PAIRED FIN SKELETONS AND RELATIONSHIPS OF THE FOSSIL GROUP POROLEPIFORMES (OSTEICHTHYES, SARCOPTERYGII)
PAIRED FIN SKELETONS AND RELATIONSHIPS OF THE FOSSIL GROUP POROLEPIFORMES (OSTEICHTHYES, SARCOPTERYGII)
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DOI：
10.1111/j.1096-3642.1989.tb01824.x
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发表时间：
1989-06-01
影响因子：
2.8
通讯作者：
AHLBERG, PE
中科院分区：
文献类型：
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作者：
AHLBERG, PE
描述了孔状鱼类LGlyptolepis(骨鱼目：肉鳍目：孔形目)的内骨骼环、异肢和成对鳍支撑物。胸鳍骨骼仅见于近端，骨盆鳍骨是残缺不全的，但肩峰突、无脊椎和骨盆带可完整重建。无针线虫完全是皮下的。胸鳍骨骼呈双列结构，有大量的轴向中球，而腹鳍含有较少的中球，且具有很强的不对称性，仅有极少数的后径向。肩喙突本质上类似于Jarvik(1980)的重建，但有一个更细长的肩臼；这具有功能意义。骨盆带与真翅目昆虫一样，由两个分开的部分组成，但与该属不同的是缺乏背外侧支。本文对其他孔雀形属的成对鳍结构的证据进行了简要的调查，以确定在龟形目中所见的这些结构是否可能是孔雀形目的代表性。对鳍骨骼的形态和肌肉附着性的研究表明，鳍的运动模式与新角形目的显著不同。为了建立进化的两极，将石龙鱼的鳍支撑物和鳍带与其他石棺蕨类以及放线鸟、安慰剂和鲨鱼的鳍支撑物和鳍带进行比较。字形显示了一些派生的字符。比较所得的信息被用来构建最大简约分支图，腔棘鱼作为孔尾鱼+肺鱼的姊妹群，根齿+四足动物和骨甲鱼作为该支系的连续姊妹群。根据该分支图，考虑了极性不确定的特征。与最近发表的分支图的比较表明，没有一个与这项研究的结果完全一致。
The endoskeletal girdles, anocleithrum and paired fin supports of the porolepiform fish LGlyptolepis (Osteichthyes:Sarcopterygii: Porolepiformes) are figured and described. The pectoral fin skeleton is known from the proximal part only and the pelvic fin skeleton is fragmentary, but the scapulocoracoid, anocleithrum and pelvic girdle can be reconstructed in their entirety. The anocleithrum is entirely subdermal. The pectoral fin skeleton is shown to be biserial, with a large number of axial mesomeres, whereas the pelvic fin contains fewer mesomeres and is strongly asymmetrical with very few postaxial radials. The scapulocoracoid is essentially similar to a reconstruction figured by Jarvik (1980), but has a more elongate glenoid; this has functional implications. The pelvic girdle consists of two separate halves as in Eusthenopteron, but differs from that genus in lacking dorsolateral rami. A brief survey of the evidence of paired fin structure in other porolepiform genera is carried out to establish whether the structures seen in Glyptolepis are likely to be representative for the Porolepiformes. A study of the morphology and muscle attachments of the paired fin skeletons indicates that the pattern of fin movement was significantly different from that in Neoceratodus. The fin suppors and girdles of Glyptolepis are compared with those of other sarcopterygian groups as well as with actinopterygians, placoderms and sharks, in order to establish evolutionary polarities. Glyptolepis is shown to display a number of derived characters. The information gained from the comparison is used to construct a maximum parsimony cladogram, which places coelacanths as the sister group of porolepiforms + lungfishes, with the rhizodonts + tetrapods and osteolepiforms as successive sister groups of this clade. Characters of uncertain polarity are considered in the light of this cladogram. A comparison with recently published cladograms shows that none are completely compatible with the results from this study.