Epexochus lehmanni (Ménétries), Menetries

Meregalli, Massimo & Talamelli, Fabio, 2009, Revision of the genus Epexochus Reitter, with description of three new species (Coleoptera: Curculionidae: Lixinae: Cleonini), Zootaxa 2011, pp. 47-68 : 50-57

Epexochus lehmanni (Ménétries)

Cleonus Lehmanni Ménétries, 1849: 251 .

Leucochromus Lehmanni (Ménétries) : Chevrolat 1873: 2 [as Lhemanni], 99; Faust 1904: 191.

Epilectus Lehmanni (Ménétries) : Faust 1904: 208.

Epexochus lehmanni (Ménétries) : Reitter 1913: 40; Ter-Minasyan 1968: 516; 1988: 46. Cleonus (Epexochus) Lehmanni (Ménétries) : Csiki 1934: 39.

Exochus latus Chevrolat, 1873: 3 ; 99 (syn. n.).

Epilectus Lehmanni ? latus (Chevrolat) : Faust 1904: 208.

Cleonus (Epexochus) Lehmanni ? latus (Chevrolat) : Csiki 1934: 39. Leucochromus Lehmanni var. consobrinus Faust, 1904: 191 , 192. Epilectus Lehmanni var. consobrinus ( Faust) : Faust 1904: 208. Cleonus (Epexochus) Lehmanni ab. consobrinus (Faust) : Csiki 1934: 39. Leucochromus consobrinus (Faust) : Ter-Minasyan 1972: 543; 1988: 43. Epexochus consobrinus (Faust) : Arzanov 2005: 150.

Redescription. Dimensions: Body length excluding rostrum: 18.10 mm. Rostrum: length 3.89 mm, width 1.99 mm (ratio 1.95). Pronotum: length 5.10 mm, width 5.90 mm (ratio 0.86). Elytra: length 13.06 mm, width 8.19 mm (ratio 1.59). Ratio of elytral to pronotal length 2.56 (holotype).

Habitus. Body oval, broad, moderately convex ( Figs. 1 , 10). Integument dark ferruginous to blackish, densely covered on dorsum with small, simple, acuminate scales and on underside with bifid to multifid scales.

Rostrum straight, more than twice as long as wide, dorso-lateral margins rounded, not keeled, nearly straight from base to apex; epistoma prominent anteriorly, apex straight; dorsum with narrow glossy median keel extending to apex before epistoma, flanked by a broad triangular convex plate, whose sides are broadened anteriad, extending from base, where sides of convexity closely approach median keel, to antennal insertion, where sides nearly reach dorso-lateral margins; dorsal convexity delimiting narrow, relatively shallow dorsal furrows; upper margin of scrobes glossy, evenly curved, sinuate posteriorly, directed towards, and interrupted before, lower margin of eye; lower margin of scrobes parallel to upper margin, reaching underside near base, interrupted on underside at lateral margins of rostrum; underside with keels linearly converging, strongly so towards base and there confluent; surface weakly concave between keels; in lateral view rostrum straight, of equal thickness from base to apex, dorso-lateral margins slightly sinuate basally, median convexity distinctly higher than sides, median keel very weakly curved, sinuate basally, angle between forehead and rostrum strongly obtuse. Surface of rostrum glossy, minutely punctulate and with sparse, moderately larger, isolated punctures, more distinct basally and on sides before eyes. Vestiture consisting of dense, white, glossy, acuminate, simple scales, directed towards middle near base and progressively forward towards apex, progressively more elongate towards apical part, often with two minute and acute lateral basal projections, which towards sides are longer and transform part of the scales into a digitate form with three teeth; sides in front of eyes with sparse, brown trifid scales not hiding integument; pregenae and underside with elliptical, acuminate, glossy white scales; setae sparse, relatively thick, on dorsum short, appressed to integument and limited to basal part, on pregenae and underside longer and thinner, semi-erect, clearly distinct; epistoma punctulate, with microscopic golden setae (Figs. 12–13, 16).

