Hinnites spectabilis Cosel & Gofas, 1984
COSEL, R. VON & S. GOFAS. 1984. A new species of Hinnites (Bivalvia: Pectinidae) from Angola. Bollettino Malacologico, 20 (9-12): 297-306, pls. 1-4. [p. 298, (error: pl. 1, figs.1-4); pl. 2, figs. 1-3; pl. 3, figs. 1-2]
«Hinnites spectabilis n. sp.
Material examined
Holotype MNHN Paris, 120 x 105 mm, Baia de Santa Maria, Prov. Benguela, Angola, on rocks, 5 m. Paratypes: MNHN Paris, 92 x 92 mm (a lower valve), Moçâmedes, Angola, on underwater structure of a shipyard; MNHN Paris, 60 x 46 mm, Praia Amelia, Moçâmedes, Angola, on the inside of an old Patella shell, spring tide low water, 12.1981; MNHN Paris, 115 x 115 mm, 98 x 96 mm, 92 x 75 mm, 70 x 67 mm, 69 x 64 mm, all from Praia Amelia, Moçâmedes, Angola, 9. 1984; MNHN Paris, 86,4 x 90,5 mm, (an upper valve), Moçâmedes, Angola, Quaternary deposits; Museum de Mineralogia e Geologia, Universidade de Loanda, 84 x 82 mm (an upper valve), Moçâmedes, Angola, on underwater structure of a shipyard, 12.1981. Description Shell large, up to 120 mm, strong and moderately heavy, irregularly shaped according to the substrate, but generally more or less circular and, if only with small area attached, of similar height and width. Young regular "Chlamys" stage of the valves ca. 16-25 mm high and broad, with 20-30 very weak and smooth irregular radial ribs, and 1-4 riblets or threads in each interspace, part of these riblets becoming additional «regular» ribs in the later irregular growth stage (see below). Towards the umbones sculpture becoming obsolete. In adult specimens outside of upper (left) valve generally with numerous coarse, irregular, more or less wavy ribs (in holotype ca. 50 near the ventral margin) and irregular concentric growth lines. Radial ribs normally unequal in size, one in every 4-6 being more developed (pl. 2, fig. 1) some of the intercalated smaller ribs gradually catching up in size towards the ventral margin in the later growth stage (pl. 1, fig. 1). Scales on the ribs of the irregular growth stage reaching 1,5 mm. Surface of lower (right) attached valve depending on the contact with the substrate: with irregular concentric lamellae when attached to or overlying the substrate, with radial ribs like the upper valve on the free growing parts. Ears more or less distorted, byssus gap very shallow and in fully grown specimens hardly visible and without function. Interior with large adductor scar within a comparatively small area surroundeb by the pallial line. Hinge strong, hinge line straight or irregular, depending on the form of the substrate. Right (lower) valve slightlv larger than left valve, especially in fully attached specimens. Exterior colour of valves bright orange to deep violet or brick red. Interior yellowish, whitish with reddish stain of adductor scar or with a deep violet sector, or nearly entirely deep violet. Inner margin with an approximately 5-10 mm broad orange to brick red, reddish brown or purple zone; in the holotype this zone is seen clearly on the lower valve only, with an additional narrow deep violet fringe of ca. 3 mm directly along the ventral margin of the valve, in the upper valve the reddish zone is nearly entirely obscured by the violet colour of the interior, leaving visible only the narrow deep violet fringe along the ventral margin. Dark violet stain also along the hinge line. - Unattached part of the outer surface of adult specimens heavily incrusted with barnacles, polychaete tubes, oysters or smaller specimens of H. spectabilis, when the specimens are growing on exposed parts of the substrate. Locus typicus Baia de Santa Maria, Benguela, Angola. Distribution recent: hitherto only known from the short coast strip between Baia de Santa Maria and Moçâmedes in Southern Angola; fossil: Quaternary deposits near Moçâmedes Airport, altitude 50 m. Attributed to «Tyrrhenien». Habitat Infralittoral, from extreme low tide to a depth about 10 m, attached to hard substrate either exposed to light, or in crevices or under rocks, in moderately calm and very clear water. At the tvpe locality and in Praia Amelia, specimens are abundant, but most are attached by the entire lower valve and cannot be detached easily or not at all.» RUDO VON COSEL & SERGE GOFAS, 1984
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R. von Cosel & S. Gofas, 1984, plates 2, 3.
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