Abstract. Marine planktonic diatoms, as today's ocean main carbon and silicon exporters, are central to developing an understanding of the interplay between the evolution of marine life and climate change. The diatom fossil record extends as far as the Early Cretaceous, and the late Paleogene to Recent interval is relatively complete and well documented. Their early Paleogene record, when diatoms first expanded substantially in the marine plankton, is hampered by decreased preservation (notably an episode of intense chertification in the early Eocene) as well as by observation bias. In this article, we attempt to correct for the latter by collecting diatom data in various Paleocene samples from legacy Deep Sea Drilling Project and Ocean Drilling Program deep-sea sediment sections. The results show a different picture from what previous analyses concluded, in that the Paleocene deep-sea diatoms seem in fact to have been as diverse and abundant as in the later Eocene, while exhibiting very substantial survivorship of Cretaceous species up until the Eocene.
{"title":"The Paleocene record of marine diatoms in deep-sea sediments","authors":"J. Renaudie, Effi-Laura Drews, S. Böhne","doi":"10.5194/FR-21-183-2018","DOIUrl":"https://doi.org/10.5194/FR-21-183-2018","url":null,"abstract":"Abstract. Marine planktonic diatoms, as today's ocean main carbon and silicon exporters, are central to developing an understanding of the interplay between the evolution of marine life and climate change. The diatom fossil record extends as far as the Early Cretaceous, and the late Paleogene to Recent interval is relatively complete and well documented. Their early Paleogene record, when diatoms first expanded substantially in the marine plankton, is hampered by decreased preservation (notably an episode of intense chertification in the early Eocene) as well as by observation bias. In this article, we attempt to correct for the latter by collecting diatom data in various Paleocene samples from legacy Deep Sea Drilling Project and Ocean Drilling Program deep-sea sediment sections. The results show a different picture from what previous analyses concluded, in that the Paleocene deep-sea diatoms seem in fact to have been as diverse and abundant as in the later Eocene, while exhibiting very substantial survivorship of Cretaceous species up until the Eocene.","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2018-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43838672","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. Body size changes have been reported across crisis intervals. Belemnites – now considered extinct stem-decabrachians – have rarely been investigated for this purpose, and the few studies have resulted in ambiguous outcomes. Here we investigate two Toarcian belemnite accumulations in southern Germany from a morphometric point of view with the support of computed tomography data. The aim of this study is to test whether a difference in size can be observed between the rostra of the two studied samples, from individual lineage to community, and which proxy is more reliable. A significant decrease in median size from the Early Toarcian (Dactylioceras tenuicostatum Zone) to the Middle Toarcian (Haugia variabilis Zone) is recognized. This is observed at the community level of organization, considering the whole assemblage, but also within Passaloteuthis–Acrocoelites lineage, at the genus level. It is also demonstrated that diameter-based measurements or maximum preserved length are not reliable proxies for size, and therefore apical length or three-dimensional approximations, such as the geometric mean or the post-phragmocone volume, are more advisable. This is especially important when comparing specimens with markedly different rostrum shapes. Further studies are, however, still necessary to disentangle the mechanisms behind the reduction in rostrum size within the Toarcian and their putative environmental causes.
