Biochemical genetic evidence supporting the taxonomic separation of Loligo edulis and Loligo chinensis (Cephalopoda: Teuthoidea) from the genus Loligo

Confusion abounds regarding the relative generic status of many member species of the squid family Loliginidae. A taxonomic reorganisation within the family has been proposed in which Loligo species from the Indo-Pacific possessing photophores on the ink sac, including Logligo edulis and Loligo chinensis, are removed to the newly created genus Photololigo. This system of classification has not however gained general acceptance, and some authors have continued to refer to these species as Loligo. Here biochemical genetic data gathered using allozyme electrophoresis are presented supporting the assertion that L. edulis and L. chinensis should indeed be positioned in a genus distinct from that characterised by the type species Loligo vulgaris vulgaris. Cluster analysis of allele frequency data from 22 putative enzyme-coding loci suggests that L. edulis and L. chinensis are as genetically distant from L. vulgaris vulgaris as are members of the confamilial genera Alloteuthis, Uroteuthis and Sepioteuthis, and as such warrant separate generic status. We conclude that the genus Photololigo is valid.