Junnanotrechus Uéno & Yin, 1993

Belousov, Igor A. & Kabak, Ilya I., 2014, A taxonomic review of the genus Junnanotrechus Uéno & Yin, 1993 (Coleoptera: Carabidae: Trechinae), with description of six new species, Zootaxa 3811 (4), pp. 401-437 : 403-406

Genus Junnanotrechus Uéno & Yin, 1993

Junnanotrechus Uéno & Yin, 1993: 355 , type species: Junnanotrechus microps Uéno & Yin, 1993 . Junnanotrechus Deuve, 2011: 67 .

The genus was thoroughly described by Sh.-I. Uéno and W.- Y. Yin (1993) but the new discovered species demonstrate a significant deviation in some character states from the previously known taxa, what makes it necessary to re-describe the genus.

Description. Habitus oblong, convex, with narrow fore-body and elongate elytra. Appendages robust and rather long. Dorsum glabrous in some species, very briefly and sparsely pubescent in others.

Head large. Eyes small, normally markedly shorter than tempora, moderately to strongly protruding. Supraorbital carina either free or connected to upper posterior edge of eye. Tempora long and convex, always with sparse and long setae. Frons convex, especially in median part. Parietal transverse impression well-defined. Two supraorbital setigerous pores on each side of head, very seldom one more smaller seta between these. Two pairs of clypeal setae of which exterior ones are much longer. Labrum broadly concave, sexsetose. Mandibles ( Fig. 1 ) slender (especially gracile in species with hypertrophied head, such as J. elegantulus sp. n.), rather straight, curved mostly in apical third; tooth on right mandible ( Fig. 1 b) with premolar distinctly isolated from retinacle and far removed from the distal denticle of the latter, median denticle obtuse, weakly protruding, approached to the premolar, inner cutting edge between median and distal denticles broadly concave. Labial tooth well-defined, its distal part often obliquely truncate from ventral side and, therefore, seems to be directed a bit dorsad, always with clear longitudinal ventral groove, from nearly parallel-sided to triangular-shaped, broadly rounded, slightly truncate or even bifid apically, bordered basally. Mentum free (mental suture distinct even in reflected light) in J. microps and allied northern species while submentum completely fused with mentum, without any trace of transverse mental suture between them in J. elegantulus sp. n. ( Fig. 2 ), J. oblongus sp. n., and J. triporus sp. n. In J. koroleviellus sp. n., sublateral parts of mental suture perceptible. Median part of mentum and adjacent part of submentum strongly convex. Normally six (more seldom 4–7) submental setae, of which lateral (not subangular) being longest and median ones shortest ( Fig. 2 ). Median group rather instable, occasionally one or seldom two setae of this group lacking (as it was indicated in the original description by Sh.-I. Uéno and W.-Y. Yin) or, on the contrary, one more seta present. Subangular setae only weakly longer than median ones, but their pores usually more distinct. Both maxillary and labial palpi rather slender. Maxillary palpi ( Fig. 3 ) nearly glabrous, only with a few very short hairs in subapical portion of penultimate segment and on its anterior surface as well as in subapical part of the second segment. Penultimate segment of labial palpi ( Fig. 4 ) quadrisetose. Glossum triangularly produced antero-ventrad, bearing a couple of long median setae and 2–3 shorter lateral setae on each side; paraglossae slender, gradually arcuate, clearly protruding beyond level of glossum apex.

Pronotum rather narrow, strongly constricted towards base, its shape strongly varying according to the species; basal portion more or less lobed due to deep lateral emarginations of basal margin (only in J. koroleviellus sp. n., basal margin of pronotum nearly simple, with lateral parts strongly obliquely truncate). Anterior margin of pronotum convex in all species, front angles being markedly removed posteriad and strongly rounded. In J. elegantulus sp. n., hind angles of pronotum strongly shifted anteriad, pronotal base obliquely truncate laterally. Lateral border continuous in most species, reduced posteriorly in J. elegantulus sp. n. Both anterior and posterior lateral setae of pronotum well-developed.

