- Comparative Anatomy
assistant to L.S.B. Leakey
Olduvai Gorge, Tanzania
OH 8 is comprised of all the left tarsal and metatarsal bones, but no phalanges are present. All the tarsals, except for the calcaneus, are completely preserved—only the distal end of the calcaneus is present. The metatarsals are missing their distal heads, and Metatarsal V is also missing the styloid process.
The absence of the metatarsal heads is the basis for controversy regarding the specimen’s age. While some argue the absence of the metatarsal heads is due to carnivorous activities, others suggest this could represent unfused epiphyseal surfaces, making OH 8 a subadult. Some even suspected that a juvenile mandible, OH 7, found 5 m from OH 8 and within the same strata, may belong to the same individual as that of OH 8.
The assignment of OH 8 to Homo habilis is also controversial, as some believe the foot morphology is clearly Homo, while others believe it should be assigned to Australopithecus. For example, OH 8 talar morphology is "squat and foreshortened" like that of a quadruped. On the other hand, recent studies2 suggest that the foot exhibits morphology indicative of longitudinal arch that is more like Homo.
There are many affinities that parallel OH 8 with modern humans as well. The foot’s metatarsal robusticity pattern is similar to modern humans1. Typical modern human robusticity pattern is 1>5>4>3>2, with a small percentage as 1>5>3>4>2. This is either identical or similar to OH 8 which is 1>5>3>4>2. OH 8 is also similar to humans in relative foot length (substituting OH 35 tibia for the missing OH 8 tibia). There is also evidence within the calcaeocuboid joint that indicates a mid-tarsal break during the stance phase would have been prohibited2. Furthermore, it is suspected that the hallux was adducted, like in modern humans.
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