Geerinckx Tom, De Kegel Barbara
Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium.
J Anat. 2014 Aug;225(2):197-208. doi: 10.1111/joa.12196. Epub 2014 May 20.
Of those fishes scraping food off substrates and using head parts in substrate attachment for station-holding, the catfish families Loricariidae, Astroblepidae and Mochokidae display the most dramatically adapted morphologies. Loricariidae and Astroblepidae, living in the Neotropical freshwaters, exclusively contain suckermouth catfish species, and their anatomy and head kinematics have already been studied into detail. Among Mochokidae, living in the tropical freshwaters of Africa, only the chiloglanidine subfamily has a sucker mouth, and occupies similar niches in Africa as both Neotropical families do in South America. Having derived from relatively unrelated catfish ancestors, their anatomy is poorly known, and the nature of their scraping and station-holding capabilities is not known at all. This paper provides details on the chiloglanidine head anatomy and function (relating their anatomy to that of the non-suckermouth Mochokidae), and compares this Afrotropical suckermouth taxon with both Neotropical suckermouth families. It identifies both convergences and differing anatomical and kinematic solutions to the same key needs of food-scraping and station-holding suckermouth fishes. Chiloglanidine mochokids differ from both Neotropical families in having less mobile jaws, with an upper jaw assisting more in station-holding than in feeding. They share the highly mobile lower lip with both Neotropical taxa, although the configuration of the intermandibular/protractor hyoidei muscle system, changing the volume of the sucker-disc cavity, differs in all three taxa. Chiloglanidines have a single, posterior inflow opening into this cavity, whereas Loricariidae have two lateral openings, and Astroblepidae have none, using an opercular incurrent opening instead. The chiloglanidine buccal valve system consists of two passive valves, as in Astroblepidae. Although less diverse in number of genera and species, this Afrotropical suckermouth taxon possesses the anatomical and kinematic key elements allowing a successful occupation of a niche similar to the one found in the Loricariidae + Astroblepidae clade.
在那些从基质上刮取食物并利用头部在基质附着以保持位置的鱼类中，吸甲鲶科、石面鲶科和蝌蚪鲶科的鲶鱼展现出了最为显著的适应性形态。吸甲鲶科和石面鲶科生活在新热带地区的淡水中，只包含有吸盘口的鲶鱼物种，它们的解剖结构和头部运动学已经得到了详细研究。在生活于非洲热带淡水的蝌蚪鲶科中，只有奇洛拉鲶亚科有吸盘口，并且在非洲占据着与新热带地区这两个科在南美洲所占据的类似生态位。它们源自相对亲缘关系较远的鲶鱼祖先，其解剖结构鲜为人知，而且它们刮取食物和保持位置的能力的本质完全不为人知。本文详细介绍了奇洛拉鲶亚科的头部解剖结构和功能（将它们的解剖结构与非吸盘口的蝌蚪鲶科进行比较），并将这个非洲热带吸盘口分类群与新热带地区的两个吸盘口科进行比较。它识别出了在食物刮取和保持位置的吸盘口鱼类的相同关键需求方面的趋同以及不同的解剖和运动学解决方案。奇洛拉鲶亚科的蝌蚪鲶与新热带地区的两个科不同，它们的颌部活动较少，上颌在保持位置方面比在进食方面发挥的作用更大。它们与新热带地区的两个分类群都有高度可活动的下唇，尽管改变吸盘盘腔体积的下颌间/舌骨前肌系统的构造在这三个分类群中有所不同。奇洛拉鲶亚科有一个单一的、位于后方的进入这个腔的进水口，而吸甲鲶科有两个侧向开口，石面鲶科则没有，而是使用鳃盖进水口。奇洛拉鲶亚科的颊瓣系统由两个被动瓣膜组成，与石面鲶科一样。尽管在属和种的数量上多样性较低，但这个非洲热带吸盘口分类群拥有解剖和运动学的关键要素，使其能够成功占据与吸甲鲶科 + 石面鲶科分支中所发现的类似的生态位。
