Mactrotoma fragilis ( Gmelin, 1791 )

Signorelli, Javier H. & Pastorino, Guido, 2012, Taxonomic revision of Brazilian Mactridae Lamarck, 1809 (Bivalvia: Cardiida), Zootaxa 3245, pp. 30-53 : 38-42

Mactrotoma fragilis ( Gmelin, 1791)

Figures 6 A–K, 7A–E

Mactra fragilis Chemnitz, 1782: 236 , pl. 24, fig. 235 (rejected by ICZN, 1944, Opinion 184); Gmelin, 1791: 3261; Spengler 1802: 124; Wood, 1818: 30; Turton, 1822: 74, pl. 4, fig. 10; Conrad, 1831: 61, pl. 14, fig. 3; De Kay, 1843: 230; d’Orbigny, 1846 in 1834–1847: 508; 1853: 222; Forbes & Hanley, 1853: 368; Reeve, 1854: pl. 11, fig.47; Wood & Hanley, 1856: 39, fig. 32; Carpenter, 1855, in Carpenter, 1855 –57: 51; Martinez y Saez, 1869: 12; Mörch, 1870: 124; Weinkauff, 1884: 17, pl. 5, fig. 2; Dall, 1895: 211; 1894: 26; Lamy, 1917: 246; Maury, 1920: 131; Perry, 1940: 82, pl. 17, fig. 113; Abbott, 1954: 488, fig. 5587; Cauquoin, 1967: 223; Rios, 1970: 195; 1975: 236, pl. 75, fig. 1129; 1985: 243, pl. 86, fig. 1210; 1994: 265, pl. 90, fig. 1292, 2009: 535, fig. 1486; Altena, 1971: 52.

Lutraria candida Lamarck, 1818 in 1815–1822: 470; Deshayes & Milne-Edwards, 1835: 92; Hanley, 1842 in 1842 – 1856: 27; Lamy, 1913: 346.

Mactra braziliana Lamarck, 1818 in 1815–1822: 478— Deshayes & Milne-Edwards, 1835: 106; Beau, 1853: 414; Hanley, 1842 in 1842– 1856: 31, pl. 10, fig. 60; Conrad, 1868, 45; Gundlach, 1883b: 482; Dall, 1894b: 26; Lamy, 1914: 243.

Mactra oblonga Say, 1822: 310 — Conrad, 1868, 45; Dall, 1894b: 26.

Mactra oblongata [error pro oblonga] Ravenel, 1834: 2.

Spisula fragilis Gray, 1837: 373 ; Conrad, 1868: 45.

Mactra bilineata Reeve, 1854 : pl. 15, fig. 72— Deshayes, 1855a: 67; Weinkauff, 1884: 84, pl. 28, figs. 6–6a; Tomlin, 1924: 136.

Standella bilineata H. Adams & A. Adams, 1856 in 1853–1858: 382— Dall, 1894b: 26.

Standella fragilis H. Adams & A. Adams, 1856 in 1853–1858: 382; Conrad, 1868: 45.

Spisula (Standella) bilineata ( Reeve, 1854) — Conrad, 1868: 44.

Mactra anserina Guppy, 1875: 49 , pl. 7, fig.1— Dall, 1894b: 26.

Diagnosis. Shell trigonal to oval, pallial sinus rounded and deep of about half shell length, maximum length measured 85 mm (ANSP 338354); left hinge with anterior lateral teeth with two cusps, right hinge with anterior ventral lateral teeth with two cusps.

Description. Shell trigonal to oval, inequilateral, external surface smooth without ornamentation ( Fig. 6 D), posterodorsal area defined by a line from umbones to posterior end and covered by a brownish periostracum; anterior end rounded, lunule not defined; ventral margin convex; internally white, right hinge with two anterior and two posterior lateral teeth, the ventral anterior with two cusps, the posterior similar in size and with one cusp; two cardinal teeth (3a & 3b) unfused ( Fig. 7 A); left hinge with V-shaped cardinal tooth composed of two single cardinals (2a & 2b), one anterior and one posterior lateral tooth (AII & PII), the anterior with two cusps ( Fig. 7 B). Ultrastructure of the shell with two layers as in other species here studied ( Figs. 7 C–E).

Type material. [ Mactra fragilis ] types not found at ZMUC, ZMB and Zoological Institute of Russian Academy of Science of St. Petersburg ( Martynov 2002), probably lost; [ Lutraria candida ] MNHN unnumbered, two syntypes; [ Mactra braziliana ] MNHN unnumbered, one syntype; [ Mactra oblonga ] ANSP 51418 , one syntype; [ Mactra bilineata ] NHMUK unnumbered, two syntypes; [ Mactra anserina ] types not found at NHMUK, Guppy main collection deposited at Victoria Institute, Trinidad, destroyed by fire in 1920 ( Sherborn 1940).

