Kenyacus pusillus, Kataev, 2019

Kataev, Boris M., 2019, A review of the Afrotropical genus Kenyacus (Coleoptera: Carabidae: Harpalini) from the Rwenzori Mountains, with description of seven new species, Zootaxa 4679 (3), pp. 463-498 : 490-492

Kenyacus pusillus sp. n.

( Figs 54 , 74–81 , 82b )

Material examined. Holotype: ♂, “ UGANDA, Western Region, Kasese District, 13.5 km NWW Nyakalengija, Rwenzori Mts. National Park, env. of John Matte Hut , 0°23.038’N 29°55.801’E, accuracy 7 m, extent 15 m, h = 3427 m, Erica forest, sifting leaf litter [3555] [Garmin 60CSx; WGS84] V.I. Gusarov 11.viii.2008 U123” ( ZMUN).

Paratypes: 3 ♀♀, same data as holotype ( ZMUN, ZIN) ; 2 ♀♀, “ UGANDA, Western Region, Kasese District, 15 km NWW Nyakalengija, Rwenzori Mts. National Park, env. of John Matte Hut , 0°23.189’N 29°55.307’E, accuracy 11 m, extent 100 m, h = 3447 m, Erica forest, sifting leaf litter [3566] [Garmin 60CSx; WGS84] V.I. Gusarov 12.viii.2008 U133” ( ZMUN) ; 1 ♀, “ UGANDA, Western Region , Kasese District, 15– 13.5 km NWW Nyakalengija, Rwenzori Mts. National Park , env. of John Matte Hut, 0°22.950–.972’N 29°55.305–.772’E, accuracy 3 m, extent 15 m, h = 3399–3403 m, sifting leaf litter [3565] [Garmin 60CSx; WGS84] H. Elven 12.viii.2008 U132” ( ZMUN) ; 4 ♂♂, “ UGANDA, Western Region , Kasese District, 12 km NWW Nyakalengija, Rwenzori Mts. National Park , main trail from John Matte Hut to Nyabitaba Hut, 0°22.801’N 29°56.711’E, accuracy 6 m, extent 15 m, h = 3241 m, Erica , Hypericum , bushes and grass, sifting leaf litter [3594] [Garmin 60CSx; WGS84] V.I. Gusarov 17.viii.2008 U160” ( ZMUN, ZIN).

Description. (5 males and 6 females measured). Habitus as in Fig. 54 . Body length 3.2–3.6 mm, width 1.4–1.6 mm.

Colour: Body light brown to brown (most examined specimens teneral), dorsal surface slightly shiny, ventral surface slightly paler than dorsal surface; apices of mandibles infuscate; elytral suture paler than other elytral surface; palpi, antennae and legs brownish yellow; antennae slightly infuscate from antennomere 2 or 3.

Head: Comparatively large, in males HWmax/PWmax 0.72–0.77 (m = 0.76) and HWmin/PWmax 0.63–0.68 (m = 0.66); in females these indices respectively 0.72–0.78 (m = 0.76), and 0.63–0.68 (m = 0.66). Eyes with large facets, very slightly convex, HWmax/HWmin 1.13–1.17 (m = 1.15) in males and 1.13–1.19 (m = 1.15) in females, separated from buccal fissure at distance of slightly less than width of antennomere 1. Tempora short, at most about third as long as eye, flat or slightly convex. Frons and vertex convex. Fronto-clypeal suture distinct, impressed, as deep as frontal furrows. Supraorbital setigerous pore located just behind level of posterior margin of eye, removed from supraorbital furrow at a distance of length of antennomere 2. Labrum almost straight anteriorly. Clypeus with slightly prominent apical angles and more or less straight apical margin between them. Mentum and submentum fused, submentum with two setae on each side (lateral seta very short and occasionally absent). Mandibles mediumsized; left mandible evenly bent in apical portion, with acute apex. Dorsal microsculpture in both sexes present throughout, consisting of distinct isodiametric meshes on clypeus and of mixture of finer isodiametric and slightly transverse meshes on frons and vertex; meshes on frons more or less obliterate. Antennae surpassing basal edge of pronotum approximately by apical antennomere, with antennomeres 7–9 slightly longer than wide; in female antennae slightly shorter than in male, with shorter antennomeres.

