Fernández Luis, Schaefer Scott A
Division of Vertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA.
Mol Phylogenet Evol. 2009 Aug;52(2):416-23. doi: 10.1016/j.ympev.2009.02.016. Epub 2009 Feb 28.
Phylogenetic relationships among the trichomycterid catfishes are investigated for the first time using molecular sequence data. Data derived from mitochondrial and nuclear DNA sequences for representatives of 17 genera were analyzed to test previous hypotheses of relationships among trichomycterid subfamilies, the monophyly of the subfamily Stegophilinae, and the monophyly and relationships among the genera of parasitic members of the family. We analyzed 2325 aligned base-pairs from mitochondrial 12S, 16S, ND4 (tRNA(His) tRNA(Ser)), and the nuclear histone H3 gene for representatives of 10 of 12 stegophiline and 3 of 4 vandelliine genera, plus 10 outgroup taxa selected to represent the range of subfamilial diversity. Maximum parsimony and likelihood approaches resolved a monophyletic semiparasitic Stegophilinae as the sister-group of the obligate hematophagous Vandelliinae. At the level of subfamilies, the pattern of relationships of the parasitic members among the remainder of the family is fully congruent with the most recent hypothesis of relationships for trichomycterids based exclusively on morphological data. Within stegophilines, our results differ from multiple previous morphological studies in recovery of (1) Haemomaster and Ochmacanthus as sister-taxa, (2) the morphologically plesiomorphic Pareidon microps nested within a relatively distal part of the tree topology, (3) Apomatoceros as sister to Henonemus, rather than to the morphologically similar Megalocentor. These result indicate that parasitism arose once and was unreversed within the Trichomycteridae. Survey of diet and feeding morphology among trichomycterids suggests that the semiparasitic lifestyle of the members of the Stegophilinae was retained in the enigmatic Pareiodon microps, despite reversal to the generalized trichomycterid condition of the associated morphological specializations found in all other stegophilines. These results further support the reconstruction of semiparasitism, rather than blood feeding, for the shared common ancestor of the parasitic Trichomycteridae.
首次利用分子序列数据研究了毛鼻鲶科鲶鱼之间的系统发育关系。分析了来自17个属代表的线粒体和核DNA序列数据，以检验先前关于毛鼻鲶亚科之间关系的假设、Stegophilinae亚科的单系性以及该科寄生成员属之间的单系性和关系。我们分析了来自线粒体12S、16S、ND4（tRNA(His) tRNA(Ser)）以及核组蛋白H3基因的2325个比对碱基对，这些数据来自12个Stegophilinae属中的10个属以及4个Vandelliinae属中的3个属的代表，另外还选取了10个外类群分类单元以代表亚科多样性的范围。最大简约法和似然法分析结果表明，单系的半寄生性Stegophilinae亚科是专性吸血的Vandelliinae亚科的姐妹群。在亚科层面，该科其余成员中寄生成员的关系模式与仅基于形态学数据得出的毛鼻鲶科关系的最新假设完全一致。在Stegophilinae亚科内部，我们的结果与之前多项形态学研究不同，表现为：（1）Haemomaster属和Ochmacanthus属为姐妹分类单元；（2）形态学上的近祖型Pareidon microps嵌套在树形拓扑结构相对较远的部分；（3）Apomatoceros属是Henonemus属的姐妹属，而不是与形态学上相似的Megalocentor属为姐妹属。这些结果表明，寄生现象在毛鼻鲶科中仅出现过一次且未发生逆转。对毛鼻鲶科鱼类的食性和摄食形态的调查表明，尽管Pareiodon microps在相关形态特化方面已逆转至所有其他Stegophilinae亚科成员普遍具有的毛鼻鲶科鱼类状态，但Stegophilinae亚科成员的半寄生生活方式仍得以保留。这些结果进一步支持了寄生性毛鼻鲶科鱼类共同祖先具有半寄生习性而非吸血习性的推断。
