Colin G. Menter1
1Department of Anthropology and Development Studies, University of Johannesburg, Johannesburg, South Africa
PO Box 524, Auckland Park 2006, South Africa
Received: 05 Oct. 2010
Accepted: 06 Mar. 2011
Published: 12 May 2011
How to cite this article:
Gallagher A, Menter CG. DNH 109: A fragmentary hominin near-proximal ulna from Drimolen,
South Africa. S Afr J Sci. 2011;107(5/6), Art. #456, 4 pages.
© 2011. The Authors. Licensee: OpenJournals Publishing. This work is licensed under the Creative Commons Attribution License.
ISSN: 0038-2353 (print)
ISSN: 1996-7489 (online)
DNH 109: A fragmentary hominin near-proximal ulna from Drimolen, South Africa
In This Research Letter...
• Materials and methods
• Preservation and morphology of DNH 109
• Taxonomic status and age at death
We describe a fragmentary, yet significant, diminutive proximal ulna (DNH 109) from the Lower Pleistocene
deposits of Drimolen, Republic of South Africa. On the basis of observable morphology and available comparative
metrics, DNH 109 is definitively hominin and is the smallest African Plio-Pleistocene australopith ulna yet
recovered. Mediolateral and anteroposterior dimensions of the proximal diaphysis immediately distal to the
m. brachialis sulcus in DNH 109 yield an elliptical area (π/4 *m-l*a-p) that is smaller than the
A.L. 333-38 Australopithecus afarensis subadult from Hadar. Given the unusually broad mediolateral
anteroposterior diaphyseal proportions distal to the brachialis sulcus, the osseous development of the medial
and lateral borders of the sulcus, and the overall size of the specimen relative to comparative infant,
juvenile, subadult and adult comparative hominid ulnae (Gorilla, Pan and Homo), it is
probable that DNH 109 samples an australopith of probable juvenile age at death. As a result of the
fragmentary state of preservation and absence of association with taxonomically diagnostic craniodental
remains, DNH 109 cannot be provisionally assigned to any particular hominin genus (Paranthropus or Homo)
at present. Nonetheless, DNH 109 increases our known sample of available Plio-Pleistocene subadult early hominin postcrania.
The fossil hominin site of Drimolen, currently dated by faunal correlation to between 2.0 MYA and 1.5 MYA,
has yielded a wealth of craniodental specimens attributed to Paranthropus robustus (n = 60)
and a more modest sample of early Homo (n = 9).1,2,3,4 Most of the Australopithecus,
Paranthropus and early Homo hypodigms from the Cradle of Humankind consist of craniodental specimens
in varying states of preservation.2,3,4,5,6,7,8,9
Postcranial specimens attributed to P. robustusand early Homo are comparably rare
and only three localities – Swartkrans, Kromdraai and Drimolen
– have yielded postcranial specimens that are confidently assigned to these
Morphological and metrical affinities of available postcranial remains have generally failed to reject
the hypothesis that a single locomotor ‘morph’ is represented amongst Lower Pleistocene hominins in South
We describe here a fragmentary, yet potentially important, near-proximal ulna (DNH 109) recovered
from the decalcified sediments in the Main Quarry of Drimolen. DNH 109 was excavated in 1995 from
grid square N199, E203 at a height of -2.00 m to -2.10 m below the Drimolen datum.
Comparative infant, juvenile and subadult samples of Pan (including P. paniscus, n = 53), Gorilla
(n = 29) and Homo (n = 162) and adult samples of P. paniscus (n = 15), P. t. troglodytes
(n = 85), G. g. gorilla (n = 99), H. sapiens (n = 118) and Papio (n = 56)
were measured at the Cleveland Museum of Natural History (USA), Kent State University (USA), the Natural History Museum (USA),
the Powell-Cotton Museum (UK), the University of Dundee (UK), the Royal Museum of Central Africa (Belgium) and the
University of the Witwatersrand (SA). The human postnatal growth series comprised individuals aged 0–9 years
at death, whereas the Pan and Gorilla series included individuals ranging from newborn to adolescent
(prior to epiphyseal fusion). The human sample from the Raymond Dart Collection at the University of the Witwatersrand
included South African individuals of European and African ancestry. Original South African fossils and high resolution
casts of available East African specimens were measured in the School of Anatomical Sciences, University of the
Witwatersrand. Linear dimensions of the proximal ulnar diaphysis were taken at the terminus of the m. brachialis s
ulcus25,26 using Mitutoyo™ digital calipers (Mitutoyo Corporation,
Aurora, IL, USA), accurate to the nearest 0.01 mm. Additional published data for A.L. 438-1, KNM-BK 66,
KNM-ER 803, KNM-WT 15000, KRM and Skhul/Qafzeh were used in the analysis.26,27
Preservation and morphology of DNH 109
DNH 109 is a near-proximal portion of a right diaphysis which is broken distal to the coronoid process (Figure 1).
