Nesocyrtosoma (Coleoptera: Tenebrionidae): A classic Greater Antillean/Montserrat distribution

The results of a revision of Nesocyrtosoma Marcuzzi reveal a historically confused and under-described genus that exhibits the Greater Antillean distribution predicted by a vicariant-mobilist model, with sub-radiations on Cuba, Hispaniola and the Puerto Rican Bank. These clusters of endemic island faunae on Cuba (14 species), Hispaniola (25 species), and the Puerto Rican Bank (2 species) indicate intra-island speciation has occurred. The absence of Jamaican species indicates the taxon originated with the Proto-Antilles, as many such groups show extensive radiation in the Greater Antilles but do not occur on Jamaica. This is hypothesized to be the result of its independent emergence in the late Miocene, 10 million years later than the emergence of the other Greater Antillean islands. However, the discovery of a Lesser Antillean species endemic to Montserrat provides an interesting outlier. The existence of this single species of Nesocyrtosoma on the relatively young volcanic island (Pliocene, ~4.4 Ma) begs several questions regarding vicariant vs. over-water distribution patterns. Although a satisfactory explanation has not been found, Nesocyrtosoma adds to the expanding list of taxa with Greater Antillean/Montserrat distributions.