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Yang X, Aguado MT, Yang J, Bleidorn C. A burrowing annelid from the early Cambrian. Biol Lett 2024; 20:20240357. [PMID: 39378985 DOI: 10.1098/rsbl.2024.0357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 08/26/2024] [Accepted: 09/17/2024] [Indexed: 10/10/2024] Open
Abstract
Soft-bodied fossils of annelids from the Cambrian are relatively rare but provide vital insights into the early evolution and diversification of annelids. Here we describe a new annelid, Xiaoshibachaeta biodiversa gen. et sp. nov., from the early Cambrian (Stage 3) Xiaoshiba biota of Kunming, Yunnan Provence, China. This worm is obliquely oriented in the sediment, and is characteristic of a cephalic cage-like structure formed by the anteriorly directed parapodia and long chaetae of chaetiger 1, strongly suggesting an endobenthic lifestyle. This first report of an annelid worm from the Xiaoshiba biota provides the earliest known plausible evidence of burrowing behaviour in Annelida. Phylogenetic analyses recover X. biodiversa in the polytomy with other crown-group Annelida, indicating that the evolution of cephalic cage in Annelida is most likely convergent.
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Affiliation(s)
- Xiaoyu Yang
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming 650500, People's Republic of China
- Animal Evolution and Biodiversity, University of Göttingen, Göttingen 37073, Germany
| | - M Teresa Aguado
- Animal Evolution and Biodiversity, University of Göttingen, Göttingen 37073, Germany
| | - Jie Yang
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming 650500, People's Republic of China
| | - Christoph Bleidorn
- Animal Evolution and Biodiversity, University of Göttingen, Göttingen 37073, Germany
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Yang X, Aguado MT, Helm C, Zhang Z, Bleidorn C. New fossil of Gaoloufangchaeta advances the origin of Errantia (Annelida) to the early Cambrian. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231580. [PMID: 38601033 PMCID: PMC11004674 DOI: 10.1098/rsos.231580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 04/12/2024]
Abstract
Molecular clock estimates suggest the origin of Annelida dates back to the Ediacaran period, which is in discordance with the first appearance of this taxon in the early Cambrian, as evidenced by the fossil records of stem-group and basally branching crown-group annelids. Using new material from the early Cambrian Guanshan biota (Cambrian Series 2, Stage 4), we re-interpret Gaoloufangchaeta bifurcus Zhao, Li & Selden, 2023, as the earliest known errantian annelid. Gaoloufangchaeta has a prominent anterior end bearing three pairs of putatively sensory appendages and a pair of anterior eyes; a muscular eversible pharynx with papillae is identified. The presence of enlarged parapodia with acicula-like structures and long capillary chaetae suggests a pelagic lifestyle for this taxon. Our phylogenetic analyses recover Gaoloufangchaeta within the Phyllodocida (Pleistoannelida, Errantia), extending the origin of Errantia back to the early Cambrian. Our data are in line with the hypothesis that Annelida diverged before the Cambrian and indicate both morphological and ecological diversification of annelids in the early Cambrian.
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Affiliation(s)
- Xiaoyu Yang
- Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming650500, People's Republic of China
- Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, Göttingen37073, Germany
| | - M. Teresa Aguado
- Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, Göttingen37073, Germany
| | - Conrad Helm
- Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, Göttingen37073, Germany
| | - Zhiqian Zhang
- School of Fine Arts, Yunnan Normal University, Kunming650500, People's Republic of China
| | - Christoph Bleidorn
- Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, Göttingen37073, Germany
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Kimmig J, LaVine RJ, Schiffbauer JD, Egenhoff SO, Shelton KL, Leibach WW. Annelids from the Cambrian (Wuliuan Stage, Miaolingian) Spence Shale Lagerstätte of northern Utah, USA. HISTORICAL BIOLOGY 2023; 36:934-943. [PMID: 38800616 PMCID: PMC11114447 DOI: 10.1080/08912963.2023.2196685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/22/2023] [Indexed: 05/29/2024]
Abstract
The Spence Shale Member of the Langston Formation in northern Utah and southern Idaho preserves generally non-biomineralized fossil assemblages referred to as the Spence Shale Lagerstätte. The biota of this Lagerstätte is dominated by panarthropods, both biomineralized and soft-bodied examples, but also preserves diverse infaunal organisms, including species of scalidophorans, echinoderms, lobopodians, stalked filter feeders, and various problematic taxa. To date, however, only a single annelid fossil, originally assigned to Canadia sp., has been described from the Spence Shale. This lone specimen and another recently collected specimen were analyzed in this study using scanning electron microscopy and energy dispersive X-ray spectrometry. The previous occurrence is reassigned to Burgessochaeta cf. B. setigera Walcott, 1911. The new fossil, however, is identified as a novel polychaete taxon, Shaihuludia shurikeni gen. et sp. nov., characterized by the presence of fused, bladed chaetae and a wide body. The occurrence of Burgessochaeta is the first outside the Burgess Shale and its vicinity, whereas Shaihuludia shurikeni gen. et sp. nov. adds to the diversity of annelids in the middle Cambrian and highlights the diversity of the Spence Shale Lagerstätte.