{"title":"Rostrum size differences between Toarcian belemnite battlefields","authors":"Patrícia Rita, K. De Baets, M. Schlott","doi":"10.5194/FR-21-171-2018","DOIUrl":"https://doi.org/10.5194/FR-21-171-2018","url":null,"abstract":"Abstract. Body size changes have been reported across crisis intervals. Belemnites – now considered extinct stem-decabrachians – have rarely been investigated for this purpose, and the few studies have resulted in ambiguous outcomes. Here we investigate two Toarcian belemnite accumulations in southern Germany from a morphometric point of view with the support of computed tomography data. The aim of this study is to test whether a difference in size can be observed between the rostra of the two studied samples, from individual lineage to community, and which proxy is more reliable. A significant decrease in median size from the Early Toarcian (Dactylioceras tenuicostatum Zone) to the Middle Toarcian (Haugia variabilis Zone) is recognized. This is observed at the community level of organization, considering the whole assemblage, but also within Passaloteuthis–Acrocoelites lineage, at the genus level. It is also demonstrated that diameter-based measurements or maximum preserved length are not reliable proxies for size, and therefore apical length or three-dimensional approximations, such as the geometric mean or the post-phragmocone volume, are more advisable. This is especially important when comparing specimens with markedly different rostrum shapes. Further studies are, however, still necessary to disentangle the mechanisms behind the reduction in rostrum size within the Toarcian and their putative environmental causes.\u0000","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2018-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48127256","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}
P. Skutschas, V. Kolchanov, E. Boitsova, I. Kuzmin
Abstract. Osseous anomalies/pathologies in the Late Cretaceous cryptobranchid salamander Eoscapherpeton asiaticum from the Turonian Bissekty Formation of Uzbekistan are analyzed using gross morphological description, microCT, and histologic analysis. These pathologies result from trauma (fractured and subsequently healed dentary and femora; hematoma on femur), possible infection due to trauma (prearticular with exostosis and necrotic cavities; anterior trunk vertebra and fused vertebra with pathological enlargements formed during reactive periosteal growth) and congenital disorders (hemivertebra and fused vertebrae with shortened asymmetrical centra and abnormal arrangements of transverse processes). The origin of the pathologies of two atlantal specimens (enlargement of transverse processes) is unclear. Our report of hemivertebra in Eoscapherpeton is the first occurrence of this congenital pathology in a fossil lissamphibian. The occurrence of several traumatic femoral pathologies in Eoscapherpeton could be a result of intraspecific aggressive behavior. Bone pathologies are described for the first time in fossil salamanders.
{"title":"Osseous anomalies of the cryptobranchid Eoscapherpeton asiaticum (Amphibia: Caudata) from the Late Cretaceous of Uzbekistan","authors":"P. Skutschas, V. Kolchanov, E. Boitsova, I. Kuzmin","doi":"10.5194/FR-21-159-2018","DOIUrl":"https://doi.org/10.5194/FR-21-159-2018","url":null,"abstract":"Abstract. Osseous anomalies/pathologies in the Late Cretaceous cryptobranchid\u0000salamander Eoscapherpeton asiaticum from the Turonian\u0000Bissekty Formation of Uzbekistan are\u0000analyzed using gross morphological description, microCT, and histologic\u0000analysis. These pathologies result from\u0000trauma (fractured and subsequently healed dentary and femora; hematoma on\u0000femur), possible infection due to trauma (prearticular with exostosis and\u0000necrotic cavities; anterior trunk vertebra and fused vertebra with\u0000pathological enlargements formed during reactive periosteal growth) and\u0000congenital disorders (hemivertebra and fused vertebrae with shortened\u0000asymmetrical centra and abnormal arrangements of transverse processes). The\u0000origin of the pathologies of two atlantal specimens (enlargement of\u0000transverse processes) is unclear. Our report of hemivertebra in\u0000Eoscapherpeton is the first occurrence of this congenital pathology\u0000in a fossil lissamphibian. The occurrence of several traumatic femoral\u0000pathologies in Eoscapherpeton could be a result of intraspecific\u0000aggressive behavior. Bone pathologies are described for the first time in\u0000fossil salamanders.","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":"21 1","pages":"159-169"},"PeriodicalIF":1.4,"publicationDate":"2018-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45979959","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. Bone tissue, microanatomy, and growth are studied in humeri of the pachypleurosaurs Dactylosaurus from the early Anisian of Poland and of aff. Neusticosaurus pusillus from the Lettenkeuper (early Ladinian) of southern Germany. Histology and modeled growth curves are compared to already published data of other pachypleurosaurs. Therefore, we herein established growth curves for Anarosaurus from the middle Anisian of Winterswijk (the Netherlands) and for pachypleurosaurs from the Anisian/Ladinian of the Alpine Triassic (i.e., Neusticosaurus spp. and Serpianosaurus). Humeri of Dactylosaurus, Anarosaurus, and aff. N. pusillus, all from the Germanic Basin, usually display an inner ring of (pre-)hatchling bone tissue. In some samples this tissue is surrounded by a layer of perpendicularly oriented fine fibers, which could indicate the start of active locomotion for foraging or might be related to viviparity. However, pachypleurosaurs from the Alpine Triassic do not show this tissue. This in turn could be related to overall differences in the environments inhabited (Germanic Basin vs. Alpine Triassic). Histological comparison revealed distinct taxon-specific differences in microanatomy and bone tissue type between Anarosaurus on the one hand and Dactylosaurus and the Neusticosaurus–Serpianosaurus clade on the other hand. Microanatomical differences imply a different degree in secondary adaptation to an aquatic environment. Life-history traits derived histologically and obtained from modeling growth were in general rather similar for all studied pachypleurosaurs. Onset of sexual maturation was within the first third of life. Asymptotic ages (maximum life span) considerably exceeded documented and modeled ages at death in all pachypleurosaur taxa. All traits modeled (more or less) matched values seen in similar-sized extant reptiles. Growth curves revealed differences in growth and maturation strategies within taxa that could indicate sexual dimorphism expressed in different adult sizes and a different onset of sexual maturation. Differences in gender size and morphology is well documented for the Chinese pachypleurosaur Keichousaurus and for Neusticosaurus spp. from the Alpine Triassic. Birth-to-adult size ratios of herein studied pachypleurosaurs were consistent with those seen in other viviparous Sauropterygia, other viviparous extinct taxa as well as extant viviparous reptiles. Anarosaurus had the highest maximum growth rates of all pachypleurosaurs studied, which best conformed to those seen in today's similar-sized reptiles and is expected from its bone tissue type. The other pachypleurosaur taxa had lower rates than the average seen in similar-sized extant reptiles. We hypothesize from our data that the considerably higher asymptotic ages compared to ages at death, early onset of maturation compared to asymptotic age, and viviparity reflect that pachypleurosaurs lived in predator-dominated environments.
