Somalipecten Waller, 1986
WALLER, T. R. 1986. A new genus and species of scallop (Bivalvia: Pectinidae) from off Somalia, and the definition of a new tribe Decatopectinini. The Nautilus, 100 (2): 39-46, figs. 1-13. [p. 41]
«Family Pectinidae Rafinesque, 1815
[emend., Waller, 19781 Subfamily Pectininae Rafinesque, 1815 Tribe Decatopectinini, new tribe [...]
Somalipecten Waller, new genus
Type Species: Somalipecten cranmerorum Waller, new species, from off Somalia, depth 150 to 300 m.
Diagnosis: Plicate Decatopectinini having both valves convex, byssal notch only moderately deep, left umbo only slightly convex or flattened, and disk with uneven curvature, incipient ledging, or widely spaced nodes at least in early ontogeny; secondary radial costae present distally; auricular costae on right posterior auricle weakly developed and few in number or absent; enlarged scales, if present, limited to left valve; dentition dominated by dorsal teeth, intermediate teeth weak, resilial teeth commonly absent.
Taxonomic Content: The new genus includes a number of fossil species from the western Indian Ocean region described in publications by Cox (1929) and Eames and Cox (1956): Chlamys (Aequipecten) farsanensis Cox, 1929, C. (A.) isthmica (Fuchs, 1878), C. (A.) leesi Cox, 1929, C. (A,) lessepsi (Fuchs, 1878), C. (A.) pseudola Eames and Cox, 1956, C. (A.) werthi (Philippi, 1901), and C. (A.) wyllei Cox, 1929.
Stratigraphic Range: Upper Miocene to present. All of the fossil species listed above, with the exception of S. pseudola, are from deposits adjacent to the Red Sea (Egypt, Sudan, Saudi Arabia), the western Indian Ocean (Somalia, Kenya, Tanzania, Zanzibar), and the Arabian Sea (southeastern Saudi Arabia, Iran). Their age was called "post-Miocene" by Cox (1929), and some are probably as young as late Pleistocene or Holocene. S. pseudola from Iran was said by Eames and Cox (1956) to range from Upper Miocene to Pliocene. Somalipecten cranmerorum, new species, is the only known living species.
Comparison: A somewhat flattened left umbo is also present in Annachlamys, which differs from Somalipecten in having a wider umbonal angle, in having commarginal lamellae which revert to a far-set condition late in ontogeny, and in lacking nodes, enlarged scales, or extensive secondary radial costae. Some members of Bractechlamys, specifically B. langfordi (Dall, Bartsch, and Rehder, 1938) and B. noduliferum (Sowerby, 1842), have nodes and ledges but differ from Somalipecten in having persistent deep byssal notches, strong intermediate teeth, and strong costae on all auricles. Extant Nodipecten Dall, 1898, and fossil Lyropecten Conrad, 1862, and Macrochlamis Sacco, 1897, differ in having far-set commarginal lamellae and much stronger intermediate hinge teeth. Flexopecten of the Mediterranean and eastern Atlantic differs in hinge details, the right dorsal teeth being much weaker or absent, and lacks nodes or enlarged scales. Mirapecten maintains a deep byssal notch throughout ontogeny and has enlarged scales gn at least the posterior plica of both valves. Notochlamys Cotton, 1930, differs from Somalipecten in having persistent shagreen microsculpture, and Mesopeplum differs in having far-set cornmarginal lamellae and and posterior by a single lower plica, the prominent resilial teeth.»
THOMAS RICHARD WALLER, 1986
|
Somalipecten cranmerorum Waller; T. R. Waller, 1986, A new genus and species of scallop (Bivalvia: Pectinidae) from off Somalia, and the definition of a new tribe Decatopectinini, figures 1-13.
|
Mirapecten cranmerorum (Waller, 1986); B. K. Raines & G. T. Poppe, 2006, A Conchological Iconography, The Family Pectinidae, plate 76, figures 1-4.
|
«Remarks: Hertlein (1969: N366) treated Mirapecten as a subgenus of Semipallium [Jousseaume] Lamy, 1928, which he referred to the same suprageneric group as Decatopecten. Waller (1986: 40), followed by Vaught (1989: 119), considered Mirapecten as a full genus in the tribe Decatopectinini. Somalipecten was originally differentiated from Mirapecten by the presence in the latter taxon of a deep byssal notch throughout ontogeny and of well-developed scales on its radial plicae (or at least on the posterior plica of both valves). However even within different species of Mirapecten these characters vary, so that the byssal notch may be deep or only moderately deep, and scales range from well developed to absent.»
DIJKSTRA, H. H. & R. N. KILBURN. 2001. The family Pectinidae in South Africa and Mozambique (Mollusca: Bivalvia: Pectinoidea). African Invertebrates, 42: 263-321, figs. 1-55. [p. 283]
|