Pronotum: Comparatively narrow, PWmax/PL 1.21–1.34 (m = 1.27), widest at the end of anterior third, moderately narrowed posteriorly, PWmax/PWmin 1.24–1.32 (m = 1.28); lateral seta inserted slightly before widest point. Sides rounded anteriorly, usually more or less straightly, more rarely very slightly sinuately, converging from widest point to basal angles. Apical margin very shallowly arcuately emarginate or almost straight; apical angles only slightly projecting ahead, acute, blunted or narrowly rounded at tip. Basal margin equal to or slightly narrower than apical margin and noticeably narrower than elytral base, almost straight medially and rounded laterally; both apical and basal margins not bordered. Basal angles obtuse, narrowly rounded at tip, not or only scarcely projecting posteriorly. Disc moderately convex, strongly sloped to apical angles and flattened latero-basally. Lateral furrows very narrow, slightly widened in basal half, reaching basal angles and prolonged on basal margin till basal foveae. Each basal fovea very shallow, oval, not clearly delimited, isolated anteriorly from lateral furrow by small convexity. Surface of pronotum impunctate, occasionally with fine wrinkles medially at apical and basal margins. Anterior transverse depression variable, usually wide, not distinctly delimited. Median line very thin, superficial, often indistinct at apical and basal margins of pronotum. Microsculpture present throughout, similar to that of K. similis sp. n. and K. angustatus sp. n. ( Fig. 17 ), consisting of large, slightly transverse meshes.

Elytra: Oval, widest at middle or just behind it, in males EL/EW 1.38–45 (m = 1.41), EL/PL 2.56–2.72 (m = 2.65), and EW/PWmax 1.40–1.51 (m = 1.47); in females these indices respectively 1.39–1.44 (m = 1.41), 2.48–2.78 (m = 2.63), and 1.40–1.50 (m = 1.46). Humeri prominent, widely rounded. Preapical sinuation very shallow, in most specimens sides in apical fifth rather sharply curved inside and then almost straightly converging to apex. Sutural angle in both sexes narrowly rounded at tip. Basal edge slightly sinuate or almost straight, widely arcuately curving inside humerus up to lateral margin. Lateral gutter narrow along entire length. Elytral disc convex in lateral and caudal views. Striae thin, faintly crenulate, slightly impressed along entire length, their bases somewhat indistinct. Parascutellar setigerous pore present, large. Parascutellar striole highly reduced, often absent. Intervals slightly convex throughout, almost not narrowed posteriorly; intervals 2 and 3 almost parallel-sided or slightly widened at apex; interval 3 without discal pore. Microsculpture distinct throughout, similar to that of K. similis sp. n. and K. angustatus sp. n. ( Fig. 21 ), consisting of slightly transverse meshes.

Ventral surface of thorax and abdomen: Prosternum with one or few moderately long erect setae medio-apically. Metepisternum slightly wider than long, narrowed posteriorly. Basal abdominal sternites glabrous, two last visible (VI and VII) sternites sparsely pubescent, VI much more sparsely than VII; apical margin of last visible sternite with two pairs of setae in both sexes, widely rounded or subtruncate at middle.

Legs: Metacoxae without any additional setae. Tarsi glabrous dorsally. Tarsomere 5 without setae ventrally. Meso- and metatarsomeres 1 about as long as or slightly shorter than meso- and metatarsomeres 2+3, respectively. Pro- and mesotarsomeres 2–4 of male slightly dilated (mesotarsi very faintly) and with biseriately arranged long adhesive scales ventrally; mesotarsomere 4 rather deeply emarginate.

Male genitalia: Median lobe ( Figs 74, 76 ) relatively larger than in the related species K. angustatus sp. n. and K. similis sp. n., stout, with large basal bulb (slightly destroyed in holotype); in dorsal view markedly narrowed in apical portion, in lateral view arcuate, more strongly bent at middle of median lobe, with slightly convex ventral margin in apical portion. Terminal lamella short, scarcely curved dorsally, without apical capitulum; in dorso-caudal view narrowly rounded at apex ( Fig. 75 ). Internal sac without any sclerotic elements.

