Dyschirius (Dyschiriodes) rekawaianus, Balkenohl, 2021

Balkenohl, Michael, 2021, On the subfamily Scaritinae BONELLI, 1810 from Sri Lanka, with the description of a new species (Coleoptera, Carabidae, Scaritinae), Linzer biologische Beiträge 53 (1), pp. 33-43 : 39-41

Dyschirius (Dyschiriodes) rekawaianus nov.sp. ( Figs 1-5 )

T y p e m a t e r i a l: Holotype: ♂, with labels and data: white, printed in black, " Sri Lanka, S, Rekawa E of Tangalle, 4mNN 6°03’43"N 80°52’24"E 05.01.2018 local collector leg." ( CBB). Paratypes: 4♂♂, 7♀♀, 16 specs, same data as holotype ( OLML, CBB).

E t y m o l o g y: The name refers to the region in the very South of Sri Lanka East of

Tangalle, where the species was found.

D i a g n o s i s: A medium sized species without a vertical transverse slot ventrally on the peduncle of the mesothorax, without a central tooth on the clypeus, and with a distinct keel on the frons of the head. The reflexed lateral margin of the pronotum reaches over the posterior setigerous puncture, on the elytron with three dorsal, three subhumeral, three umbilical and one subapical setigerous punctures, without a basal border and with a minute humeral tooth. Distinguished from the bengalensis -species group mostly by the single apical and three dorsal setigerous punctures. Different from D. tamil ANDREWES, 1929 by the stria seven which is not shorter than the inner striae, stria eight which is complete and distinctly punctured, the movable spur of the front tibia which is stronger and hook-like developed, the lobes of the mentum with the regularly convex median and lateral margins (in D. tamil the median margins are straight and parallel), the intervals of the elytron which are slightly convex and not as flattened as in D. tamil , and by the much darker color at the apex of the elytron. From the species with more or less similar ovate outline of the elytron D. nitens PUTZEYS, 1878 and D. hingstoni ANDREWES, 1929 , the new species differs mainly in a different pattern of the setigerous punctures, the color of the antennae, and the missing keel on the frons of the head.

D e s c r i p t i o n: Measurements: Body length 2.83-3.48 mm ( = 3.15 mm *), width 0.91-1.12 mm ( = 1.02 mm *), ratio L/W of pronotum 0.94-0.98 ( = 0.96*), ratio L/W of elytra 1.63-1.68 ( = 1.66*); (*n = 10).

Colour: Fuliginous with slight aeneous lustre; clypeal wings and margin of supraantennal plates translucent fuscous, reflexed lateral margin at apex of elytron fuscous; antennae, palpi, and legs fulvous; mandibles, labrum, and anterior legs distinctly darkened.

Head ( Fig. 2 ): Anterior margin of clypeus straight to indistinctly convex (see variation), wings of clypeus moderately projecting, hollowed out dorsally; clypeus, wings of clypeus, and supraantennal plates reflexed margined; clypeal wings separated from supraantennal plates by distinct notch; clypeo-frontal field convex, posteriorly stretched out in a triangle like longitudinal keel, with irregular rugae laterally to keel; supraantennal plates slightly to moderately vaulted, with irregular rugae posteriorly; facial sulci deep and relatively narrow, distinctly divergent posteriorly; frons moderately convex, smooth, glossy, with sparse micro-punctures. Eyes large, nearly hemispherical. Neck with some punctures laterally, punctures interrupted at middle. Labrum V-like incised, irregularly to isodiametrically reticulated. Antennae elongate (L/W around 1.25).

Mentum ( Fig. 3 ): Surface with distinct oblique rugae, with lobe slightly concavely hollowed out, shape of lobe regularly semi-ovate with lateral and medial margins convex, median tooth much shorter than lobes, triangular, indistinctly hollowed out and reflexed margined.

Pronotum: Subglobose, slightly broader than long, two thirds as wide as head; disk in frontal view moderately and equally convex, in lateral view slightly convex in anterior two thirds, distinctly convex in posterior third; outline in dorsal view moderately and nearly equally convex, attenuated directly towards anterior angles, widest slightly behind middle; anterior angles rounded off; anterior transverse impression distinct, deep, consisting of irregular punctures of different size; median line fine, narrow, shallow anteriorly and at middle; somewhat deeper towards base; reflexed lateral margin reaching over posterior setigerous puncture by diameter of puncture; lateral channel moderately broad and of equal width. Surface glossy, sparsely scattered with minutely stinged punctures, with few fine and irregular transverse wrinkles laterally and at median line.

Elytron: Ovate, around 1.7 times as long as wide (see measurements); in frontal view distinctly and equally convex, in lateral view slightly but distinctly convex in anterior two thirds; outline moderately widened at sides, widest just behind end of first third; base slightly convex, humerus prominent but rounded, with a minute humeral tooth (lateral view), suture slightly impressed at base; no basal border, no basal tubercle, scutellar striole fine but visible. Striae moderately deep in anterior half, prominently punctate, punctures distinctly smaller than width of intervals, usually not connected in basal third, finer in apical third but visible up to apex, with fine and less punctures in apical third; stria seven not shortened but fine at apex, stria eight starting at end of first quarter, continuously punctured nearly up to apical fold, one running up to base and connected with the prominent basal setigerous puncture; intervals slightly convex, flattened apically. Three posthumeral and three umbilical setigerous punctures, interval three with three dorsal setigerous punctures situated in the middle of the interval, one apical setigerous puncture.

Hind wings: Fully developed.

Ventral surface: Peduncle of mesothorax without vertical slot.

Legs: Protibia. Apical spine moderately long, strongly and equally curved ventrally, movable apical spur slightly longer and stronger developed than apical spine, nearly straight in basal two thirds, hook-shaped in apical third; distal marginal tooth acute, proximal one small, blunt. Surface covered with longitudinal reticulation.

Male genitalia ( Fig. 4 ): Median lobe slender and narrowed in apical quarter (ventral view), narrowed in apical fifth (lateral view). Tip of apex slightly asymmetric, ovate in cross section, rounded off. Oroficium of moderate size. Internal sac with group of short spines. Parameres asymmetric, distorted, the ventral one much longer and wider than the dorsal one, both of them asetose.

Female genitalia ( Fig. 5 ): Coxostylus elongated, slender, slightly distorted at middle, with two long nematiform seta at tip of apex; laterotergite vaulted, mediotergite wide.

Variation: One of the paratypes shows two dorsal setigerous punctures at one side (middle one missing). The anterior margin of the clypeus varies from straight to indistinctly convex.

D i s t r i b u t i o n: The species was found in the very South of Sri Lanka East of Tangalle.

E c o l o g y: Nearly at sea level and in parallel to the sea shore, there are lagoons and ponds partly surrounded by meadows. They are used by farmers for cattle. The new species was found at the muddy banks of those ponds.

Figures

Figs 1-5: Dyschirius (Dyschiriodes) rekawaianus nov.sp.; (1) habitus, holotype; (2) head, dorsal view; (3) head, ventral view; (4) male genitalia, holotype, ventral view of aedeagus (a) and parameres (b, c), lateral view of aedeagus (d); (5) female coxostyli, latero- and mediotergite.