title: Multigene molecular systematics confirm species status of morphologically convergent Pagurus hermit crabs.
abstract: BACKGROUND
  In spite of contemporary morphological taxonomy appraisals, apparent high morphological similarity raises uncertainty about the species status of certain Pagurus hermit crabs. This is exemplified between two European species, Pagurus excavatus (Herbst, 1791) and Pagurus alatus (Fabricius 1775), whose species status is still difficult to resolve using morphological criteria alone.
  
  
  RESULTS
  To address such ambiguities, we used combinations of Maximum Likelihood (ML) and Bayesian Inference (BI) methods to delineate species boundaries of P. alatus and P. excavatus and formulate an intermediate Pagurus phylogenetic hypothesis, based upon single and concatenated mitochondrial (cytochrome oxidase I [COI]) and nuclear (16S and 28s ribosomal RNA) gene partitions. The molecular data supported the species status of P. excavatus and P. alatus and also clearly resolved two divergent clades within hermit crabs from the Northeast Atlantic Ocean and the Mediterranean Sea.
  
  
  CONCLUSIONS
  Despite the abundance and prominent ecological role of hermit crabs, Pagurus, in North East Atlantic Ocean and Mediterranean Sea ecosystems, many important aspects of their taxonomy, biology, systematics and evolution remain poorly explored. The topologies presented here should be regarded as hypotheses that can be incorporated into the robust and integrated understanding of the systematic relationships within and between species of the genus Pagurus inhabiting the Northeast Atlantic Ocean and the Mediterranean Sea.
authors.affiliation: Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Environment Centre for Wales, Bangor University, Bangor, Wales, United Kingdom. joanamatzen@yahoo.com
authors.forename: Joana
authors.initials: J
authors.lastname: Matzen da Silva
authors.forename: Antonina
authors.initials: A
authors.lastname: Dos Santos
authors.forename: Marina R
authors.initials: MR
authors.lastname: Cunha
authors.forename: Filipe O
authors.initials: FO
authors.lastname: Costa
authors.forename: Simon
authors.initials: S
authors.lastname: Creer
authors.forename: Gary R
authors.initials: GR
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D033381:Anomura / Q000033:anatomy & histology* / Q000235:genetics*; D001267:Atlantic Ocean; D001483:Base Sequence; D001499:Bayes Theorem; D030541:Databases, Genetic; D003576:Electron Transport Complex IV / Q000235:genetics; D014644:Genetic Variation; D008522:Mediterranean Sea; D008957:Models, Genetic; D005810:Multigene Family / Q000235:genetics*; D009711:Nucleotides / Q000235:genetics; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D009711:Nucleotides; D003576:Electron Transport Complex IV