WHIDDEN, H.P.*; WOODS, C.A.: Assessment of sexual dimorphism in the Antillean insectivoran Nesophontes

The Antillean insectivoran Nesophontes is known only from subfossil material from Cuba, Hispaniola, Puerto Rico, and the Cayman Islands. When the first Nesophontes species was described from Puerto Rico, specimens appeared to fall into 2 size classes, and this size variation was interpreted as sexual dimorphism. Additional species discovered subsequently from other islands also appeared to exhibit dimorphism, though these new species were smaller and the dimorphism was less pronounced. Sexual dimorphism is minimal in extant insectivorans, and the level inferred for Nesophontes is unexpected. We used skull measurements taken on more than 1500 Nesophontes specimens to evaluate this proposed sexual dimorphism, as well as 3 alternative hypotheses for the dimorphism: temporal variation, geographic variation, and presence of additional unrecognized species. Study taxa were N. edithae from Puerto Rico and N. paramicrus, N. hypomicrus, and N. zamicrus from Hispaniola. Temporal variation and geographic variation are not supported by our data, and it is unlikely that there would be a cryptic species paired with each of these recognized species. We therefore conclude that Nesophontes did exhibit sexual dimorphism. The level of sexual dimorphism in these 4 taxa increases allometrically, with the largest species (N. edithae) exhibiting much greater dimorphism than the smallest species (N. zamicrus).