A new species of Dermopristis Kearn, Whittington & Evans-Gowing, 2010 (Monogenea: Microbothriidae), with observations on associations between the gut diverticula and reproductive system and on the presence of denticles in the nasal fossae of the host Glaucostegus typus (Bennett) (Elasmobranchii: Rhinobatidae)

Abstract

Dermopristis cairae n. sp. (Monogenea: Microbothriidae) is described from the skin and possibly from the nasal fossae of the giant shovelnosed ray Glaucostegus typus (Bennett). The new species is distinguished from D. paradoxus Kearn, Whittington & Evans-Gowing, 2010 by its larger size, body shape, lack of transverse ridges on the ventral surface and absence of a seminal receptacle. Extensive short gut branches lie dorsal to the testes and adjacent to the coiled region of the vas deferens and the oötype, possibly reflecting high metabolic demand in these areas. Denticles are present in the lining of the nasal fossae of G. typus, providing a firm substrate for the cement-based attachment of a microbothriid. However, confirmation that D. cairae inhabits the nasal fossae of G. typus is required.

Spermatophores in Dermopristis cairae Whittington et Kearn, 2011 (Monogenea, Microbothriidae)

“…A striking feature of the anatomy of these parasites is the lack of a recognisable male copulatory organ (penis or cirrus) and the relatively spacious lumen and glandular wall of the male reproductive tract Kearn 2011). These features are consistent with spermatophore assembly and spermatophore exchange as a means of cross insemination.…”

“…The microbothriid monogeneans Dermopristis paradoxus Kearn, Whittington et Evans-Gowing, 2010 and D. cairae Whittington et Kearn, 2011 are ectoparasites of Pristis microdon (Elasmobranchii, Pristidae) and Glaucostegus typus (Elasmobranchii, Rhinobatidae) respectively. A striking feature of the anatomy of these parasites is the lack of a recognisable male copulatory organ (penis or cirrus) and the relatively spacious lumen and glandular wall of the male reproductive tract Kearn 2011).…”

“…These features are consistent with spermatophore assembly and spermatophore exchange as a means of cross insemination. No spermatophores were found associated with specimens of D. paradoxus (see Kearn et al 2010), but Whittington and Kearn (2011) found fusiform capsules attached externally to the ventral surfaces of some adult specimens of D. cairae (see Whittington and Kearn 2011, Fig. 4).…”

“…4). Whittington and Kearn (2011) considered the possibility that the capsules were eggs. Although no eggs were observed, the size and shape of the ootype indicated that the eggs of D. cairae are significantly smaller than the external capsules and are probably tetrahedral.…”

“…The conundrum is to resolve 2 alternative options. First, are the spermatophores of D. cairae noted by Whittington and Kearn (2011) recently received from another individual or second, are they freshly assembled and in the process of being offered to a potential mate? It was found necessary to resort to sectioning in an attempt to solve this problem.…”