Phylogenetic and phylogeographic inferences based on two DNA markers reveal geographic structure of the orangeclaw hermit crab Calcinus tibicen (Anomura: Diogenidae) in the western Atlantic

ABSTRACT

The hermit crab Calcinus tibicen has an extensive distribution along the coasts of the western Atlantic Ocean, from the USA to southern Brazil. The present study aimed to test the hypothesis of the presence of phylogeographic structure of C. tibicen throughout its distribution, evaluating the genetic and morphological variabilities of the species. The molecular data, genetic diversity and demographic history were inferred from 16 different localities for the mitochondrial genes cytochrome oxidase subunit I (COI) (75 specimens) and 16S rRNA (20). The morphological information was based on 99 individuals from the same 16 localities. Results were obtained by the construction of haplotype networks and a phylogenetic tree, an Analysis of Molecular Variance (AMOVA), Tajima’s D and Fu’s Fs tests, pairwise mismatch distributions under the sudden expansion model, and by estimating divergence times. The haplotype networks show the existence of two genetically well-defined groups that do not share haplotypes. The phylogenetic tree and the matrix of genetic distances suggest lack of gene between North and South Atlantic groups, also corroborated by AMOVA for the COI gene. The genetic distance can be attributed to at least two ecological factors: the existence of a physiological barrier caused by the Amazon River freshwater plume, and the effect of the bifurcation of the westerly flowing South Atlantic oceanic currents creating a gap along the Brazilian coastline. Demographic history analyses suggest that C. tibicen experienced population expansion, probably after the Amazon River changed its direction. Despite the molecular evidence for the existence of a phylogeographic structure, no morphological pattern for each genetic group was observed. Therefore, based on the described molecular differences and the ecological and historical factors suggested, the question arises whether a cryptic species should be recognized for some of the populations of C. tibicen.

SUBJECT EDITOR:

• Torsten Struck

KEYWORDS:

• Genetic heterogeneity
• mitochondrial genes
• phylogeography
• population genetics
• 16S
• COI

Acknowledgements

We would like to thank Darryl L. Felder (University of Louisiana, USA), Gustav Paulay (University of Florida, USA), Ingo Wehrtmann (Universidad de Costa Rica), José Luis Villalobos and Fernando Alvarez (Universidad Nacional Autónoma de Mexico), Rachel Collin (Smithsonian Tropical Research Institute – STRI) for loans, donations, logistics and collecting permits. We thank anonymous reviewers for their suggestions that helped to improve the quality of this paper during the revision process.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Silvia Sayuri Mandai http://orcid.org/0000-0002-9260-5327

Raquel Corrêa Buranelli http://orcid.org/0000-0002-3092-9588

Fernando L. Mantelatto http://orcid.org/0000-0002-8497-187X

Additional information

Funding

This article resulted from the Bachelor’s thesis of SSM who was supported by a scientific fellowship from São Paulo Research Foundation – FAPESP (2014/10639-1). Major financial support for this project was provided by FAPESP (Procs. 2002/08178-9, Temático Biota 2010/50188-8; Coleções Científicas 2009/54931-0), Conselho Nacional de Desenvolvimento Científico e Técnológico – CNPq (Procs. 472746/2004-9, 491490/2004-6, 473050/2007-2, 471011/2011-8, 490353/2007-0; 490314/2011-2; 504322/2012-5; PROTAX 440417/2015-5 Research Scholarships PQ 302748/2010-5, 304968/2014-5) and by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – CAPES (Ciências do Mar II 2005/2014 – 23038.004308/2014-14) to FLM. CDS and FLM thank the International Cooperative Project – CAPES/DAAD (Proc. 315/09) for financial support during a Brazil-Germany exchange programme that made possible the formation of ideas, analyses of the material and discussion of the obtained data. RCB received a Post-Doctoral fellowship from CNPQ (PROTAX 150462/2016-6).