Helictopleurus sicardi (Paulian, 1975)

Rossini, Michele, Montreuil, Olivier, Grebennikov, Vasily & Tarasov, Sergei, 2021, Genome sequencing reveals extraordinary cephalic horns in the Madagascan dung beetle genus Helictopleurus (Coleoptera, Scarabaeinae): insight from a revision of fungicola species group, ZooKeys 1033, pp. 63-79 : 63

Helictopleurus sicardi (Paulian, 1975) Figure 4A-I

Heterosyphus sicardi Paulian, 1975: 248; Halffter and Edmonds 1982: 136; Paulian and Cambefort 1984: 50 -51; Paulian 1986: 107; Cambefort 1991: plate 4.6 (unpaginated); Paulian and Cambefort 1991: 113; Davis et al. 2002: 1224; Montreuil 2005a: 134; Wirta et al. 2008: 1080-1081 (caption and phylogenetic tree), 1087 (appendix A); Philips 2011: 27; Sole et al. 2011: 3.

Helictopleurus sicardi : Philips, 2016: 11, 13, 40-41 (synonymy Heterosyphus = Helictopleurus ).

Type material examined.

Lectotype, female (here designated): "Montagne d’Ambre. I. / Epactoides nar? / TYPE / Heterosyphus sicardi n.g. n.sp. R. Paulian det. /. Heterosyphus sicardi Paulian, 1975 des. Rossini et al. 2021 / LECTOTYPE. Helictopleurus sicardi (Paulian, 1975) Rossini et al. des. 2021" (MNHN).

Paralectoype, female: "Antsiranana / Madagascar Montagne d’Ambre Muséum Paris Coll. Sicard 1930" (MNHN).

Additional material examined.

Madagascar: " Mt. d'Ambre . -12.5281, 49.1709. 1080m. 1.i.2019. sift. MD31. V. Grebennikov, http://id.luomus.fi/NC.01" (1 male MZHF) ; same data, http://id.luomus.fi/NC.02 (1 female, MZHF; body parts disarticulated) ; same data, http://id.luomus.fi/NC.03 (1 female MZHF; body parts disarticulated, DNA material) ; same data (3 males, 7 females, MZHF); "Montagne d´Ambre. Jan 2004. Wet forest . Alt. 1300 m. fish baited trap. Iikka Hanski leg. / http://id.luomus.fi/GZ.19901. I.2004 " (1 female, MZHF) ; same data, "http://id.luomus.fi/GZ.19902. I.2004 " (1 male, MZHF) .

Diagnosis.

Within the endemic Madagascar genus Helictopleurus , H. sicardi shares a series of morphological characters with the species here assigned to the Helictopleurus fungicola group. These characters are the posterolateral margin of the pronotum extended in the propleural region with a short ridge beneath the lateral edge of the pronotum; clypeal margin of female with acute teeth at middle (three teeth as in H. fungicola and H. peyrierasi ); parameres elongated; lamella copulatrix very simple and composed by a superior and inferior leaf-like parts; and superior side of the membranous sac of the endophallus with regions covered by scale-like spines. However, H. sicardi is easily distinguished from the other members of the Helictopleurus fungicola group by the large punctation on the pronotum (very fine to absent in H. fungicola , H. peyrierasi , and H. viettei ); male with a couple of long and widely curved clypeal horns (head unarmed in the remaining species; with an acute to obtuse post-occipital tubercle in H. peyrierasi ); body completely brown (pronotum and head dark with blue to emerald green sheen, and elytra bicolored with reddish or yellow spots in the other species of the group); and elytra with rows of bright, elongated granules (granules absent in H. fungicola , H. peyrierasi , and H. viettei ).

Description of the male.

Body length and color. Body length from clypeal margin to elytral apices 7 mm, dorsal and ventral side of the body brown and bright, dorsal tegument clearly sericeous on the disc of the head, posteromedian region of pronotum and elytral interstriae; mouthparts and antennae light brown, setae light yellow to brownish.

Head. Clypeus with margin widely and evenly curved, with sides straight and parallel in proximity of the horns, genal margin curved, clypeogenal junction indicated by a short and shallow ridge, and by the base of the clypeal horns. Clypeus with two long and widely curved horns (Fig. 1D , 4A, C ), with tips rounded and slightly convergent at middle. Horns laterally flattened and basally strongly widened, bases of the horns occupy most of the lateral region of the clypeus. Clypeus smooth and shiny, clypeal disc with scattered and shallow punctures; frons with punctation coarser and denser. Frons without armature, eye opening very narrow and elongated anteroposteriorly. Antennae with eight articles; antennal club small and rounded.