Type locality. Nicobar Islands, India, erroneously recorded.

Other material examined. United States of America—Myrtle Beach, North Carolina ( USNM 471502 , 487435) ; South Carolina ( USNM 27020 ; ANSP 51417 , 51419, 51418, 178514; AMNH 292619 , 270166) ; Beaufort, South Carolina ( MNRJ 1289 ; USNM 27015 , 462356, 426251, 126104; USNM 54361 ) ; Florida ( FURG 3106 ; USNM 54351 , 124262, 604795; ANSP 43998 , 175870, 132403, 186630, 51420, 76091, 174710, 158565, 189774, 174685, 180440, 387126, 88241, 76656, 354086, 264033; AMNH 210012 , 311038, 139098, 131872, 121162, 125638, 100385, 248021, 172235, 248026; MZUSP 36139 , 46840, 62656, 62663) ; Cape Canaveral ( ANSP 371472 ) ; Peanut Island ( AMNH 293566 ) ; Prickly Bay, Florida ( ANSP 296550 ) ; Lake Worth, Florida ( USNM 253194 , 127259, 127259, 599286) ; Miami, Florida ( AMNH 140442 , 36058) ; Biscayne Bay, Florida ( AMNH 120144 ) ; Caesars Creek bank ( USNM 462364 ) ; Honda Bay, Florida ( AMNH 309253 ) ; Sanibel ( ANSP 175433 , 170554; AMNH 309260 , 120142, 103342, 100035, 97438, 99887) ; Lemon Bay ( USNM 732875 , 741380) ; Sarasota Beach, Florida ( USNM 533964 ) ; Sarasota Bay, Florida ( AMNH 120143 ); Bird Key, Tortugas ( USNM 426252 , 27016, 462357); Manatee River ( USNM 61076 , 604755); Bradenton Beach, Florida ( AMNH 199586 ); St. Petersburg. Florida ( AMNH 248820 ; 172236); Egmont Key, Florida ( USNM 117656 ); Tampa Bay ( USNM 27014 , 462361); Cedar Key ( USNM 36039 , 134863, 93660); Dog Island, Apalachicola ( USNM 185476 ); West Florida ( ANSP 193681 ); Saint Augustine, Florida ( USNM 61158 ); St. Andrews Bay, Florida ( AMNH 266831 ; 266832); Texas ( USNM 125653 ; ANSP 161372 , 180061, 176590, 348776, 401045; AMNH 293567 ; MZUSP 13033 ); North of Mississippi ( ANSP 209694 ); Palisades ( USNM 442511 ); Old Providence ( ANSP 154635 ); Dickinson Bay, Texas ( ANSP 394662 ); Matagorda Bay, Texas ( USNM 106996 , 134410, 465242, 107376); Rockport, Texas ( USNM 134411 ); Corpus Christi, Texas ( USNM 123487 ). Central America—Gulf of Mexico ( ANSP 338354 ); San Carlos Bay, Mexico ( AMNH 131189 ); Yucatán ( USNM 27017 ); Hopkins, Belize ( ANSP 282762 , 282921); Belize ( USNM 777780 , 771015, 771028; AMNH 183702 ; ANSP 285014 , 282293, 284251, 284252); Honduras ( NHMUK 1963.33.1–4, 4 valves, 1 illustrated by Reeve (1854)); Venado, Panama ( AMNH 248509 ); Panama channel ( USNM 743472 ; 783033, 821599); Randolph, Panama ( USNM 759164 , 759346); Panama bay ( AMNH 159536 ); Bahamas ( AMNH 168779 ; USNM 707309 , USNM 846338 ; ANSP 375172 ; 375171); La Habana bay ( ANSP 52698 ); Cabañas Harbour, Cuba ( USNM 462366 ); Cárdenas Bay, Cuba ( USNM 462365 ); Cuba ( AMNH 113659 ); Santa Rosa, Cuba ( USNM 462360 ); Cienfuegos, Cuba ( USNM 462363 ; Jamaica ( USNM 440799 , 442762, 423771, 102894, 27018, 441315, 375542; AMNH 34065 , 34901); Haiti ( USNM 383300 , 440449, 440227); Dominican Republic ( AMNH 94720 ); Santa Bárbara de Samana ( MNRJ 1290 ); Santo Domingo ( ANSP 173309 , 182441); Talleboa, Puerto Rico ( AMNH 174 ); Virgin Islands ( AMNH 185921 , 185851); Saint Thomas ( USNM 530415 , 604811, 250119, 321646); Tortola ( ANSP 51415 ); Seaforth Bay, Antigua ( AMNH 311152 ); Saint George, Grenada ( ANSP 344048 , 332097; AMNH 185257 ); Icacos, Trinidad ( ANSP 157776 ). Colombia—Carta-gena ( USNM 517823 , 364328); Puerto Colombia ( USNM 543429 ). Venezuela—Margarita Island, ( USNM 786537 ; MZUSP 57369 , 58709, 61627); La Guaira ( ANSP 264261 ). Brazil—Pernambuco ( MZUSP 14805 ); Marau ( MZUSP 22391 ); Salvador ( MZUSP 28480 , 44241, 44980, 44982, 45005, 59291, 59292, 59301, 77465, 77466, 81200); Bahía ( MZUSP 15644 , 26828, 70207; FURG 22285 , 23467, 41374, 10814, 47433, 9945; ANSP 263476 ); Espírito Santo ( MZUSP 73065 ); Búzios ( MZUSP 48473 , 57127); Niterói ( MNRJ 4387 ); Muriqui ( MNRJ 1479 ); Mangaratiba ( MNRJ 5354 ); Rio de Janeiro ( MNRJ 2708 , 6610, USNM 17500 , 120193, AMNH 34064 , 34063; MACN-In 5022; MZUSP 22392 , 77464, 83188, 40122); Ilha Grande ( MZUSP 22316 ); Peruíbe ( MZUSP 80834 ); São Sebastião ( MZUSP 22398 , 22401, 22402, 44203, 44244, 44997, 56205; FURG 17158 ); Santos ( MZUSP 13042 ); São Paulo ( MZUSP 22400 , 59311, 81934); Ubatuba ( MZUSP 14944 , 22394, 26477); Bertioga ( MZUSP 50484 , 62147); Cananeia ( MZUSP 83348 , 83386); Ilha Bela ( MZUSP 22399 , 41683, 41712, 41785, 44971, 44996, 77463, 77467, 77468, 77469, 77470, 77579, 79935, 83468); Porto Belo ( FURG 11784 ); Bombinhas ( MZUSP 34588 ); Santa Catarina ( FURG 40237 , 1576, 47781; MZUSP 13041 ).

