Kenyacus ruwenzorii ( Alluaud, 1917 )

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 : 467-472

Kenyacus ruwenzorii ( Alluaud, 1917)

( Figs 1–3 , 5–14, 18 , 27a)

Tropicoritus ruwenzorii Alluaud, 1917: 95 .

Type material examined. Holotype: ♂, labelled “Museum Paris, monts Rouwenzori, zone de forets, Makitawa [! sic] (2650 m.), Ch. Alluaud 1909”, “Type” [white, with red letters]”, “Type” [on red paper], “ Tropicoritus ruwenzorii Alluaud , type, Alluaud, det.” ( MNHN) ( Fig. 2 ).

Additional material examined. Uganda: 2 ♂♂, 1 ♀, “ UGANDA, Western Region, Kasese District, 8 km NWW Nyakalengija, Rwenzori Mts. National Park, trail from Nyabitaba Hut to Mahoma Lake , 0°21.036’N 29°58.100’E, accuracy 7 m, extent 10 m, h = 2957 m, Podocarpus , Erica , bamboo, on the ridge, sifting leaf litter [3601] [Garmin 60CSx; WGS84] V.I. Gusarov 18.viii.2008 U166” ( ZMUN); 5 ♂♂, 2 ♀ (1♀ teneral), “ UGANDA, Western Region, Kasese District, 8 km W Nyakalengija, Rwenzori Mts. National Park, trail from Nyabitaba Hut to Mahoma Lake, 0°20.748’N 29°58.085’E, accuracy 6 m, extent 15 m, h = 2988 m, bamboo, Podocarpus , sifting leaf litter [3600] [Garmin 60CSx; WGS84] V.I. Gusarov 18.viii.2008 U165” ( ZMUN, ZIN).

Re-description (5 males and 3 females measured). Habitus as in Figs 1 and 3 . Large for the genus: body length 5.3–6.0 mm, width 2.2–2.4 mm.

Colour: Body brown to blackish brown, dorsal surface somewhat dull, darker than ventral surface; base of mandibles, labrum, margins of pronotum and elytra, as well as elytral suture usually paler; palpi, antennae and legs light brown or brownish yellow; antennae infuscate from antennomere 2.

Head: Comparatively large, in males HWmax/PWmax 0.75–0.78 (m = 0.77), HWmin/PWmax 0.64–0.67 (m = 0.66); in females these indices respectively 0.73–0.80 (m = 0.77), and 0.63–0.70 (m = 0.67). Eyes with large facets, only slightly convex, separated from buccal fissure at distance of width of antennomere 1, HWmax/HWmin 1.14–1.20 (m = 1.17) in males and 1.14–1.16 (m = 1.15) in females. Tempora very short and flat. Frons and vertex convex. Fronto-clypeal suture distinct, slightly impressed. Supraorbital setigerous pore located at level of posterior margin of eye, removed from supraorbital furrow at a distance of length of antennomere 2. Labrum almost straight anteriorly. Clypeus with prominent apical angles and with slightly convex apical margin between them. Mentum and submentum ( Fig. 10 ) completely fused, submentum with two setae on each side. Mandibles me- dium-sized; left mandible evenly bent in apical portion, with acute apex. Dorsal microsculpture in both sexes very distinct throughout, consisting of large isodiametric meshes. Antennae in male extending to basal edge of pronotum, with antennomeres 7–9 only slightly longer than wide; in female antennae noticeably shorter, with shorter antennomeres.

Pronotum: Slightly transverse, PWmax/PL 1.25–1.33 (m = 1.29), widest at the end of anterior third, strongly narrowed posteriorly, PWmax/PWmin 1.28–1.33 (m = 1.33); lateral seta inserted slightly before widest point. Sides rounded anteriorly, almost straightly converging from widest point to basal angles, without distinct border. Apical margin almost straight, with slightly projecting, acute or blunted, apical angles. Basal margin slightly narrower than apical margin and noticeably narrower than elytral base, deeply emarginate, almost straight medially and oblique laterally; both apical and basal margins not bordered. Basal angles large, almost right, at most only slightly blunted at tip, markedly projecting posteriorly and covering elytral base. Disc moderately convex, strongly sloped to apical angles, depressed basally and flattened at basal angles, forming latero-basal impressions distinctly delimited from other parts of disc. Lateral depressions beginning from apical angles, narrow in apical third, evenly widened after lateral seta, reaching basal margin. Basal foveae somewhat deep, reaching basal pronotal edge, usually fused basally with lateral depressions. Surface of pronotum impunctate. Anterior transverse depression distinct and long, usually deepened. Median line thin, superficial, usually reaching apical and basal margins of pronotum. Microsculpture distinct throughout, consisting of large isodiametric meshes ( Fig. 14 ).

