Small, rare and little known: new records and species of Cardiomya (Bivalvia: Cuspidariidae) from Brazil Author Lima, Tarcilla Carvalho De 7FFCF3E3-A9BF-469F-964A-62C618DE5192 Universidade Federal do Rio de Janeiro, Instituto de Biologia, Laboratório de Malacologia. C. E. P. tarcillacarvalho@gmail.com Author Oliveira, Cléo Dilnei de Castro 4BE74DFD-DD38-4315-A461-1E05F9706642 Universidade Federal do Rio de Janeiro, Instituto de Biologia, Laboratório de Malacologia. C. E. P. cleo.oliveira@gmail.com Author Absalão, Ricardo Silva D89BFB87-8BAF-44C4-AABD-5A40E202EE4C Universidade Federal do Rio de Janeiro, Instituto de Biologia, Laboratório de Malacologia. C. E. P. absalao@hotmail.com text European Journal of Taxonomy 2020 2020-03-26 619 1 20 journal article 22460 10.5852/ejt.2020.619 5dc6e760-5dcb-4928-a58e-c88c8524b8f9 3777241 BBB01195-73A4-44DB-8454-CC86B9C21EDF Cardiomya minerva sp. nov. urn:lsid:zoobank.org:act: B7AF183B-CE39-4084-A9B1-E0F366458513 Fig. 5 A–F Diagnosis Quadrangular shell flank, very short truncated rostrum, posterodorsal margin curved upwards, extending above the umbones; external sculpture composed of six posterior radial ribs, rostrum with commarginal growth lines only. Etymology This species is named after the character Minerva McGonagall, from the Harry Potter series of books written by the British J.K. Rowling. The name is employed as a noun in apposition. Material examined Holotype BRAZIL – Alagoas state • [ 1i ]; Maceió, Praia da Avenida ; 10 m depth ; 10 Apr. 1990 ; IBUFRJ 5785 . Other type material PORTUGAL • [ 12v and fragments], syntypes of Cardiomya cadiziana Huber , 2010 [= replacement name for Cardiomya curta (Jeffreys, 1876) ]; off Algarve ; 36°54′00″ N , 8°14′30″ W ; 523–684 m depth; USNM 172032 • [ 5v ], syntypes of Cardiomya cadiziana ; São Pedro Canyon ; 39°55′00″ N , 9°56′00″ W ; 1818 m depth; USNM 172033 • [ 4v ], syntypes of Cardiomya cadiziana ; São Pedro Canyon ; 39°42′00″ N , 9°43′00″ W ; 1097–2003 m depth; USNM 172034 . SURINAME • [ 1v ], holotype of Cardiomya surinamensis van Regteren Altena, 1971 ; 06°22.5′ N , 55°10′ W ; 20 m depth ; RMNH.MOL.55387 . Description Shell small (length 4.3 mm ; height 3.2 mm ). Shell flank quadrangular, umbones raised. Anterodorsal margin forming a shoulder, anterior and ventral and margin rounded, little angulated. Rostrum very short, truncated, posteroventral sinuation shallow, posterodorsal margin curved upwards, extending Fig. 5. A–F. Cardiomya minerva sp. nov. , holotype (IBUFRJ 5785). A–B . External view, left and right valve. C–D . Details of the posterior radial ribs and the rostrum. E–F . Hinge detail. — G–H . Cardiomya surinamensis van Regteren Altena, 1971 , holotype (RMNH.MOL.55387), left valve. G . External view. H . Hinge detail. — I–J . Cardiomya cadiziana Huber, 2010 , syntype (USNM 172032), left valve. I . External view. J . Hinge detail. Scale bars: A–B, G–J = 1 mm; C–D = 0.25 mm; E–F = 0.5 mm. above the umbones. External sculpture of six radial ribs on the posterior half of the shell flank; rostrum with commarginal growth lines only. Geographic distribution Only known from the type locality. Remarks The most similar species to Cardiomya minerva sp. nov. are Cardiomya surinamensis van Regteren Altena, 1971 ( Fig. 5 G–H) and Cardiomya cadiziana Huber, 2010 ( Fig. 5 I–J). These two species can be distinguished from Cardiomya minerva sp. nov. by their trapezoidal shell flank, external sculpture composed of incomplete radial ribs on anterior region of the shell flank. Additionally, C . cadiziana exhibits a shorter rostrum, with several faint radial lines, and straight posterodorsal margin, not extending above the umbones.