Meeting Abstract

P3.33  Wednesday, Jan. 6  Insights into the Kytorhynchidae ("Typhloplanoida": Platyhelminthes) from the marine sediments of Sardinia LAUMER, Christopher E.; Harvard University Museum of Comparative Zoology

During an investigation of sublittoral marine sediments and other habitats from three localities in Sardinia, a considerable number of small flatworms related to the enigmatic Kytorhynchidae were encountered, which probably represent new species. This group evinces a minuscule but functional “false” proboscis whose structure has led some authors to suggest its relationship to the more-developed proboscis of the eponymous Kalyptorhynchia; hence, these are phylogenetically important animals. Nonetheless, the taxonomy of this cosmopolitan family remains in a primitive state. Abundant material was collected from several localities of two seemingly related new species of Kytorhynchus, distinguishable on the basis of the shapes of their sclerotized penis stylets, their gonopores, and other anatomical features readily visible on live animals; a description is of these animals is forthcoming. Both species display a combination of characters which prevents their placement into either of Rieger's (1974) subgenera; assignment to a subgenus, new or old, is eschewed until such time as an explicit cladistic analysis can be performed on the Kytorhynchidae. Also discussed (but too lacking in material to be formally described) are an aberrant Kytorhynchus with a single testis known from two individuals, as well as a Kytorhynchella with a very large, ornate penis stylet known from a single individual. Given the seeming Mediterranean endemicity of these animals, the relative ease with which they were discovered, and their scarce coverage in the literature, it seems reasonable to conclude that zoologists today understand only the barest fraction of the diversity of these little worms.