Aegidinus Arrow 1904

Colby, Julia, 2009, Monographic revision of the genus Aegidinus Arrow (1904) and generic phylogeny of the world Orphninae (Coleoptera: Scarabaeidae: Orphninae)., Insecta Mundi 2009 (76), pp. 1-41 : 13-14

Aegidinus Arrow 1904

Aegidinus Arrow 1904:739

Type species. Aegidinus guianensis (Westwood) , subsequent designation Paulian 1984.

Description. Scarabaeoidea , Scarabaeidae , Orphninae . Color: Reddish brown to piceous. Form: Body convex, oval, length 6.0- 12.4 mm. Sides sub-parallel, pygidium never exposed beyond apices of elytra. Head: Surface aciculate, impunctate to rugopunctate; punctures sparse to dense, small to moderate. Frons convex in males or not, never convex in females. Frontoclypeal suture variably obsolete. Eye canthus setigerous; setae moderate in length and bristle-like or long and hair-like, reddish brown to testaceous. Anterior margin of clypeus armed with median horn (majors), tubercle (minors), or unarmed in some minors and all females. Base of declivous anterior edge of clypeus with fringe of short, slender, straw colored setae. Labrum elliptical to subquadrate, exerted beyond clypeus. Lateral and anterior margins of labrum setigerous; setae moderate in length, testaceous. Each mandible with a single, external, lateral lobe. Declivous lateral edges of mandibular lobes setigerous; setae moderate to long, tawny. Pronotum: Surface aciculate, never setigerous, always micropunctate; micropunctures sparse to dense, evenly distributed over surface. Surface variably punctate; punctures sparse to dense, small to large in size, occasionally umbilicate. Lateral margin weakly serrulate, setigerous; setae moderate to long, reddish brown, inserted in troughs of serulations. Basal margin with variably complete bead, row of punctures, impressed line, or combination of previous. Females occasionally with median sulcus or depression anterior to basal margin. Disc with ovate to subtriangular fovea (major and some minor males) or depression (minor males and females) or not. In males, basolateral edge raised into carina (or not) or tumosities on each edge (major) or not (minors and females). Fovea or depression impunctate to punctate; punctures sparse to dense, small to large. Anterior margin of pronotum with median boss, tubercle, horn, or not. Scutellum: Shape subtriangular, apex rounded, typically impunctate. Elytra: Surface aciculate, micropunctate, punctures sparse to dense. Base of elytra with transverse row of U- or V-shaped, impressed lines with area anterior to line slightly raised ( Fig. 78 ). Elytra with 5 variably complete, punctate striae from impressed sutural stria to humerus, punctures variable in size and shape. Lateral margin adjacent to humerus with 1-13 setose crenulations; setae reddish brown, long ( Fig. 79 ). Legs: Each procoxa with 2 setose pits, 1 apical and 1 distal ( Fig. 80 ). Protibia with 3 lateral teeth; apical denticle ( Fig. 13 ) present in males or not (never present in females). Metatibial spinules arranged in transversely oblique rows. Venter ( Fig. 81 ): Prosternum carinate-rugose and setigerous at base and apex; setae tawny anteriorly, reddish brown elsewhere, moderate to long; smooth medially, not setigerous. Posterior prosternal process long, columnar, slender, setigerous or a short, reflexed, flattened ridge (some minor males); setae reddish brown to tawny, long. Anterior prosternal process produced into rounded knob, knob setigerous; setae reddish brown, moderate to long. Proepimeron with longitudinal carina; carina setgerous; setae tawny, moderate to long. Mesepemerion apicolaterally weakly bulbous, rugose, setigerous; setae reddish brown, moderate in length. Metasternum smooth medially. Metepimeron and sides of metasternum irregularly rugose or rugulose, setigerous; setae reddish brown, moderate to long. Metacoxae carinate rugose, setigerous; setae reddish brown, moderate in length. Abdominal sternites strongly narrowed medially, completely variolate; setigerous; setae tawny, moderate in length. Pygidium: Surface concentrically imbricate to variolate, setigerous; setae tawny, moderate in length. In lateral view, surface evenly convex.

Diagnosis. The genus Aegidinus is distinguished from the other New World and World genera by the presence of a single, external, lateral lobe on each mandible, which is unique to this genus.

Distribution. Specimens are known from Colombia, Trinidad, Venezuela, Guyana, French Guiana, Ecuador, Peru, Brazil, and Bolivia.

Composition. As circumscribed here, the genus includes 15 species, 12 of which are new.

Figures

Figures 78-81. 78) Elytra of Aegidinus sp. Arrow indicates transverse row of U- or V- shaped, impressed lines. 79) Lateral view of elytra. Arrow indicates location of margin adjacent to humerus. 80) Procoxa (dorsal surface), showing two setose pits. 81) Ventral view of A. oreibates female.

Figure 10-14. 10) Mandible of Aegidinus sp. Arrow indicates single, external, lateral lobe. Scale bar = 100 m. 11) Mandible of Aclopus sp. Scale bar = 1 mm. 12) Mandible of Aegidium sp. a) Mesal mandibular brush. b) Mandibular prostheca. Scale bar = 1 mm. 13) Galea of Paraegidium sp. Arrow indicates trapezoidal distagalea. 14) Protibia of Aegidinus sp. Arrow indicates apical denticle. Scale bar = 1 mm.