Julien Louys, M. Duval, R. Beck, Eleanor M. A. Pease, Ian Sobbe, Noel Sands, G. Price
{"title":"澳大利亚晚更新世大袋熊(Ramsayia magna)颅骨遗存与袋熊巨人症的进化(有袋目,袋熊科)","authors":"Julien Louys, M. Duval, R. Beck, Eleanor M. A. Pease, Ian Sobbe, Noel Sands, G. Price","doi":"10.1002/spp2.1475","DOIUrl":null,"url":null,"abstract":"Giant wombats (defined here as ≥70 kg) are found in the genera Phascolonus, Ramsayia and perhaps Sedophascolomys. Ramsayia is currently the most poorly known, having been described from mandibular and cranial fragments. Here, we report the most complete cranial remains attributable to the genus, identified as R. magna. The specimen provides new insights into the anatomy of the species and evolutionary adaptations to gigantism in Vombatidae. We record parietal sinuses in a vombatid for the first time, an adaptation to increased skull size relative to the braincase. The presence of a prominent premaxillary spine may indicate that the species possessed a large, fleshy nose. Both features are convergent on other large‐bodied, non‐vombatid extinct megaherbivores of Australia such as Diprotodon optatum. We use the cranial remains to examine the phylogenetic relationships of giant wombats to other vombatids. Phylogenetic analysis using maximum parsimony and Bayesian inference indicates that Phascolomys, Ramsayia and Sedophascolomys form a clade, suggesting a single origin of gigantism within Vombatidae. This origin may be related to the exploitation of poor‐quality foods, and preceded extreme specializations observed in the cranial anatomy of the giant wombats. U‐series and combined U‐series and electron spin resonance (ESR) dating methods were applied to one fossil tooth. Age calculations systematically correlate the fossil remains to Marine Isotope Stage 5, and an age of c. 80 000 years can be proposed for this specimen. With only a single well‐dated occurrence for this taxon, it is currently impossible to determine when and why R. magna became extinct.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.3000,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Cranial remains of Ramsayia magna from the Late Pleistocene of Australia and the evolution of gigantism in wombats (Marsupialia, Vombatidae)\",\"authors\":\"Julien Louys, M. Duval, R. Beck, Eleanor M. A. Pease, Ian Sobbe, Noel Sands, G. Price\",\"doi\":\"10.1002/spp2.1475\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Giant wombats (defined here as ≥70 kg) are found in the genera Phascolonus, Ramsayia and perhaps Sedophascolomys. Ramsayia is currently the most poorly known, having been described from mandibular and cranial fragments. Here, we report the most complete cranial remains attributable to the genus, identified as R. magna. The specimen provides new insights into the anatomy of the species and evolutionary adaptations to gigantism in Vombatidae. We record parietal sinuses in a vombatid for the first time, an adaptation to increased skull size relative to the braincase. The presence of a prominent premaxillary spine may indicate that the species possessed a large, fleshy nose. Both features are convergent on other large‐bodied, non‐vombatid extinct megaherbivores of Australia such as Diprotodon optatum. We use the cranial remains to examine the phylogenetic relationships of giant wombats to other vombatids. Phylogenetic analysis using maximum parsimony and Bayesian inference indicates that Phascolomys, Ramsayia and Sedophascolomys form a clade, suggesting a single origin of gigantism within Vombatidae. This origin may be related to the exploitation of poor‐quality foods, and preceded extreme specializations observed in the cranial anatomy of the giant wombats. U‐series and combined U‐series and electron spin resonance (ESR) dating methods were applied to one fossil tooth. Age calculations systematically correlate the fossil remains to Marine Isotope Stage 5, and an age of c. 80 000 years can be proposed for this specimen. With only a single well‐dated occurrence for this taxon, it is currently impossible to determine when and why R. magna became extinct.\",\"PeriodicalId\":48705,\"journal\":{\"name\":\"Papers in Palaeontology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.3000,\"publicationDate\":\"2022-11-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Papers in Palaeontology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1002/spp2.1475\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"PALEONTOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Papers in Palaeontology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1002/spp2.1475","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PALEONTOLOGY","Score":null,"Total":0}
Cranial remains of Ramsayia magna from the Late Pleistocene of Australia and the evolution of gigantism in wombats (Marsupialia, Vombatidae)
Giant wombats (defined here as ≥70 kg) are found in the genera Phascolonus, Ramsayia and perhaps Sedophascolomys. Ramsayia is currently the most poorly known, having been described from mandibular and cranial fragments. Here, we report the most complete cranial remains attributable to the genus, identified as R. magna. The specimen provides new insights into the anatomy of the species and evolutionary adaptations to gigantism in Vombatidae. We record parietal sinuses in a vombatid for the first time, an adaptation to increased skull size relative to the braincase. The presence of a prominent premaxillary spine may indicate that the species possessed a large, fleshy nose. Both features are convergent on other large‐bodied, non‐vombatid extinct megaherbivores of Australia such as Diprotodon optatum. We use the cranial remains to examine the phylogenetic relationships of giant wombats to other vombatids. Phylogenetic analysis using maximum parsimony and Bayesian inference indicates that Phascolomys, Ramsayia and Sedophascolomys form a clade, suggesting a single origin of gigantism within Vombatidae. This origin may be related to the exploitation of poor‐quality foods, and preceded extreme specializations observed in the cranial anatomy of the giant wombats. U‐series and combined U‐series and electron spin resonance (ESR) dating methods were applied to one fossil tooth. Age calculations systematically correlate the fossil remains to Marine Isotope Stage 5, and an age of c. 80 000 years can be proposed for this specimen. With only a single well‐dated occurrence for this taxon, it is currently impossible to determine when and why R. magna became extinct.
期刊介绍:
Papers in Palaeontology is the successor to Special Papers in Palaeontology and a journal of the Palaeontological Association (www.palass.org). The journal is devoted to the publication of papers that document the diversity of past life and its distribution in time and space.
Papers in Palaeontology is devoted to the publication of papers that document the diversity of past life and its distribution in time and space. As a sister publication to Palaeontology its focus is on descriptive research, including the descriptions of new taxa, systematic revisions of higher taxa, detailed biostratigraphical and biogeographical documentation, and descriptions of floras and faunas from specific localities or regions. Most contributions are expected to be less than 30 pp long but longer contributions will be considered if the material merits it, including single topic parts.
The journal publishes a wide variety of papers on palaeontological topics covering:
palaeozoology,
palaeobotany,
systematic studies,
palaeoecology,
micropalaeontology,
palaeobiogeography,
functional morphology,
stratigraphy,
taxonomy,
taphonomy,
palaeoenvironmental reconstruction,
palaeoclimate analysis,
biomineralization studies.