MOLECULAR AND MORPHOMETRIC EVIDENCE FOR SEPARATE SPECIES OFUNCINARIA(NEMATODA: ANCYLOSTOMATIDAE) IN CALIFORNIA SEA LIONS AND NORTHERN FUR SEALS: HYPOTHESIS TESTING SUPPLANTS VERIFICATION

摘要: California sea lions (Zalophus californianus) and northern fur seals (Callorhinus ursinus) are each believed to host distinct hookworm species (Uncinaria spp.). However, a recent morphometric analysis suggested that single parasitizes multiple pinniped hosts, the observed differences host-induced. To explore systematics of these hookworms test competing hypotheses, we obtained nucleotide sequences nuclear ribosomal DNA (D2/D3 28S, D18/D19 internal transcribed spacer [ITS] regions) from 20 individual parasitizing lion seal pups where their breeding grounds sympatric. Five individuals an allopatric population were also sampled for ITS-1 28S sequences. The D2/D3 showed no diagnostic among seals, whereas had one derived (apomorphic) character demarcating seals. ITS variable 7 characters, with 4 states in lions. Multivariate data revealed significant between nematodes representing 2 host-associated lineages. These results indicate represent not distributed indiscriminately species, but instead exhibit fidelity, evolving independently respective species. This evolutionary approach analyzing sequence delimitation is contrasted similarity-based methods have been applied numerous studies nematode parasites.