The suborder Phacopina, characterized by schizochroal eyes, is among the most common groups of trilobites in Devonian strata. The marine sediments of the Famennian in western Junggar, Xinjiang, contain abundant low-disparity phacopids, which have previously been designated to Omegops accipitrinus mobilis, Phacops circumspectans tuberculosus, and Omegops cornelius on the basis of small numbers of poorly preserved specimens. In this study, these phacopids were identified as two new species of Omegops, O. honggulelengensis n. sp. and O. xiangi n. sp., on the basis of nearly 200 well-preserved specimens. The intraspecific variations of eye lenses of these specimens were quantitatively analyzed. On the basis of differences in the total number, number of dorsoventral files, and arrangement of the eye lenses, the absence of lenses in the middle part of the visual surface, and asymmetry of the number and/or arrangement of lenses in the two eyes, it was concluded that the reasons for intraspecific variation in eye lenses of Late Devonian Omegops from western Junggar were different from previously described factors but were likely genetic or embryological malfunctions or abnormalities caused by pathological conditions. Diversity of lenses in the schizochroal eyes shows that the number and arrangement of eye lenses was not stable in Phacopina. Therefore, many specimens are needed for quantitative study to determine the true characteristics of the number or arrangement of eye lenses when these features are used in the systematic taxonomy of Phacopina. UUID: http://zoobank.org/6bd14390-05fe-45ad-8eeb-3bf397a46a68
以裂眼为特征的三叶虫亚目是泥盆纪地层中最常见的三叶虫类群之一。新疆准噶尔西部法门期海相沉积物中含有丰富的低视差棘足虫，根据少量保存较差的标本，已将其确定为运动棘足虫、环棘足虫和角棘足虫。本研究根据近200份保存完好的标本，鉴定出这两种棘足类为2个新种:O. honggulelengensis n. sp.和O. xiangi n. sp.。定量分析了这些标本眼晶状体的种内变异。根据两眼晶状体总数、背腹侧晶状体数量和排列方式的差异，视表面中部没有晶状体，以及两眼晶状体数量和(或)排列方式的不对称，结论是，准噶尔西部晚泥盆世欧米伽虫晶状体种内变异的原因与先前描述的因素不同，而可能是遗传或胚胎功能障碍或病理条件引起的异常。分裂性眼晶状体的多样性表明菲科皮纳眼晶状体的数量和排列不稳定。因此，在系统分类中使用眼晶状体的数量或排列特征时，需要大量标本进行定量研究，以确定这些特征的真实特征。UUID: http://zoobank.org/6bd14390-05fe-45ad-8eeb-3bf397a46a68
{"title":"Variation in eye lenses of two new Late Devonian phacopid trilobites from western Junggar, NW China","authors":"Ruiwen Zong","doi":"10.1017/jpa.2023.31","DOIUrl":"https://doi.org/10.1017/jpa.2023.31","url":null,"abstract":"\u0000 The suborder Phacopina, characterized by schizochroal eyes, is among the most common groups of trilobites in Devonian strata. The marine sediments of the Famennian in western Junggar, Xinjiang, contain abundant low-disparity phacopids, which have previously been designated to Omegops accipitrinus mobilis, Phacops circumspectans tuberculosus, and Omegops cornelius on the basis of small numbers of poorly preserved specimens. In this study, these phacopids were identified as two new species of Omegops, O. honggulelengensis n. sp. and O. xiangi n. sp., on the basis of nearly 200 well-preserved specimens. The intraspecific variations of eye lenses of these specimens were quantitatively analyzed. On the basis of differences in the total number, number of dorsoventral files, and arrangement of the eye lenses, the absence of lenses in the middle part of the visual surface, and asymmetry of the number and/or arrangement of lenses in the two eyes, it was concluded that the reasons for intraspecific variation in eye lenses of Late Devonian Omegops from western Junggar were different from previously described factors but were likely genetic or embryological malfunctions or abnormalities caused by pathological conditions. Diversity of lenses in the schizochroal eyes shows that the number and arrangement of eye lenses was not stable in Phacopina. Therefore, many specimens are needed for quantitative study to determine the true characteristics of the number or arrangement of eye lenses when these features are used in the systematic taxonomy of Phacopina.\u0000 UUID: http://zoobank.org/6bd14390-05fe-45ad-8eeb-3bf397a46a68","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48427339","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. Pleurocystitid echinoderms are known to have consistent plating in the theca or body. However, many specimens with aberrant plating are known among glyptocystitoids (Glyptocystella, Hadrocystis, Tyrridiocystis, and so on) as well as the new Ordovician species Pleurocystites? scylla, described here from the Benbolt Formation near Thorn Hill, Tennessee, USA. The presence of an extra plate in the holotype of P? scylla is most likely teratological. While teratology is often misconstrued as parasitism and pathology, it is easily recognized among glyptocystitoid rhombiferans because of the conservative nature of plate arrangements found in these taxa. Teratologic features in stemmed echinoderm thecae appear only to alter suture positioning and not significantly change the thecal shape or diminish the diagnosability of a specimen taxonomically.
