Ascaridoid nematodes of amphibians and reptiles: Multicaecum and Brevimulticaecum.

Abstract

The genus Multicaecum Baylis 1923, sensu Hartwich 1957, was found to be heterogeneous, comprising species which are released to two distinct genera, namely Multicaecum Bavlis, 1923 and Brevimulticaecum. The latter name is derived from the subgenus Brevinulticaecum Mozgovoy, in Skrjabin, Shikhobalova, and Mozgovoy, 1951 by raising it to generic rank and emending the definition. Multicaecum contains a single species, agile Wedl, 1861 occurring in Crocodylus spp. in Africa, India and Australia, and is characterized by smooth rounded lips, each with a dentigerous ridge comprising small sharp denticles. The excretory pore is level with the nerve ring or behind it, and the ventricular appendices are long and slender. The species gangeticum Maplestone 1930 and quadrata Linstow 1904 are excluded from Multicaecum and regarded as species inquirendae incertae sedis. Brevimulticaecum contains five species occurring in the caimans and the alligator of the New World: baylisi Travassors, 1933 (type species; acuticauda Schuurmans-Stekhoven, 1937 is placed in synonomy under baylisi); stekhoveni Baylis, 1947; tenuicolle Rudolphi, 1819; and two new species. Brevimulticaecum spp. are characterized by flat lips with alate margins and notches, without dentigerous ridges, excretory pore in front of or at nerve ring and the ventriculus with short appendices. The significance of this proposal is discussed in relation to the other genera of ascaridoid nematodes in crocodilians.