Dichelyne robustus (Van Cleave & Mueller, 1932) Mueller, 1933

Synonym: Dacnitoides robusta Van Cleave & Mueller, 1932

Description (after Van Cleave & Mueller 1932). With characteristics of the genus. Body robust, with conspicuous cuticular thickening from oral region to beyond limit of oesophagus. Prominent pair of amphids or cephalic papillae near posterior limit of oesophagus. Oesophagus 0.38–0.43 long. Ventral intestinal caecum extends anteriorly almost to buccal cavity (Fig. 95 A).

Males: 4.25–4.50 long; width about 0.32. Pre-cloacal sucker absent. Four pairs of pre-cloacal and four pairs of post-cloacal papillae. One median and three pairs of lateral papillae just anterior to cloaca (Fig. 95 B). Spicules relatively short; when withdrawn they appear tubular but when extruded are broad, ribbon-like, with frilled tips. Gubernaculum apparently absent.

Females: about 5.0 long; width 0.47–0.51. Ovarian coils extend almost to anterior end of body (Fig. 93 A). Vulva short distance behind mid-body. Anus about 0.15 from tail tip. Pair minute lateral papillae in middle of postcloacal region. Tail bears spine with “the structure of a sensory papilla” (Fig. 95 C).

Comments: the original description of D. robustus is inadequate and, according to Caspeta-Mandujano et al. (1999), type specimens are not available in the US National Parasite Collection, Beltsville, Maryland—collections that have been transferred to the Smithsonian Institution, National Museum of Natural History (Washington, DC, USA). It seems that Maggenti (1971) was not first to transfer Dacnitoides robusta to Dichelyne as “ Dichelyne robusta ” [= Dichelyne robustus]. The n.comb. appears to have been first proposed by Mueller (1933). Site: intestinal lumen

Hosts: Ameiurus melas (2); Ameiurus nebulosus (1)

Distribution: Manitoba, Ontario

Records: 1. Bangham 1955 (ON); 2. Choudhury & Nadler 2016 (MB)