Papers in Palaeontology最新文献_第6页

Evaluating growth in Macrospondylus bollensis (Crocodylomorpha, Teleosauroidea) in the Toarcian Posidonia Shale, Germany 评价德国Toarcian Posidonia页岩中bollensis (Crocodylomorpha, teleosauroroidea)的生长

2区地球科学

Papers in Palaeontology Pub Date : 2023-09-01 DOI: 10.1002/spp2.1529

Michela M. Johnson, Eli Amson, Erin E. Maxwell

{"title":"Evaluating growth in Macrospondylus bollensis (Crocodylomorpha, Teleosauroidea) in the Toarcian Posidonia Shale, Germany","authors":"Michela M. Johnson, Eli Amson, Erin E. Maxwell","doi":"10.1002/spp2.1529","DOIUrl":"https://doi.org/10.1002/spp2.1529","url":null,"abstract":"Abstract The study of how organisms grow is a fundamental aspect of palaeontology. Growth in teleosauroids is poorly understood and little studied, especially in an ontogenetic sense. We investigate growth rates of the most common and abundant teleosauroid, Macrospondylus bollensis , in which a large sample of multiple body sizes is available from the Posidonienschiefer Formation (Posidonia Shale) of southwestern Germany. We perform linear regression analyses on 62 specimens of Macrospondylus (16 juveniles, 7 subadults and 39 adults) using 21 cranial and postcranial measurements. Our results show that juvenile, subadult and adult individuals have near‐isometric or isometric growth throughout much of the body. Notably, we find that in Macrospondylus : (1) the femur grows at a faster rate than the skull and hindlimb zeugopodium; (2) the forelimb and hindlimb grow at the same rate; and (3) there is distinct ontogenetic signal in the growth of the orbit and supratemporal fenestra. We also find that limb scaling in Macrospondylus is somewhat comparable to that seen in the extant gavialids Gavialis gangeticus and Tomistoma schlegelii . Last, we examine evolutionary allometry in skull length relative to body size in Crocodylomorpha using femoral length as a proxy, which shows a near‐isometric trend. Non‐thalattosuchian crocodylomorphs (with the exception of one pholidosaurid and one dryosaurid taxon) are differentiated from thalattosuchians due to their shorter skulls, as previously suggested, but the scaling relationship with femur length remains unchanged.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135687701","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}

引用次数: 0

A micromorphological analysis of Bolonia lata Meunier from the Cretaceous of the Neuquén Basin (Patagonia, Argentina): new insights into the tracemaker 阿根廷巴塔哥尼亚地区neuqu<s:1>盆地白垩纪Bolonia lata Meunier的微形态分析:对示踪者的新认识

IF 2.3 2区地球科学

Papers in Palaeontology Pub Date : 2023-09-01 DOI: 10.1002/spp2.1522

Luciana M. Giachetti, D. E. Fernández, M. Comerio, C. Gutiérrez, P. Pazos

{"title":"A micromorphological analysis of Bolonia lata Meunier from the Cretaceous of the Neuquén Basin (Patagonia, Argentina): new insights into the tracemaker","authors":"Luciana M. Giachetti, D. E. Fernández, M. Comerio, C. Gutiérrez, P. Pazos","doi":"10.1002/spp2.1522","DOIUrl":"https://doi.org/10.1002/spp2.1522","url":null,"abstract":"Polychaetes, echinoids and gastropods have been proposed as tracemakers for Bolonia Meunier, an elongate positive epirelief trace fossil characterized by two lobes composed of biserial, subtriangular pads and a mostly heart‐shaped cross‐section. Here, the internal structure and micromorphology of Bolonia are described for the first time using serial thin sections from shallow‐marine Lower Cretaceous intervals of the Agrio Formation (Neuquén Basin, Argentina). In vertical thin sections, a conical structure of variable width extends centrally from the base to the top of the trace. In horizontal thin sections, grains are reoriented and reworked, forming a central zigzag structure. The organic matter and clays form grain aggregates representing the internal structure of individual pads of the trace fossil. The sediment has mostly been reoriented, with grains making up subcircular pods. We interpret the central conical structure as the collapse of the medial zone of the trace fossil, which could have destroyed drain tubes, especially in the absence of early cementation. Studying horizontal thin sections, we reconstruct the diagnostic biserial pads as biserial concave structures. These are interpreted as backfilling structures produced by the aboral and lateral spines of irregular echinoids, which worked together to compact the sediment anteroposteriorly and moved alternatively, explaining the zigzag pattern in the menisci. We propose Spatangoidea or Cassiduloidea (or a closely related group) with a similar burrowing ability and spine movement as tracemakers of these Bolonia specimens.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"118 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74887786","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}

