UEUHA (Chiwondo)
LOCATION
Uraha Hill, western shore of Lake Malawi, Malawi.
DISCOVERY
Hominid Corridor Research Project, 1991-1992.MATERIAL
UR 501, left and right sides of mandibular corpus,
with partial cheek dentition.
DATING AND STRATIGRAPHIC CONTEXT
Recovered from Unit 3A of the Chiwondo Beds, Uraha
(Betzler and Ring, 1995; Bromage et al., 1995), a time-
aggregated unit that spans the period between about
3.76 and 2.0 Ma. The associated fauna is mixed; but all
elements are compatible with an age of ca. 2.4 Ma for
UR 501, although this estimate remains provisional
(Bromage et al., 1995).ARCHAEOLOGICAL CONTEXT
Early reports to the contrary, no in situ artifacts are
known from the Chiwondo Beds (Juwayeyi and
Betzler, 1995).PREVIOUS DESCRIPTIONS AND ANALYSES
UR 501 was first described by Schrenk et al. in 1993
and at greater length by Bromage et al. in 1995. In
both publications, these authors emphasized similari-
ties between this mandible and those fossils from
East Turkana (notably the mandible KNM-ER 1802)
ascribed to Homo rudolfensis by Wood (1991).Ramirez-Rozzi et al. (1997) pointed out certain
differences in enamel thickness between UR 501 and
the Turkana material, but suggested that these differ-
ences reflected interpopulational variation in Homo
rudoCfensis.MORPHOLOGY
R and L mandibular corpora, lacking upper external
part of symphyseal region and both rami, with R and
LP2-M2, R and LC, and damaged alveoli for both
12s; all teeth very worn and damaged to some extent.
Some of the inferior portion of the midline is missing
externally, but corpora articulate well at midline break.
Piece of RM3 (found subsequently) can be associated
with the specimen.
Corpora appear massive relative to tooth size
and also tall s/i relative to tooth height. Mandible
relatively broad across moderately curved symphy-
seal region, and tooth rows somewhat divergent.
Symphyseal region essentially smooth across and
relatively vertical in profile. Anterior root of ramus
takes origin on both sides well below but level with
M1. As seen on the R, bone thickens posteriorly,
suggesting possible mandibular gutter. Short, mildly
sloping postincisal slope curves gently down into
longer plane that bears genial tubercle at large,
swollen inferior margin. No mylohyoid line. Shallow
depressions on both sides of genial tubercle (sub-
mandibular fossae?). As seen on the R, apparent
digastric fossa extremely shallow, long, and slightly
posteriorly facing.306