A primitive fish provides key characters bearing on deep osteichthyan phylogeny

作者：Zhu M^*; Yu XB; Wang W; Zhao WJ; Jia LT

来源：Nature, 2006, 441(7089): 77-80.

DOI：10.1038/nature04563

Osteichthyans, or bony vertebrates, include actinopterygians (teleosts and their relatives) and sarcopterygians (coelacanths, lungfishes and tetrapods). Despite features found in basal actinopterygians (for example, Dialipina and Ligulalepis)(1-3) and basal sarcopterygians (for example, Psarolepis and Achoania)(4,5), the morphological gap between the two lineages remains wide and how sarcopterygians developed a dermal surface covering known as cosmine (composed of a pore-canal network and a single layer of odontodes and enamel) is still poorly known(6-10). Here we describe a primitive fossil fish, Meemannia eos gen. et sp. nov., that possesses an actinopterygian-like skull roof and a cosmine-like dermal surface combining a pore-canal network (found in various fossil sarcopterygians) with superimposed layers of odontodes and enamel (previously known in actinopterygians and some acanthodians(11-13)). This 405-million-year-old fish from the Lower Devonian of Yunnan (China) demonstrates that cosmine in many fossil sarcopterygians arose step by step through the acquisition of a pore-canal network followed by the subsequently developed ability to resorb previous generations of odontodes and enamel. Meemannia provides key characters for studying deep osteichthyan phylogeny and indicates a possible morphotype for the common ancestor of actinopterygians and sarcopterygians.

• 出版日期2006-5-4
• 单位中国科学院古脊椎动物与古人类研究所