Sclerodermus chicomendesi Azevedo & Colombo, 2022

Azevedo, Celso O. & Colombo, Wesley D., 2022, Synopsis of the Neotropical Sclerodermus Latreille (Hymenoptera, Bethylidae) with description of a new species attacking human beings, Zootaxa 5124 (5), pp. 501-519 : 509-513

Sclerodermus chicomendesi Azevedo & Colombo , sp. nov.

Figs 1H , 3–4

Differential Diagnosis. This species is similar to S. spilonotum in having the head elongate with outcurved sides, and the metapectal-propodeal disc slightly constricted anteriorly. However, this species has the mandibles with three apical teeth and the clypeus with median lobe trapezoidal, whereas S. spilonotum has the mandibles with two apical teeth and the clypeus with the median lobe short and with its apical margin subangulate. Besides the characters highlighted in the key, the pattern of colour is significantly different, this species has the head and mesosoma varying from light castaneous to castaneous, with the metasoma contrastingly darker, whereas S. spilonotum is mostly dark castaneous.

Description, female. Measurements. Body 2.32 mm long. Head 0.34 mm long and 0.32 mm wide. Frons 0.17 mm wide. Eye 0.11 mm long. Wings 0.08 mm. Colour. Head castaneous, mesosoma light castaneous to castaneous, metasoma dark castaneous, clypeus castaneous, antenna and palpi light castaneous, mandible castaneous with dark apex, legs light castaneous to castaneous. Wings hyaline.

Head. Mandible progressively narrowing apicad, with three sharpened apical teeth in oblique series. Median clypeal lobe short and trapezoidal, median area elevated and carinate, carina straight in profile, anterior margin upcurved medially. Malar space broad, without sulcus. Pedicel longer than flagellomeres I–II together. Flagellomeres I–X wider than long. Antennal pubescence appressed, very short and dense, velvet-like, with some suberect or erect setae outstanding progressively shorter distad. Ocelli absent. Frons very weakly coriaceous, punctures very sparse and inconspicuous. LH 1.1 WH, WF 0.55 WH, WF 1.61 HE. Vertex slightly outcurved. Sides of head slightly outcurved, head wider posteriorly eye. VOL 2.29 HE.

Mesosoma. Dorsal pronotal area subquadrate in dorsal view, slightly longer than wide, with anterior humeral angle rounded. Mesoscutellum equilaterally triangled. Metapectal-propodeal disc as long as wide, without metapostnotal median and posterior carinae, surface of disc progressively depressing posterad. Propodeal declivity subvertical, ecarinate. Mesopleuron without pits and foveae. Tegula very small as scale. Micropterous, wing slightly longer than tegula, veins absent. Profemur 2.1 as long as wide. Mesotibia spinose.

Metasoma. Stout, longer than head and mesosoma together, 0.57 as long as body, apical margin of sternites IV–VI bi-emarginated, surface of last sterna somewhat flat.

Description, male. Measurements. Body 1.85 mm long. Head 0.26 mm long and 0.22 mm wide. Frons 0.13 mm wide. Eye 0.11 mm long. Forewing 1.46 mm long. Hind wing 1.23 mm long. Colour. Head, clypeus, antenna, mandible, mesosoma, metasoma, coxae, trochanters, pro- and mesofemora dark castaneous, metafemur, tibiae and tarsi castaneous, palpi light castaneous; forewing subhyaline, veins transparent, progressively lighter posterad.

Head. Mandible evenly wide along its length, with three apical teeth, two lower sharpened, upper one rounded. Clypeus with short trapezoidal median lobe, apical margin almost straight, median carina complete, but weak, straight in lateral profile, lateral lobe defined, short. Antenna, pedicel much longer than wide, flagellomere I about as long as wide, remaining flagellomeres distincly longer than wide, flagellomeral pubescence suberect, setae slighlty longer than half flagellomeral diameter. Distance between toruli about 0.5 their own diameters. Eye with few setae. Frons weakly coriaceous, with very few indistinguisable punctures, with weak and short anterior median line. LH 1.18 WH, WF 0.6 WH, WF 1.18 HE. OOL 1.19 WOT; ocellar triangle distant from vertex crest 0.33 DAO, its frontal angle slightly acute. Vertex weakly outcurved, corners broadly rounded, temple almost parallel in frontal view. VOL 1.08 HE. Malar space evident, about one third of mandibular basal width, malar line sulcate and complete, giving rise closed to dorsal mandibular condyle. Occipital carina weak posteriorly and laterally, absent ventrally. Hypostoma evenly curved. Medioccipito-genal carina complete.

