Cretaceous Carabidae (Coleoptera) from Orapa, Botswana
Date
1990, 2015
Authors
McKay, Ian James
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Abstract
A fauna of mid-Cretaceous Carabidae (Coleoptera), recovered
from Orapa Diamond mine, Botswana is described. The
carabids are similar to extant forms and include: the first
record of a fossil of the subfamily Promecognathinae,
Palaeoaxinidium orapensis (gen. et sp. n o v . ); the earliest
record of a member of the Scaritinae; and ten specimens
which are placed tentatively in the subfamilies Siagoninae
(two specimens), Pterostichinae (three specimens),
Anchomeninae (one specimen), and Harpalinae (four specimens);
in addition two specimens cannot be placed in any
particular subfamily.
The manner of preservation of the fossils is described, and
a taphonomic analysis of the site is attempted. The exact
age of the sediments is discussed, and a palaeoenvironment
is inferred from a study of the carabids, the rest of the
fossil fauna, and the sediments.
This fauna of carabids lived in a well-wooded crater formed
by the eruption of a kimberlite. The climate of the time
was seasonal, warm, and intermediate between tropical and
temperate extremes.
The morphological conservatism of the promecogna thine, and
the apparent conservatism of the way of life of members of
this group, provides support for the punctuated equilibrium
pattern of evolution.
Description
Thesis (Ph.D.)--University of the Witwatersrand, Faculty of Science, 1990.