Four new species of Lesticus (Carabidae, Pterostichinae) from China and supplementary comments on the genus

Abstract The genus Lesticus in China was studied, with descriptions of four new species: L.auripennissp. n. (Guangdong: Nanling, 24.93°N, 112.09°E); L.biisp. n. (Xizang: Mêdog, 29.32°N, 95.34°E); L.xiaodongisp. n. (Yunnan: Yingjiang, 24.71°N, 97.58°E); and L.violaceoussp. n. (Yunnan: Yingjiang, 24.71°N, 97.58°E). One new synonym is proposed: L.dubius Dubault, Lassalle & Roux, is a junior synonym of L.solidus Roux & Shi. An improved key and a catalogue accommodating all known Chinese Lesticus species are provided. Species relationships and the evolution of endophallic and other characters are preliminarily discussed.


Introduction
Lesticus Dejean belongs to the subtribe Trigonostomina (Carabidae: Pterostichinae) which includes six genera having an Oriental-Australasian distribution. This subtribe can be easily recognized by the very short and wide mentum tooth. Lesticus can be distinguished from other genera in the subtribe by the following character combination: first 1 Metepisternum short and wide, length less than or subequal to its basal width ( Fig. 9)  Diagnosis. Pronotum completely black; elytra metallic green or purple; pronotal lateral margins slightly sinuate before posterior angles; pronotal basal fovea almost glabrous, with restricted and very fine punctures only; metepisternum short and wide, length subequal to its basal width, with coarse punctures.
Comparisons. The new species is the only one among all Chinese Lesticus species with black pronotum and distinctly metallic elytra. Lesticus auripennis sp. n. is most similar to L. perniger and L. wrasei sharing the short, wide metepisternum with coarse punctures; pronotal lateral margins slightly sinuate before posterior angles; pronotal basal fovea shallowly incised; elytral intervals normal. The new species is distinguishable from the latter two species by elytra metallic color, restricted and very fine pronotal basal foveal punctures and a different shape of male genitalia. Median lobe of aedeagus of the new species is very similar to that of L. wrasei, but different in: (1) ventral margin slightly expanded near middle (versus completely straight); (2) apex a little less truncated; (3) in dorsal view, left margin slightly sinuate near middle (versus evenly curved).
Description. Body length 19.5-23.8 mm, elytra's greatest width 7.2-8.7 mm, both sexes with similar body forms. Head, pronotum, and appendage black and shining; maxillae, labial and maxillary palpomeres, lateral sides of labrum and terminal tarsomeres reddish brown; apical half of terminal palpomere yellow; elytra with strong metallic lustre, usually purple, in some individuals green; ventral side black. Head and pronotum with isodiametric microsculpture and minute punctures; elytra with isodiametric microsculpture.
Head glabrous, without coarse punctures; short and deep frontal depressions extended posterad to middle of eyes, with five to seven shallow longitudinal wrinkles behind frontal depression; anterior margin of labrum slightly emarginate; temporae slightly tumid behind eyes; antennal apex reaching elytra basal tenth.
Pronotum wider than head, PW/HW = 1.49-1.54, a little transverse, PW/PL = 1.24-1.38; pronotum widest near middle. Lateral margins not crenulate, curved in middle, slightly sinuate before posterior angles; posterior angles obtuse, apex rounded, not pointed outwards; posterior margin a little greater than anterior margin, extended slightly backward on each side. Median line shallow but distinct, not reaching posterior margin; disc almost glabrous, with a few shallow transverse wrinkles along median line at most. Basal fovea shallow but well defined; inner groove longer, approximately one-third length of pronotum; outer groove shorter, approximately one-fifth length of pronotum; basal foveal area with very fine punctures and wrinkles along inner and outer grooves, glabrous between inner and outer grooves.
Elytra oviform, EL/EW = 1.39-1.69, gradually widened to apex, widest at posterior third approximately; basal ridge complete, gradually curved, forming a distinct obtuse angle with elytral lateral margin, humeral teeth not pointed. Intervals barely convex; striae deeply incised, with very fine and sparse punctures alongside; scutellar stria short, apex free; parascutellar pore present; third interval with three setigerous pores: first one adjacent to third stria, the other two generally close to second stria (in a male paratype, third pore close to third stria); umbilicular series on ninth interval composed of 20-22 pores evenly spaced. Hind wings very small.
Ventral side: propleuron glabrous, without puncture or wrinkle; mesopleuron with a few coarse punctures on anterior half; metepisternum short and wide, length subequal to its basal width, with sparse and coarse punctures, usually 10-20, sometimes fewer; abdominal sterna glabrous on median portion, with few coarse punctures on lateral sides of sternum II and sometimes also sternum III, and very fine wrinkles on lateral sides of all sterna.