{"title":"Growth patterns, sexual dimorphism, and maturation modeled in Pachypleurosauria from Middle Triassic of central Europe (Diapsida: Sauropterygia)","authors":"N. Klein, E. Griebeler","doi":"10.5194/FR-21-137-2018","DOIUrl":"https://doi.org/10.5194/FR-21-137-2018","url":null,"abstract":"Abstract. Bone tissue, microanatomy, and growth are studied in humeri of the\u0000pachypleurosaurs Dactylosaurus from the early Anisian of Poland and of\u0000aff. Neusticosaurus pusillus from the Lettenkeuper (early Ladinian) of\u0000southern Germany. Histology and modeled growth curves are compared to\u0000already published data of other pachypleurosaurs. Therefore, we herein established growth curves for Anarosaurus from the middle Anisian of\u0000Winterswijk (the Netherlands) and for pachypleurosaurs from the Anisian/Ladinian of\u0000the Alpine Triassic (i.e., Neusticosaurus spp. and\u0000Serpianosaurus). Humeri of Dactylosaurus,\u0000Anarosaurus, and aff. N. pusillus, all from the Germanic\u0000Basin, usually display an inner ring of (pre-)hatchling bone tissue. In some\u0000samples this tissue is surrounded by a layer of perpendicularly oriented fine\u0000fibers, which could indicate the start of active locomotion for foraging or\u0000might be related to viviparity. However, pachypleurosaurs from the Alpine\u0000Triassic do not show this tissue. This in turn could be related to overall\u0000differences in the environments inhabited (Germanic Basin vs. Alpine\u0000Triassic). Histological comparison revealed distinct taxon-specific\u0000differences in microanatomy and bone tissue type between Anarosaurus\u0000on the one hand and Dactylosaurus and the\u0000Neusticosaurus–Serpianosaurus clade on the other hand.\u0000Microanatomical differences imply a different degree in secondary\u0000adaptation to an aquatic environment. Life-history traits derived histologically and obtained from modeling growth\u0000were in general rather similar for all studied pachypleurosaurs. Onset of\u0000sexual maturation was within the first third of life. Asymptotic ages\u0000(maximum life span) considerably exceeded documented and modeled ages at\u0000death in all pachypleurosaur taxa. All traits modeled (more or less) matched values seen in similar-sized extant reptiles. Growth curves revealed\u0000differences in growth and maturation strategies within taxa that could\u0000indicate sexual dimorphism expressed in different adult sizes and a different\u0000onset of sexual maturation. Differences in gender size and morphology is well\u0000documented for the Chinese pachypleurosaur Keichousaurus and for\u0000Neusticosaurus spp. from the Alpine Triassic. Birth-to-adult size\u0000ratios of herein studied pachypleurosaurs were consistent with those seen in\u0000other viviparous Sauropterygia, other viviparous extinct taxa as well as extant\u0000viviparous reptiles. Anarosaurus had the highest maximum growth\u0000rates of all pachypleurosaurs studied, which best conformed to those seen in\u0000today's similar-sized reptiles and is expected from its bone tissue type. The\u0000other pachypleurosaur taxa had lower rates than the average seen in\u0000similar-sized extant reptiles. We hypothesize from our data that the considerably higher asymptotic ages\u0000compared to ages at death, early onset of maturation compared to asymptotic\u0000age, and viviparity reflect that pachypleurosaurs lived in predator-dominated\u0000environments.","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":"21 1","pages":"137-157"},"PeriodicalIF":1.4,"publicationDate":"2018-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48210600","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. Algorachelus peregrinus is the oldest representative of the crown group Pleurodira known in Laurasia. The type locality of this bothremydid is Algora, situated in central Spain, at levels deposited during the uppermost middle–lowermost upper Cenomanian. A new excavation was recently carried out in this town. As a result, abundant material of Algorachelus peregrinus has been found. Several complete shells, as well as numerous partial carapaces and plastra, are presented here. The abundance of remains allows the analysis of the general patterns by which some of the shells of this littoral