Joellina dosiniformis, Cosel, 2006

Cosel, Rudo von, 2006, Taxonomy of tropical West African bivalves. VI. Remarks on Lucinidae (Mollusca, Bivalvia), with description of six new genera and eight new species, Zoosystema 28 (4), pp. 805-851 : 843-845

publication ID	https://doi.org/ 10.5281/zenodo.4689802
DOI	https://doi.org/10.5281/zenodo.4892997
persistent identifier	https://treatment.plazi.org/id/666D2443-3E74-FF86-07D2-FAD8B092CADC
treatment provided by	Felipe
scientific name	Joellina dosiniformis
status	sp. nov.

Treatment

Joellina dosiniformis n. sp.

( Figs 23 View FIG ; 24 View FIG )

TYPE MATERIAL. — Holotype: N Angola, Angola margin, W of Ambrizete , 7°18.42’S, 12°04.60’E, 360- 367 m, trawled RV Thalassa, ZAIANGO BIOL 2, stn CP 09, 29.VIII.2000, leg. R. von Cosel, right valve ( MNHN). GoogleMaps

Paratypes: same locality, 1 rv., 3 lv. ( MNHN) ; 1 rv. ( BMNH).

TYPE LOCALITY. — Ambrizete, Northern Angola, tropical West Africa.

ETYMOLOGY. — The name characterizes the shell outline reminiscent of a Dosinia .

DISTRIBUTION. — Only known from the type locality.

DESCRIPTION

Shell to 32 mm long, somewhat variable in outline, rather thick and solid, equivalve, compressed, subcircular, oblique towards posterior, hardly longer than high to almost as long as high, length/height ratio 1.0-1.1. Umbones not prominent and hardly protruding, directed forward, beaks well in front of the vertical midline. Anterior part short and broad, anterior margin in its upper part almost straight to hardly indented, with a rather broadly rounded antero-dorsal corner to the lunular area. Ventral margin well rounded and evenly convex. Posterior part broad and high, posterior margin obliquely truncated, postero-dorsal corner protruding towards posterior, rounded but pronounced, postero-ventral corner broadly rounded and more indistinct.

Exterior with irregularly and rather widelyspaced commarginal lamellae and dense and very irregular growth lines and wrinkles and coarser growth stages. Anterior angle almost absent, anterior radial depression sharply cut in, irregular, otherwise antero-dorsal area ill-defined. Posterior angle rounded, posterior radial depression broad and ill-defined. Lunule small and very short, narrow, asymmetric, deeply sunken; escutcheon very narrow, entirely filled by the ligament and delimited by a sharp keel.

Ligament short, broad and deeply sunken.

Hinge plate broad, strong, with long posterior part. Hinge in the right valve with a very small single cardinal which may be reduced to a rudimentary knob and a small but well marked anterior lateral. Left valve with a socket for the cardinal knob of the right valve and the vestiges of anterior and posterior laterals. Anterior adductor scar large with long and broad diverging part, the pallial line meeting the scar two thirds above its middle or slightly less. Posterior adductor scar rather large. Inner margin smooth.

Valves presumably white in life but the dead collected samples are light greyish. Periostracum thin, greenish brown, when still present.

Measurements are provided in Table 12.

BIOTOPE

As for Graecina karinae n.gen., n. sp. Only single valves taken.

REMARKS

As for the genus. This species is characterized by the strong resemblance of its outline to certain species of the venerid genus Dosinia Scopoli, 1777 with high posterior part (e.g., Dosinia erythrea (Römer, 1860)) and also the large hinge plate and the anteriorly placed, non-protruding umbones add to this resemblance. No other lucinid is known to have this combination of characters.