No proximal articulation is preserved. The specimen is missing the olecranon, trochlear notch, radial notch and
coronoid process. The shaft fragment at its greatest length is 52.6 mm. The break at the proximal end of the specimen
is just below the anterior border of the coronoid process. Inferior to this the ulnar tuberosity and a very small
supinator crest are preserved. The ulnar tuberosity is missing a 1-cm long, narrow flake of bone that would form the
proximomedial border of the rim of the ulnar tuberosity. There are several hairline cracks running longitudinally
through the ulnar tuberosity. The medial rim of the ulnar tuberosity displays a number of small grooves that run
from the medial edge onto the posterolateral surface of the shaft, possibly evidence of taphonomic damage by a
carnivore ‘worrying’ the bone. Some small tooth scores are evident. On the anterior surface of the
bone just proximal to the distal break a nutrient foramen is evident. Whilst the supinator crest is evident, it
is abraded over most of its length.
FIGURE 1: DNH 109 in norma verticalis (a) and norma medialis (b).
As no proximal articulation is preserved there is little morphology that can be discussed, which makes the
taxonomic attribution of this specimen problematic.
DNH 109 is both smaller and less robust than the smallest accepted adult Plio-Pleistocene ulna, A.L. 288-1.
The ulnar tuberosity or area for attachment of m. brachialis is well-defined, proximodistally elongate
and forms an ovoid depression reminiscent of the A. afarensis subadult specimen, A.L.
333-98. The medial (anterior border) and lateral margins of the ulnar tuberosity are less well developed than
in A.L. 288-1. The nutrient foramen in DNH 109 lies inferior to the terminus of the brachialis sulcus and is
slightly medial to the lateral border, as in the A.L. 288-1n,t (A. afarensis) paired left and right ulnae.
The only linear dimensions that can be measured on DNH 109 include the mediolateral and anteroposterior dimensions
of the distal margin of the ulnar tuberosity. The linear dimensions of DNH 109 and its calculated elliptical area
are at the lower size range of the available Plio-Pleistocene specimens, particularly with respect to the
anteroposterior depth (Table 1). Although the supinator crest is slightly abraded, it is clear that it is
very weakly expressed; in relation to the fossil hominin sample, it is one of the more weakly expressed
supinator crests. The lack of development of the supinator crest suggests that the specimen is a subadult
individual. In distal view the shaft is triangular in cross section.
TABLE 1: Linear dimensions (mm) of Plio-Pleistocene hominins in comparison to DNH 109.
Taxonomic status and age at death
The proximal diaphyseal proportions of DNH 109 are consistent with a taxonomic allocation to the Hominini tribe.
The majority of Plio-Pleistocene hominin (Australopithecus and early Homo) ulnae contrast with
Pan, Gorilla and more recent humans (ontogenetic and adult, n = 561) in their broad mediolateral
proximal diaphysis relative to the anteroposterior depth at the terminus of the brachialis
(Figure 2), and this proportion is accentuated in certain individuals, including DNH 109,
assigned to Australopithecus, Paranthropus, and Homo. The mediolateral/anteroposterior
proportions of DNH 109 are almost equivalent to other Plio-Pleistocene African australopiths, yet the
anteroposterior diameter in DNH 109 is absolutely small. Whilst DNH 109 is similar to East African early
Homo (Omo L-40-19, KNM-WT 15000) with respect to its extreme mediolateral/anteroposterior proportions
(Table 1 and Figure 2), it also approaches A.L. 333-38, a putative subadult A. afarensis proximal ulna
from Hadar.32 Stw 113 from Sterkfontein Member 4 (STM 4) falls at the lower extremes of
the A. africanus distribution by virtue of its narrow mediolateral/anteroposterior proximal
diaphyseal proportions (Table 1 and Figure 2), yet clusters with Stw 431, Stw 108, and Stw 390. The
mediolateral/anteroposterior proportions of proximal ulnar diaphyses of African late Pliocene australopiths
and Lower, Middle and early Upper Pleistocene Homo show considerable variation, within and between
genera (A.L. 288-1, Figure 2). As such, no obvious conclusions can be drawn as to the precise taxonomic
affinities of DNH 109. The extreme diminution of DNH 109 relative to comparative infant and juvenile hominid
ulnae (including P. paniscus) and representative Plio-Pleistocene hominin comparatives
(including A.L. 333-38) is consistent with an inference of probable late juvenile or early adolescent age at death.
