Pselactus strakai, Batelka, 2017

Batelka, Jan, 2017, Review of Cape Verde Pselactus Broun, 1886 (Coleoptera: Curculionidae: Cossoninae) with description of a new species, larvae and notes on biology, Zootaxa 4317 (2), pp. 225-246 : 234-237

Pselactus strakai sp. nov.

( Figs 6 A–B, 7A–E, 8C–D, 9B, 10B, 11A–F, 12A–D)

Adult material studied. HOLOTYPE, Ƌ: CAPE VERDE Isl., SAO NICOLAU, E, Tope de Chuva, 10.XI.2011, 16o36’6.05”N, 24o7’26.8”W, J. Batelka & J. Straka lgt. / IN ROTTEN STALKS OF EUPHORBIA . (SMNS). PARATYPES: 232 ex; 217 ex: the same data as holotype; 14 ex: CAPE VERDE Isl. , SAO NICOLAU, W, S of Cachaco, 13.XI.2011, 16o37’N, 24o7’21”W, J. Straka & J. Batelka lgt. / IN ROTTEN WOOD OF JATROPHA SP . - FIELDS; 1 ex CAPE VERDE Isl. , SAO NICOLAU, Alto das Cabacas mts., 6.X.2013, 16.599716 N, 24.103952W, J. Straka & J. Batelka lgt. / IN ROTTEN STALKS OF EUPHORBIA . (5 ex NHMUK, 164 ex CJB (deposition in SMNS is expected), 20 ex CJS, 20 ex CPH, 2 ex CMNC, 2 ex DEI, 2 ex HNHM, 2 ex MNCN, 2 ex MNHN, 2 ex MMBC, 2 ex NHRS, 5 ex NMPC, 2 ex NMW, 2 ex OUMNH).

Diagnosis. Antennal scape slightly pedunculate at apex, long, slightly shorter than funicule, funicule with 7 antennomeres; antennomere II slightly longer then wide, at apex wider than apical width of antennomere III, antennomere III 1.3 times as long as II; antennal club twice as long as wide; head and pronotum smooth, very finely shagreened, with dense and even punctation, space between punctures varies, always greater than the diameter of a puncture; anterior margin of pronotum clearly narrower than base; pronotum widest in posterior half; elytral intervals flat; elytra wide, shiny, with ten striae formed by small punctures.

Description ( Figs 6 A–B, 7A–E, 8C–D, 9B, 10B). Body convex, shiny, pitchy-black, tarsi and antennae brownish ( Figs 6 A–B). Length 4.10–5.90 mm, maximal width of elytra 1.90–2.30 mm.

Head with sparse punctures, rostrum slightly convex, 0.60–0.80 mm long, about 3.00–3.30 times as long as head behind eyes; antennal scrobe lateral, curved downward before eye, well-defined, deep, the point of antennal insertion located on middle of rostrum ( Figs 8 C–D); antennae slender, with long, sparse setae, antennal club with dense, golden pubescence; antennal scape long, pedunculate at apex, about 5 times as long as antennomere II and slightly shorter than funicule; funicule with seven antennomeres, first stout, second expanded to apex, 1.30–1.40 times as long as first, funicular antennomeres III–V subequal, transverse, VI–VII transverse, larger than III–V, antennal club with three antennomeres, apically pointed, 1.80–1.90 times as long as wide; eyes oval, flat, transverse diameter of eye about 1.30 times as long as distance from margin of eye to pronotal margin ( Figs 8 C–D).

Pronotum ( Fig. 9 B) with dense punctures, pronotal punctures clearly larger than punctures on head, distance between punctures varies but always superior to diameter of punctures, 1.05–1.15 times as wide as long, 1.30–1.40 times as long as head, widest behind middle, basal margin arcuate, posterior part wider than anterior one. Scutellum absent.

Elytra ( Fig. 10 B) strongly convex, fussed, surface smooth and shiny, in anterior part elytra transversally wrinkled, elytral intervals flat, very large, with ten striae formed by small punctures, distance between punctures at least twice of diameter of a puncture, humeri prominent. Hind wings absent.

