Falcaustra chabaudi sp. n. (Nematoda: Kathlaniidae) from the Western Lesser Siren, Siren intermedia nettingi Goin, 1942

Abstract

Falcaustra chabaudi sp. n. is described from 7 males and 10 females collected from the large intestine of the western lesser siren, Siren intermedia nettingi, in southern Illinois. This species most closely resembles F. cryptobranchi (Walton, 1930) Freitas and Lent, 1941, from which it differs by the absence of grooves spiraling part-way around the head, in the conformation of the anterior esophageal bulb, and in having spicules 1.21 to 1.34 mm long. F. chabaudi is differentiated from F. catesbeianae Walton, 1929, the only species in Falcaustra reported from the genus Siren. Seventeen undescribed kathlaniid nematodes, identified as members of the genus Falcaustra (= Spironoura), were found in the large intestine of two western lesser sirens, Siren intermedia nettingi Goin, 1942. A summary of the various species of this genus is included in the works of Freitas and Lent (1941), Chabaud and Golvan (1957), Walton (1964), and Khalil (1970). The material used for the following description was fixed in hot 70% ethanol, stored in 70% ethanol containing 5% glycerine, and cleared by standard glycerine dehydration technique. Specimens were temporarily mounted in pure glycerine and studied with light and phase contrast microscopes. All measurements are in microns unless otherwise indicated. Illustrations were made with the aid of a camera