Legs: basal three metatarsomeres with distinct carina along almost full length of outer surface, fourth metatarsomeres with weaker carina only near base; fifth tarsomeres with 3-4 pairs of spines ventrally.
Male genitalia: median lobe of aedeagus with apical orifice opened dorsally; in lateral view, ventral margin slightly expanded in middle, apical portion straight, turned neither ventrally nor dorsally, basal portion slightly narrowed; in dorsal view, apical lamella very short, length approximately one-fourth basal width, apex rounded, slightly truncated; apical portion straight, oriented to neither left nor right. Endophallus ( Fig. 4) short, extending to dorsal-left, major portion of endophallus on left-dorsal side of aedeagus when everted; gonopore (gp, gonopore lobe folded in Fig. 4) located at a little before apical lamella, oriented to aedeagal apex. Basal tubercle (bt) typical of genus; basal band (bb) elongated, extended from apical orifice to base of lb. Six distinct lobes recognized: dorsal lobe (dl) very large and rounded, on right-dorsal surface; one additional basal lobe (bl) present on basal-ventral surface, close to dl, large and rounded, placed near apical lamella, decorated with very fine and sparse scales; right basal lobe (rb) a little smaller than dl, close to bl, apex sharply pointed, apex with dense and fine scales; right apical lobe (ra) on ventral side of gp, small, decorated with fine scales; left basal lobe (lb) a little larger than dl, on dorsal-apical surface, apex with dense scales; left apical lobe (la) small, close to lb, apex sharply pointing out, decorated with fine scales.
Distribution. This species is known only in Nanling, Guangdong (Map 1). The three localities of the type series are very close together. Etymology. The name "auripennis" is from Latin, "aur-" meaning colored and "pennis" meaning wing, referring to the elytra. This species is named for its distinctly metallic elytra.
Affinities. Lesticus auripennis sp. n. is close to L. perniger, L. ater, L. wrasei, and L. fukiensis among Chinese Lesticus fauna, sharing their short, wide metepisterna and similar shapes of the pronotum. Outside China, there are two other species with these characters: L. ornatus Dubault, Lassalle & Roux (Chiang Mai, Thailand) and L. restrictus Dubault, Lassalle & Roux (Shan State, Myanmar). These seven species could be recognized as one species group, which can be distinguished from other species of Lesticus by: (1) short, wide metepisternum, length less than or subequal to its basal width; (2) elytra third interval with two or three setigerous pores; (3) pronotum completely black, with no trace of metallic; (4) pronotum subquadrate or a little cordifrom; (5) relatively small body size, generally less than 24 mm. Diagnosis. Odd intervals prominently raised but not carinate, much wider than depressed even ones; third interval without setigerous pore; pronotal lateral margins crenulate through full length; basal fovea very deep; metepisternum short and wide, length subequal to its basal width; apical lamella of aedeagus truncated, shorter than basal width, without hook.

Lesticus bii
Comparisons. This new species can be readily distinguished from all the other Chinese species of the genus by the prominently raised odd elytral intervals. There are three other species (L. tricostatus Chaudoir, L. wittmeri Morvan, and L. cupricollis Pouillaude) from the Himalayan region with similar elytral characters, but they are different from the new species by: pronotal lateral margins not crenulated; odd intervals carinate, of about the same width as the even ones; apical lamella hooked or much longer than its basal width. Among these three, the new species is most similar to L. wittmeri from Bhutan for they both have pronotal basal fovea markedly prolonged anteriorly, elytral first interval not carinate, and apical lamella unhooked.
Head with dense and fine punctures on vertex and occiput; vertex densely rugose, deeper and longitudinal near eyes, shallower and reticular at middle; labrum with anterior margin nearly straight; temporae slightly tumid behind eyes; antennal apex reaching elytra basal sixth.
Pronotum wider than head, PW/HW = 1.38-1.44; width a little greater than median length, PW/PL = 1.13-1.21; pronotum widest near anterior third; lateral margins crenulate along full length, curved near middle, distinctly sinuate before posterior angles; posterior angles rectangular, not pointed outwards; posterior margin a little narrower than anterior margin, barely extended backward on each side, middle portion gradually concave; median line fine but a little deep, not reaching posterior margin; disc with dense transverse wrinkles alongside median line; basal fovea strongly incised, inner and outer grooves indistinct, completely fused together forming large and deep depression, extending forward beyond midpoint of pronotum, and gradually fused to widened lateral channel; basal fovea finely and densely punctated and rugose, wrinkles present on middle region of pronotal base between basal fovea.