{"title":"Pleurocystites? scylla, a new species of pleurocystitid rhombiferan, and comments on early echinoderm teratologies","authors":"Aidan Sweeney, C. Sumrall","doi":"10.1017/jpa.2023.17","DOIUrl":"https://doi.org/10.1017/jpa.2023.17","url":null,"abstract":"Abstract. Pleurocystitid echinoderms are known to have consistent plating in the theca or body. However, many specimens with aberrant plating are known among glyptocystitoids (Glyptocystella, Hadrocystis, Tyrridiocystis, and so on) as well as the new Ordovician species Pleurocystites? scylla, described here from the Benbolt Formation near Thorn Hill, Tennessee, USA. The presence of an extra plate in the holotype of P? scylla is most likely teratological. While teratology is often misconstrued as parasitism and pathology, it is easily recognized among glyptocystitoid rhombiferans because of the conservative nature of plate arrangements found in these taxa. Teratologic features in stemmed echinoderm thecae appear only to alter suture positioning and not significantly change the thecal shape or diminish the diagnosability of a specimen taxonomically.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"631 - 638"},"PeriodicalIF":1.4,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41858176","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. New specimens of Cyclocystoides scammaphoris Smith and Paul, 1982, are here reported from the Upper Ordovician Platteville Formation of northern Illinois, Plattin and Decorah groups of east-central Missouri, and Lebanon Limestone of central Tennessee. These fossils reveal skeletal details that provide insight into the anatomy of cyclocystoids. Of particular significance is a network of channels that likely originate near the center of the central disk and extend along the oral side of the radial plates, bifurcating distally two or three times before entering the radial facets on the proximal surface of each marginal ossicle. From here, the network enters a series of facet canals that extend upward through each marginal ossicle, exiting in a linear row of pores. The canals are very similar in size and distribution to the nerve canals in living echinoderms. The axes of the canals, which number up to 500 in some specimens, and those of the radial ducts project proximally away from the oral surface at an elevation angle of about 25°, apparently forming a network that could have converged within the upper part of the body cavity. This origin and function are made clear by the connection between the channel on each radial plate and the radial facet canal pores within each marginal ossicle.
