n African Entomology - Diversity of Hymenoptera and other insects in the Late Cretaceous (Turonian) deposits at Orapa, Botswana : a preliminary review
|Article Title||Diversity of Hymenoptera and other insects in the Late Cretaceous (Turonian) deposits at Orapa, Botswana : a preliminary review|
|© Publisher:||Entomological Society of South Africa (ESSA)|
|Author||D.J. Brothers and A.P. Rasnitsyn|
|Publication Date||Sep 2003|
|Pages||221 - 226|
|Keyword(s)||Fossil assemblages and Fossils|
The kimberlitic eruption that formed the crater at Orapa occurred about 91 Mya, and its fossiliferous sediments were deposited shortly thereafter. The pieces of rock from Orapa which contain insect fossils, approximately 2000 currently housed in the Bernard Price Institute of Palaeontology at the University of the Witwatersrand and about 220 in the National Museum of Botswana in Gaborone, were screened for Hymenoptera, and all arthropods on the 68 pieces so selected were identified to the lowest level possible. After adjusting for the prior selection of Hymenoptera, the ordinal composition of the arthropods was calculated. The major components, based on number of specimens, are : Coleoptera (29 %), Homoptera (18 %), Blattodea (17 %), Diptera (13 %), Thysanoptera (7 %), and Hymenoptera and Orthoptera (6 % each). The major components of the 108 specimens (at least 68 species) of Hymenoptera are approximately: Chalcidoidea (20 %), Formicidae and Sphecidae s.l. (12 % each), Megalyridae, Braconidae and Bethylidae (9 % each), Scelionidae (7 %), Gasteruptiidae (6 %) and Ichneumonidae (5 %). Comparison with hymenopteran assemblages from other Cretaceous localities, shows that the Orapa assemblage conforms with the Armaniid Kind, but with an unusually high number of Chalcidoidea (exceeding Scelionidae), and is essentially concordant with expectations based on other Turonian assemblages of Hymenoptera.
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