Elytra oviform, EL/EW = 1.52-1.66, gradually widened to apex, widest near posterior third; basal ridge complete, forming indistinct obtuse angle with lateral margin, humeral teeth not pointed. Intervals with shallow transverse wrinkles; odd intervals strongly raised but not carinate, much more convex and wider, about twice width of the even ones; third interval without setigerous pore; striae deeply incised, with fine and sparse punctures alongside; scutellar stria very short, apex free; parascutellar pore on base of second interval, sometimes one additional parascutellar pore present; umbilicular series on ninth interval composed of 15-20 pores almost evenly arranged. Hind wings very small.
Ventral side: propleuron and mesopleuron with dense, fine punctures; metepisternum short and wide, length a little less than its basal width (Fig. 7), with dense, fine punctures; abdominal sterna glabrous medially, finely rugose laterally, lateral sides of sternum II and sometimes sternum III as well, finely and sparsely punctate.
Legs: basal three meso-and metatarsomeres prominently carinate along full length of outer surface, fourth tarsomeres barely carinate only near base; fifth tarsomeres with 3-4 pairs of spines ventrally.
Male genitalia: median lobe of aedeagus with apical orifice opened dorsally; in lateral view, ventral margin distinctly expanded in middle, apical portion straight, turned neither ventrally nor dorsally, basal portion a little narrowed; in dorsal view, apical lamella short, length about half basal width, apex truncated; apical portion straight, oriented to neither left nor right. Endophallus (Fig. 8) short and straight, extending to dorsum, the inscribed angle between axes of aedeagus and endophallus about 90°; main portion of endophallus on dorsal side of aedeagus when everted; gonopore (gp, gonopore lobe folded in Fig. 8) located at a little before apical lamella, oriented to dorsal side of aedeagus. Basal tubercle (bt) much larger than in other species, very densely and heavily spined; basal band (bb) absent. Five distinct lobes recognized: dorsal lobe (dl) small, nearly rounded, almost touching bt; right basal lobe (rb) divided into two separate lobes; right basal lobe I (rb-1) elongated, bent to dorsal direction of endophallus, placed at right-dorsal surface, decorated with dense and fine scales; right basal lobe II (rb-2) close to rl-1, bent to apical direction of endophallus, apex pointing out to dorsal direction, without scales; right apical lobe (ra) small, on right side of gp, bent to dorsal direction of endophallus, apex curved; left basal lobe (lb) absent; left apical lobe (la) close to dl, on left side of gp, bent to apical direction of endophallus, apex a little bifid.
Distribution. This species is known only in a few localities of Xizang, Mêdog (Map 2). Etymology. The new species is named for our friend Mr. BI Wenxuan, an excellent beetle collector, who was first to collect this rare and peculiar new species.
Affinities. Lesticus bii sp. n. was presumed to be close to L. tricostatus, L. wittmeri, and L. cupricollis for the following similarities: elytral odd intervals prominently raised; third interval without setigerous pore; pronotal lateral margins distinctly sinuate before posterior angles; and all from the Himalayan region. Among them, the new species has more plesiomorphies than the others, such as: all odd elytral intervals not carinate, apical lamella unhooked. Moreover, L. bii sp. n. was considered to be associated with two other Himalayan species (L. harmandi Tschitschérine, and L. holzschuhi Straneo) for their similarities in: pronotal lateral margins crenulate and distinctly sinuate before posterior angles; large, deep basal fovea; elytral third interval without setigerous pore; short metepisternum. Another species from Northern Myanmar, L. nigroviolaceus Dubault, Lassalle & Roux was similar to the new species in external and male genitalia characters, although pronotal lateral margins are not crenulate and odd intervals not raised.. Thus, all seven species are assumed to be associated with and forming one species group defined by: (1) short metepisternum, length less than or subequal to its basal width; (2) elytra third interval without setigerous pore; (3) pronotal lateral margins distinctly sinuate before posterior angles, large, deep basal fovea; (4) relatively small body size, generally less than 24 mm. Diagnosis. Pronotum metallic bluish violet, elytra completely violet; pronotum lateral margins slightly sinuate before posterior angles; pronotal basal fovea deep and glabrous, with very faint wrinkles; long, narrow metepisternum, length much greater than its basal width (L/W = 1.78), distinctly punctated; median lobe of aedeagus not expanded ventrally, apex markedly deflexed to right, very short apical lamella, apex a little truncated.

Lesticus violaceous
Comparisons. Among all Lesticus species from China, this new species is the only one with similar distinctly metallic color on the pronotum and elytra. From the slightly sinuate pronotal lateral margins and glabrous basal fovea, the new species is somewhat similar to L. tristis and L. chalcothorax. Besides their different color and body size, the two other species also differ from the new species in: median lobe of aedeagus distinctly expanded ventrally, apex of apical lamella more rounded.
The new species is also similar to L. desgodinsi from N. India and L. episcopalis from N. Myanmar in having a violet color on the elytra and pronotum as well as the pronotal lateral margins being somewhat sinuate before the posterior angles. Compared with the latter two species, L. violaceous sp. n. has less sinuate pronotal lateral margins; pronotal basal fovea less punctate; and ventral margin of aedeagus straight, not expanded near middle.
