Apetasimus guttatus

Ewing, Curtis, 2006, Revision of the endemic Hawaiian sap beetle genus Apetasimus Sharp 1908 (Coleoptera: Nitidulidae), Zootaxa 1385, pp. 1-30 : 26-27

Apetasimus guttatus -group

The limited amount of material and possible extinct status for all of the species in this group make species evaluation problematic. Two of six species were described from populations collected on different islands: Apetasimus guttatus (Oahu and Hawaii) and A. atratus (Molokai, Maui, and Hawaii). Male specimens were available for the Maui and Hawaii populations of A. atratus and no obvious diagnostic characters could be quantified. Apetasimus guttatus is represented by the largest number of specimens. Three male specimens were dissected, from Waianae Mts. and Koolau Mts. on Oahu, and from Kona on Hawaii Island. Variation among the specimens was similar and greater than that among specimens of A. atratus , although not great enough to warrant splitting the three populations into separate species. Apetasimus expers (Blackburn) , proposed for a single specimen from Maui, closely resembles A. sordidus , and Sharp believed them to be synonymous pending collection of additional material; however no additional specimens have been collected.

Diagnosis

Fully winged or with wings slightly shorter than elytron and widest at apex. Mesosternum with distinct grooves accepting mesofemur. Setation of pronotum confused ( Fig. 7A ). Female pygidium wide, broadly rounded at apex. Similar in size to Orthostolus s.s. and Gonioryctus . Distinguished from Gonioryctus by setation of pronotum, which is confused in guttatus -group ( Fig. 7A ), by more transverse antennal club, with 9th segment strongly transverse, prosternal process expanded and broadly rounded apically, and apex of prosternal process weakly defexed dorsad behind coxae. Distinguished from Orthostolus s.s. by setation of pronotum ( Fig. 7A ), wider metafemora with the ventral margin strongly convex ( Figs. 7 H, 7I). Distinguished from Prosopeus by prosternal process expanded apically and weakly recurved dorsad ( Figs. 7 B, 7C). Eupetinus species are similar to guttatus -group species, and share confused pronotal setation, interstices of elytra with pale dilated and raised areas bearing tufts of setae, uneven surface of pronotum and elytra, depressed form, and small eyes with wide postgenae. The guttatus -group species are separated from Eupetinus by larger size and 3rd labial palpomere quadrate with inner margin broadly rounded ( Fig. 7 J) compared with transverse with the inner margin sinuate in Eupetinus ( Fig. 7 K). Length 4.5–6.7mm.

Figures

FIGURE 7. A. A. sordidus, pronotum (dorsal view); B. A. guttatus, prosternum (lateral view); C. A. guttatus, prosternum (ventral view); D. A. atratus, left elytron, dashed line indicates explanate margin; E. A. sordidus, left elytron, dashed line indicates explanate margin; F. A. sordidus, anal sclerite (ventral view); G. A. kauaiensis, apex of anal sclerite; H. Orthostolus nsp., metafemur (ventral view); I. A. guttatus, metafemur (ventral view); J. A. guttatus, labial palp (ventral view); K. Eupetinus impressus, labial palp (ventral view); L A. atratus, anal sclerite (ventral view).