Descriptive Catalogue of Pliocene cercopithecoid Fossils (Primates, Mammalia) from the Humpata Plateau, Angola

Cercopithecid fossils were first collected from the Plio-Pleistocene karstic infillings of the Humpata Plateau, southern Angola, in the 1940’s. Further collections were made during the 1950s by F. Mouta and by J. Camarate-França, but only a few of the more complete cranial specimens were published by C. Arambourg and F. Mouta and later revised by E. Delson, C. Gilbert and other researchers. In the collections made by Camarate-França, there are more than 100 isolated teeth and many postcranial elements that have never been described, possibly because of the untimely death of the latter researcher who was undertaking his thesis studies on them. The materials are curated by the Museum of Natural History and Science of the University of Lisbon, and the collection is currently deposited at Centre for Archaeology (UNIARQ). There are several cercopithecid specimens curated at the Museu Regional de Huila, in Lubango, Angola, but they have not been freed from their breccia matrix and remain unstudied. Additional monkey specimens were collected from the region in 1989 and 1990 by the Angola Palaeontology Expedition, some of which were published by N. Jablonski, with subsequent revisions by E Delson, C. Gilbert and other researchers.

The present publication illustrates and provides succinct descriptions of many of the accessible cercopithecid dentognathic fossils from the Quaternary of Angola, and provides measurements and taxonomic identifications, so that researchers can access the data for their own studies.

The currently available collections of fossils from Angola indicate that there are at least three, possibly four, geochronological assemblages in the region, one from Tchiua which is basal to middle Pliocene in age, the second from Cangalongue which exhibits somewhat younger affinities within the Pliocene (Fig. 5), the third from Malola, of Late Pliocene age, and a fourth assemblage, with few if any primate fossils in association with Middle Stone Age tools at Leba Cave (not treated in this catalogue, but mentioned briefly by Gautier, 1995) but most of the primate material listed by the latter author is from Tchiua, not the Leba Cave.

The Tchiua cercopithecid assemblage comprises three taxa: one large species of colobine and two papionines, one related to mandrills or baboons, the other to geladas, whereas the Cangalongue assemblage currently consists of a single small species of Theropithecus. The cercopithecid fossils from Ufefua and Malola are unidentifiable fragments. The possible presence of a mandrill-like cercopithecid in the middle Pliocene of Angola is potentially of great interest, not only because it would be among the earliest known members of the clade, but also because it occurs well outside the present-day range of distribution of extant mandrills.

Key Words: Colobines, Mandrills, Baboons, Geladas, Pliocene, Biogeography, Biostratigraphy, Southern Africa

Introduction 8
Historical Perspective 8
Archives Concerning the Discovery Context of Tchiua Fossils 9
Provenience Issues 10
Toponomastics 10
Abbreviations 10
Material and Methods 11
Dental Nomenclature 11
Geological Context, Location and Age 12
Humpata Fossil Cercopithecidae 16

Descriptive Catalogue 20
Family Cercopithecidae Gray, 1821  20
Subfamily Colobinae Jerdon, 1867 20
Genus Kuseracolobus Frost, 2001 21
Species Kuseracolobus hafu Hlusko, 2006 21
Subfamily Cercopithecinae Gray, 1821 30
Genus cf Mandrillus Ritgen, 1824 32
Species cf Mandrillus sp. indet. 32
Genus Omopithecus Delson 1993 42
Species Omopithecus baringensis (Leakey, 1969) 42
Genus Theropithecus Geoffroy, 1843 64
Species Theropithecus oswaldi serengetensis (Dietrich, 1942) 64

Context and Age 66
Postcranial skeletal Material from Tchiua 67
Taphonomic Considerations  68

Conclusions 68

Acknowledgements 69

Funding 69

References 70

The aim of this paper is to document and illustrate the dentognathic remains of Late Neogene fossil cercopithecoids from the Humpata Plateau, southern Angola. The fossils range in age from early to middle Pliocene and Pleistocene, and the assemblages from the different localities are radically different from each other. The older assemblage from Tchiua contains abundant remains of three taxa (a large species of colobine and two papionines; one related to mandrills or baboons and the other to geladas) whereas the slightly younger assemblage from Cangalongue consists of a mandible attributed to Theropithecus and a few undescribed specimens stored in the MRH, Lubango, that are still embedded in their sediment matrix. There are a few monkey specimens from Ufefua 2 and Malola, but they are essentially unidentifiable. However, these two localities have the potential to yield additional specimens.