引用次数: 0

Evolutionary process of extremely twisted heteromorph ammonites from the Upper Cretaceous of Japan 日本上白垩纪极扭异形菊石的演化过程

2区地球科学

Papers in Palaeontology Pub Date : 2023-09-01 DOI: 10.1002/spp2.1525

Akihiro Misaki, Takashi Okamoto, Haruyoshi Maeda

{"title":"Evolutionary process of extremely twisted heteromorph ammonites from the Upper Cretaceous of Japan","authors":"Akihiro Misaki, Takashi Okamoto, Haruyoshi Maeda","doi":"10.1002/spp2.1525","DOIUrl":"https://doi.org/10.1002/spp2.1525","url":null,"abstract":"Abstract The heteromorph ammonite Pravitoceras sigmoidale with extremely twisted retroversal hook and its probable ancestors, Didymoceras awajiense and D . morozumii , occur mainly in the Upper Cretaceous Izumi and Sotoizumi groups in southwest Japan. Their morphological characteristics were investigated in this study. Morphotypes I–II were recognized in D. morozumii . Morphotypes III–V were recognized in D. awajiense . Morphotypes VI–VIII were recognized in P. sigmoidale . Moreover, all morphotypes were recognized in both the dextral and sinistral forms of these three species. Based on the morphological and stratigraphic relationships, it is considered that the evolutionary process of these species is divided into three steps: (1) shift from morphotypes I–II to III; (2) increase in variation from morphotypes III to III–V; and (3) shift from morphotypes III–V to VI–VIII. By comparing these morphotypes based on the ‘growing tube model’ belonging to the moving frame analysis, it is seen that there are no significant gaps of coiling patterns in the evolutionary processes of this lineage. Meanwhile, morphotypes III–V of D. awajiense have a larger morphological variation than morphotypes I–II of D . morozumii and morphotypes VI–VIII of P. sigmoidale . These results, and the radiometric ages from previous studies, suggest that D. awajiense , with considerable variation between ancestor and descendant species, existed in a short interval. It seems that P. sigmoidale occurred after the continuous but rapid and drastic morphological evolution from D. morozumii via D. awajiense .","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134916547","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}

引用次数: 0

A review of the glacial environment arthropod trace fossils Umfolozia and Warvichnium with the description of new ichnotaxa 冰期环境节肢动物足迹化石Umfolozia和Warvichnium的综述及新技术分类群的描述

2区地球科学

Papers in Palaeontology Pub Date : 2023-09-01 DOI: 10.1002/spp2.1526

Gabriel E. B. de Barros, Bernardo de C. P. e M. Peixoto, João H. D. Lima, Nicholas J. Minter, Daniel Sedorko

{"title":"A review of the glacial environment arthropod trace fossils Umfolozia and Warvichnium with the description of new ichnotaxa","authors":"Gabriel E. B. de Barros, Bernardo de C. P. e M. Peixoto, João H. D. Lima, Nicholas J. Minter, Daniel Sedorko","doi":"10.1002/spp2.1526","DOIUrl":"https://doi.org/10.1002/spp2.1526","url":null,"abstract":"Abstract Trace fossils are important records of the presence and behaviour of animals in the past, especially in deposits where few body fossils are preserved. They tend to provide the main palaeobiological record for past glacial environments, and are thus very important for understanding the ecology of these palaeoenvironments. Two ichnogenera are common in glacial sediments: Umfolozia and Warvichnium . Both Umfolozia and Warvichnium are attributed to arthropods; the former occurs across the Late Palaeozoic Ice Age (LPIA) and the latter occurs during both the LPIA and the Quaternary glacial event. Here, we review the stratigraphic record, ichnotaxonomy, palaeoecology, palaeoenvironments and possible tracemakers of these two ichnogenera. In addition to assessing morphological ichnotaxobases, we use multivariate morphometric analysis and inferential statistical tests to support our ichnotaxonomic revisions. The diagnosis of Umfolozia is revised, with the description of a new ichnospecies, Umfolozia terere , and the emendation of Umfolozia riojana (formerly Umfolozia longula ). We revised Warvichnium , maintaining the original Warvichnium ulbrichi and allocating two morphologies to the ichnogenus Irichnus : Irichnus saltatorius and I. paripinnatus isp. nov. These trace fossils record several behaviours, and have implications for palaeoenvironmental interpretations and the evolution of invertebrate ecosystems. Using Umfolozia and Warvichnium as case studies, we demonstrate the application of morphometric analysis in ichnotaxonomy and highlight this as a tool that may be applied to other trace‐fossil groups.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"307 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135347038","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}

