Hysterothylacium sp.

Intestine.

MICHOACÁN: El Infiernillo: Ictalurus balsanus, Oreochromis aureus, Poeciliopsis balsas (110). TABASCO: Usumacinta (Tenosique): Ictalurus furcatus (62).

Note: Specimens collected in both States were included in the genus Thynnascaris, which is considered as a synonym of Hysterothylacium (28). Nematodes from Michoacán were identified as Thynnascaris habena (Linton) (110); however, this record was considered doubtful after voucher specimens were examined (149). A recent study pointed out several discrepancies between Mexican specimens and Linton’s original description, and for this reason these nematodes were considered as belonging to Hysterothylacium sp.(50).