Parvamussium formosum (Melvill in Melvill & Standen, 1907)
MELVILL, J. C. & R. STANDEN. 1907. The Mollusca of the Persian gulf, gulf of Oman and Arabian Sea as evidenced mainly through the collections of Mr. F. W. Townsend, 1893 -1906, with descriptions of new species, Part 2. Pelecypoda. Proceedings of the Zoological Society of London, 54: 783-848, pls. 53-56. [p. 807, pl. 55, fig. 7]
1907 Amussium [sic] formosum Melvill in Melvill & Standen, 1907
J. C. Melvill & R. Standen, 1907,
plate 55. |
«A. testa parva, tenuissima, albida, subpellucida, inaequivalvi; valva sinistra majore, fere Iaevi, costulis radiantibus evanidis, auriculis inaequalibus, pulchre in utraque valva cancellatis; valva dextra sub lente concentrice delicatissime lirata; pagina interna costis ad 10-12 instructa, haud ad marginem valvae sinistrae productis.
Alt. 9, lat. 8.50, diam. (valvae sinistrae maj.) 1 mm. Hab. Persian Gulf: Gulf of Oman. Lat. 24° 58' N., long. 56° 54' E.; 156 fathoms. Allied to A. siebenrockii Sturany, but much smoother, with rudimentary radiating ribs only; there is also no sign of cancellation on the left valve; the right valve is much the smaller, and is microscopically concentrically lirate. The internal white ribs, ten to twelve in number, are not produced to the ventral margin, as is the case in A. siebenrockii. Many examples, but mostly in imperfect condition.» JAMES COSMO MELVILL, 1907
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«Description: Shell small, up to 9.8 mm high, semi-transparent, subcircular, somewhat higher than wide, inequivalve, left valve slightly more convex than right valve, equilateral, auricles unequal, umbonal angle 105°, colour whitish. Left valve nearly smooth (central part of disc) or weakly sculptured with numerous, irregularly spaced, fine antimarginal lirae, somewhat more prominent near anterior and posterior margins, some specimens with very weak commarginal lamellae. Anterior auricle larger than posterior sculptured with fine, close-set antimarginal and commarginal lamellae; posterior auricle nearly smooth or sculptured with very weak antimarginal lirae. Right valve with very weak, regularly spaced, commarginal lirae. Anterior auricle with fine commarginal or reticulate sculpture, posterior auricle smooth or with very fine commarginal lirae. Byssal notch moderately deep, byssal fasciole rather small, no ctenolium. Hinge line straight. Resilifer triangular. Internal ribs usually 10 (some specimens with 1–3 rudimentary interstitial riblets) and 1 anterior and 2 posterior auricular riblets. Internal ribs commencing in late growth stage and extending to submarginal area. Internal posteriorly placed ribs on left valve somewhat oblique.
Distribution: Red Sea, Gulf of Aden, Arabian Gulf and Persian Gulf. Sublittoral to bathyal depths. Living on soft sediments (mud, muddy sand). Remarks: The present specimens from the Gulf of Aden are identical to the type material, although somewhat more prominently sculptured on the left valve. For comparison with Parvamussium siebenrocki (STURANY1901) see DIJKSTRA & KNUDSEN (1998: 46).» DIJKSTRA, H. H. & A. W. JANSSEN. 2013. Bathyal and abyssal Pectinoidea from the Red Sea and Gulf of Aden (Bivalvia: Propeamussiidae, Entoliidae, Pectinidae). Archiv für Molluskenkunde, 142 (2) 181-214, figs. 1-57. [p. 192]
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Parvamussium formosum (Melvill in Melvill & Standen 1907); H. H. Dijkstra & A. W. Janssen, 2013, Bathyal and abyssal Pectinoidea from the Red Sea and Gulf of Aden, figures 20, 22.
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