{"title":"New specimens of Cyclocystoides scammaphoris (Echinodermata) from the Upper Ordovician rocks of the American midcontinent with implications for cyclocystoid functional morphology","authors":"D. Kolata, Terry Frank, Asaf Kaplan, T. Guensburg","doi":"10.1017/jpa.2023.33","DOIUrl":"https://doi.org/10.1017/jpa.2023.33","url":null,"abstract":"Abstract. New specimens of Cyclocystoides scammaphoris Smith and Paul, 1982, are here reported from the Upper Ordovician Platteville Formation of northern Illinois, Plattin and Decorah groups of east-central Missouri, and Lebanon Limestone of central Tennessee. These fossils reveal skeletal details that provide insight into the anatomy of cyclocystoids. Of particular significance is a network of channels that likely originate near the center of the central disk and extend along the oral side of the radial plates, bifurcating distally two or three times before entering the radial facets on the proximal surface of each marginal ossicle. From here, the network enters a series of facet canals that extend upward through each marginal ossicle, exiting in a linear row of pores. The canals are very similar in size and distribution to the nerve canals in living echinoderms. The axes of the canals, which number up to 500 in some specimens, and those of the radial ducts project proximally away from the oral surface at an elevation angle of about 25°, apparently forming a network that could have converged within the upper part of the body cavity. This origin and function are made clear by the connection between the channel on each radial plate and the radial facet canal pores within each marginal ossicle.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"639 - 651"},"PeriodicalIF":1.4,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44859987","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. Two species of Teiichispira Yochelson and Jones reported from the Early/Middle Ordovician marine deposits of the San Juan Formation in the Argentine Precordillera are described. The new species Teiichispira teresae n. sp. is a component of the Early/Middle Ordovician marine gastropod assemblage in the studied region; Teiichispira argentina (Kayser), previously known from the San Juan Formation, is described with a complete teleoconch and associated operculum. The opercula of both Teiichispira species are complete and preserved in life position associated with the shell of T. argentina. The unguiculate morphology of the operculum is here interpreted as a mechanism for increasing the shell weight and ensuring anchoring to the substrate in a more or less fixed mode of life for Teiichispira, and as protection. The new occurrence of Teiichispira provides new taxonomic data on early Paleozoic marine gastropods in Argentina and testifies to a wide paleobiogeographical distribution for the genus, restricted to tropical and subtropical regions during the Early/Middle Ordovician.
摘要介绍了阿根廷Precordillera地区早、中奥陶世San Juan组海相沉积中发现的Teiichispira Yochelson和Jones两种。Teiichispira teresae n. sp.是研究区早/中奥陶世海相腹足类组合的组成部分;阿根廷Teiichispira (Kayser)，以前已知来自圣胡安组，描述了一个完整的远程螺壳和相关的盖层。这两种Teiichispira的盖都是完整的，并保存在与阿根廷T.壳相关的生活位置。蝶盖的有蹄类形态在这里被解释为一种增加壳重的机制，并确保在一个或多或少固定的生活模式中锚定在基质上，并作为保护。Teiichispira的新发现为阿根廷早古生代海洋腹足类提供了新的分类资料，证明了该属在早/中奥陶世的热带和亚热带地区具有广泛的古地理分布。
{"title":"Shell and associated operculum in Teiichispira (Macluritidae: Gastropoda) from the Early/Middle Ordovician of the Argentine Precordillera","authors":"V. Bertero, Mariel Ferrari, Marcelo G. Carrera","doi":"10.1017/jpa.2023.7","DOIUrl":"https://doi.org/10.1017/jpa.2023.7","url":null,"abstract":"Abstract. Two species of Teiichispira Yochelson and Jones reported from the Early/Middle Ordovician marine deposits of the San Juan Formation in the Argentine Precordillera are described. The new species Teiichispira teresae n. sp. is a component of the Early/Middle Ordovician marine gastropod assemblage in the studied region; Teiichispira argentina (Kayser), previously known from the San Juan Formation, is described with a complete teleoconch and associated operculum. The opercula of both Teiichispira species are complete and preserved in life position associated with the shell of T. argentina. The unguiculate morphology of the operculum is here interpreted as a mechanism for increasing the shell weight and ensuring anchoring to the substrate in a more or less fixed mode of life for Teiichispira, and as protection. The new occurrence of Teiichispira provides new taxonomic data on early Paleozoic marine gastropods in Argentina and testifies to a wide paleobiogeographical distribution for the genus, restricted to tropical and subtropical regions during the Early/Middle Ordovician.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"549 - 557"},"PeriodicalIF":1.4,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46483275","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}
Hang-Qiang Wang, S. Braddy, J. Botting, Yuandong Zhang
Abstract. An early form of eurypterids (Chelicerata), Archopterus anjiensis n. gen. n. sp., is described from the uppermost Ordovician Wenchang Formation of Anji County, Zhejiang Province, South China. It is the earliest record of eurypterids in China and likely the oldest representative of the Adelophthalmidae. The species, represented by a single specimen, is diagnosed by a ventrally preserved prosoma with a parabolic carapace, Hughmilleria-type prosomal appendages, a short vase-shaped metastoma, and a three-segmented type A (female) genital appendage. The specimen is preserved, together with diverse sponges, graptolites and occasional nautiloids, in a 10 m thick shale of marine deep-water setting. This finding extends the stratigraphic range of adelophthalmids from the previously recorded early Silurian into the Late Ordovician (some 10 million years older) and supports an earlier cryptic phase of eurypterid evolution in Gondwana.
