Onthophagus (Palaeonthophagus) roessneri Ziani 2016, new species
Creators: name: Ziani, Stefano
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Onthophagus
Onthophagus roessneri

description: Onthophagus (Palaeonthophagus) roessneri, new species   
Fig. 1–5  
 Type Locality. IRAN, Fars prov.: pass between Komehr and Ardakan, 2700/ 2800 m, 30°23’14”N; 51°58’35”E.   
 Type Series. Holotype ♂: IRAN, Fars prov.: pass between Komehr and Ardakan, 2700/ 2800 m, 30°23’14”N; 51°58’35”E, 24/ 25.iv.2014, W. Heinz leg. Allotype: IRAN, Isfahan, 10 km SW Quamsar, Kamoo, 2650 m, 33°39’37”N; 51°16’04”E, 12.v.2012, D. Frenzel leg.   
 Type Depositories. Holotype at NMEG, allotype at DFCS.   
 Type Labelling. Holotype bears three labels, as follows. 1 st, white, printed in black “IR (Fars): Pass 27/ 2800 m / zw.Komehr u. Ardakan / Heinz leg. 24/25.IV.2014”; 2 nd, yellow, printed in black “collection / NATURKUNDE- / MUSEUM ERFURT”; 3 rd, red, printed in black “ Holotype / Onthophagus (Palaeonthophagus) / roessneri mihi / S. Ziani, 2015”.   
 Etymology. The new species is dedicated to Eckehard Rössner, specialist in Scarabaeoidea, who first recognized that the two specimens of the type series could belong to an undescribed species.   
 Description. Holotype. (Fig. 1). Male, length 6.1 mm, width 3.3 mm. Pronotum slightly shorter than elytra (length ratio = 0.83).   
Black, upper side relatively shiny, but with a distinct isodiametric microreticulation; pubescence yellow to dark yellow or grey; antennal scape, pedicel and funicle dark yellow, antennal club dark grey.  
Head short, clearly wider than long (width/length ratio = 1.70). Clypeus round on either side of median emargination, anterior angles broadly round, sides evenly arcuate with no sinuations, genae distinctly protruding from eyes. Clypeofrontal carina moderately elevate, bent posteriorly, edges in contact with clypeogenal sutures; occipital carina clearly wider at base than clypeofrontal carina, almost reaching lateral margins of head, sinuate at sides and slightly in middle. Clypeal surface with rather coarse, subconfluent, setigerous punctures; frontal surface doubly punctate, with large setigerous punctures widely spaced, more so anteriorly, separated from one to two times their diameters posteriorly; setae grey, long, thin, erect, only slightly thicker basally, gradually thinner apically.  
Pronotum (Fig. 2) convex, declivous anteriorly, with anteromedian prominence and a weak but distinct anterolateral tubercle on either side; prominence slightly more projecting forward than anterolateral tubercles, more than twice wider than long. Anterior angles distinctly produced, sides sinuate behind them. Dorsal surface setigerously punctate, punctures simple or slightly umbilicate, broad, shiny, deep, well-defined, separated by 1–3 diameters on disc, more widely spaced basally; bristles dark yellow, moderately long.  
Elytral striae shiny, weakly impressed, with punctures barely crenating interstrial sides. Interstriae flat, irregularly granulate, posterior margin of each granule with a small, setigerous puncture; setae dark yellow, thin, erect.  
Pygidium with widely spaced setigerous punctures; setae dark yellow, long, thin.  
Protibial spur slightly angularly bent inward and downward; inner angle of protibial apex with a small denticle curved downward.  
Genital armature (Fig. 4–5). Parameres short, sinuate along sides, subrectangular apically, with a slight but distinctly produced latero-proximal denticle; lamella copulatrix reniform, right lobe in ventral vision thin, slightly produced outward apically.  
 Allotype (Fig. 3). Length 6.5 mm, width 3.7 mm. As usual in the species of the semicornis group, the secondary sexual dimorphism is apparent only in shape and size of the pygidium and the sixth abdominal sternite, and in the lack, in females, of the small denticle in the inner angle of the protibial apex. The allotype thus resembles the holotype, particularly in the external structures of the pronotum and head.   
