Taxonomic revision of Anthracokeryx thailandicus Ducrocq, 1999 (Anthracotheriidae, Microbunodontinae) from the Upper Eocene of Thailand

doi:10.19615/j.cnki.1000-3118.200618

Abstract

Abstract:

The anthracotheriid (Mammalia, Cetartiodactyla) species Anthracokeryx thailandicus from the Upper Eocene of Thailand is redescribed in details and a revision of its phylogenetic position within the family is proposed. A combination of important dental differences has been observed that led to attribute the Thai form to a distinct genus, Geniokeryx gen. nov., which represents the third genus included into the Microbunodontinae. The new genus is characterized mainly by its unfused short and deep mandibular symphysis, massive lower and upper premolars, weakly selenodont upper molars that exhibit a protostyle and lack an ectometacristule. The peculiar morphology of its symphysis might have been a sexually dimorphic feature that provided the role of a lateral protection for the enlarged upper canine in males as seen in some Paleogene nimravid carnivorans like Eusmilus. A short review of some Anthracokeryx species from China suggests that A. dawsoni might be synonymous to A. sinensis.

Key words: Thailand, Late Eocene, Anthracotheriidae, Microbunodontinae, Anthracokeryx, Geniokeryx

摘要：

重新描述了泰国晚始新世石炭兽类(哺乳动物纲,鲸偶蹄类)的泰国先炭兽(Anthracokeryx thailandicus), 修订了该种在科内的系统发育位置。据观察,泰国标本具有一系列重要的牙齿差异,因而建立一新属颏炭兽(Geniokeryx gen. nov.), 代表了归入小丘齿兽亚科(Microbunodontinae)的第3个属。新属的主要特征是下颌联合短而深,未愈合;上、下前臼齿粗壮;上臼齿呈微弱新月型,具原附尖,无后小尖外棱。下颌联合的独特形态可能属于性双型特征,为雄性增大的上犬齿提供了侧面保护,就像某些古近纪祖猎虎类食肉动物,例如Eusmilus一样。简要评述了中国发现的先炭兽属的一些种,认为A. dawsoni可能是A. sinensis的同物异名。

关键词: 泰国, 晚始新世, 石炭兽科, 小丘齿兽亚科, 先炭兽, 颏炭兽

CLC Number:

Q915.873

DUCROCQ Stéphane. Taxonomic revision of Anthracokeryx thailandicus Ducrocq, 1999 (Anthracotheriidae, Microbunodontinae) from the Upper Eocene of Thailand. Vertebrata Palasiatica, 2020, 58(4): 293-304.

DUCROCQ Stéphane. 2020, 58(4): 293-304, 泰国晚始新世Anthracokeryx thailandicus Ducrocq, 1999(石炭兽科,小丘齿兽亚科)的分类修订. 古脊椎动物学报.

Figures/Tables 3

References 17

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