form were partially or totally disarticulated. The analysis of these remains not only shows several pathologies but also improves the knowledge about the anatomy and intraspecific variability of Algorachelus peregrinus. This new information allows the revision of other Cenomanian forms of Bothremydidae, both from the Middle East and from North America. Thus, Algorachelus is identified in these regions, being represented in the early or middle Cenomanian of Palestine by the new combination Algorachelus parvus, and in the uppermost Cenomanian of Utah by the new combination Algorachelus tibert. Therefore, a relatively fast and widely distributed geographic dispersion event is recognized, corresponding to the oldest dispersal event so far identified for a lineage of Pleurodira from Gondwana to Laurasia.
{"title":"New information on the Cenomanian bothremydid turtle Algorachelus based on new, well-preserved material from Spain","authors":"A. Pérez‐García","doi":"10.5194/FR-21-119-2018","DOIUrl":"https://doi.org/10.5194/FR-21-119-2018","url":null,"abstract":"Abstract. Algorachelus peregrinus is the oldest representative of the crown\u0000group Pleurodira known in Laurasia. The type locality of this bothremydid is\u0000Algora, situated in central Spain, at levels deposited during the uppermost\u0000middle–lowermost upper\u0000Cenomanian. A new excavation was recently carried out in this town. As a\u0000result, abundant material of Algorachelus peregrinus has been found.\u0000Several complete shells, as well as numerous partial carapaces and plastra,\u0000are presented here. The abundance of remains allows the analysis of the\u0000general patterns by which some of the shells of this littoral form were\u0000partially or totally disarticulated. The analysis of these remains not only\u0000shows several pathologies but also improves the knowledge about the anatomy\u0000and intraspecific variability of Algorachelus peregrinus. This new\u0000information allows the revision of other Cenomanian forms of Bothremydidae,\u0000both from the Middle East and from North America. Thus, Algorachelus\u0000is identified in these regions, being represented in the early or middle\u0000Cenomanian of Palestine by the new combination Algorachelus parvus,\u0000and in the uppermost Cenomanian of Utah by the new combination\u0000Algorachelus tibert. Therefore, a relatively fast and widely\u0000distributed geographic dispersion event is recognized, corresponding to the\u0000oldest dispersal event so far identified for a lineage of Pleurodira from\u0000Gondwana to Laurasia.","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":"21 1","pages":"119-135"},"PeriodicalIF":1.4,"publicationDate":"2018-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45986236","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. Ontogenetic series of extinct taxa are rare. However, if preserved, fossil embryos and juveniles can provide evidence of developmental plasticity as related to ecological specialization. Here, we describe articulated and isolated juvenile material found in close association with an adult mesosaurid Stereosternum tumidum (MB.R.2089) from Lower Permian sediments in Brazil, housed in the collection of the Museum fur Naturkunde Berlin. Stylopodial, zeugopodial, and autopodial elements are not yet completely ossified in the juveniles, as indicated by compression artifacts on the surface of the bone. These correspond to internal ossification processes, which have been demonstrated in other aquatic taxa. Quantitative analysis of measurements in juvenile and adult material reveals differing growth rates between limb elements: hind limb zeugopodia, which are massive and elongate in the adult as needed for propulsion, are already comparatively larger in the juvenile than the humeri, femora, and also the zeugopodia of the forelimb. This pattern differs from that seen in another extinct aquatic reptile, Hovasaurus boulei. Nevertheless, we attribute the accelerated growth rate or earlier onset of ossification to be a potential developmental pathway generating limb element variation in the adult present in 280 million year old mesosaurs, which are known for their fully aquatic lifestyle, in which the hind limbs play a more prominent role than the forelimbs.