Antenna slender. Scape narrow, very weakly thickened at apex, slightly curved anteriad. Funicle with segment 1 subquadrate, 2 cylindrical, as wide as and 1.5 times as long as 1; 3–6 similar to each other, transverse; 7 subquadrate, slightly larger and twice as long as 6, fused to club. Club elliptical, as long as funicle segments 4–7 together, club segment 3 as long as previous two segments together, annulus clearly distinct; scape with sparse, ovate or digitate scales and narrow setae, funicle with dense white scales, club with very dense, golden, hair-like scales, lacking setae (Fig. 17).

Head broad, nearly as long as wide, not sharply differentiated from base of rostrum, interocular distance wider than rostrum at base, forehead nearly flat, with small interocular pit and narrow median glossy line extending to vertex; this moderately convex in middle. Vestiture consisting of dense, white scales and short, barely distinct, orange setae reclined on integument, inserted in small, spaced punctures. Eyes flat, large, moderately narrowed below, lower margin broadly rounded.

FIGURES 10–20. Epexochus lehmanni , structural details (10, 12–13, 16–18: holotype; 11, 14–15, 19–20: specimen from Borokhoro). 10, habitus, lateral view; 11, habitus, ventral view; 12–13, rostrum, dorsal and ventral views; 14–15, tarsus, ventral and dorsal views; 16, rostrum, lateral view; 17, antenna; 18, pronotum; 19–20, maxilla, dorsal and ventral views. Scale bars: 10–11: 10 mm; 12–15, 18: 2 mm; 16–17: 1 mm; 19–20: 500 μm.

Pronotum broad, nearly flat, base subrectilinear, moderately and evenly arched, posteriorly not medially protruding towards elytra, sides nearly parallel or feebly diverging towards apical quarter, then moderately, evenly curved to apex; anterior margin very weakly sinuate; surface smooth, minutely punctulate and with sparse, slightly larger, round punctures, often with a small, glossy, round bare patch near lateral margin; median line glossy, very narrow, barely distinct at the extremes, usually slightly more evident and broadened on disc; pronotum in lateral view faintly convex, maximum height near base. Vestiture consisting of oval, acutely pointed scales inserted in minute punctures, usually white-yellowish on dorso-lateral part and on sides, dark brown on disc forming an irregular pattern, narrowed anteriorly and widened posteriorly, with some whitish spots inside, and also brown on part of sides, mainly forming an anterior patch; scales on sides progressively more slender, setae orange or light brown, short and completely appressed against integument, inserted in larger sparse punctures (Fig. 18).

Scutellum very small, triangular, setose.

Elytra oval–elliptical, in lateral view moderately convex, maximum height behind middle of length, declivity oblique; base weakly arched, humeri not prominent, sides weakly curvilinear, with maximum width behind middle of length, evenly rounded at apex. Intervals wide, even ones narrower than odd ones, 3 and 5 clearly higher than others, particularly in basal half, 6 and 8 not reaching base, 7 and 9 fused basally into a broad, weakly convex hump, separated by a narrow furrow from base of interval 5. Striae very narrow and shallow, with barely distinct punctures. Vestiture consisting of very dense, oval, acutely pointed, whitish alternating with brown scales in very variable patterns; the latter frequent on dorsum in a more or less continuous layer, where white scales form irregularly scattered patches; intervals 7–11 usually with whitish scales and seldom with brown patches; interval 11 with digitate scales; setae golden coloured, semi-erect, shorter than an interval width, more distinct on declivity and sides ( Fig. 36 ).