Distribution. From North Carolina, USA, to Santa Catarina, Brazil.

Remarks. Mactra fragilis was introduced by Chemnitz (1782). However, this work was rejected due to nomenclatorial causes (Direction 1 ICZN 1954, Opinion 184, 1944). Mactra fragilis ( Gmelin, 1791) , a common species living in the western Atlantic has been cited with other names, i.e.: Lutraria candida Lamarck, 1818 ( Figs. 6 B–C); Mactra braziliana Lamarck, 1818 ( Figs. 6 D–F); Mactra oblonga Say, 1822 ( Figs. 6 G–H); Mactra bilineata Reeve, 1854 ( Figs. 6 I–J) and Mactra anserina Guppy, 1875 ( Fig. 6 K) which are considered synonyms according to the similarities observed in the type material. Mactra oblonga was erroneously cited by Ravenel (1834) as M. oblongata (nomen nudum).

Mactra dealbata Pulteney, 1799 , later named as M. tellinoides Pulteney, 1813 , is a valid species that was erroneously considered a synonym of M. fragilis by Wood and Hanley (1856), Dall (1894b), Lamy (1917), among others. This species was mentioned living along the coast of Dorset, England. Mactra ambigua Weinkauff, 1884 , cited by Dall (1894b) as synonym of M. fragilis , is in fact a synonym of M. compressa Spengler, 1802 , living along the northern Atlantic coast of Africa. This conclusion was drawn after the revision of Spengler´s mactrid types deposited at ZMUC. Finally, Mactra ovalina Lamarck, 1818 , cited as synonym of M. fragilis by Carpenter (1855, in Carpenter, 1855 –57), Dall (1894b), and others, is a valid species living in Arabia ( Bosch et al. 1995).

Figures

FIGURE 6. Mactrotoma fragilis (Gmelin, 1791). A: original illustration of Chemnitz; B – C: Lutraria candida Lamarck, 1818, syntype (MNHN unnumbered), RV; D – F: Mactra braziliana, Lamarck, 1818, syntype (MNHN unnumbered), D: RV, E: LV; G – H: Mactra oblonga Say, 1822 syntype (ANSP 51418) LV and RV respectively; I – J: Mactra bilineata Deshayes in Reeve, 1854, Syntype, NHMUK unnumbered; K: Mactra anserina, original illustration of Guppy, 1875, scale bar = 1 cm.

FIGURE 7. Mactrotoma fragilis (Gmelin, 1791), A – B: hinge description by using the nomenclature developed by Bernard and Munier Chalmas, scale bar = 1 cm, A: RV, B: LV; C – E: Ultrastructure of the shell, C: general aspect of radial section of a LV from close to hinge to ventral margin scale bar = 100 µm, D: detail of the outer layer with cross lamella structure, scale bar = 50 µm, E: detail of inner layer with the cross lamellar complex, scale bar = 20 µm.