Living and Fossil Darwinulidae (Ostracoda, Crustacea) from Argentina

BALLENT, SARA.; DÍAZ A.R.

Brasilia, Brasil

Simposio; XVI ISO (International Symposium Ostracoda); 2009

IRGO

Recent, Holocene and Mesozoic records of darwinulid ostracods belonging to the genus Penthesilenula Rossetti and Martens (incae-group) have been reported in several areas in Argentina. Living species have been recognized in temporary ponds along the National Route 11 (27º48? S, 59º16?W, Chaco Province) and in the water entrapped in the leaf cups of Eryngium cf. pandanifolium (Apiaceae) at National Park of Iguazú, Misiones Province, both of which are currently under study. Penthesilenula incae (Delachaux) has been recognized in small swamps near a stream (Arroyo Telsen, Chubut Province, 42º14?S, 67º04?W). Holocene records of P. incae are from lacustrine sediments at Quebrada de Zonda, San Juan Province (approx. 32ºS-70ºW) and in estuarine sediments from southern Buenos Aires Province (38º34?S, 58º42?W). Jurassic records come from lacustrine sediments of different localities in Patagonia. The first of them comes from limestones, calcareous sandstones and volcanic tuffs of the Callovian-Oxfordian Cañadón Asfalto Formation in the middle Chubut river valley (between 42º36?- 44º00? S and 70º00?-68º30W); the second one, found in olive grey and greenish  brown claystones (Piedra Pintada Formation) of late Pliensbachian age, is from the eastern slope of Cerro Corona (40º10´S, 70º21´W) in Neuquén Province. The last one was recovered from a drilling core sample in the southern Mendoza Province (between 37º00?-37º20?S and 69º00?-69º30?W) of early Jurassic age. These records enlarge the geographical distribution of the genus which is restricted to the southern Hemisphere. To our knowledge, the Argentinian Jurassic records constitute the oldest known for the genus.