More on Marc van Roosmalen’s new Amazonian mammals: in the previous post I introduced the new dwarf tapir, as well as the whole topic of Marc’s discoveries and the coverage that they get on his new website. Part I is required reading. Here in part II we look at yet more of these animals: this time the deer, more peccaries, new small carnivores, and some big rodents…
We’ll begin with the artiodactyls: in addition to the Giant peccary (see part I and the ver 1 post here), Marc has also encountered what appear to be two additional types of peccary. One of these [shown in image above] is most closely related to the White-lipped peccary Tayassu pecari but differs from it profoundly in lacking the white lower lip and cheek margins, and in having white hooves. Marc has both kept this species in captivity and has obtained type material: the adjacent picture shows the live individual that Marc cared for at his animal sanctuary. The other new form is a dwarf, orange peccary that lives in small groups. Investigation of it is continuing. The idea that Amazonia is home to five rather than two peccary taxa is, needless to say, huge. It indicates that we have substantially under-estimated the importance of both Amazonia and South America for the evolution of the group. Wright (1998) noted that fossil assemblages never include more than three sympatric peccary species, suggesting that the diversity of the group in Amazonia may be unusually high.
Marc has also recorded two new species of brocket deer Mazama, though of all the large mammals discussed here this will perhaps be the least surprising given that a few new brocket species have been recognised in recent decades. The Bolivian dwarf brocket M. chunyi was named in 1959, and the Small red brocket M. bororo was first named in 1996 after a specimen kept at Sao Paulo’s Sorocaba Zoo demonstrated the distinctiveness of this taxon (Duarte & Gianonni 1996). What might be a new species was recently reported by Trolle & Emmons (2004) for a specimen photographed by a camera trap in 2003. One of Marc’s new brockets, the so-called White brocket, is highly distinctive in possessing shorter, more robust spike-like antlers than those of similar species, and in being an unusual whitish-brown colour [reconstruction shown in adjacent image]. It is also intermediate in size between the two sympatric brockets (M. americana and M. nemorivaga). As with so many of the mammals discussed here, Marc has procured holotype material.
Dolphin, manatee and otter
Amazonia is home not only to large terrestrial mammals, but to amphibious and aquatic ones too. Most of us are familiar with the fact that freshwater dolphins swim through the flooded forests, and there is also an Amazonian manatee Trichechus inunguis, and the Giant otter Pteronura brasiliensis, the world’s longest (though not heaviest) otter. Marc has three new amphibious/aquatic mammals that might represent new species – a new river dolphin, a dwarf manatee, and a new giant otter. The new river dolphin [shown in adjacent photo] is unique to the Rio Aripuanã and almost certainly belongs to the genus Inia. The question, however, is whether it is conspecific with I. geoffrensis, the better known of the two Boto species*. While both types of dolphin have been seen in the same area, they stay apart, and the Rio Aripuanã form is reported to be more aggressive to people and to differ from the Boto in its timing and style of exhalation. It also looks different from the Boto in being smaller, and in having a less bulbous forehead and shorter jaws. It is never pink like the Boto.
* The taxonomy of the boto has always been mildly controversial, with various people arguing at times that Inia includes two species (I. geoffrensis and I. boliviensis), while others argue that the two are conspecific. Several recent molecular studies (Banguera-Hinestroza et al. 2002, Martínez-Aguero et al 2006), and an unpublished phd thesis on cranial morphometrics, have concluded that I. geoffrensis and I. boliviensis should be recognised as distinct species.
Quite a few new cetacean species have been named within recent years, so Marc’s discovery of a new dwarf manatee, known to locals as the peixe-boi anão, is arguably more significant. Amazonia is already home to one recognised manatee, Trichechus inunguis: the dwarf species differs from it in reaching just 1.3 m and 60 kg (compared to 2.5-3 m and 350-500 kg) and in being deep black (instead of lead grey) [adjacent image shows adult male dwarf manatee. Yes, adult male. It's 1.3 m long]. The two are presumably close relatives (they certainly look more similar to each other than to either of the other two extant manatee species), and this has been confirmed by genetic analysis. A short technical paper on the manatee was submitted to a high-profile science journal, and news on its discovery has been discussed in the popular press. Like the dolphin, the dwarf manatee is restricted in distribution and has only been reported from one tributary of the Rio Aripuanã. Finally, the new otter – informally dubbed the Black giant otter – is both morphologically and behaviourally distinct from P. brasiliensis. It is not only darker than this species, but also somewhat smaller. All three of these mammals appear to represent dwarf endemic forms of larger, more widespread species.
Big rodents and small carnivores
Two small carnivorans and two big rodents are among the new taxa. A new form of tayra, known locally as the irara-vermelho, is orange-brown and lacks the throat patch present in Eira barbara. The second carnivoran is a new large coati: it is about twice as large as the Common coati Nasua nasua, and different from it in being more orange, in being more arboreal, and in its postures and social structure (it lives in pairs, rather than in the large groups that are most typical for the Common coati) [new coati shown in adjacent photo]. Incidentally, another reportedly new coati species is supposedly being described by Peter Hocking and Victor Pacheco, but it is a small mountain-dwelling species of the genus Nasuella and is nothing to do with the large rufous species discussed here.
The new rodents are an agouti Dasyprocta, an acouchy Myoprocta and a large paca Agouti (and, yes, we all know how confusing it is that the animals called agoutis are not the same thing as those known scientifically as Agouti. One way round this is to use Cuniculus Brisson, 1762 over Agouti Lacépède, 1799) [image below shows new paca specimen. Note large size and stripes instead of lines of spots as compared with A. paca].
Again, it is likely that we can expect some disagreement as to whether these new forms are good species, or whether they are subspecies or merely local variants. Thorough investigation, including molecular work, field study and morphological comparisons are therefore needed. At the moment Marc’s research on these animals is in its early stages, and for this research to continue, he requires support and funding. More on this later. Speaking of later, check back soon for the next article. It covers multiple new monkeys, and after that we get onto the anteater and the big cat…
Remember also to visit Marc’s excellent site.
Refs – -
Banguera-Hinestroza, E., Cárdenas, H., Ruiz-Garcia, M., Marmontel, M., Gaitá n, N., Vázquez, R., García-Vallejo, R. 2002. Molecular identification of evolutionary significant units in the Amazon river dolphin Inia sp. (Cetacea: Iniidae). The Journal of Heredity 93, 312-322.
Duarte, J. M. B. & Gianonni, M. L. 1996. A new species of deer in Brazil (Mazama bororo). Deer Specialist Group Newsletter 13, 3.
Martínez-Aguero, M., Flores-Ramírez, S. & Ruiz-Garcia, M. 2006. First report of major histocompatability complex II loci from the Amazon pink river dolphin (genus Inia). Genetic and Molecular Research 5, 421-431.
Trolle, M. & Emmons, L. H. 2004. A record of a dwarf brocket from Madre de Dios, Peru. Deer Specialist Group Newsletter 19, 2-5.
Wright, D. B. 1998. Tayassuidae. In Janis, C. M., Scott, K. M. & Jacobs, L. L. (eds) Evolution of Tertiary Mammals of North America. Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals. Cambridge University Press, pp. 389-401.