New primate genus from the Miocene of Argentina

Abstract

Killikaike blakei is a new genus and species of anthropoid from the late Early Miocene of southeastern Argentina based on the most pristine fossil platyrrhine skull and dentition known so far. It is part of the New World platyrrhine clade (Family Cebidae; Subfamily Cebinae) including modern squirrel (Saimiri) and capuchin monkeys (Cebus) and their fossil relatives known from Early to Middle Miocene and subrecent periods. Living cebines are relatively largebrained, adroit predatory foragers and live within complex social groups, and wild capuchins exhibit a wide range of behaviors associated with enhanced intelligence. We show that K. blakei lacks diagnostic derived characteristics of the lower face and premolar dentition that are shared by modern cebines, but its strongly vaulted frontal bone and capacious anterior cranial fossa indicate the early evolution of an enlarged forebrain.Miocene ͉ Paleoprimatology ͉ Patagonia ͉ Platyrrhini ͉ Cebinae

Estimating body mass in New World “monkeys” (Platyrrhini, Primates), with a consideration of the Miocene platyrrhine, Chilecebus carrascoensis

“…Martin (1990) analyzed 25 living haplorhines (Anthropoidea plus tarsiers), demonstrating that living anthropoids are large-brained compared to strepsirrhine primates relative to a ''basal insectivores'' reference frame. Tejedor et al (2006) noted that the ,16.4 Ma cebine platyrrhine Killikaike blakei possesses a strongly vaulted frontal and large anterior cranial fossa, suggesting an expanded forebrain early in cebine evolutionary history. Only the anterior portion of the skull is preserved, thus a total brain volume cannot be estimated, although enlarged forebrains do correlate with relatively larger brains in cebines, suggesting that the brain of Killikaike was likely quite large.…”

Oldest known cranium of a juvenile New World monkey (Early Miocene, Patagonia, Argentina): Implications for the taxonomy and the molar eruption pattern of early platyrrhines

“…Cranial comparisons MPM-PV 3505 is, in most respects, very similar to CORD-PZ 1130 from Puesto Estancia La Costa (Tauber, 1991), MPM-PV 5000 from Killik Aike Norte (Tejedor et al, 2006), and to other specimens of Homunculus from PLC and KAN (Kay et al, 2012). All crania from the SCF are very similar in the proportions and arrangement of the cranial bones, the shape and orientation of the orbits and nasal aperture, and the size and position of the facial foramina.…”

“…However, the lingual cingulum in MPM-PV 1607 (the referred specimen from KAN) is at least as well developed as in MPM-PV 3505. MPM-PV 5000 and MPM-PV 3505 lack a hypocone on M 3 , but one appears to be present on MPM-PV 1607 (Tejedor et al, 2006, Fig. 1F).…”

“…In combination, the dental and cranial comparisons allow us to evaluate the taxonomic distinctness of the two taxa. Such an evaluation is of particular importance because of recent claims that one species (H. patagonicus) represents a basal member of the extant family Pitheciidae (Tejedor and Rosenberger, 2008), and that the other (K. blakei) is an early representative of the extant family Cebidae (Tejedor et al, 2006;Rosenberger, 2011).…”

“…Because the original holotype of H. patagonicus is lost, Tejedor and Rosenberger (2008) designated a neotype for this taxon. Slightly before that, another SCF primate taxon, Killikaike blakei Tejedor et al, 2006, was erected. This introduces certain practical difficulties: the neotype of H. patagonicus is a mandible but the holotype of K. blakei (and a single referred specimen) consists of upper teeth, a palate, and face.…”