Tugonia (Tugonia) huanghaiensis Xu, 1987

Zhang, Jun-Long, Xu, Feng-Shan & Liu, Rui-Yu, 2012, The Myidae (Mollusca, Bivalvia) from Chinese waters with description of a new species, Zootaxa 3383, pp. 39-60 : 51

Tugonia (Tugonia) huanghaiensis Xu, 1987

Figure 6A–K

Tugonia huanghaiensis Xu, 1987: 437 –438 & 441, fig. 1a—Bernard et al. 1993: 107; Xu 1997: 230; Lutaenko & Xu 2008: 52, text-fig. 6E, pl. 5, figs. A–D; Xu & Zhang, 2008: 257, fig. 815; Xu, 2008: 590.

Cryptomya (Venatomya) semistriata ( Hanley 1842) — Huber (2010): 766.

Material examined. MBM no.73M-030 (Holotype) (1 articutate shell), Jiaozhou Bay, China, collected by Qi Zhong-yan, on October 30th, 1973; MBM no.57M-101 (not no.56M-101 by Xu 1987) (Paratype) (1 articutate shell), in sand, Rudong, Jiangsu Province, China, collected by Ma Xiu-tong, on June 10th, 1956.

Distribution and habitat. Recent. Jiaozhou Bay, China; Rudong, Jiangsu Province, China. Habitat unknown.

Type locality. Jiaozhou Bay, China.

Diagnosis. Length to 20 mm; shell globose; umbo prominent, situated subcentral and prosogyrate; periostracum yellowish; sculpture with fine radial ribs, somewhat stronger posteriorly; posterior area incipiently rostrate, with only commarginal lines; pallial sinus not reaching further anterior than posterior adductor scar; pallial line thin or obscure.

Remarks. Huber (2010) thought this species is the synonym of Cryptomya (Venatomya) semistriata ( Hanley 1842) . Swennen et al. (2001) recognized Tugonia semistriata ( Sowerby II, 1875) [sic] as a synonym of T. princeps A. Adams, 1851 . But judged from the figures by Sowerby II (1875: pl. 2, fig. 6a, b) and Swennen et al. (2001: p. 97, fig. 209), C (V.) semistriata has a deeper pallial sinus whereas it is diminutive in T. (T.) huanghaiensis . In addition, the ventral margin of T. (T.) huanghaiensis is much more convex than in C. (V.) semistriata , and its umbo is much larger and more inflated.

Figures

FIGURE 6. A – K. Tugonia (Tugonia) huanghaiensis Xu, 1987. A – F, holotype, MBM no. 73 M- 030, length = 19.8 mm. A. Exterior of right valve. B. Exterior of left valve. Scale bar (A, B) = 2 mm. C. Hinge of left valve. Scale bar = 2 mm. D. Interior of right valve. E. Interior of left valve. Scale bar (D, E) = 2 mm. F. Close up of surface sculpture. Scale bar = 2 mm. G – K, paratype, MBM no. 57 M- 101, length = 16.2 mm. G. Exterior of right valve. H. Exterior of left valve. Scale bar (G, H) = 5 mm. I. Hinge of left valve. Scale bar = 2 mm. J. Interior of right valve. K. Interior of left valve. Scale bar (J, K) = 5 mm. L. Tugonia (Distugonia) decurtata (A. Adams, 1851). From Okutani (2000: pl. 508, fig. 4, with permission from author).