Species boundaries in the starfish genus Linckia

Abstract

 The genetic basis for species boundaries in the starfish genus Linckia was examined using variation observed in 613 base pairs (bp) of sequence from the cytochrome oxidase I gene of mtDNA and 16 allozyme loci. Five groups within Linckia were clearly genetically differentiated; L. columbiae, L. bouvieri, two clades within L. guildingi, and one clade with two sub-clades consisting of both L. laevigata and L. multifora. Genetic divergence among these groups is consistent with interspecific variation. The two clades within L. guildingi suggest the presence of a cryptic, partially sympatric, species. Genetic divergence between these two clades implies that they have been genetically distinct from each other for at least one million years. In contrast, genetic data suggest that L. laevigata and L. multifora are a single species, despite the fact that live individuals can be distinguished by their colour and colour pattern, number of madreporites and ratio of arm length to breadth. There are probably three closely related groups within the L. laevigata/L. multifora clade –L. multifora, and two groups in L. laevigata defined by biogeographic province. It is difficult to determine boundaries for these three entities, since genetic and morphological differences are complicated by phenotypic differences arising from both environmental variation and population genetic structure. The difficulties encountered in defining species boundaries in Linckia, particularly with respect to variation arising from the overlap of Indian and Pacific biogeographic provinces, may be a general issue for many marine organisms from this region.

This is a preview of subscription content, log in to check access.

Author information

Affiliations

Authors

Additional information

Received: 24 May 1999 / Accepted: 6 October 1999

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Williams, S. Species boundaries in the starfish genus Linckia . Marine Biology 136, 137–148 (2000). https://doi.org/10.1007/s002270050016

Download citation

Keywords

  • Genetic Divergence
  • Environmental Variation
  • Genetic Structure
  • Genetic Basis
  • Single Species