Estelestes ensis Novaceck et al., 1991 is a curious Paleogene metatherian mammal recognized on the basis of a single specimen from Baja California (Mexico) in southern North America. It comes from early Eocene (Wasatchian age) levels of the Las Tetas de Cabra Formation at “Marsupial Hill” in the Lomas Las Tetas de Cabra site (also known as Punta Prieta; see Novaceck et al., 1991). The specimen consists of a fragmentary left mandible with the last premolar, the roots of the first two molars, and almost complete last two molars (Fig. 1). It was referred to the Didelphini (Marsupialia, Didelphimorphia, Didelphidae, Didelphinae) even though Novaceck et al. (1991) stated that the overall morphology of the type specimen poses intriguing problems regarding its relationships. For example, the very deep, robust jaw of Estelestes distinguishes it from any other Holarctic “didelphine” (at the time Novaceck et al., 1991 published their work, both the concept and extent of Didelphidae and Didelphinae were much broader than today). Interestingly, they concluded that Estelestes had close affinities with “Mirandotherium” (lapsus calami for Mirandatherium), from the early Eocene of Itaboraí, in southeastern Brazil. “Resemblance between the two taxa is nevertheless striking, once again raising the possibility of close relationships among certain early members of the Northern Hemisphere and South American Didelphinae” (Novaceck et al., 1991, p. 16). The affinities of Mirandatherium are contested, having been regarded as part of the Didelphimorphia (e.g., de Paula Couto, 1952a) or Microbiotheria (e.g., Marshall, 1987; McKenna and Bell, 1997; Oliveira and Goin, 2011), or even as an alphadontian (Carneiro, 2019).
Estelestes ensis Novaceck et al.， 1991，是一种奇怪的古近纪后生哺乳动物，是在北美南部下加利福尼亚(墨西哥)的一个单一标本的基础上被识别出来的。它来自始新世早期(Wasatchian时代)的Las Tetas de Cabra组，位于Lomas Las Tetas de Cabra遗址(也称为Punta Prieta;参见Novaceck et al.， 1991)。该标本由一个残缺的左下颌骨和最后的前磨牙、前两颗磨牙的根部以及几乎完整的后两颗磨牙组成(图1)。尽管Novaceck等人(1991)指出，该模式标本的整体形态对其关系提出了有趣的问题，但它被称为Didelphini(有袋目，didelphimorphiia, Didelphidae, Didelphinae)。例如，Estelestes非常深、强壮的颚使它与任何其他的全北极“didelphine”(在Novaceck等人1991年发表他们的工作时，Didelphidae和Didelphinae的概念和范围都比今天广泛得多)区分。有趣的是，他们得出结论，Estelestes与巴西东南部Itaboraí始新世早期的“Mirandatherium”(Mirandatherium的lapsus calami)有着密切的关系。“尽管如此，这两个分类群之间的相似之处还是惊人的，这再次提出了北半球和南美洲Didelphinae的某些早期成员之间存在密切关系的可能性”(Novaceck et al.， 1991, p. 16)。Mirandatherium的亲缘关系是有争议的，被认为是didelphimorphiia(例如，de Paula Couto, 1952a)或Microbiotheria(例如，Marshall, 1987;麦肯纳和贝尔，1997;Oliveira and Goin, 2011)，或者甚至是作为一个字母专家(Carneiro, 2019)。
{"title":"†Estelestes ensis (Mammalia, Metatheria) from the early Eocene of Baja California (Mexico) as a generalized polydolopimorphian","authors":"F. Goin, E. C. Vieytes, V. Crespo, É. Oliveira","doi":"10.1017/jpa.2022.105","DOIUrl":"https://doi.org/10.1017/jpa.2022.105","url":null,"abstract":"Estelestes ensis Novaceck et al., 1991 is a curious Paleogene metatherian mammal recognized on the basis of a single specimen from Baja California (Mexico) in southern North America. It comes from early Eocene (Wasatchian age) levels of the Las Tetas de Cabra Formation at “Marsupial Hill” in the Lomas Las Tetas de Cabra site (also known as Punta Prieta; see Novaceck et al., 1991). The specimen consists of a fragmentary left mandible with the last premolar, the roots of the first two molars, and almost complete last two molars (Fig. 1). It was referred to the Didelphini (Marsupialia, Didelphimorphia, Didelphidae, Didelphinae) even though Novaceck et al. (1991) stated that the overall morphology of the type specimen poses intriguing problems regarding its relationships. For example, the very deep, robust jaw of Estelestes distinguishes it from any other Holarctic “didelphine” (at the