Mesosoma. Pronotal dorsal area ecarinate, bell-shaped with anterior margin evenly outcurved, surface evenly depressed forward, pronotal flange short and subvertical, almost indistinguisable from pronotal dorsal area. Notaulus very ill-defined, weak and inconspicuous, almost indistinguisable. Parapsidal signum very ill-defined, weak and inconspicuous, almost indistinguisable, present only on posterior half of anteromesoscutum. Mesoscutummesoscutellar sulcus well-defined and deep, anterior margin straight and posterior margin evenly incurved, so that sulcus widens laterally, but not forming lateral pits. Metapectal-propodeal disc weakly coriaceous almost polished, 1.11 as wide as long, side parallel, metapostnotal median, metapostnotal lateral and posterior transverse carinae absent, posterior area smoothly depressed postarad. Propodeal declivity ecarinate, very weakly coriaceous laterally and progressively polished mesad. Propodeal spiracle round placed fully at lateral surface of metapectal-propodeal complex. Mesopleuron with subalar impression narrow as sulcus, mesepimeral sulcus inconspicuous, mesopleural pit very shallow and very small, posterior obliquus sulcus, anterior and upper mesopleural pit absent, transepisternal line inconspicuous. Prepectus concave and coriaceous. Forewing with costal cell opened by absence of costal vein; radial cell fully closed; Rs&M vein wider than other; M+Cu, cu-a and 2r-rs&Rs veins absent, fringes of anterior and apical margins distinctly longer. Hind wing with three distal hamuli, median hamulus slightly closer to apical one, without any proximal hamuli, fringes of apical and posterior margins distinctly longer. Legs not spinose. Profemur 3.4 as long as wide.

Metasoma.Weakly coriaceous, segments II–III about 0.5 metasomal length.Hypopygium somewhat sublogenzeshaped, spiculum conical, not stalk-shaped at all, posterior margin outcurved. Genitalia: harpe divided in two arms, ventral arm longer and much wider than dorsal arm, about evenly wide, apical margin broadly slighlty outcurved with ventral corner rounded and dorsal corner angulate, ventral margin slightly outcurved, dorsal somewhat straight, dorsal arm somewhat logenze-shaped when seen in its in full lateral view, apical margin narrowly rounded, ventral margin outcurved, dorsal margin straight; cuspis rectangular when seen in its full lateral view, wide, apical margin somewhat straight, with small emargination close to ventral corner; aedeagus with of pair of rounded apical lobes.

Material examined. Holotype, ♀, BRAZIL, Rio Grande do Sul, Porto Alegre , 5.ix.2016, manually collected in a home office in the urban area ( MNRJ) . Allotype ♂, paratypes 1♂ and 7♀, same data as holotype ( MNRJ) .

Remarks. This new species is similar to S. spilonotum as aforementioned in the Differential Diagnosis section. The main differences are related to the coloration, number of mandibular teeth and shape of the median clypeal lobe. This can seem limited like morphological information to distinguish any putative new species of Sclerodermus . However, several of the sclerodermine genera and species have reduction of structures and extreme polymorphism ( Vargas et al. 2020), which results in additional difficulties in delimiting genera and species, mostly because of the aptery. Such is the scenario for Sclerodermus , where there are few characters to provide confident taxonomic delimitation of species. For instance, the key to the females of the Nearctic species of Sclerodermus by Evans (1978) is based on coloration and shape of median clypeal lobe; and the key for the females of the French species by Berland (1928) is based only on coloration. Bernard & Jacquemin (1948) delimited the Northern African species of Sclerodermus based on mandibular teeth and shape of the median clypeal lobe. In summary, the reduction of structures in apterous forms constrains the delimitation of Sclerodermus species to just a few morphological characters.

Host. This new species was found attacking a woman in her office in the municipality of Porto Alegre, South Brazil. Her office has wood furniture, which was observed to have many holes bored by Tricorynus Waterhouse, 1849 , Ptinidae , Mesocoelopodinae ( Fig. 6 ), from where both Sclerodermus chicomendesi n. sp. and its host Tricorynus beetles were observed leaving the furniture several times. This species of Sclerodermus frequently attacked the woman causing Erythematous papular injury in her skin ( Fig. 7 ).

Etymology. This species is named after Chico Mendes, who was one of the greatest Brazilian environmentalists, fighting for the rubber tappers against illegal farmers and land invaders mainly in the Amazonian Rain Forest in Acre, Brazil.

Figures

FIGURE 1. Neotropical Sclerodermus, holotype females, habitus in dorsal view. A. S. domesticus; B. S. galapagensis; C. S. iridomyrmicicola; D. S. macrogaster; E. S. spilonotum; F. S. soror; G. S. wilsoni.; H. S. chicomendesi sp. nov. Scale-bars: 100µm.

FIGURE 3. Sclerodermus chicomendesi sp. nov., female. A. Habitus, lateral view; B. Habitus, dorsal view; C–D. Head (C frontal view, D lateral view); E. Mesosoma, lateral view). Scale-bars: 100µm, except 200µm for A–B.

FIGURE 4. Sclerodermus chicomendesi sp. nov., male. A. Habitus, lateral view; B–C. Head (B dorsal view, C frontal view); D. Mesosoma, lateral view; E. Forewing, dorsal view; F. Hypopygium, ventral view; G–I. Genitalia (G dorsal view, H ventral view, I lateral view). Scale-bars: 100µm.

FIGURE 6. Tricorynus sp., habitus in dorsal view. Scale-bars: 500µm.

FIGURE 7. Erythematous papular lesion that resulted from a S. chicomendesi n. sp. sting.