Trichotichnus (Bottchrus) newtoni, Kataev, Boris M., 2016

Kataev, Boris M., 2016, On taxonomic status of Bottchrus, with a description of a new brachypterous species of the genus Trichotichnus (Coleoptera: Carabidae) from the Philippines, Zootaxa 4061 (1) : -

Trichotichnus (Bottchrus) newtoni sp. n.

( Figs 10–16 )

Type material. Holotype: ♂, "E. slope Mt. McKinley, Davao Province, MINDANAO 5200' lot # 15 VIII:22:46", "CNHM-Philippine Zool. Exped. (1946–47) F.G. Werner leg." (FMNH).

Paratypes (n = 8): 1 ♀, "E. slope Mt. McKinley, Davao Province, MINDANAO lot # 8 5200' 21:VIII:46", "CNHM-Philippine Zool. Exped. (1946–47) F.G. Werner leg.", "sifting humus" (FMNH); 1 ♂, 3 ♀♀, "E. slope Mt. McKinley, Davao Province, MINDANAO VIII:2:46", "CNHM-Philippine Zool. Exped. (1946–47) F.G. Werner leg.", "in logs", " 5400 ft " (FMNH); 1 ♀, "E. slope Mt. McKinley, Davao Province, MINDANAO IX:46", "CNHM- Philippine Zool. Exped. (1946–47) H. Hoogstraal leg." (FMNH, ZIN); 1 ♂, 1 ♀ (teneral), "E. slope Mt. McKinley, Davao Province, MINDANAO 5600' 19:VIII:46", "CNHM-Philippine Zool. Exped. (1946–47) H. Hoogstraal leg.", "under moss on trees mossy forest" (FMNH, ZIN).

Description. Habitus as in fig. 10. Body length 5.5–6.1 mm, width 2.4–2.7 mm; in holotype, 5.5 and 2.4 mm, respectively.

Colour. Body piceous brown to almost black, shiny on dorsum, slightly iridescent along margins of pronotum and elytra in some specimens; labrum, base of mandibles, very narrow lateral margins of pronotum and epipleurae of elytra usually slightly paler; palpi, antennae and legs brownish yellow.

Head. Comparatively large (HWmax/PWmax = 0.74–0.78; HWmin/PWmax = 0.60–0.66), impunctate, with large, very moderately convex eyes (HWmax/HWmin = 1.21–1.23 in male and 1.15–1.21 in female). Tempora comparatively long, about 0.3-0.4 times as long as eye, flat or slightly convex, sloped to neck. Genae rather wide, noticeably wider than width of antennomere 1, glabrous. Lateral margin of head between antenna and eye slightly protruding laterally, deeply bordered, forming convex bead along external ridge. Fronto-clypeal suture and frontoocular furrows rather deep, the latter continuing along inner margin of eyes up to their posterior margin. Supraorbotal setigerous pore located at level of posterior margin of eye, removed from its inner margin by width of antennomere 3. Labrum slightly concave anteriorly. Clypeus almost straight along anterior margin, slightly depressed apically and moderately convex basally. Mentum ( Fig. 11 ) with acute medial tooth and narrow epilobes, separated from submentum by complete transverse suture. Submentum with one pare of long seta laterally. Ligular sclerite narrowed apicad, with two ventral setae just at apex. Paraglossae comparatively narrow, rounded at apex, slightly removed apically from ligular sclerite. Labial penultimate palpomere about as long as apical palpomere, with two long and one shorter setae along anterior margin. Left mandible moderately curved apically, somewhat acute at tip. Dorsal microsculpture strongly obliterated and meshes indistinct. Antennae short, extending to basal fifth of pronotum, with antennomeres 4–8 only slightly longer than wide.

Pronotum. Relatively long (PWmax/PL = 1.27–1.37), widest in apical third (PWmax/PWmin = 1.23–1.30), with one lateral seta slightly before widest point. Sides very narrowly, evenly bordered throughout, rounded in anterior two thirds, slightly sinuate in posterior third. Apical margin very slightly emarginate, bordered only laterally. Apical angles slightly protruding, acute, narrowly rounded at tip. Basal margin nearly straight medially, slightly oblique laterally, not bordered and not ciliate along basal edge, approximately equal to apical margin and slightly shorter than base of elytra between humeral angles. Basal angles slightly more than right, somewhat sharp at tip. Pronotal disc convex, rather strongly sloped to apical angles, distinctly depressed latero-basally. Basal foveae flat, poorly delimited, area between them evenly convex. Surface rather coarsely and somewhat densely punctate in wide area along margins; distance between punctures approximately equal or greater than their diameter; punctation coarser and denser latero-basally. Microsculpture usually absent, in some specimens strongly obliterate wide meshes recognizable along sides apically.

