Schaefer S A, Aquino A E
Division of Vertebrate Zoology, American Museum of Natural History, New York, New York 10024-5192, USA.
J Morphol. 2000 Dec;246(3):212-27. doi: 10.1002/1097-4687(200012)246:3<212::AID-JMOR5>3.0.CO;2-S.
Morphology of the postotic laterosensory canal was surveyed across loricarioid and outgroup catfishes in order to resolve conflicting statements regarding homology and phylogenetic significance of intrinsic character variation. A pterotic branch is widespread among catfishes and has been identified as a synapomorphy for siluriforms, but its presence in loricarioid catfishes has been disputed. In contrast to previous statements that absence of a pterotic branch is synapomorphic for loricarioids, we confirm the presence of a pterotic branch in Nematogenys inermis and other trichomycterids, callichthyids, and loricariids. The pterotic branch is secondarily absent in scoloplacids and astroblepids. We present criteria for establishing homology of the pterotic branch and review character state optimization schemes on the currently accepted phylogeny. The postotic region of loricariids is further specialized in having an expanded swimbladder capsule that incorporates the trunk lateral line canal and has a lateral opening covered by a greatly expanded pterotic complex. The trunk lateral line enters the swimbladder capsule mesial to the pterotic lateral wall and passes anteromedially as a fleshy tube before forming the postotic canal in the pterotic, a morphology reported previously for a single loricariid representative. Variation in the relative extent and topographic position of postotic canal branches and other morphologies is diagnostic of certain loricariid taxa, suggesting a rich character complex of potential utility in phylogeny reconstruction.
为了解决关于内耳后外侧感觉管同源性及内在特征变异的系统发育意义的相互矛盾的说法，我们对内耳后外侧感觉管的形态进行了研究，涉及吸甲鲶科鱼类及其外类群鲶鱼。翼耳骨分支在鲶鱼中广泛存在，并被确定为鲶形目的一个共衍征，但它在吸甲鲶科鱼类中的存在一直存在争议。与之前认为无翼耳骨分支是吸甲鲶科鱼类共衍征的说法相反，我们证实了无鳞吸甲鲶及其他毛鼻鲶科、美鲶科和甲鲶科鱼类中存在翼耳骨分支。在长背鲶科和星项鲶科中，翼耳骨分支是次生缺失的。我们提出了确定翼耳骨分支同源性的标准，并回顾了在当前公认的系统发育树上的特征状态优化方案。甲鲶科鱼类的内耳后区域进一步特化，具有一个扩大的鳔囊，该鳔囊包含躯干侧线管道，并具有一个被大大扩展的翼耳骨复合体覆盖的外侧开口。躯干侧线在翼耳骨外侧壁的内侧进入鳔囊，并作为一条肉质管向前内侧延伸，然后在翼耳骨中形成内耳后管道，这种形态先前已在一种甲鲶科鱼类代表中报道过。内耳后管道分支的相对范围和地形位置的变化以及其他形态特征可用于诊断某些甲鲶科分类单元，这表明在系统发育重建中可能具有潜在用途的丰富特征复合体。
