Aegidiellus Paulian, 1984

Frolov, Andrey V., Akhmetova, Lilia A. & Vaz-de-Mello, Fernando Z., 2017, Revision of the Neotropical scarab beetle genus Aegidiellus Paulian (Coleoptera: Scarabaeidae: Orphninae) with description of two new species, Journal of Natural History (J. Nat. Hist.) 51 (29 - 30), pp. 1767-1779 : 1768-1770

Aegidiellus Paulian, 1984

Type species: Phileurus alatus Castelnau, 1840 , by original designation.

Aegidiellus: Paulian 1984: 86 ; Colby 2009: 5; Frolov 2012: 796; Frolov and Vaz-de-Mello 2015: 136; Frolov 2013: 42; Rojkoff and Frolov 2017: 355.

Description

Aegidiellus comprises small to medium-sized beetles (body length 7–11 mm), brown to black coloured, without pattern. Mandibles subsymmetrical, small, without lateral processes, protruding past anterior margin of frontoclypeus in dorsal view. Frontoclypeus without tubercles, horns or ridges. Propleurae with carinae separating anterolateral areas from basal area. Pronotum of ‘major’ males with deep excavation in the middle and two horn-shaped, lateral pronotal processes directed somewhat anteriorly. In ‘minor’ males, pronotal and head armature less developed: lateral pronotal processes short, tubercle-shaped and anterior frontoclypeal process carina-shaped. In females, pronotum impressed anteriorly on disc and with a tubercle medially on anterior margin. Scutellum narrowly rounded apically, about 1/ 10 length of elytra. Elytra convex, with marked humeral and apical umbones. Elytral striae as longitudinal rows of punctures; sutural stria normally distinct as a depressed furrow in apical half of elytron; elytra without elevated, longitudinal keels or smooth stripes on disc. Wings fully developed in all species. Metepisternon elongated, its posterior angle slightly triangular and situated in distinct concavity of epipleuron. Mesocoxal cavities connected by a hole. Protibiae with three strong outer teeth in both sexes, with a smaller, medial tooth in majority of males. Mesotibiae without tuft of setae ventroapically. Plectrum widely triangular, rounded apically, with a few sensory setae. Stridulatory file with 100–110 fine, slightly curved carinae (carinae counted according to Frolov and Akhmetova (2016)). Phallobase tubeshaped with strongly sclerotized ventral side but without differentiation of ventral and dorsal sclerites; ventroapical plate absent. Parameres symmetrical, apices with short, dense setae. Spiculum gastrale wide, triangular. Endophallus without armature. Subcoxites with sparse, long setae medioapically. Coxites triangular, with row of short spinules mediobasally and long, sparse setae apically. Stili not separated from coxites.

Diagnosis

Aegidiellus is a member of the putative Aegidiini clade, which also includes Aegidium , Paraegidium and Onorius . These genera share the following characters: mandibles without lateral processes, mesocoxal cavities connected by a hole; and metatibiae without transverse carina ( Paulian 1984; Frolov 2012). Aegidiellus can be separated from Paraegidium by the sculpture of the dorsum of the body, which is almost glabrous and sparsely punctate as opposed to being densely, irregularly punctate and densely pubescent in the latter; from Onorius it can be separated by the prominent mandibles (well visible in dorsal view), and relatively slender tarsomeres. Aegidiellus is externally most similar to Aegidium but can be separated from it by the elytral striae as longitudinal rows of punctures, sutural stria normally distinct as a depressed line on apical half of elytron, and elytra without elevated longitudinal keels or smooth stripes on disc. From all Aegidiini , Aegidiellus differs in having setose apices of parameres and female with a tubercle on the anterior margin of the pronotum.

Diagnostic characters of species

Aegidiellus species are similar externally and the only character that reliably diagnoses the species is the shape of the aedeagus and especially the parameres. Females of Aegidiellus cannot be separated at present.

Species composition and distribution

Aegidiellus includes three species distributed in the low coastal parts of the Atlantic forest ecoregion.

Key to Aegidiellus species (males)

1. Phallobase wider, its anterodorsal margin not protruding ( Figure 1 (d)). Parameres wider, their lateral margin with deep sinuation forming a tooth basally ( Figure 1 (e,f)) .............................................................................................................................. A. dentipenis sp. nov.

– Phallobase narrower, its anterodorsal margin membranous, protruding ( Figures 2 (d) and 4(c)). Parameres narrower, their lateral margin without sinuation and tooth ( Figures 2 (e) and 4(d)) ...................................................................................................................... 2

2. Parameres with apices wider ( Figures 2 (e) and 3(d)). Dorsal side of parameres straight to slightly sinuate in lateral view ( Figures 2 (d) and 3(c)) .................. A. alatus

– Parameres with apices narrower ( Figure 4 (d)). Dorsal side of parameres convex in lateral view (Figure (4c)) ................................ ................................ Aegidiellus zezaoi sp. nov.

Figures

Figure 1. Aegidiellus dentipenis¸ holotype male (a, c–f). Habitus in dorsal view (a), locality map (b; triangle – A. dentipenis; circle – Aegidiellus zezaoi), spiculum gastrale (c); aedeagus in lateral view (d), parameres in dorsal (e) and apical (f) view.

Figure 2. Aegidiellus alatus¸ neotype, male. Habitus in dorsal (a) and lateral (b) view, labels (c), aedeagus in lateral view (d), parameres in dorsal view (e), locality map of A. alatus (f).

Figure 4. Aegidiellus zezaoi. Holotype, male (a, c–e), paratype, female (b). Habitus (a, b), aedeagus in lateral view (c), parameres in dorsal view (d), spiculum gastrale (e).