Scales and dermal skeletal histology of an early bony fish Psarolepis romeri and their bearing on the evolution of rhombic scales and hard tissues.

Recent discoveries of early bony fishes from the Silurian and earliest Devonian of South China (e.g. Psarolepis, Achoania, Meemannia, Styloichthys and Guiyu) have been crucial in understanding the origin and early diversification of the osteichthyans (bony fishes and tetrapods). All these early fish...

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Main Authors: Qingming Qu, Min Zhu, Wei Wang
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3621673?pdf=render
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author Qingming Qu
Min Zhu
Wei Wang
author_facet Qingming Qu
Min Zhu
Wei Wang
author_sort Qingming Qu
collection DOAJ
description Recent discoveries of early bony fishes from the Silurian and earliest Devonian of South China (e.g. Psarolepis, Achoania, Meemannia, Styloichthys and Guiyu) have been crucial in understanding the origin and early diversification of the osteichthyans (bony fishes and tetrapods). All these early fishes, except Guiyu, have their dermal skeletal surface punctured by relatively large pore openings. However, among these early fishes little is known about scale morphology and dermal skeletal histology. Here we report new data about the scales and dermal skeletal histology of Psarolepis romeri, a taxon with important implications for studying the phylogeny of early gnathostomes and early osteichthyans. Seven subtypes of rhombic scales with similar histological composition and surface sculpture are referred to Psarolepis romeri. They are generally thick and show a faint antero-dorsal process and a broad peg-and-socket structure. In contrast to previously reported rhombic scales of osteichthyans, these scales bear a neck between crown and base as in acanthodian scales. Histologically, the crown is composed of several generations of odontodes and an irregular canal system connecting cylindrical pore cavities. Younger odontodes are deposited on older ones both superpositionally and areally. The bony tissues forming the keel of the scale are shown to be lamellar bone with plywood-like structure, whereas the other parts of the base are composed of pseudo-lamellar bone with parallel collagen fibers. The unique tissue combination in the keel (i.e., extrinsic Sharpey's fibers orthogonal to the intrinsic orthogonal sets of collagen fibers) has rarely been reported in the keel of other rhombic scales. The new data provide insights into the early evolution of rhombic (ganoid and cosmoid) scales in osteichthyans, and add to our knowledge of hard tissues of early vertebrates.
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spelling doaj.art-1f25f91a2aa249549d8f2fcf3679fcb32022-12-21T19:15:14ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0184e6148510.1371/journal.pone.0061485Scales and dermal skeletal histology of an early bony fish Psarolepis romeri and their bearing on the evolution of rhombic scales and hard tissues.Qingming QuMin ZhuWei WangRecent discoveries of early bony fishes from the Silurian and earliest Devonian of South China (e.g. Psarolepis, Achoania, Meemannia, Styloichthys and Guiyu) have been crucial in understanding the origin and early diversification of the osteichthyans (bony fishes and tetrapods). All these early fishes, except Guiyu, have their dermal skeletal surface punctured by relatively large pore openings. However, among these early fishes little is known about scale morphology and dermal skeletal histology. Here we report new data about the scales and dermal skeletal histology of Psarolepis romeri, a taxon with important implications for studying the phylogeny of early gnathostomes and early osteichthyans. Seven subtypes of rhombic scales with similar histological composition and surface sculpture are referred to Psarolepis romeri. They are generally thick and show a faint antero-dorsal process and a broad peg-and-socket structure. In contrast to previously reported rhombic scales of osteichthyans, these scales bear a neck between crown and base as in acanthodian scales. Histologically, the crown is composed of several generations of odontodes and an irregular canal system connecting cylindrical pore cavities. Younger odontodes are deposited on older ones both superpositionally and areally. The bony tissues forming the keel of the scale are shown to be lamellar bone with plywood-like structure, whereas the other parts of the base are composed of pseudo-lamellar bone with parallel collagen fibers. The unique tissue combination in the keel (i.e., extrinsic Sharpey's fibers orthogonal to the intrinsic orthogonal sets of collagen fibers) has rarely been reported in the keel of other rhombic scales. The new data provide insights into the early evolution of rhombic (ganoid and cosmoid) scales in osteichthyans, and add to our knowledge of hard tissues of early vertebrates.http://europepmc.org/articles/PMC3621673?pdf=render
spellingShingle Qingming Qu
Min Zhu
Wei Wang
Scales and dermal skeletal histology of an early bony fish Psarolepis romeri and their bearing on the evolution of rhombic scales and hard tissues.
PLoS ONE
title Scales and dermal skeletal histology of an early bony fish Psarolepis romeri and their bearing on the evolution of rhombic scales and hard tissues.
title_full Scales and dermal skeletal histology of an early bony fish Psarolepis romeri and their bearing on the evolution of rhombic scales and hard tissues.
title_fullStr Scales and dermal skeletal histology of an early bony fish Psarolepis romeri and their bearing on the evolution of rhombic scales and hard tissues.
title_full_unstemmed Scales and dermal skeletal histology of an early bony fish Psarolepis romeri and their bearing on the evolution of rhombic scales and hard tissues.
title_short Scales and dermal skeletal histology of an early bony fish Psarolepis romeri and their bearing on the evolution of rhombic scales and hard tissues.
title_sort scales and dermal skeletal histology of an early bony fish psarolepis romeri and their bearing on the evolution of rhombic scales and hard tissues
url http://europepmc.org/articles/PMC3621673?pdf=render
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