Gordonius, Skelley & Dellacasa & Dellacasa, 2009

Skelley, Paul E., Dellacasa, Marco & Dellacasa, Giovanni, 2009, Gordonius rhinocerillus, a new genus and species of Colombian Aphodiini (Coleoptera: Scarabaeidae: Aphodiinae), Insecta Mundi 2009 (67), pp. 1-4 : 1-2

Genus GORDONIUS , new genus

Type species. Gordonius rhinocerillus sp. nov., here designated (gender masculine).

Diagnosis. Frontal suture not tuberculate; pronotum with marginal line at base, hind angles not truncate; scutellum small, triangular; elytra glabrous; protibia finely punctate dorsally, ventral inner margin of protibia with 3 widely spaced tubercles; metatibiae apically fimbriate with equal, very short spinules; male with prominent clypeal horn. Gordonius is the only New World aphodiine with a horn.

Description. Body oblong, strongly convex, moderately shining, glabrous ( Fig. 4-9 ); pale brown. Head with clypeus anteriorly truncate, rounded at sides; genae weakly protruding past eyes; frontal suture not tuberculate. Pronotum transverse; strongly convex; with irregularly spaced, coarse and fine punctures; with marginal line at base. Scutellum small, triangular. Elytra strongly convex, deeply striate; intervals moderately convex. Protibiae distally tridentate, proximally weakly serrulate along outer margin, upper face sparsely punctured, inner ventral margin with 3 widely spaced strong tubercles. Mesotibia similar to metatibia in shape, abruptly dilated at apex. Metatibiae with strong transverse carinae on outer surface ( Fig. 6, 9 ); apically fimbriate with very short, equal spinules, row of setae along inner margin only (lacking medial-ventral longitudinal row of setae). Pygidium alutaceous, glabrous, sporatically punctured; weakly shining in basal half, subrugosely punctured on distal half with sparse, very elongate setae toward apex; apical margin glabrous. Sexual dimorphism in male clypeus with strong anteromedial horn (male Fig. 4-5 , female Fig. 7-8 ). Aedeagus with parameres in lateral view obtusely rounded apically, in dorsal view moderately widened toward apex (Fig.

2-3). Epipharynx feebly, inwardly sinuate at ante-

rior margin; widely rounded at sides. Epitorma

crown-shaped. Corypha not protruding beyond the

fore margin; with 4 strong, rather elongate apical

spinules. Pedia pubescent with rather elongate

chaetae densely, irregularly arranged throughout.

Chaetopariae dense, moderately elongate (Fig. 1).

Distribution. Colombia.

Etymology. This genus is named in honour of

our friend Robert D. Gordon, eminent specialist of Figure 1-3. Gordonius rhinocerillus sp. nov. (Cauca, 6000’, 20 km W Silvia, Colombia. 1) Epipharynx. 2-3) Aedeagus,

American Coccinellidae and Aphodiinae. dorsal and lateral view.

Remarks. Gordonius appears most similar to

Trichaphodiellus brasiliensis (Laporte) . Trichaphodiellus lacks the basal pronotal marginal line, has crenate inner ventral margin of the protibia, has the dorsal protibial surface densely punctate, has the mesotibia more triangular and gradually widened to apex (distinctly different from metatibia), and metatibia with complete medial-ventral longitudinal row of stout setae in addition to the fine row of setae along the inner margin.

Gordonius keys to couplet 163 in the key of Aphodiini by Dellacasa et al. (2001), but is immediately distinguished from other genus-group taxa by the punctate anterior surface of the protibia, distribution, and sexually dimorphic clypeus with a horn in males.

Figures

Figure 4-9. Gordonius rhinocerillus sp. nov. 4-6) Male habitus; dorsal, lateral and ventral. 7-9) Female habitus; dorsal, lateral and ventral.