Corimalia strejceki Schön & Skuhrovec, 2016

Schön, Karel & Skuhrovec, Jiří, 2016, A new species of the genus Corimalia Gozis, 1885 (Coleoptera: Brentidae: Nanophyinae) from the Caucasus, Zootaxa 4169 (3), pp. 571-578 : 572-576

Corimalia strejceki Schön & Skuhrovec , sp. nov.

( Figs 1, 3 , 5–8 , 13 )

Material examined. HOLOTYPE: ♂, Tamarix sp. [handwritten] / USSR - Caucasus centr., Teberda, 1500 m, 11.6.1986, J. Strejček lgt. [printed] / c/11-30 [handwritten] (NMPC). PARATYPES: 1 ♂ and 3 ♀♀, Tamarix sp. [handwritten] / USSR - Caucasus centr., Teberda, 1500 m, 11.6.1986, J. Strejček lgt. [printed] / c/11-30 [handwritten] (2 ♀♀ JSCP, 1 ♂ and 1 ♀ KSCL); 1 ♂, Tamarix sp. [handwritten] / USSR - Caucasus centr., Teberda, 1500 m, 14.6.1986, J. Strejček lgt. [printed] / c/11-30 [handwritten] / Gen.? cf. Corimalia, J. Strejček det. 2011 [handwritten] (JSCP); 1 ♂ and 1 ♀, Ca. Kislovodsk, V. 912, Roubal [printed] / N. languidum. [handwritten] (JSCP). All specimens are provided with additional red printed label: HOLOTYPUS [or PARATYPUS, respectively], Corimalia strejceki sp. n., K. Schön design. 2015

Description. ( Figs 1, 3 , 5–8 , 13 ). Body length without rostrum 2.92–3.25 mm. Colouration of body and legs testaceous; antennae yellow-orange; club dark brown to black apically; head (except forehead), rostrum, pronotum, elytral suture, dorsal side of femora, apical part of teeth on femora in males, distal part of tibia and tarsomeres to varying degrees dark brown to black. Ventral part of body dark brown to black with the exception of last abdominal sternite and pygidium testaceous. Colouration, however, also dependent on the degree of sclerotization (e.g., specimens from Kislovodsk mostly tawny with less intense darkening of above mentioned parts of body). Body and extremities covered with narrow piliform scales of differing densities. Head covered with piliform scales especially on forehead and temples, completely covering integument, underside of head contrasting smooth and shiny. Funicle segments 1–5 with infrequent suberect setae, funicle segment 6 apically covered with short adjacent cilia at high density; club covered with cilia as funicle segment 6. Pronotum in middle with narrowing stripe of whitish slightly thicker piliform scales from apical to basal margin; sides of pronotum also with high density of piliform scales, partly with white scales at level of humeral angles, or below with narrower goldish scales; disk of pronotum also with goldish coloured, but finer, scales. Base of elytral intervals 1 and 2 with adjacent piliform scales in high density (roughly as on pronotum) creating a rectangular patch as long as six widths of interval 2; some specimens without scales in interval 1 at base of elytra, and with distinct baldness; humeral angles also covered by scales in high density; intervals with several rows of softer scales, somewhat stronger at elytral apex; scales not covering the integument, with the exception of a patch at the base of the elytra and humeral angles; interval 7 apically with one short distinct erect specialized seta. Femora and tibia except their apices covered by adjacent, softer hairlike scales, not overlapping the integument. Dorsal part of tarsomeres covered by narrow bristles, sides of tarsomeres I and II particularly with longer, stronger bristles, bent downward toward to bottom side thereof, giving the impression of "spined" margins of the ventral side of tarsomeres I and II.

Head ( Figs. 1, 3 ). Rostrum long; in dorsal view, sides straight from base to apex, sometimes only slightly enlarged in area of antennal insertion; dorsum of basal part shagreened, then central fine keels on its sides with one or two rows of oval punctures; between dorsal margins of antennal scrobes and described dorsal structures of rostrum, sometimes plain area extending from base of rostrum as a slender flatter keel extending further dorsally, all these structures in the approximate area of the antennal insertions, or only shortly behind; thence towards apex of rostrum smooth, firstly in high density, then in lower density punctate with small oval punctures; dorsal margins of scrobes densely punctate, then prolonged by a line of the same punctures to apex, as on dorsal side of apex; in lateral view, scrobes stretching from base of rostrum up to antennal insertion shortly behind middle of rostrum, dorsal margin inserted at about half height of eye, ventral margin follows line of genae below eye, and continues up to antennal insertion; both delimiting margins parallel; interior of scrobes in particular at base of ventral margin densely granulate, then this granulation gradually disappearing to apex; lateral side behind scrobes smooth with several oval punctures. Head shortly conical (length from base of rostrum to margin of pronotum = 0.29–0.37 mm). Eyes round, not projecting beyond outline of head. Forehead wide, nearly as wide as half of apex of rostrum; connection with dorsal part of rostrum base at obtuse angle as is characteristic for tribe Corimaliini (Alonso- Zarazaga, 1989). Vertex short, behind eyes slightly sunken.

