Oesyperus planus Andrewes 1923
Creators: name: Kataev, Boris M.
Publisher: name: Zenodo
Year: 2006
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Oesyperus
Oesyperus planus

description: Oesyperus planus Andrewes, 1923
(Figs 2, 4, 9–11)
Oesyperus planus Andrewes, 1923: 446. Type locality: "Madras: Madura, Shembaganur", India.
Type material. Holotype: ɗ, labelled "Shembaganur, India, 6–1908", "29", "Ex coll. Touzalin", " Type ", " Oesyperus planus Andr., Type, H.E. Andrewes det.", "H.E. Andrewes Coll., B. M. 1945–97 " (NHML).
Redescription (based on the holotype). Size: Length 10.3 mm, width 4.1 mm.
Habitus: Fig. 2.
Colour: Body dark, almost black, slightly shiny on dorsum, with labrum and extremely narrow lateral margins of pronotum slightly paler; palpi, antennae and legs reddish brown.
Head: Medium sized (WHmax/WPmax = 0.70; WHmin/WPmax = 0.57), with small, moderately convex eyes separated from buccal fissure ventrally by distance slightly shorter than length of second antennomere. Temples long, weakly convex, sloping to neck constriction. Frontal suture narrow and shallow, clypeo­ocular prolongations superficial, rather strongly curved to sides at clypeus. Supraorbital furrows (Fig. 4) almost straight, rather strongly prolonged to neck constriction behind eyes and very weakly curved ventrad distally. Labrum rather strongly emarginate anteriorly. Penultimate labial palpomere slightly longer than apical. Puncturation of dorsal surface of head coarse, sparse and irregular, more dense on lateral areas near eyes (with distance between punctures there approximately equal to their diameter). Dorsal microsculpture distinct throughout, consisting of isodiametric meshes.
Pronotum: Weakly and evenly convex, comparatively long, 1.26 times as long as wide, widest before middle (WPmax/WPmin = 1.31). Apical margin arcuately emarginate. Apical angles markedly protruding, almost rectangular, blunt at apices. Basal margin approximately equal to apical margin, a little narrower than base of elytra between humeral angles, straight medially, clearly oblique laterally, indistinctly bordered at basal angles. Sides rounded anteriorly, nearly rectilinearly converging in basal half, throughout very narrowly bordered. Basal angles very obtuse, blunt at apices. Areas at basal angles flat. Basal foveae small, very shallow and indistinct. Dorsal puncturation more or less regular (slightly more dense along margins), with distance between punctures approximately equal to their diameter. Microsculpture distinct throughout, consisting of isodiametric meshes along margins and weakly transverse meshes on disc.
Elytra: Oblong­oval, rather long, 1.54 times as long as wide, 2.52 times as long and 1.30 times as wide as pronotum, comparatively flat basally and moderately convex apically; base of each elytron with depression between scutellum and humeral angle. Humeri prominent, rather widely rounded at apices. Preapical sinuation distinct, moderately deep. Sutural angle acute, very narrowly rounded at apex. Basal bead pubescent, rather strongly sinuate laterally, forming with lateral margin slightly obtuse angle with narrowly rounded apex. Striae impunctate, comparatively wide, shallow basally, evenly becoming deeper to apex. Parascutellar striole rather long, with distinct basal pore isolated from basal bead. Intervals rather strongly narrowed posteriad, rather flat basally, convex apically. Eighth and ninth intervals notably widened at apex. All intervals rather finely and regularly punctate, with three punctures in transverse row on each intervals on disc. Third interval with 7–9 discal pores not connected with second stria. Microsculpture distinct throughout, consisting of isodiametric, nearly granulate meshes.
Legs: Protibia with one preapical spine on outer margin; apical spur approximately as long as first protarsomere. Metafemur with two setigerous pores along posterior margin. First metatarsomere much longer than second (metatarsomeres 3–5 absent in holotype).
Male genitalia: Median lobe of aedeagus (Figs 9–11) arcuate, with weakly convex ventral margin of medial portion (lateral aspect). Terminal lamella (Fig. 10) short, slightly wider than long, with sides roundly converging to rather widely rounded apex. Apex of terminal lamella rather strongly bent dorsad forming a hook. Apical orifice extending up to basal bulb.
Distribution. Known only from the type locality (Madras: Madura, Shembaganur) in southern India.
Remarks. This species was described from two specimens collected at the same locality. In size, Oe. planus is similar to Oe. unctulus, but distinctly differs from it in the more elongate body with pronotal sides not sinuate basally. These two species seem to be more closely related to each other than any one of them to Oe. pygmaeus since both possess very similar male genitalia and share some other distinctive characters (for example, a distinct parascutellar striole and a basal depression on each elytron between scutellum and humeral angle). On the other hand, The pronotum and elytra of Oe. planus are more regularly and finely punctate than those of Oe. unctulus and Oe. pygmaeus.
description: Published as part of Kataev, Boris M., 2006, A taxonomic review of the genus Oesyperus (Coleoptera: Carabidae: Harpalini), pp. 43-55 in Zootaxa 1286 on pages 50-51, DOI: 10.5281/zenodo.173499