引用次数: 0

Trilobites of Thailand's Cambrian–Ordovician Tarutao Group and their geological setting 泰国寒武-奥陶系Tarutao群三叶虫及其地质环境

2区地球科学

Papers in Palaeontology Pub Date : 2023-09-01 DOI: 10.1002/spp2.1516

Shelly J. Wernette, Nigel C. Hughes, Paul M. Myrow, Apsorn Sardsud

{"title":"Trilobites of Thailand's Cambrian–Ordovician Tarutao Group and their geological setting","authors":"Shelly J. Wernette, Nigel C. Hughes, Paul M. Myrow, Apsorn Sardsud","doi":"10.1002/spp2.1516","DOIUrl":"https://doi.org/10.1002/spp2.1516","url":null,"abstract":"Abstract Tuff‐bearing upper Cambrian to lowermost Ordovician strata on Ko Tarutao island, Satun province, southernmost peninsular Thailand, contain a rich trilobite fauna relevant to global biostratigraphy, peri‐Gondwanan palaeogeography and shifting evolutionary mode. This area of Sibumasu, a lower Palaeozoic marginal Gondwanan terrane, is shown to have been closely associated with Australia, North China (Sino‐Korea) and other continental fragments from the supercontinent's northern equatorial sector, including South China at that time. Shared faunas also suggest a Kazakhstani and Laurentian association. Collections from eight sections yielded 10 newly discovered species and one new genus from ancient shoreface and inner shelf siliciclastic deposits. With the new taxa and revision of taxa known previously, we refine the age of the upper two formations of the Tarutao Group to the middle of Cambrian Stage 10, and lower–middle Tremadocian. Two biozones are erected for Sibumasu: the Eosaukia buravasi Zone, encompassing all Cambrian sections from Ko Tarutao, and the Asaphellus charoenmiti Zone, encompassing the Tremadocian fauna discussed herein. The new genus is Tarutaoia and new species are Tsinania sirindhornae , Pseudokoldinioidia maneekuti , Pagodia ? uhleini , Asaphellus charoenmiti , Tarutaoia techawani , Jiia talowaois , Caznaia imsamuti , Anderssonella undulata , Lophosaukia nuchanongi and Corbinia perforata . Other taxa reported for the first time from Tarutao are Mansuyia ? sp., Parakoldinioidia callosa Qian, Pseudagnostus sp., Homagnostus sp., Haniwa mucronata Shergold, Haniwa sosanensis ? Kobayashi, Lichengia simplex Shergold, Pacootasaukia sp., Wuhuia ? sp., Plethopeltella sp., Apatokephalus sp., Akoldinioidia sp. 1 and Koldinioidia sp.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135641223","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}

引用次数: 0

The last Baru (Crocodylia, Mekosuchinae): a new species of ‘cleaver‐headed crocodile’ from central Australia and the turnover of crocodylians during the Late Miocene in Australia 最后的巴鲁鳄(鳄鱼科，鳄鱼科):一种来自澳大利亚中部的“切头鳄”新种和澳大利亚中新世晚期鳄鱼的更替

2区地球科学

Papers in Palaeontology Pub Date : 2023-09-01 DOI: 10.1002/spp2.1523

Adam M. Yates, Jorgo Ristevski, Steven W. Salisbury

{"title":"The last Baru (Crocodylia, Mekosuchinae): a new species of ‘cleaver‐headed crocodile’ from central Australia and the turnover of crocodylians during the Late Miocene in Australia","authors":"Adam M. Yates, Jorgo Ristevski, Steven W. Salisbury","doi":"10.1002/spp2.1523","DOIUrl":"https://doi.org/10.1002/spp2.1523","url":null,"abstract":"Abstract Baru is a genus that includes several large mekosuchine crocodylians from the Oligo‐Miocene of Australia. Here we describe Baru iylwenpeny sp. nov. from a large sample of cranial bones from the Upper Miocene Alcoota Local Fauna of the Northern Territory. Baru iylwenpeny can be diagnosed by several autapomorphies that include, but are not limited to: extreme reduction of the pneumatic foramina associated with the diverticula that invade the bones of the suspensorium; and enlargement of the postcaniniform maxillary teeth resulting in crowding of the postcaniniform alveoli and a reduction in the number of maxillary alveoli to 12. The new species is the geologically youngest known member of the genus. While species of Baru are a ubiquitous component of Oligo‐Miocene crocodylian assemblages from northern Australia, they are absent from all known Plio‐Pleistocene sites, suggesting the extinction of the genus by the latest Miocene. We suggest that the marked taxonomic turnover of crocodylian assemblages between the Upper Miocene Alcoota Local Fauna and the Lower Pliocene is the result of a short period of severe aridity during the latest Miocene, causing widespread crocodylian extinctions across Australia, followed by the establishment of taxonomically novel crocodylian faunas in the Pliocene. This event mirrors similar contemporary losses of crocodylian diversity in Africa and South America, although these cases are partly driven by local tectonic events. It is likely that late Cenozoic global cooling also played a role in these extinctions.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135484335","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}

