MICROSAURS AND THE ORIGIN OF CAPTORHINOMORPH REPTILES
MICROSAURS AND THE ORIGIN OF CAPTORHINOMORPH REPTILES
复制标题
微型恐龙和 Captorhinomorph 爬行动物的起源
DOI：
10.1093/icb/5.2.277
复制
发表时间：
1965
影响因子：
2.6
通讯作者：
J. T. Gregory
中科院分区：
文献类型：
--
作者：
J. T. Gregory
微龙是古生代的鳞椎两栖类，身体细长，四肢无力。他们坚固的头骨没有耳凹，有大的颞上骨，广泛地将鳞骨和顶骨分开，还有双枕骨髁。镫骨由一个大的踏板和极短的鼻小柱组成。椎骨缺乏椎体间。最初基于一种爬行动物，Hylonomus lyelli，由道森在1863年，该命令Microsauria长期以来一直局限于这些小型两栖动物（罗默，1950）。由于头骨和椎骨表面上的相似性，原始的captorhinomorph爬行动物和微型龙之间的混淆不断。这种混淆和在石炭纪早期沉积物中偶尔出现的类似微型龙的椎骨导致了微型龙是爬行动物祖先的建议（参见。Vaughn，1962）。
尾鼻形类与微龙类的不同之处在于它们的小颞骨、单一的枕骨髁、镫骨，镫骨上有长的骨柱，在方骨上有一个小坑，并有一个背突，以及背侧的中间骨。正如沃恩（Vaughn，1960）所指出的，Captorhinomorph的祖先很可能不是剑齿龙，但他们也不可能具有微龙的特化特征。它们的来源必须在更接近横鳍鱼类的形式中寻找。
微型龙的双枕关节和耳区与有尾目和裸泳目相似。它们与Lissamphibia的不同之处在于牙齿中没有非钙化区。目前，没有任何标准可以明确指出哪些结构是趋同发展的。微龙类可能与现代蝾螈和螈的祖先有关，但没有证据表明。
Microsaurs are Paleozoic lepospondylous Amphibia with slender bodies and weak limbs. Their solidly roofed skulls lack otic notches, have large supratemporals widely separating the squamosal from parietal, and double occipital condyles. The stapes consists of a large footplate and extremely short columella. Vertebrae lack intercentra. Originally based on a reptile, Hylonomus lyelli , by Dawson in 1863, the Order Microsauria has long been restricted to these small amphibians (Romer, 1950). Repeated confusion between primitive captorhinomorph reptiles and microsaurs steins from superficial similarities between both skulls and vertebrae. This confusion and occasional microsaur-like vertebrae in early Carboniferous deposits have led to suggestions that microsaurs are reptilian ancestors (cf. Vaughn, 1962).
Captorhinomorphs differ from microsaurs in their small supratemporal bone, single occipital condyle, stapes with long columella reaching a pit in the quadrate and bearing a dorsal process, and dorsal intercentra. Captorhinomorph ancestors were probably not labyrinthodonts, as Vaughn (1960) has pointed out, but they could not have had the characteristic specializations of microsaurs. Their source must be sought in forms much closer to crossopterygian fish.
Microsaurs resemble both urodeles and gymnophionans in their double occipital joint and otic region. They differ from Lissamphibia in the absence of a non-calcified zone in the teeth. At present, no criteria indicate decisively which structures developed convergently. Microsaurs are possibly but not demonstrably related to the ancestry of modern salamanders and caecilians.