Description. Body length 25.1 mm, elytra's greatest width 9.2 mm. Head black, pronotum and elytra violet, with strong metallic lustre, pronotum somewhat blue in basal fovea and lateral channel; appendages black; tarsomeres, apical antennomeres, palpomeres and lateral sides of labrum reddish brown; ventral side black, with slightly metallic violet lustre. Head and pronotum with isodiametric microsculpture and minute punctures; elytra with isodiametric microsculpture.
Head glabrous, without coarse puncture and wrinkle; frontal impressions deep, with a few fine punctures inside; anterior margin of labrum slightly emarginate; temporae not tumid behind eyes; antennal apex reaching elytra basal tenth.
Pronotum much wider than head, PW/HW = 1.54, slightly transverse, PW/PL = 1.31, widest near middle. Lateral margins not crenulate; evenly curved at anterior two-thirds, slightly sinuate before posterior angles; posterior angles obtusely angulate, not pointed outwards; posterior margin a little narrower than anterior margin, extended slightly backward on each side. Median line deep, not reaching posterior margin; disc glabrous, without wrinkles. Basal fovea deep and narrow, inner groove nearly straight, about same length as outer one which is strongly curved, region between them deeply depressed; basal foveal area nearly glabrous, with a few very fine punctures and shallow wrinkles.
Elytra oviform, EL/EW = 1.65, gradually widened to apex, widest near posterior third; basal ridge complete, forming an indistinct obtuse angle with elytral lateral margin, humeral teeth not pointed. Intervals barely convex; striae deeply incised, with fine, sparse punctures alongside; scutellar stria long, apex free; parascutellar pore present on base of first stria; third interval with three setigerous pores: first one close to third stria, the other two close to second; umbilicular series on ninth interval composed of approximately 25 pores, sparse in middle and dense in anterior and posterior areas. Hind wings well developed.
Ventral side: propleuron with sparse, coarse punctures, a little denser on mesopleuron; long, narrow metepisternum, length much greater than its basal width (L/W = 1.78), with sparse, coarse punctures; abdominal sterna glabrous, almost impunctate, with only very shallow wrinkles on lateral sides.
Legs: basal two meso-and metatarsomeres with distinct carina only near base; fifth tarsomeres with 3-4 pairs of spines ventrally.
Male genitalia: median lobe of aedeagus with apical orifice opened dorsally; in lateral view, ventral margin straight, not expanded in middle, apical portion slightly turned dorsally before apical lamella, basal portion slightly narrowed; in dorsal view, aedeagus narrow, apical lamella very short, length approximately one-third of basal width, apex a bit truncated, apical fourth distinctly oriented to left side. Endophallus (Fig. 13) extending to dorsal-left, major portion of endophallus on left-dorsal side of aedeagus when everted; gonopore (gp) located at well before apical lamella, oriented to aedeagal base; gonopore lobe (gpl) long, a little spiral. Basal tubercle (bt) and basal band (bb) typical of the genus. Six distinct lobes recognized: dorsal lobe (dl) very large and compressed, on dorsal-right surface, pointing to base of aedeagus; one additional basal lobe (bl) present on basal-ventral side of dl, small and rounded, apex decorated with fine scales; right basal lobe (rb) large and wide, extended to ventral side of endophallus, surface with longitudinal impression; right apical lobe (ra) smaller than rb, rounded, at right-apical side of rb, at right surface of endophallus and close to gp; left basal lobe (lb) a little larger than rb, rounded, at ventral-apical side of rb, at ventral surface of endophallus; left apical lobe (la) small and compressed, close to left side gp, apex a little dilated and bifid.
Distribution. This species is known only by the holotype which was collected from Yunnan, Yingjiang, Nabang (Map 3).
Etymology. The scientific name "violaceous" comes from Latin, referring to the violet coloration of this new species.
Affinities. Among all Chinese Lesticus with the endophallus known, only L. rotundatus has similar male endophallic characters to the new species: endophallus strongly deflexed to left-dorsal side of aedeagus; gonopore pointed to the aedeagal base. Thus, a close relationship of these two species is possible, although they have quite different external and aedeagal characters. Diagnosis. Dorsal side bicolor: head and pronotum metallic bluish green, elytra dark metallic blue; pronotum lateral margins strongly sinuate before posterior angles; pronotal basal fovea deep, with fine punctures and wrinkles; posterior angles a little pointed; metepisternum long and narrow, length greater than its basal width (L/W = 1.35); median lobe of aedeagus slightly expanded ventrally, apical lamella very short, slightly thickened.