Prosternum strongly punctured, narrow, procoxae contiguous, hypomera separated by hypomeral ridges which form prosternal process; mesoventrite very short, about 3 times shorter than metaventrite, both shagreened and with uneven punctures, metaventrite with entire median furrow, mesocoxae separated, metacoxae strongly separated by large process of first ventrite, punctures on metaventrite much stronger than those on first ventrite, ventrite I about 1.60 times as long as second, puncturation on ventrites I and II similar, ventrites I and II strongly shagreened with sparse punctures, ventrites III and IV subequal in length, finely shagreened, more glossy than I and II, with one row of punctures, ventrite V glossy, with dense punctures.

Legs ( Figs 6 A–B) brownish, shiny, tibiae with strongly arcuate uncus and small mucro, apex with golden setae, tarsus with five (apparently four) tarsomeres, tarsomere I long, II short, III bilobed, onychium about as long as tarsomere I, with two equal tarsal claws.

Male genitalia. Aedeagus ( Fig. 7 A), male sternite 9 (spiculum gastrale) ( Fig. 7 B).

Female genitalia. Spermatheca ( Fig. 7 E), female sternite 8 (spiculum ventrale) ( Fig. 7 C), gonocoxites ( Fig. 7 D).

Sexual dimorphism. Not apparent, but females slightly larger than males.

Differential diagnosis. Pselactus strakai is distinguishable from its congeners by the combination of the following character states: 1) body smooth, lacking setation or at most with minuscule setae ( Figs 6 A, 10B); 2) scutellum absent or minuscule ( Fig. 6 A); 3) pronotum smooth or very finely shagreened ( Fig. 10 B). Only P. caulius Wollaston, 1861 and P. piceus Wollaston, 1861 meet this combination of characters ( Folwaczny, 1971), both are endemic and widely distributed on the Canary Islands (La Gomera, La Palma, El Hierro, Tenerife). P. caulius differs from P. strakai having pronotum with rough, dense puncturation. From P. piceus which has pronotum with fine punctures, P. strakai differs by larger body size, totally absent scutellum and tarsomeres III strongly enlarged and bilobed (for diagnosis of P. piceus see Folwaczny, 1971: 180). Pselactus strakai is readily separated from P. obesulus by different surface pattern of pronotum and elytra. Punctures on pronotum in P. strakai small, distance between punctures varies but always superior to diameter of punctures ( Fig. 9 B), punctures in P. obesulus large, distance between punctures, especially on disc, much inferior to diameter of punctures ( Fig. 9 A); elytra with small, but well-defined and separated punctures forming ten striae, striae evanescent on sides and punctures weakly separated ( Fig. 10 B), almost touching on anterior part of elytral disc in P. obesulus ( Fig. 10 A).

Etymology. Patronymic, named after Dr. Jakub Straka, a well-known Czech Hymenopterist and the cocollector of type specimens.

Figures

FIGURE 6. Pselactus strakai sp. nov., habitus, male, holotype: A—dorsal view, B—lateral view.

FIGURE 7. Pselactus strakai sp. nov., male genitalia: A—aedeagus, dorsal and lateral view; B—male sternite 9 (spiculum gastrale); and female genitalia: C—female sternite 8 (spiculum ventrale), D—gonocoxites, E—spermatheca. Scale bars: 0.1 mm.

FIGURE 8. Pselactus obesulus, rostrum, male, lectotype: A—lateral view, B—dorsal view. Pselactus strakai sp. nov., rostrum, male, holotype: C—lateral view, D—dorsal view.

FIGURE 9. Pronota of Pselactus species, males: A— Pselactus obesulus, lectotype, B— Pselactus strakai sp. nov., holotype.

FIGURE 10. Elytra of Pselactus species, males: A— Pselactus obesulus, lectotype, B— Pselactus strakai sp. nov., holotype.