Papers in Palaeontology最新文献

{"title":"Late Ordovician and early Silurian virgianid and stricklandioid brachiopods from North Greenland: implications for a warm-water faunal province","authors":"Jisuo Jin, Christian M. Ø. Rasmussen, Peter M. Sheehan, David A. T. Harper","doi":"10.1002/spp2.1544","DOIUrl":"https://doi.org/10.1002/spp2.1544","url":null,"abstract":"An unusually rich and diverse suite of virgianid brachiopods, hitherto poorly known, is systematically described here for the first time from the Ordovician–Silurian boundary interval (late Katian – Aeronian) of North Greenland. The Late Ordovician virgianids comprise typical taxa of the warm-water <i>Tcherskidium</i> fauna (e.g. <i>Tcherskidium tenuicostatum</i>, <i>Proconchidium schleyi</i>, <i>Holorhynchus giganteus</i> and <i>Deloprosopus dawesi</i> sp. nov.). Among the early Silurian taxa, <i>Virgiana hursti</i> sp. nov. occurs as abundant shell beds, similar to other congeneric species in Laurentia, but has somewhat larger internal skeletal structures, albeit not as extravagantly developed as in the late Katian virgianids; <i>Borealoides balderi</i> gen. et sp. nov. shows extreme thickening of the shell wall and internal structures, approaching the extravagant calcification of Katian virgianids. The highly distinctive mid-Aeronian stricklandioid brachiopod genus, <i>Kulumbella</i>, characterized by a shell with criss-cross (divaricate) ribbing, also occurs in North Greenland, represented by <i>K</i>. <i>heimdali</i> sp. nov., which has the largest and most strongly biconvex shells for the genus. Palaeogeographically, the Late Ordovician virgianid fauna of Laurentia was highly distinct, confined to the low–mid tropical latitudes north of the palaeoequator. In comparison, the early Silurian (Rhuddanian) <i>Virgiana</i> and some related taxa in Laurentia spanned the tropics of both hemispheres, forming extensive shell beds in carbonate basins, although <i>Borealis</i> and <i>Borealoides</i> gen. nov. remained confined largely to the northern hemisphere, suggesting a certain level of provincialism extending into the earliest Silurian. A palaeoecological preference for warm-water carbonate settings would explain the unusual abundance and richness of the virgianid faunas in North Greenland.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"31 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139560763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Archaeichnium haughtoni: a robust burrow lining from the Ediacaran–Cambrian transition of Namibia","authors":"Katherine A. Turk, Mikaela A. Pulsipher, Eugene Bergh, Marc Laflamme, Simon A. F. Darroch","doi":"10.1002/spp2.1546","DOIUrl":"https://doi.org/10.1002/spp2.1546","url":null,"abstract":"Following various assignments to Archaeocyatha, worm tubes, and finally <i>incertae sedis</i>, the enigmatic Ediacaran–Cambrian taxon <i>Archaeichnium haughtoni</i> has in recent years come to represent somewhat of a wastebasket taxon to which the indeterminate tapering tubular forms common across this interval are assigned. This ‘catch-all’ status has been aided in part by both suboptimal specimen photography and the temporary loss of the holotype after its second redescription in 1978. Recent rediscovery of the <i>A. haughtoni</i> holotype in the collections of the Iziko South African Museum in Cape Town has enabled a much-needed re-assessment of this critical and cryptic taxon, with results suggesting that this material from the latest Ediacaran or earliest Cambrian of Namibia is among the earliest fossil record examples of marine worm burrow linings, and the oldest examples of linings robust enough to withstand exhumation and current transport. These traces indicate the emergence of this important animalian ecosystem engineering behaviour closer to the Ediacaran–Cambrian boundary than previously thought.