Guenon Radiation is Enriched by a New Species that Demonstrates an Evolutionary Complexity with Which we are yet to Become Familiar

Abstract

th September described this discovery to the scientific community (1). As is becoming increasingly frequent these days, given the high number of scientific articles, the media news reached us faster than the scientific information. The area known as TL2, a few hundred km as the crow flies south- west from the city of Kisangani, famous for its manufacturing, and important port on the Zaire river, is still uncontaminated and houses several important endemisms. This new species, studied in the area since 2007, on the basis of first sightings by the inhabitants of the zone and local hunters, has been named Cercopithecus lomamiensis. C.lomamiensis (CLO) is a tree-dweller and has been described in secondary forest ecology but climbs down to the ground with a certain regularity, foraging for seasonal herbs, things which many tree dwelling guenons do, even daily. Guenon's tree dwelling habit is never complete and should be intended in a critical sense (this would avoid unsatisfactory scholastic phylogenetic interpretations). The discovery and description of this new species, which required this long study, including circumstantial evidences, in order to ascertain the exact specific status, are of extreme interest in the study of the evolution, biogeography and conservation of this varied and fascinating type of African arboreal primate (2) that remains still very uncertain. The article in PlosOne analyses in a very detailed way this new species which at first sight, comprises characteristics which are common for its type: slender postcranial structure, undifferentiated, and multicoloured pattern. While the colours of its mantle reminds one of C.mitis, or mona group, the distribution of fur on the borders of the face and ears (but not on the crown) and the intense sky blue colouration of the scrotal and perineal area are something it has in common with C.hamlyni (CHA). Among the facial characteristics of C. lomamiensis one can observe a resemblance to C. hamlyni, something in the profile, a streak of lighter fur along the nose (however, nothing in comparison to the intensity of that of the CHA). CLO can mainly be distinguished from C. hamlyni, apart from its complete geographical separation, by the colours of the mantle, and for its generally less robust body. Moreover, although the cranial morphology and the sagittal profile are similar with CHA, the morphometric investigation designates principle traits of two distinct morphologies. On the contrary, if the morphological analysis does not lean towards a satisfactory relationship, what these two species seem to have most in common are the genetic traits resulting from the analysis of the loci of sexual chromosomes (TSPY and Xq13.3) which, despite indicating different divergent chronologies, both interspecific and intraspecific, unite the two taxa and separates them from the complicate radiation of the guenons. On this base the monotypic C. hamlyni group (3) enriches now of another component, different indeed, but presumably related on a genetic base. Further, it is now necessary to revise the taxonomic key to the superspecies, as C. hamlyni (sp. g.), was since now included in the species with prevailing colour not greenish, as its pelage is very dark (greenish olive speckled heavily with black, and with pearl grey tips). It should be interesting to know if in previous studies this taxon has been never met and tentatively described. Museum collection are full of samples that have given, and can still give interesting surprises.Thomas and Wroughton (4) described a variant of C. hamlyni (Cercopithecus leucampix aurora), where the yellow was predominant in the coat. It was tentatively compared with samples belonging to the C. mitis group, but the sample was too incomplete for an exhaustive analysis. Long time passed without certainties and the C. hamlyni remained for one hundred years alone in its peculiar group (5).