time Novaceck et al., 1991 published their work, both the concept and extent of Didelphidae and Didelphinae were much broader than today). Interestingly, they concluded that Estelestes had close affinities with “Mirandotherium” (lapsus calami for Mirandatherium), from the early Eocene of Itaboraí, in southeastern Brazil. “Resemblance between the two taxa is nevertheless striking, once again raising the possibility of close relationships among certain early members of the Northern Hemisphere and South American Didelphinae” (Novaceck et al., 1991, p. 16). The affinities of Mirandatherium are contested, having been regarded as part of the Didelphimorphia (e.g., de Paula Couto, 1952a) or Microbiotheria (e.g., Marshall, 1987; McKenna and Bell, 1997; Oliveira and Goin, 2011), or even as an alphadontian (Carneiro, 2019).","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"533 - 538"},"PeriodicalIF":1.4,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45182285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Fürsich, Suraj Bhosale, Matthias Alberti, D. Pandey
Abstract. A diverse molluscan assemblage dominated by turritellid gastropods found in Kachchh, western India, has been interpreted in the past as Late Jurassic (Oxfordian) in age, based on associated undoubtedly Oxfordian ammonites. Recently, several investigations focused on the assemblage dealing with taxonomic, paleoecological, and evolutionary aspects. An analysis of the associated bivalve fauna, foraminiferal assemblage, and the geological context strongly suggests a Miocene rather than a Jurassic age and invalidates several conclusions drawn from the alleged Jurassic age of the fossils.
{"title":"Miocene instead of Jurassic: the importance of sound fieldwork for paleontological data analysis","authors":"F. Fürsich, Suraj Bhosale, Matthias Alberti, D. Pandey","doi":"10.1017/jpa.2022.106","DOIUrl":"https://doi.org/10.1017/jpa.2022.106","url":null,"abstract":"Abstract. A diverse molluscan assemblage dominated by turritellid gastropods found in Kachchh, western India, has been interpreted in the past as Late Jurassic (Oxfordian) in age, based on associated undoubtedly Oxfordian ammonites. Recently, several investigations focused on the assemblage dealing with taxonomic, paleoecological, and evolutionary aspects. An analysis of the associated bivalve fauna, foraminiferal assemblage, and the geological context strongly suggests a Miocene rather than a Jurassic age and invalidates several conclusions drawn from the alleged Jurassic age of the fossils.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"341 - 346"},"PeriodicalIF":1.4,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41443168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The morphology of Zygospira, an early atrypide brachiopod, was analyzed using a multivariate approach. Principal component analysis and discriminant analysis clearly differentiated species as they are currently defined primarily based on differences in shell size and ornamentation but not in terms of overall shell shape. The older Zygospira modesta was able to persist into the late Katian (Richmondian) while smaller early species in other brachiopod lineages mostly went extinct. This may have been possible through niche partitioning because the smaller shells have been found attached to other filter feeders and no larger species have been found in these associations so far. This could represent a rare example of sympatric speciation preserved in the fossil record. In the future, detailed study of the spiralia and their associated structures may provide clues as to the ultimate evolutionary affinities of this group in relation to the other atrypide brachiopods evolving at this time.