Elytra: Oval, widest at middle, in males EL/EW 1.40–1.45 (m = 1.42), EL/PL 2.36–2.45 (m = 2.39), EW/PWmax 1.28–1.34 (m = 1.31); in females these indices respectively 1.43–1.46 (m = 1.44), 2.36–2.46 (m = 2.40), and 1.26–1.32 (m = 1.28). Humeri prominent, angularly rounded at tip. Preapical sinuation absent, but sides in apical fifth rather sharply curved and then almost straightly converging to apex (elytra obliquely truncate apically). Sutural angle in both sexes acute and somewhat sharp at tip. Basal edge markedly sinuate laterally, arcuately curving inside humerus up to lateral margin. Lateral gutter distinct, slightly widened at humerus and prolonged on elytral base to stria 5. Elytral disc convex in lateral and caudal views, depressed basally on each side between humerus and scutellum. Striae thin, impunctate, faintly crenulate, slightly impressed along entire length, their bases removed from basal elytral border. Parascutellar setigerous pore present, large. Parascutellar striole present, with apex usually connected with stria 1. Intervals slightly convex, slightly narrowed posteriorly; interval 2 almost parallel-sided or slightly widened at apex; interval 3 without discal pore. Microsculpture very distinct throughout, almost granulate, consisting of large isodiametric meshes ( Fig. 18 ).

Ventral surface of thorax and abdomen: Prosternum with 1–5 short or moderately long erect setae medio-apically. Metepisternum slightly wider than long, narrowed posteriorly. Abdominal sternites glabrous, only last visible ( VII) sternite sparsely pubescent apically in some specimens; its apical margin in both sexes with two pairs of setae, subtruncate at tip, occasionally with very shallow, indistinct incision at middle.

Legs: Metacoxae without any additional setae. Tarsi glabrous dorsally. Tarsomere 5 without setae ventrally. Meso- and metatarsomeres 1 about as long as 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 1 lacking adhesive vestiture ventrally; mesotarsomere 4 rather deeply emarginate.

Male genitalia: Median lobe ( Figs 5–8 ) stout, arcuate in lateral view, with large basal bulb. Terminal lamella short, slightly curved dorsally, without apical capitulum; in dorso-caudal view wide, triangular, narrowly rounded at apex ( Figs 9, 11 ). Internal sac without any sclerotic elements.

Female genitalia: Very small ( Figs 12, 13 ); laterotergite (hemisternite) somewhat symmetrical, membranous apically, without setae and spines. Basal stylomere elongate, setae and spines not recognized, probably absent. Apical stylomere moderately curved, slightly shorter than basal, with short thick seta at ventral edge of outer margin, in ventral view with somewhat wide base; in lateral view ( Fig. 12 ) evenly narrowed to acute apex.

Distribution ( Fig. 27a ). Originally described from one male collected in the Mubuku (Mobuko) Valley slightly above Nakitawa till 2800 m (2659 m, according to the label data) in the south-eastern part of the Rwenzori Mountains. Additional known specimens were collected in the same area on the trail from Nyabitaba Hut to the Mahoma Lake at altitudes of 2957–2988 m. This species occurs sympatrically with K. angustatus sp. n. and K. similis sp. n.

Bionomics. According to the label data, specimens were collected by sifting leaf litter in forest with Podocarpus , Erica and bamboo ( Fig. 91 ).

Comparison. Distinctly differs from other congeners in larger size (body length 5.3–6.0 mm) and in pronotum with basal angles large, almost right, at most only slightly blunted at tip, and markedly projecting posteriorly above elytral base ( Figs 1 , 3 ). Unlike other species from the Rwenzori Mountains having all slightly transverse microsculpture on elytra, the elytral microsculpture of K. ruwenzorii is more distinct, almost granulate, consisting of large isodiametric meshes ( Fig. 18 ).

Remarks. In the holotype, the ventral margin of the apical half of the median lobe of the aedeagus in lateral view is more straight ( Fig. 6 ) and its apex in dorsal view is slightly narrower ( Fig. 9 ) than in other examined specimens ( Figs 8 and 11 , respectively); there are also some differences in configuration of the internal sacs. Because only few males are available, additional collecting is needed to determine the nature of this variability.

Figures

FIGURE 27. Kenyacus, distribution. a, K. ruwenzorii (Alluaud, 1917); b, K. gusarovi sp. n.

FIGURE 91. Mahoma lake (ca. 2960 m) near the type locality of K. similis sp. n. Patches of Erica, Hagenia, Podocarpus and bamboo forest, separated by large gaps with bushes and herbaceous vegetation. Habitats of K. ruwenzorii, K. angustatus sp. n. and K. similis sp. n. Photo: Vladimir Gusarov.

FIGURES 1, 2. Kenyacus ruwenzorii (Alluaud, 1917), holotype. 1, habitus; 2, labels. Scale bar = 1.0 mm.

FIGURES 3, 4. Kenyacus, habitus (males). 3, K. ruwenzorii (Alluaud, 1917) (loc. U166); 4, K. gusarovi sp. n. (holotype). Scale bar = 1.0 mm.

FIGURES 5–13. Kenyacus ruwenzorii (Alluaud, 1917) (5, 6, 9, holotype; 7, 8, 11–13, loc. U166; 10, loc. U165). 5, 7, median lobe, dorsal view; 6, 8, same, lateral view; 9, 11, apex of median lobe, dorso-caudal view; 10, labium, ventral view; 12, stylus, lateral view; 13, 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.