Elytra. Oval (in male, EL/EW = 1.38–1.45; EL/PL = 2.16–2.26; EW/PWmax = 1.19–1.23; in female, these indices 1.33–1.40, 2.28–2.36, 1.22–1.29, respectively), widest slightly behind middle, with acute apex. Humeri prominent, angularly rounded, without denticle at tip. Subapical sinuation very shallow. Sutural angle acute, blunted at tip. Basal edge slightly and evenly sinuate, forming a distinct obtuse angle with lateral margin. Striae slightly crenulate, deepened throughout. Intervals impunctate and glabrous, moderately convex, only slightly narrowed to apex. Parascutellar striole very short, often connected with stria 1; parascutellar pore present, large. Interval 3 with one small discal setigerous pore at striae 2 in or just behind middle. Marginal series of setigerous pores (umbilacate series) widely interrupted at middle, with 5-6 pores in anterior group and 7–10 pores in posterior group. Microsculpture largely absent, at most with indistinct, strongly obliterate meshes in humeral area.

Wings. Reduced to tiny scales.

Ventral surface. Prosternum finely pubescent. Metepisternum ( Fig. 12 ) wider than long, strongly narrowed posteriad. Abdominal sternites glabrous, only area between metacoxae covered with very short and fine setae. Apex of last visible abdominal sternite slightly truncate in male, rounded in female, with two pairs of marginal setae in both sexes.

Legs. Metacoxa with or without postero-medial seta. Protibia without longitudinal sulcus on upper surface. Profemur with five or six setae on anterio-ventral margin. Metafemur with two setae along posterior margin. Tarsi short, metatarsus shorter than HWmin, with metatarsomere 1 approximately as long as metatarsomeres 2+3. Dorsal surface of each tarsomere with few rather long setae mainly at its apical margin. Tarsomere 5 with two pairs of ventro-lateral setae. Pro- and mesotarsi of male moderately widened; mesotarsomere 1 without adhesive scales ventrally.

Female genitalia ( Figs 13–14 ). Laterotergite symmetrical, membranous apically, without spines or setae. Basal stylomere moderately widened apicad, with one preapical spine on external margin. Apical stylomere elongate, moderately curved, with a peg-like spine at both ventral and dorsal edges of outer margin.

Male genitalia. Median lobe ( Figs 15–16 ) somewhat slender, with relatively small basal bulb, rather strongly curved ventrad in basal half, with nearly straight ventral margin in apical half (lateral aspect). Terminal lamella narrow and only slightly narrowed apicad in dorsal aspect, bent dorsad at apex, in lateral aspect forming a rather big hook apically. Apical orifice shifted to left. Internal sac without any sclerotic elements.

Etymology. Named after the famous coleopterist Alfred F. Newton (Chicago), who helped to realize my visit to the Field Museum of Natural History, Chicago, where I was able to study the very interesting collections of Harpalini , including the type series of the new species.

Distribution. Known only from the McKinley Mount, Mindanao, Philippines. Because the species is brachypterous, its distribution seems to be rather local.

Bionomics. According to the label data, the specimens of this new species were collected in the mountain forest on elevation about 1585–1710 m "sifting humus" and "under moss on trees mossy forest".

Remarks. This new species is rather dissimilar to other known species of the subgenus. The transverse metepisternum ( Fig. 12 ) and small size (5.5–6.1 mm) distinctly distinguish T. (B.) newtoni sp. n. from T. (B.) philippinus and other species of Bottchrus known from the Philippines, which all are longer than 7.0 mm and have metepisternum longer than wide or at most as long as wide (Ito 1997b). In the same characters, this new species also differs from most other species of Bottchrus , most members of which are larger in size, have elongate metepisternum and normally developed wings. However, having a small body and transverse metepisternum, the new species is somewhat similar to T. (B.) amazeus from Ethiopia and several species related to T. (B.) hingstoni Andrewes, 1930 distributed in the Himalayan region, some of which are yet undescribed. Trichotichnus (B.) newtoni sp. n. is distinguished from these Ethiopian and Himalayan species by the very peculiar habitus ( Fig. 10 ) with much larger head and relatively longer pronotum and by the characteristic median lobe of aedeagus hooked at apex ( Fig. 15–16 ). It should be remarked that all these brachypterous species with short metepisternum from Ethiopia, the Himalayan region and the Philippines do not apparently constitute a monophyletic group, but probably arose as a result of independent evolution of members of one or several ancestral stocks to similar mountain conditions. Trichotichnus (B.) amazeis isolated in the forest mountains of Ethiopia may be treated as a relict of the ancient dispersal of Bottchrus to East Africa from South Asia through the Arabian Peninsula in the Tertiary time. Further investigations of the phylogenetic relationships among the recent Bottchrus species will offer a clearer view of genesis of this subgenus.

Figures

FIGURE 10. Trichotichnus (Bottchrus) newtoni sp. n. (male paratype), general view. Scale = 1.0 mm.

FIGURES 11 – 16. Trichotichnus (Bottchrus) newtoni sp. n. (11 – 14, paratype; 14 – 15, holotype). 11, labium; 12, left metepisternum; 13, apical stylomere; 14, right laterotergite and stylus; 15 – 16, median lobe of aedeagus. 11 – 12, 14, ventral view; 13, 15, lateral view; 16, dorsal view. Scale = 0.5 mm.