Abstract:
The early Pliocene interval of the Apak Member at Lothagam, Kenya, documents significant
faunal turnover. During this time, wooded savannas and savanna woodlands expanded in eastern
Africa, and elephants consequently evolved to better adapt to grazing. It is also the time of the
first appearance of the hominin Australopithecus, many modern antelope tribes, new horses,
hippos, and pigs. Proboscidean species previously identified from the Apak Member include
Deinotherium bozasi, Anancus kenyensis, Stegotetrabelodon orbus, cf. Elephas ekorensis? aff.
Loxodonta, Loxodonta exoptata, and several unidentified elephantids. This study describes new
proboscidean specimens and compiles a database of proboscideans from the Apak Member at
Lothagam. The study focuses on measurements and morphological descriptions of 14 new and
12 previously studied specimens housed at the National Museums of Kenya. Essential features
studied include relative height of the crown (hypsodonty index), which is important for grazing
animals, and number of molar plates, which increase in more advanced proboscideans. The study
further compares the new database, with that of late Miocene Lothagam proboscideans and
proboscidean assemblages from nearby sites of similar age, particularly those from other sites in
or near Turkana Basin including Kanapoi, Ileret, and South Turkwel. The objectives were to
increase our knowledge of the transition from archaic to more advanced proboscideans in Africa
and proboscidean cohorts' role in shaping ecosystem changes. The results meaningfully revise
upwards, the taxonomic composition of proboscideans in the Apak Member, and reveal a
complex relay of primitive to more derived elephants during the early Pliocene, that documents
the adaptive response to increased competition among mammals for grazing resources
