Corynosoma semerme ( Forsell, 1904 ) Lühe, 1911

Leidenberger, Sonja, Boström, Sven & Wayland, Matthew T., 2019, Morphological observations on three Baltic species of Corynosoma Lühe, 1905 (Acanthocephala, Polymorphidae), European Journal of Taxonomy 514, pp. 1-19 : 8

Corynosoma semerme ( Forsell, 1904) Lühe, 1911

Figs 5–6 , Table 2

Diagnosis

Corynosoma semerme is characterised by a body 1.83–3.13 mm long in females and 1.91–2.73 mm long in males, a robust trapezoid neck structure, spines covering most of fore-trunk, spines covering entire ventral surface of hind-trunk, proboscis with 22–25 longitudinal rows of hooks with 10–12 hooks in each row in females and 22–24 longitudinal rows of hooks with 10–14 hooks in each row.

Material examined (see Table 1 and Fig. 1 )

SWEDEN • 14 ♀♀; Stocka/ Gävleborgs Province , Bothnian Sea; SMNH-162974 • 10 ♂♂; same data as preceding; SMNH-162975 • 6 ♂♂; Hudiksvall/Gävleborgs Province, Bothnian Sea ; SMNH-162976 .

Figures

Fig. 5. SEM micrographs of Corynosoma semerme from grey seals, Halichoerus grypus, in the Swedish Baltic Sea. a. ♀, entire worm, ventro-lateral view, from the Bothnian Sea, Hälsingland, Stocka. Spines cover the entire ventral surface of the hind-trunk. b. ♂, whole worm, ventral view, from the Bothnian Sea, Hälsningland, Stocka. Ventral spination of the entire hind-trunk and numerous genital spines. c. Proboscis of a ♀, ventral view, showing the arrangement of the hooks. d. Base of proboscis of a ♀, lateral view, showing the spineless neck and the posterior and middle series of hooks. e. Anterior end of proboscis of a ♀ showing the bare tip. f. Trunk spines of the fore-trunk of a ♂, ventral view. g. Posterior end of a ♀ showing the trunk-spines that extend over the ventral surface as far as the gonopore. h. Posterior end of a ♂ with numerous genital spines.

Fig. 6. Variation in the morphology and size of copulatory caps found on ♀ Corynosoma semerme from a ringed seal, Pusa hispida, in the Swedish Baltic Sea. Images are maximum intensity projections of confocal image stacks. The copulatory caps show strong autofluorescence when excited with a 405 nm laser. All scalebars represent 200 µm.

Fig. 1. Map of sampling localities.