Legs slender. Femora slightly thickened medially. Tibiae narrow, fore tibia weakly sinuate, middle and hind tibiae straight, apex not expanded; vestiture consisting of dense, whitish scales, often replaced with brown scales near apex of femora, and dense long, semi-erect, white setae inserted in distinct, small punctures. Tarsi with segments 1 and 2 of fore and middle tarsi triangular, 2 broader than 1, 3 lobed, lobes very shortly expanded; segment 1 of hind tarsus longer, nearly three times as long as wide, 2 slightly longer than wide, 3 very short; all segments with white scales and setae expanded side- and downwards (Fig. 15); onychium elongated, slightly thickened in apical half; underside lacking adhesive pad, replaced by downward-directed, thick, orange setae (Fig. 14); claws slender, divergent, connate at base ( Fig. 26 ).

Venter. Prosternum with low hump before fore coxae. Ventrite I relatively narrow, width between hind coxae and margin narrower than space between coxae; II slightly narrower than I; III and IV moderately narrower than II; V short, clearly impressed before apex; vestiture consisting of very dense coating of elongate, slender, bifid or multifid scales, white with a narrow brown basal patch, slightly expanded towards sides, on ventrites II–IV; ventrite V with a broader brown triangular patch, narrowed apically and nearly reaching apex; setae whitish, long, very narrow and relatively dense, inserted in barely visible, small punctures (Fig. 11).

Genitalia. Aedeagus slender, tubular, curved, lamella shortly sub-triangular, apex subacute or narrowly rounded ( Figs. 27–35 ). Sternite VIII of Ψ with narrow arms, connate at base, lamina sclerotised only at apex of arms ( Fig. 21 ). Spermatheca with ramus usually sub-basal ( Figs. 22, 25 ). Hemisternites as typical of genus ( Fig. 23 ).

Material examined. Type series. Cleonus lehmanni Ménétries, holotype Ψ: KAZAKHSTAN, AKTOBE PROV.: "Emba-Steppe [approximately 48°N 57°E], … [illegible], 1840 / Cleonus lehmanni m. / Ménétries det. [pr.] / Lehmanni Ménétr. / Cleonus lehmanni, Ménétries 1849 , Holotypus, 2008 Meregalli vid. (red). Leucochromus lehmanni var. consobrinus Faust , 3 syntypes: KAZAKHSTAN, ZHAMBYL PROV.: "Syr Daria, Aulie Ata" [= Taraz, 42°53'N 71°22'E] ( SMTD). Exochus latus Chevrolat , holotype Ψ (see Perrin & Meregalli, 2008): "Kirghis or." ( MNHN).

