Two new species of the blenny genus Emblemariopsis, E. carib and E. arawak, have recently been described from the Caribbean.
Both species names are nouns in apposition and are the names of native peoples of the Antilles. The two species are found sympatric on coral reefs off Puerto Rico and the nearby U.S. Virgin Islands, and may be more widespread.
Emblemariopsis is a genus of tiny blennies whose distribution is restricted to the tropical western Atlantic. It contains a dozen or so described species, and probably many more as yet undescribed, all of which are found in association with reefs (coral and rocky).
Like a number of other groups from the region they present major taxonomic difficulties, specifically in that they exhibit both overlap in some important morphological characters, and high intraspecific variability in others as well as in markings. In other words, counts and measurements are not diagnostic and nor is coloration. In addition, mature males have territorial and non-territorial morphs, both very different in appearance from females, and in the case of some species only one sex is so far known to science.
It is against this chaotic background that the two new species have now been described.
Until recently both were thought to be populations of the Flagfin blenny, E. signifer, which was originally described from the coast of Brazil and on paper is the commonest member of the genus, although many reports may refer to other, undescribed taxa.
DNA study has now shown that the new species are distinct from E. signifer and from each other, and the genetic distances between the three species are so great that they have probably been separate entities for over a million years! The new species are also smaller than their Brazilian cousin and there are also minor differences in morphology and coloration, but because of the high degree of intraspecific variability it is difficult to establish any reliable diagnostic characters.
The photo above is of a male from the Dominican Republic that appears identical with E. carib, but because no DNA studies have as yet been performed on that population it is not possible to be certain. Hence it is for the time being identified as E. cf. carib.
For further information and additional photos see the paper: Victor, B.C. (2010) Emblemariopsis carib and Emblemariopsis arawak, two new chaenopsid blennies from the Caribbean Sea: DNA barcoding identifies males, females, and juveniles and distinguishes sympatric cryptic species.