引用次数: 0

The last horned armadillos: phylogeny and decline of Peltephilidae (Xenarthra, Cingulata) 最后的角犰狳:角犰狳科的系统发育与衰落

IF 2.3 2区地球科学

Papers in Palaeontology Pub Date : 2023-07-01 DOI: 10.1002/spp2.1514

D. Barasoain, D. Croft, A. Zurita, V. H. Contreras, R. Tomassini

{"title":"The last horned armadillos: phylogeny and decline of Peltephilidae (Xenarthra, Cingulata)","authors":"D. Barasoain, D. Croft, A. Zurita, V. H. Contreras, R. Tomassini","doi":"10.1002/spp2.1514","DOIUrl":"https://doi.org/10.1002/spp2.1514","url":null,"abstract":"Peltephilidae (Xenarthra, Cingulata) is an ancient lineage of medium–large‐sized ‘armadillos’ from South America, characterized by chisel‐shaped molariforms, a U‐shaped dental arcade, and cephalic osteoderms modified into hornlike structures. Although the biochron of the group extends from the early Eocene to the Late Miocene, the most abundant and complete records come from the Early Miocene of Patagonia. Remains from the Late Miocene are very scarce, and the last records of the group are from the Chasicoan Stage (Tortonian). The only taxon known from this interval is Epipeltephilus kanti from the Arroyo Chasicó Formation (9.23 ± 0.09 Ma; Buenos Aires Province, Argentina), a species previously represented only by a few isolated osteoderms. Here we report new remains assigned to E. kanti from the Late Miocene of Loma de Las Tapias Formation (c. 9.0–7.8 Ma; San Juan Province, Argentina), including a hemimandible and several fixed and mobile osteoderms. These new specimens constitute the youngest record of Peltephilidae. The inclusion of E. kanti within Epipeltephilus and the monophyly of the genera Peltephilus and Epipeltephilus are corroborated for the first time through a cladistic analysis. The decline and eventual disappearance of this ‘armadillo’ group in the Late Miocene is chronologically coincident with the replacement of subtropical/tropical environments by more open and arid ones and with the proliferation of other large armadillos such as Vetelia, Macrochorobates, and Macroeuphractus.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"11 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73140905","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}

引用次数: 0

Healed injuries, ontogeny and scleritome construction in a Late Ordovician machaeridian (Annelida, Aphroditiformia) 晚奥陶世机械虫(环节动物，Aphroditiformia)的愈合损伤、个体发育和硬体构造

IF 2.3 2区地球科学

Papers in Palaeontology Pub Date : 2023-07-01 DOI: 10.1002/spp2.1520

L. Parry, G. Edgecombe, J. Bruthansová, J. Vinther

{"title":"Healed injuries, ontogeny and scleritome construction in a Late Ordovician machaeridian (Annelida, Aphroditiformia)","authors":"L. Parry, G. Edgecombe, J. Bruthansová, J. Vinther","doi":"10.1002/spp2.1520","DOIUrl":"https://doi.org/10.1002/spp2.1520","url":null,"abstract":"Machaeridians are armoured annelids that were morphologically diverse during the Palaeozoic. The scleritome developed from fleshy protrusions at the base of each parapodium, with alternating segments giving rise to differentiated inner and outer shell plates. The elytra‐like anatomy of the shell‐bearing soft tissues and distinctive jaw apparatus support an affinity of machaeridians with aphroditacean scaleworms. While frequently found as disarticulated remains, whole scleritomes of machaeridians are rare. Only a few species are represented by multiple articulated individuals, rendering many aspects of our knowledge of scleritome construction and growth uncertain. Here we describe a collection of articulated scleritomes of the plumulitid machaeridian Plumulites tafennaensis Chauvel from the Upper Ordovician (Katian) Upper Tiouririne Formation of Morocco that includes individuals representing both adult and juvenile stages. These scleritomes shed light on the morphology of the anterior region in plumulitids and show an increase in the number of shell plates with increasing size, suggesting that unlike some derived lepidocoleids, at least some plumulitids added segments repeatedly during ontogeny. Shell plates with a distinctive umbo have previously been assigned exclusively to the anterior region, but our material shows that they are present along the scleritome, with corresponding sclerites on the opposite side of the skeleton showing normal morphologies. We suggest that these plates are abnormal and best explained as healed injuries, replacing plates that had been previously removed from the body, demonstrating the capacity for machaeridians to regenerate lost body parts, a feature that is widespread in living annelids.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"50 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85709403","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}