Non-type specimens. RUSSIA, VOLGOGRAD PROV.: "Elton ok., ozera na doroge [49°07'N 46°34'E], 4.VI. [19]52, Buriascheva", 1 ɗ ( ZIN). KAZAKHSTAN: " 200 km ot [from] Atbasara [Atbasar: 51°17'N 68°19'E], Akmol. obl., A. Emeljanov, 3.VI. [19]57", 1 ɗ ( ZIN). "Turg. obl., Myn-sai [approximately 49°N 65°E], 3.V. [19]14", 1 ɗ ( ZIN); "Betpak-Dala, Sary-Kamys [46°02'N 70°12'E], 7.V. [19]55, L. Serkova", 1 ɗ ( ZIN); " 40 km O st. Kzyl-Dzhar [48°18'N 69°38'E], Karagand. obl., L. Arnoldi, 23.V. [1]962", 1 ɗ ( ZIN); " 10 km S–V [N-E] g. Balkhasha, Z. Matis, 23.V.1966 ", 1 ɗ ( ZIN); "Syr Daria, Aulie Ata" [= Taraz, 42°53'N 71°22'E], 102 ex (100 exx SMTD, 2 ex MER); id, under C. lehmanni var. consobrinus Faust , 55 exx ( SMTD); "Turkest.: Aulie-ata, E. Wilberg", 2 Ψ (MER); "Aulie Ata", 2 exx (MER); "Semirechye [approximately 43–46°N 74–79°E], step k Balkhashy, Makhonin, 1909" 1 ɗ ( ZIN); "Okr. oz. Balkhasha, V.1907, Mamisson", 1 ɗ ( ZIN); "Koibun, Semirjetschensk, coll. Winkler, 3 ɗ 1 Ψ. (MER); "Balchasch, Matthiessen", 1 ɗ (POD); "Yu-V [S-E] Kazakhstan, Taldy - Kurgan. obl., pustynya Ak-Tau, V. N. Plasolov, 10.V.1994 ", 1 Ψ ( ZIN); "Okr. Kopala [45°08'N 79°01'E], 18.IV.1910, Lukjanovitsch", 1 ɗ ( ZIN); "Kazakhst. m.-or., Saryesik-Atyrau des., Enbek [45°15'N 75°29'E], 1.5.1990, Beneš + Voříšek leg.", 2 Ψ (1 Ψ MER, 1 Ψ VOR); " Kazakhstan SE, Bakanas vill. [44°48'N 76°16'E], 04/1993, leg. Saldaitiz" 1 Ψ ( CSNV); "S.E. Kazakhstan, Ili riv., Bakanas vill, 2.5.1996 ", 1 ɗ ( CSNV); " Kazakhstan, Ily desert, S fr. Bakanas, 2/ 4.V.1997, Klimenko A., 2 ɗ (1 ɗ MER, 1 ɗ CSNV); " Kazakhstan, Prov. Almaty, 5 km NE Burundisu, 550 m, 78°38'E 43°43'N, 17.V.1994, leg. Gy. Fábián & I. Retezár", 2 ɗ 2 Ψ (2 ɗ 1 Ψ POD, 1 Ψ MER); "Mzhd. Tshilikom i Tsharynom, 13.V. [18]89, Gr. Grzhimailo", 1 ɗ ( ZIN); " Kazakhstan, 1965, r. Tsharyn, ur. Sartogai [43°31'N 79°14'E], 3.VI.1964, Kostin Badenko", 1 ɗ 1 Ψ ( ZIN); "Dzharkentsk. utz., r. Ili [43°50'N 80°00'E], 1/ 2.V.1909 ", 1 Ψ ( ZIN); "Zailiskii Ala Tau, sklon Moyun-saz (?), 20.06.[19]23, Pashina" 1 ɗ ( ZIN). CHINA, XINJIANG: "Dzhungaria, Borokhoro Geb. [43°55'N 82°06'], Coll. Hauser, 6.05", 59 ex (18 exx: MER; 2 ex: POD; 4 ex: ZMHB; 35 NMW); "Kuldsha [= Yining, 43°53'N 81°16'], A. Regel", 1 ɗ ( ZIN); "Mzhd. Suidunom i Khorgossom, 28.V. [18]89, Gr. Grzhimailo", 1 Ψ ( ZIN); "Dzhinkho [= Jinghe, 44°36'N 82°53'], 13.VI. [18]89, Gr. Grzhimailo", 3 exx ( ZIN); "Dzhungar, Urumtschi"[43°55'N 87°34'], 1 Ψ (MER). UNDETERMINED COUNTRY: "Kirghiz, Eversm.", 1 ɗ 1 Ψ. ( SMTD);"R.m., Kirg. stepp." (red, pr.), 1 Ψ ( ZIN); no data, "93" 1 ɗ (MER).

Distribution ( Fig. 82 ). Epexochus lehmanni has a broad range, which stretches more than 3000 km between its extremes. The holotype is from the northernmost limit, but most of the known specimens were found in south-eastern Kazakhstan and in Chinese Kazakhstan, in present-day north-western Xinjiang, on the Dzhungar Alatau mountains.

Biology. Nothing is known about the host plants of the species, a single record existing of a specimen found "on Artemisia ". This plant is associated with steppe habitats, growing at altitudes from sea level in northern and central Kazakhstan to at least 1500 m on the Alatau ridge.

Remarks. The description of the E. lehmanni was based on a single specimen, found "in springtime in the steppe near the Emba [river]" ("D'apres un seul individu pris au primtemps dans les steppes près de l'Emba", Ménétries 1849: 252). This type specimen, housed in the ZIN, is thus the holotype.

