Meeting Abstract

36.5  Jan. 5  Non-algae scraping vs algae scraping, comparison between Synodontis and Atopochilus (Siluriformes: Mochokidae) IDE, C.*; DE PUYSSELEIR, J.; HUYSENTRUYT, F.; GEERINCKX, T.; ADRIAENS, D.; Ghent University celine.ide@ugent.be

Until recently specializations related to algae-scraping have been studied in cichlids and loricariid catfishes, but very little has been done on the algae-scraping species of the African mochokid catfishes. In this study we examined the head morphology (osteology and myology) of both a non-algae scraper (Synodontis schall en S. ocellifer) and an algae scraper with a suckermouth (Atopochilus savorgnani). Synodontis is the largest genus of the family Mochokidae. We compared the morphological features of Synodontis with those of Atopochilus savorgnani, in order to gain some insight on possible relationships between musculoskeletal specializations and algae-scraping. The osteological research was done by means of cleared and stained specimens, for the myological study dissections were performed. It could be concluded that Synodontis shows the general head morphology of Siluriformes, and thus can be considered to represent the plesiomorphic condition in mochokids. After comparison we were able to relate some differences between the two taxa to algae scraping in A. savorgnani. In the latter, the dentary is rotated about 180� and is bigger, providing ample space for the ventrally pointed teeth, an adaptation to algae scraping also seen in loricariids. A. savorgnani also has smaller eyes and shorter barbels. Given their benthic feeding behaviour these fishes probably rely more on the sensory lip surface than on large eyes and long barbels. In contrast, Synodontis feeds in the water column, where light conditions are better and barbels are more efficient for probing the surrounding water during swimming.