Thorax. In dorsal view, pronotum narrower with respect to elytra, in lateral view slightly convex. Lateral edges rather straight and weakly divergent from posterior angles to the middle, feebly concave and sinuate from middle to anterior angles. Pronotal anterior angles narrow and obtusely acuminate. Lateral and anterior pronotal edges complete and finely margined, posterior edge with no margin. The pronotal posterior edge is extended in the propleura, beneath the lateral edge of the pronotum, with a shallow groove (Fig. 4E ). Anterosuperior region of pronotum with two parallel and high carina, anteriorly oriented and separated by a large depression.

Posteromedial pronotal region with punctation rugulose-lacunose and coarse, central and medial region without punctures, punctation more spaced in the anterior region. Several punctures associated with short and stout setae. Pronotal tegument shiny and smooth on anterior half, posterior half finely microsculptured and especially in the middle.

Propleuron weakly excavated at the bottom of the pronotal anterior angles; propleuron with two carinae, the internal carina thinner and straight, external one stronger and widely sinuate.

Episternum very narrow; mesosternal surface covered by coarse and dense punctures associated with short and stout setae, anterior region of mesosternum with a wide and smooth bead, triangularly pointed backward at middle; metasternum wide and steeply elevated with respect to the mesosternum in its superior region, surface smooth, with fine punctures on the disc and coarse punctures near the mesocoxae.

Abdomen. Elytra with eight glossy striae interrupted by a series of well-spaced and shallow punctures. Interstriae flat, with surface completely microreticulated, interstriae III-VI clearly swollen apically (carinated), interstria VIII with a longitudinal, thin ridge on basal one third (Fig. 4F ). All interstriae with one to two rows of bright granules not perfectly aligned and unevenly distributed, each granule bears a short seta bowed backward. Humeral callus well developed, elytral surface with a distinct depression nearby the callus.

Sternites ventrally visible, anterior margin with a double row of coarse and shallow punctures not perfectly aligned, three rows of punctures on the lateral most region of each sternite.

Pygidium flattened, completely margined, pygidial surface finely microreticulated and with scattered, shallow punctures.

Legs. Lateral margin of protibiae with four acute teeth distributed along the anterior half, posterior half serrated, apical and internal margin of protibia with an acute spur directed forward and slightly bent downward; ventral side of protibial with a longitudinal ridge that terminates apically with an acute tooth beneath the superior spur. Meso and metatibiae slender, enlarged apically, and respectively with two and one spiniform spurs at the apex. Profemora elongated, dorsal side smooth, ventral side with coarse and shallow punctures mostly concentrated on posterior half. Mesofemora and metafemora very slender and swollen posteriorly at middle, ventral surface with coarse and shallow punctures on posterior half, fine punctures anteriorly.

First segment of mesotarsi with four spine-like teeth in the external margin, two to three yellow setae inserted between each tooth.

Morphological variation. Minor males either with two small and straight clypeal horns that arise from the sides (Fig. 4B ) or without horns, the head is subtrapezoidal, and the anterosuperior pronotal carina are absent; the anterior half of the pronotum is feebly depressed longitudinally at middle.

Females differ from males by the clypeal margin with three teeth distinctly reflexed upward, the lateral teeth obtuse, while the central one more acuminated, posterior margin of the lateral teeth with short setae; head surface covered by coarse and shallow punctures even on the clypeus where the punctation is shallower; pronotum not depressed medially; protibia without internoapical tooth; last abdominal sternite narrower at middle.

Male genitalia. Parameres elongated, ventrally defined by two straight laminas, basoventral side of the parameres with two lateral lobes obtusely squared (BVLb, Fig. 4G, H ). Lamella copulatrix simple and consisting of a superior (SpLC) and inferior (IpLC) leaf-like part; margin of the superior part with a sharp hook (Fig. 4I ). Superior side of the membranous sac of the endophallus covered by a scale-like spines (EpS, Fig. 4I ).

Figures

Figure 1. Molecular phylogenies and morphological synapomorphies of the Helictopleurus fungicola species group A phylogenetic position of H. sicardi within Helictopleurus. Helictopleurus neoamplicollis and H. carbonarius are highlighted with colored dashed line to indicate their previous placement B COI-based phylogeny: magnification of the Helictopleurus fungicola clade and phylogenetic position of H. peyrierasi stat. rest. C synapomorphies of the Helictopleurus fungicola species group: basal pygidial ridge (BPyR); mesotarsal teeth (MsT) on the first tarsomere; parameres (P) elongated and evenly curved downward, basoventral lobes of the parameres bell shaped (BVLb); superior side of the membranous sac of the endophallus with spines (EpS); lamella copulatrix very simple (LC) D detail of the clypeal horns of the male of H. sicardi.

Figure 4. Helictopleurus sicardi A, B major (A) and minor (B) male dorsal habitus C major male lateral habitus D female dorsal habitus (lectotype) and original labels E propleural groove (PpG) F VIII interstrial ridge (IR) G, H lateral and anterior view of the aedeagus; basoventral lobes (BVLb) I endophallus: endophallic spines (EpS); superior (SpLC) and inferior (IpLC) part of the lamella copulatrix.