{"title":"Sympatric speciation driving evolution of Late Ordovician brachiopod Zygospira in eastern North America","authors":"Colin D. Sproat, Jessica S.A. McLeod","doi":"10.1017/jpa.2022.102","DOIUrl":"https://doi.org/10.1017/jpa.2022.102","url":null,"abstract":"Abstract. The morphology of Zygospira, an early atrypide brachiopod, was analyzed using a multivariate approach. Principal component analysis and discriminant analysis clearly differentiated species as they are currently defined primarily based on differences in shell size and ornamentation but not in terms of overall shell shape. The older Zygospira modesta was able to persist into the late Katian (Richmondian) while smaller early species in other brachiopod lineages mostly went extinct. This may have been possible through niche partitioning because the smaller shells have been found attached to other filter feeders and no larger species have been found in these associations so far. This could represent a rare example of sympatric speciation preserved in the fossil record. In the future, detailed study of the spiralia and their associated structures may provide clues as to the ultimate evolutionary affinities of this group in relation to the other atrypide brachiopods evolving at this time.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"292 - 317"},"PeriodicalIF":1.4,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45011970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"JPA volume 97 issue 1 Cover and Front matter","authors":"","doi":"10.1017/jpa.2023.9","DOIUrl":"https://doi.org/10.1017/jpa.2023.9","url":null,"abstract":"","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":" ","pages":"f1 - f2"},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44196540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chengxi Wu, K. Pang, Zhe Chen, Xiaopeng Wang, Chuanming Zhou, B. Wan, Xunlai Yuan, S. Xiao
The terminal Ediacaran Shibantan biota (~550–543 Ma) from the Dengying Formation in the Yangtze Gorges area of South China represents one of the rare examples of carbonate-hosted Ediacara-type macrofossil assemblages. In addition to the numerically dominant taxa—the non-biomineralizing tubular fossil Wutubus and discoidal fossils Aspidella and Hiemalora, the Shibantan biota also bears a moderate diversity of frondose fossils, including Pteridinium, Rangea, Arborea, and Charnia. In this paper, we report two species of the rangeomorph genus Charnia, including the type species Charnia masoni Ford, 1958 emend. and Charnia gracilis new species, from the Shibantan biota. Most of the Shibantan Charnia specimens preserve only the petalodium, with a few bearing the holdfast and stem. Despite overall architectural similarities to other Charnia species, the Shibantan specimens of Charnia gracilis n. sp. are distinct in their relatively straight, slender, and more acutely angled first-order branches. They also show evidence that may support a two-stage growth model and a epibenthic sessile lifestyle. Charnia fossils described herein represent one of the youngest occurrences of this genus and extend its paleogeographic and stratigraphic distributions. Our discovery also highlights the notable diversity of the Shibantan biota, which contains examples of a wide range of Ediacaran morphogroups. UUID: http://zoobank.org/837216cd-4a4a-4e13-89e2-ee354ba48a4c
{"title":"The rangeomorph fossil Charnia from the Ediacaran Shibantan biota in the Yangtze Gorges area, South China","authors":"Chengxi Wu, K. Pang, Zhe Chen, Xiaopeng Wang, Chuanming Zhou, B. Wan, Xunlai Yuan, S. Xiao","doi":"10.1017/jpa.2022.97","DOIUrl":"https://doi.org/10.1017/jpa.2022.97","url":null,"abstract":"\u0000 The terminal Ediacaran Shibantan biota (~550–543 Ma) from the Dengying Formation in the Yangtze Gorges area of South China represents one of the rare examples of carbonate-hosted Ediacara-type macrofossil assemblages. In addition to the numerically dominant taxa—the non-biomineralizing tubular fossil Wutubus and discoidal fossils Aspidella and Hiemalora, the Shibantan biota also bears a moderate diversity of frondose fossils, including Pteridinium, Rangea, Arborea, and Charnia. In this paper, we report two species of the rangeomorph genus Charnia, including the type species Charnia masoni Ford, 1958 emend. and Charnia gracilis new species, from the Shibantan biota. Most of the Shibantan Charnia specimens preserve only the petalodium, with a few bearing the holdfast and stem. Despite overall architectural similarities to other Charnia species, the Shibantan specimens of Charnia gracilis n. sp. are distinct in their relatively straight, slender, and more acutely angled first-order branches. They also show evidence that may support a two-stage growth model and a epibenthic sessile lifestyle. Charnia fossils described herein represent one of the youngest occurrences of this genus and extend its paleogeographic and stratigraphic distributions. Our discovery also highlights the notable diversity of the Shibantan biota, which contains examples of a wide range of Ediacaran morphogroups.\u0000 UUID: http://zoobank.org/837216cd-4a4a-4e13-89e2-ee354ba48a4c","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48068470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The trilobite Needmorella new genus, with type species N. simoni new genus new species from the late Emsian to mid-Eifelian Needmore Shale of West Virginia, is a distinctive member of the subfamily Synphoriinae. It also occurs in the same formation in Pennsylvania and Virginia. It is not very similar to other Devonian representatives of the subfamily and is considered to have its origins in a morphologically less-derived ancestor because it shares certain similarities with Silurian genera, including the very short anterior cephalic border unmodified by crenulations or spines, S2 that is not largely reduced to a deep pit adaxially, the relatively low inflation of L3, and the well-defined interpleural furrows on the pygidium. Other particularly distinctive characters of the genus include the very long genal spines and the abaxially inflated and expanded posterior pleural bands on the thorax and pygidium that project slightly distally. The conventional concept of the Devonian synphoriine Anchiopsis Delo, 1935 appears to be incompatible with the holotype of the type species, judging from the early illustrations of the specimen, and the genus could be a synonym of Synphoria Clarke, 1894.