FIGURE 2: Mediolateral diameter of the ulna proximal diaphysis (UPD m-l) relative to the anteroposterior diameter of the ulna proximal diaphysis (UPD a-p). Both dimensions were taken at the terminus of the brachialis crest (ulnar tuberosity).
DNH 109 is definitively hominin and likely represents one of the youngest (ontogenetically) available
Plio-Pleistocene hominin ulnae. The absolute small size of DNH 109 is primarily a function of the
extremely shallow anteroposterior depth of the proximal diaphysis at the terminus of the m. brachialis
crest. DNH 109 is a potentially important new hominin specimen from Drimolen whose size and proportions may
have significance in interpreting the locomotor adaptations of associated craniodental and postcranial
juvenile specimens such as DIK-1-1 (A. afarensis) and MH 1 (A. sediba) for which accurate
dental developmental age at death estimates are available.33,34
We thank D. Smith and J. Smith, on whose property Drimolen is situated, for permission to conduct the excavation
and for their continued assistance. Dr J. Hailie-Selassie and L. Jellema (Cleveland Museum of Natural History),
Dr C.O. Lovejoy (Kent State University) and Mr M. Harman (Powell-Cotton Museum) provided access to specimens in
their care. Original South African fossils were studied at the University of the Witwatersrand and the Northern
Flagship Institute. Dr B. Zipfel and Ms S. Potze kindly facilitated the measurement of specimens in their care.
The Drimolen excavation is supported by grants to CGM from the National Research Foundation (NRF African Origin
Platform, grant number 65155 and a SA-Italy Cooperation agreement, grant number 65155) and the Leakey Foundation.
AG is supported by an NRF/University of Johannesburg Postdoctoral Research Fellowship. Financial assistance was
also provided by the Ford Foundation and the Faculty of Health Sciences, University of the Witwatersrand.
1. Keyser A. The Drimolen skull: The most complete australopithecine cranium and mandible to date. S Afr J Sci. 2000;96:189–193.
2. Keyser A, Menter CG, Moggi-Cecchi J, Pickering TR, Berger LR. Drimolen: A new hominid-bearing site in Gauteng, South Africa.
S Afr J Sci. 2000;96:193–197.
3. Herries AIR, Curnoe DC, Adams JW. A multi-disciplinary seriation of early Homo and Paranthropus bearing
palaeocaves in southern Africa. Quart Internat. 2009;202:14–28.
4. Moggi-Cecchi J, Menter C, Boccone S, Keyser A. Early hominin dental remains from the Plio-Pleistocene site of Drimolen,
South Africa. J Hum Evol. 2010; 58:374–405.
5. Broom R, Robinson JT, Schepers GWH. Sterkfontein ape men. Mem Transv Mus. 1950; No. 4.
6. Clarke RJ. Early Acheulian with H. habilis at Sterkfontein. In: Tobias PV, editor. Hominid evolution: Past,
present and future. New York: Alan R Liss, 1985; p. 287–298.
7. Clarke RJ. Australopithecus and early Homo in southern Africa. In: Delson E, editor. Ancestors:
The hard evidence. New York: Alan R Liss, 1985; p. 171–177.
8. Lockwood CA, Tobias PV. Morphology and affinities of new hominin cranial remains from member 4 of the Sterkfontein
formation, Gauteng province, South Africa. J Hum Evol. 2002;42:389–450.