{"title":"A case study of developmental palaeontology in Stereosternum tumidum (Mesosauridae, Parareptilia)","authors":"C. Bickelmann, L. A. Tsuji","doi":"10.5194/FR-21-109-2018","DOIUrl":"https://doi.org/10.5194/FR-21-109-2018","url":null,"abstract":"Abstract. Ontogenetic series of extinct taxa are rare. However, if preserved, fossil\u0000embryos and juveniles can provide evidence of developmental plasticity as\u0000related to ecological specialization. Here, we describe articulated and\u0000isolated juvenile material found in close association with an adult\u0000mesosaurid Stereosternum tumidum (MB.R.2089) from Lower Permian\u0000sediments in Brazil, housed in the collection of the Museum fur\u0000Naturkunde Berlin. Stylopodial, zeugopodial, and autopodial elements are not\u0000yet completely ossified in the juveniles, as indicated by compression\u0000artifacts on the surface of the bone. These correspond to internal\u0000ossification processes, which have been demonstrated in other aquatic taxa.\u0000Quantitative analysis of measurements in juvenile and adult material reveals\u0000differing growth rates between limb elements: hind limb zeugopodia, which are\u0000massive and elongate in the adult as needed for propulsion, are already\u0000comparatively larger in the juvenile than the humeri, femora, and also the\u0000zeugopodia of the forelimb. This pattern differs from that seen in another\u0000extinct aquatic reptile, Hovasaurus boulei. Nevertheless, we\u0000attribute the accelerated growth rate or earlier onset of ossification to be\u0000a potential developmental pathway generating limb element variation in the\u0000adult present in 280 million year old mesosaurs, which are known for their\u0000fully aquatic lifestyle, in which the hind limbs play a more prominent role\u0000than the forelimbs.","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":"21 1","pages":"109-118"},"PeriodicalIF":1.4,"publicationDate":"2018-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47208661","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}
G. Arratia, K. González-Rodríguez, Citlalli Hernández-Guerrero, Citlalli Hernández-Guerrero
Abstract. A new genus and species – Motlayoichthys sergioi (ZooBank registration: urn:lsid:zoobank.org:pub:2C503741-2362-4234-8CE0-BB7D8BE5A236, urn:lsid:zoobank.org:act:EF5040FD-F306-4C0F-B9DA-2CC696CA349D) – from the Cretaceous (Albian-Cenomanian) of the Muhi Quarry, Hidalgo, central Mexico is assigned to the family Pachyrhizodontidae based on the presence of the inner premaxillary tooth and a few other cranial characters. Its unique suite of characters, that includes several autapomorphies supports its assignment as a new genus and species, such as the presence of a triangular head with three sides of similar lengths and with its deepest part at the level of the supraoccipital region; the lower jaw projecting anterior to the premaxilla; the ornamentation of cranial bones – especially those of the cheek region – consisting of fine longitudinal crests densely covering the bony surfaces; one or a few deep grooves on the mandibular teeth, which in addition bear acrodin tips ornamented with fine parallel striae; and the position of the dorsal fin, near the posterior margin of the cranium. Motlayoichthys n. gen., together with Michin, Pachyrhizodus, Rhacolepis, and Notelops, is part of the early radiation of pachyrhizodontoids during Albian times.
