Dichotomius (Selenocopris) femoratus Howden and Young 1981
Creators: name: Valois, Marcely C.
name: Silva, Fernando A. B.
name: Vaz-de-Mello, Fernando Z.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Dichotomius
Dichotomius femoratus

description: Dichotomius (Selenocopris) femoratus Howden and Young, 1981
(Figures 1 (c), 3(a,e,h,k,l), 4(e,f), 5(d,e,j), and 6)
Dichotomius femoratus Howden and Young 1981: 128; Krajcik 2006: 53; 2012: 91; Solis and Kohlmann 2012: 6; Vaz-de-Mello and Nunes 2016: 299.
Diagnosis
Among the species in the globulus group, D. femoratus is a central American species with records in Costa Rica (Solis and Kohlmann 2012) and Panama, in this latter country being found in sympatry with D. gamboaensis (Figure 6). However, D. femoratus is the only known species of the globulus group of which both males and females have elytral interstriae distinctly convex, smooth medially with shagreened microsculpture along the lateral edges near striae (Figure 3 (h), ShMicro). Other species of the globulus group have almost the entire surface of elytral interstriae covered with shagreened microsculpture, except by small, smooth dots usually concentrated along the medial portion of the interstrial surface. Additional charaters useful to distinguish D. femoratus from others in the group are: body elongate (Figure 1 (c)); male clypeal teeth triangular and upturned, separated by deep V-shaped emargination; frons and gena covered with sparse ocellate punctures, spaced by their diameter; clypeofrontal region transversally elevated, bearing a central knob truncated at the apex; pronotal disc sparsely punctate, punctures irregularly spaced (Figure 3 (e)); anterior declivity of pronotum as long as one-third the pronotal length (Figure 1 (c)); pygidium slightly angulate at the apex.
Redescription (male)
Body length: 13–14 mm. Dorsum black, shiny on head, pronotum and medial region of interstriae (Figure 1 (c)). Head: clypeal edge bidentate, teeth acute, separated by a deep V-shaped emargination. Clypeogenal junction notched. Clypeal surface almost smooth, with scattered ocellate punctures posteriorly and slightly transverse ridges near anterior edge. Cephalic process forming a low transverse carina with a small central tubercle, emarginate at the apex. Antennal club with light brown tumescence. Thorax: pronotum approximately twice wider than long. Pronotal disc convex, anteromedian region with a shallow central excavation; surface with sparse ocellate punctures spaced by their diameter or more. Mid-longitudinal sulcus well impressed, filled with ocellate punctures. Whole surface of hypomera covered with ocellate punctures, anterior and lateral regions with punctures bearing short orange setae. Prosternum filled with ocellate punctures. Mesoventrite filled with ocellate punctures usually bearing short orange setae. Metaventrite surface with ocellate punctures, except on disc; punctures on anterior region usually bearing short orange setae. Meso-metaventral suture distinct. Anterior lobe of metaventrite half the length of metafemora. Metaventrite with mid-longitudinal sulcus indistinct. Lateral lobes of metaventrite with ocellate punctures larger than those on anterior region. Elytra: slightly convex in lateral view. Humeral callus distinct. Striae thin and with ill-defined punctures, spaced by twice their diameter. Legs: protibial spur curved at apical fifth. Metatibial spur deeply emarginate apically. Ventral surface of the profemora covered with coarse setiferous punctures concentrated on apical half. Ventral surface of the meso and metafemora almost smooth, apex with indistinct ocellate punctures. Meso and metafemora bearing a thin longitudinal groove along apical half, usually present along the basal half, but feebly marked. Abdomen: ventrites covered with ocellate punctures at lateral regions, medial region in a single row along anterior edge. Sixth abdominal ventrite as long as fifth, flat, lacking tubercle medially. Pygidium slightly wider than long, triangular. Surface of the pygidial disc with ocellate punctures concentrated along anterior half, and spaced by half their diameter. Apex of the pygidium margined. Tegmen: in dorsal view, paramera rectangular, one-third longer than its width medially, apex rounded; inner edge curved outward along its entire length (Figure 4 (e)). Apical half significantly narrower than base in lateral view. Dorsal surface of paramera smooth (Figure 4 (e)). Ventral sclerotised membrane between paramera thinner at basal fourth; slightly angulate at lateral portions (Figure 4 (f)). Endophallus: ME inferior projections separated by a broad V-shaped emargination (Figure 5 (d)). ME with a feeble longitudinal fold in the median inferior region (Figure 5 (e)). A and SA endophallites thin, C-shaped in lateral view; SA endophallite with reticulate texture inferiorly (Figure 5 (j)). FLP endophallite C-shaped in lateral right view, inferior region shorter than superior one; surface of the C-shaped region with irregular projections (Figure 5 (j)). SRP endophallite approximately C-shaped (Figure 5 (j)). Female: differs from male by clypeal teeth larger and acute, separated by a deep V-shaped emargination. Clypeal surface with well-defined transverse wrinkles. Pronotum lacking distinct anterior declivity; mid-longitudinal sulcus distinct. Sixth abdominal ventrite as long as fifth, bearing a knob medially Figure 3 (l). Pygidial disc distinctly convex and angulate at the apex, sparsely punctate, punctures concentrated near anterior edge. Apical margination of the pygidium absent.
Type material examined
Holotype of Dichotomius femoratus ♂ [MCZ]: ‘ PANAMÁ: CANAL ZONE;/ Barro colourado Isl./ 8.vi.1978 ’ // ‘ N.E Woodley,/Collector/trap baited/with Lep. Frass’ // ‘ HOLOTYPE / DICHOTOMIUS /FEMORATUS / H. Howden and/O. Young’ // ‘M.C.Z./ Holotype /32,558’ // ‘SEM’. Examined via photographs.
Additional material examined
PANAMA: Prov. Cerro Azul: 850 m. 17 July 1998. M. Hardy (1♂ 2♀♀, CEMT); El Valle. [– 80,12,141; 8,611,646]. 20–22 June 2013. V. Benes (2♀♀, CEMT).
Taxonomic remarks
Dichotomius femoratus was formerly identified by its distinctive pattern of microsculpture on the elytral interstriae, which appears to be shagreened near striae and smooth medially. However, the examination of the type material of D. globulus has revealed that some specimens have a very similar pattern of elytral microsculpture to that of D. femoratus. The type material of D. globulus is composed of one male (lectotype) and four females (paralectotypes). All females have the surface of the elytral interstriae shining at centre and shagreened along the lateral portions near striae, whereas the male has almost the entire surface of interstriae shagreened, with at most scattered smooth dots on the medial portion. To distinguish females of D. femoratus from those of D. globulus, the following characters can be used: body elongate (globose in D. globulus) surface of frons and genae with scattered ocellate punctures (Figure 3 (d)) (densely distributed in D. globulus), and pronotal punctures irregularly spaced (umbilicate in D. globulus).
description: Published as part of Valois, Marcely C., Silva, Fernando A. B. & Vaz-de-Mello, Fernando Z., 2022, A taxonomic revision of the globulus species group of Dichotomius Hope, 1838 (Coleoptera: Scarabaeidae: Scarabaeinae), pp. 119-147 in Journal of Natural History 56 (1 - 4) on pages 133-135, DOI: 10.1080/00222933.2022.2046887, http://zenodo.org/record/6530252