{"title":"The first documentation of an Ordovician eurypterid (Chelicerata) from China","authors":"Hang-Qiang Wang, S. Braddy, J. Botting, Yuandong Zhang","doi":"10.1017/jpa.2023.21","DOIUrl":"https://doi.org/10.1017/jpa.2023.21","url":null,"abstract":"Abstract. An early form of eurypterids (Chelicerata), Archopterus anjiensis n. gen. n. sp., is described from the uppermost Ordovician Wenchang Formation of Anji County, Zhejiang Province, South China. It is the earliest record of eurypterids in China and likely the oldest representative of the Adelophthalmidae. The species, represented by a single specimen, is diagnosed by a ventrally preserved prosoma with a parabolic carapace, Hughmilleria-type prosomal appendages, a short vase-shaped metastoma, and a three-segmented type A (female) genital appendage. The specimen is preserved, together with diverse sponges, graptolites and occasional nautiloids, in a 10 m thick shale of marine deep-water setting. This finding extends the stratigraphic range of adelophthalmids from the previously recorded early Silurian into the Late Ordovician (some 10 million years older) and supports an earlier cryptic phase of eurypterid evolution in Gondwana.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"606 - 611"},"PeriodicalIF":1.4,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42718946","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}
Z. Sun, Aihua Yang, Fangchen Zhao, A. Zhuravlev, Bing Pan, Chunlin Hu, Qian Feng, Xi Chen, Maoyan Zhu
Abstract. The western Mongolian Lake Zone was a Neoproterozoic to early Paleozoic volcanic arc where tuffs, lavas, fossiliferous siliciclastics, and carbonates accumulated during the early Cambrian. An uppermost Cambrian Series 2 (upper Stage 4) trilobite assemblage is described here from the Burgasutay Formation representing a continuous lower Cambrian succession at the Seer Ridge of the Great Lake Depression. The new assemblage is dominated by dorypygids and consists of 13 trilobite genera belonging to nine families including Catinouyia heyunensis new species. These fossils comprise the youngest and richest lower Cambrian trilobite assemblage in Mongolia. The composition of the Lake Zone fauna suggests its biogeographic affinity with the Siberian Platform and Altay-Sayan Foldbelt, but the presence of inouyiids also implies a connection of this region with East Gondwana.
{"title":"New trilobite assemblage from the lower Cambrian (upper Stage 4) of the Lake Zone, western Mongolia","authors":"Z. Sun, Aihua Yang, Fangchen Zhao, A. Zhuravlev, Bing Pan, Chunlin Hu, Qian Feng, Xi Chen, Maoyan Zhu","doi":"10.1017/jpa.2023.23","DOIUrl":"https://doi.org/10.1017/jpa.2023.23","url":null,"abstract":"Abstract. The western Mongolian Lake Zone was a Neoproterozoic to early Paleozoic volcanic arc where tuffs, lavas, fossiliferous siliciclastics, and carbonates accumulated during the early Cambrian. An uppermost Cambrian Series 2 (upper Stage 4) trilobite assemblage is described here from the Burgasutay Formation representing a continuous lower Cambrian succession at the Seer Ridge of the Great Lake Depression. The new assemblage is dominated by dorypygids and consists of 13 trilobite genera belonging to nine families including Catinouyia heyunensis new species. These fossils comprise the youngest and richest lower Cambrian trilobite assemblage in Mongolia. The composition of the Lake Zone fauna suggests its biogeographic affinity with the Siberian Platform and Altay-Sayan Foldbelt, but the presence of inouyiids also implies a connection of this region with East Gondwana.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"577 - 590"},"PeriodicalIF":1.4,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44326320","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. Chiniquodontidae is a family of nonmammaliaform probainognathian cynodonts with occurrences in the Middle to Late Triassic of Africa and South America (Brazil and Argentina). The history of the family is marked by changes in composition and revisions due to the poor preservation of the first discovered specimens. Currently, Chiniquodontidae includes two genera and six species. Here, we apply the computed tomography (CT-scan) method to describe and revise the morphology of one of the best-preserved chiniquodontid specimens (MCP 1600 PV, holotype of ‘Probelesodon’ kitchingi Sá-Teixeira, 1982) from Brazil, which allowed the visualization of sutures and the segmentation of each bone. The CT-scan data also revealed some previously undescribed traits due to the presence of matrix covering structures of the skull. In addition, the morphological comparisons revealed differences of MCP 1600 PV in relation to the other chiniquodontids, and eight discrete cranial features not related to ontogeny indicate that ‘Probelesodon’ kitchingi might not be included within Chiniquodon theotonicus Huene, 1936. Therefore, we consider the species valid but propose the new combination Chiniquodon kitchingi. Moreover, the results obtained highlighted the necessity of a reassessment of the family, as well as the description of new specimens, morphometric analyses, and use of CT-scan, when feasible.
