Decatopecten G. B. Sowerby II, 1839

Dijkstra, Henk H. & Beu, Alan G., 2018, Living Scallops of Australia and Adjacent Waters (Mollusca: Bivalvia: Pectinoidea: Propeamussiidae, Cyclochlamydidae and Pectinidae), Records of the Australian Museum (Rec. Aust. Mus.) 70 (2), pp. 113-330 : 185

Decatopecten G. B. Sowerby II, 1839

Decatopecten [Rüppell] Sowerby, 1839: 37, 78, 121, fig. 172. Type species (by monotypy): Pecten [sic] plica Linnaeus, 1758 (= Ostrea plica Linnaeus, 1758 ). Recent, Indonesia (see Dijkstra, 1999: 404).

Pallium Schumacher, 1817: 41 , 120 (junior homonym of Pallium Schröter, 1802 ). Type species (by monotypy): Pallium striatum Schumacher, 1817 (= Ostrea plica Linnaeus, 1758 ). Recent, Indonesia.

Decadopecten Swainson, 1840: 388 . Type species (by monotypy): Pecten plicata [sic] Sowerby, 1839, error for Pecten plica Sowerby, 1839 (junior homonym of Pecten plicata [sic] J. de C. Sowerby, 1829).

Dentipecten Gray, 1847: 200 (no diagnosis, obj.). Type species (by original designation): Ostrea plica Linnaeus, 1758 .

Comptopallium Iredale, 1939: 359 . Type species (by original designation): Comptopallium pauciplicatum Iredale, 1939 [= Ostrea radula Linnaeus, 1758 ]. Recent, Queensland. See Waller (1986: 40).

Comments on synonymy. Decadopecten is an incorrect subsequent spelling of Decatopecten (ICZN, 1999: 42, Article 33.3). See also Hertlein (1969: N365).

Diagnosis. Elongate plicate Decatopectinini with closely spaced commarginal lamellae and delicate antimarginal microsculpture in early ontogeny, and with secondary radial sculpture in late ontogeny; hinge dentition dominated by prominent dorsal and/or intermediate teeth; resilial teeth obsolete or absent; byssal notch small, ctenolium weak; internal plicae with short carinate edges near margin.

Distribution. Miocene–Recent (Hayami, 1989: 15). The earliest record is probably Pliocene, even if one accepts the synonymy of Comptopallium (pers. comm. D. Jablonski, 2017). (Sub)tropical Indo-West Pacific, living in the littoral to sublittoral zones on soft sediment.

Discussion. Grau (1959: 366) and later Hertlein (1969: N366) placed Comptopallium in the synonymy of Semipallium Lamy, 1928 . However, Waller (1972a: 245) indicated that this is unacceptable, based on differences in shell microsculpture. Waller (1986: 40) treated Comptopallium as a junior synonym of Decatopecten , and ( Waller, 1991) placed Semipallium in Chlamydini (i.e., Pedini ). Several recent phylogenies (Alejandrino et al., 2011; Sherratt et al., 2016; Serb, 2016) show species assigned to Bractechlamys and Decatopecten as intermingled, suggesting that the relationships of these genera need revision, and possibly that Comptopallium deserves recognition, but this is beyond the scope of the present review.