引用次数: 0

Cryptic moulting behaviour of some Carboniferous Ostracoda 石炭纪某些介形虫的隐换羽行为

IF 2.3 2区地球科学

Papers in Palaeontology Pub Date : 2023-07-01 DOI: 10.1002/spp2.1519

E. Olempska, D. Mundy, M. Zatoń

{"title":"Cryptic moulting behaviour of some Carboniferous Ostracoda","authors":"E. Olempska, D. Mundy, M. Zatoń","doi":"10.1002/spp2.1519","DOIUrl":"https://doi.org/10.1002/spp2.1519","url":null,"abstract":"Monospecific accumulations of ostracods, represented by spine‐bearing Janischewskya? sp. and a smooth‐shelled Cavellina? sp., were detected inside the body chamber, siphuncle and camerae of three cephalopod specimens (a nautiloid and two goniatites) from the Carboniferous (Mississippian) Cracoean reefs of North Yorkshire, UK. The ostracods occur as isolated valves packed together and are well‐preserved, with delicate spines of Janischewskya? sp. still intact on numerous specimens. Such a mode of ostracod preservation inside the cephalopod conchs and their paucity in the surrounding matrix outside the shells indicate that the valves were not concentrated due to sedimentary processes. Rather, the ostracods deliberately entered the empty cephalopod shells in order to seek sheltered habitats for moulting. In the case of the smooth‐shelled Cavellina? sp., the ostracod valves preserved inside a camera of the nautiloid have similar size, indicating that a synchronized mass moulting took place in this species. Additionally, the presence of putative eggs closely associated with the spine‐bearing Janischewskya? sp. valves inside a siphuncle of the nautiloid shows that the empty conchs could have also served as safe places for egg deposition. The present finds are thus the first examples of cryptic moulting behaviour in ostracods. They also imply that such behaviour in this group of arthropods has a long evolutionary history, at least since the Carboniferous, and potentially may persist in present day ostracods.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"135 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79808791","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}

引用次数: 0

The siphonotretide brachiopod Schizambon from the Early Ordovician of South China: ontogeny and affinity 华南早奥陶世齐孔肽类腕足动物:个体发育与亲缘关系

IF 2.3 2区地球科学

Papers in Palaeontology Pub Date : 2023-07-01 DOI: 10.1002/spp2.1517

H. Jahangir, Zhiliang Zhang, L. Popov, L. Holmer, M. Ghobadi Pour, Renbin Zhan

{"title":"The siphonotretide brachiopod Schizambon from the Early Ordovician of South China: ontogeny and affinity","authors":"H. Jahangir, Zhiliang Zhang, L. Popov, L. Holmer, M. Ghobadi Pour, Renbin Zhan","doi":"10.1002/spp2.1517","DOIUrl":"https://doi.org/10.1002/spp2.1517","url":null,"abstract":"Schizambon is one of the earliest and most distinctive genera in the Order Siphonotretida. However, current knowledge of siphonotretide phylogeny and early evolution requires understanding of their earliest ontogeny. In this study, the new species Schizambon tongziensis from the Tungtzu Formation at Honghuayuan section in Guizhou Province, South China is described; it is also the first record of Schizambon in South China. The new well‐preserved specimens shed light on the ontogeny, palaeobiogeographical distribution, phylogeny and early evolution of siphonotretide brachiopods. Characters of metamorphic shells on both valves, outlined by distinct halos, show that Schizambon had a planktotrophic ‘paterinide‐type’ larva, typical of many early Palaeozoic brachiopods. Based on the newly obtained data it is inferred that the free‐swimming larva of Schizambon settled directly on the ventral side of the body, and this type of ontogeny is probably true for other siphonotretides. The divergence of Schizambon from the main siphonotretide lineage probably happened prior to the Guzhangian Age, well before the occurrence of major biodiversification within the order.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"46 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78661321","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}

引用次数: 0