Molecular phylogenetic analyses of Tylos Audouin, 1826

Sequences obtained for the three species of Tylos from Isla Grande and the specimen from Florida have been deposited under GenBank Accession Numbers MW532964 – MW532970 and MW533069 – MW533075. Only the 12S rDNA sequence was obtained for the specimen from Isla Grande assigned to T. marcuzzii . Phylogenetic analyses using only 12S rDNA group this sequence with the two specimens of T. marcuzzii from Cuba reported in Hurtado et al. (2014); see Fig. 18. The 12S rDNA p-distance between T. marcuzzii from Isla Grande and T. marcuzzii from Cuba is 2.0–2.7%, whereas the distance between the specimens from the two Cuban localities is 2.0% (Table 2). Only the 16S rDNA sequence was obtained for the specimen of T. niveus from the Florida Keys, the type locality of this species. Phylogenetic analyses of 16S rDNA show that specimens identified as T. niveus from Isla Grande are most closely related to the T. niveus specimen from the Florida Keys. The 16S rDNA p-distance between T. niveus from Isla Grande and the Florida Keys is 2.7% (Table 2).

The concatenated (12S rDNA and 16S rDNA) dataset was comprised of 43 taxa and 740 characters (excluding characters with ambiguous homology), 236 of which were parsimony-informative. The specimens assigned to T. marcuzzii were used as outgroup. Five main lineages were identified for the ingroup taxa in the concatenated phylogenetic analyses, which formed a basal polytomy (Fig. 18): (1) T. niveus from Puerto Rico; (2) Tylos sp. from Yaguanabo, Cuba; (3) T. niveus from Florida and Isla Grande; (4) T. negroi sp. nov.; and (5) Tylos punctatus sensu lato from the Northeastern Pacific. The range of 16S rDNA and 12S rDNA p-distances between the four basal lineages excluding T. punctatus is 11.1–13.6% and 9.7–15.5%, respectively. The range of 16S rDNA and 12S rDNA p-distances between these ingroup lineages and T. marcuzzii is 19.4–22.2% and 19.5–23.8%, respectively.