Arrival order and release from competition does not explain why haplochromine cichlids radiated in Lake Victoria.

The frequent occurrence of adaptive radiations on oceanic islands and in lakes is often attributed to ecological opportunity resulting from release from competition where arrival order among lineages predicts which lineage radiates. This occurs when the lineage that arrives first expands its niche breadth and diversifies into a set of ecological specialists with associated monopolization of the resources. Later-arriving species do not experience ecological opportunity and do not radiate.

Kanapoi revisited: Paleoecological and biogeographical inferences from the fossil fish.

Fish fossils were recovered from three different depositional contexts at the Pliocene Kanapoi site to: 1) test the assumption that habitat and ecology of modern fish taxa can predict habitat and ecology of fossil taxa; 2) reconstruct the lake and river environments in the Kanapoi Formation, with reference to fish fossils from the nearby Lothagam site deposits; and 3) investigate biogeographical inferences from the fossils. We compare the Kanapoi fish taxa and their depositional environments with the taxa and environments in modern Lake Turkana, and with another Plio-Pleistocene fauna from the eastern Turkana Basin. Taphonomic caveats are discussed.

Paleoecology of the Serengeti during the Oldowan-Acheulean transition at Olduvai Gorge, Tanzania: The mammal and fish evidence.

Eight years of excavation work by the Olduvai Geochronology and Archaeology Project (OGAP) has produced a rich vertebrate fauna from several sites within Bed II, Olduvai Gorge, Tanzania. Study of these as well as recently re-organized collections from Mary Leakey's 1972 HWK EE excavations here provides a synthetic view of the faunal community of Olduvai during Middle Bed II at ∼1.7-1.

Environmental change and hominin exploitation of C4-based resources in wetland/savanna mosaics.

Eastern and southern Africa experienced ongoing climatic and tectonic instability in the Plio-Pleistocene, alongside declining forests and expanding grasslands. Most known hominin genera (Australopithecus spp., Kenyanthropus, Paranthropus spp.

The geological, isotopic, botanical, invertebrate, and lower vertebrate surroundings of Ardipithecus ramidus.

Sediments containing Ardipithecus ramidus were deposited 4.4 million years ago on an alluvial floodplain in Ethiopia's western Afar rift. The Lower Aramis Member hominid-bearing unit, now exposed across a > 9-kilometer structural arc, is sandwiched between two volcanic tuffs that have nearly identical 40Ar/39Ar ages.