mtdna

Abstract: The geographic partition of genetic variation, also known as population structure, is an essential attribute of a species’ biology and a useful tool for resource managers to make informed decisions for the protection and long-term preservation of the species. Among the most severe deteriorations of coral reefs have been recorded in the Caribbean Sea and such biological knowledge from key species could assist stakeholders to construct sound management plans. The population structure of the iconic Caribbean Sea fan, Gorgonia ventalina Linnaeus, 1758, was estimated from DNA sequences of the mitochondrial marker MutS Like Homolog protein 1 (MSH1) and the nuclear marker Signal Recognition Particle 54 intron (SRP54). Samples encompassed most of the species’ known distribution from Curaçao to Florida, the Lesser Antilles to Panamá, and Bermuda. Analysis of molecular variance revealed a significant amount of population differentiation between the eastern and western Caribbean with the MSH1 gene, however, no such signal was detected with the SRP54 intron. The Old Buoy and Mario reefs of western and southwestern Puerto Rico were the most genetically differentiated among all sites based on the MSH1 gene. Local current patterns at the reef level and low sample sizes are possible explanations for the observed patterns of genetic differentiation. Comparisons with other studies using microsatellites and SNPs, including a study with G. ventalina suggests that faster-evolving genomic areas are more appropriate markers for the detection of fine-scale population differentiation in G. ventalina. 

Abstract

The Lesser Antilles, in the Eastern Caribbean, is inhabited by three Iguana species: the Lesser Antillean iguana Iguana delicatissima, which is endemic to the northernmost islands of the Lesser Antilles, the introduced common iguana from South America, Iguana iguana iguana, represented also by the two newly described endemic subspecies Iguana iguana sanctaluciae from Saint Lucia and Iguana iguana insularis from Saint Vincent and the Grenadines, and Grenada, and the introduced Iguana rhinolopha from Central America. Drawing on both morphological and genetic data, this paper describes the Iguana populations from Saba and Montserrat as a new species, Iguana melanoderma. This species is recognized on the basis of the following combination of characteristics: private microsatellite alleles, unique mitochondrial ND4 haplotypes, a distinctive black spot between the eye and tympanum, a dorsal carpet pattern on juveniles and young adults, a darkening of body coloration with aging (except for the anterior part of the snout), a black dewlap, pink on the jowl, the high number of large tubercular nape scales, fewer than ten medium sized–triangular dewlap spikes, high dorsal spikes, and lack of horns on the snout. This new melanistic taxon is threatened by unsustainable harvesting (including for the pet trade) and both competition and hybridization from escaped or released invasive alien iguanas (I. iguana iguana and I. rhinolopha) from South and Central America, respectively. The authors call for action to conserve Iguana melanoderma in Saba and Montserrat and for further research to investigate its relationship to other melanistic iguanas from the Virgin Islands and coastal islands of Venezuela.

Keywords: Conservation Biology, Iguana, Lesser Antilles, microsatellites, mtDNA, new endemic species, phylogeny