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Abstract

Blackburnia gastrellariformis sp. n., is described from East Molokai, Hawaii. Based on cladistic parsimony analysis of adult characters, the species is hypothesized to be most closely related to B. komohana Liebherr & Zimmerman of West Maui, with these two species comprising the adelphotaxon to the East Maui species pair, B. haleakala Liebherr & Zimmerman + B. putealis (Blackburn). Previous reconciled tree analysis for the Hawaiian Blackburnia radiation conducted before discovery of B. gastrellariformis found a general pattern in which Molokai and West Maui were hypothesized as sister-areas to the exclusion of the East Maui volcano, Haleakala, though the less common, incongruent area relationship of (Molokai (West Maui + East Maui) was also represented in the taxon-area cladogram. In the present reconciled tree analysis, the closest hypothesized relationship of B. gastrellariformis and a West Maui species corroborates the more common pattern by replacing items of error in the previous analysis with the newly discovered species. Elevational habitat shifts are invoked to explain the occurrence of numerous sister-species pairs in Molokai and West Maui, currently separated by the Pailolo Channel, relative to species occupying Haleakala.

In: Insect Systematics & Evolution

The Papuan endemic genus Dobodura Darlington is taxonomically revised, with five newly described species — Dobodura alildablldooya sp. n., D. hexaspina sp. n., D. obtusa sp. n., D. svensoni sp. n., and D. toxopei sp. n. — complementing the type species, D. armata Darlington. The sympatric Dobodura alildablldooya and D. svensoni are described from Chimbu Province, Papua New Guinea. Known distributions of the other three new species are: D. hexaspina, Madang Province, P.N.G.; D. obtusa, Olsobip, Fly River, Western Province, P.N.G.; and D. toxopei, Bernhard Camp, Papua, Indonesia. Dobodura is the sole precinctive Papuan genus in an Australian-Papuan clade also including Clarencia Sloane, Dicraspeda Chaudoir, and Eudalia Laporte. Phylogenetic analysis of Dobodura places its known earliest divergence event on the northern New Guinea margin of the Australian craton. Later divergence events result in species occupying island-arc terranes progressively incorporated into present-day northern New Guinea, commencing in the Miocene.

In: Tijdschrift voor Entomologie

Abstract

Mecyclothorax palikea, sp.n. is described from the vicinity of Palikea, southern Waianae Range, Oahu, HI, USA and is assigned to Britton's Mecyclothorax flavomarginatus species group. Cladistic analysis, based on 20 morphological characters and including several outgroup taxa, places Mecyclothorax impunctatus Liebherr of Molokai as adelphotaxon to the other eight species of the group, with subsequent speciation events successively isolating M. sharpi Britton of West Maui versus a clade of seven Oahu species. Phylogenetic relationships among the Oahu clade species posit three historical speciation events vicariating ancestors on the western Waianae and eastern Koolau Ranges. Mecyclothorax palikea is placed as adelphotaxon to M. carteri (Perkins), a species allopatrically distributed to the north in the Waianae, corroborating existence of southern and northern areas of endemism within the Waianae Range. Relative ages of the respective volcanoes housing M. flavomarginatus group species — Waianae (3.7 million years ago), Koolau (2.6 million years ago), Eastern Molokai (1.8 million years ago), West Maui (1.3 million years ago)—imply that ancestral occupation of Oahu by this group occurred subsequent to completion of the shield building phases of Oahu's two volcanoes, Waianae and Koolau. Diversification within the group on Oahu was associated with vicariance events that occurred within a terrestrial environment. Whereas all four species of the M. flavomarginatus group occupying Waianae Range habitats have been observed recently in nature, collection of M. flavomarginatus in 1906 represents the most recent record for any M. flavomarginatus group species in the Koolau Range, indicating the importance of conserving appropriate Waianae Range habitats in order to preserve representative biodiversity in this species group.

In: Insect Systematics & Evolution

Western Australian populations of Mecyclothorax punctipennis (MacLeay) exhibit chiral polymorphism for male genitalic asymmetry. The plesiomorphic genitalic enantiomorph, wherein the male aedeagal median lobe is left side superior when retracted in the abdomen, is rotated 180° to a right side superior position in 23% of males from Western Australia. Conversely, population samples from eastern Australia are monomorphic for the plesiomorphic left side superior condition. Western Australian population samples are significantly heterogeneous for the percentages of chirally reversed males, with right side superior frequencies ranging 0–58%. Conversely, asymmetry of the M. punctipennis female reproductive tract, wherein the apex of the bursa copulatrix is distally expanded toward the right side of the individual, is shown to be monomorphic within the species. Based on the vast disparity in frequencies of left versus right enantiomorphs among populations of Western Australian M. punctipennis, we hypothesize that population demographic factors related to very small population size and differential gene sampling via genetic drift could interact to establish populations fixed for the novel form. When such chiral genitalic substitutions are coupled with speciation, subsequent diversification stemming from that common ancestor would result in monophyletic lineages characterized by genitalic inversion. This hypothesis is corroborated by the sporadic occurrences of individual males with chirally inverted genitalia throughout the Carabidae, and the known occurrence of eight carabid taxa — individual species to diverse lineages — that are monomorphically characterized by male genitalic inversion.

In: Insect Systematics & Evolution