Paraegidium Vulcano et al., 1966

Frolov, Andrey V., Akhmetova, Lilia A. & Vaz-de-Mello, Fernando Z., 2017, Revision of the South American genus Paraegidium Vulcano et al. (Coleoptera: Scarabaeidae: Orphninae), Journal of Natural History (J. Nat. Hist.) 51 (17 - 18), pp. 995-1014 : 996-998

publication ID	https://doi.org/ 10.1080/00222933.2017.1326640
publication LSID	lsid:zoobank.org:pub:BD40ACCF-3EEB-43C3-BC54-0D2BB88F679F
persistent identifier	https://treatment.plazi.org/id/03E7473F-FFDB-FFAC-FE66-FB8776E825FA
treatment provided by	Felipe
scientific name	Paraegidium Vulcano et al., 1966
status

Treatment

Type species: Paraegidium costalimai Vulcano et al., 1966 , by original designation. Paraegidium: Vulcano et al. 1966: 252 , Paulian 1984: 91, Colby 2009: 16, Frolov 2012: 783,

2013: 37, Frolov and Vaz-de-Mello 2015: 435, Rojkoff and Frolov 2017: 355.

Description

Paraegidium species are relatively small beetles (body length 5.5–9.0 mm), brown to black coloured, without pattern, and densely punctate. Mandibles subsymmetrical, without lateral processes, protruding past anterior margin of frontoclypeus in dorsal view. Frontoclypeus in males with variably shaped bilobate anterior pronotal process, which is species-specific but subject to reasonable allometric variation. Frontoclypeus of females with slightly upturned anterior margin. 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 are short, tubercle-shaped and anterior frontoclypeal process is carina-shaped. In females, pronotum is slightly depressed medially, without horns or tubercles. Scutellum narrowly rounded apically, about 1/10 length of elytra. Elytra convex, with marked humeral and apical umbones, without distinct striae or carinae, densely punctate with U-shaped punctures. Wings fully developed in all species. Metepisternon elongated, its posterior angle subtriangular and situated in distinct concavity of epipleuron. Mesocoxal cavities connected by a hole. Protibiae with 3 strong outer teeth in both sexes, without a smaller medial tooth. Procoxae without cavities. Mesotibiae without a tuft of setae ventroapically. Phallobase tube-shaped with strongly sclerotized ventral side but without differentiation of ventral and dorsal sclerites; ventroapical plate absent. Parameres with relatively simple apices, apices curved downwards and tapering, without setae or processes. Extreme apex of parameres with minute teeth laterally, visible in some species, almost indistinguishable in others. Endophallus with feebly developed 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

Paraegidium species can easily be distinguished from other members of the Aegidiini by the dense, irregular punctation and dense pubescence of the dorsal side of the body and by a bilobate or bifurcated anterior clypeal process in males. The peculiar U-shaped elytral punctures in Paraegidium are similar to those in Stenosternus costatus Karsch , the only member of the West African orphnine genus Stenosternus Karsch , although in the latter the punctures are directed cranially ( Frolov 2013; Frolov and Akhmetova 2015).

Diagnostic characters of species

Species of Paraegidium can be separated by the combination of the shape and relative length of the parameres and the shape of the anterior frontoclypeal process in males. The endophallic armature is also specific in some species although it may be not reliable in most cases. Characters of the females are not diagnostic; therefore identification of single females is not possible at this stage. It should be noted that the photos taken from the dry aedeagi do not perfectly represent the shape and specifically the relative position of the phallobase and parameres. When the aedeagus dries out, the parameres bend downwards to various degree depending on the sclerotization of the base of the parameres and content of the phallobase (whether it has the endophallus). The shape of the aedeagi is more consistent in glycerol.

Species composition and distribution

The genus Paraegidium was previously known from the Atlantic Forest and southern Amazon regions. Judging from the material available to us, the genus range covers most of the central part of South America from Guiana Shield in the north to the Peruvian Yungas in the west and to extreme southeastern Brazil. The majority of the localities lie within the Brazilian Plateau.

Key to Paraegidium species (males)

1. Parameres longer: ratio phallobase length/paramere length 2.2–1.9 ( Figures 1 View Figure 1 (c), 2(f), 3(f), 4(e)). Lobes of anterior frontoclypeal process angulate, rounded or truncated but not bimodal or bifurcated ( Figures 1 View Figure 1 (a), 2(a, d, e), 3(a, c, d), 4(a, d)........ 2

– Parameres shorter: ratio phallobase length/paramere length 2.5–2.7 ( Figures 5 View Figure 5 (f), 6 (d)). Lobes of anterior frontoclypeal process bimodal or bifurcated ( Figures 5 View Figure 5 (a, c, d), 6(a–c)) (may appear truncated in larger males depending on angle of view, Figure 5 View Figure 5 (a)). .............................................................................................................................................................. 5

2. Parameres longer: ratio phallobase length/paramere length 1.9 ( Figure 1 View Figure 1 (c)). Lobes of anterior frontoclypeal process truncated ( Figure 1 View Figure 1 (a))....... P. monneorum sp. nov.

– Parameres shorter: ratio phallobase length/paramere length 2.1–2.2 ( Figures 2 View Figure 2 (f), 3 (f), 4(e)). Lobes of anterior frontoclypeal process rounded or angulate ( Figures 2 View Figure 2 (a), 3 (a), 4(a))..................................................................................................................................................... 3

3. Base of parameres wider in lateral view ( Figure 2 View Figure 2 (f)). Apices of parameres wider in dorsal view ( Figure 2 View Figure 2 (g))................................................................................. P. barretoi sp. nov.

– Base of parameres narrower in lateral view ( Figures 3 View Figure 3 (f), 4(e)). Apices of parameres narrower in dorsal view ( Figures 3 View Figure 3 (g), 4(f))............................................................................... 4

4. Lobes of anterior frontoclypeal process angulate ( Figure 3 View Figure 3 (a, c, d)). Group of spinules in endophallus larger and elongated ( Figure 3 View Figure 3 (h))......................................... P. costalimai

– Lobes of anterior frontoclypeal process rounded ( Figure 4 View Figure 4 (a, d)). Group of spinules in endophallus smaller ( Figure 4 View Figure 4 (g))............................................................. P. pokornyi sp. nov.

5. Parameres longer: ratio phallobase length/paramere length 2.5 ( Figure 5 View Figure 5 (f)). Apices of parameres more or less acute in lateral view. Lobes of anterior frontoclypeal process bimodal (sinuate apically, Figure 5 View Figure 5 (a, c, d))......................... P. howdeni sp. nov.

– Parameres shorter: ratio phallobase length/paramere length 2.7 ( Figure 6 View Figure 6 (d)). Apices of parameres rounded in lateral view. Lobes of anterior frontoclypeal process bifurcated ( Figure 6 View Figure 6 (a–c))............................................................................... P. oliveirai sp. nov.