Discussion of Related Species in North American Canids and Mustelids

Specimens of Filaroides milksi Whitlock, 1956 removed from the same lung tissue as were the type specimens were re-examined. Because of morphological features similar to those found in the genus Andersonstrongylus Webster, 1978 and inconsistent with those in Filaroides van Beneden, 1850, F. milksi is removed from the latter and placed in Andersonstrongylus as A. milksi (Whitlock, 1956). All available specimens of A. milksi from North American and Belgian canids and mustelids were re-examined. The only valid report of A. milksi is that of Whitlock (1956) in dogs; other reports being either presumptive, misidentified or the material is no longer available. The filaroidid and angiostrongylid nematodes of North American skunks are either respectively Filaroides mephitis Webster, 1967 or Andersonstrongylus captivensis Webster, 1978. The members of the genus Filaroides van Beneden, 1858 are all small fragile nematodes and it is only on rare occasions that complete specimens can be teased from the lung tissue in which they are embedded. Because of this, the morphological features necessary for identification are often destroyed. When present, they are so small that they may be overlooked or misinterpreted. This has led to some confusion in the systematics of this genus and its relatives. Recently there has arisen some uncertainty over the identity of certain filaroidid and angiostrongylid nematodes in North American carnivores, in particular the occurrence of Filaroides milksi Whitlock, 1956 in various host species. A restudy of specimens teased from the same lung tissue from which Whitlock's types were obtained revealed morphological characters inconsistent with the other members of the genus Filaroides but similar to those of Andersonstrongylus Webster, 1978. Accordingly, F. milksi is transferred to Andersonstrongylus as A. milksi n. comb. Representative specimens from all known infections of A. milksi in North America were requested. Nematodes were cleared in a phenol-alcohol solution which was replaced with glycerin. Drawings were made with the aid of a Zeiss drawing tube. Andersonstrongylus milksi (Whitlock, 1956) n. comb. (Figs. 1, 4a) Filaroides milksi Whitlock 1956. DESCRIPTION: As in Whitlock (1956) with the exception of the caudal end of the male. Tail of male usually curved ventrally. Bursa present. Bursal rays short but distinct; ventral rays divided approximately Vi their length; lateral rays arising from a common stalk and separated at the ends; dorsal ray reduced to a single pair of minute sessile papillae. TYPE HOST AND LOCALITY: Canis familiaris, Geneva, N.Y., USA. SPECIMENS EXAMINED: USNM Helm. Coll. 74734, NMCIC(P) 1980-137.