Scaptorus pyramus, Caterino, Michael S. & Tishechkin, Alexey K., 2014

Caterino, Michael S. & Tishechkin, Alexey K., 2014, New genera and species of Neotropical Exosternini (Coleoptera, Histeridae), ZooKeys 381, pp. 11-78 : 35-36

Scaptorus pyramus sp. n. Figs 13-15, Map 2

Type locality.

FRENCH GUIANA: Belvèdére de Saül [3.01°N, 53.21°W].

Type material.

Holotype male:GUYANE FRANÇAISE: Belvèdére de Saül, point de vue. 3°1'22"N, 53°12'34"W. Piège vitre 31.xi.2010. SEAG leg." / "Caterino/Tishechkin Exosternini Voucher EXO-01763" (MNHN). Paratypes (6): 5: same data as type, except 2: 24.i.2011, 2: 10.xii.2010, 1: 17.i.2011; 1: Rés. des Nouragues, Camp Inselberg, 4°05'N, 52°41'W, 8.x.2010, FIT, SEAG (CHND, FMNH, MSCC).

Other material.

1: ECUADOR:Orellana, Yasuní Res. Stn. on mid. Rio Tiputini. 0°40.5'S, 76°24'W, FIT, 23-30.vi.1999, A.Tishechkin (LSAM), 1: 28. vi– 5.vii.1999 (LSAM). 1: PERU:Loreto: Campamento San Jacinto, 2°18.75'S, 75°51.77'W, 175-215m, 7.vii.1993, FIT, R. Leschen (SEMC); 1: Madre de Dios: CICRA Field Station, 12.55261°S, 70.11008°W, 295m, 11-13.vii.2010, blue pan trap, Chaboo Team (SEMC). 1: BRAZIL: Pará: Tucuruí, 3°45'S, 49°40'W, FIT, 27.x-9.xi.1985 (CHND); Melgaço Dist., Rio Marinau, 1°51.5'S, 51°20'W, FIT, 29.x-13.xi.1993 (CHND).

Description.

Size range: Length 2.2-2.5 mm; width 1.9-2.1 mm; Body: body rufobrunneus, elongate, sides subparallel, distinctly convex. Head: frons nearly as long as broad, more or less flat, weakly depressed in middle, sides widened very slightly to rounded anterior corners produced over antennal bases; frontal stria fine, present close to sides and along anterolateral edges, absent from middle; supraorbital stria absent; frontal disk with fine but conspicuous ground punctation throughout, with few coarser punctures along dorsal margin, faintly microsculptured; epistoma bituberculate along anterior margin, tubercles subtended by weak carinae to ends of frontal stria, epistomal disk depressed along midline; labrum about one-third as long as broad, apical margin truncate, weakly produced and carinate above flattened supraoral surface. Pronotum: pronotal sides subparallel in basal two-thirds, abruptly bent to apical corners; pronotal gland openings not evident; marginal stria complete along lateral and anterior margins; sinuate, transverse elevated carina present one-fourth behind and parallel to anterior pronotal margin, curving posterad briefly at sides, abruptly bent to lateral margin one-third from anterior corner; ground punctation of disk fine posterad carina, markedly denser anterad carina, with few coarser, shallow punctures at sides; prescutellar impression absent. Elytra: convexity of elytra slightly greater than that of pronotum, i.e., lateral profile not a smooth curve; epipleuron smooth, with single, complete marginal stria; outer subhumeral stria carinate, forming distinct lateral margin to dorsal surface, inner subhumeral stria present only in basal half, striae 1-4 complete, 5th stria obsolete in basal one-third, rarely complete, sutural stria obsolete in basal one-third; all dorsal striae rather shallowly impressed, but 4th, 5th and sutural striae broad, at least apically, delimited on inner and outer edges. Prosternum: prosternal keel overlapped at base by projecting mesoventrite, lacking carinal striae, weakly convex, short, anteriorly displaced by prominent prosternal lobe, which is strongly produced, deflexed, with raised median ridge, marginal stria absent. Mesoventrite: mesoventrite subtrapezoidal, narrowed, projecting anteriorly, lacking marginal stria; mesometaventral stria absent. Metaventrite: postcoxal stria present, curved around mesocoxa to middle of mesepimeron; lateral metaventral stria extending from inner corner of mesocoxa toward middle of metacoxa, bent laterad apically toward metepisternum; metaventral punctation fine and sparse at middle, with few coarser punctures at sides. Abdomen: 1st abdominal ventrite with ground punctation rather dense, with parallel lateral striae along inner edge of metacoxa; ventrites 2-4 simply punctate, lacking transverse striae; propygidium wide, rather short, with small gland openings in anterolateral corners; pygidium about one third wider than long, apical margin simply rounded. Legs: protrochanter lacking setae, meso- and metatrochanters with pair of very short setae near apex of posterior edge; profemur rather narrow, anterior edge sinuate, partial stria along posterior margin; protibia narrow at base, outer margin widened to more or less rounded apical half, weakly dentate, each tooth bearing thin but rather long spine; protibial spurs present, short; protarsus somewhat laterally compressed, bearing spatulate ventral setae in both sexes; meso- and metafemora narrow, slightly elongate; meso- and metatibiae slightly widened to apices, bearing few thin spines toward apex of outer margins. Male genitalia (Fig. 15): Paired accessory sclerites present; T8 with broad basal and narrower apical emarginations, line of basal membrane attachment complete, distad basal emargination, ventral apodemes well developed, nearly meeting along midline; S8 with halves nearly meeting only at base, divergent apically, apical guides well developed from base to near apex, rather abruptly narrowed to subacute apex, each side with single inconspicuous subapical seta; T9 with broad, blunt ventrolateral apodemes, apices narrow, obliquely subtruncate; T10 completely divided; S9 broad, truncate at base, narrowed toward apex, head broad, with prominent lateral flanges, apical flange low, continuous, not interrupted medially; tegmen rather narrow, widest at middle, evenly narrowed to base and apex, weakly curved in lateral aspect, lacking medioventral tooth or process; basal piece about one-third tegmen length; median lobe almost half tegmen length, gonopore rather wide, basal processes strongly differentiated, with thin proximal arms over half overall length.

Remarks.

The majority of specimens of this unusual species appear to bear witness to some interesting aspect of its biology. Most show distinct longitudinal scratches on the pronotal disk behind the transverse carina (Fig. 14B). What might be causing this is unclear, but we would suggest ant mandibles as a possibility. We limit the type series to those specimens from French Guiana, due to the lack of males from other localities with which to confirm identity.

Etymology.

The name of this species refers to pyramidal swellings on the apex of the epistoma.