Trizocarcinus dentatus ( Rathbun, 1893 )

CASTRO, PETER & NG, PETER K. L., 2010, Revision of the family Euryplacidae Stimpson, 1871 (Crustacea: Decapoda: Brachyura: Goneplacoidea), Zootaxa 2375 (1), pp. 1-130 : 110

Trizocarcinus dentatus ( Rathbun, 1893)

( Figs. 44A–G ; 46A–F )

Carcinoplax dentatus Rathbun, 1893: 243 [Gulf of California].

Trizocarcinus dentatus Rathbun 1914a: 118 , fig. 1, pl. 1; 1918: 18, fig. 3, pl. 1 [Gulf of California]. — Garth 1948: 52 [ Ecuador]; 1960: 113. — Guinot 1969b: 518 [discussion], figs. 37, 44, 46, 48, 49 [holotype]; 1971: 1081 [in list]. — Chirichigno 1970: 61, fig. 151. — del Solar 1970: 44 [ Perú]. — del Solar et al. 1970: 27 [ Perú]. — Hendrickx 1990: 49 [Gulf of California]; 1992: 9 [in list]; 1993a: 314 [in list]; 1995: 139 [in list] [Pacific coast of Mexico]. — Lemaitre & Álvarez-León 1992: 56 [in list]. — Ng et al. 2008: 78 [in list].

Type material. Male holotype ( USNM 17462 ); 1 male paratype ( USNM 123310 ) .

Type locality. Mexico, Gulf of California, Sonora, off Cabo Lobos , 54–137 m.

Material examined. Mexico. Bahía de San Ignacio , Gulf of California, 30.03.1980: 1 male, 14.7 mm × 20.2 mm ( MNHN-B20990 ) . – Gulf of California , Albatross, stn. 3017, 29°54.5’N, 113°01.0’W, 104 m, 24.03, 1889: 1 pre-adult female, 10.0 mm × 12.4 mm ( USNM 17463 ) ; stn. 3035, 1 pre-adult female, 7.3 mm × 8.7 mm ( USNM 17464 ) . – Roca Consag , Gulf of California, 31°7’N, 114°29’W 09.05.1982: 1 male, 15.3 mm × 20.3 mm ( MNHN-B20987 ) .

Diagnosis. Dorsal, ventral surface of carapace granular ( Fig. 44B, C, F, G ). Granular stridulating ridge on pterygostomian region ( Rathbun 1918: fig. 3). G1 apex exceptionally long ( Fig. 46E ).

Remarks. Trizocarcinus dentatus , which is restricted to the Tropical Eastern Pacific region, shares with the Western Atlantic T. tacitus Chace, 1940 , a carapace with curved anterolateral borders each armed with two teeth ( Figs. 44A ; 45A ) as well as the other characters that define the genus Trizocarcinus . Its carapace, however, is granular in contrast to the smooth carapace of T. tacitus . The conspicuous, granular stridulating ridge along the pterygostomian region of T. dentatus ( Rathbun 1918: fig. 3) is absent in T. tacitus , and the cheliped tomentum ( Fig. 44D ) is generally more conspicuous than that of T. tacitus .

Distribution. Tropical Eastern Pacific region from the Gulf of California to northern Perú. Depth: 36– 126 m.

Figures

FIGURE 44. Trizocarcinus dentatus (Rathbun, 1893); male (14.7 mm × 20.2 mm) (MNHN-B20990), Mexico, Gulf of California. A, overall view; B, frontal view showing orbits and antennae; C, third maxillipeds; D, outer surface of right chelae; E, anterior portion of male thoracic sternum and abdomen; F, posterior portion of male thoracic sternum and abdomen; G, male sterno-abdominal cavity, G1, and penis. Abbreviations: a1–a3 = male abdominal somites 1, 2, 3, respectively; cx5 = coxa of fifth pereopod (P5); es7 = episternite 7; G1 = first male pleopod; mg = median groove; p = penis; s6–s8 = thoracic sternites 6 to 8, respectively.

FIGURE 45. Trizocarcinus tacitus Chace, 1940; female (20.6 mm × 29.4 mm) (MNHN-B30602), West Indies, Guadeloupe. A, overall view; B, female thoracic sternum and vulvae. Abbreviations: mg = median groove; md = median depression; s4–s7 = thoracic sternites 4 to 7, respectively; v = vulva.

FIGURE 46. A–F, Trizocarcinus dentatus, (Rathbun, 1893) (after Guinot 1969b: figs. 37, 44, 46, 48, 49); G–M, Trizocarcinus tacitus Chace, 1940 (after Guinot 1969b: figs. 34, 43, 45, 50a, 50b, 51). A, G, frontal view showing orbits and third maxillipeds; B, H, posterior portion of male thoracic sternum, abdomen, and gonopore; C, I, anterior portion of male thoracic sternum and abdomen; D, J, posterior portion of male thoracic sternum and abdomen; E, K, L, G1; F, M, G2. Abbreviation: a2, a3 = male abdominal somites 2 and 3, respectively; g = gonopore.