Two more names are applicable to this species. Chevrolat (1873) described E. latus , based on a specimen ex Gebler's collection, but since this type specimen was not located again, the name has always been considered as of doubtful status. Faust (1904) included it with a question mark under Epilectus lehmanni , and since then it was never cited again in taxonomic works; in the Coleopterorum Catalogus Csiki (1934) simply followed Faust in doubtfully referring it to E. lehmanni . A part of Gebler's collection was recently rediscovered in the MNHN ( Perrin & Meregalli 2008); it includes the type of latus and its pertinence to Epexochus was confirmed. The type locality of latus was cited as " Deserto Kirghisorum ", but this unfortunately is a very vague indication since the Kirghiz desert embraces a very large area of central Asia, including most of central and southern Kazakhstan. Two specimens housed in the SMTD, extremely similar to the type of latus , are labelled, in Fausts' handwriting, "Kirghiz, Eversmann" and " lehmanni , cum typo comp.". They look somewhat intermediate between the central and southern Kazakhstan populations of E. lehmanni , being quite similar to the forms from Aulie-ata except for having shorter elytral setae. The status to be afforded to Epexochus latus is discussed below.

The second species name associated with E. lehmanni was proposed by Faust (1904: 192) as Leucochromus lehmanni var. consobrinus , for specimens from Aulie-ata [= Djambul, now Taraz, in southern Kazakhstan] characterised by the elytral vestiture consisting of predominantly greyish-white scales and occurring sympatrically with the typically brownish-coloured specimens. Later in the same work, Faust (1904: 208) referred lehmanni and its variety consobrinus to the new genus Epilectus Faust. According to Art. 45.6.4 of the ICZN (1999), lehmanni var. consobrinus Faust has infrasubspecific rank, since the content of Faust’s work reveals that he used the name for a sympatric colour variety, i.e. the consequence of intrapopulational variability defined as an infrasubspecific entity in the glossary of the ICZN. Faust's name was not again considered until Ter-Minasyan (1972) raised it to species level (as " Leucochromus consobrinus Faust , stat. nov. "), applying the name to a specimen from Mongolia. This generic attribution is surprising, because a) apart from its ambiguous original description, consobrinus had always been referred to Epexochus , which is clearly distinct from Leucochromus , b) the Mongolian entity belongs to Epexochus and not to Leucochromus , and c) it is also a species different from Faust's consobrinus from Aulie-ata. However, despite this misapplication to another taxon, according to Art. 45.6.4.1 Ter-Minasyan's adoption of Faust's name for a species makes consobrinus an available name at subspecific rank, with its original authorship. Ter-Minasyan equipped the Mongolian specimen with a red label reading " Leucochromus consobrinus Faust , holotypus ", but that is an erroneous designation since the type series is from Aulie-ata, as in Faust's collection. The species erroneously attributed by Ter-Minasyan to Leucochromus consobrinus Faust is described below as Epexochus mongolicus sp. n. Finally, Arzanov (2005), based on some differences between consobrinus and L. imperialis in the structure of the internal sac of the aedeagus, considered the former as a valid species in the genus Epexochus and formally established this combination.

