REDESCRIPTION OF THE OLDEST CROWN CLADE PENGUIN: CRANIAL OSTEOLOGY, JAW MYOLOGY, NEUROANATOMY, AND PHYLOGENETIC AFFINITIES OF MADRYNORNIS MIRANDUS
REDESCRIPTION OF THE OLDEST CROWN CLADE PENGUIN: CRANIAL OSTEOLOGY, JAW MYOLOGY, NEUROANATOMY, AND PHYLOGENETIC AFFINITIES OF MADRYNORNIS MIRANDUS
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DOI：
10.1080/02724634.2018.1445636
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发表时间：
2018-01-01
影响因子：
1.4
通讯作者：
Tambussi, Claudia P.
中科院分区：
文献类型：
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作者：
Degrange, Federico J.;Ksepka, Daniel T.;Tambussi, Claudia P.
马德里诺尼斯·米兰德斯是从几乎完整的关节骨骼中发现的为数不多的企鹅化石之一，它代表了理解企鹅茎-冠转变的关键分类群。尽管在正型标本中保存了丰富的形态特征数据，但这一早、晚中新世分类群的系统发育位置仍然存在争议。对马德里诺尼斯·米兰德斯正型的重新检查为企鹅冠林地内的安置提供了支持。然而，这种放置对分子信号高度敏感，当分子数据被排除时，Madrynorris正好落在树冠空地之外。马德里诺尼斯的神经解剖学与现存的企鹅有许多共同的派生特征，包括无脑脑形状，极少的球状嗅觉，以及缺乏耳间通路。然而，脑内铸型与所有现存物种的不同之处在于，矢状隆起(Wulst)的尾部膨大较少，视盖相对较不发达，小叶较结实且更偏向。马德里诺尼斯人的颅骨和重建的颌肌学表明，他们的饮食主要是以鱼为主，这很可能是将马德利诺尼斯人、因古萨人、尤德普图拉人和斯菲尼库斯人结合在一起的格来德人的特征。
Madrynornis mirandus, one of the few fossil penguins known from a nearly complete articulated skeleton, represents a key taxon for understanding the stem-crown transition in penguins. Despite the wealth of morphological character data preserved in the holotype specimen, the phylogenetic placement of this early late Miocene taxon has remained controversial. Reexamination of the Madrynornis mirandus holotype provides support for placement within the penguin crown Glade. However, this placement is highly sensitive to the molecular signal and Madrynornis falls just outside the crown Glade when molecular data are excluded. The neuroanatomy of Madrynornis shares many derived features with extant penguins, including an airencephalic brain shape, highly reduced bulbul olfactorius, and absence of an interaural pathway. However, the brain endocast differs from all surveyed extant species in that the eminentia sagittalis (wulst) is less caudally expanded, the tectum opticus is relatively less developed, and the flocculus is stouter and more laterally disposed. The cranial osteology and reconstructed jaw myology of Madrynornis suggest a primarily piscivorous diet, which likely characterizes the Glade uniting Madrynornis, Inguza, Eudyptula, and Spheniscus.