Anthracus nathani, Jaeger, 2017

Jaeger, Bernd, 2017, Five new species of the Anthracus annamensis group from the Philippines and India (Coleoptera, Carabidae, Harpalini, Stenolophina), Linzer biologische Beiträge 49 (1), pp. 585-608: 598-602

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Anthracus nathani


Anthracus nathani   nov.sp. ( Figs 27-35 View Figs 27-29 View Figs 30-35 )

T y p e m a t e r i a l: Holotype: 3 ( MCZ) labelled "Kurumbagaram / Karikal Ter. / S. INDIA III-51 / P. S. Nathan " and " HOLOTYPE 3 / Anthracus   / nathani nov.sp. / des. B. Jaeger 2017".  

The holotype is in fair condition (left mesotarsomares 4-5, right mesotarsomeres 1-5 and right metarsomeres 1-5 missing). However, it is the only male specimen within the type series which is only slightly teneral and therefore selected to be the holotype.

Paratypes: 733, 7♀♀ (MCZ, cJAE) with same locality label data as the holotype." 13, 3♀♀ (MFNB) labelled "Süd-Indien / Jan. 1951 " and "Coll. H. Korge / Karikal Territory". 2♀♀ same data but "Süd-Indien / Mai 1951 ". 13 (NME) labelled " India / Tamil Nadu / / Mettukuppam by / Neyveli (Cudalore) / 5.1.- 1.3.2008 / leg. F. Burger Lux". All paratypes additionally labelled " PARATYPE 3 or ♀ / Anthracus   / nathani nov.sp. / des. B. Jaeger 2017" [red label]. Most paratypes are slightly to moderately immature.

E t y m o l o g y: The species in named in memory of P.S. Nathan, who collected this and other interesting Stenolophina species in southern India.

D e s c r i p t i o n: General appearance as figured ( Fig. 27 View Figs 27-29 ). Body length 3.2-3.5 mm (HT 3.8 mm); width 1.2-1.4 mm.

Shiny, pronotum weakly, elytra moderately to iridescent. Head and pronotum reddish yellow or pale reddish brown, with clypeus, labrum and mandibles (inner margins and apices of the latter brown) and pronotal lateral margins paler. Elytra mainly dark brown, with first interval, lateral margin, sometimes also apex and base paler reddish yellow. Legs, palpi and first or first two antennomeres yellowish or pale yellowish brown, remaining antennomeres slightly infuscated. Ventral surface mainly reddish yellow to yellowish brown with head slightly darker, and prosternum, epipleura and sternites partly paler.

Remark: The colour description is based on the holotype and two other darker paratype specimens, most other specimens of the type series are slightly moderately immature. It maybe that fresh completely mature specimens are generally darker (as described here).

Head ( Figs 27-29 View Figs 27-29 ) including eyes rather broad (HW/PW: 0.82-0.86), with eyes markedly prominent (head 1.63-1.76 times as wide as head between eyes). Labrum rectilinear or slightly rounded at apical margin. Mandibles medium sized, not distinctly prolonged and curved, left mandible moderately sharp at apex, not thickened or truncate. Antennae rather long relative to pronotal (AL/PL: 2.41-2.62) and elytral length (AL/EL: 0.87- 0.94). Microsculpture on labrum almost isodiametric, on clypeus isodiametric to weakly transverse, on anterior half of head partly obliterated, or partly with traces of lightly to very lightly impressed isodiametric meshes, and on posterior half posterior to eyes with lightly impressed isodiametric meshes, becoming moderately transverse in front of pronotal anterior margin.

Pronotum ( Figs 27-29 View Figs 27-29 ) moderately transverse, 1.26-1.33 times as wide as long, 1.15-1.23 times as wide as head, widest in second quarter, lateral seta inserted more or less at beginning of second quarter. Apical margin almost straight or very weakly emarginate. Anterior angles narrowly rounded at tips, not or very slightly projecting forward. Sides moderately rounded to anterior angles, from widest point rectilinearly narrowed to posterior angles, which are rather widely rounded at tips. Basal margin almost rectilinear or weakly arcuate medially, and slightly oblique to posterior angles. Lateral furrows evenly narrow in apical half, becoming weakly widened in posterior third, where they are fused with the baso-lateral impressions. Baso-lateral impressions medium sized, clearly delimited from pronotal disc and median part of base, flattened to basal and lateral margin, the latter sometimes slightly reflexed. Baso-lateral impressions and other parts of pronotal surface impunctate. Median line fine, disappearing before reaching basal and apical margins. Anterior transverse impression obliterated. Microsculpture on disc with traces of lightly impressed moderately transverse meshes, at medial portion of base and apex with more moderately impressed weakly transverse and at baso-lateral impressions with moderately impressed almost isodiametric to weakly transverse meshes.