摘要墨西哥中部伊达尔戈Muhi Quarry白垩纪(Albian-Cenomanian)的一种新属和新种——Motlayoichthys sergioi (ZooBank注册:urn:lsid:zoobank.org:pub:2C503741-2362-4234-8CE0-BB7D8BE5A236, urn:lsid:zoobank.org:act:EF5040FD-F306-4C0F-B9DA-2CC696CA349D)，基于上颌前内齿的存在和其他一些颅骨特征被分配到Pachyrhizodontidae科。它独特的一套特征，包括几个自异形，支持了它作为一个新属和新种的分配，如三角形头部的存在，三条边的长度相似，其最深的部分在枕上区域的水平;上颌骨前突出的下颚;头盖骨的纹饰，尤指脸颊区域的头盖骨，由浓密地覆盖在骨表面的细的纵向嵴组成;在下颚齿上的一个或几个深凹槽，其另外具有尖尖的尖齿，装饰有细的平行条纹;还有背鳍的位置，靠近颅骨的后缘。Motlayoichthys n. gen.与Michin, Pachyrhizodus, Rhacolepis和Notelops一起，是Albian时期早期pachyrhizzodontoids辐射的一部分。
{"title":"A new pachyrhizodontid fish (Actinopterygii, Teleostei) from the Muhi Quarry (Albian-Cenomanian), Hidalgo, Mexico","authors":"G. Arratia, K. González-Rodríguez, Citlalli Hernández-Guerrero, Citlalli Hernández-Guerrero","doi":"10.5194/FR-21-93-2018","DOIUrl":"https://doi.org/10.5194/FR-21-93-2018","url":null,"abstract":"Abstract. A new genus and species – Motlayoichthys sergioi (ZooBank registration: urn:lsid:zoobank.org:pub:2C503741-2362-4234-8CE0-BB7D8BE5A236, urn:lsid:zoobank.org:act:EF5040FD-F306-4C0F-B9DA-2CC696CA349D) – from the Cretaceous (Albian-Cenomanian) of the Muhi Quarry, Hidalgo, central Mexico is assigned to the family Pachyrhizodontidae based on the presence of the inner premaxillary tooth and a few other cranial characters. Its unique suite of characters, that includes several autapomorphies supports its assignment as a new genus and species, such as the presence of a triangular head with three sides of similar lengths and with its deepest part at the level of the supraoccipital region; the lower jaw projecting anterior to the premaxilla; the ornamentation of cranial bones – especially those of the cheek region – consisting of fine longitudinal crests densely covering the bony surfaces; one or a few deep grooves on the mandibular teeth, which in addition bear acrodin tips ornamented with fine parallel striae; and the position of the dorsal fin, near the posterior margin of the cranium. Motlayoichthys n. gen., together with Michin, Pachyrhizodus, Rhacolepis, and Notelops, is part of the early radiation of pachyrhizodontoids during Albian times.","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":"21 1","pages":"93-107"},"PeriodicalIF":1.4,"publicationDate":"2018-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48026452","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 early Permian karst system near Richards Spur, Oklahoma preserves a diverse assemblage of terrestrial dissorophoid temnospondyls. Here we report the presence of a large-bodied dissorophine dissorophid that is represented by an articulated anterior trunk region, including a partial pectoral girdle, a ribcage characterized by extremely developed uncinate processes, and a rare, completely articulated pes. This represents the first documentation of the clade at the locality. Previously, dissorophids were represented only by the eucacopine Cacops. A complete pelvic girdle with hindlimbs is also referred to Cacops and represents the first material of the posterior trunk region to be described from the genus at Richards Spur. These specimens expand the taxonomic diversity known from the site and provide significant, well-preserved postcranial material that improves the characterization of dissorophid postcranial anatomy.
{"title":"Postcrania of large dissorophid temnospondyls from Richards Spur, Oklahoma","authors":"B. Gee, R. Reisz","doi":"10.5194/FR-21-79-2018","DOIUrl":"https://doi.org/10.5194/FR-21-79-2018","url":null,"abstract":"Abstract. The early Permian karst system near Richards Spur, Oklahoma preserves a diverse\u0000assemblage of terrestrial dissorophoid temnospondyls. Here we report the\u0000presence of a large-bodied dissorophine dissorophid that is represented by an\u0000articulated anterior trunk region, including a partial pectoral girdle, a\u0000ribcage characterized by extremely developed uncinate processes, and a rare,\u0000completely articulated pes. This represents the first documentation of the\u0000clade at the locality. Previously, dissorophids were represented only by the\u0000eucacopine Cacops. A complete pelvic girdle with hindlimbs is also referred to Cacops\u0000and represents the first material of the posterior trunk region to be\u0000described from the genus at Richards Spur. These specimens expand the\u0000taxonomic diversity known from the site and provide significant,\u0000well-preserved postcranial material that improves the characterization of\u0000dissorophid postcranial anatomy.","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":"57 11","pages":"79-91"},"PeriodicalIF":1.4,"publicationDate":"2018-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41257669","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. Selected specimens from the Jurassic ammonoid family Arietitidae were investigated using morphometric methods of transverse and longitudinal conch section analysis. The family Arietitidae is characterized by similarities in the conch geometry, but variation can be demonstrated by means of differences in conch morphology. Our study focuses on a specimen of the arietitid Pararnioceras sp., which revealed striking changes in conch morphology due to a syn vivo growth through a parasitic serpulid. Changes in its ontogenetic development are compared with specimens without epizoans. The ecological interpretation of the morphometric data allows the conclusion that the host possessed the ability to counteract the parasitic conch abnormalities by adapting its housing growth, thus ensuring survival.
