valuable insights into their morphology. Here we use X-ray microtomography to reconstruct members of two extinct arachnid orders. In the Haptopoda, we demonstrate the presence of 'clasp-knife' chelicerae, and our novel redescription of a member of the Phalangiotarbida highlights leg details, but fails to resolve chelicerae in the group due to their small size. As a result of these reconstructions, tomographic studies of three-dimensionally preserved fossils now exist for three of the four extinct orders, and for fossil representatives of several extant ones. Such studies constitute a valuable source of high fidelity data for constructing phylogenies. To illustrate this, here we present a cladistic analysis of the chelicerates to accompany these reconstructions. This is based on a previously published matrix, expanded to include fossil taxa and relevant characters, and allows us to: cladistically place the extinct arachnid orders; explicitly test some earlier hypotheses from the literature; and demonstrate that the addition of fossils to phylogenetic analyses can have broad implications. Phylogenies based on chelicerate morphology-in contrast to molecular studies-have achieved elements of consensus in recent years. Our work suggests that these results are not robust to the addition of novel characters or fossil taxa. Hypotheses surrounding chelicerate phylogeny remain in a state of flux.
Collapse
Affiliation(s)
- Russell J. Garwood
- School of Earth, Atmospheric and Environmental Sciences and The Manchester X-ray Imaging Facility, School of Materials, The University of Manchester, Manchester, UK
| | - Jason Dunlop
- Museum für Naturkunde, Leibniz Institute for Research on Evolution and Biodiversity at the Humboldt University Berlin, Berlin, Germany
| |
Collapse
|
39
|
Legg DA. Sanctacaris uncata: the oldest chelicerate (Arthropoda). Naturwissenschaften 2014; 101:1065-73. [PMID: 25296691 DOI: 10.1007/s00114-014-1245-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/01/2014] [Accepted: 09/19/2014] [Indexed: 12/18/2022]
Abstract
The morphology of the arthropod Sanctacaris uncata, from the Middle Cambrian Burgess Shale of Canada, is reinterpreted based on a restudy of previously described material. Although originally considered a chelicerate-like arthropod, these affinities were dismissed based primarily on interpretations of the anterior appendages and hypotheses which considered the megacheirans ('great-appendage' arthropods) as putative ancestors of chelicerates. The similarities between megacheirans and chelicerates appear to be overstated however, and this study instead reaffirms the identity of putative chelicerate feature in S. uncata and similar arthropods such as Sidneyia and Emeraldella, both also from the Middle Cambrian Burgess Shale. Newly interpreted features, including the presence of pediform exites, multi-partite trunk exopods, and a trunk differentiated into an anterior limb-bearing area and a differentiated posterior limbless abdomen, were coded into an extensive phylogenetic data set of fossil and recent arthropods. In all analyses, Sanctacaris resolved as the basal-most member of total-group Euchelicerata (the least inclusive group including horseshoe crabs and arachnids but not pycnogonids), thus making it the oldest chelicerate in the fossil record. The vicissicaudates (including Sidneyia, Emeraldella, aglaspidids, and cheloniellids--all of which have previously been allied to chelicerates) resolved as sister-taxon to crown-group Chelicerata. This topology indicates that many purported chelicerate features, such as lamellar gills, and a differentiated posterior abdomen evolved sequentially in the chelicerate stem-lineage.
Collapse
Affiliation(s)
- David A Legg
- Oxford University Museum of Natural History, Parks Road, Oxford, OX1 3PW, UK,
| |
Collapse
|
40
|
Kin A, Błażejowski B. The horseshoe crab of the genus Limulus: living fossil or stabilomorph? PLoS One 2014; 9:e108036. [PMID: 25275563 PMCID: PMC4183490 DOI: 10.1371/journal.pone.0108036] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 06/02/2014] [Indexed: 12/02/2022] Open
Abstract
A new horseshoe crab species, Limulus darwini, is described from the uppermost Jurassic (ca. 148 Ma) near-shore sediments of the Kcynia Formation, central Poland. The only extant species Limulus polyphemus (Linnaeus) inhabits brackish-marine, shallow water environments of the east coast of the United States. Here it is shown that there are no important morphological differences between the Kcynia Formation specimens and extant juvenile representatives of the genus Limulus. The palaeoecological setting inhabited by the new species and the trophic relationships of extant horseshoe crabs are discussed in an attempt to determine the potential range of food items ingested by these Mesozoic xiphosurans. In this paper we propose the adoption of a new term stabilomorphism, this being: an effect of a specific formula of adaptative strategy among organisms whose taxonomic status does not exceed genus-level. A high effectiveness of adaptation significantly reduces the need for differentiated phenotypic variants in response to environmental changes and provides for long-term evolutionary success.
Collapse
Affiliation(s)
- Adrian Kin
- Society of Friends of Earth Sciences PHACOPS, Warsaw, Poland
| | | |
Collapse
|
41
|
Sharma PP, Kaluziak ST, Pérez-Porro AR, González VL, Hormiga G, Wheeler WC, Giribet G. Phylogenomic Interrogation of Arachnida Reveals Systemic Conflicts in Phylogenetic Signal. Mol Biol Evol 2014; 31:2963-84. [DOI: 10.1093/molbev/msu235] [Citation(s) in RCA: 215] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
42
|
|
43
|
Lamsdell JC, Selden PA. Babes in the wood--a unique window into sea scorpion ontogeny. BMC Evol Biol 2013; 13:98. [PMID: 23663507 PMCID: PMC3679797 DOI: 10.1186/1471-2148-13-98] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 04/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Few studies on eurypterids have taken into account morphological changes that occur throughout postembryonic development. Here two species of eurypterid are described from the Pragian Beartooth Butte Formation of Cottonwood Canyon in Wyoming and included in a phylogenetic analysis. Both species comprise individuals from a number of instars, and this allows for changes that occur throughout their ontogeny to be documented, and how ontogenetically variable characters can influence phylogenetic analysis to be tested. RESULTS The two species of eurypterid are described as Jaekelopterus howelli (Kjellesvig-Waering and Størmer, 1952) and Strobilopterus proteus sp. nov. Phylogenetic analysis places them within the Pterygotidae and Strobilopteridae respectively, both families within the Eurypterina. Jaekelopterus howelli shows positive allometry of the cheliceral denticles throughout ontogeny, while a number of characteristics including prosomal appendage length, carapace shape, lateral eye position, and relative breadth all vary during the growth of Strobilopterus proteus. CONCLUSIONS The ontogeny of Strobilopterus proteus shares much in common with that of modern xiphosurans, however certain characteristics including apparent true direct development suggest a closer affinity to arachnids. The ontogenetic development of the genital appendage also supports the hypothesis that the structure is homologous to the endopods of the trunk limbs of other arthropods. Including earlier instars in the phylogenetic analysis is shown to destabilise the retrieved topology. Therefore, coding juveniles as individual taxa in an analysis is shown to be actively detrimental and alternative ways of coding ontogenetic data into phylogenetic analyses should be explored.
Collapse
Affiliation(s)
- James C Lamsdell
- Paleontological Institute and Department of Geology, University of Kansas, 1475 Jayhawk Boulevard, Lawrence, KS 66045, USA
| | - Paul A Selden
- Paleontological Institute and Department of Geology, University of Kansas, 1475 Jayhawk Boulevard, Lawrence, KS 66045, USA
- Palaeontology Department, Natural History Museum, Cromwell Road, London SW7, 5BD, UK
| |
Collapse
|