[OANNES Foro] Lack of cryptic diversity in a cosmopolitan parasite of mole crabs

[Mario Cabrejos]

Journal of Biogeography

 <http://onlinelibrary.wiley.com/doi/10.1111/jbi.2014.41.issue-5/issuetoc>
Volume 41, Issue 5, pages 965-976, May 2014

Article first published online: 15 JAN 2014

DOI: 10.1111/jbi.12260


 


 


Phylogeography of a marine acanthocephalan: lack of cryptic diversity in a
cosmopolitan parasite of mole crabs


1.     Tricia C. Goulding1,2 and C. Sarah Cohen1,*

1Romberg Tiburon Center for Environmental Studies, Biology Department, San
Francisco State University, Tiburon, CA, USA2Pennsylvania State University,
University Park, PA, USA * Correspondence: E-mail:
<mailto:sarahcoh en sfsu.edu> sarahcoh en sfsu.edu


 


Abstract


Aim


Little is known about phylogeography and cryptic diversity of parasites in
the marine environment. The acanthocephalan Profilicollis altmani
parasitizes intermediate hosts that are broadly distributed around the
Americas and final hosts that are highly motile. We investigated the spatial
genetic structure of this acanthocephalan found in three species of Emerita
crabs: (1) to test whether land masses serve as biogeographic barriers
promoting ocean basin divergence among parasite lineages or species; and (2)
to test whether the distribution of parasite species matches the
distribution of different crab host species.


Location


The Pacific, Atlantic and Gulf coasts of the USA, and the Pacific coast of
Panama and Chile.


Methods


Sequences of cytochrome c oxidase subunit I (COI) and ribosomal internal
transcribed spacers (ITS) were obtained from 204 acanthocephalans. Parasites
were sampled from crabs in 15 sampling localities. These sequences were
analysed with coalescent-based methods and other population genetic analyses
to infer phylogeographic patterns.


Results


Haplotype diversity for COI sequences was high (0.96) among parasites
sampled, but nucleotide diversity was low (0.071) and there was no distinct
geographic pattern between regions. Pairwise genetic distances were
generally low, although there was a degree of population structure between
oceans. Sequence comparisons showing an excess of low divergence alleles and
a bimodal mismatch distribution provide evidence of either past selective
events or demographic expansions. No variation was observed in the ITS
sequences.


Main conclusions


The lack of geographic patterning in haplotype diversity of this parasite
indicates that gene flow is probably occurring between ocean basins. In
addition, the low genetic diversity suggests that the acanthocephalan
parasitizing E. analoga in Chile is conspecific to the species found
parasitizing several Emerita species along the coasts of North America, and
is thus a cosmopolitan parasite that is most likely dispersed long distances
by marine birds that serve as definitive hosts.

 



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