The oldest Asian hesperornithiform from the Upper Cretaceous of Japan, and the phylogenetic reassessment of Hesperornithiformes
The oldest Asian hesperornithiform from the Upper Cretaceous of Japan, and the phylogenetic reassessment of Hesperornithiformes
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DOI：
10.1080/14772019.2017.1341960
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发表时间：
2018-06
影响因子：
2.6
通讯作者：
Tomonori Tanaka;Y. Kobayashi;K. Kurihara;A. Fiorillo;Manabu Kano
中科院分区：
文献类型：
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作者：
Tomonori Tanaka;Y. Kobayashi;K. Kurihara;A. Fiorillo;Manabu Kano
与北美更为丰富的记录相比，亚洲橙鸟目极为罕见。在亚洲，这些鸟类化石只能从蒙古的碎片材料中得知。在这里，我们描述了一种新的橙鸟形Chupkaornis keraorum gen的骨骼遗骸。等十一月产于日本北海道三笠市虾夷群的上白垩统鹿岛组（康尼亚阶至桑托阶）。这是亚洲保存最完好的橙鸟目材料，也是欧亚大陆东缘橙鸟目的首次报道。 Chupkaornis 具有独特的特征组合：股骨的手指状突出的胫腓骨嵴、深的、边缘化的侧向凹陷以及胸椎腹侧边缘的清晰边缘，以及胸椎的异体腔关节面。我们新的系统发育分析修正了 Hesperornithiformes 的系统发育关系。与之前的研究相比，Enaliornis 被指定为最基础的分类单元，Baptornis 被定位为比 Brodavis 更衍生。 Chupkaornis 是 Brodavis 分支和高等分类单元的姐妹分类单元。 Parahesperornis 和 Hesperornis 属于 Hesperornithidae（衍生的 Hesperornithiformes）。许多骨骼特征的变化集中在Hesperornithidae（Parahesperornis和更多衍生类群）的基部，并涉及骨盆带和后肢形态的改变（例如骨盆的背侧定向反转子、短而伸展的股骨，包括由第四趾第一个手指的专门远端关节面暗示的可能的叶趾足，以及主要坚固的第四趾指骨）。这些骨骼的改变可能是为了适应用脚推动的潜水行为。 http://zoobank.org/urn:lsid:zoobank.org:pub:FB783237-E565-4B74-9386-EADF8E12DFD4
Asian hesperornithiforms are extremely rare in contrast to the much more abundant record from North America. In Asia, these fossil birds are only known from fragmentary materials from Mongolia. Here we describe the skeletal remains of a new hesperornithiform Chupkaornis keraorum gen. et sp. nov. from the Upper Cretaceous Kashima Formation (Coniacian to Santonian) of the Yezo Group in Mikasa City, Hokkaido, Japan. This is the best-preserved hesperornithiform material from Asia and it is the first report of hesperornithiforms from the eastern margin of the Eurasian continent. Chupkaornis has a unique combination of characters: finger-like projected tibiofibular crest of femur, deep, emarginated lateral excavation with a sharply defined edge of the ventral margin of the thoracic vertebrae, and the heterocoelous articular surface of the thoracic vertebrae. Our new phylogenetic analysis revises the phylogenetic relationships of Hesperornithiformes. In contrast to previous studies, Enaliornis is assigned as the most basal taxon and Baptornis is positioned as more derived than Brodavis. Chupkaornis is a sister taxon to the clade of Brodavis and higher taxa. Parahesperornis and Hesperornis are positioned within Hesperornithidae, the derived Hesperornithiformes. Many of the skeletal character changes are concentrated at the base of Hesperornithidae (Parahesperornis and more derived taxa), and involve the modification of the pelvic girdle and hind limb morphology (e.g. dorsal directed antitrochanter of pelvis, short and sprawled femur, including probable lobe-toed feet suggested by the specialized distal articular surface of first digit of fourth toe, and predominantly robust digit IV phalanges). These skeletal modifications are likely adaptations for foot-propelled diving behaviour. http://zoobank.org/urn:lsid:zoobank.org:pub:FB783237-E565-4B74-9386-EADF8E12DFD4