Pied Harvestmen of the Antilles

Harvestmen of the Neotropical family Cosmetidae have been featured on this site a couple of times before. Each time, I've commented on the dire taxonomic state of this diverse family, with many genera being poorly or inaccurately defined. Thanks to extensive (and continuing) studies in recent years by Braxilian researchers and their associates, this situation has been progressively improving, but we still have a lot to learn.

Cynortoides sp., copyright Damion Laren Whyte.

Cynortoides is a genus currently holding ten species of cosmetid. Most of these are found on the islands of the Greater Antilles—Cuba, Jamaica and Hispaniola—though the genus has also been recorded from adjoining regions of Mexico and Venezuela (Kury 2003). As with other cosmetids, Cynortoides has historically been defined largely be features of the external spination, including a lack of spines on the legs, two pairs of spines in the rear part of the dorsal scutum, and no spines on the free abdominal segments (Mello-Leitão 1933). Also as with other cosmetid genera, Cynortoides species are colourfully patterned. The name of one species, C. v-album, refers to its characteristic bright white V marking on the back (though personally, I would describe the pattern as more of a Y).

Though this genus does not yet appear to have been revised in detail, some of its species were included in a recent broader study of cosmetid phylogeny by Medrano et al. (2021). They found strong support for an association between the Cuban C. cubanus and the Hispaniolan C. v-album, together with two other Cuban species previously included in the related genus Cynorta. These last two species were consequently transferred to Cynortoides though Medrano et al. did not comment on whether this affected the genus' established diagnosis. The authors speculated that further studies might prove Cynortoides to be a strictly Greater Antillean genus with mainland records being misplaced. Cynortoides would not be unique in this regard: the islands of the Caribbean are home to a number of lineages found nowhere else, reflecting a long history independent of the adjoining continents.

REFERENCES

Kury, A. B. 2003. Annotated catalogue of the Laniatores of the New World (Arachida, Opiliones). Revista Ibérica de Aracnología, special monographic volume 1: 1–337.

Medrano, M., A. B. Kury & A. C. Mendes. In press 2021. Morphology-based cladistics splinters the century-old dichotomy of the pied harvestmen (Arachnida: Gonyleptoidea: Cosmetidae). Zoological Journal of the Linnean Society.

Mello-Leitão, C. F. de. 1933. Notas sobre os opiliões do Brasil. Descritos na obra postuma de Sörensen: "Descriptiones Laniatorum". Boletim do Museu Nacional 9 (1): 99–114.

source http://coo.fieldofscience.com/2021/10/pied-harvestmen-of-antilles.html