Elytra ( Fig. 27 View Figs 27-29 ) rather long, 1.56-1.64 times as long as wide, 2.69-2.89 times as long and 1.30-1.38 times as wide as pronotum, with sides weakly widened posteriorly, widest about at middle. Subapical sinuation very weak, apical tip of each elytron moderately sharp, but not denticulate. Elytral striae distinctly impressed and impunctate, scutellar striole long. Intervals rather flat on disc, becoming very slightly narrowed and moderately convex at apex. Basal pore at beginning of scutellar striole present, interval 3 in third quarter with one setiferous pore, adjoining stria 2. Microsculpture on scutellum isodiametric, on elytral intervals almost obsolete, only here and there traces of very lightly impressed transverse lines rudiments visible. Macropterous.

Metepisterna at inner margin about 1.5 times longer than wide at basal margin. Prosternum medially with 4-5, and in front of apical margin with a row of 7-8 longer setae. Prosternal process posteriorly with 2 longer and distinct setae. Abdominal sternites IV- VI with distinct and rather dense pubescence, in sternite IV often with a small smooth area laterally. Last visible sternite faintly ermarginate at apex, at apical margin with 2 longer setae in males and 4 in females.

Protarsomeres 1-4 of males moderately dilated and with distinct, biseriately arranged adhesive hairs on ventral surface. Protarsomere 4 markedly bilobed. Mesotarsomeres 1-4 of males weakly dilated and with adhesive hairs on ventral surface. Mesotarsomere 4 moderately bilobed. In females pro- and mesotarsomeres unmodified. Male profemora slightly thickened in relation to females, without a row of numerous long and fine setae at upper inner margin.

Median lobe of aedeagus ( Figs 30-35 View Figs 30-35 ) small, with apical portion rather long and broad, and apex widely rounded in dorsal aspect ( Figs 33-34 View Figs 30-35 ). In lateral aspect moderately curved ventrad with apical part rather straight ( Figs 30-32 View Figs 30-35 ) and tip of apex with peculiar shape ( Fig 30a View Figs 30-35 .) Internal sac composed of one accumulation of 3-10 smaller teeth in upper basal half, sometimes also with 1-2 smaller teeth in lower apical half, and in apical third with a group of small but distinct spines.

C o m p a r i s o n s A. nathani   nov.sp. belongs to the Anthracus annamensis   group and represents, together with A. derogatus (WALKER, 1858)   from Sri Lanka and A. indicus JAEGER, 2012   from the Indian state of Maharashtra, the smallest species with immaculate elytra, and the fourth immaculate taxon which become known from India and Sri Lanka. It differs from A. indicus   and A. derogatus   , at a first glance by larger and markedly produced eyes (index HW/HWbE> 1.62 in A. nathani   , and <1.55 in A. derogatus   and A. indicus   ), the different shape of pronotum, the elytra which are markedly longer relative to pronotal length (index EL/PL> 2.68, instead of <2.65 in the other species) and finally by the completely different external shape und internal structure of the median lobe of the aedeagus. From A. schuhi JAEGER, 2012   , the remaining immaculate species known from India, A. nathani   can be separated by smaller size, different colour of upper surface (head and pronotum reddish yellow to reddish brown, instead of blackish brown), other body proportions and different shape and internal structures of the median lobe of the aedeagus.

All other species with immaculate elytra of the A. annamensis   occur father East in continental SE Asia, Indonesia or the Philippines, and differ from A. nathani   by larger size and/or different colour and body proportions, and finally by the different shape and internal structures of the median lobe of the aedeagus (see here and JAEGER 2012).

D i s t r i b u t i o n A. nathani   is so far known only from the Tamil Nadu state in southern India, but it is obviously more widely distributed, at least in southern India.


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