Meeting Abstract

P2.72  Jan. 5  How do you scrape? Diversity and development of teeth and horny lip projections among the Loricariidae GEERINCKX, T.*; DE POORTER, J.; MAES, D.; NIJS, K.; ADRIAENS, D.; Ghent University tom.geerinckx@ugent.be

The neotropical suckermouth armored catfishes use their sucker-like mouth to adhere to submerged substrates. They have drastically modified jaws that point their teeth ventrally, towards the substrate. It is a well known fact that the many loricariid species differ in habitat, feeding habits, and preferred type of food. These facts are examined from an ecomorphological point of view. Not only the jaws and the associated musculature vary between species, but also the scraping devices themselves: both teeth and unicellular horny lip projections (unculi). The loricariid teeth are among the most remarkable of all fishes, being Z-shaped, equipped with an asymmetrically bifid crown, and being highly variable in shape and size. Light microscopy and scanning electron microscopy revealed the details of some aspects of this diversity, in addition to tooth morphology, intraspecific variability and wearing patterns. The ontogenetic sequence of simple conical teeth in embryos to the fully developed scraping teeth in adults is discussed, as well as the growth of each individual tooth and the recruitment of new teeth rows that replace worn and lost teeth. The inner surface of the lower lip is exposed to the substrate too, and is covered by a varying number of papillae bearing the unicellular unculi. These brush-like structures are as diverse as the teeth themselves, and are hypothesized to assist in the scraping of fine material, like encrusted algae. Analogous to teeth, these epidermal brushes may be shed when worn. The loricariid teeth and unculi are less studied morphological features, even though they are extremely decisive characters determining the feeding and specialization abilities of the members of this largest neotropical fish family.