Top > African Study Monographs > ASM Supplementary Issue Back Number > No.32 (2005)
STUDY OF THE TERTIARY HOMINOIDS AND THEIR PALAEOENVIRONMENTS IN EAST AFRICA: 7

Edited by Hidemi ISHIDA and Hiroshi TSUJIKAWA


pp. 1-50

The Updated Late Miocene Large Mammal Fauna from Samburu Hills, Northern Kenya

Hiroshi TSUJIKAWA
Graduate School of Science, Kyoto University

ABSTRACT
   The Late Miocene Fauna from the Namurungule Formation, Samburu Hills, Northern Kenya was described by Nakaya (1994) and Nakaya et al. (1984, 1987) based on the 1982 and 1984 collections. Since then, numerous fossils were collected during the 1986, 1998 and 1999 field seasons. The additional large mammal fossil specimens which are described in this paper include Amphicyonidae or Ursidae gen. et sp. indet., Machairodontinae gen. et sp. indet., Felidae gen. et sp. indet., Choerolophodon sp., Deinotherium sp., Pliohyracidae gen. et sp. indet., Hipparion africanum, Paradiceros mukirii, Chilotheridium pattersoni, Nyanzachoerus sp. small (N. cf. devauxi), Nyanzachoerus sp. large, Kenyapotamus coryndoni, Palaeotragus cf. germaini, Boselaphini sp. large (Tragoportax sp.), Boselaphini sp. small (gen. et sp. nov.), Reduncini gen. et sp. indet., Gazella sp. and Bovidae gen. et sp. indet. Choerolophodon sp., Pliohyracidae gen. et sp. indet. and Reduncini gen. et sp. indet. were new discoveries in the Namurungule Formation. Nyanzachoerus sp. small (N. cf. devauxi), Palaeotragus cf. germaini and Boselaphini sp. large (Tragoportax sp.) were revised on the basis of well preserved new material. According to the updated faunal list, the Namurungule Fauna shows strong resemblance to faunas of East African localities of the same period, early Late Miocene (10.5 - 9.0 Ma), but shows strong difference from the faunas of East African localities of the Middle (older than 10.5 Ma) and late Late Miocene (7.0 - 5.5 Ma).

Key Words: Late Miocene; Large mammal fauna; Northern Kenya.

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pp. 51-62

THE PALAEOENVIRONMENT OF SAMBURUPITHECUS KIPTALAMI BASED ON ITS ASSOCIATED FAUNA

Hiroshi TSUJIKAWA
Graduate School of Science, Kyoto University

ABSTRACT
   his paper analyzes the palaeoenvironment of the Late Miocene large hominoid, Samburupithecus kiptalami by using the mammalian faunal assemblages. It is based on the mammal fauna found at the hominoid sites, using the habitat preferences of extant mammals, the probable feeding preferences based on morphology of the teeth, the footprint fauna and the relative abundance of each mammal taxon. The habitat preferences of extant mammals and the probable feeding preferences in relative abundances of each mammal taxon suggest that the Upper Member of the Namurungule Formation is likely to have been open whereas the Lower one is likely to have included both open and wooded components. In fact, the faunal components are different at various places in the lower part of the formation. Near the hominoid bearing site, SH 22, the palaeoenvironment seems to have been more wooded. Several places are likely to have been open environments. The footprints suggest a swampland surrounded by savanna. Samburupithecus kiptalami was likely to have inhabited woodland surrounded by an open environment such as savanna and grassland.

Key Words: Hominoid; Late Miocene; Mammalian fauna; Northern Kenya; Palaeoenvironment.

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pp. 63-78

FLORA AND VEGETATION OF NACHOLA, SAMBURU DISTRICT, NORTHERN KENYA: A STUDY OF VEGETATION IN AN ARID LAND

Haruyuki MAKISHIMA
Graduate School of Science, Kyoto University

ABSTRACT
   Although patchy vegetation of open grassland and closed woodland or forest is often reconstructed as a habitat of early hominids, there are few studies of modern vegetation of this type. Vegetational and floral study in Nachola, northern Kenya aimed to remedy this lack. It appeared to have 160 species, which accords well with treated physiognomical classifications of semi arid open vegetations in northern Kenya. There are two contrasting types of vegetation i.e. riverine forest and grassland. Riverine forest comprises two dominant species and several tree species. Grassland has less biomass and despite its name, grass is rare. Instead, dwarf shrubs of Labiatae dominate the surface of the land. Riverine forest in Nachola has two major species, both producing fruits edible to frugivorous mammals, Ficus sycomorus and Acacia tortilis ssp. spirocarpa. Fruit production is suggested to be greater in F. sycomorus. Possibility of early hominid habitats should be discussed based on such an analysis of modern equivalents.

Key Words: Arid land; Flora; Fruit; Pliocene hominids; Riverine forest; Vegetation.

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pp. 79-86

FICUS SYCOMORUS FRUIT PRODUCTION IN A SEMI ARID LAND IN NORTHERN KENYA: IMPLICATIONS FOR UNDERSTANDING A POSSIBLE FOOD RESOURCE OF EARLY HOMINIDS

Haruyuki MAKISHIMA
Graduate School of Science, Kyoto University

ABSTRACT
   Food production of riverine forest in semi arid land, or patchy vegetation in northern Kenya is much needed for discussing the habitat of early hominids. This study aims to estimate the fruit production of Ficus sycomorus along the Baragoi River in Nachola and Baragoi, northern Kenya, possible source for the Pliocene australopithecines. As the largest fruit producer in the forest, the population of F. sycomorus in this riverine forest is counted and the Basal Area of all individuals measured. The number of fruits and their weights are also measured. The total production can be estimated to know the carrying capacity of this forest. The energy yielded by F. sycomorus of this population calculated is at least 74,500 kcal per day. This amount of energy suggests enough for a small group of early hominids during the period of food scarcity.

Key Words: Carrying capacity; Ficus sycomorus ; Fruit production; Pliocene hominid; Riverine forest.

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