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"31 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139560764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new early water frog (Telmatobius) from the Miocene of the Bolivian Altiplano","authors":"Raúl O. Gómez, Tomás Ventura, Guillermo F. Turazzini, Laurent Marivaux, Rubén Andrade Flores, Alberto Boscaini, Marcos Fernández-Monescillo, Bernardino Mamani Quispe, Mercedes B. Prámparo, Séverine Fauquette, Céline Martin, Philippe Münch, François Pujos, Pierre-Olivier Antoine","doi":"10.1002/spp2.1543","DOIUrl":"https://doi.org/10.1002/spp2.1543","url":null,"abstract":"We describe the new frog <i>Telmatobius achachila</i> sp. nov. from the late Middle to earliest Late Miocene of Achiri, based on a partial skeleton found at 3960 m above sealevel in the Bolivian Altiplano. This skeleton, attributed to a male adult, constitutes the first documented fossil record of the speciose living genus <i>Telmatobius</i>, endemic to the Andean Cordillera and the Altiplano. Phylogenetic analysis confirms the new species as being part of the crown group, and diverging both later than the <i>T. verrucosus</i> group and earlier than the <i>T. bolivianus</i>, <i>T. marmoratus</i> and <i>T. macrostomus</i> groups. Coupled with its accurate stratigraphic provenance and age, this phylogenetic position provides a relevant calibration point for timing the evolutionary history of these highland, mostly aquatic frogs. The skeleton of <i>T. achachila</i> indicates that several of the osteological peculiarities of extant <i>Telmatobius</i> were already acquired at <i>c</i>. 12 Ma, including some that might be linked to their aquatic lifestyle. Together with mixed montane–rainforest pollen vegetation uncovered in the same level, this fossil specimen further provides key data enabling a more accurate reconstruction of ancestral habitats and elevation ranges of <i>Telmatobius</i>, agreeing with the previously postulated conditions in which these water frogs might have first evolved. Ultimately, this discovery adds to the sparse evidence of a humid tropical Bolivian Altiplano just prior to: (1) the Late Miocene uplift pulse of the Central Altiplano; and (2) the drastic climate deterioration that occurred from Late Miocene time onward, leading to the harsh highland-steppe environments reigning there today.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139482543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Macroflora from Lower Jurassic (Pliensbachian) of Hicks Creek, southern Talkeetna Mountains, south-central Alaska","authors":"Maria Barbacka, Artur Górecki, Christian Pott, Jadwiga Ziaja, Robert B. Blodgett, Curvin Metzler, Andrew H. Caruthers, Geethanalje Edirisooriya, Grzegorz Pacyna","doi":"10.1002/spp2.1541","DOIUrl":"https://doi.org/10.1002/spp2.1541","url":null,"abstract":"A recently discovered Early Jurassic locality at Hicks Creek, Talkeetna Mountains, Alaska, yielded a macrofossil plant assemblage comprising predominantly bennettitaleans and ferns, accompanied by horsetails, seed ferns, cycads and conifers. Single species from different plant groups dominate the assemblage (e.g. <i>Cladophlebis alata</i>, <i>Otozamites pterophylloides</i>; less frequent <i>Rhaphidopteris</i> sp. and <i>Pagiophyllum falcatum</i>; sporadic <i>Thallites</i> sp., <i>Klukia</i> sp., <i>Todites williamsonii</i>, <i>Coniopteris bella</i>, <i>Sagenopteris</i> sp., <i>Zamites</i> sp., <i>Nilssoniopteris pristis</i>, <i>Pseudoctenis</i> sp., <i>Eretmophyllum</i> sp. and <i>Elatides</i> sp.). We also encountered a new foliage of cycadophyte type, <i>Hanophyllum varioserratum</i> gen. et sp. nov. Hicks Creek is one of four Alaskan areas with fossil Mesozoic plants that have been investigated. Along with rocks of Puale Bay and the East Fork of Boulder Creek exposures, this locality is of Early Jurassic age, while Cape Lisburne is Early Cretaceous (Albian). Based on a comparison of the floral composition of Hicks Creek with some other localities (Alaska and beyond), environmental conditions for the Peninsular terrane are inferred. Floristic differences between localities are explained by the varied topography, interpreted as disturbed coastal–lagoonal or as undisturbed, moist and warm inland. Some taxa (<i>Todites williamsonii</i>, <i>Coniopteris bella</i>, <i>Nilssoniopteris pristis</i>, <i>Otozamites tenuatus</i>, <i>O</i>. <i>mimetes</i>, <i>Brachyphyllum crucis</i>) common to the Alaska Peninsula and Middle Jurassic of Yorkshire may suggest a possible pathway of plant migration during the movement of the Peninsular terrane. The occurrence of <i>Cladophlebis alata</i> in the Lower Jurassic of south-central Alaska and the Lower Cretaceous of northwestern Alaska may also shed light on the posited spread of this species.