Comparisons. The new species can be readily distinguished from all the other known species from China by pronotal lateral margins strongly sinuate near base. From the coloration, shape of pronotum and median lobe of aedeagus slightly expanded ventrally, this new species is most similar to L. waterhousei Chaudoir from N.E. India and L. peguensis Bates from S. Myanmar. L. waterhousei differs in: much larger size (33-36 mm), pronotal basal fovea coarsely rugose, and apical lamella of aedeagus much longer. Lesticus peguensis differs in: pronotal posterior angles not pointed at all; apical lamella a little longer and not thickened.
Head: vertex nearly glabrous, with very fine shallow wrinkles; frontal impressions deep; coarse longitudinal wrinkles along inner margins of eyes; anterior margin of labrum distinctly emarginate; temporae not tumid behind eyes; antennal apex reaching elytra basal sixth.
Pronotum much wider than head, PW/HW = 1.52, slightly transverse, PW/PL = 1.32; widest near middle. Lateral margins not crenulate, evenly curved in middle, strongly sinuate before posterior angles; posterior angles nearly rectangular, pointed a little outward; posterior margin a little narrower than anterior, extended backward on each side. median line is deep, not reaching posterior margin; disc with very shallow transverse wrinkles alongside median line. Basal fovea deep, inner groove straight, a little longer than curved outer groove, region between them deeply depressed; basal foveal area with some fine but distinct punctures and wrinkles. Elytra oviform, EL/EW = 1.65, gradually widened to apex, widest near posterior third; basal ridge complete, forming an indistinct obtuse angle with elytral lateral margin, humeral teeth not pointed. Intervals barely convex, striae deeply incised, with fine and dense punctures alongside; scutellar stria moderately long, apex conjoined to first stria; parascutellar pore located at base of first stria; third interval with three setigerous pores: first one close to third stria, other two close to second; umbilicular series on ninth interval composed of approximately 25 pores, sparse in middle and dense in anterior and posterior areas. Hind wings well developed.
Ventral side: propleuron and mesopleuron with dense, coarse punctures; metepisternum long and narrow, length greater than its basal width (L/W = 1.35), with sparse, coarse punctures; abdominal sterna glabrous in middle, with dense, coarse punctures on lateral sides of sternum II and sternum III, and shallow wrinkles on lateral sides of all sterna.
Legs: three basal metatarsomeres with distinct carina along almost the full length of outer surface, three basal mesotarsomeres, and fourth with weaker carina only near base; fifth tarsomeres with 3-4 pairs of spines ventrally.
Male genitalia: median lobe of aedeagus with apical orifice opened dorsally; in lateral view, ventral margin slightly expanded in middle, basal portion not narrowed, apical lamella slightly thickened and turned ventrally; in dorsal view, aedeagus gradually narrows from middle to apex, apical lamella very short, length approximately onethird of basal width, apex a little truncated; apical portion a little inclined to right side. Endophallus (Fig. 17) straight, extending to apex, the included angle between axes of aedeagus and endophallus about 20°; major portion of endophallus located beyond apical lamella, inclined a little to left; gonopore (gp) located at well beyond apical lamella, oriented to aedeagal apex; gonopore lobe (gpl) long, a little spiral. Basal tubercle (bt) typical of the genus; basal band (bb) short, obsolete at apex, not reaching left surface of dl. Five distinct lobes recognized: large dorsal lobe (dl), divided into three sub-lobes by longish grooves: basal one longitudinal; middle one on right side of basal one, very narrow and transverse; apical one transverse, larger than the other two, without scales; single right basal lobe (rb), large and rounded, on right-apical side of dl, decorated with dense scales; right apical lobe (ra) smaller than rb, rounded, close to gp; left basal lobe (lb) very large and flat, near apex of bb; left apical lobe (la) very small, nearly imperceptible.
Distribution. This species is known only by the holotype, which was collected from Yunnan, Yingjiang, Nabang, the same locality as the previous new species (Map 4).
Etymology. The new species is named for our friend Mr. Yang Xiaodong, who collected the holotype of this beautiful and rare new species.
Affinities. Among all Chinese Lesticus we studied, L. tristis and L. solidus have the most similar male endophallic characters to the new species: endophallus straight, major portion extending to apical direction of aedeagus; in lateral view, the angle between axes of endophallus and aedeagus less than 30°. Moreover, these three species all have pronotal basal fovea not well punctated, and metepisterna much longer than its basal width. This suggests a close relationship among the three species. Notes on synonym. Lesticus solidus Roux & Shi was described based on a single female from Maoershan (Guangxi, China). Two years later, L. dubius Dubault, Lassalle & Roux was described from exactly the same locality based on four specimens including both sexes. In the present study, we compared the female holotype of L. solidus (Fig. 19) and a male (Fig. 20) and found that they are perfectly in accordance with the type locality and male genitalia illustrations ) of L. dubius. They are different only in: L. solidus with very faint violet lustre on elytra, and elytra more widened to apex. These differences also correspond with the original description of L. dubius. Among all our examined materials, the females generally exhibited elytra more widened to apex. Thus we considered it as a sexual dimorphic character. About the very faint violet lustre of L. solidus, it is more likely an individual variation rather than a specific character. This case is similar to head and pronotum color variations of L. dubius which were noted by Dubault et al. (2013). So, we herein synonymize L. dubius with L. solidus.
