Loxoconcha (Loxocorniculum) tricornata ( Krutak, 1971 )

Antonietto, Lucas Silveira, Machado, Cláudia Pinto, Carmo, Dermeval Aparecido Do & Rosa, José Wilson Correa, 2012, Recent Ostracoda (Arthropoda, Crustacea) from São Pedro-São Paulo Archipelago, Brazil: a preliminary approach, Zootaxa 3335 (1), pp. 29-53 : 45-46

Loxoconcha (Loxocorniculum) tricornata ( Krutak, 1971)

Fig. 8 :4–17

1866 Normania dorsotuberculata var. Brady. Brady, p. 383 (parte), pl. 61, figs. 14e-g.

1866 [non] Normania dorsotuberculata var. Brady. Brady, p. 383 (parte), pl. 61, figs. 14a-c.

1963 Loxocorniculum fisheri (Brady) . Benson & Coleman II, p. 69 (parte 2), text-figs. 24a-c.

1963 [non] Loxocorniculum fischeri (Brady) . Benson & Coleman II, p. 39, pl. 7, figs. 3–4.

1971 Loxocorniculum tricornatum Krutak , p. 10, pl. 3, figs. 1a-c.

1975 Loxoconcha oculocrista Teeter. Teeter , p. 479, figs. 20d, 21 a-c.

1975 Loxoconcha suboculocrista Teeter. Teeter , p. 479, figs. 20b, 21d-f.

1979 Loxocorniculum tricornatum Krutak. Krutak & Rickles , p. 269, pl. 1, figs. 8–13, fig. 4.

1982 Loxocorniculum tricornatum Krutak. Krutak , p. 273, pl. 4, figs. 7–12.

?1983 Loxoconcha "grupo" postdorsoalata Puri. Palacios-Fest et al., l.4, figs. 1–2.

?1983 Loxoconcha suboculocrista Teeter. Palacios-Fest et al. , l.4, fig. 3.

1988 [non] Loxoconcha (Loxocorniculum) tricornata (Krutak) . Bold, p. 49, pl. 7, fig. 8.

1989 Loxocorniculum tricornatum Krutak. Machain-Castillo , pl. IV, fig. 14.4.

1992 Loxocorniculum tricornatum Krutak. Coimbra et al. , p. 96, pl. 1, fig. 5.

1993 Loxocorniculum visendum Witte. Witte , p. 60, pl. 8, figs. 11–15.

1999 Loxoconcha (Loxocorniculum) tricornata (Krutak) . Coimbra et al., p. 371, pl. 2, fig.9.

2000 Loxoconcha (Loxocorniculum) suboculocrista (Teeter) . Keyser & Schöning, p. 573, pl. 5, figs.83–87.

2000 Loxoconcha (Loxocorniculum) tricornata (Krutak) . Keyser & Schöning, p. 573, pl. 5, figs. 88–90.

2011 Loxoconcha (Loxocorniculum) tricornata (Krutak) . Coimbra et al., p. 126, fig. 5.2, I.

Holotype. HVH 9046 ( Krutak, 1971).

Type locality. Nº 4 station, Mandinga Lagoon, Mexico ( Krutak, 1971).

Material. 212 specimens (82 from MP-612, 125 from MP-747 and five from MP-748).

*- Lost.

Figured specimens. CP-455, CP-459, CP-461, CP-462 and CP-463 (carapaces); CP-456, CP-457, CP-458, CP-460 and CP-464 (valves) ( Tab. 13).

Geographic and stratigraphic distribution. West Indies ( Brady 1866); Florida Bay, United States; Eastern Gulf of Mexico, Mexico ( Benson & Coleman II 1963); Mandinga Lagoon, Veracruz, Mexico ( Krutak 1971); South Stann Creek and Tobacco Entrance, Belize ( Teeter, 1975); Veracruz and Antón-Lizardo reefs, Mexico ( Krutak & Rickles 1979; Krutak 1982); Southern Gulf of Mexico, 21º-18ºN and 91º-97ºW, Mexico ( Machain-Castillo 1989); Tamandaré Bay, Pernambuco State, Brazil ( Coimbra et al. 1992); Bakau beach, Gambia ( Witte 1993); equatorial shelf, southeast to the Amazon river delta, Brazil ( Coimbra et al. 1999); Rocas Atoll, Brazil ( Coimbra et al. 2011); Saint Peter-Paul Archipelago, Brazil; Recent.

Remarks. The authors agree with Bold (1988) about reclassification of Loxocorniculum as a subgenus of Loxoconcha , distinguished by the presence of a posterodorsal tubercle, moderate to strong reticulation in lateral view, substraight dorsal margin in both sexes and angulated anterior end, ornamented with two small ribs. Observed specimens differ from those in Krutak (1971) by the presence of an additional tubercular projection in the posteroventral portion. According to Bold (op. cit.), some morphophysiological characters, including formation of tubercles, can be influenced by even small environmental variation. Loxocorniculum visendum is considered a junior synonym of L. (L.) tricornata , due to similarities with specimens from Witte (1993). Dubious identifications in Palacios-Fest et al. (1983) stem from incomplete or absent illustration in the original works.

Figures

FIGURE 8. Ostracods from São Pedro-São Paulo Archipelago, Northeastern Brazil. 1–3. Xestoleberis? sp. 3, Adult carapace, CP-500. 1. Right view. 2. Left view. 3. Dorsal view. 4–17. Loxoconcha (Loxocorniculum) tricornata (Krutak, 1971). 4–6. Adult carapace, CP-455 (♂). 1. right view. 2. left view. 3. dorsal view. 7–9. Adult valve, CP-464 (♂). 7. left internal view. 8. Central muscle scar in detail. 9. Interpretation of the central muscle scar. 7. Adult carapace, CP-463 (♀), right view. 8. A-1 valve, CP- 456, right view. 9. A-2 valve, CP-457, right view. 10. A-3 valve, CP-458, right view. 11. A-4 carapace, CP-459, right view. 12. A-5 valve, CP-460, left view. 13. A-6 carapace, CP-461, right view. 14. A-7 carapace, CP-462, right view. Scale = 100 µm.