Antennae slender, inserted in middle of rostrum. Scape long (about 0.6 mm), slender, in short apical part clubshaped enlargement; about 0.7–0.8 times as long as a funicle and club together. Funicle segment 1 (pedicel) slender (0.14–0.19 mm in males, 0.16–0.19 mm in females); funicle segment 2 elongate, less than twice as long as pedicel, apically slightly enlarged; funicle segments 3–5 about equal length (from 0.16 to 0.19 mm in total), slender, towards club, with slightly club-shaped enlargement; funicle segment 6 again inverted conical with straight sides, slightly longer and slightly wider than funicle segment 5. Club three-segmented, elongated, spindle-shaped (0.27– 0.37 mm), as long as funicle segments 2–5 together, slender (width 0.10 mm in males, 0.08 mm in females).

Pronotum ( Figs. 1, 3 ) subconical, only slightly constricted behind apical margin (ratio (with apical margin) = 1.14–1.33, ratio (with basal margin) = 0.70–0.85; length 0.76–0.93 mm, width at apical margin 0.62–0.72 mm, basal margin 1.09–1.24 mm); sides slightly rounded; prescutellar fovea absent as characteristic for subfamily Nanophyinae ; basal margin slightly sinuous wavy, crenulate, with small but distinct dark teeth; surface finely, shallowly and densely punctate.

Elytra ( Figs. 1, 3 ) short, oval (ratio = 1.00–1.18, length 1.74–2.02 mm, width 1.61–1.86 mm); continuously tightened to base of pronotum, widest behind middle; distinct humeral angles, but only slightly convex; base of elytra slightly sinuous as well as base of pronotum, distinctly crenulate; striae narrow, shallow, without distinct punctures; intervals slightly convex, 2.0–2.5 times wider than striae.

Legs ( Figs. 1, 3 , 13 ). Femora strong, with one large proximal and two or three small distal teeth (count of small teeth different also on femora of one specimen). Tibiae nearly straight, apically outside perimeter of the tapered portion with high density apical comb of setae. Tarsomeres I and II about equal length, elongated triangular (ratio = 1.43–2.00); tarsomere III bilobed, short; onychium long, narrow (ratio = 5.00–6.67), apically with two simple claws.

Sexual Dimorphism. Rostrum in males slightly longer than pronotum, and in females almost twice as long as pronotum (ratio = 1.20–1.38 in males, 1.85–1.97 in females); in males 5.3–6.1 times, and in females 8.2–9.2 times as long as width of apex; and in females more finely punctured and particularly in apical half shinier than in males as typical for other Corimalia . Antennae inserted near middle of rostrum (0.56 in males, 0.46 in females). Apical inner margin in meso- and metatibiae in males extend into distinct triangular mucro, partly overlapped by extending apical comb of setae. Apex of meso- and metatibiae in females without mucrones.

Male genitalia. Penis ( Figs 5–6 ) symmetrical; relatively short and slender; in lateral view slightly curved, apex partially hooked, median part straight; pedon shorter than temones; apex elongated ( Fig. 8 ). Tegmen ( Fig. 7 ) with tegminal ring longer than free short tegminal apodeme; parameral plate subarticulated; apical plate divided by median notch in two very short parameroid lobes bearing long and numerous setae. Spiculum gastrale asymetrical as typical for Nanophyidae , manubrium very long; left arm distinctly more elongate; extensions present on both arms, but distinctly reduced.

