Archicorynini Anderson and Marvaldi, 2013

Anderson, Robert S. & Marvaldi, Adriana E., 2013, Finding Unexpected Beetles in Odd Places: Archicorynus kuscheliAnderson and Marvaldi, a New Genus and Species Representing a New Tribe, Archicorynini, of Oxycoryninae (Coleoptera: Belidae) from Nicaragua, The Coleopterists Bulletin 67 (2), pp. 61-71 : 61-71

Tribe Archicorynini Anderson and Marvaldi , new tribe

Type Genus. Archicorynus Anderson and Marvaldi.

Diagnosis. Oxycoryninae characterized by a more ventral rostral insertion (than species in other tribes) not forming a rounded ventral side of head, anterior face of procoxae with suture visible and without protruding apex of trochanter, and by compact antennal clubs comprising tightly joined segments 9–11.

Phylogenetic Position. The monophyly of Archicorynus and the remaining oxycorynines is supported by at least 13 unambiguous synapomorphies (see Fig. 14 ), the clearest being: funicles with second segment subequal in length to first; lateral pronotal margins crenulate; meso- and metatibiae with carinate dorsal margin; tarsi with basal segment very short, shorter than second and almost concealed; hind margin of wings devoid of setae on anal lobe. As the sole representative of Archicorynini , Archicorynus appears to represent the sister-group of all other known Oxycoryninae ( Fig. 14 ). This earliest divergent position is supported by plesiomorphic retention of the rostral insertion on the ventral side of head in lateral view (36-0) and by the anterior face of the procoxae with a visible suture but without the protruding apex of the trochanter (70-0). These characters exclude the genus from a monophyletic clade consisting of all other Oxycoryninae which share the apomorphic conditions of a convex, usually rounded, ventral side of head (36-1-2) and the anterior face of the procoxae with suture obliterated and the trochanteral apex protruding out of the pit (70-1). In addition, the underside of the elytra of Archicorynus in the region opposite to the metacoxae has an odd ‘pocket-like’ ridge ( Fig. 9 ) not seen in other Oxycoryninae . A similar structure was observed in the inner surface of elytra of several Belinae (i.e. Agnesiotis sp. , Rhinotia spp. ) suggesting that this feature might be another plesiomorphic retention of Archicorynus . Besides the morphological evidence presented here, the DNA sequences (from 18S and 28S rRNA and COI markers) already obtained for Archicorynus (A. E. Marvaldi and M. S. Ferrer, unpublished data) also suggest a close relationship of Archicorynus with the other oxycorynines.

Alternative relationships that might be easier to justify by vicariance biogeography are that Archicorynus is the sister taxon to just the New World Oxycoryninae (Oxycorynini) or to a subgroup of these. This hypothesis requires assumption of a reversal in the structure of the trochanter as well as a reversal in the positioning of the rostrum. It is also less consistent with the biological attributes of the taxa as all Oxycorynini are associated with the reproductive structures of various plants, whereas Archicorynus appears to be associated with dead vegetative plant parts, the presumed ancestral habit of the subfamily ( Marvaldi et al. 2006). Thus, while Metrioxenini and Aglycyderini (and Archicorynini ) appear to have retained an association with dead vegetative plant parts, Oxycorynini by contrast shifted their development to reproductive organs, initially retaining an association with conifers but later colonizing cycads and two groups of rootparasitic angiosperms.

Oxycoryninae are clearly an ancient lineage and the presence of the taxon sister to the remaining taxa in Nicaragua may be unexpected but is not implausible. This is a relictual taxon in which numerous extinctions and range contractions would be expected simply because of their antiquity, widespread distribution at the subfamily level but highly localized distribution at the generic level, and their generalized non-specialized ancestral biology.

Figures

Fig. 14. Most parsimonious tree for Belidae obtained from analysis of the matrix in Table 1. Only unambiguous character changes are mapped on the cladogram, unique and homoplastic changes are in black and white, respectively.

Figs. 8–13. Archicorynus kuscheli. 8) Male, ventral view; 9) Ventral surface of elytra, male (PLR = pocket-like cavity); 10) Female genitalia (BC = bursa copulatrix; HLE = hook-like extensions of T VIII; HS = gonocoxites; S = spermatheca; SD = spermathecal duct; SG = spermathecal gland; S VIII = sternite VIII; T VIII = tergite VIII); 11) Aedeagus, lateral view (PN = penis; PE = pedon; TC = tectum; TG = tegmen); 12) Penis (a) and tegmen (b), separated; 13) Hindwing, male.