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"59 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139056091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early eukaryotic microfossils of the late Palaeoproterozoic Limbunya Group, Birrindudu Basin, northern Australia","authors":"Leigh Anne Riedman, Susannah M. Porter, Maxwell A. Lechte, Angelo dos Santos, Galen P. Halverson","doi":"10.1002/spp2.1538","DOIUrl":"https://doi.org/10.1002/spp2.1538","url":null,"abstract":"Fine-grained, siliciclastic units of the &gt;1642 ± 3.9 Ma late Palaeoproterozoic Limbunya Group, Birrindudu Basin host rich, well-preserved organic-walled microfossil assemblages that include members of total-group eukaryotes. These assemblages include taxa characteristic of this interval such as <i>Tappania plana</i> and <i>Satka favosa</i>, as well as less common taxa such as <i>Gigantosphaeridium fibratum</i>, <i>Gigantosphaeridium floccosum</i>, <i>Kamolineata elongata</i> (= <i>Valeria elongata</i>; new combination), and four new species. The new taxa include <i>Limbunyasphaera operculata</i> gen et sp. nov., the oldest known operculate taxon; the large septate filaments of <i>Siphonoseptum bombycinum</i> gen. et sp. nov.; the platy tubular form <i>Birrindudutuba brigandinia</i> gen. et sp. nov.; and <i>Filinexum torsivum</i> gen. et sp. nov., which bears a spirally twisted wall constructed of bound fibres. Our data show that eukaryotic fossils are particularly abundant in marginal marine environments such as tidal flats and back-barrier lagoonal settings. This is exemplified by the Blue Hole Formation, which features an especially diverse and complex assemblage. We also present a new within-formation eukaryotic species richness estimate for the Palaeoproterozoic to Tonian. This estimate indicates that the oldest eukaryote-bearing units already show species richness levels similar to those of the much younger and more heavily sampled Tonian period. Additionally, these oldest eukaryotic assemblages show significant morphological disparity, particularly in vesicle construction. These high levels of eukaryotic species richness and morphological disparity suggest that although late Palaeoproterozoic units preserve our oldest record of eukaryotes, the eukaryotic clade has a much deeper history.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"26 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139056097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Eocene–Miocene anuran fossils from Peruvian Amazonia: insights into neotropical frog evolution and diversity","authors":"Olivier Jansen, Raúl Orencio Gómez, Antoine Fouquet, Laurent Marivaux, Rodolfo Salas-Gismondi, Pierre-Olivier Antoine","doi":"10.1002/spp2.1542","DOIUrl":"https://doi.org/10.1002/spp2.1542","url":null,"abstract":"Anurans are one of the most diverse vertebrate groups, particularly in Amazonia, where species richness exceeds that of anywhere else. Amazonian frogs belong to three main lineages (Hyloidea, Microhylidae and Pipidae), each of which diversified during the Cenozoic. However, due to the virtual absence of an anuran fossil record in that area, the evolutionary history of modern lineages has so far remained accessible only via molecular data. In recent decades, a series of field campaigns in Peruvian Amazonia led to the discovery of an unparalleled set of anuran bone fragments, scattered across different sites spanning the Eocene–Miocene time interval. Here, we describe these first Palaeogene and early Neogene anurans from Peru with a focus on humeral and ilial morphology, identifying five humeral and five ilial morphotypes. Humeral morphotypes suggest the presence of different lineages of Brachycephaloidea in Peruvian fossil assemblages, whereas ilial morphotypes suggest the presence of Leptodactylidae, although leptodactylid-like ilia also occur in some extant brachycephaloids. Pipids were also identified based on both humeral and ilial fragments. This study fills a major temporal and geographical gap in the evolutionary history of South American anurans, while further uncovering a lack of knowledge in the skeletal morphology of extant anuran families, as well as their inter- and intra-species variability.