Differential diagnosis. The tribe Corimaliini could be divided into several working groups on the basis of several morphological features (e.g., shape of elytral base, width of forehead, presence of mucro on meso- and metatibiae, and shape of apex of penis) ( Giordani-Soika 1937; Schön K., unpublished data). A set of these features identical to those expressed in Corimalia strejceki sp. nov. (forehead wide as half of width of rostrum, base of elytra crenulate, meso- and metatibia with mucro, and apex of penis symmetrical), is known for Corimalia aliena (Faust, 1890) ( Figs 2, 4 , 9–12 , 14 ) and also Corimalia helenae Korotyaev & Zherikhin, 1996 , which both are very similar also in colouration and shape of scales (lancet-shaped or more or less piliform) instead of Corimalia latifrons (Pic, 1897) , which is covered by white spindle-shaped scales (see Giordani-Soika 1937). The species Corimalia helenae is distinctly smaller (body length without rostrum 1.90–2.65 mm) than both species C. strejceki and C. aliena . The most similar species to the new described species is C. aliena differing in the following characters; size, shape of scales, scale patch close to the scutellum, size of mucrones on the meso- and metatibiae, and also shape of the apex of the penis. The described species C. strejceki is slightly larger (body length without rostrum 2.92–3.25 mm) than C. aliena (body length without rostrum 2.77–3.02 mm) and also slightly larger than any other Corimalia species. Scales of C. aliena are lancet-shaped (pointed on both sides), but scales of C. strejceki are more or less piliform with a point only on one side. However it must be noted that these conclusions were based on limited material (8 specimens of C. strejceki and 4 specimens of C. aliena ), and study of more material may modify those conclusions. Some small differences are visible also in the scale patch close to the scutellum; C. aliena has a significant baldness in the middle of the patch toward the base of elytra, while this is present in only a few specimens of C. strejceki . The mucrones on the meso- and metatibiae apically in males of C. strejceki are distinctly larger than those in males of C. aliena . These two species have distinct differences also in the shape of the apex of the penis, where apex of C. strejceki is distinctly tapered and more elongate than apex of C. aliena (see Figs 8, 12 ). Extensions on spiculum gastrale of C. alinea distinctly larger than extensions of C. strejceki .

Etymology. The species name honours a gentleman and prominent Czech coleopterologist, specialist in the families Curculionidae and Chrysomelidae sensu lato, Dr. Jaromír Strejček, who collected this species during his travels in Teberda.

Biology. Adults were collected by beating Tamarix sp. in meadows in the valley of a mountain river during a warm (ca 18°C) cloudy evening (ca 6– 7 p. m.). Tamarix specimens have distinctly large buds in June, and the size of the shrubs was no more than 1.5 metres tall (J. Strejček, pers. comm.).

Distribution. Russia: Caucasus centr., Teberda, Kislovodsk.

Morphological remarks. Voss (1960) erected the new subgenus Pseudocorimalia Voss, 1960 for two new species Corimalia exsanguis Voss, 1960 and Corimalia pilosella Voss, 1960 based on the following characters; sixsegmented funicle, three-segmented club with a vague final segment and elytra without humeral angles. Zherikhin (1972) listed Corimalia aliena (Faust, 1890) with either five or six segments in the funicle, and also observed that Voss (1964) presented a similar state, with variable number of segments in the funicle, for the species Corimalia discreta Voss, 1964 and Corimalia gyrata (Peyerimhoff, 1929) . Furthermore, Zherikhin (1972) listed that the variability in the count of segments in the funicle is widespread in the genus Corimalia Gozis, 1885 and denies the possibility of using this character to define subgenera. Alonso-Zarazaga (1989) in the key of Palaearctic taxa of the subfamily Nanophyinae noted unequivocally that species of the genus Corimalia have the funicle strictly with 5 segments, and in comments on this genus explains the sixth segment as the isodiametric first segment of the club, supported by its identical spots and vestiture to a club, but different from previous segments in the funicle. A threesegmented club and six-segmented funicle has been mentioned already by Reitter (1890) in the description of Nanophyes fausti (currently in the genus Corimalia ). This situation is also evident in other species, e.g. Corimalia aliena , C. helenae Korotyaev & Zherikhin, 1996 , C. chinensis (Faust, 1890) and others. On the other hand, species with a shorter and wider club (e.g. Corimalia postica (Gyllenhal, 1838)) have evidently only a five-segmented funicle. However, the evaluation of the affiliation of the controversial segment of the antenna is not the subject of this paper, and it could be a subject for some future detailed morphological review.

Figures

FIGURES 1 – 4. 1 — Corimalia strejceki, paratype, male, habitus, 2 — Corimalia aliena, male, habitus, 3 — Corimalia strejceki, female, habitus, 4 — Corimalia aliena, female, habitus.

FIGURES 5 – 12. Corimalia strejceki, paratype, male genitalia (5 – 8). 5 — penis, lateral view, 6 — penis, dorsal view, 7 — tegmen, 8 — apex of penis; Corimalia aliena, male genitalia (9 – 12). 9 — penis, lateral view, 10 — penis, dorsal view, 11 — tegmen, 12 — apex of penis.

FIGURES 13 – 14. 13 — Corimalia strejceki, paratype, mucro and comb of setae on apex of metatibia in male; 14 — Corimalia aliena, mucro and comb of setae on apex of metatibia in male.