{"title":"Anatomy of the holotype of ‘Probelesodon’ kitchingi revisited, a chiniquodontid cynodont (Synapsida, Probainognathia) from the early Late Triassic of southern Brazil","authors":"C. Hoffmann, Marco B. de Andrade, A. Martinelli","doi":"10.1017/jpa.2023.25","DOIUrl":"https://doi.org/10.1017/jpa.2023.25","url":null,"abstract":"Abstract. Chiniquodontidae is a family of nonmammaliaform probainognathian cynodonts with occurrences in the Middle to Late Triassic of Africa and South America (Brazil and Argentina). The history of the family is marked by changes in composition and revisions due to the poor preservation of the first discovered specimens. Currently, Chiniquodontidae includes two genera and six species. Here, we apply the computed tomography (CT-scan) method to describe and revise the morphology of one of the best-preserved chiniquodontid specimens (MCP 1600 PV, holotype of ‘Probelesodon’ kitchingi Sá-Teixeira, 1982) from Brazil, which allowed the visualization of sutures and the segmentation of each bone. The CT-scan data also revealed some previously undescribed traits due to the presence of matrix covering structures of the skull. In addition, the morphological comparisons revealed differences of MCP 1600 PV in relation to the other chiniquodontids, and eight discrete cranial features not related to ontogeny indicate that ‘Probelesodon’ kitchingi might not be included within Chiniquodon theotonicus Huene, 1936. Therefore, we consider the species valid but propose the new combination Chiniquodon kitchingi. Moreover, the results obtained highlighted the necessity of a reassessment of the family, as well as the description of new specimens, morphometric analyses, and use of CT-scan, when feasible.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"693 - 710"},"PeriodicalIF":1.4,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43378804","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. Trilobites from the upper Guzhangian of the southern Argentine Precordillera, preliminarily described by Carlos Rusconi in the 1950s, are revised herein. The specimens studied were collected from an allochthonous limestone block of La Cruz Olistoliths at 200 m northwest of Estancia San Isidro locality (San Isidro area, Mendoza). Taxa comprise Kormagnostus seclusus (Walcott, 1884), Cedaria prolifica Walcott, 1924, C. puelchana Rusconi, 1954, Tricrepicephalus texanus (Shumard, 1861), Meteoraspis metra (Walcott, 1890), Coosia conicephala (Rusconi, 1954) new combination, Coosella texana? Resser, 1942, Nasocephalus cf. N. nasutus Wilson, 1954, and Olenoides proa (Rusconi, 1954) new combination. The North American genera Meteoraspis Resser, 1935 and Nasocephalus Wilson, 1954 are reported confidently from South America for the first time. This assemblage is representative of the Cedaria prolifica Zone, which correlates with the lower Crepicephalus Zone of the traditional North American genus-based zonation. Most of the genera and species identified were previously described exclusively from Canada, the United States, and northwestern Mexico, a fact that provides new support to an allochthonous Laurentian origin of the Argentine Precordillera.
