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Objectives: The aim of this study is to introduce and systematically assess a new assemblage of colobine fossils (n = 360) recovered from Late Pleistocene (ca. 100,000 years ago) sediments in the Middle Awash research area, Afar Rift, Ethiopia. Materials and Methods: We describe the colobine fossils relative to extant colobine taxa and Middle Pleistocene fossil samples from "Andalee" and Asbole, Ethiopia using linear dental, cranial, and postcranial metrics, as well as qualitative features. We also document the ontogenetic and sex profiles of this sample. Results: Based on morphological affinities to extant and fossil Colobus, we refer these 360 individuals to Colobus cf. guereza. The majority of the individuals (76%) fall into young‐ and middle‐adult age categories. Females are slightly better represented than males, although the majority of individuals (84%) could not be assigned to sex. Discussion: Details of the last half million years of Colobus morphological evolution have remained obscured by a sparse fossil record. The newly recovered, prepared, and curated fossils described herein add significantly to the record of this group. Several morphologies seen in these new fossils fall between the Asbole Colobus sample and extant Colobus guereza, suggesting an ancestral‐descendant phyletic relationship among the three time‐successive samples. The populational variation documented among these samples indicates that the distinctive pattern of sexual dimorphism observed in C. guereza had evolved by 100 ka. [ABSTRACT FROM AUTHOR]

Objectives: The goals of this study were to describe and interpret two new fossil assemblages of cercopithecin monkeys (n = 328), one from the Faro Daba beds (ca. 100,000 years) and the other one from the Chai Baro beds (>158,000 years old), in the Afar Rift of Ethiopia. Materials and Methods: We describe the two assemblages and compare them to extant cercopithecin species and the smaller fossil assemblage from Asbole, Ethiopia (ca. 600 ka). We use a population‐based approach to the taxonomy given the unusually large number of specimens. Craniodental and postcranial anatomy are presented. Evidence of locomotor habitus is described and evaluated in a framework of hybridization and postcranial plasticity. Results: We attribute all cercopithecin specimens from both beds to cf. Chlorocebus and conclude that the Faro Daba and Chai Baro assemblages likely sample single species at each time horizon. Subtle differences between the two assemblages, mostly in postcranial morphology, are insufficient to justify separation at the species level. Discussion: The large sample sizes and unique preservational aspects of these two assemblages open a new window into the recent evolution of guenons. Our data indicate that these fossil populations may be ancestral to the cercopithecins currently living in the Afar region of Ethiopia. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study is to assess a new assemblage of papionin fossils (n = 143) recovered from later Pleistocene sediments in the Middle Awash study area in the Afar Rift of Ethiopia. Materials and Methods: We collected metric and qualitative data to compare the craniodental and postcranial anatomy of the papionin fossils with subspecies of modern Papio hamadryas and with Plio‐Pleistocene African papionins. We also estimated sex and ontogenetic age. Results: The new fossils fit well within the range of morphological variation observed for extant P. hamadryas, overlapping most closely in dental size and proportions with the P. h. cynocephalus individuals in our extant samples, and well within the ranges of P. h. anubis and P. h. hamadryas. The considerable overlap in craniodental anatomy with multiple subspecies precludes subspecific diagnosis. We therefore referred 143 individuals to P. hamadryas ssp. The majority of the individuals assessed for ontogenetic age fell into middle‐ and old‐adult age categories based on the degree of dental wear. Males (26%) were better represented than females (12%) among individuals preserving the canine‐premolar honing complex. Discussion: These new near‐modern P. hamadryas fossils provide a window into population‐level variation in the later Pleistocene. Our findings echo previous suggestions from genomic studies that the papionin family tree may have included a ghost population and provide a basis for future testing of hypotheses regarding hybridization in the recent evolutionary history of this taxon. [ABSTRACT FROM AUTHOR]