Didier Dominique A, LeClair Elizabeth E, Vanbuskirk Dana R
Academy of Natural Sciences, Philadelphia, Pennsylvania.
Thomas Jefferson University, Philadelphia, Pennsylvania.
J Morphol. 1998 Apr;236(1):25-47. doi: 10.1002/(SICI)1097-4687(199804)236:1<25::AID-JMOR2>3.0.CO;2-N.
The development of Callorhinchus milii, a primitive chondrichthyan fish (Subclass Holocephali) is described in detail based on a complete series of embryos from stage 17 to hatching. The external features of these specimens, in comparison with other chondrichthyan embryos, are used to establish the first staging table for any chimaeroid species. Each stage of C. milii is defined by a suite of morphological characters in addition to total length, including the number of somites, extent of external pigmentation, eye size and shape, head flexure, heart morphology, and size and shape of paired and unpaired fins. Particular attention is given to features of the gill arches and associated structures, including external gill filaments and the opercular flap. Embryos of this species also possess a transient rostral bulb, a feature unique to chimaeroids. Embryological development of Callorhinchus milii is similar to that previously described for sharks and batoids (Subclass Elasmobranchii), including the spiny dogfish, Squalus acanthias, the Japanese bullshark, Heterodontus japonicus, the lesser spotted dogfish, Scyliorhinus canicula, the frill shark, Chlamydoselachus anguineus, the guitarfish, Rhinobatus halavi, and the skate, Raja brachyura. Callorhinchus milii is also similar in overall development to another holocephalan, Hydrolagus colliei. A review of previous staging schemes confirms that early morphological development in all three major chondrichthyan lineages (sharks, batoids, and chimaeras) can be correlated using a common set of stages. A uniform staging system is provided that should prove useful in continuing ontogenetic and phylogenetic studies of this entire clade of fishes. J. Morphol. 236:25-47, 1998. © 1998 Wiley-Liss, Inc.
基于一系列从第17阶段到孵化阶段的完整胚胎，详细描述了原始软骨鱼类（全头亚纲）澳洲银鲛的发育过程。将这些标本的外部特征与其他软骨鱼类胚胎相比较，以此为任何银鲛类物种建立了首个分期表。除了全长外，澳洲银鲛的每个阶段都由一系列形态特征定义，包括体节数量、外部色素沉着范围、眼睛大小和形状、头部弯曲度、心脏形态以及成对和不成对鳍的大小和形状。特别关注鳃弓及相关结构的特征，包括外部鳃丝和鳃盖瓣。该物种的胚胎还具有一个短暂的吻球，这是银鲛类独有的特征。澳洲银鲛的胚胎发育与先前描述的鲨鱼和鳐类（板鳃亚纲）相似，包括棘鲨、日本公牛鲨、窄头双髻鲨、皱鳃鲨、斑纹犁头鳐和短吻鳐。澳洲银鲛在整体发育上也与另一种全头类动物银鲛相似。对先前分期方案的回顾证实，所有三个主要软骨鱼类谱系（鲨鱼、鳐类和银鲛）的早期形态发育可以使用一组通用阶段进行关联。提供了一个统一的分期系统，这在对整个鱼类进化枝的个体发育和系统发育研究中应该会很有用。《形态学杂志》236:25 - 47，1998年。© 1998威利 - 利斯公司。