Elytra oblong oval, without distinct humeri, evenly convex, with maximum width near their mid-length. Elytral striae more or less strongly reduced. Only in two species, J. schuelkei sp. n. and J. triporus sp. n., the first stria continuous and well-impressed, striae 2–4 either completely reduced or barely traceable in anterior half of elytra, other striae partially traceable or completely effaced. In other species, even the first elytral stria indistinct. Examination of elytra in translucent light ( Fig. 5 ) allows a more exact localization of both the discal setigerous pores and elytral striae since the latter becoming perceptible due to longitudinal rows of punctures on the undersurface of elytra (elytral pillars). Interspace 1 narrow compared to very wide interspaces 2 and 3, stria 3 clearly sinuate inward at level between second and third discal setigerous pores. Two anterior discal setigerous pores attached to stria 3, preapical pore in apical cross of striae 2 and 3, usually a little closer to the latter, while the third discal setigerous pore more or less strongly, depending on the species, displaced laterad and located either in stria 4 or on interspace 4, often in anastomosis of striae 3 and 4, very seldom in stria 3 (such position observed occasionally only in J. oblongus sp. n.) or on interspace 5. Preapical pore present in most species, missing in J. triporus sp. n. Two apical pores and complete set of pores in umbilicate series which is divided into three groups typical for most trechines: humeral one, consisting of 4 approximately equidistant pores, median and preapical groups, each consisting of two pores.

Prosternal processus not margined. Metepisterna slightly longer than wide, glabrous, their surface smooth.

Tibiae rather straight, from relatively slender to thick, more or less distinctly grooved externally; their anterior surface either with very sparse and rather long pubescence ( J. elegantulus sp. n.) or glabrous, at most, with vestigial hairs in distal third (most species of the genus). J. oblongus sp. n. is intermediate in this respect, with some specimens characterized by a few brief hairs located mostly near apex of front tibiae. In general, the pubescence of the anterior surface of front tibiae correlates well with the development of the whole pubescence of the dorsum. Male protarsi ( Fig. 6 ) with two basal segments strongly dilated, inwardly dentate, and provided with adhesive appendages beneath.

Visible abdominal sternites 2 and 3 partly fused, suture between them distinct laterally and occasionally medially. Visible abdominal sternites 4 – 6 with two median setae; anal sternite of male with two, that of female with four setae along its posterior margin. Surface of sternites with distinct micropunctures provided with tiny hairs becoming more dense and regular posteriorly, especially so on anal segment.

Microsculpture of body surface more or less reduced, normally more distinguishable on pronotum, partially on head and occasionally on elytra. Surface polish and shining, often iridescent.

Male genitalia ( Figs. 9 , 12 , 15–16 , 19–20 , 23–26 , 29–30 , 33 ) rather uniform in all hitherto known members of the genus: median lobe medium- to large-sized, apex more or less curved upward, basal bulb unusually long, widely open ventrally; parameres subrectangularly curved near mid-length, both proximal and distal portions nearly straight, the latter very gracile, with extremely narrow apex, each bearing 3–6 (usually 4) apical setae. Both parameres without distinct ventral apophyses. Endophallus armature consisting of folded scaly areas, without welldefined lamellae. Genital segment (urite) with proximal part completely fused.

Sexual dimorphism. Members of the genus reveal only the slight differences in the body shape between the two sexes: females, on average, possess wider elytra (the differences in both the EL/EW and EW/PW ratios are significant at p<0.001 level in four and three species and at p<0.05 and p<0.01 level in one more species, correspondingly, based on Mann –Whitney U test); head slightly bigger (differences in the PW/HW ratio sifnificant in two species) and have shorter elytra and legs (the differences in the EL/TiL and EL/AL ratios are significant in five and four species, respectively, including the p<0.001 level of significance in three species for each index). Additionally, in some species, there are significant differences between two sexes in the disposition of the umbilicate pores on the elytra: in females, the pores of the humeral group are located closer to the elytral base while the other umbilicate pores – closer to the elytral apex that may be easily explained by the more broadly ovate shape of the elytra in female specimens.