Supplementary descriptions on endophallus (Fig. 22): Endophallus straight, extending to apex, the angle formed by the axes of aedeagus and endophallus about 5°; major portion of endophallus located beyond apical lamella; gonopore (gp) located at a level well beyond apical lamella, pointing to aedeagal apex; gonopore lobe (gpl) long, a little spiral. Basal tubercle (bt) and basal band (bb) typical of the genus. Six distinct lobes recognized: dorsal lobe (dl) very large and rounded, on dorsal surface and sharply pointed out; right basal lobe (rb) divided into two separate lobes; right basal lobe I (rb-1) large and a little compressed, close to apical lamella, surface without scales; right basal lobe II (rb-2) a little larger than rb-1, rounded, at apical side of rb-1, decorated with sparse, fine scales; right apical lobe (ra) a little smaller than rb-1, rounded, between rb-2 and gp; left basal lobe (lb) large and compressed, close to apex of bb; left apical lobe (la) small and compressed, pointing out sharply, at left side of gp.

Discussion
Lesticus is an Oriental genus with more than a hundred described species , and several of them have impressive metallic color. Although this genus was well defined, different species in the genus usually have similar external and male genital characters, making species determination generally difficult. Moreover, due to the limited number of available characters for systematic study, solving species relationships in Lesticus was never attempted before. In Pterostichini, the endophallic characters were of value for species relationships (Shi and Liang 2015). Thus, in an attempt to resolve part of the species relationships in Lesticus, we studied the endophallus of all available Chinese species (14 of 18 known species). Based on the comparative morphology study, preliminary conclusions on endophallic character evolution and phylogenetic considerations within Lesticus are presented below.

Endophallus categories in Lesticus
According to the materials and endophallus illustrations provided by  that we examined, the endophallus shape is highly variable in Lesticus, but there are some regularities revealed. We classified here the endophallus of species studied (14 Chinese species and 19 species from other faunas) into four types, mainly based on the orientation of the gonopore and rotation or deflection of the endophallic axis.

Type I
The endophallus type I (as shown in Figs 8, 17, 22, 25 and 27) is the most common type among all examined species, and all other types can be explained as modifications based on this type. The enodphallus type I has the following character states: Endophallic axis nearly straight; extending to genital apex, or more or less deflected to dorsum, with the angle inscribed between axes of aedeagus and endophallus (AE-angle, axis of endophallus was the line between midpoint of apical orifice and gonopore) between 5° and 80°; gonopore oriented to endophallic apex; major portion of endophallus located at apical, apical-dorsal or dorsal side of aedeagus. Seven groups of features recognized: (1) basal tubercle (bt) at the base of endophallus, generally very small, its surface with very dense scales, bt rarely disappearing; (2) basal band (bb), a long and narrow chitinized band, beginning at right margin of apical orifice, then surrounding base of dl, and ending at left surface of it, bb sometimes shortened or obsolete; (3) dorsal lobe (dl) on dorsal basal surface of endophallus, close to dorsal margin of aedeagus, generally large and rounded, usually the largest lobe on endophallus and decorated with very coarse scales, sometimes divided into sub-lobes or separate lobes; (4) right basal lobe (rb) on right basal surface of endophallus, usually divided into two separate lobes; (5) right apical lobe (ra) on right surface of endophallus, close to gonopore, generally much smaller than rb; (6) left basal lobe (lb) on right basal surface of endophallus, sometimes divided into two separate lobes or almost imperceptible; (7) left apical lobe (la) on left surface of endophallus, close to gonopore, generally much smaller than lb. All lobes generally decorated with scales at least on apex.
A  (Figs 17, 23): endophallus almost straight, only slightly or not deflexed to dorsum, AE-angle 5° to 55°; gonopore at apical direction of aedeagus; dl very large, placed on dorsal surface; dl and rb sometimes divided; without additional basal lobe. Five Chinese species have the chalcothorax-form: L. solidus, L. tristis, L. xiaodongi, L. chalcothorax, and L. sauteri; (2) the auricollis-form (Fig. 27): endophallus markedly deflexed to dorsum, AE-angle 70° to 80°; gonopore at dorsal direction of aedeagus; dl placed on dorsal-right surface; dl, rb and lb all divided into two separate lobes; bb short and wide; one additional basal lobe (bl) present at right basal side of dl. Three Chinese species have the auricollis-form: L. deuvei, L. taiwanicus and L. auricollis. The remaining two species, L. perniger (Fig. 25) and L. bii (Fig. 8), are special within type I due to: bt less pointed than other species; lb completely absent; rb located well before midpoint of endophallus. But some other specialized differences might contradict their affinities: bt flat but very large and coarsely spined in L. bii; bb absent in L. bii, very long, reaching midpoint of endophallus in L. perniger; la with a heavily chitinized piece in L. perniger; rb divided into two separate lobes in L. bii.
