Chydaeus irvinei
Creators: name: Kataev, Boris M.
name: Schmidt, Joachim
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Chydaeus
Chydaeus irvinei

description: Chydaeus irvinei (Andrewes, 1930)
(Figs 1, 2, 6–12)
Harpalus Irvinei Andrewes, 1930: 17
Type material examined. Lectotype (designated by Kataev & Schmidt, 2002: 402): ♂, labelled “ Tibet: Gautsa, 12000 ft, 4.IV.1924, Maj. R.W.G. Hingston ”, “Type” [on round piece of paper with red margin], “Everest Exp. Brit. Mus. 1924–386”, “ Harpalus irvinei Andr. Type H.E. Andrewes det.”, “ Chydaeus Chd. Kataev det. 1989”, “ Chydaeus irvinei Andr. stat. n. det. Kirschenhofer 90”, “ LECTOTYPUS Harpalus irvinei Andrewes, des. Kataev & Schmidt, 2001” (NHML).
Paralectotypes: 1 ♂, “ Tibet: Gautsa, 12000 ft, 4.IV.1924, Maj. R.W.G. Hingston ”, “Para-type” [on round piece of paper with yellow margin], “Everest Exp. Brit. Mus. 1924–386”, “ Harpalus irvinei Andr. N.E. Stork det. 1986”, “ Harpalus irvinei Andr. ” (NHML); 1 ♂, “ Tibet: Gautsa, 12000 ft, 4.IV.1924, Maj. R.W.G. Hingston ”, “Co-type” [on round piece of paper with green margin], “Everest Exp. Brit. Mus. 1924–386”, “ Harpalus irvinei Andr. Cotype H.E. Andrewes det.”, “ H.E. Andrewes Coll. B.M. 1945–97.” (NHML) (both labelled also “ PARALECTOTYPUS Harpalus irvinei Andrewes, des. Kataev & Schmidt, 2019”).
Diagnosis. Within the irvinei group, this species is recognizable by the combination of the following characters: comparatively small (length 6.4–6.5 mm, width 3.0– 3.1 mm), smaller than most other species except for Ch. minimus Kataev et Schmidt, 2002 and Ch. ganeshensis Kataev et Schmidt, 2002, apex of left mandible truncate, dorsal microsculpture very strongly obliterated, without distinct meshes on frons as well as on pronotal and elytral discs, pronotal sides with one setigerous pore, pronotal basal angle without denticle at apex, elytra not fused along suture, their sutural angle somewhat sharp at apex, metacoxa without additional setigerous or unsetigerous pore medially, male pro- and mesotarsi markedly widened, protarsus with tarsomeres 1–4 and mesotarsus with tarsomeres 2–4 bearing adhesive vestiture ventrally, median lobe of aedeagus in lateral view evenly convex along ventral margin and with relatively small folding spiny patch in apical portion of median lobe.
Re-description (male, female unknown; three males measured). Body length 6.4–6.5 mm, width 3.0– 3.1 mm. Habitus as in Figs 1 and 2.
Coloration. Brownish black; base of mandibles, labrum externally, palpi, antennae (particularly 2–3 basal antennomeres), base of tibiae and tarsi slightly paler, brown to blackish brown; dorsum shiny, not iridescent.
Head. Large, HWmax/PWmax 0.73–0.75 (m = 0.74), HWmin/PWmax 0.67–0.68 (m = 0.67), impunctate or with very fine micropunctures. Eyes weakly convex, HWmax/HWmin 1.09–1.11 (m = 1.10). Tempora short, oblique, slightly convex, sloped to neck. Clypeus shallowly emarginate anteriorly. Fronto-clypeal suture fine. Frontal foveae small, oval, prominent. Supraorbital setigerous pore situated at level of hind margin of eye, removed at a distance of about two diameters of pore from supraorbital furrow. Labrum markedly, almost angularly emarginate anteriorly. Left mandible obliquely truncate at apex (as in Fig. 13). Ligular sclerite slightly narrowed before apex; paraglossae narrow, longer than ligular sclerite and separated from it by deep notches. Antennae slender, not long, surpassing pronotal basal edge by approximately one apical antennomere, slightly widened apically, with antennomeres 4–8 about 1.6–2.0 times as long as wide. Dorsal microsculpture strongly obliterated on frons and vertex, with distinct isodiametric meshes under and behind eyes.
