Where: Djibouti (11.6° N, 42.4° E: paleocoordinates 11.6° N, 42.4° E)

• coordinate stated in text

• outcrop-level geographic resolution

When: Middle Pleistocene (0.8 - 0.1 Ma)

• The sediments clearly belong to what Roger et al. (1974) and Thomas et al. (1984) called 'Formation 1', which also includes their localities MW 196, 197, 201, and 207, defined by Marc Weidmann (in litt.) in the area of Giba Bouyyi. This formation corresponds to what Stieltjes (1980) mapped as Plio-Pleistocene clays and conglomerates; it is well exposed on steep slopes below hill 399 (Stieltjes, 1980). It rests upon basalts dated to c. 2.35 Ma (Roger et al., 1974, 1975), and is disconformably overlain by a basalt for which Tapponnier and Varet (1974) provided, without details, an age of at most 0.8 Ma. In spite of the limited number of specimens, the evolutionary stage reached by the AssalW Theropithecus leaves little doubt as to its age. It is certainly younger than the Okote Member of Koobi Fora or Olduvai upper bed II; the sample size for the other sites is low, but the fact that the M2 was certainly larger than that of all other specimens, including Asbole, the Dawaitoli Fm, and Makuyuni, all dated to c. 0.6-0.7 Ma, strongly suggests that its age is closer to 0.5 Ma than to 1 Ma. As mentioned above, the basalts capping the sedimentary exposures of AssalW were first reported to date from c. 0.8 Ma (Tapponnier and Varet, 1974; Roger et al., 1974) but this date must be regarded with caution as no detail has been published on the methods and geographic location of the samples. Zumbo et al. (1995) attempted to date the lava flows of Assal rift margins (Dat'Ali basalts and Adayle trachyte) by 40Ar/39Ar, but only one of them provided a plateau age of 0.88 Ma; the others were more difficult to interpret, with minimum age estimates of c. 0.4 and 0.5 Ma. So, on the whole there is no major discrepancy between the evolutionary stage of Theropithecus and the radiochronologic ages, but we believe that an Early Pleistocene age is unlikely, and thus that an age distinctly earlier than 0.8 Ma can be excluded.

• group of beds-level stratigraphic resolution

Environment/lithology: terrestrial; siliciclastic sediments

Size class: macrofossils

Collected by L. de Bonis, D. Geraads, F. Rocroy, J. Sudre in 1986

• Repository: PALEVOPRIM Laboratory, University of Poitiers

Primary reference: D. Geraads and L. de Bonis. 2020. First record of Theropithecus (Cercopithecidae) from the Republic of Djibouti. Journal of Human Evolution 138(102686) [M. Clapham/M. Clapham/M. Clapham]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 209750: authorized by Matthew Clapham, entered by Matthew Clapham on 14.05.2020

Creative Commons license: CC BY (attribution)