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"238 1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138823611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Redefining the Huayquerian Stage (Upper Miocene to Lower Pliocene) of the South American chronostratigraphic scale based on biostratigraphical analyses and geochronological dating","authors":"Cristo O. Romano, Alberto C. Garrido, David L. Barbeau, Rocío B. Vera, Ricardo Bonini, Alberto Boscaini, Esperanza Cerdeño, Laura E. Cruz, Graciela I. Esteban, Marcelo S. de la Fuente, Marcos Fernández-Monescillo, Juan C. Fernicola, Verónica Krapovickas, M. Carolina Madozzo-Jaén, M. Encarnación Pérez, François Pujos, Luciano Rasia, Guillermo F. Turazzini, Bárbara Vera, Ross D. E. MacPhee, Analía M. Forasiepi, Francisco J. Prevosti","doi":"10.1002/spp2.1539","DOIUrl":"https://doi.org/10.1002/spp2.1539","url":null,"abstract":"The Huayquerian Stage of the South American chronostratigraphic scheme (named for the Huayquerías del Este, Argentina) was originally based on a poorly known mammal association of six taxa from the Huayquerías Formation. We studied the geology, age and fauna of the Neogene sequence in this area, including the Huayquerías, Tunuyán and Bajada Grande formations. The sequence comprises a monotonous succession of synorogenic epiclastic sediments deposited under arid to semi-arid conditions. Zircon U–Pb dates from 10 tuffaceous levels (7.2–1.6 Ma) place deposition of the Huayquerías Formation during the late Tortonian or Messinian to early Zanclean, the Tunuyán Formation during the Zanclean–Piacenzian, and the Bajada Grande Formation during the Piacenzian–Calabrian. We present 43 and 31 new mammal taxon records for the Huayquerías and Tunuyán formations, respectively. Progressive faunal change was observed along the sequence. The first records of the Chaco tortoise <i>Chelonoidis chilensis</i> and the notoungulate <i>Xotodon major</i>, and the latest records of Interatheriidae and <i>Typotheriopsis</i> (notoungulates), <i>Metacaremys calfucalel</i>, <i>Phtoramys hidalguense</i> and <i>Lagostomus pretrichodactyla</i> (rodents), <i>Chasicotatus ameghinoi</i> and <i>Macroeuphractus morenoi</i> (xenarthrans) are reported. The faunal associations of the Huayquerías and lower Tunuyán formations are highly similar to each other, and to other coeval localities in Argentina. The <i>Macroeuphractus morenoi</i> Assemblage Biozone is proposed as the basis for redefining the Huayquerian Stage, due to the co-occurrence of three taxa with wide geographical distribution in southern South America: <i>Macroeuphractus morenoi</i>, <i>Pseudotypotherium subinsigne</i> and <i>Lagostomus pretrichodactyla</i>. The age of this biozone is constrained at <i>c.</i> 8–5 Ma in its type area.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"58 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138823804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence for the evolutionary history and diversity of fossil sweetgums: leaves and associated capitate reproductive structures of Liquidambar from the Eocene of Hainan Island, South China","authors":"Natalia P. Maslova, Tatiana M. Kodrul, Vasilisa V. Kachkina, Christa-Charlotte Hofmann, Sheng-Lan Xu, Xiao-Yan Liu, Jian-Hua Jin","doi":"10.1002/spp2.1540","DOIUrl":"https://doi.org/10.1002/spp2.1540","url":null,"abstract":"Extant species of <i>Liquidambar</i> L. exhibit a disjunct distribution between western and eastern Asia and eastern North America to Central America, with the highest species diversity being in China. In this study, two new species of <i>Liquidambar</i> are described from the Eocene of Hainan Island, South China: <i>L. hainanensis</i> on basis of the leaf fossils, and <i>L. ovoidea</i> based on compressions of infructescences. The co-occurrences of <i>L. hainanensis</i> leaves, associated infructescences of <i>L. ovoidea</i> and dispersed pantoporate pollen grains have the combination of morphological features peculiar to the genera <i>Liquidambar</i> and former <i>Semiliquidambar</i> and <i>Altingia</i>. This is considered further palaeobotanical justification for the placement of these three genera into a single genus, <i>Liquidambar</i>, proposed earlier based on molecular markers. Our data provide evidence for the occurrence of an ancestral polymorphic group of <i>Liquidambar</i> species (<i>L. maomingensis</i> with associated capitate infructescences, <i>L. bella</i>, <i>L. hainanensis</i> and <i>L. ovoidea</i>) during the Eocene in South China, and corroborate the view that South China could have been a centre of <i>Liquidambar</i> speciation during the Eocene. The morphological similarity of <i>L. hainanensis</i> leaves to those of the extant species <i>L. orientalis</i> from Western Asia and the North American <i>L. styraciflua</i> may support the importance of both the North Atlantic Land Bridge and the Bering Land Bridge for the dispersal of <i>Liquidambar</i>. Analysis of fossil species of <i>Liquidambar</i> from eastern Asia also contributes to further understanding of patterns in the taxonomic diversity and evolutionary history of this genus.