Some good news to make your holidays a little happier: a new population of critically endangered yellow-tailed woolly monkey (Oreonax flavicauda) was discovered recently!
To Oreonax or to Lagothrix–that is the question!
The yellow-tailed woolly monkey is a member of the Atelidae family (howler and spider monkeys) within its own unique genus, Oreonax. This taxonomic decision has come under some criticism of the legitimacy by using Oreonax as a genus compared to the genus of its closer relatives, Lagothrix, based on a parsimony analysis of incomplete taxonomic sampling on available skulls (Matthews and Rosenberger 2008). For the purposes of taxonomy, I’d be more likely to agree with Matthews and Rosenberger’s detailed analysis and recommendation of Lagothrix; however, for conservation purposes, I would absolutely recommend the purpose of using Oreonax from a flagship species perspective.
As Mace (2004) argues, government policies tend to favor unique species–especially the species which tend to indicate a problem of decline. As it just so happens, the yellow-tailed woolly monkey is critically endangered and, unfortunately, a member of one of the 25 most endangered primates in the world. Both of these elements combined alone probably make an appealing case for the yellow-tailed woolly monkey to receive a lot of conservation attention. And if that’s the case, then why bother with making it a genus all its own? Simply put: we still don’t know a lot about the yellow-tailed woolly monkey.
Even though the yellow-tailed woolly monkey was discovered in 1812 by Alexander von Humboldt (who initially thought it was a species of howler monkey), there was not enough information to classify the primate properly until 1963 (DeLuycker 2007). Additionally worth noting as far as available information goes on this species, there has also been no long-term study on this species since 1982 (DeLuycker 2007).
As it stands, with our given knowledge about the yellow-tailed woolly monkey, it would certainly not be harmed to be considered its own unique genus for conservation purposes. Although it is certainly a case of splitting a genus, it is largely based on parsimonous morphological analysis as opposed to genetic reasoning.
Oreonax flavicauda: getting to know you, getting to know all about you
As previously stated, there is still quite a bit of information unknown about the yellow-tailed woolly monkey. But here’s what we do know about it:
The yellow-tailed woolly monkey is endemic to Peru, and largely resides in the montane cloud forests on steep gorges and ravines around 1,500-2,600 m with canopy heights of 20-25 m (Shanee et al. 2008). As such, as an adaptation to its colder climate, the primate is characterized by having thicker, darker fur with a copper hue and a yellow coloring on the ventral side of the prehensile tail tip (DeLuycker 2007). Hence, the “woolly” and “yellow-tailed” name. The range of temperatures in this climate can range anywhere from, on average, a low of 8˚C (46.4˚F) to a high of 25˚C (77.0˚F) (Leo Luna 1980). Like other Atelids, the yellow-tailed woolly monkey is folivorous, but will also consume fruits, insects, lichens, buds, bulbs, flowers, epiphyte roots, and petioles (DeLuycker 2007; Leo Luna 1980;1987; Butchart et al. 1995).
A lot of the listed foods, to me, suggest a large diet on subsistence, fallback foods as opposed to a higher-quality item like fruit as these items are more readily available. However, and this surely plays a role in the threatened status of the primate, much of the dietary resources are at risk for being lost due to mining (Shanee & Shanee 2010). Other additional threats to the yellow-tailed woolly monkey include: deforestation due to road building, hunting pressures, climate change, and habitat stress (DeLuycker 2007; Shanee & Shanee 2010).
So what about the new kids on the block?
The fact that we’ve found an extra population is inspiring: given that we don’t know a terrible lot about this species, it’s entirely possible there are more populations out there. The important thing is that we are able to keep the populations consistent with the 50/500 rule posed by Franklin (1980) and Soule (1980).
We know there are more than 250 individuals left in the wild, which gives them a fighting chance to beat the temporary causes above the 50 individuals needed for continuing heterozygote genes (in order to avoid deletrious alleles) in the proximate, temporary period of time. However, ultimate, long-term factors suggest a dismal future for the yellow-tailed woolly spider monkey if population trends continue to decline; 500 individuals would be more likely to ensure a rapid rate of heterozygosity to avoid a natural selection culling based on homozygotic traits.
I’m not entirely convinced that we can pull these guys back from the brink based on 250+ individuals alone, but the closer we get to 500, the better the chances are.
Butchart, S.H.M., Barnes, R., Davies, C.W.N., Fernandez, M., Seddon, N. (1995). Observations of two threatened primates in the Peruvian Andes. Primate Conservation, 16, 15-9.
DeLuycker, A.M. (2007). Notes on the Yellow-tailed Woolly Monkey (Oreonax flavicauda) and its Status in the Protected Forest of Alto Mayo, Northern Peru, Primate Conservation, 22, 41-47
Franklin, I.R. (1980). Evolutionary changes in small populations. In: Soule M., Wilcox, B.A. (eds) Conservation biology: an evolutionary-ecological perspective. Sinauer Associates, Sunderland, 135-149.
Leo Luna, M. (1980). First Field Study of the Yellow-tailed Woolly Monkey Oryx, 15 (04), 386-389 DOI: 10.1017/S0030605300028908
Leo Luna, M. (1987). Primate conservation in Peru: a case study of the yellow-tailed woolly monkey. Primate Conservation, 8(122).
Mace, G. (2004). The role of taxonomy in species conservation, Philosophical Transactions of the Royal Society B: Biological Sciences, 359 (1444), 711-719 DOI: 10.1098/rstb.2003.1454
Matthews, L., & Rosenberger, A. (2008). Taxon combinations, parsimony analysis (PAUP*), and the taxonomy of the yellow-tailed woolly monkey, American Journal of Physical Anthropology, 137 (3), 245-255 DOI: 10.1002/ajpa.20859
Shanee S., Shanee N., & Maldonado A.M. (2008). Distribution and conservation status of the yellow-tailed woolly monkey Oreonax flavicauda in Amazonas and San Martín, Perú. Neotropical Primates 14: 115–119.
Soule, M. (1980) Thresholds for survival: maintaining fitness and evolutionary potential. In: Soule M., Wilcox, B.A. (eds) Conservation biology: an evolutionary-ecological perspective. Sinauer Associates, Sunderland, 151–169.