Crenulister impar, 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 : 56-59

Crenulister impar sp. n. Figs 23A, 24, Map 5

Type locality.

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

Type material.

Holotype male: "GUYANE FRANÇAISE: Bélvédère de Saúl, point de vue. 3°1'22"N, 53°12'34"W. Piège vitre, 2.ix.2011. SEAG leg." / "Caterino/Tishechkin Exosternini Voucher EXO-03016" (MNHN). Paratypes (12): 1: same locality as type, 20.xii.2010 (CHND); 4: FRENCH GUIANA: Rés. Natur. des Nouragues, Camp Inselberg, 4°05'N, 52°41'W, 30.ix.2010, FIT, SEAG (MNHN, CHND, FMNH, MSCC), 1: 20.viii.2010 (LSAM), 1: 22.ix.2010 (CHND), 1: 9.xi.2010 (CHND), 1: 25.i.2011 (CHND), 1: 8.x.2010 (CHND); 1: Matoury, 41.5 km SSW on Hwy N2, 4°37'22"N, 52°22'35"W, 50m, 26-28.v.1997, J. Ashe & R. Brooks, FIT (SEMC). 1: GUYANA:Cuyuni-Mazaruni: Kartabo, 24.ix.1920, W.M.Mann (USNM).

Other material.

1: PERU:Madre de Dios: Tambopata, Reserva Cuzco Amazonico, 15km NE Pto. Maldonado, 12°33'S, 69°03'W, 200m, 22.vi.1989, FIT, J. Ashe & R. Leschen (SEMC), 1: 24.vi.1989 (SEMC); 1: Loreto: 1.5km N Teniente Lopez, 2°35.66'S, 76°06.92'W, 210-240m, 20.vii.1993, FIT, R. Leschen (SEMC); 1: Cusco: Villa Carmen Field Station, 12.8925°S, 71.4192°W, 24-26.v.2011, FIT (SEMC). 1: BRAZIL:Mato Grosso, Cotriguaçu, Fazenda São Nicolau, Matinha, 9°50.3'S, 58°15.05'W, xii.2009, FIT, F.Z. Vaz-de-Mello (CEMT). 1: ECUADOR:Orellana: Tiputini Biodiversity Station, 0.6376°S, 76.1499°W, 4-9.vi.2011, FIT, M.S. Caterino & A.K. Tishechkin, DNA extraction voucher MSC-2129 (MSCC).

Diagnostic description.

Length: 1.8-2.2 mm, width: 1.6-2.0 mm; as for generic description with the following diagnostic characters: body rufescent to rufobrunneus, elongate ovoid, subdepressed; frontal stria fine, usually complete, rarely narrowly interrupted, frontal disk moderately depressed, with fine but relatively dense punctation consisting of ground punctation and barely larger secondary punctation; epistoma with lateral ridges delimiting median depression bearing weak lateral striae basally; labrum about 4 × wider than long, apical margin weakly emarginate; pronotum with gland opening track reaching approximately to midline, with 3-4 openings along its length; pronotal sides with crenulate, slightly elevated lateral submarginal stria; pronotal disk with small secondary punctures conspicuous in basal half, as well as at sides, anteromedial portion of disk with only fine ground punctation; weak prescutellar impression present; elytron with one complete, crenulate epipleural stria rather distant from margin, especially posteriorly, all dorsal striae complete, shallowly but coarsely impressed; all elytral interstriae sparsely, irregularly punctate, with 18-30 secondary punctures, generally more in the 5th-sutural interval; prosternal keel deeply emarginate at base, carinal striae complete, narrowly united anteriorly; prosternal lobe slightly deflexed, marginal stria present only at middle; mesoventrite with marginal stria fine to weakly crenulate, mesometaventral stria crenulate, angulately arched forward to basal third of mesoventral disk; postmesocoxal stria recurved anterad around mesocoxa, ending short of mesepimeron; lateral metaventral stria crenulate, ending short of metacoxa; metaventral disk punctate throughout, secondary punctures slightly smaller and sparser anteromedially; metepisternal punctures coalesced into distinct stria; lateral stria of 1st abdominal ventrite present along inner edge of metacoxa, curving laterad behind metacoxa, occasionally interrupted; secondary punctures of median portion of 1st abdominal ventrite larger and denser in basal half, with slightly oblique punctures toward sides behind metacoxa; punctures along posterior margins of ventrites 1-4 transversely elongate, intermittently coalesced into marginal strioles; protibia ~6-7-spined, with marginal dentation weak; meso- and metatibia with 3-5 thin, elongate spines, mainly along apical half of margin; propygidium with secondary punctures shallow but rather large, fairly uniformly separated by about their diameters throughout; pro pygidial gland openings very faintly tuberculate in anterolateral corners, propygidial strioles absent; pygidium with sparse secondary punctation mainly along sides; pygidial gland openings evident near sides about one-fourth from base; pygidial margin with striae along most of apical two-thirds, usually interrupted at apex. Male (Fig. 24): accessory sclerites absent; T8 with ventrolateral apodemes strongly narrowed beneath; S8 short with halves meeting only at basal corner, inner margins short and strongly divergent, with 6-8 strong setae toward apex; T9 with apices obliquely truncate; T10 weakly emarginate at apex; S9 quadrate at base, apex emarginate; tegmen widest in apical third, apex more or less rounded, apices slightly separated, medioventral process produced beneath about one-third from base; median lobe short, basal piece about one-third tegmen length.

Remarks.

This species is somewhat difficult to characterize, in part because there's, relatively more material than for most, from a wider area, and individual variation is accordingly more evident. Among the smaller, more rufescent species of the genus, the complete elytral striae (Fig. 23A), presence of distinct secondary punctures on most of the basal half of the pronotal disk, the pronotal gland track reaching to the pronotal midpoint, and the presence of (usually) well developed marginal pygidial striae will generally distinguish it. The apically widened aedeagus (Fig. 24E) is distinctive, and consistent among males examined. However, we restrict the type locality to the Guianas due to some uncertainty about species assignment of all populations. Additional material from the southern and Andean parts of the range may reveal more consistent patterns of external variation and justify further splitting.

Etymology.

This species’ name refers to the ‘unequal’ distribution of pronotal punctures, distinctly increasing in density posterad.