{"title":"Needmorella, a new trilobite genus of the Synphoriinae (Dalmanitidae) from the Lower–Middle Devonian of West Virginia","authors":"D. Holloway, Brian M. Scott","doi":"10.1017/jpa.2022.96","DOIUrl":"https://doi.org/10.1017/jpa.2022.96","url":null,"abstract":"Abstract. The trilobite Needmorella new genus, with type species N. simoni new genus new species from the late Emsian to mid-Eifelian Needmore Shale of West Virginia, is a distinctive member of the subfamily Synphoriinae. It also occurs in the same formation in Pennsylvania and Virginia. It is not very similar to other Devonian representatives of the subfamily and is considered to have its origins in a morphologically less-derived ancestor because it shares certain similarities with Silurian genera, including the very short anterior cephalic border unmodified by crenulations or spines, S2 that is not largely reduced to a deep pit adaxially, the relatively low inflation of L3, and the well-defined interpleural furrows on the pygidium. Other particularly distinctive characters of the genus include the very long genal spines and the abaxially inflated and expanded posterior pleural bands on the thorax and pygidium that project slightly distally. The conventional concept of the Devonian synphoriine Anchiopsis Delo, 1935 appears to be incompatible with the holotype of the type species, judging from the early illustrations of the specimen, and the genus could be a synonym of Synphoria Clarke, 1894.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"355 - 365"},"PeriodicalIF":1.4,"publicationDate":"2022-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43408553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Seven species of cornulitids, one unidentified tubicolous shell, and the problematic bryozoan Lagenosypho Spandel, 1898 are here described from the Katian of Baltica. Three new species—Cornulites lindae new species, Cornulites meidlai new species, and Conchicolites kroegeri new species—are described. The unidentified tubicolous organism has punctate shell structure and setae-like structures that can best be affiliated with lophophorates. The Hirmuse fauna indicates that the diversity and number of cornulitids in the Ordovician of Baltica has been underestimated and it is likely that the Baltic cornulitid fauna was as diverse and abundant as the fauna of Laurentia. Clay mud-bottom environments supported the highest cornulitid diversity in the Late Ordovician of Baltica. The occurrence of intermediate forms indicates that some tentaculitid characters, e.g., regular annulation and a nearly straight shell, which were thought to be apomorphies of free-living tentaculitids, were actually inherited from ancestral cornulitids. The cornulitid fauna of the Late Ordovician of Laurentia somewhat resembles the cornulitid fauna of the Late Ordovician of Baltica, but there are fewer common faunal elements between Gondwana and Baltica.
