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Article
Morphometric Convergence and Molecular Divergence: the Taxonomic Status and Evolutionary History of Gymnura crebripunctata and Gymnura marmorata in the Eastern Pacific Ocean
Journal of Fish Biology
  • W. D. Smith, Moss Landing Marine Laboratories
  • J. J. Bizzarro, Moss Landing Marine Labotratories
  • Vincent P. Richards, Nova Southeastern University
  • J. Nielsen, Nova Southeastern University
  • F. Marquez-Flarias, Instituto Nacional de la Pesca - Mexico
  • Mahmood S. Shivji, Nova Southeastern University
Document Type
Article
Publication Date
9-23-2009
Keywords
  • Gymnuridae,
  • Mitochondrial DNA,
  • Phylogeography,
  • Sexual dimorphism
Peer Reviewed
1
Abstract
To clarify the taxonomic status of Gymnura crebripunctata and Gymnura marmorata, the extent of morphological and nucleotide variation between these nominal species was examined using multivariate morphological and mitochondrial DNA comparisons of the same characters with congeneric species. Discriminant analysis of 21 morphometric variables from four species (G. crebripunctata, G. marmorata, Gymnura micrura and Gymnura poecilura) successfully distinguished species groupings. Classification success of eastern Pacific species improved further when specimens were grouped by species and sex. Discriminant analysis of size-corrected data generated species assignments that were consistently accurate in separating the two species (100% jackknifed assignment success). Nasal curtain length was identified as the character which contributed the most to discrimination of the two species. Sexual dimorphism was evident in several characters that have previously been relied upon to distinguish G. crebripunctata from G. marmorata. A previously unreported feature, the absence of a tail spine in G. crebripunctata, provides an improved method of field identification between these species. Phylogenetic and genetic distance analyses based on 698 base pairs of the mitochondrial cytochrome b gene indicate that G. crebripunctata and G. marmorata form highly divergent lineages, supporting their validity as distinct species. The closely related batoid Aetoplatea zonura clustered within the Gymnura clade, indicating that it may not represent a valid genus. Strong population structuring (overall ΦST = 0·81,P < 0·01) was evident between G. marmorata from the Pacific coast of the Baja California peninsula and the Gulf of California, supporting the designation of distinct management units in these regions.
Comments

©2009 The Authors

ResearcherID
G-4080-2013
DOI
10.1111/j.1095-8649.2009.02300.x
Citation Information
W. D. Smith, J. J. Bizzarro, Vincent P. Richards, J. Nielsen, et al.. "Morphometric Convergence and Molecular Divergence: the Taxonomic Status and Evolutionary History of Gymnura crebripunctata and Gymnura marmorata in the Eastern Pacific Ocean" Journal of Fish Biology Vol. 75 Iss. 4 (2009) p. 761 - 783 ISSN: 0022-1112
Available at: http://works.bepress.com/mahmood-shivji/84/