THE NEW WORLD GENUS STENOMORPHUS DEJEAN (COLEOPTERA: CARABIDAE: HARPALINI): CLASSIFICATION, ALLOMETRY, AND EVOLUTIONARY CONSIDERATIONS

Abstract

AbstractAnalysis of structural features of adults (legs, proportions of prothorax, male genitalia, and ovipositor) establishes the hypothesis that Anisocnemus Chaudoir, Trichopselaphus Chaudoir, and Stenomorphus Dejean comprise a monophyletic assemblage, named the Stenomorphus genus-group, with Anisocnemus the adelphotaxon of Trichopselaphus + Stenomorphus. Analysis of form of median lobe, armature of the internal sac, allometric trends in proportions of the prothorax and hind tibia, and chorological considerations, provide the basis for recognition of six species of Stenomorphus and postulation of their phylogenetic relationships, as follows: S. convexior Notman {[S. penicillatus Darlington + S. sinaloae Darlington] + [S. cubanus Darlington + (S. angustatus Dejean + S. californicus Ménétries)]}. Three monophyletic species-groups are recognized: S. convexior, including S. convexior; S. sinaloae, including S. penicillatus and S. sinaloae; and S. angustatus, including S. cubanus, S. angustatus, and S. californicus. The names Stenomorphus dentifemoratus Chaudoir, 1844 and Stenomorphus alius Darlington, 1936 are synonymized, and S. dentifemoratus Darlington, 1936 (not Chaudoir) is renamed S. darlingtoni. Morphometric and chorological features provide evidence for subspecific recognition, each taxon representing a new combination: for S. angustatus, S. a. angustatus, S. a. braziliensis Darlington, and S. a. dentifemoratus Chaudoir; for S. californicus, S. c. californicus, S. c. rufipes LeConte, S. c. manni Darlington, and S. c. darlingtoni Ball and Shpeley. Evolutionary trends postulated include development of allometry with respect to form of the prothorax and hind tibiae, correlated with sexual dimorphism. Driving forces are postulated to be associated with sexual selection and burrowing. The geographical history of Stenomorphus is reconstructed as follows, using the reconstructed phylogeny and chorological affinities interpreted against a background of geological and climatic events in Middle America, during the Late Cretaceous, and Tertiary and Quaternary Epochs: isolation in Middle America from its South American adelphotaxon of the ancestral stock of Stenomorphus; specialization for life in drier tropical forests and savannas; isolation and differentiation of taxa in response to cyclical climatic changes and mountain building; and over-water dispersal to, and isolation and differentiation in, the Greater Antilles. A key, figures of diagnostic features, descriptions of structural features and of geographical ranges (supplemented with maps) provide means of recognition of taxa.