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Affiliation(s)
- Julien Kimmig
- Abteilung Geowissenschaften, Staatliches Museum für Naturkunde Karlsruhe, Karlsruhe, 76133, Germany
- The Harold Hamm School of Geology & Geological Engineering, University of North Dakota, Grand Forks, ND 58202, USA
| | - Rhiannon J. LaVine
- Biodiversity Institute, University of Kansas, Lawrence, Kansas 66045, USA
| | - James D. Schiffbauer
- Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA
- X-ray Microanalysis Laboratory, University of Missouri, Columbia, MO 65211, USA
| | - Sven O. Egenhoff
- The Harold Hamm School of Geology & Geological Engineering, University of North Dakota, Grand Forks, ND 58202, USA
| | - Kevin L. Shelton
- Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Wade W. Leibach
- Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA
- Jacobs Solutions, St. Louis, MO 63102, USA
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Osawa H, Caron JB, Gaines RR. First record of growth patterns in a Cambrian annelid. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221400. [PMID: 37122950 PMCID: PMC10130728 DOI: 10.1098/rsos.221400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 04/03/2023] [Indexed: 05/03/2023]
Abstract
Early annelid evolution is mostly known from 13 described species from Cambrian Burgess Shale-type Lagerstätten. We introduce a new exceptionally well-preserved polychaete, Ursactis comosa gen. et sp. nov., from the Burgess Shale (Wuliuan Stage). This small species (3-15 mm) is the most abundant Cambrian polychaete known to date. Most specimens come from Tokumm Creek, a new Burgess Shale locality in northern Kootenay National Park, British Columbia, Canada. Ursactis has a pair of large palps, thin peristomial neurochaetae and biramous parapodia bearing similarly sized capillary neurochaetae and notochaetae, except for segments six to nine, which also have longer notochaetae. The number of segments in this polychaete range between 8 and 10 with larger individuals having 10 segments. This number of segments in Ursactis is remarkably small compared with other polychaetes, including modern forms. Specimens with 10 segments show significant size variations, and the length of each segment increases with the body length, indicating that body growth was primarily achieved by increasing the size of existing segments rather than adding new ones. This contrasts with most modern polychaetes, which typically have a larger number of segments through additions of segments throughout life. The inferred growth pattern in Ursactis suggests that annelids had evolved control over segment addition by the mid-Cambrian.
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Affiliation(s)
- Hatena Osawa
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
- Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada M5S 2C6
| | - Jean-Bernard Caron
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
- Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada M5S 2C6
- Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario, Canada M5S 3B1
| | - Robert R. Gaines
- Geology Department, Pomona College, 185 E Sixth Street, Claremont, CA 91711, USA
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Zhang Z, Smith MR, Ren X. The Cambrian cirratuliform Iotuba denotes an early annelid radiation. Proc Biol Sci 2023; 290:20222014. [PMID: 36722078 PMCID: PMC9890102 DOI: 10.1098/rspb.2022.2014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The principal animal lineages (phyla) diverged in the Cambrian, but most diversity at lower taxonomic ranks arose more gradually over the subsequent 500 Myr. Annelid worms seem to exemplify this pattern, based on molecular analyses and the fossil record: Cambrian Burgess Shale-type deposits host a single, early-diverging crown-group annelid alongside a morphologically and taxonomically conservative stem group; the polychaete sub-classes diverge in the Ordovician; and many orders and families are first documented in Carboniferous Lagerstätten. Fifteen new fossils of the 'phoronid' Iotuba (=Eophoronis) chengjiangensis from the early Cambrian Chengjiang Lagerstätte challenge this picture. A chaetal cephalic cage surrounds a retractile head with branchial plates, affiliating Iotuba with the derived polychaete families 'Flabelligeridae' and Acrocirridae. Unless this similarity represents profound convergent evolution, this relationship would pull back the origin of the nested crown groups of Cirratuliformia, Sedentaria and Pleistoannelida by tens of millions of years-indicating a dramatic unseen origin of modern annelid diversity in the heat of the Cambrian 'explosion'.
