Dilocarcinus septemdentatus ( Herbst, 1783 )

Collins, Pablo A., Giri, Federico & Williner, Verónica, 2009, Range extension for three species of South American freshwater crabs (Crustacea: Decapoda: Trichodactylidae), Zootaxa 1977, pp. 49-54 : 50

Dilocarcinus septemdentatus ( Herbst, 1783)

( Fig. 1 a)

Dilocarcinus septemdentatus — Magalhães 2003: 206 p., fig. 109.

Diagnosis. Carapace: 6 distinctive teeth on each anterolateral border. Abdominal segments III–VI of males fused. Third abdominal segment with slight, smooth margin, without the distinction of a crest among the others abdominal segments. Male pleopod (plp 1) gently curving outwards, distal end extending beyond subterminal spine field, as long as spine field ( Fig. 1 a).

Habitat. This species was observed within aquatic vegetation, mainly Eicchornia crassipes, along with other crabs such as D. pagei , Trichodactylus borellianus .

Material examined. Nine males and three females, carapace width 22.5 mm (SD 8.69 mm), FANM N° MFA - ZI 347, Salado River) ( Argentina, Santa Fe, Santo Tomé, 31°39'S 60°45'W), without collection date, Collins coll.; two males and one female, FANM N° MFA - ZI 402, Colastiné River ( Argentina, Santa Fe, Colastiné Sur, 31°37'S 60°34'W), 8.9.63, Martinez; one male, ML-INALI N° B 7, San Javier River ( Argentina, Santa Fe, 29°13’S 59°35’W), 30.11.0 5, Collins coll.; one male, ML-INALI N° B 8, Setúbal lagoon ( Argentina, Santa Fe, Rincón, 31°35'S 60°39'W), 1.12.0 5, Collins coll.; one male, ML-INALI N° B 16, Los Amores stream ( Argentina, Santa Fe, 28°51’S 59°29’W), 29.11.0 5, Collins coll.; two males and two females ML-INALI N° B 21, Parque del Sur lake ( Argentina, Santa Fe, Santa Fe city, 31°39'S 60°42'W), 28.11.0 6, Collins.

Southern locations. Setúbal Lagoon (31°35'S 60°39'W), Colastiné River (31°37'S 60°34'W), Parque del Sur Lake (Santa Fe city) (31°39'S 60°42'W) and Salado River (31°39'S 60°45'W), Paraná River floodplain, Argentina.

New distribution. Paraguay, Brazil and Argentina, Salado River as southern limit (31°39’S, 60°45’W) ( Fig. 2 a).

Figures

FIGURE 1. Right male pleopod 1, mesial aspect of A) Dilocarcinus septemdentatus, together with ventral view of the carapace with the abdominal segments (A’), B) Sylviocarcinus pictus, and C) S. australis, all from specimens from the Paraná River, Argentina. Scale bar equals 1.0 mm.

FIGURE 2. Distribution maps of Dilocarcinus septemdentatus, Sylviocarcinus pictus and S. australis according to Magalhães and Türkay (1996 a; b); Magalhães (1998; 1999 a; b; 2000); Morrone and Lopretto (2001). Dots, locations; drawn lines, distribution known to date; brown lines, newly reported distribution areas.