{"title":"Cornulitid tubeworms and other calcareous tubicolous organisms from the Hirmuse Formation (Katian, Upper Ordovician) of northern Estonia","authors":"O. Vinn, A. Madison, Mark A. Wilson, U. Toom","doi":"10.1017/jpa.2022.89","DOIUrl":"https://doi.org/10.1017/jpa.2022.89","url":null,"abstract":"Abstract. Seven species of cornulitids, one unidentified tubicolous shell, and the problematic bryozoan Lagenosypho Spandel, 1898 are here described from the Katian of Baltica. Three new species—Cornulites lindae new species, Cornulites meidlai new species, and Conchicolites kroegeri new species—are described. The unidentified tubicolous organism has punctate shell structure and setae-like structures that can best be affiliated with lophophorates. The Hirmuse fauna indicates that the diversity and number of cornulitids in the Ordovician of Baltica has been underestimated and it is likely that the Baltic cornulitid fauna was as diverse and abundant as the fauna of Laurentia. Clay mud-bottom environments supported the highest cornulitid diversity in the Late Ordovician of Baltica. The occurrence of intermediate forms indicates that some tentaculitid characters, e.g., regular annulation and a nearly straight shell, which were thought to be apomorphies of free-living tentaculitids, were actually inherited from ancestral cornulitids. The cornulitid fauna of the Late Ordovician of Laurentia somewhat resembles the cornulitid fauna of the Late Ordovician of Baltica, but there are fewer common faunal elements between Gondwana and Baltica.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"38 - 46"},"PeriodicalIF":1.4,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47379184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. We report new, fossiliferous Paleogene Naran Bulak Formation localities from the central-eastern part of the Nemegt Basin of the Gobi Desert, Mongolia. Early Paleogene localities have been identified previously only in the western half of the Nemegt Basin. The new localities, near the town of Daus, are also noteworthy for their geographical proximity to Ukhaa Tolgod, a Late Cretaceous Djadokhta Formation locality known for its numerous dinosaur, mammal, and lizard fossils. The Daus section consists of the Zhigden, Naran, and Bumban members of the Naran Bulak Formation at three localities, and mammal and ostracode fossils were discovered in the Naran Member. Noteworthy discoveries are a dentary of the pantodont Archaeolambda cf. A. planicanina, postcrania of Pantolambdodon, a skull of the gliroid Gomphos, and a partial skull with a worn and damaged dentition provisionally identified as an arctostylopid. Biostratigraphy has been the primary means of dating Paleogene Asian faunas, however, the local fauna from the new localities does not fit easily with established patterns. The Naran Member and Archaeolambda planicanina and the arctostylopid Palaeostylops typically have been allied with the Gashatan Asian Land Mammal Age (ALMA) and attributed to the latest Paleocene. By contrast, Gomphos repeatedly has been found in the Bumban Member and assigned a Bumbanian ALMA, which has been considered as the earliest Eocene. Pantolambdodon has been reported from middle Eocene Arshatan and Irdinmanhan ALMA beds. The co-occurrence of these taxa in Naran Member beds complicates the temporal interpretation of the new localities and the reliability of broader biostratigraphic patterns.
{"title":"A new Early Paleogene fossil mammal locality in the central-eastern Nemegt Basin, Gobi Desert, Mongolia, and notes on mammalian biostratigraphy","authors":"K. Yo, Eva A. Hoffman, M. O'Leary, M. Novacek","doi":"10.1017/jpa.2022.85","DOIUrl":"https://doi.org/10.1017/jpa.2022.85","url":null,"abstract":"Abstract. We report new, fossiliferous Paleogene Naran Bulak Formation localities from the central-eastern part of the Nemegt Basin of the Gobi Desert, Mongolia. Early Paleogene localities have been identified previously only in the western half of the Nemegt Basin. The new localities, near the town of Daus, are also noteworthy for their geographical proximity to Ukhaa Tolgod, a Late Cretaceous Djadokhta Formation locality known for its numerous dinosaur, mammal, and lizard fossils. The Daus section consists of the Zhigden, Naran, and Bumban members of the Naran Bulak Formation at three localities, and mammal and ostracode fossils were discovered in the Naran Member. Noteworthy discoveries are a dentary of the pantodont Archaeolambda cf. A. planicanina, postcrania of Pantolambdodon, a skull of the gliroid Gomphos, and a partial skull with a worn and damaged dentition provisionally identified as an arctostylopid. Biostratigraphy has been the primary means of dating Paleogene Asian faunas, however, the local fauna from the new localities does not fit easily with established patterns. The Naran Member and Archaeolambda planicanina and the arctostylopid Palaeostylops typically have been allied with the Gashatan Asian Land Mammal Age (ALMA) and attributed to the latest Paleocene. By contrast, Gomphos repeatedly has been found in the Bumban Member and assigned a Bumbanian ALMA, which has been considered as the earliest Eocene. Pantolambdodon has been reported from middle Eocene Arshatan and Irdinmanhan ALMA beds. The co-occurrence of these taxa in Naran Member beds complicates the temporal interpretation of the new localities and the reliability of broader biostratigraphic patterns.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"243 - 266"},"PeriodicalIF":1.4,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43143447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The type specimens of Eothinoceras americanum Ulrich et al., 1944, type species of the genus Eothinoceras Ulrich et al., 1944, are revised based on new photographic material. The resulting interpretation of the conch shape of Eothinoceras shows that the type species is an endogastric cyrtocone, necessitating the restriction of Eothinoceras to the type species and requiring the revision of the family Eothinoceratidae and the order Cyrtocerinida. A new scheme for classifying the genera of the order Cyrtocerinida into its three families is proposed: (1) Eothinoceratidae Ulrich et al., 1944, containing the genera Eothinoceras; Protothinoceras Chen and Teichert, 1987; Mesothinoceras Chen and Teichert, 1987; and Conothinoceras Chen and Teichert, 1987; (2) Cyrtocerinidae Flower, 1946, including Cyrtocerina Billings, 1865; Tangshanoceras Chen, 1976; and Centrocyrtocerina Stait, 1983; (3) Bathmoceratidae Gill, 1871, containing Bathmoceras Barrande, 1865; Saloceras Evans, 2005; Sacerdosoceras Evans, 2005; Margaritoceras Cecioni and Flower, 1985; and Mutveiceras Cichowolski et al., 2014.