{"title":"Trilobites from the Cedaria prolifica Zone (Cambrian, upper Guzhangian) of the Precordillera of Mendoza, western Argentina","authors":"M. F. Tortello","doi":"10.1017/jpa.2023.34","DOIUrl":"https://doi.org/10.1017/jpa.2023.34","url":null,"abstract":"Abstract. Trilobites from the upper Guzhangian of the southern Argentine Precordillera, preliminarily described by Carlos Rusconi in the 1950s, are revised herein. The specimens studied were collected from an allochthonous limestone block of La Cruz Olistoliths at 200 m northwest of Estancia San Isidro locality (San Isidro area, Mendoza). Taxa comprise Kormagnostus seclusus (Walcott, 1884), Cedaria prolifica Walcott, 1924, C. puelchana Rusconi, 1954, Tricrepicephalus texanus (Shumard, 1861), Meteoraspis metra (Walcott, 1890), Coosia conicephala (Rusconi, 1954) new combination, Coosella texana? Resser, 1942, Nasocephalus cf. N. nasutus Wilson, 1954, and Olenoides proa (Rusconi, 1954) new combination. The North American genera Meteoraspis Resser, 1935 and Nasocephalus Wilson, 1954 are reported confidently from South America for the first time. This assemblage is representative of the Cedaria prolifica Zone, which correlates with the lower Crepicephalus Zone of the traditional North American genus-based zonation. Most of the genera and species identified were previously described exclusively from Canada, the United States, and northwestern Mexico, a fact that provides new support to an allochthonous Laurentian origin of the Argentine Precordillera.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"591 - 605"},"PeriodicalIF":1.4,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46623790","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. Nine crinoids are described from the Wooster Shale Member of the Cuyahoga Formation from Wayne and Ashland counties, Ohio, USA. Identifiable elements of the fauna include five camerate crinoids, one flexible crinoid, and three other eucladid crinoids. Five new species are described, including Cactocrinus woosterensis n. sp., Cusacrinus brushi n. sp., Agaricocrinus murphyi n. sp., Decadocrinus laevis n. sp., and Decadocrinus inordinatus n. sp. Overall, the distribution of crinoid clades in the Wooster Shale is similar to that of the stratigraphically lower Meadville Shale Member of the Cuyahoga Formation, although less diverse and with only one species (Cyathocrinites simplex) in common. Many of the Wooster Shale Member crinoids are completely or partially preserved with siderite either in nodules or within siderite beds. These crinoids are commonly preserved in trauma postures, which is characteristic of burial in episodic high turbulence events. The paleoenvironments and taxa of the two Cuyahoga Formation crinoid faunas more closely resemble Viséan faunas in siliciclastic settings than typical carbonate faunas of the Tournaisian.
{"title":"Crinoids from the Wooster Shale Member of the Cuyahoga Formation, Carboniferous (Mississippian, Tournaisian) of northeastern Ohio","authors":"W. Ausich, Mark A. Wilson","doi":"10.1017/jpa.2023.20","DOIUrl":"https://doi.org/10.1017/jpa.2023.20","url":null,"abstract":"Abstract. Nine crinoids are described from the Wooster Shale Member of the Cuyahoga Formation from Wayne and Ashland counties, Ohio, USA. Identifiable elements of the fauna include five camerate crinoids, one flexible crinoid, and three other eucladid crinoids. Five new species are described, including Cactocrinus woosterensis n. sp., Cusacrinus brushi n. sp., Agaricocrinus murphyi n. sp., Decadocrinus laevis n. sp., and Decadocrinus inordinatus n. sp. Overall, the distribution of crinoid clades in the Wooster Shale is similar to that of the stratigraphically lower Meadville Shale Member of the Cuyahoga Formation, although less diverse and with only one species (Cyathocrinites simplex) in common. Many of the Wooster Shale Member crinoids are completely or partially preserved with siderite either in nodules or within siderite beds. These crinoids are commonly preserved in trauma postures, which is characteristic of burial in episodic high turbulence events. The paleoenvironments and taxa of the two Cuyahoga Formation crinoid faunas more closely resemble Viséan faunas in siliciclastic settings than typical carbonate faunas of the Tournaisian.","PeriodicalId":50098,"journal":{"name":"Journal of Paleontology","volume":"97 1","pages":"652 - 674"},"PeriodicalIF":1.4,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42653240","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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