Cyphocoleus Chaudoir (Coleoptera, Carabidae, Odacanthini): descriptive taxonomy, phylogenetic relationships, and the Cenozoic history of New Caledonia

Abstract

The precinctive New Caledonian genus Cyphocoleus Chaudoir is revised with 22 species recognized, 12 newly described: C. lissus sp. n., C. prolixus sp. n., C. parovicollis sp. n., C. burwelli sp. n., C. angustatus sp. n., C. monteithi sp. n., C. fasciatus sp. n., C. lescheni Liebherr & Will, sp. n., C. cordatus sp. n., C. bourailensis sp. n., C. subulatus sp. n., and C. iledespinsensis sp. n. Atongolium Park & Will is found to be a junior synonym of Cyphocoleus, with its two species recombined as C. mirabilis comb. n. and C. moorei comb. n. Results of a survey of Harpalinae Bonelli place Cyphocoleus as a member of Odacanthini based on synapomorphies of the eighth abdominal tergite and the female spermathecal assembly. Cyphocoleus shares with five other generic-level taxa – Homethes Newman, Aeolodermus Andrewes, Stenocheila Laporte, Quammenis Erwin and Diplacanthogaster Liebke – a single-segmented maxillary galea that is appressed to the outer margin of the maxillary lacinia. These six generic-level taxa are newly classified as members of subtribe Homethina subtrib. n. (type genus Homethes). Cladistic analysis including 79 taxa and utilizing 119 morphological characters supports division of Odacanthini into four monophyletic subtribes: 1, Actenonycina (Actenonyx White); 2, Homethina; 3, Pentagonicina (Pentagonica Dana, Parascopodes Darlington, Scopodes Erichson); and 4, Odacanthina (24 genera in this analysis monophyletically defined by Lasiocera Dejean and its adelphotaxon). These subtribes are phylogenetically arranged as: (Actenonycina (Homethina (Pentagonicina + Odacanthina). Area relationships defined within Homethina – (New Caledonia (Australia (South America + Central America))) – support the origin of New Caledonian Cyphocoleus prior to amphiantarctic vicariance between South America and Australia. Consistent with previous molecular dating of 100–105 Ma for the origin of Odacanthini, a general vicariance-based hypothesis proposes that New Zealandian Actenonyx and New Caledonian Cyphocoleus were emplaced on Zealandia prior to the completion of rifting between Zealandia and Australia during Late Cretaceous, and that both fragments of Zealandia remained subaerial throughout the Cenozoic. Alternatively, under a very specific time-constrained biogeographic hypothesis ladened with an added assumption of dispersal, the ancestor of Cyphocoleus could have colonized New Caledonia during a 2–5 Ma period after its proposed subaerial reemergence at 37 Ma. A clade within Cyphocoleus synapomorphously exhibits an environmental patina: a varnish-like coating to the dorsal body surface that is hypothesized to enable crypsis of the adult beetle. Several specializations of elytral setae are also synapomorphies of this clade, suggesting evolutionary association of the patina and the setal specializations.