Andracantha sp.

Lisitsyna, O. I., Kudlai, O., Spraker, T. R. & Kuzmina, T. A., 2018, New Records On Acanthocephalans From California Sea Lions Zalophus Californianus (Pinnipedia, Otariidae) From California, Usa, Vestnik Zoologii 52 (3), pp. 181-192 : 185

Andracantha sp.

Description ( figs 1 , E; 2 , A, B, C, H, J; table 2).

General. Relatively small acanthocephalans. Trunk with discoid widening and two fields of spines in anterior part. Anterior field of spines broadest on ventral surface, narrow dorsally ( fig. 2 , A, C). Posterior field of spines broadest ventrally. Bare zone between fields of spines widest ventrally (265–488), often narrowing and ending near dorsal surface. In anterior field of spines, length of spines decreasing from apical (28–43), to basal (24–29). In posterior field of spines, length of spines increasing from apical (22–29) to median (35–43) and decreasing posteriorly (23–33). Posterior end of females with genital spines, posterior end of males without spines ( fig. 2 , A, C). Proboscis almost cylindrical, with dilatation in posterior third, with 15–17 longitudinal rows of 10–15 hooks in each ( fig. 2 , B, J). First 6–9 hooks large, with strong roots directed posteriorly. Next 4–6 hooks spiniform, without roots. Proboscis receptacle double-walled, with cerebral ganglion in its anterior third. Neck distinct. Lemnisci sacciform, 828–920 long, attached in neck, not reaching level of proboscis receptacle bottom.

Remarks. The genus Andracantha now comprises nine valid species ( Schmidt, 1975; Amin, 2013; Presswell et al., 2017). The specimens found in the present study closely resemble Andracantha baylisi ( Zdzitowiecki, 1986) based on the shape and size of the body and hooks, arrangement of the tegumental spines and location of the gonopore in females. However, they differ from A. baylisi in the armature of the proboscis (15–16 rows of 10– 13 hooks each in females and 15–17 rows of 13 hooks each in males vs 16 rows of 10– 11 hooks in both sexes in A. baylisi ), the presence of bare zone between two fields of spines in the anterior part of the trunk, and a peculiar system of muscles in the posterior part of the female trunk ( Zdzitowiecki, 1985, 1986, 1989). A complex system of foretrunk muscles was described in the species of the genera Andracantha and Corynosoma ( Aznar et al., 2006) ; however these muscles in the area of female genital system were not studied. In our specimens of Andracantha sp. , the muscles which support female genital system ( fig. 2 , H), possibly, act as ligaments.

Due to the presence of only immature individuals of both sexes in our material, a formal description of this putative new species was impossible, and requires examination of the mature specimens.

Figures

Fig. 1. Acanthocephalan species from California sea lions (Zalophus californianus): A — Corynosoma strumosum, total view of adult male; B — Corynosoma obtuscens, total view of female; C — Profilicollis altmani, total view of immature male; D — Andracantha phalacrocoracis, anterior part of female; E — Andrcantha sp., total view of immature female. Scale bars: A, B, C, E — 1 mm, D — 500 μm.

Fig. 2. Acanthocephalan species from California sea lions (Zalophus californianus): A — Andracantha sp., total view of immature male. Scale bar 1 mm; B — Andracantha sp., proboscis of female. Scale bar 500 μm; C — Andracantha sp., total view of immature female. Scale bar 1 mm; D — Andracantha phalacrocoracis, spines of ventral surface. Scale bar 1 mm; E — Corynosoma obtuscens, transitional hooks. Scale bar 50 μm; F — Corynosoma strumosum, transitional hooks. Scale bar 50 μm; G — Profilicollis altmani, longitudinal row of hooks. Scale bar 100 μm; H — Andracantha sp., posterior part of female. Scale bar 500 μm; J — Andracantha sp., longitudinal row of hooks.Scale bar 100 μm; K — Andracantha phalacrocoracis, longitudinal row of hooks. Scale bar 100 μm.