文章基本信息

标题：On the largest Ichthyosaurus: A new specimen of Ichthyosaurus somersetensis containing an embryo
本地全文：下载
作者：DEAN R. LOMAX ; SVEN SACHS ; SVEN SACHS 等
期刊名称：Acta Palaeontologica Polonica
印刷版ISSN：0567-7920
电子版ISSN：1732-2421
出版年度：2017
卷号：62
期号：3
页码：575-584
DOI：10.4202/app.00376.2017
语种：English
出版社：Institute of Paleobiology PAS
摘要：A formerly undescribed Ichthyosaurus specimen from the collection of the Niedersächsisches Landesmuseum (Lower Saxony State Museum) in Hannover, Germany, provides valuable new information. The skeleton was collected from the Lower Jurassic strata (lower Hettangian, Blue Lias Formation) of Doniford Bay, Somerset, UK. However, the specimen is a composite as almost the entire tail has been added and other parts are reconstructed. Regardless of the incomplete preservation, the estimated total length of this individual, based on the skull and precaudal length, is between 300 and 330 cm and it is thus the largest unequivocal example of the genus Ichthyosaurus. Cranial and postcranial characters, specifically from the maxilla, lacrimal, jugal, the humerus, and the ilium justify a referral to I. somersetensis. A fork-like shape of the proximal end of the ilium is unusual and has not been reported for any species of Ichthyosaurus. Likewise the presence of four elements in the third row of the hindfin, indicated by the presence of a bifurcation is novel for the species and has wider implications for the taxonomic utility of hindfins within the genus. The specimen also bears an embryo, which is only the third embryo known for Ichthyosaurus and the first to be positively identified to species level.
关键词：Ichthyosauria;Ichthyosaurus somersetensis;embryo;Jurassic;Hettangian;UK;Somerset