Auxicerus magnipunctatus, Perger & Grossi & Guerra, 2017

Perger, Robert, Grossi, Paschoal Coelho & Guerra, Fernando, 2017, Description of a new species of the stag beetle genus Auxicerus Waterhouse, 1883 (Coleoptera: Scarabaeoidea: Lucanidae), European Journal of Taxonomy 302, pp. 1-10 : 6-7

Auxicerus magnipunctatus sp. nov.

urn:lsid:zoobank.org:act:5BB0BCE7-A060-45E2-AD54-FD2882697754

Fig. 2 D–E

Differential diagnosis

Auxicerus magnipunctatus sp. nov. is distinguished from all congeners by the posterior end of the ocular canthus being rounded and the anterior edge of the canthus moderately developed into an obtuse tooth; distance between apex of teeth as wide as distance between outer eye margins ( Fig. 2E ). Antennomeres 2–6 subquadrate, last two joints of club wider than long; lamellae not widely separated from each other ( Fig. 2E ). Punctures of mesosternum larger; mesosternum concavity weak.

Etymology

The species epithet is derived from the Latin ‘magna’ (large) and the Latin ‘punctatus’ (punctures), in reference to the large punctures all over the body.

Material examined

Holotype

BOLIVIA: ♂, labeled: “ Bolivia / Tarija department / Arce province / S22°13′20 W64°36′03 / 1049 m a.s.l. / mountain slope / Tucuman-Bolivian subhumid forest / midstorey vegetation / beating tray / 15-I- 2012 / R. Perger and F. Guerra leg.” ( CBF).

Description

BODY. BL 10.7 mm, BW 3.6 mm. Body compressed, dorsal surface reddish-black to brownish-black, almost glabrous with scattered scale-like setae on mandibles, head, pronotum and elytra; densely and strongly punctate. Venter brownish-black.

HEAD ( Fig. 2E ). Shape transverse, with large ocellate punctures, on disc and near eyes with a scale-like seta in each puncture; ocular canthus posteriorly intruding over anterior ¼ of eye, posterior canthus rounded; anterior edge of canthus moderately developed into obtuse triangle, distance between apices of canthi as wide as distance between outer eye margins; temporal process weakly pronounced as a tiny tubercle. Mandibles apparently symmetric, as long as head length, and sickle-shaped; inner dorsal surface with large punctures, near base with scattered scale-like setae; basal half with dorso-lateral carina, inner base with 3 teeth, 2 distinct at base, the apical tooth near obsolete; apex acuminate, and slightly upturned.

ANTENNAE. With scape as long as head midline length, flexuous; 2–6 antennomeres, subquadrate, short; pedicel distinctly longer than 3–6 antennomeres alone; club with lamellae not widely separated; last two joints of club wider than long, short, apical half of lamella pubescent.

PRONOTUM. Shape subtrapezoidal, lateral borders crenulated; sides lined by scale-like setae, especially near lateral and posterior angles; pronotal disc dark brown, shiny, moderately punctate, punctures large, decreasing in size to sides; longitudinal furrow, anteriorly and posteriorly, with scale-like setae interrupted at middle; sides reddish-black, weakly sinuous just before posterior emargination; anterior angles acute, projecting forward; lateral angles near straight; posterior angles distinctly sharp.

ELYTRA. Surface shiny, almost completely punctate, except for a rounded, opaque medio-lateral area surrounded by scale-like setae; punctures large, becoming coalescent near humeri, opaque area and elytral apex; borders except suture with similar setae, and near epipleuron setae more scattered. Scutellum obtusely rounded posteriorly, with small setose punctures mainly on disc.

LEGS. Surface of each tibia covered with a longitudinal row of erect, white setae; outer apical border of all tibiae produced into obtuse tooth; outer apical half of protibia with four larger teeth, between them smaller, rounded reddish-black teeth; mesotibia possesses one weakly developed outer tooth.

A comparison of the male genitalia is not included in the description because the holotype is too fragile to be rehydrated and dissected after its storage in ethanol and subsequent drying.

Comparisons

The other species of Auxicerus differ from A. magnipunctatus sp. nov. as follows: punctures on head finer; second to sixth antennomeres slender, about twice as long as wide; lamellae widely separated. All examined specimens of A. platyceps , including males smaller than A. magnipunctatus sp. nov., have a distinctly pronounced acute anterior edge of the ocular canthus (moderately developed into an obtuse tooth in A. magnipunctatus sp. nov.). Assuming that these characteristics vary in A. aethiops in the same range as in A. platyceps , it is likely that smaller individuals of A. aethiops also have a more prominently developed anterior edge of the ocular canthus than A. magnipunctatus sp. nov.

Geographical distribution

This new species is currently known only from the type locality ( Fig. 1 ). Despite further efforts by RP and FG to collect more individuals in other locations of the Tucuman-Bolivian forest in the last four years, no other specimens have been found. Nevertheless, A. magnipunctatus sp. nov. likely occurs as well in a similar habitat (Sub-Andean humid Tucuman-Bolivian forest) along the eastern slope of Chuquisaca and Tarija Departments ( Bolivia) to the Jujuy, Salta, Tucuman and Catamarca departments ( Argentina).

Figures

Fig. 2. A–B. Auxicerus platyceps Waterhouse, 1883. A. Holotype, ♂, BL 13 mm (BMNH). B. Head, ♂, BL 11 mm, Bolivia, Consata (EPCG). — C. Auxicerus aethiops Jakowleff, 1900, holotype, ♂, BL 16 mm, Bolivia (ZIRAS). — D–E. Auxicerus magnipunctatus sp. nov., holotype, ♂, BL 10.7 mm (CBF). D. Dorsal habitus. E. Head. Diagnostic characters indicated by arrows: (1) ocellate punctures on mesosternum, (2) posterior end of ocular canthus, (3) anterior edge of ocular canthus and (4) antennal lamellae. Scale bars: A, C–D = 5 mm; B, E = 2.5 mm.

Fig. 1. A. Bolivian records of Auxicerus platyceps Waterhouse, 1883 (open circle, solid rectangle); Auxicerus multicolor (Boileau, 1897) (open rectangle, solid rectangle) and Auxicerus magnipunctatus sp. nov. (solid circle). Localities: (1) Consata, (2) Caranavi, (3) Coroico, Chairo, (4) Los Volcanes and (5) Emborozu. B. Habitat of Auxicerus magnipunctatus sp. nov. in humid Tucuman-Bolivian forest.