{"title":"Morphology of the Early Jurassic Arietitidae and the effects of syn vivo serpulid infestations","authors":"M. Ramming, D. Korn, C. Klein, C. Klug","doi":"10.5194/FR-21-67-2018","DOIUrl":"https://doi.org/10.5194/FR-21-67-2018","url":null,"abstract":"Abstract. Selected specimens from the Jurassic ammonoid family Arietitidae were\u0000investigated using morphometric methods of transverse and longitudinal conch\u0000section analysis. The family Arietitidae is characterized by similarities in\u0000the conch geometry, but variation can be demonstrated by means of\u0000differences in conch morphology. Our study focuses on a specimen of the\u0000arietitid Pararnioceras sp., which revealed striking changes in\u0000conch morphology due to a syn vivo growth through a parasitic serpulid.\u0000Changes in its ontogenetic development are compared with specimens without\u0000epizoans. The ecological interpretation of the morphometric data allows the\u0000conclusion that the host possessed the ability to counteract the parasitic\u0000conch abnormalities by adapting its housing growth, thus ensuring\u0000survival.","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":"21 1","pages":"67-77"},"PeriodicalIF":1.4,"publicationDate":"2018-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48655695","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. Fossil biting traces (praedichnia) represent indirect evidence of predation and shed light on fossil predator–prey interactions and fossil food webs. Especially from echinoderm skeletons, biting traces are well known. Here, we describe the oral surface of a large Cretaceous (Maastrichtian) holasteroid echinoid Echinocorys ovata Leske, 1778 from Hemmoor (northern Germany) which exhibits four circular punctures arranged in a semi-circular arc. Whereas three of the punctures penetrated the skeleton, one puncture only just hit the margin of the echinoid test at the ambitus, leaving a long incision furrow in the skeleton. The punctures were not lethal to the sea urchin as is indicated by progressed skeletal regeneration and closure of the fractures. The overall appearance of the punctures suggests that they were produced during a single mechanical event, most likely by the biting action of the teeth of a large vertebrate animal. We analysed the shape and arrangement of the biting trace and conclude that it was probably produced by a marine reptile possessing a prognath tooth position, most likely by a globidensine mosasauroid. Our finding not only sheds light on mosasaur feeding behaviour and prey selection but also increases the knowledge of the food webs in the chalk sea ecosystem during the uppermost Cretaceous.
{"title":"Eggs for breakfast? Analysis of a probable mosasaur biting trace on the Cretaceous echinoid Echinocorys ovata Leske, 1778","authors":"C. Neumann, O. Hampe","doi":"10.5194/FR-21-55-2018","DOIUrl":"https://doi.org/10.5194/FR-21-55-2018","url":null,"abstract":"Abstract. Fossil biting traces (praedichnia) represent indirect evidence of predation\u0000and shed light on fossil predator–prey interactions and fossil food webs.\u0000Especially from echinoderm skeletons, biting traces are well known. Here, we\u0000describe the oral surface of a large Cretaceous (Maastrichtian) holasteroid\u0000echinoid Echinocorys ovata Leske, 1778 from Hemmoor (northern Germany) which exhibits\u0000four circular punctures arranged in a semi-circular arc. Whereas\u0000three of the punctures penetrated the skeleton, one puncture only just hit\u0000the margin of the echinoid test at the ambitus, leaving a long incision\u0000furrow in the skeleton. The punctures were not lethal to the sea urchin as is\u0000indicated by progressed skeletal regeneration and closure of the fractures.\u0000The overall appearance of the punctures suggests that they were produced\u0000during a single mechanical event, most likely by the biting action of the\u0000teeth of a large vertebrate animal. We analysed the shape and arrangement of\u0000the biting trace and conclude that it was probably produced by a marine\u0000reptile possessing a prognath tooth position, most likely by a globidensine\u0000mosasauroid. Our finding not only sheds light on mosasaur feeding behaviour\u0000and prey selection but also increases the knowledge of the food webs in the chalk sea\u0000ecosystem during the uppermost Cretaceous.","PeriodicalId":48830,"journal":{"name":"Fossil Record","volume":"21 1","pages":"55-66"},"PeriodicalIF":1.4,"publicationDate":"2018-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48935828","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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