Feeding in ophiuroids from Argentina: analyses of teeth microstructure and jaw morphology

BERECOECHEA, J.J.; BOOS, K.; BROGGER, MARTÍN IGNACIO

Bruselas

Congreso; 14th International Echinoderm Conference; 2012

Feeding strategies have been mainly studied in ophiuroid class. Many researches have been conducted by stomach content analysis, field observation, laboratory experiments and analysis of stereom microstructure of teeth and jaw morphology. Last ones have been poorly studied. Nevertheless, different types and functional teeth have been described. For some species, the tooth stereom is completely fenestrated, these are called ?uniform?; in others, the base is fenestrated while the distal edge is composed of imperforate calcite, called ?compound? teeth. ?Intermediate? teeth were recently reported for some specie, presenting variations in the compaction of calcite. Also different life styles are related to different feeding mechanisms. Within a framework of comparative study of ophiuroids stereom microstructure of teeth and feeding strategies, a research was developed on 9 specie from Argentinean sea. Microstructure of teeth and oral plates was analyzed by Scanning Electron Microscope. Results show that: Gorgoncephalus chilensis, Ophiomyxa vivipara, Ophiocten amitinum, Ophiacantha vivipara and Ophiuroglypha lymani have uniform teeth, corresponding with macrophagous feeding, whereas Amphiura magellanica, and Amphipholis squamata have compound teeth, corresponding in microphagous feeding. Ophioplocus januarii and Ophiactis asperula have been reported as intermediate teeth, having an omnivorous diet. From each specie studied, analysis in different life stages was made, resulting in almost the same microstructure and shape oh teeth and oral plates. Although, variations in the number of teeth and oral papillae were observed, probably resulting by growth of teeth and dental plate. On the basis of the analysis of the microstructure of teeth and morphological features of jaws, relationships between life styles and microstructure were inferred. Results of this research expand knowledge of feeding mechanisms in ophiuroidea from Argentina. However more specie remain to be studied.