Based on the endophallus illustrations provided by , 11 species of the Chinese fauna also have an endophallus of type I. Four of them have the auricollis-form endophallus: L. andamanensis (Chaudoir), L. mouhoti (Chaudoir), L. nubilus Tschitschérine and L. waterhousei (Chaudoir); and another four have the chalcothorax-form: L. buqueti (Castelnau), L. indus (Tschitschérine), L. kangeanensis Dubault et al. and L. stefanschoedli Kirschenhofer. The remaining three species cannot be categorized as either form: L. tricostatus Chaudoir, L. cupricollis Pouillaude and L. desgodinsi Tschitschérine. However, the former two species are clearly similar to L. bii sp. n. for both external and endophallic similarities. Besides Lesticus, some species of Trigonotoma (such as T. lewisi in Fig. 24) also have the endophallus straight and the gonopore placed well beyond the aedeagus apex (similar to the chalcothorax-form), but in Trigonotoma the endophallus generally has fewer or no lobes.

Type II
The endophallus type II (Figs 4,13) with three Chinese species representatives (L. auripennis sp. n., L. violaceous sp. n. and L. rotundatus Roux & Shi) is characterized by: endophallic axis markedly deflexed to left, gonopore oriented to left-basal side of aedeagus; dl placed on right side of endophallus; one additional basal lobe (bl) present on basal-ventral side of dl. Among these three, L. auripennis is different from the other two species by: bl located on right surface, almost reaching midpoint of endophallus; gonopore oriented to left-apical side of aedeagus. Another species, L. assamicus (Kuntzen) from north India, is also known to have the type II endophallus.
Type II endophalli are well characterized by the endophallic axis markedly deflexed to left, but it seems that such a character cannot support close relationships among species with the type II endophallus. Based on other similarities among related species, we inferred that the type II endophallus might be derived from type I by the elongation of the endophallic base and deflection of the endophallic axis to the left, with L. violaceous and L. rotundatus derived from the auricollis-form, and L. auripennis probably from a L. perniger-like form.

Type III
The endophallus type III (Fig. 26) is a peculiar type only found in L. magnus (Motschulsky) which has a wide distribution in East Asia. It is characterized by: endophallic axis short and markedly deflexed to aedeagal base; a large conical basal lobe (bl) forming conspicuous ventral projection; main portion of endophallus located on dorsal side of aedeagus; gonopore oriented to ventral side. Although peculiar, type III was assumed to have transformed from the auricollis-form of type I by: endophallic apex more deflexed to basal-ventral side; all primary lobes reduced in size and restricted at dorsal margin of endophallus; the presence of a very large additional basal lobe (bl).

Type IV
The endophallus type IV (Fig. 28) is characterized by the endophallic axis markedly helical on the basal portion. No Chinese species has a type IV endophallus; all known species (nine) of this type are from the Malay Archipelago (Philippines, Borneo, Java). The highly specialized helix-formed endophallus and its regional distribution may suggest close relationships among species of the type IV endophallus.
Although highly specialized, the type IV endophallus was still inferred as a modified type from the type I, and homologies of all lobes can be distinguished (Fig. 28). From the chalcothorax-form of type I, type IV is assumed to be transformed by: dl moved to apex and deflexed to left side; endophallic base before dl elongated and rotated; rb-1 enlarged and protuberant; rb-2 generally small; lb obsolete; la, ra, bb, and bt similar to those in type I; main portion of endophallus located on dorsal side of aedeagus; gonopore generally oriented to basal-dorsal side.

Chinese Lesticus species with unknown endophallus
There are four Chinese Lesticus species with the endophallus unknown. Based on external and aedeagal characters, we briefly discuss here their presumed relationships and predicted endophallic types.
Lesticus fukiensis Jedlička and L. wrasei Dubault, Lassalle & Roux: These two species are very similar in habitus and aedeagus features and have adjacent distributions. Compared to other species from China, they are most similar to and presumed to be closely related to L. auripennis sp. n., sharing the short and wide metepisternum; aedeagus only slightly or not expanded ventrally; in dorsal view, apical portion of aedeagus very slightly oblique to right side (might be associated with left deflection of endophallus). Thus, these two species are hypothesized to have endophallus character states similar to the type II of L. auripennis.
