Euconnus angusticeps
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Euconnus
Euconnus angusticeps

description: Euconnus (s. str.) angusticeps (Nietner)
(Figs 25, 45–46)
Scydmaenus angusticeps Nietner, 1856: 553.
Euconnus (Euconnus) angusticeps (Nietner); Csiki, 1919: 45.
Type material. Lectotype (here designated): ♂, three labels: “ Ceylon / Nietner..s” (white, printed and handwritten, text in black frame], QR code label with collection number 8183, and newly added “ EUCONNUS / (s. str.) / angusticeps (Nietner, 1856) / LECTOTYPUS / P. Jałoszyński, 2025 ” (MIZ).
Revised diagnosis. Vertex in lateral view weakly bulging posterodorsad and with dense thick bristles, in dorsal view vertexal region conspicuously long; eyes large but in lateral view much shorter than tempora; antennal clubs tetramerous but antennomere 7 also enlarged in relation to proximal flagellomeres, club longer than remaining flagellomeres combined; pronotum widest slightly behind middle, strongly narrowing anteriorly and weakly posteriorly, with two lateral pairs of antebasal pits connected by shallow transverse groove, and with distinct and sharply marked sublateral carinae; legs of male lacking any modifications; aedeagus in ventral view stout, broadest in subapical region, apical region subtriangular with broadly rounded distal margin and concave lateral margins; endophallus slightly asymmetrical, with large median subtriangular plate; parameres not reaching apex of median lobe.
Redescription. Body of male (Fig. 25) moderately slender, strongly convex, dark brown with slightly darker pronotum and head; setae distinctly lighter than cuticle; BL 1.93 mm.
Head broadest across eyes, HL 0.43 mm, HW 0.35 mm; frontal and anterior vertexal regions confluent, weakly convex, vertexal region weakly bulging posterodorsad, conspicuously long; supraantennal tubercles weakly elevated; eyes large but in lateral view much shorter than tempora. Punctures on frons and vertex fine and inconspicuous; setae sparse, short and weakly suberect; tempora and vertex with dense and long bristles directed posteriorly. Antennae slender, with sharply delimited tetramerous clubs longer than remaining flagellomeres combined, AnL 0.83 mm; antennomere 1–2 each strongly elongate, 3–10 each weakly transverse, 11 as broad as 10, distinctly shorter than 9–10 combined, about 1.6 times as long as broad.
Pronotum semielliptical, broadest slightly behind middle; PL 0.50 mm, PW 0.44 mm; anterior margin strongly rounded and confluent with lateral margins, which are rounded and anteriorly much more strongly convergent than posteriorly; posterior corners obtuse-angled and blunt; posterior margin straight; base with two lateral pairs of small round 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 near middle; EL 1.00 mm, EW 0.75 mm, EI 1.33; 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, lacking any peculiar modifications.
Aedeagus (Figs 45–46) stout and in lateral view weakly curved; AeL 0.28 mm; median lobe in ventral view broadest in subapical region, apical region subtriangular with broadly rounded distal margin and concave lateral margins; endophallus slightly asymmetrical, with large median subtriangular plate laterally and proximally adjacent to large asymmetrical, approximately U-shaped sclerite; parameres slender, distally straight, not reaching apex of median lobe, each with two long apical setae.
Female. Unknown.
Distribution. Sri Lanka, near Colombo.
Remarks. Only one specimen is present in Nietner coll., a male, which matches the description except for the transverse antebasal groove connecting the inner pair of pits, which was not mentioned by Nietner. Because the number of studied specimens was not specified, this male must be treated as a syntype, and here it is designated as the lectotype.
Euconnus latipennis (Motschulsky, 1858) was placed as a junior synonym of E. angusticeps by Csiki, 1919: 45, but later Franz, 1982: 164 treated E. latipennis as a separate species. He did not mention E. angusticeps, so it remains unclear whether his decision regarding E. latipennis was intentional or simply a result of overlooking the Csiki’s synonymy.
Euconnus angusticeps has the aedeagus (including endophallus) most similar to that illustrated for E. alloceylonensis Franz, 1982. However, Franz described the latter species as having the head as wide as long and antennae gradually thickening distally, while the head of E. angusticeps is conspicuously elongate and the antennae have distinct clubs.
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 96-97, DOI: 10.11646/zootaxa.5633.1.4, http://zenodo.org/record/15372835