Chydaeus dissimilis, Kataev, Boris M., Wrase, David W. & Schmidt, Joachim, 2014

Kataev, Boris M., Wrase, David W. & Schmidt, Joachim, 2014, New species of the genus Chydaeus from China, Nepal, Myanmar, and Thailand, with remarks on species previously described (Coleoptera: Carabidae: Harpalini), Zootaxa 3765 (1), pp. 1-28 : 3-6

Chydaeus dissimilis sp. n.

( Figs 1 , 7–12 )

Type material. Holotype: ♂, " THAILAND: Chieng [= Chiang] Mai Province Doi Inthanon summit , 2500 m 6.X.1981 Zool. Museum Copenhagen leg." ( ZMUC).

Paratypes: 4 ♂, 8 ♀, same data as holotype ( cJS, cWR, ZIN, ZMUC).

Description. Dorsal habitus: Fig. 1 .

Size. Body length 9.6–11.0 mm, width 4.4–5.0. mm; in holotype 9.6 and 4.4 mm, respectively.

Color. Black, shiny on dorsum; base of mandibles, outer margins of labrum often paler; palpi, antennae and legs blackish brown; apices of palpomeres and antennomeres, tarsi, occasionally also tibiae brown or reddish brown.

Microsculpture. In both sexes distinct throughout on dorsum; consisting of more or less isodiametric meshes on head and pronotum and of narrow transverse meshes on elytra; meshes in central portion of pronotum and in male also on head under and behind eyes slightly transverse; meshes in male slightly finer than in female.

Head. Rather large (HWmax/PWmax = 0.70–0.73 and HWmin/PWmax = 0.61–0.65), impunctate. Eyes moderately convex (HWmax/HWmin = 0.12–0.18). Tempora oblique, sloped to neck. Clypeus very shallowly emarginate, almost straight, vaguely bordered apically. Frontal foveae short and shallow, without distinct clypeoocular prolongations. Clypeo-frontal suture slightly deepened. Supraorbital pore located at level of hind margin of each eye, removed on frons at a distance of about three to four diameters of pore from supraorbital furrows. Labrum deeply emarginate apically. Left mandible truncate at apex. Ligular sclerite narrow, almost not widened anteriorly, subtruncate at apex. Antennae slightly surpassing pronotal basal edge, with antennomeres 5 to 7 each about 1.8–2.0 times as long as wide.

Pronotum. Distinctly transverse (PWmax/PL = 1.51–1.64), widest at the beginning of the second third, markedly narrowed basad (PWmax/PWmin = 1.28–1.36). Sides largely rounded, occasionally almost straight in posterior third, each with one lateral setigerous pore in widest point of pronotum. Apical margin markedly emarginate, bordered only laterally. Basal margin nearly straight medially, slightly oblique laterally, distinctly bordered throughout, almost as long as apical margin and noticeably longer than elytral base between humeral angles. Apical angles slightly less than 90° (lateral aspect), protruded anteriad, blunt or very narrowly rounded at apices. Basal angles very obtuse, each with a very small, obtuse denticle at apex. Pronotal disc moderately convex, markedly sloped to apical angles. Lateral depressions beginning from apical angles, somewhat narrow anteriorly (approximately as wide as width of antennomere 2 basally), rather evenly widened posteriad and reaching basal margin. Basal foveae narrow, slightly deepened, usually isolated from lateral depressions by convexities; area between basal foveae convex. Pronotal surface finely and irregularly punctate in lateral depressions and in and around basal foveae.

Elytra: Moderately convex, oval, rounded at sides [EL/EW = 1.34–1.40, EL/PL = 2.70–2.86 (2.70–2.79 in male and 2.71–2.86 in female), EW/PWmax = 1.26–1.31 (1.26–1.30 in male and 1.28–1.31 in female)], widest slightly behind middle. Humeri subangulate, each with a tiny acute denticle, recognizable only from behind. Sutural angles in both sexes acute, with blunt apices slightly isolated from each other. Basal borders nearly straight medially, slightly sinuate laterally, joined each with lateral margin at very obtuse angle. Striae impunctate, slightly crenulate, impressed along entire length. Intervals impunctate, very slightly convex. Umbilicate setal series continuous, not interrupted at middle.

Hind wings reduced to very small stubs.

Ventral surface. Prosternum covered with short setae; prosternal process not projected posteriad. Proepisterna (propleura) impunctate. Metepisterna approximately as long as wide or slightly longer than wide, markedly narrowed posteriad ( Fig. 7 ). Sternum VII (last visible) in both sexes somewhat truncate at apex and with two pairs of setae along apical margin.

Legs. Metacoxae each with an additional posteromedial setigerous pore and without any additional, neither setigerous or unsetigerous, foveae medially. Tarsi glabrous dorsally, but in male usually with few setae on dorsal surface of widened pro- and mesotarsomeres; tarsomere 5 with usually three, occasionally four pairs of lateroventral setae. Metatarsi slightly shorter than HWmin, with tarsomere 1 markedly longer than tarsomere 2, but shorter than tarsomeres 2+3. In male, protarsi markedly enlarged, about as wide as protibia at apex (tarsomere 2 slightly wider than long, tarsomere 3 markedly wider than long) and tarsomeres 1–4 with adhesive vestiture ventrally); mesotarsomere 1 not enlarged, longer than wide; mesotarsomere 2 about as long as wide, slightly wider than mesotibia at apex; mesotarsomere 3 markedly wider than long, slightly narrower than mesotibia at apex; mesotarsomere 4 distinctly smaller than tarsomeres 2 and 3, and deeply concave apically; and mesotarsomeres 2 and 3 with adhesive vestiture ventrally.

