Argonauta nodosus (Cephalopoda: Argonautidae) in Patagonian Waters

VALES DAMIÁN GUILLERMO; HERNÁNDEZ-ORTS, JESÚS S.; DURANTE, CRISTIAN; SOSA DROUVILLE, AILIN; GARCÍA NÉSTOR ANÍBAL; CRESPO ENRIQUE ALBERTO; ORTIZ, NICOLAS

MALACOLOGIA

INST MALACOL

Año: 2019 vol. 62 p. 367 - 371

0076-2997

Four empty shells of female argonauts werefound on the shores of the marine protectedarea Parque Interjurisdiccional Marino CosteroPatagonia Austral (PIMCPA) on the northerncoast of the San Jorge Gulf, Chubut province,Argentina. The first specimenwas found May 1, 2016, near Punta Castillosand is deposited in the Colección de Invertebrados(CNP-INV), CCT CONICET?CENPAT,Puerto Madryn, Chubut, Argentina. The other three shellswere found by PIMCPA staff on May 29, 2016, in BahíaHuevo and are housed in the Intendancy ofthe PIMCPA, Camarones, Chubut province,Argentina.Specimens were identified as A. nodosusbased on the presence of tubercles in lateralribs, a keel of increasing width, and tubercles onkeel alternate rather than opossed. Shelllength ranged from 104.1 to 127.3 mm and shellbreadth from 69.4 to 83.7 mm.Argonauta nodosus has a circum-globaldistribution in the Southern Hemisphere,between 10°S and 44°S, whereas the 38°37?S is the southern-mostrecord for the species in the western SouthAtlantic Ocean. As argonaut shells are not expected to float or driftfar at sea when separated from the animals,shell records can be used to document theirgeographical distributions. Thepresent record from Patagonia thus expandsthe southern-most distribution of A. nodosusin the western South Atlantic Ocean by near6.5° of latitude (from 38°37?S to 45°S); hence the worldwide distribution becomesmore southerly by 1° of latitude. Nevertheless,the occurrence of argonauts in the Patagonianwaters can be regarded as atypical.