A new osteichthyan from the late Silurian of Yunnan, China
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Date
2017-03-08
Authors
Choo, Brian
Zhu, Min
Qu, Qingming
Yu, Xiaobo
Jia, Liantao
Zhao, Wenjin
Journal Title
Journal ISSN
Volume Title
Publisher
Public Library of Science
Rights
Copyright: © 2017 Choo et al.
Rights Holder
The authors
Abstract
Our understanding of early gnathostome evolution has been hampered by a generally scant fossil record beyond the Devonian. Recent discoveries from the late Silurian Xiaoxiang Fauna of Yunnan, China, have yielded significant new information, including the earliest articulated osteichthyan fossils from the Ludlow-aged Kuanti Formation. Here we describe the partial postcranium of a new primitive bony fish from the Kuanti Formation that represents the second known taxon of pre-Devonian osteichthyan revealing articulated remains. The new form, Sparalepis tingi gen. et sp. nov., displays similarities with Guiyu and Psarolepis, including a spine-bearing pectoral girdle and a placoderm-like dermal pelvic girdle, a structure only recently identified in early osteichthyans. The squamation with particularly thick rhombic scales shares an overall morphological similarity to that of Psarolepis. However, the anterior flank scales of Sparalepis possess an unusual interlocking system of ventral bulges embraced by dorsal concavities on the outer surfaces. A phylogenetic analysis resolves Sparalepis within a previously recovered cluster of stem-sarcopterygians including Guiyu, Psarolepis and Achoania. The high diversity of osteichthyans from the Ludlow of Yunnan strongly contrasts with other Silurian vertebrate assemblages, suggesting that the South China block may have been an early center of diversification for early gnathostomes, well before the advent of the Devonian “Age of Fishes”.
Description
Copyright: © 2017 Choo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and
reproduction in any medium, provided the original author and source are credited.
Keywords
gnathostome evolution, fossils, Devonian., Silurian Xiaoxiang Fauna of Yunnan, China, osteichthyan fossils, Ludlow-aged Kuanti Formation, primitive bony fish
Citation
Choo B, Zhu M, Qu Q, Yu X, Jia L, Zhao W (2017) A new osteichthyan from the late Silurian of Yunnan, China. PLoS ONE 12(3): e0170929. doi:10.1371/journal.pone.0170929