古脊椎动物学报（中英文）2024，Vol.62Issue(1)：33-46,14.DOI:10.19615/j.cnki.2096-9899.230917
间型三棱齿象(Trilophodon connexus Hopwood,1935)属于豕棱齿象类而非嵌齿象
Reassessment of Trilophodon connexus Hopwood,1935 and attributing it to the Choerolophodontidae
摘要
Abstract
Trilophodon connexus Hopwood,1935 has long been considered a typical species of Gomphotherium in China.However,due to the unknown state of the mandibular symphysis and tusks,there is no definite evidence to assign"T.connexus"to Gomphotherium.Here we describe and reevaluate a hemimandible from the Halamagai Formation,Ulungur region,northern Junggar Basin,which was previously identified as Gomphotherium cf.G.shensiensis.The mandibular symphysis is deeply troughed and lacks mandibular tusks;therefore,it undoubtedly belongs to the Choerolophodontidae.Further comparison revealed that the cheek tooth morphology is identical to that of the type specimen of Trilophodon connexus.The characteristic features include high bunodonty,elongation of the m3 with four lophids,an only weakly chevroned lophid 2,enlargement of the posterior pretrite central conule 2,unfused state of the pretrite mesoconelet 2(if present)and anterior pretrite central conule 2,as well as the absence of ptychodonty,choerodonty,and cementodonty.Therefore,T.connexus Hopwood,1935 is a choerolophodontid rather than a species of Gomphotherium.Based on the above features,we provisionally refer to it as"Choerolophodon"connexus."Choerolophodon"connexus is characterized by the following features:weak or absent ptychodonty,choerodonty,and loph chevron(which were all strong in the typical species of Choerolophodon),as well as multiplication of the lophids in the m3,which were similar to that of the North American Gnathabelodon.Therefore,Gnathabelodon might represent a distinct lineage within the Choerolophodontidae,and may be derived from the East Asian"Choerolophodon"connexus.关键词
中新世/嵌齿象/颌门齿象/豕棱齿象/长鼻类Key words
Miocene/Gomphotherium/Gnathabelodon/Choerolophodon/proboscidean分类
生物科学引用本文复制引用
李春晓,陈津,王世骐..间型三棱齿象(Trilophodon connexus Hopwood,1935)属于豕棱齿象类而非嵌齿象[J].古脊椎动物学报（中英文）,2024,62(1):33-46,14.基金项目
第二次青藏高原综合科学考察研究项目(编号:2019QZKK0705)资助.We thank Laura E.WILSON,the curator of FHSU,who kindly allowed us access to the type specimen of Gnathabelodon thorpei and allowed us to publish new images of it.We thank Ye Jie of the IVPP,China,for his extensive advice on this work.This work was supported by the Second Tibetan Plateau Scientific Expedition(2019QZKK0705). （编号:2019QZKK0705）
