PHYLOGENETIC POSITION AND PHYLOGEOGRAPHIC ANALYSIS OF THE SQUAT LOBSTER Munida gregaria.

PÉREZ BARROS, PATRICIA; CALCAGNO, J A; LOVRICH, GA; CONFALONIERI, V.

Qingdao

Conferencia; 7th International Crustacean Congress; 2010

Members of the family Galatheidae are distributed in the 3 major ocean basins. Munida gregaria is distributed around southern South America, New Zealand and southern Australia. The southeastern and southwestern Pacific Ocean is connected by the Antarctic Circumpolar Current, however no records of Munida gregaria have been made from the subantarctic islands in between South America and Oceania. In the present study we used molecular markers to investigate the phylogenetic relationships of Munida gregaria with other species of the genus and of the family Galatheidae (16S and COI), and to study the distribution of its genetic variability along its geographic distribution (ND1). We performed parsimony and Bayesian analyses to reconstruct phylogenetic relationships between M. gregaria from southern South America and other 39 species of galatheids: 35 from the South West Pacific, one from the South West Atlantic, one from the North East Pacific and two from the South East Pacific. Both analyses revealed that M. gregaria forms a monophyletic clade with Cervimunida johni, Pleuroncodes monodon and Munida quadrispina, species that inhabit the eastern Pacific Ocean (west coast of America). Therefore, a phylogenetic analysis including the other species of Pleuroncodes and Cervimunida will be necessary in order to shed light on the taxonomic position of these two genuses. On the other hand, we analyzed 403 bp of the ND1 sequence of 43 individuals of M. gregaria from different localities: 12 from the Beagle Channel, four from the Strait of Magellan, eight from the Burdwood Bank, five from Puerto Madryn, four from Golfo San Jorge, six from Puerto Montt, and four from Otago. We found 19 haplotypes defined by 19 variable sites. The topology of the haplotype network revealed the existence of a central, most common haplotype, present in South America from which other 18 haplotypes derive. Twenty two individuals of both morphs shared the most common haplotype: six from the Beagle Channel, two from the Strait of Magellan, six from the Burdwood Bank, four from Puerto Madryn and four from Puerto Montt. From the rest of the haplotypes found, 15 differed from the most common one in one or two mutational steps, and two of these were only found in New Zealand. The other three haplotypes differed in four (one individual of morphotype “subrugosa” from Puerto Madryn), six (two “subrugosas” from Otago) and eight (one “subrugosa” from Burdwood Bank) mutational steps from the most common haplotype. Based on the geographic location of the most ancestral haplotype, it is probable that southern South America has been the center of origin of this species. However, more individuals from New Zealand are currently being studied in order to test this hypothesis.