Pronotum. Transverse, PWmax/PL 1.48–1.50 (m = 1.49), widest at beginning of second third, markedly narrowed basad, PWmax/PWmin = 1.14–1.20 (m = 1.16); sides evenly rounded anteriorly and shallowly sinuate in basal third; each with one setigerous pore at widest point; lateral border complete, narrow along entire length. Apical margin evenly and shallowly emarginate, bordered only laterally. Basal margin somewhat rectilinear (at most slightly rounded laterally just at basal angles), entirely distinctly bordered, slightly longer than apical margin and markedly shorter than elytral base between humeral angles. Apical angle slightly protruding, narrowly rounded at apex; basal angle almost right, slightly blunted at apex, without denticle at apex. Disc moderately convex, slightly sloped towards basal angles and markedly so towards apical angles, slightly depressed along base. Lateral depressions either shallow and narrow, present in basal fifth, or almost not developed. Basal foveae oval, comparatively large, deepened, not reaching pronotal posterior edge; area between them convex. Pronotal surface finely and irregularly punctate either along all margins, with scattered punctures in central portion, or only within and around basal foveae and along sides. Microsculpture very strongly obliterated, without distinct meshes.
Elytra. Not fused along suture, somewhat convex, oval, EL/EW 1.34–1.38 (m = 1.37), EL/PL 2.63–2.71 (m = 2.67) and EW/PWmax 1.27–1.34 (m = 1.31), widest behind middle. Humerus angulate, without denticle at apex (at most with its traces poorly recognized from behind). Subapical sinuation very shallow, sutural angle almost right, somewhat sharp at apex. Basal border almost straight or slightly sinuate laterally, joining with lateral margin at distinct obtuse angle. Striae fine, slightly crenulate, slightly impressed basally and in middle portion and superficial apically. Parascutellar striole rudimentary; parascutellar setigerous pore absent. Intervals slightly convex basally and flat apically, almost not narrowed at apex, covered with scattered very fine micropunctures. Marginal umbilicate series widely interrupted at middle, consisting of five or six basal and of six to eight apical pores. Microsculpture very strongly obliterated, without distinct meshes.
Ventral side of thorax and abdomen. Prosternum covered with short and sparse pubescence anteriorly. Metepisternum slightly wider than long, slightly narrowed posteriad. Apex of last visible (VII) abdominal sternite (in male) subtruncate, with two pairs of marginal setigerous pores.
Legs. Metacoxa with neither additional setigerous pore nor unsetigerous fovea medially (Fig. 6). Tarsi dorsally glabrous and impunctate. Tarsomere 5 with three (occasionally two) pairs of latero-ventral setae. Metatarsus noticeably shorter than HWmin, with tarsomere 1 longer than tarsomeres 2 and shorter than tarsomeres 2+3. Protarsi (in male) rather strongly enlarged, with tarsomeres 2–4 much wider than long (Fig. 7), and mesotarsi (in male) markedly enlarged (mesotarsomere 1 unmodified), with tarsomeres 2 and 3 slightly wider than long (Fig. 8); ventral side of protarsomeres 1–4 and of mesotarsomeres 2–4 covered with adhesive vestiture.
Aedeagus. Median lobe (Figs 9, 10, 12) relatively large (MLL/L 0.31–0.32), robust, strongly bent just after moderately large basal bulb, evenly convex along ventral margin (lateral view). Apical orifice in dorsal position, broad, prolonged up to basal bulb. Terminal lamella in dorsal view (Fig. 11) wide and short, wider than long, with sides roundly converging, without apical capitulum, with apex narrowly rounded. Internal sac with relatively small folding spiny patch in apical portion of median lobe.
Distribution (Fig. 38, ‘red star’). Known from one locality (Gautsa) in the Greater Himalaya of southern Tibet between Sikkim and Bhutan.
Remarks. This species was originally described from specimens collected in two separate areas of the Greater Himalaya: three specimens from Gautsa in the Ngamo Chu Valley of southern Tibet (among them a lectotype was designated) and one specimen from the Rongshar Valley also in southern Tibet but about 250 km to the west of Gautsa, all collected during the Third Mount Everest Expedition, 1924. In the original description, Andrewes (1930: 17) also mentioned a specimen without label in the collection of the Madrid Museum of Natural Sciences, which, in his opinion, probably came “from the Sikkim-Tibet frontier near the Jelep La” [to the south of Gautsa]. He also stated that “in the Rongshar Valley example the prothorax is almost impunctate, and the hind angles of the prothorax project a little laterally”. The re-examination of the type series conserved in NHML revealed that the specimens (all males) from Gautsa and from the Rongshar Valley belong to two different taxa. The male from Rongshar Valley is distinguished from the males from Gautsa in genitalia, among other characteristics, and very similar in this respect to the specimens of Ch. loeffleri from the geographically adjacent Rolwaling Valley in Central Nepal although it has some peculiarities in its morphology. Therefore it is appropriate to treat it within the latter species as a separate subspecies (see remarks under Ch. loeffleri tibetanus ssp. n. below). The mentioned specimen from the Madrid Museum was not examined and its status remains obscure.
description: Published as part of Kataev, Boris M. & Schmidt, Joachim, 2019, New data on the irvinei group of Chydaeus of the Himalaya from Nepal and southern Tibet (Coleoptera, Carabidae, Harpalini), pp. 202-214 in Zootaxa 4686 (2) on pages 203-206, DOI: 10.11646/zootaxa.4686.2.2, http://zenodo.org/record/3490084