Female genitalia: Very small ( Figs 77–81 ); laterotergite (hemisternite) relatively small and wide, almost symmetrical, membranous apically, without setae and spines. Basal stylomere elongate, usually with few shot setae apically. Apical stylomere slightly shorter than basal stylomere, with short thick seta at ventral edge of outer margin, in ventral view curved, with comparatively narrow base ( Figs 78, 81 ), in lateral view somewhat wide, parallel-sided or slightly narrowed apically, with rounded apex ( Figs 77, 79, 80 ).

Etymology. The specific name is a Latin adjective meaning “very little, tiny” and referring to the small body size of the new species.

Distribution ( Fig. 82b ). This new species is known from the Bujuku Valley at altitudes of 3241–3457 m in the south-eastern part of the Rwenzori Mountains, where it occurs sympatrically with K. gusarovi sp. n., K. parvus sp. n. and K. berndi sp. n.

Bionomics. According to the label data, specimens were collected by sifting leaf litter in Erica and Hypericum forest with bushes and grass in lower layers ( Fig. 92 ).

Comparison. This new species is very similar in size and habitus to the allopatric species K. angustatus sp. n., K. similis sp. n. and K. ruwenzoricus , but can be distinctly distinguished from them by elytra with striae clearly impressed along entire length and with slightly convex elytral intervals combined with pronotal basal angles obtuse, narrowly rounded at tip ( Fig. 54 ). Additionally, median lobe of aedeagus in K. pusillus sp. n. ( Figs 74, 76 ) is relatively slightly longer than that in K. angustatus sp. n. and K. similis sp. n. and with slightly convex ventral margin in apical portion in lateral view. Female genitalia of K. pusillus sp. n. with more or less parallel-sided apical stylomere ( Figs 77, 79, 80 ) are somewhat similar to that of K. similis sp. n. ( Figs 69, 71 ) and markedly different in this respect from the female genitalia of K. angustatus sp. n. ( Figs 62, 64 ) and K. ruwenzoricus ( Fig. 86 ), apical stylomere of which in lateral view is noticeably narrowed apically. Kenyacus pusillus sp. n. also differs from K. similis sp. n. in elytral sutural angle narrowly rounded at tip.

Figures

FIGURE 82. Kenyacus, distribution. a, K. similis sp. n.; b, K. pusillus sp. n.

FIGURE 92. Bujuku valley between Nyabitaba Hut and John Matte Hut (ca. 2800–2900 m) near the type localities of K. trechoides sp. n., K. angustatus sp. n. and K. pusillus sp. n. Forest patches with Podocarpus, Hagenia and Hypericum separated by large gaps with bushes and herbaceous vegetation. Photo: Vladimir Gusarov.

FIGURES 52–54. Kenyacus, habitus (males). 52, K. angustatus sp. n. (paratype, loc. U166); 53, K. similis sp. n. (holotype); 54, K. pusillus sp. n. (holotype). Scale bar = 1.0 mm.

FIGURES 55–81. Kenyacus. 55–65, K. angustatus sp. n. (55–57, paratype, loc. U166; 58–60, holotype; 61, paratype, loc. U162; 62, 63, same, loc. U166; 64, 65, same, loc. U162); 66–73, K. similis sp. n. (66–68, holotype; 69, 70, paratype, loc. U164; 71–73, same, loc. U165); 74–81, K. pusillus sp. n. (74–76, holotype; 77, 78, paratype, loc. U133; 79–81, same, loc. U123). 55, 58, 66, 76, median lobe, dorsal view; 57, 60, 61, 68, 73, 74, same, lateral view; 56, 59, 67, 75, apex of median lobe, dorso-caudal view; 62, 64, 69, 71, 77, 79, 80, stylus, lateral view; 63, 65, 70, 72, 78, 81, laterotergite and stylus, ventral view. Scale bar = 0.5 mm.

FIGURES 14–21. Kenyacus, microsculpture (14–17, male pronotal; 18–21, male elytral). 14, 18, K. ruwenzorii (Alluaud, 1917); 15, 19, K. gusarovi sp. n.; 16, 20, K. parvus sp. n.; 17, 21, K. angustatus sp. n. Scale bar = 0.2 mm.

FIGURES 86–90. Kenyacus ruwenzoricus Basilewsky, 1955 (paratypes). 86, stylus, lateral view; 87, laterotergite and stylus, ventral view; 88, median lobe, lateral view; 90, same, dorsal view; 89, apex of median lobe, dorso-caudal view. Scale bar = 0.5 mm.