{"title":"Revision of Eothinoceras and the status of the Eothinoceratidae (Cyrtocerinida, Multiceratoidea, Cephalopoda)","authors":"D. H. Evans, Marcela Cichowolski","doi":"10.1017/jpa.2022.99","DOIUrl":"https://doi.org/10.1017/jpa.2022.99","url":null,"abstract":"Abstract. The type specimens of Eothinoceras americanum Ulrich et al., 1944, type species of the genus Eothinoceras Ulrich et al., 1944, are revised based on new photographic material. The resulting interpretation of the conch shape of Eothinoceras shows that the type species is an endogastric cyrtocone, necessitating the restriction of Eothinoceras to the type species and requiring the revision of the family Eothinoceratidae and the order Cyrtocerinida. A new scheme for classifying the genera of the order Cyrtocerinida into its three families is proposed: (1) Eothinoceratidae Ulrich et al., 1944, containing the genera Eothinoceras; Protothinoceras Chen and Teichert, 1987; Mesothinoceras Chen and Teichert, 1987; and Conothinoceras Chen and Teichert, 1987; (2) Cyrtocerinidae Flower, 1946, including Cyrtocerina Billings, 1865; Tangshanoceras Chen, 1976; and Centrocyrtocerina Stait, 1983; (3) Bathmoceratidae Gill, 1871, containing Bathmoceras Barrande, 1865; Saloceras Evans, 2005; Sacerdosoceras Evans, 2005; Margaritoceras Cecioni and Flower, 1985; and Mutveiceras Cichowolski et al., 2014.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"347 - 354"},"PeriodicalIF":1.4,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46309350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Ray-finned fishes comprise nearly half of extant vertebrate species and include several ancient lineages with fossil records that stretch over 200 Myr in time. One of these old clades, the sturgeons and paddlefishes, is distributed across the Northern Hemisphere and includes some of the largest known freshwater fishes. Yet, the fossil record of this lineage (Acipenseriformes) is poor compared to similarly ancient ray-finned fish clades. Here, I describe sturgeon fossils from two geological units in North America < 10 Myr younger than the Cretaceous-Paleogene boundary. Both come from individuals of ∼1.5 m in length. These Paleogene forms establish the long history of large body size in Acipenseriforms and reveal sturgeons were some of the largest inhabitants of freshwater ecosystems that were still recovering from the Cretaceous-Paleogene extinction.
{"title":"Evidence of large sturgeons in the Paleocene of North America","authors":"C. Brownstein","doi":"10.1017/jpa.2022.87","DOIUrl":"https://doi.org/10.1017/jpa.2022.87","url":null,"abstract":"Abstract. Ray-finned fishes comprise nearly half of extant vertebrate species and include several ancient lineages with fossil records that stretch over 200 Myr in time. One of these old clades, the sturgeons and paddlefishes, is distributed across the Northern Hemisphere and includes some of the largest known freshwater fishes. Yet, the fossil record of this lineage (Acipenseriformes) is poor compared to similarly ancient ray-finned fish clades. Here, I describe sturgeon fossils from two geological units in North America < 10 Myr younger than the Cretaceous-Paleogene boundary. Both come from individuals of ∼1.5 m in length. These Paleogene forms establish the long history of large body size in Acipenseriforms and reveal sturgeons were some of the largest inhabitants of freshwater ecosystems that were still recovering from the Cretaceous-Paleogene extinction.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"218 - 222"},"PeriodicalIF":1.4,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48044766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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