Female genitalia ( Figs 8–9 ). Apical stylomere rather strongly arcuate.

Aedeagus. Median lobe in lateral aspect ( Fig. 10 ) bent just behind basal bulb, almost straight along ventral side and sharply bent dorsad just at apex forming a transverse dorsoapical flange; in dorsal aspect ( Fig. 12 ) median lobe almost straight. Terminal lamella ( Fig. 11 ) wide and short, with sides almost rectilinearly converging posteriad; apex of dorsoapical flange acute. Apical orifice in dorsal position, prolonged to basal bulb. Internal sac with a large spiny formation at middle and with very small, in fact only suggested, narrow spiny patch basally on right side.

Etymology. The specific name is an adjective meaning “unlike, different”.

Comparative remarks. Chydaeus dissimilis sp. n. is a third species of the bedeli group. The new species easily differs from the two other species of this group, C. bedeli (Tschitschérine) and C. similis Kataev & Schmidt , in having the following distinctive characters: pronotum with more obtuse basal angles and with finer punctation restricted to the lateral depressions and to the area in and around basal foveae; dorsal surface of head and pronotum in both sexes with distinct microsculpture; metepisterna much shorter, about as long as wide; hind wings reduced; terminal lamella of aedeagal median lobe wider. For comparison, C. bedeli and C. similis have these characters as follows: pronotal basal angles almost rectangular or slightly obtuse; punctures on pronotum coarser and also present at least at apical margin; frons (in both sexes) and disc of pronotum (in male) lacking microsculpture; metepisterna noticeably longer than wide; hind wings fully developed; and terminal lamella of aedeagus in male narrower. In shape of median lobe of aedeagus with almost straight ventral margin, C. dissimilis sp. n. is rather similar to C. bedeli , however, the internal sac of the new species is quite different and characterized by an extremely short longitudinal spiny patch which is reduced to a very small strip on right side basally. Differences in structure of median lobe between the new species and C. similis are more distinct: the latter species has the ventral side of aedeagal median lobe convexly rounded and the apex directed dorsad, and the internal sac lacks any traces of a right longitudinal spiny patch. Additionally, the aedeagal terminal lamella of C. similis is much narrower than that of C. dissimilis sp. n. and of C. bedeli .

According to Kataev & Schmidt (2002), C. similis and C. bedeli as well as the subspecies of the latter species ( C. bedeli vietnamensis Kataev & Schmidt , C. b. difficilis Kataev & Schmidt , C. b. interjectus Kataev & Schmidt , and C. b. longipennis Kataev & Schmidt) are mainly recognizable on the basis of genital characters of males. Further investigations showed that females of some of these taxa may be recognized by features of their elytral microsculpture (in contrast to this, elytral microsculpture of males is almost invariable among the mentioned taxa and in all cases consists of very fine transverse meshes making the surface appearing polished). In females of Chydaeus bedeli difficilis , C. b. interjectus and C. b. longipennis, the elytral microsculpture consists of slightly transverse to almost isodiametric meshes which on intervals 2 to 9 are strongly engraved, making the surface appearing fairly mat, and meshes on interval 1 are finer engraved, making the surface appearing more shiny. In females of C. b. vietnamensis , elytral microsculpture is more or less uniform throughout, finer than that in subspecies difficilis, interjectus and longipennis on intervals 2 to 9 and consisting of distinctly transverse meshes; surface of elytra is slightly shiny, but less shiny than in males. In females of the nominative subspecies of C. bedeli and in females of C. similis , elytral microsculpture is more or less uniform, very fine, consisting of narrow transverse meshes; surface of elytra is shiny, similar to that of males. Females of C. dissimilis sp. n. agree in this character with females of the nominative subspecies of C. bedeli and females of C. similis .

Distribution. Known only from the Doi Inthanon Mountain in northern Thailand (Chiang Mai Province). This locality is geographically separated from the distributional areas of both the other species of the bedeli group: C. bedeli is widely distributed over the Himalaya, the eastern Tibetan Plateau and North Vietnam. C. similis occurs in South-West China. The record of C. bedeli from Doi Inthanon, Thailand by Ito (2003) is based apparently on specimens of C. dissimilis sp. n.

Figures

FIGURES 1 – 6. Chydaeus, dorsal habitus (holotypes). 1, C. dissimilis sp. n.; 2, C. shaanxiensis sp. n.; 3, C. kabaki sp. n.; 4, C. weishanensis sp. n.; 5, C. belousovi sp. n.; 6, C. putaoensis sp. n. Scales = 2.0 mm.

FIGURES 7 – 12. Chydaeus dissimilis sp. n. (7, 10 – 12, holotype; 8 – 9, paratype). 7, left metepisternum; 8, laterotergite IX and stylus; 9, stylus; 10, 12, median lobe of aedeagus; 11, terminal lamella of median lobe. 7 – 8, ventral aspect; 9 – 10, lateral aspect; 11 – 12, dorsal aspect. Scales: A = 0.5 mm (Fig. 11), B = 1.0 mm (Figs 7 – 10, 12).