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"47 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138690850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A unique Late Cretaceous fossil wood assemblage from Chilean Patagonia provides clues to a high-latitude continental environment","authors":"Leandro C. A. Martínez, Marcelo Leppe, Leslie M. E. Manríquez, Juan Pablo Pino, Cristine Trevisan, Joseline Manfroi, Héctor Mansilla","doi":"10.1002/spp2.1536","DOIUrl":"https://doi.org/10.1002/spp2.1536","url":null,"abstract":"Fossil plants, including large trunks, stems, some branches, and twigs, were collected from the Maastrichtian (68.9 Ma), upper Dorotea Formation in the Magallanes–Austral Basin, 16 km north of the Cerro Guido–Las Chinas complex in the southern Chilean Magallanes region. These fossil trunks range from 0.2 to 2.2 m in length. Petrographic slides were made in three sections (transverse, radial and tangential) and analysed under a light microscope to study the permineralized fossils. The woods and stems belong to <i>Austroginkgoxylon</i> gen. et sp. nov., <i>Agathoxylon antarcticum</i>, <i>Podocarpoxylon paradoxi</i> sp. nov., <i>Podocarpoxylon mazzonii</i>, <i>Palmoxylon subantarcticae</i> and <i>Notomalvaceoxylon magallanense</i> gen. et sp. nov. The growth rings of gymnosperms and anatomical characters of angiosperms were analysed to obtain palaeoecological data. Interactions between gymnosperm roots growing into the secondary xylem of an angiosperm (nurse logs) are recorded. The data obtained from the fossil woods suggest warm and humid conditions in this southern South American locality during the Late Cretaceous, providing a unique opportunity to study continental environments at high southern latitudes, which are poorly represented on a global scale.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"36 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138690783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An enigmatic structure in the tail of vetulicolians from the Cambrian Chengjiang biota, South China","authors":"Yang Yang, Bi’ang Su, Qiang Ou, Meirong Cheng, Jian Han, Degan Shu","doi":"10.1002/spp2.1537","DOIUrl":"https://doi.org/10.1002/spp2.1537","url":null,"abstract":"Cambrian vetulicolians have mosaic characteristics of both deuterostomes and protostomes, which has important implications for the origin and early evolution of the Deuterostomia. They are intriguing in their bizarre body plan with a series of pharyngeal gill slits. The anterior section is characterized by five pairs of gill pouches, while the paddle-like posterior part is composed of seven or more segments. Although the overall external morphology and some internal anatomies of vetulicolians, such as pharyngeal cavity, gill system and alimentary canal, have largely been clarified, mysteries remain regarding some other internal structures, and their functional interpretations are highly controversial. In this study we identify an important but hitherto unrecognized feature: a sub-rounded, wrinkled structure located ventrally at the posterior section (or ‘tail’) of weakly sclerotized members of vetulicolians, including <i>Xidazoon stephanus</i> and <i>Didazoon haoae</i>, from the early Cambrian Chengjiang biota. The enigmatic structure consistently appears at or between the third and fourth segments of the posterior section. We show that the new structure is an internal organ in the body cavity of vetulicolians and infer that it might have functioned for reproduction, excretion or digestion. The finding of this enigmatic structure from <i>X. stephanus</i> and <i>D</i>. <i>haoae</i> enriches our understanding of vetulicolians and might facilitate further exploration of the anatomy and physiology of early deuterostomes.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"75 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}