The evaluation of the status to be given to consobrinus and latus (species, subspecies or synonym of E. lehmanni ) requires an analysis of the intra- and interpopulation variation of E. lehmanni . Only few specimens could be examined from central and northern Kazakhstan, where the type locality of lehmanni lies. These are characterised by the dorsum being mainly covered with dark brown scales, with the white scales forming a few roundish spots on the disc and the top of the declivity. The declivity itself and the lateral parts of the elytra are generally whitish. The elytral setae vary from whitish, short and sparse (holotype, Fig. 1 ; Elton lake, Fig. 2 ) to dense, golden, erect (particularly on the declivity), more than half as long as an interval width (Myn-Sai, Fig. 3 ; Atbasa, Kzyl-Dzhar). The rostrum is usually short, narrower at the base and has a prominent median keel, with the anterior triangular plate usually clearly distinct, the dorso-lateral margins low and in lateral view more concave in their basal part. The base of the pronotum is usually medially slightly lobed, and the elytra are widest behind the middle and broader towards the apex. The aedeagus of the specimen from Elton lake has a short, acute lamella and is strongly curved in lateral view ( Figs. 28–29, 32 ), but that of the specimens from Kzyl-Dzhar and Betpak-Dala has a better developed lamella and is less strongly curved ( Fig. 33 ). A specimen from the steppes north of the Balkhash lake and a few others generically labelled "Balkhash lake" have quite a similar pattern of elytral scales; these specimens are smaller and have shorter setae, although not as short as in the specimens from Yenbek and the medium to lower course of the Ili river, described below. Other specimens also generically labelled Balkhash, but from different collectors, have predominantly greyish scales ( Fig. 4 ), but the inaccuracy of their collection data precludes any further deliberations of the significance of this variation in colour pattern in the demes from the steppes around the Balkhash lake. The few specimens simply labelled "Kirgiz., Eversmann" and the holotype of latus ( Fig. 5 ) have a more varied pattern, with the round pale spots less evident, and the whitish scales scattered in irregular patches and small stripes. As in the specimen from Myn-Sai, the elytra are broadly rounded towards the apex, the median keel of the rostrum has the triangular plate more raised and distinct, the base of the pronotum is completely linear, not lobed towards the scutellum, the elytra are parallel-sided from the base to at least half their length and the sides have denser, more erect setae. These specimens are somewhat intermediate between those from northern Kazakhstan and those found at the end of the 19th century at the upper course of the Syr Darya, in the surroundings of Aulie-ata ( Fig. 6 ), the type locality of consobrinus Faust. A large number of specimens of this population could be examined. They have more globose elytra with rounded sides, very distinct hair-like, golden, semi-erect setae nearly as long as an interval width rather densely distributed over the entire body, and the colour pattern of the elytra consists of roughly equal areas of brown and white scales, with pale round patches absent but usually a sharp contrast between the dark and pale parts, with several alternate longitudinal stripes and spots. The rostrum is usually shorter, narrower at its base and has a prominent median keel; the anterior triangular anterior triangular plate is usually raised and the dorso-lateral margins are low, in lateral view slightly concave in their basal part. Several Epexochus specimens were found in the Semirechye region in south-eastern Kazakhstan, south of the Balkhash lake (Koibun, Yenbeck, Bakanas, etc.). These are characterised by very short, barely visible setae, the rostrum longer and broader at the base, appearing slightly conical and with the dorso-lateral margins slightly convergent towards the antennal insertions and better developed and relatively sharply raised, the median keel sharper, the triangular plate less evident and in lateral view the rostrum often hardly curved. The elytra have predominantly pale scales, with brown scales mainly placed along the striae and denser before the declivity to reach the intervals and form a vague, darker transversal patch. Their sides are broadened, sometimes not very evenly curved. The length of the setae is not constant in the specimens from this area: of the two males collected together along the Ili river, south of Bakanas, one has dense and relatively long, erect setae on the elytra and the legs and the other almost indistinct setae on the elytra and very short and sparse on the legs; this specimen also has predominantly dark scales, with white scales limited to a few broadly rounded patches, and its pronotum is not completely straight at the base. There are no other differences in phenotypic traits, including the shape of the aedeagus. More populations are recorded from along the middle and upper course of the river Ili, in southeastern Kazakhstan and north-western Xinjiang. The specimens from the steppe around the Tsharyn river, in south-eastern Kazakhstan ( Fig. 7 ), are rather similar to those from the Semirechye region and have very short setae. Many Epexochus specimens were collected by Hauser in May 1906 on the Borokhoro ridge, more to the east and at a higher altitude, along the upper course of the Kash river, a tributary of the Ili river, in present day Xinjiang. Most of these specimens are characterised by the whitish scales covering most of the elytra, with pale brownish scales confined to two broad transverse patches before the declivity, not sharply delimited, and to some small spots along the striae. The pronotum is usually dark, with white scales limited to the sides and along the median line ( Fig. 9 ). Two specimens have most of the elytral scales brownish ( Fig. 8 ), whereas six are nearly completely white, including on the pronotum and before the declivity. In contrast to the other demes, the scales in this population are barely glossy. The elytral setae on the Borokhoro specimens are generally whitish, moderately erect and distinctly shorter than an interval width; their density and length vary, but they are always clearly distinct in profile, longer than the setae of the forms from the steppe north and east of Almaty. The rostrum is slightly variable in length and curvature, and the median triangular longitudinal keel is usually well differentiated, only flatter in few specimens. The base of the pronotum is generally truncate, without any curvature towards the scutellum. The shape of the elytra and the size of the body are relatively uniform in all these specimens, the size ranging from 16.81 to 20.00 mm (mean of the specimens examined 18.35 mm) and the elytra have subparallel sides, with the maximum width approximately in the middle and from there evenly converging towards the apex. The specimen labelled Urumtschi [= Ürümqi, Xinjiang] is also referable to this form, as is that from Kuldja [= Yining, Xinjiang], at the base of the Borokhoro ridge. In the specimens of south-eastern Kazakhstan and Xinjiang the aedeagus always is weakly curved and has a slightly rounded lamella ( Figs. 27, 30–31, 34–35 ).

