Pusillolucina biritika, Taylor, John D. & Glover, Emily A., 2019

Taylor, John D. & Glover, Emily A., 2019, Unloved, paraphyletic or misplaced: new genera and species of small to minute lucinid bivalves and their relationships (Bivalvia, Lucinidae), ZooKeys 899, pp. 109-140 : 109

Pusillolucina biritika sp. nov. Fig. 12

Type material.

Holotype: MNHN-IM-2000-35109 1.1 mm, Paratypes: MNHN-IM-2000-35110, MNHN-IM-2000-35111, MNHN-IM-2000-35181, NHMUK 20191084 lengths 1.1-1.5 mm.

Type locality.

Holotype: South Madagascar east of Cap Antsirabe, 49-52 m, ATIMO-VATAE stn TP11, 25°02.8'S, 47°01.3'E. 06MAY2010 (MNHN-IM-2000-35109).

Paratypes: South Madagascar east of Cap Antsirabe, 49-52 m, ATIMO-VATAE stn TP11, 25°02.8'S, 47°01.3'E. 06MAY2010 (MNHN-IM-2000-35181 5 v).

South Madagascar off Baie Fort-Dauphin 54-56 m, ATIMO-VATAE stn TP18, 25°02.4'S, 47°03.2.6'E, 11MAY2010 (MNHN-IM-2000-35110 6 sh, 9 v. NHMUK 20191084 1 sh, 2 v).

Northwest Madagascar, S of Cap St Sébastien, 42-44 m, MIRIKY stn DW3202, 12°35.6'S, 48°49.9'E, 29JUN2009 (MNHN-IM-2000-35111 6 v).

Etymology.

Biritika, meaning extremely small in Malagasy. Used as a noun in apposition.

Diagnosis.

Pusillolucina with posterior lateral teeth divided into three cusps and sockets.

Description.

Very small, L 1.5 mm, sub-ovate, longer than high, umbones prominent. Sculpture of fine commarginal lamellae crossed at anterior and posterior by low, rounded, radial ribs, juvenile shells with commarginal lamellae only. Some lamellae extended as scales along posterior dorsal margin. Lunule long, lanceolate. Ligament short internal on short resilifer. Hinge: RV with single cardinal tooth and single anterior lateral tooth, posterior lateral tooth short, divided into three cusps, LV with two cardinal teeth the posterior-most thin, posterior lateral tooth with three sockets for cusps of the right valve. Anterior adductor muscle scar short, barely detached from pallial line, posterior scar ovate. Pallial line entire. Shell margin coarsely crenulate, more strongly to anterior and posterior.

Figures

Figure 12. Pusillolucina biritika sp. nov. A, B South Madagascar east of Cap Antsirabe, 49 - 52 m, ATIMO-VATAE stn TP 11, 25 ° 02.8 ' S, 47 ° 01.3 ' E. (MNHN) C-E, L, M South Madagascar off Baie Fort-Dauphin 54 - 56 m, ATIMO-VATAE stn TP 18, 25 ° 02.45 ' S, 47 ° 03.26 ' E (MNHN) F-K Northwest Madagascar, S of Cap St Sebastien, 42 - 44 m, MIRIKY stn DW 3202, 12 ° 35.6 ' S, 48 ° 49.9 ' E (MNHN). A Holotype, stn TP 11 (MNHN-IM- 2000 - 35109), L 1.1 mm B paratype stn TP 11 (MNHN-IM- 2000 - 35181) L 1.5 mm C paratype stn TP 18 (MNHN-IM- 2000 - 35110) exterior of left valve, L 1.3 mm D paratype stn TP 18 (MNHN-IM- 2000 - 35110) interior of right valve, L 1.3 mm E paratype stn TP 18 (MNHN-IM- 2000 - 35110) exterior of left valve L 1.5 mm F paratype stn DW 3202 (MNHN-IM- 2000 - 35111). exterior of right valve L 1.4 mm G paratype stn DW 3202 (MNHN-IM- 2000 - 35111). exterior of right valve L 1.1 mm H paratype stn DW 3202 (MNHN-IM- 2000 - 35111) interior of left valve L 1.4 mm I paratype stn DW 3202 (MNHN-IM- 2000 - 35111) interior of right valve L 1.3 mm J, K detail of hinge teeth of H and I. L, M Paratype TP 18 (MNHN-IM- 2000 - 35110) exterior of left valve and interior of right valve L 1.2 mm.