Fredius platyacanthus

Magalhães, Francinéia Zanetti Patrícia Macedo de Castro Célio, 2018, Freshwater crabs (Decapoda: Brachyura: Pseudothelphusidae, Trichodactylidae) from the state of Roraima, Brazil: species composition, distribution and new records, Nauplius (e 2018011) 26, pp. 1-19 : 7-10

Fredius platyacanthus

Rodriguez and Pereira, 1992

( Figs. 1E, F , 3 )

Previous records. Magalhães and Pereira (2007: 124, tab. 4 - listed under Negro River basin); Magalhães et al. (2014: 104, in table, 105).

Distribution. Venezuela, Brazil (Amazonas, Roraima) ( Rodriguez and Pereira, 1992; Magalhães et al., 2014; this study).

Material examined. BRAZIL, Roraima: 1 male (51.8:31.7), MIRR 43 , mun. Amajarí [03°39’20”N 061°25’16”W], serra Tepequém, igarapé da Base, 01.v.2009, L.F. R . Guterres et al .; 1 male (39.6:24.8), MIRR 96 , mun. Amajarí [03°39’20”N 061°25’16”W], serra Tepequém, igarapé da Base, 24.ii.2011, leg. F. Zanetti, A.A. Otaviano, A.S. Sales and D. Teixeira ; 1 male (34.7:21.5), 1 female (47.0:29.0), MIRR 76 , mun. Amajarí [03°39’20”N 061°25’16”W], igarapé Meio, 07.iv.2010, leg. R . Serafim and J.G.L. Neto ; 1 male, MIRR 31 , mun. Amajari , serra Tepequém, SESC Ecological Station , 03°27’N 061°41’W, 25.viii.2008, L.F. R . Guterres , G. R . S. Abreu and I.M.M.C. Oliveira ; 1 male (36.6:23.1), MIRR 42 , mun. Amajarí , serra Tepequém, SESC Ecological Station , 03°27’N 061°41’W, 01.v.2009, leg. L.F. R . Guterres, P.M. Castro, F.C. Zanetti and J. Tavares; 1 ad. male (45.9:28.2), 4 immat. males, 1 female (24.1:15.2), MIRR 66 , mun. Amajarí , serra Tepequém, SESC Ecological Station , 03°27’N 061°41’W, 30.x.2009, R . Denner and P.M. Castro ; 2 males, MIRR 37 , mun. Alto Alegre, Yanomami Indigenous Reserve, comunidade Koreaup , Surucucu , igarapé Inajá , 03°02’N 064°07’W, 8.iv.2009, A.C. R . Vieira ; 1 male (99.4:62.1), 2 females (95.6:61.5; 102.1:63.4), INPA841 , Yanomami Indigenous Reserve, upper rio Mucajaí basin, Community Paapiú , unnamed stream, 02°39’61”N 063°09’31”W, 28.iv.1994, L.S. Aquino and U.C. Barbosa ; 1male (97.4:60.1,damaged), INPA 842 ; 1 male, 1 female, IVIC 1097 ; 1 male (78.2:48.3), MZUSP 13901 ; 1 male, MZUSP 13902 , mun. Alto Alegre, Yanomami Indigenous Reserve, rio Parima basin (trib. of rio Uraricoera ), rio Kanaakiú , PIN Xitei / Xidea , 02°36’29”N 063°52’18”W, 780 m elev., 03.vii.1995, V . Py-Daniel et al .; 1 male (54.1:33.1), INPA 840 , mun. Alto Alegre, Yanomami Indigenous Reserve, rio Parima basin (trib. of rio Uraricoera ), igarapé das Irmãs, cachoeira Grande, PIN Xitei / Xidea , 02°36’24”N 063°52’17”W, 750 m elev., 24.vi.1997, V . Py-Daniel et al .; 1 male (32.1:21.4), INPA 1337 ; 1 male (69.8:44.3), 2 females (92.1:57.6; 100.7:63.3), INPA 1329 , mun. Alto Alegre, rio Uxua-ú , PIN Homoxi , 02°29’51”N 063°43’47”W, 15.xi.2003, U. Barbosa .

Remarks. The G1s of the specimens studied herein ( Fig. 1E, F ) have the mesial process wide, with proximal margin distinctly convex in mesio-caudal view, and ending in a bifid tip; cephalic lobe auricular in latero-cephalic view, auxiliary lobe slightly shorter than cephalic one, with caudal border bearing small cephalic spine; field of apical spine well developed, wide, longitudinally situated along the latero-cephalic side. These features highly resemble those of the G1 of the holotype of F. platyacanthus that was figured by Rodriguez and Pereira (1992: 305, fig. 3), but some variations can be noticed: the cephalic lobe is a little shorter than the mesial process in the Roraima specimens (even considering the angle from which the illustration was made), and the cephalic spine is a bit smaller than that of the holotype.

Fredius platyacanthus was only known from the male holotype collected in the Icabaru River, a left bank tributary of the upper Caroni River, in the Orinocoan slopes of the Serra Pacaraima. The several records presented above indicate that the species is more widely distributed on the Amazonian slopes of the Guyana Shield. In addition to the records the from the upper and middle course of the Uraricoera River ( Fig. 3 ), Magalhães et al. (2006) recorded the species from the Yanomami village of Balawa-ú, in the state of Amazonas, Brazil, in the headwaters of the Demini River, a left tributary of the Negro River (the authors erroneously noted it as Fredius reflexifrons (Ortmann, 1897) in tab. 1).

At the moment, we prefer to consider our material as co-specific with the F. platyacanthus ’ type, since a more precise assessment of the variability of these G1’s features is not possible without examining a more abundant series of specimens from the upper Caroni River area.

Figures

Figure 1. Male first gonopod, left side, distal part, of the pseudothelphusid crabs from Roraima. A, Fredius beccarii (Coifmann, 1939), mesio-caudalview,INPA 1895; B,Fredius estevisi(Rodríguez, 1966), mesio-caudal view,INPA 839; C, F.estevisi, latero-caudal view, INPA 839; D, Fredius fittkaui (Bott, 1967), mesial view, INPA 1338; E, Fredius platyacanthus Rodriguez and Pereira, 1992, mesial view, INPA 840; F, F. platyacanthus, lateral view, INPA 840; G, Fredius stenolobus Rodríguez and Suárez, 1994, mesio-caudal view, INPA 1252; H, Kingsleya latifrons (Randall, 1840), mesio-caudal view, INPA 1248.

Figure 3. Distribution of the pseudothelphusid species, Fredius beccarii (Coifmann, 1939) (triangle), F.estevisi (Rodríguez, 1966) (star), and F. platyacanthus Rodriguez and Pereira, 1992 (circle), in the state of Roraima, Brazil.