In conclusion, it seems that each population shows peculiar characters, usually associated with the form of the elytra, the colour pattern of the scales and the length of the setae. The specimens from the Kazakhstan steppe north and west of the Balkhash lake share the brown colour, usually with white scales in round spots, but vary in the length of the setae and in the shape of the rostrum; in southern Kazakhstan and north western Xinjiang the demes have the elytra mainly whitish with often relatively dense and erect setae and a sharply truncate pronotal base; in the Semirechye region most of the specimens have very short or nearly indistinct setae, the elytra with pale scales, the pronotal base often weakly curved and a longer rostrum. The shape of the aedeagus varies hardly at all, and the female genitalia are also not particularly differentiated among the various populations. It is hence impossible to recognise a clear and univocal differentiation of some demes, and the different morphological traits can only be regarded as variations at population level, not indicative of distinct taxa at species rank. Latus Chevrolat, 1873 is therefore treated as a junior synonym of lehmanni Ménétries, 1849 , and consobrinus Faust, 1904 , which is itself referable to latus , is thus likewise a junior synonym of lehmanni .

Figures

FIGURE 82. Distribution of the genus Epexochus [map taken from Encarta World Atlas 2000 (Microsoft Corporation), elaborated with Photoshop 7.0 (Adobe Systems Incorporated)].

FIGURES 1 – 9. Epexochus lehmanni, habitus. 1, holotype; 2, specimen from Elton lake; 3, specimen from Myn-sai; 4, specimen from Balkhash lake; 5, Exochus latus, holotype; 6, specimen from Aulie-ata; 7, specimen from Burundisu; 8 – 9, specimen from Borokhoro. Scale bars: 10 mm.

FIGURES 21 – 39. Epexochus, genitalia, claws and scales. Female genitalia (21 – 23: specimen from Kzyl-Dzhar; 24 – 25: specimen from Aulie-ata). 21, 24, sternum VIII; 22, 25, spermatheca; 23, hemisternites. Claws. 26, specimen from Borokhoro. Aedeagus, dorsal and lateral views and detail of apex. 27, 30, 35, specimen from Koibun; 28 – 29, 32, specimen from Elton lake; 31, specimen from Dzharkentsk; 33, specimen from Betpak; 34, specimen from Borokhoro. Elytral scales. 36, holotype of E. lehmanni; 37, holotype of E. korotyaevi; 38, holotype of E. voriseki; 39, paratype of E. mongolicus. Scale bars: 21, 23 – 24, 27 – 31: 1 mm; 26, 32 – 35: 500 μm; 36 – 39: 100 μm.