Euconnus graminicola Jałoszyński 2025, stat. rev.
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Euconnus
Euconnus graminicola

description: Euconnus (s. str.) graminicola (Nietner), stat. rev.
(Figs 26–27, 47–50)
Scydmaenus graminicola Nietner, 1856: 551.
Euconnus (Microscydmus) graminicola (Nietner), Csiki, 1919: 55. Note: Microscydmus by all other authors is treated as separate genus, which implies the combination Microscydmus graminicola.
Type material. Lectotype (here designated): ♂, three labels: “ Ceylon / Nietner..s” (white, printed and handwritten, text in black frame], QR code label with collection number 8191, and newly added “ EUCONNUS / (s. str.) / graminicola (Nietner, 1856) / LECTOTYPUS / P. Jałoszyński, 2025 ” (MIZ).
Revised diagnosis. Vertex not bulging posterodorsad and with thick bristles mainly laterally; eyes large, in lateral view about as long as tempora; antennal clubs trimerous, not infuscate, slender, antennomeres 9 and 10 each about as long as broad; pronotum widest near base, with one lateral pair of antebasal pits connected by shallow transverse groove, and with distinct and sharply marked sublateral carinae; protibia of male distinctly curved inwards at apex; aedeagus in ventral view broadest in sub-basal region, with dorsal and ventral apical plates abruptly demarcated laterally from basal capsular portion of median lobe, dorsal plate in lateral view distinctly recurved; endophallus with symmetrical set of poorly defined subapical structures; parameres not reaching apex of median lobe.
Redescription. Body of male (Figs 26–27) moderately slender, strongly convex, light to moderately dark brown; setae distinctly lighter than cuticle; BL 1.28–1.33 mm.
Head broadest across eyes, HL 0.25 mm, HW 0.28–0.30 mm; frontal and anterior vertexal regions confluent, weakly convex, vertexal region not bulging posterodorsad; supraantennal tubercles barely marked; eyes large, in lateral view about as long as tempora. Punctures on frons and vertex fine and inconspicuous; setae sparse, short and weakly suberect; tempora and lateral regions of vertex with dense and long bristles directed posteriorly. Antennae slender, with sharply delimited trimerous clubs, AnL 0.68 mm; antennomere 1–2 each strongly elongate, 3 and 4 each distinctly elongate, 5–10 each about as long broad, 11 as broad as 10, much shorter than 9–10 combined, about 1.8 times as long as broad.
Pronotum subtrapezoidal, broadest near base; PL 0.28–0.33 mm, PW 0.28–0.30 mm; anterior margin arcuate, anterior corners poorly marked, obtuse-angled and blunt; lateral margins weakly rounded; posterior corners obtuse-angled and blunt; posterior margin straight; base with two small round lateral pits connected by shallow transverse groove, and with strongly developed sublateral carinae. Punctures on pronotal disc similar to those on frons and vertex, inconspicuous; setae moderately long, moderately dense and suberect, lateral margins with dense and long bristles.
Elytra together oval, broadest slightly anterior to middle; EL 0.75 mm, EW 0.53–0.55 mm, EI 1.36–1.43; humeral calli distinctly elevated, basal impressions shallow but distinct; elytral apices separately rounded. Punctures and setae similar to those on median region of pronotal disc.
Legs moderately long, slender, protibiae with apices distinctly curved inwards.
Aedeagus (Figs 47–50) moderately stout;AeL 0.23 mm; median lobe in ventral view approximately drop-shaped, broadest in sub-basal region, narrowing distally and in subapical region abruptly narrowed so that subtriangular apical area is sharply delimited from basal capsule; ventral plate short and subtrapezoidal, dorsal plate much longer and with subtriangular apex; in lateral view dorsal plate distinctly recurved; endophallus symmetrical, with poorly defined subapical sclerites; parameres in ventral view slender, weakly curved and their apices not reaching apex of median lobe, each with two long apical setae.
Female. Unknown.
Distribution. Sri Lanka, near Colombo.
Remarks. Three specimens, all males, are present in Nietner coll., originally mounted on one card. Nietner (1856) stated that he collected them “in the sweeping net on the lawns of my garden about sunset.” External features of the specimens agree with the original description (especially the trimerous antennal club). The male bearing the original locality label is here designated as the lectotype of Scydmaenus graminicola Nietner. Moreover, one specimen found in a tray with a label “ glandulifer ” is a male that also belongs to E. graminicola (Nietner) (Figs 27, 49–50), but is very likely not a part of the type series of S. graminicola.
Franz (1982) did not mention the name “ graminicola Nietner ”, but he described as new Euconnus graminicola, and the aedeagus of his species is clearly different from that of E. graminicola (Nietner). Placing Scydmaenus graminicola in Euconnus (ex Microscydmus) causes a secondary homonymy with Euconnus graminicola Franz, 1982: 157. The latter name is a junior homonym and is replaced here by Euconnus graminicolides nom. nov.
Euconnus graminicola has the aedeagus almost identical with that of E. pyriformis (Figs 51–52), only the apical region in lateral view is more profoundly recurved (Fig. 48 vs. Fig. 52). Externally these species clearly differ in body size (E. graminicola is larger), size of the eye (distinctly larger in E. graminicola in relation to temple), in the structure and color of antennal clubs (in E. graminicola distinctly slenderer and not infuscate, with antennomeres 9 and 10 each as long as broad, vs. infuscate and transverse in E. pyriformis), and in bristles on the head (in E. graminicola distinct, dense and long on tempora and lateral areas of vertex, in E. pyriformis barely discernible, sparse and mainly in genal regions). These species are very similar to some other Asian species with trimerous antennal clubs, especially those that occur in East Palaearctic (Jałoszyński 2022a, b). This group of species requires study based on a larger number of specimens than have been available so far in order to verify separate status of its members. See also Remarks for E. pyriformis below.
description: Published as part of Jałoszyński, Paweł, 2025, John Nietner collection of Sri Lankan Scydmaeninae (Coleoptera, Staphylinidae), pp. 79-109 in Zootaxa 5633 (1) on pages 97-98, DOI: 10.11646/zootaxa.5633.1.4, http://zenodo.org/record/15372835