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Affiliation(s)
- ZhiFei Zhang
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments and Department of Geology, Northwest University, Xi'an 710069, People's Republic of China
| | - Martin R. Smith
- Department of Earth Sciences, Durham University, Mountjoy Site, South Road, Durham DH1 3LE, UK
| | - XinYi Ren
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments and Department of Geology, Northwest University, Xi'an 710069, People's Republic of China
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Martynov AV, Korshunova TA. Renewed perspectives on the sedentary-pelagic last common bilaterian ancestor. CONTRIBUTIONS TO ZOOLOGY 2022. [DOI: 10.1163/18759866-bja10034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Various evaluations of the last common bilaterian ancestor (lcba) currently suggest that it resembled either a microscopic, non-segmented motile adult; or, on the contrary, a complex segmented adult motile urbilaterian. These fundamental inconsistencies remain largely unexplained. A majority of multidisciplinary data regarding sedentary adult ancestral bilaterian organization is overlooked. The sedentary-pelagic model is supported now by a number of novel developmental, paleontological and molecular phylogenetic data: (1) data in support of sedentary sponges, in the adult stage, as sister to all other Metazoa; (2) a similarity of molecular developmental pathways in both adults and larvae across sedentary sponges, cnidarians, and bilaterians; (3) a cnidarian-bilaterian relationship, including a unique sharing of a bona fide Hox-gene cluster, of which the evolutionary appearance does not connect directly to a bilaterian motile organization; (4) the presence of sedentary and tube-dwelling representatives of the main bilaterian clades in the early Cambrian; (5) an absence of definite taxonomic attribution of Ediacaran taxa reconstructed as motile to any true bilaterian phyla; (6) a similarity of tube morphology (and the clear presence of a protoconch-like apical structure of the Ediacaran sedentary Cloudinidae) among shells of the early Cambrian, and later true bilaterians, such as semi-sedentary hyoliths and motile molluscs; (7) recent data that provide growing evidence for a complex urbilaterian, despite a continuous molecular phylogenetic controversy. The present review compares the main existing models and reconciles the sedentary model of an urbilaterian and the model of a larva-like lcba with a unified sedentary(adult)-pelagic(larva) model of the lcba.
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Affiliation(s)
- Alexander V. Martynov
- Zoological Museum, Moscow State University, Bolshaya Nikitskaya Str. 6, 125009 Moscow, Russia,
| | - Tatiana A. Korshunova
- Koltzov Institute of Developmental Biology RAS, 26 Vavilova Str., 119334 Moscow, Russia
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A Cambrian crown annelid reconciles phylogenomics and the fossil record. Nature 2020; 583:249-252. [PMID: 32528177 DOI: 10.1038/s41586-020-2384-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/26/2020] [Indexed: 11/09/2022]
Abstract
The phylum of annelids is one of the most disparate animal phyla and encompasses ambush predators, suspension feeders and terrestrial earthworms1. The early evolution of annelids remains obscure or controversial2,3, partly owing to discordance between molecular phylogenies and fossils2,4. Annelid fossils from the Cambrian period have morphologies that indicate epibenthic lifestyles, whereas phylogenomics recovers sessile, infaunal and tubicolous taxa as an early diverging grade5. Magelonidae and Oweniidae (Palaeoannelida1) are the sister group of all other annelids but contrast with Cambrian taxa in both lifestyle and gross morphology2,6. Here we describe a new fossil polychaete (bristle worm) from the early Cambrian Canglangpu formation7 that we name Dannychaeta tucolus, which is preserved within delicate, dwelling tubes that were originally organic. The head has a well-defined spade-shaped prostomium with elongated ventrolateral palps. The body has a wide, stout thorax and elongated abdomen with biramous parapodia with parapodial lamellae. This character combination is shared with extant Magelonidae, and phylogenetic analyses recover Dannychaeta within Palaeoannelida. To our knowledge, Dannychaeta is the oldest polychaete that unambiguously belongs to crown annelids, providing a constraint on the tempo of annelid evolution and revealing unrecognized ecological and morphological diversity in ancient annelids.
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Parry L, Caron JB. Canadia spinosa and the early evolution of the annelid nervous system. SCIENCE ADVANCES 2019; 5:eaax5858. [PMID: 31535028 PMCID: PMC6739095 DOI: 10.1126/sciadv.aax5858] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 08/09/2019] [Indexed: 05/19/2023]
Abstract
Annelid worms are a disparate, primitively segmented clade of bilaterians that first appear during the early Cambrian Period. Reconstructing their early evolution is complicated by the extreme morphological diversity in early diverging lineages, rapid diversification, and sparse fossil record. Canadia spinosa, a Burgess Shale fossil polychaete, is redescribed as having palps with feeding grooves, a dorsal median antenna and biramous parapodia associated with the head and flanking a ventral mouth. Carbonaceously preserved features are identified as a terminal brain, circumoral connectives, a midventral ganglionated nerve cord and prominent parapodial nerves. Phylogenetic analysis recovers neuroanatomically simple extant taxa as the sister group of other annelids, but the phylogenetic position of Canadia suggests that the annelid ancestor was reasonably complex neuroanatomically and that reduction of the nervous system occurred several times independently in the subsequent 500 million years of annelid evolution.
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Affiliation(s)
- Luke Parry
- Department of Natural History, Palaeobiology, Royal Ontario Museum, 100 Queen’s Park, Toronto, Ontario M5S 2C6, Canada
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
- Corresponding author.
| | - Jean-Bernard Caron
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
- Department of Earth Sciences, University of Toronto, Toronto, Ontario M5S 3B1, Canada
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