9. Moggi-Cecchi J, Grine FE, Tobias PV. Early hominid dental remains from members 4 and 5 of the Sterkfontein
formation (1966–1996 excavations): Catalogue, individual associations, morphological descriptions and initial
metrical analyses. J Hum Evol. 2006;50:239–328.
10. Robinson JT. Early hominid posture and locomotion. Chicago: Chicago University Press; 1972.
11. Clarke RJ, Howell FC, Brain CK. More evidence of an advanced hominid at Swartkrans. Nature. 1970;225:1219–1222.
12. Day MH. A guide to fossil man. London: Cassell; 1986.
13. Wood B, Richmond BG. Human evolution: Taxonomy and paleobiology. J Anat. 2000;196:19–60.
14. Wood B, Lonergan N. The hominin fossil record: Taxa, grades and clades. J Anat. 2008;212:354–376.
15. Day MH. Locomotor features of the lower limb in hominids. In: Zuckerman S, editor. The concepts of human
evolution. Symp Zool Soc Lond. 1973;33:29–51.
16. Day MH. Bipedalism: Pressures, origins and modes. In: Wood BA, Martin LB, Andrews PA, editors. Major topics
in primate and human evolution. Cambridge: Cambridge University Press, 1986; p. 188–202.
17. Day MH, Wood BA. Functional affinities of the Olduvai hominid 8 talus. Man, Second Series. 1968;3:440–455.
18. Oxnard CE. Some African fossil foot bones: A note on the interpolation of fossils into a matrix of extant species. Am J
Phys Anthropol. 1972;37:3–12.
19. Oxnard CE. Uniqueness and diversity in human evolution: Morphometric studies of the australopithecines. Chicago:
Chicago University Press; 1975.
20. Lisowski FP, Albrecht GH, Oxnard CE. African fossil tali: Further multivariate studies. Am J Phys Anthropol.
21. McHenry HM, Corruccini RS. Distal humerus in hominoid evolution. Folia Primatol. 1975;23:227–244.
22. Lague MR, Jungers WL. Morphometric variation in Plio-Pleistocene hominid distal humeri. Am J Phys Anthropol. 1996;101:401–427.
23. Bacon A-M. Principal components analysis of distal humerus shape from Pliocene to recent African hominids:
The contribution of geometric morphometrics. Am J Phys Anthropol. 2000;111:479–488.
24. Menter CG. Hominid distal humeri, proximal radii and proximal ulnae from Sterkfontein, in comparison with the
elbow bones of other Plio-Pleistocene fossil hominids. PhD thesis, Johannesburg, University of the Witwatersrand, 2003.
25. McHenry HM, Corruccini RS, Howell FC. Analysis of an early hominid ulna from the Omo basin, Ethiopia. Am J Phys Anthropol.
26. McHenry HM, Brown CC, McHenry LJ. Fossil hominin ulnae and the forelimb of Paranthropus. Am J Phys Anthropol.
27. Pearson OM. Postcranial morphology and the origins of modern humans. PhD thesis, New York, Stony Brook State University of New York, 1997.
28. Howell FC, Wood BA. Early hominid ulna from the Omo basin, Ethiopia. Nature. 1974;249:174–176.
29. Day MH. Functional interpretations of the morphology of postcranial remains of early African hominids. In: Jolly CJ,
editor. Early hominids of Africa. London: Duckworth, 1978; p. 311–345.
30. Aiello LC, Wood BA, Key C, Lewis M. Morphological and taxonomic affinities of the Olduvai ulna (OH 36). Am J Phys
31. Drapeau MSM, Ward CV, Kimbel WH, Johanson DC, Rak Y. Associated cranial and forelimb remains attributed to
Australopithecus afarensis from Hadar, Ethiopia. J Hum Evol. 2005;48:593–642.
32. Lovejoy CO, Johanson DC, Coppens Y. Hominid upper limb bones recovered from the Hadar formation: 1974–1977
collections. Am J Phys Anthropol. 1982;57:637–649.
33. Alemseged Z, Spoor F, Kimbel WH, et al. A juvenile early hominin skeleton from Dikika, Ethiopia. Nature.
34. Berger LR, de Ruiter DJ, Churchill SE, et al. Australopithecus sediba: A new species of Homo-like
australopith from South Africa. Science. 2010;328:195–204.