Scydmaenus (Kingius) formicarum Franz
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Scydmaenus
Scydmaenus formicarum

description: Scydmaenus (Kingius) formicarum Franz
Scydmaenus (Kingius) formicarum Franz, 1975: 277.
(Figs 90–94, 196)
Type material studied. Holotype (AUSTRALIA: NEW SOUTH WALES): ♂ (Fig. 90), with labels illustrated in Fig. 196: “Gosford / N S Wales” [brownish, printed], “ Scydmaenus / (Heterognathus) / formicarum m. / det. H.Franz ” [white, handwritten and printed], “Typus” [red, handwritten], “SAMA Database / No. 25-037121” [white, printed], “SAMA Digital Image / 2OCT 2013 ” [green, printed and handwritten] (SAMA).
Additional material studied: NEW SOUTH WALES: 3 exx., Olney State Forest, 23.02.1991, from nest in ground, leg. T. Gush (ANIC, cPJ); 2 exx., Casula (ANIC).
Revised diagnosis. In male antennomere 10 as long as broad (Fig. 90); BL <1.5 mm; aedeagus in dorsal view broadened in subapical region and only slightly narrower than at base.
Redescription. Body (Fig. 90) strongly convex, elongate and relatively stout, BL 1.48 mm; pigmentation uniformly light brown including appendages; cuticle moderately glossy, covered with vestiture of setae slightly lighter than body.
Head (Fig. 90) in dorsal view transverse and somewhat subhexagonal, broadest at eyes, HL 0.25 mm, HW 0.33 mm; vertex and frons confluent and weakly convex, posterior margin of vertex nearly straight; tempora about twice as long as length of eye in dorsal view; supraantennal tubercles indistinct; frons over antennal fossae broadly subtriangular and with rounded anterior margin. Eyes small, oval, not emarginate posteriorly and oblique in relation to long axis of head. Punctures on frons and vertex fine, inconspicuous; setae short, sparse, suberect, those on tempora distinctly denser and more erect than those on frons and vertex. Genae as sparsely setose as frons and vertex, except for dense setae on lateral regions. Anterior (exposed) region of head capsule demarcated from neck region by short abrupt impression around occipital constriction, anterior margin of gular plate on neck region lacking anteriorly-directed projection. Antennae (Fig. 90) moderately long and slender, AnL 0.78 mm; two terminal antennomeres forming moderately sharply delimited club; scape twice as long as broad, distinctly broadening distally; pedicel about 1.8 × as long as broad; antennomere 3 indistinctly elongate, 4–5 each about as long as broad, 6–8 each indistinctly transverse and each strongly broadening distally, 9 weakly elongate, also strongly broadening distally, 10 about as long as broad, 11 slightly shorter than 9 and 10 combined, about 1.7 × as long as broad, nearly symmetrical.
Pronotum in dorsal view (Fig. 90) weakly elongate, broadest slightly behind anterior third, PL 0.45 mm, PW 0.38 mm; anterior margin nearly straight; anterior corners weakly marked, obtuse-angled and blunt, lateral margins rounded; posterior corners obtuse-angled and blunt; posterior margin weakly arcuate; base with narrow and indistinct posterior marginal carina and with short and diffuse longitudinal median carina accentuated by diffuse and shallow impressions at both sides. Pronotal disc covered with fine but sharply marked, sparse punctures; setae slightly longer than those on head, moderately dense, suberect. Ventrally prothorax with nearly asetose and impunctate hypomera and basisternal region much longer than procoxal rests, sparsely covered with moderately long recumbent to suberect setae.
Elytra (Fig. 90) slightly rhomboidal, broadest near middle, EL 0.78 mm, EW 0.60 mm, EI 1.29. Humeral calli small but distinctly elevated; basal impression on each elytron short and transverse, shallow; apices separately rounded. Elytral punctures shallow but distinct and dense; setae distinctly longer and more erect than those on pronotum, moderately dense. Hind wings not studied.
Legs (Fig. 90) moderately long and slender; unmodified, except for barely discernibly broadened proximal region of protarsi bearing tenent setae on tarsomeres 1–3. Protarsomere 1 about twice as long as broad, 2–4 each about as long as broad, 5 about 3 × as long as broad; meso- and metatarsi of subequal length, both distinctly longer that protarsi, each with tarsomere 1 nearly 3 × as long as broad, tarsomeres 2–4 each weakly elongate, and tarsomere 5 about 3 × as long as broad.
Aedeagus (Figs 91–94) elongate and slender, AeL 0.50 mm, in dorsal view median lobe broadest near proximal 1/4, narrowing distally but again broadening in subapical fourth, apex broadly rounded and with barely discernible median emargination; flagellum broadened in proximal region to form three consecutive symmetrical chambers; median lobe with fine setae in apical dorsal region; ostium situated in distal half of median lobe, far from its apex.
Female. Unknown.
Distribution. SE Australia: CE New South Wales (all studied specimens come from a vicinity of Sydney).
Remarks. Franz (1975) mentioned that S. formicarum differs from S. carinatus in an almost asetose dorsal side, a shorter median longitudinal carina on the pronotum, and more distinct punctures on the elytra. The holotype of S. formicarum has almost all elytral setae broken off, so it appears asetose, but the additional specimens studied have the elytral setae similar to those in S. carinatus. The median longitudinal antebasal pronotal carina is variable in length among the studied specimens and cannot be used to distinguish S. carinatus from S. formicarum. The elytral punctures in S. formicarum are similarly distinct as those in the ‘true S. carinatus ’, which was not seen by Franz, who redescribed S. carinatus based on non-type specimens preserved at BNHM, which, although tentatively identified as conspecific with the type specimens of S. carinatus, differ in finer elytral punctures (see Remarks for S. carinatus). Scydmaenus formicarum is similar to S. carinatus, but easy to distinguish by its smaller body, different proportions of antennomeres, and a different shape of the aedeagus (see Remarks for S. carinatus).
description: Published as part of Jałoszyński, Paweł, 2023, Scydmaenus Latreille of Australia: Revision of species in subgenera Choleropsis Franz, Kingius Franz, Mascarensia Franz, Parallomicrus Franz, Scottiscydmaenus Franz, and description of Ascydmaenus subgen. n. (Coleoptera, Staphylinidae, Scydmaeninae), pp. 1-75 in Zootaxa 5371 (1) on pages 35-37, DOI: 10.11646/zootaxa.5371.1.1, http://zenodo.org/record/10144644