Tugonia (Distugonia) decurtata ( A. Adams, 1851 )

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 : 53

Tugonia (Distugonia) decurtata ( A. Adams, 1851)

Figure 6 L

Sphenia decurtata A. Adams, 1851: 88 –89.

Cryptomy decurtata ( A. Adams, 1851) — A. Adams, 1868: 366; Beets, 1949: 273, 277; Beets, 1950: 17.

Mya decurtata ( A. Adams, 1851) — Sowerby, 1875: sp. 11, pl. III, fig. 11.

Distugonia decurvata ( A. Adams, 1851) — Habe, 1951: 75, pl. 12, figs. 15 & 16; Habe, 1961: 140, pl. 63, fig. 11; Habe, 1968: 205, pl. 63, fig. 11; Habe, 1977: 279, pl. 58, figs. 7 & 8; Wu, 1980: 189; Xu, 1997: 230; Xu, 2008: 590; Okutani, 2000: 1021, pl. 508, fig. 4 [spelling error].

Distugonia decurtata ( A. Adams, 1851) — Bernard et al. 1993: 107.

Tugonella decurtata ( A. Adams, 1851) — Huber, 2010: 461 (text-fig.).

Distribution and habitat. Miocene to Recent. Taiwan, China; Japan; Philippines. Intertidal mud bottom to 50 m.

Type locality. Catanuan, Province of Tayabas, Island of Luzon, in sand at low water depths.

Diagnosis. Length to 30 mm; shell slightly inflated, elongate-oval; umbo prominent, situated subcentral; posterior area demarcated by ridge; chondrophore projecting in the left valve, right valve resilifer compressed; pallial sinus shallow, not reaching further anterior than posterior adductor scar; pallial line thin.

Remarks. This species had been incorrectly spelled as decurvata by some Japanese and Chinese authors.

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).