Volume 2, Issue 3, April 1997
Volume 2, Issue 3 – April 1997
Sazima, I., Rodrigo L. Moura and R. S. Rosa: Elacatinus figaro sp. n. (Perciformes: Gobiidae) a new cleaner goby from the coast of Brazil, pp. 33-38.
Elecantinus figaro n. sp., a cleaner goby of the horsti complex, is described from the coast of Brazil. The new species differs from its congeners of the horsti complex by the combination of the following characters: enlarged caninens lacking in females, pale dorso-lateral stripe (bright yellow in life) reaching the lateral septum, and pale median spot (bright yellow in life) on snout. This species represents the southern most record for a cleaner goby in the western South Atlantic.
Elacatinus figaro sp. n. among encrusting sponges on rocky bottom. Búzios, off Rio de Janeiro, southeastern Brazil. Photo by M. Colucci
Lasso, C. A., A. Rial B. and O. Lasso-Alcala: Notes on the biology of the freshwater stingrays Paratrygon aiereba (Muller & Henle, 1841) and Potamotrygon orbignyi (Castelnau, 1855) (Chondrichthyes: Potamotrygonidae) in the Venezuelan llanos, pp. 39-50.
The ontogenetic development, reproduction, feeding habits and habitats and habitat of the stingrays Paratrygon aiereba and Potamotrygon orbingyii from the Venezuelan Ilanos (Apure river basin) were studied. According to the ontogenetic development, four stages were considered. Fetuses, immatures, sexually maturing and mature individuals. The variation of 12 measurements and their development in relation to disk width are described. P. aiereba attained greater size (780 mm DW) and weight (25 kg) than P. orbignyi (325 mm DW) and weight (2 kg). In P. aiereba males, sexual maturity is apparently reached at a size larger than 410 mm DW, whereas in P. orbingyi sexual maturity is attained at 230 DW. Females show signs of sexual maturation at 370 and 185 mm DW in P. aiereba and P. orbignyi respectively. Pregnancy and littering in both species goes on all year. Births seem to be more frequent during the rainy season. According to our data, the litter size varies between one and two young in each reproductive cycle in both species. P. aieereba is a piscivore even though shrimps are important items in tis diet. P. orbignyi is essentially an insect feeder. P. aiereba has been observed obly in the main channel of the Caño Guaritico (clear water) whereas P. orbignyi is usually found in a wide range of habitats and water types.
Potamotrygon sp., Rio Araguaia, Aruaná, Brazil. Photo by H. Bleher