 Distribution and Ecology. The new species is known from two high mountain localities of southcentral Iran (Fars and Isfahan provinces). Unfortunately, no information is available on how specimens have been collected. I hypothesize the new species to be a true nidicolous beetle, i.e. a pholebiont or a pholephile more or less strictly associated with the nests or burrows of rodents. The protibial spur, stout and bent inward and downward as in all pholeophilous Onthophagus species, gives credit to this assumption.   
 Discussion. The diagnosis of the semicornis species group, as given by Ziani and Gudenzi (2007), follows: “The species of Onthophagus (Palaeonthophagus) semicornis species-group are of medium size (length 4.8-7.5 mm), pronotum 0.75 to 0.96 times shorter than elytra, black, upper side with distinct isodiametric microreticulation, dorsal pubescence yellowish white to reddish yellow. Head short, clearly wider than long, clypeus more or less emarginate at middle, in one species arcuately excised, sides indistinctly or not at all sinuate in front of genae which are protruding; clypeo-frontal carina distinct in both sexes, occipital carina with a more or less elevate, sometimes apically bifurcate lamina. Pronotum convex, strongly declivous towards anterior edge, with a distinct anterolateral tubercle on either side and with an anteromedian gibbosity, sometimes divided in two small tubercles; anterior angles more or less obtusely produced, sides sinuate behind them; pronotal surface punctuate, each puncture usually with a small granule at the anterior margin; bristles of pronotal surface progressively widened from base to top. Elytral surface with setae only slightly or not at all thicker basally than distally. Fore, middle and hind femora ventrally with small, rather sparse setigerous punctures.   
Aedeagus slender, apex of parameres curved ventrally, divergent and always more or less hooked, the outer margin of parameres bearing a proximal denticle. Copulatory lamina overall shape oval or quadrangular, excluding the basal emargination.  
Epipharynx nearly oval, round at sides, anterior margin barely or not at all emarginate at middle; tylus, in ventral view, with very close strong setae, acropariae consisting of long setae of different thickness; outline of gymnopariae scarcely sclerotized.  
Secondary sexual characters almost entirely restricted to the difference in shape and size of pygidium and sixth abdominal sternite.”  
 Onthophagus (Palaeonthophagus) roessneri n. sp. can be included in this group, and particularly in the lineage of O. semicornis, with Onthophagus eulaminicornis Pittino, 2006, Onthophagus sacharovskii Olsoufieff, 1918, Onthophagus samai Ziani, 2011 and Onthophagus semicornis (Panzer, 1798). With these species, distributed in west-central Palaearctic, O. roessneri shares the shape of the lamella copulatrix, overall oval, excluding the basal emargination, and its anterior angles distinctly round. The new species is most similar to O. sacharovskii (Fig. 6), from which can be distinguished by its shining dorsal surface (O. sacharovskii is duller), the simple, fine and more widely spaced frontal punctures, simple and spaced (granulate, coarse, sometime subconfluent in O. sacharovskii), the simple, slightly umbilicate and more widely spaced pronotal punctures (granulate and more closely spaced in O. sacharovskii, as in Fig. 7), and the anteromedian pronotal prominence transverse, more than twice wider than long (about twice wider than long in O. sacharovskii). Furthermore, the parameres are subrectangular apically (subquadrangular in O. sacharovskii, as in Fig. 8), and the right branch of the lamella copulatrix is in ventral view slightly produced outward apically (distinctly produced outward, almost hook shaped, in O. sacharovskii, as in Fig. 9).
description: Published as part of Ziani, Stefano, 2016, Studies on Palaearctic Onthophagus associated with burrows of small mammals. V. A new species of the semicornis group from south-central Iran (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini), pp. 1-6 in Insecta Mundi 2016 (470) on pages 1-3, DOI: 10.5281/zenodo.5170491