Metallactus sekerkai Sassi, 2015

Sassi, Davide, 2019, Revision of the Metallactus hamifer species-group (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 4657 (2), pp. 201-245 : 236-238

Metallactus sekerkai Sassi, 2015

( Figs 15 ; 32 )

Metallactus sekerkai Sassi, 2015: 704 .

Types. HOLOTYPE: ♂, glued, aedeagus glued on the same card bearing the specimen // “ Bolivia, Santa Cruz dpt., Florida pr. 1050-1150m Refugio Los Volcanes 18°06.3’ S 63°26.0’ W beating of vegetation L. Sekerka lgt. 10-14 xii 2011 ” [white label, printed] // “ Metallactus sekerkai sp. nov . HOLOTYPUS D. Sassi des.” [red label, printed] // ( NMPC). PARATYPES: 2♂ 2♀, same data as the holotype, all provided with additional label: “ Metallactus sekerkai sp. nov . PARATYPUS D. Sassi des.” [red label, printed] // ( NHMP, LSPC, DSPC) .

Type locality. Refugio Los Volcanes (Florida Province, Santa Cruz Dept., Bolivia) .

Distribution. Bolivia.

Further material examined. BOLIVIA: Achira Santa Cruz rd to Floripondo 1900m Leg. Bonaso Morris & Wappes (2, NHMP) ; Achira Santa Cruz Dept. Florida Prov. 1999m 25.xi.2013 Leg . A. S. Konstantinov (1, USNMNH) ; Samaipata Santa Cruz Dept. Florida Prov. 1662m 30.xi.2013 Leg . A. S. Konstantinov (2, USNMNH) .

Diagnosis. A Metallactus of medium-large size. The species belongs to the subgroup with longitudinal dorsal color pattern. It resembles M. albivittis because of the dorsal overall light hue in which only yellow and reddish are present wereas black or dark brown patches are totally lacking. However, M. albivittis shows two longitudinal reddish lines on elytron (only one, much larger in M. sekerkai ). Besides, M. albivittis has narrower, less transverse pronotum with stronger and closer punctuation. Median lobe of aedeagus is different as well.

Description of male. Habitus in Fig. 15 a–b (HT). BL = 5.1–5.5 mm, BW = 2.9–3.2 mm, PL = 1.7–1.9 mm, PW = 2.6–2.8 mm. Interocular distance 9.1–9.8% of BL.

Head yellow with reddish patches on vertex, insertion of antennae and lower part of clypeus. Vertex rather convex, sparsely and rather shallowly punctured with scattered, short setae. Frontoclypeal area coarsely punctured, generally more densely arranged along inner ocular rim. Mid-cranial suture long, very distinctly impressed so that surrounding surface looks slightly swollen. Antennae black, only apex of first five antennomeres yellowish.

Pronotum yellow with two longitudinal reddish band, slightly angulate on inner rim, extending from apical to basal margin. Pronotal shape tronco-conical, rather lengthened. Sides only slightly arcuate, so that lateral margin are completely visible from above. Posterolateral impressions obliterated so that posterior margin not salient behind them. Surface regularly convex with punctation well impressed and sparse above all on sides.

Scutellum dark yellow to red toward apex, bald, distinctly raised, with apex subtruncate.

Elytron yellow with two large longitudinal reddish bands extended from base toward apex, in continuity with that ones on pronotum. Bands are sligthly concave on outer sides, tapered posteriorly and not reaching apex. Suture narrowly darkened. Elytral outline parallel-sided, lengthened, weakly flattened on disc. Postscutellar area regularly even, namely, not raised in shape of tubercle. Humeral callus scarcely prominent, impunctate. Surface moderately shiny with punctation fairly impressed, arranged in quite regular rows, slightly less impressed towards apex, rows are barely recognizable on periscutellar area and behind humera; Intervals flat.

Pygidium yellow, rather lustrous, covered with sparse shallow punctures and whitish semi-erect setae.

Inferior parts of thorax totally reddish. Hypomera coarsely and sparsely punctured, bare. Mesoepimera and mesoepisterna almost bare with shallow punctures. Metaepisterna and metasternum with irregular punctation and wrinkles, bearing sparse setae. Prosternal process coarsely punctured with long setae and raised, short, pointed triangular apex. Abdominal ventrites reddish with large marginal yellow band, sparsely, minutely punctured and with sparse, whitish setae. Legs reddish with apex of tibiae and tarsi black.

Median depression on fifth abdominal ventrite shallow but well delimited from rest of ventrite surface. Posterior margin of fifth abdominal ventrite visibly notched. Median lobe of aedeagus ( Fig. 15 c–e) cylindrical with apex scarcely separated from the rest of aedeagus, short, blunt. In lateral view apex faintly bent ventrally. Hairy dents scarcely impressed, rather lengthened, barely delimited but bordered below by a shallow depression, bearing rather long, dense, straight setae. Aedeagal ventral surface clearly swollen in lateral view, with a couple of shallow depression just below hairy dents, delimiting a faint and short median carina. Endophallus ( Fig. 15f ) with sclerite I robust, stout, with denticle apparent, blunt, forwardly directed and perceptibly sticking out laterally. Dorsal spicule well developed, slightly swollen, obtuse. Sclerite II well developed, abruptly bent at base and gradually tapered towards apex. Arch of sclerite III slender, scarcely raised. Apex of sclerite III straight and gradually pointed, slightly expanded on its proximal half, so that the sclerite looks like the head of a grebe. Branches of sclerite IV shorter than sclerite III in the folded-up structure, straight and relatively slender at basal half but distally broadened in a large, saddle-like, asymmetrical, microdenticulate apex. Surface of branches perceptibly rugose.

Female. BL = 5.9–6.7 mm, BW = 3.5–3.8 mm, PL = 1.7–2.1 mm, PW = 2.0– 3.3 mm. Interocular distance 12.1–13.6 % of BL.

Fifth abdominal ventrite in females with a deep, slightly transverse pit. Bottom of pit bald, matt, impunctate. Vasculum of spermatheca ( Fig. 15g ) scarcely pigmented with proximal branch faintly bent at base, long distal branch gradually tapered in a moderately pointed apex, slightly bent downwards. Ampulla not pigmented, lengthened, sticking out from basal rim of proximal branch, therefore not shifted on dorsal side of vasculum. Duct insertion and sperm gland insertion perceptibly distinct. Duct uniform in size, slender, coiled with coils rather thick, rather regularly arranged. Distal not coiled portion of duct long, minutely winding. Insertion on bursa copulatrix lengthened, S-shaped, barely swollen, moderately pigmented.

Figures

FIGURES 14–15. M. praetorius (14), M. sekerkai (15). 14a–b: habitus; 14c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.6 mm]; 14f: sclerites of endophallus [0.4 mm]; 14g: spermatheca [0.5 mm]; 14h: antenna [1.6 mm]. 15a–b: habitus; 15c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.9 mm]; 15f: sclerites of endophallus [0.5 mm]; 15g: spermatheca [0.9 mm]; 15h: antenna [1.9 mm]. 14a–b: holotype; 15a–b: holotype. scI–IV: sclerites I–IV of endophallus; ds: dorsal spicule. Square brackets: length of scale segment.

FIGURES 27–34. Distribution maps for Metallactus hamifer species-group. M. luniger (27); M. madefactus (28); M. octoguttatus (29); M. pollinctor (30); M. praetorius (31); M. sekerkai (32); M. tarsalis (33); M. viator (34). Grey squares: localities reported in a generic way.