Lesticus ater Roux & Shi: Based on the short, wide metepisternum, this species was considered as belonging to the same group of L. perniger (see discussion under L. auripennis). But from the almost impunctate ventral surface and the peculiar shape of aedeagal apex, L. ater is an outlier in this group and its close allies are unclear. Nevertheless, from the symmetrical aedeagal apex (in dorsal view not oblique to right or left side), L. ater is hypothesized to have type I endophallus similar to L. perniger.
Lesticus praestans (Chaudoir): This species is assumed to be close to L. deuvei based on their similarities in several external characters, for example: metepisternum longer than its basal width; pronotal with metallic color; basal fovea distinctly punctate. Thus, an auricollis-form endophallus is hypothesized.

Evolution of other characters
It is difficult to infer species relationships in Lesticus from external characters only, because only very few characters are available, and many of them have lot of variation in the genus. Similar problems were also encountered when distinguishing similar species and determining identification keys. Nevertheless, there are still some character transformations that are widely presented in Lesticus and important in species determination. Some of the transforming polarities seem to be clear, while others are more complex. We selected here some of the most common transformed characters in Lesticus, inferred their transforming polarity and preliminary evaluated their taxonomic value.
Coloration: The metallic or black pronotum is a constant character in most species and seems to have some systematic importance. The non-metallic color could be apomorphies. The head coloration always conforms with that of the pronotum, but elytra coloration should be regarded as an independent character, although in many groups it seems to have some linkage with pronotal coloration.
Punctures: The punctures of pronotal basal fovea, elytra intervals, propleuron and metepisternum are useful to distinguish similar species, but they are variable in some species. Generally, punctures on different body parts are somewhat linked, but it seems that these punctate characters have very little importance when inferring species relationships.
Pronotum shape: The pronotum shape is variable and important in identification of Lesticus species. Different shapes of pronotum are recognizable, among which the subquadrate shape (as in L. magnus) is inferred to be plesiomorphic, while round (as in L. andamanensis) and cordiform (as in L. janthinus) are apomorphies. Some species relationships might be inferred by specialized pronotal shape. For instance, the strongly cordiform pronotum may suggest a close relationship of L. janthinus with its allies from Indonesia.
Pronotal margin: About 13 species with quite different external appearance have crenulate pronotal lateral margins. This apomorphic character state is useful in species identification and relationship inference, but it might have homoplastic transformations also.
Elytral discal pores: Most species of the genus have three setigerous pores on elytral third interval, but some of them have only one or two pores, and a very few species have none. It is clear that three pores is plesiomorphic, and the reduced number of discal pores might support some monophyletic groups.
Elytral interval: Seven species of Lesticus have elytra modified by odd intervals raised, ridged or widened. This apomorphic state occurs in two groups having rather distant distributions (Himalayan Mountains and Lesser Sunda Islands) and some other characters are also different (i.e. elytral discal pores). Thus, these two groups might not be close and homoplastic transformations are inferred.
Metepisternum: The length of metepisternum has important value for species identification and the definition of some species groups. It seems that this character has distinct binary states: the shortened form (associated with reduced hind wings) with its length shorter or subequal to its basal width, and the normally longer form (associated with developed hind wings) with a length more than 1.3 times its basal width. Similar to most genera of Carabidae, the shortened metepisternum is apomorphic, and associated with the reduction of hind wings and adaptation to mountain habitat. But there seem to be several parallelisms in its character transformations.
However, this subgeneric system was not accepted in many important revisions (i.e. , and many species described later without original subgenera assignment were subsequently placed in subgenera very casually by cataloguers. For instance, two very close species, L. auricollis and L. deuvei, were assigned to different subgenera (Löbl and Löbl 2017). Moreover, many species presently assigned to Lesticus s. str. do not have the typical cordiform pronotum of the subgenera, and some of them even have elongated metepisternum making the definition of subgenera unclear.
In the present study, we examined all Chinese Lesticus species and compared them to many foreign species according to some important morphology characters. We found that in Lesticus the short metepisternum is not always in accordance with cordiform or round pronotum, and neither pronotum shape nor metepisternum length can support a monophyletic group inferred by the endophallic characters (see above). Both of the type species of Lesticus and Triplogenius have similar type IV endophalli which supports these two species being actually closely related. All the above evidence, object of the present infra-general taxonomy, originated with .
In conclusion, except the monotypic Celistus, the other two subgenera in the present concept are obviously not monophyletic, but an improved infra-general system cannot be proposed at this time. Thus, we suggest that it is better not to introduce subgenera in the genus Lesticus before a comprehensive phylogenetic study is completed. Mr. Shengping Yu (Beijing) for their help in collecting important specimens for the study. This work was partially supported by the National Key R&D Program of China (2016YFC1202102) and the National Natural Science Foundation of China (grant Nos 31401992 and 31572235).