Vonones ornatus, one of the few species of Cosmetidae found in the southern United States. Photo by Lynnette Schimming from Bug Guide.
The systematics of South American harvestmen have long been one of the taxonomic world's God-awful messes, with the painstaking work of Pinto-da-Rocha, Kury and associates only recently managing to go some way towards drawing it from the mire. The blame for this morass can be placed almost entirely with a single person - Carl-Friedrich Roewer, who described about a third of the world's total of harvestmen species, some 2,260 taxa. He was able to attain this prodigious output by employing a highly artificial mode of classification. Individual specimens were assigned to species and species assigned to higher taxa on the basis of quite superficial characters such as the number of sub-segments in the legs or the number of spines on the abdomen. Character systems such as genitalia that are now regarded as highly significant were not considered*. Many of the features used by Roewer have since turned out to be variable within individuals of a single species, and sometimes within a single individual - in the case of number of tarsal segments, more than one author (such as Hickman, 1939) has described specimens that have differing numbers of segments on the left side from the right, which would require that each side belong to a different genus, if not subfamily!
*To be fair, Roewer could probably be forgiven for his neglect of genitalic characters. While genitalia had been used by some authors in taxonomy by the early 1900s, the practice was not yet widespread and its importance not widely recognised.
It has to be said that the names he gave his excessive outpourings of taxa were not exactly inspired either. Many of them were derived by sticking some suffix or prefix onto a pre-existing name. For instance, from the original name Cynorta, he gave us Cynortula, Cynortoides, Eucynorta, Cynortella, Cynortellana, Cynortellina, Eucynortula, and I'll stop now before my head explodes. Trust me, there's a lot more. To quote Kury (2003), "The dreadful, uninspired and sometimes cumbersome names created by Roewer and Mello-Leitão and followers, and which are deformations of place names, people's names and (the worst!) pre-existing generic names, are best left alone."
The above-listed genera belong to the family Cosmetidae, one of the largest harvestman families in the Neotropics. While still officially divided into two subfamilies, these are divided solely by whether the claws on legs III and IV are smooth or pectinate and this distinction is not expected to stand up to proper phylogenetic analysis should one ever be conducted (Kury & Pinto-da-Rocha, 2007). While the work of Kury and associates has vastly improved matters with the Gonyleptidae, the other major Neotropical family of short-legged harvestmen*, the Cosmetidae remain almost untouched by modern researchers**.
*Harvestmen fall into three groups, the mite-like, long-legged and short-legged harvestmen. I covered mite-like harvestmen once before. Long-legged harvestmen are the daddy-long-legs type harvestmen. Short-legged harvestmen are generally more heavily armoured, and while they do tend to have shorter legs than long-legged harvestmen, they probably have what would be fairly long legs for any other group of animal. The first episode of Life in the Undergrowth included footage of egg-guarding behaviour in a short-legged harvestman.
**Fortunately, I have reasons, such as the publication of Kury et al. (2007), to hope this may change over the coming years.
The genus Cynortula Roewer, 1912, as it currently stands, contains 32 species from throughout tropical Central and South America, from Mexico and the Bahamas to Bolivia and Brazil (the illustration above, from Goodnight & Goodnight, 1947, shows Cynortula granulata from Trinidad). Lord only knows what will happen to this genus in the future, however. Roewer (1923) seems to have supplied the last description of the genus, and described it as "Schlanke Tiere mit langen, dünnen Beine. 1. und 3. Area mit je 1 mittlerer Tuberkel-Paar; 2., 4. und 5. Area und 1.-3. frei Tergit unbewehrt. 2. Chelicere-Glied auch beim ♂ klein und normal gebaut oder seltener beim ♂ viel dicker als beim ♀ unten oben das 1. Chelicere-Glied weit überragend. Beine: die basal Glied des 3. und 4. Bein auch beim ♂ von gleichem Habitus und gleicher Stärke wie die des 1. und. 2. Bein; Endabschnitt des 2. Tarsus 3-gliedrig; 1. Tarsus 6-gliedrig; 2.-4. Tarsus jeweils mehr als 6-gliedrig, variabel. Sekundäre Geschlechtsmerkmale des ♂ bisweilen am 4. Bein."* This roughly translates (if I translate it correctly through the gibberish of BabelFish) as "Slim animals with long, thin legs. 1st and 3rd areas always with 1 central pair of tubercles; 2nd, 4th and 5th areas and 1st-3rd free tergites unarmed. 2nd cheliceral segment of ♂ small and normally built or more rarely with ♂ much larger than ♀. Legs: basal segments of 3rd and 4th legs the same as 1st and 2nd legs; Final section of 2nd tarsus 3-segemented; 1st tarsus 6-segmented; 2nd-4th tarsus in each case more than 6-segmented, variable. Secondary sexual characteristics sometimes present in 4th leg of ♂." For those not familiar with variation in harvestmen, that's not a very impressive list of distinguishing features. In fact, in Roewer's key to the Cosmetidae, only one character is used to key Cynortula out from similar genera - whether the dorsal ornamentation is a tubercle (Cynortula) or a spine (other genera). Not convincing.
*If there are any German speakers reading this, I apologise profusely for the errors that I have no doubt are all through that. As a result of its publication not too long after the Great War, with materials in short supply in Germany, Roewer (1923) was condensed as much as possible for publication and hence is entirely composed in a series of arcane abbreviations. Any grammatical errors are therefore probably the result of my attempts to restore the description to a readable form.
Hickman, V. V. 1939. Opiliones and Araneae. British, Australian and New Zealand Antarctic Research Expedition Reports Series B 4: 157-188.
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.
Kury, A. B., & R. Pinto-da-Rocha. 2007. Cosmetidae. In Harvestmen: The Biology of Opiliones (R. Pinto-da-Rocha, G. Machado & G. Giribet, eds.) pp. 182-185. Harvard University Press: Cambridge (Massachusetts).
Kury, A. B., O. Villarreal-Manzanilla & C. Sampaio. 2007. Redescription of the type species of Cynorta (Arachnida, Opiliones, Cosmetidae). Journal of Arachnology 35 (2): 325-333.
Roewer, C. F. 1923. Die Weberknechte der Erde: Systematisches Bearbeitung der bisher bekannten Opiliones. Gustav Fischer: Jena.