Omophron and the origin of Hydradephaga (Insecta: Coleoptera: Adephaga)

The enigmatic genus Omophron is placed cladistically based upon a reanalysis of coxal cavity characters. Omophron is hypothesized to be the sister group of Trachypachini plus Hydradephaga. This result agrees with a previous analysis of relationships based upon the sclerites and associated musculatur...

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Bibliographic Details
Published in:Proceedings of the Academy of Natural Sciences of Philadelphia 1985-01, Vol.137 (1), p.182-201
Main Author: Nichols, S.W
Format: Article
Language:English
Subjects:
Amphizoidae
Beetles
Burrowing
Carabidae
CLASIFICACION
CLASSIFICATION
COLEOPTERA
Entomology
EVOLUCION
EVOLUTION
Female animals
Freshwater
Haliplidae
Legs
Notiophilus
Omophron
Septum
Sternum
Taxa
Trachypachus
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Summary:The enigmatic genus Omophron is placed cladistically based upon a reanalysis of coxal cavity characters. Omophron is hypothesized to be the sister group of Trachypachini plus Hydradephaga. This result agrees with a previous analysis of relationships based upon the sclerites and associated musculature of the female egg-laying apparatus studied by Bils. The peculiar morphology of Omophron is judged to be an evolutionary modification for burrowing in sand without the development of fossorial limbs and without the concomitant loss of speed and agility for running over the surface of the ground. Based upon this analysis externally closed procoxal cavities are judged to be plesiomorphic for Adephaga; the Hydradephaga are judged to be highly derived aquatic carabids.
ISSN:0097-3157
1938-5293