Corynosoma australe Johnston, 1937 and C. cetaceum Johnston & Best, 1942 (Acanthocephala: Polymorphidae) from marine mammals and fish in Argentinean waters: genetic differentiation and taxonomic status.

SARDELLA, N.H.; MATTIUCCI, S.; TIMI, J.T.; BASTIDA, R. ; RODRIGUEZ, D.; NASCETTI, G.

SYSTEMATIC PARASITOLOGY

Springer Netherlands

Lugar: Amsterdam; Año: 2005 vol. 61 p. 143 - 156

0165-5752

Genetic and morphological studies were performed on acanthocephalans, belonging to the genus Corynosoma Lühe, 1904, referable to the species Corynosoma cetaceum Johnston & Best, 1942 and C. australe Johnston, 1937 recovered from definitive and intermediate hosts from Argentinian waters, with the aims to estimate the level of genetic differentiation between the two taxa at any stage of their life-cycle, to provide genetic (allozyme) markers for their recognition and to analyze the systematic status of both taxa. Acanthocephalans were collected from the stomach and intestine of Arctocephalus australis (Zimmerman), intestine of Mirounga leonina (Linnaeus) and stomach of Pontoporia blainvillei Gervais & D´Orbigny (definitive hosts) from Argentinian waters. Alternative alleles at all the 13 enzymatic loci studied were observed between C. australe and C. cetaceum. The specimens from the stomach of both P. blainvillei and A. australis were identified, on the basis of the high number of diagnostic loci found, as C. cetaceum>; those from intestine of both A. australis and M. leonina as C. australe. A high genetic differentiation (DNei=¥; INei=0.00) between the two taxa was found, suggesting a generic distinction between the two species. Cystacanths of the two species from body cavity of the fish Cynoscion guatucupa (Cuvier) collected from the same geographic area were genetically identified. Morphological patterns such as the number of hooks and hook rows of proboscis, distribution of somatic and genital armature and other morphometric and meristic differences as well as ecological data, allowed to identify two species, C. australe and C. cetaceum, at cystacanth, juvenile and adult stages. However a number of morphologic and morphometric features of Argentine acanthocephalans was different to those of C. australe and C. cetaceum described from other regions of the world.