Entobdella steingroeveri ( Cohn, 1916 ) Johnston, 1929

Kearn, Graham C., Whittington, Ian D. & Evans-Gowing, Richard, 2007, A revision of Entobdella Blainville in Lamarck, 1818, with special emphasis on the nominal (type) species “ Entobdella hippoglossi (Müller, 1776) Blainville, 1818 ” (Monogenea: Capsalidae: Entobdellinae) from teleost flatfishes, with descriptions of three new species and a new genus, Zootaxa 1659, pp. 1-54 : 21

Entobdella steingroeveri ( Cohn, 1916) Johnston, 1929

( Figs. 19–25)

Seminal receptacles were observed in 2 of 3 whole mounts. Five receptacles were observed in 1 specimen and 4 in the other and 5 receptacles were visible in the sectioned specimen ( Fig. 19). Serial resin sections revealed that the proximal region of the vagina is loosely coiled ( Fig. 21) and that these coils make contact with the vitelline reservoir ( Fig. 20), not the seminal receptacles which are remotely situated from the vagina. This leaves little doubt that the vagina opens proximally into the vitelline reservoir, although the communication was not identified. Distal to this coiled vaginal region, the vagina follows a relatively straight path ( Fig. 22), although evidence of some minor deviations was occasionally seen ( Fig. 23). The lumen of the relatively straight vaginal tube is narrow (16 – 30 in diameter). In 1 whole mount, this region of the vagina was just detectable, contained material (sperm?) and had an external diameter of about 20. The wall of the vaginal tube is thin and stained relatively lightly with toluidine blue. The staining intensifies a little near the vaginal opening and intensely stained radiating structures (muscle?) are associated with the terminal region of the vagina ( Fig. 24). The opening on the ventral surface is tiny (diameter 2) in resin sections ( Fig. 24). No atrium, similar to that of “ E. hippoglossi type 2” ( Fig. 9) and no other specialised region of the distal vagina as in “ E. hippoglossi type 1” was observed.

The accessory sclerites of E. steingroeveri ( Fig. 15D) are similar in shape to those of “ E. hippoglossi ” and E. squamula . The mean ratio of lengths of the anterior hamuli and accessory sclerites of 3 relatively flat specimens was 1.75 ( Table 3).

Papillae are present on the entire ventral surface of the haptor ( Fig. 25) but were shown only on the posterior two-thirds of the organ in Cohn’s (1916) fig. 1. On the posterior half of the haptor, papillae lateral to the sclerites are arranged in radial rows (see Cohn’s fig. 1), whereas those between the 2 sets of sclerites appeared randomly arranged. The density of papillae is high: a mean of 186 per mm 2 (n = 5 estimates). Papillae are circular with diameters ranging from 25 to 65. Papillae with lobed apices were not found.

One of the adhesive pads was clearly subdivided into 3 subunits in an unmounted specimen viewed with reflected light. Eyes were described by Cohn (1916), but not drawn on his fig. 1. In 1 of our 3 mounted specimens, all 4 eyes were identified but were not conspicuous. In a second specimen, only the 2 posterior eyes were seen and no eyes were observed in the third specimen, although folding of the head region in these 2 specimens prevented a clear view.

Glands of Goto were seen in 1 mounted specimen.