Comparative notes. In their original description, Sh.-I. Uéno and W.-Y. Yin put Junnanotrechus in the Agonotrechus series as being remotely related to Nesiotrechus S. Uéno, 1995 (= Lamprotrechus S. Uéno, 1975) (Uéno 1975; 1995), Taiwanotrechus S. Uéno, 1987 and Stevensius Jeannel, 1923 . According to these authors Junnanotrechus readily differs from all the above genera in having the preapical pore and one additional discal setigerous pore in apical half of elytra on interval 5, or in stria 4 (i.e. in location outward of stria 3, in “external series” sensu Sh.-I. Uéno and W.-Y. Yin), glabrous front tibiae with external groove and unique conformation of the male genitalia (Uéno & Yin 1993).

The newly described species of the genus demonstrate a clear variation in three of the five above listed characters: presence of the preapical pore (always missing in J. triporus sp. n.); position of the external discal setigerous pore which varies from stria 3 (occurring very seldom in J. oblongus sp. n.) to more typical for the genus position in stria 4 or seldom on interspace 5; and, finally, the pubescence of the anterior surface of front tibiae which is well-developed, at least, in J. elegantulus sp. n. Additionally, J. elegantulus is unique within the genus in having more or less reduced lateral border of pronotum in its posterior part, a character state which it shares with Taiwanotrechus . Obviously, the new taxa break to certain extent morphological boundaries of the genus, but the transformation (variation) patterns of the corresponding character states suggest direct relationships between congeners and a rather high degree of isolation of the genus Junnanotrechus from related genera. To summarize, the members of the genus Junnanotrechus are externally distinguished from the above mentioned related genera mainly by the presence of the third discal setigerous pore of elytra which tends to be translocated toward stria 4.

The distinctive characters of the male genitalia (except for the sagittal aileron which turned out to be welldeveloped in some new species) appeared to be rather uniform within the genus despite of strong differences in shape and size of the aedeagal median lobe. Indeed, all species of the genus possess the very long basal bulb of the median lobe which is widely open ventrally, the extended scaly areas without differentiated copulatory pieces in the endophallus, the characteristically shaped parameres, deprived of ventral apophyses, with very thin and straight apical portions bearing short apical setae. In addition to these characters indicated by Sh.-I. Uéno and W.-Y. Yin, it is worth noting that the male genital segment (urite) is completely fused in proximal portion in all Junnanotrechus as it is normally observed in members of the genera Trechodes Blackburn, 1901 and Perileptus Schaum, 1860 . This character, though rather unusual for most Trechini , shows certain variation within the subtribe Trechodina (for example, the urite is not similarly fused in Pachytrechodes Jeannel, 1960 , although this genus seems to be closely related to Trechodes ) and, therefore, its taxonomic importance should be admitted with some reservation.

Figures

FIGURE 9. Male genitalia of Junnanotrechus microps Uéno & Yin: a—lateral view, b—dorsal view, c—parameres, d—genital segment.

FIGURE 12. Male genitalia of Junnanotrechus wrasei sp. n.: a—lateral view, b—dorsal view, c—parameres, d, e—genital segment.

FIGURE 33. Male genitalia of Junnanotrechus elegantulus sp. n.: a—lateral view, b—dorsal view, c—genital segment.

FIGURES 1 – 6. Junnanotrechus elegantulus sp. n., paratype: 1 — mandibles: a—left, b—right; 2 — mentum, submentum, ligula and labial palpomeres; 3 — maxilla; 4 — labial palpus; 5 — elytra: a—left elytron, b—right elytron; 6 — male protarsus.

FIGURES 15 – 16. Male genitalia of Junnanotrechus baehri Deuve: a—lateral view, b—dorsal view.

FIGURES 19 – 20. Male genitalia of Junnanotrechus triporus sp. n.: a—lateral view, b—dorsal view, c—genital segment.

FIGURES 23 – 26. Male genitalia of Junnanotrechus koroleviellus sp. n.: a—lateral view, b—dorsal view, c—parameres, d—genital segment.

FIGURES 29 – 30. Male genitalia of Junnanotrechus oblongus sp. n.: a—lateral view, b—dorsal view, c—genital segment.