Keratodegnathus javanicus Jaloszynski 2024, sp. n.
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Keratodegnathus
Keratodegnathus javanicus

description: Keratodegnathus javanicus Jałoszyński sp. n.
(Figs 1–24)
Type material. Holotype: Indonesia (West Java Province): ♀, two labels: “W Java, Mt. Gede / 1400-1500m / 24-28. V. 97 / leg. S. Kurbatov ” [white, printed], “ KERATODEGNATHUS / javanicus m. / Jałoszyński, 2024 / HOLOTYPUS” [red, printed] (MHNG).
Diagnosis. Female with dark brown head, elytra and distal region of abdomen, and with red pronotum and proximal region of abdomen (Fig. 1); antennomere 11 (Fig. 1) conspicuously elongate, twice as long as 10; spermatheca (Fig. 24) with slender receptacle and a long duct tightly coiled around a large spheroid reservoir, duct coils form elongate, flat and ovoid structure.
Description. Body of female (Fig. 1) strongly flattened and slender, head, elytra, distal region of abdomen, antennomeres 1–9 and legs except tarsi dark brown with reddish hue, pronotum and proximal region of abdomen brownish-red, antennomeres 10 and 11 pale yellowish, palps and tarsi light brow; cuticle glossy; setae dark brown. BL 5.05 mm.
Head (Figs 2–6) broadly subtrapezoidal, as broad as pronotum, broadest at eyes, HL 0.63 mm, HW 1.00 mm. Eyes large and strongly convex, finely faceted, strongly elongate oval. Clypeus (Figs 4, 6; cl) nearly flat, strongly transverse and with nearly straight anterior margin; frons (Figs 4, 6; fr) subtriangular, weakly convex, broadening posteriorly, where it is confluent with strongly transverse vertex (Fig. 4; vt) slightly impressed posteromedially; supraantennal tubercles lacking, oval antennal fossae exposed dorsally. Clypeolabral connecting membrane (Figs 4, 6; cmb) about as long as labrum and subtrapezoidal. Tempora in dorsal view slightly shorter than half length of eye. Genae (Fig. 5; gen) with complete genal ridges extending from their posterior margins to the level of cardines. Gular plate (Fig. 5; gp) and submentum (Fig. 5; smn) confluent and laterally delimited by continuous gular and hypostomal sutures (Fig. 5; gs, hs), narrowest site of gula situated just behind barely discernible, narrow and elongate posterior tentorial pits (Fig. 5; ptp). Hypostomal ridges (Fig. 5; hr) complete, each extending from posterior margin of submentum (marked by anterior ends of posterior tentorial pits) to the level of anterior margins of cardines. Head largely impunctate, small setiferous punctures present only mesad and posterad antennal fossae, on tempora and on genae (mainly along genal ridges, posterior margins and gular sutures); setae sparse, moderately long and suberect, those on posterior and mesal regions of genae much shorter than those on frons and vertex.
Labrum (Figs 4, 6–7; lbr) strongly transverse, with evenly rounded anterior margin, except for shallow median emargination (Fig. 8), dorsal surface with two rows of symmetrically distributed long setae and asymmetrically, sparsely distributed minute setae. Mandibles (only partly exposed in studied specimen) long and slender, with pointed apices, each with dorsal tooth (Fig. 6; dmt). Cardo (Fig. 5; cd) strongly transverse; basistipes (Fig. 9; bst) subtriangular and elongate; mediostipes (Fig. 9; mst) subrectangular; galea and lacinia (Figs 9, 10; gal, lac) slender, with dense mesal and distal setae, galea much longer than lacinia. Maxillary palp short and slender, palpomere 1 (Fig. 9; mxp1) short, annular, palpomere 2 (Fig. 9; mxp2) strongly elongate, weakly curved and broadening distally; palpomere 4 (Fig. 9; mxp4) strongly elongate, aciculate. Submentum (Fig. 9; smn) subtrapezoidal and strongly transverse, its median region slightly impressed and with matte microsculpture contrasting with smooth lateral margins; mentum (Fig. 9; mn) subtrapezoidal, strongly transverse, covered with dense microgranules; prelabium (Fig. 9; prl) strongly elongate, with subtrapezoidal membranous proximal region and a pair of distal premental sclerites (Fig. 10; pmns) narrowly separated at middle, each bearing one short lateromedian seta and one long anterolateral seta; labial palps with palpomere 1 (Fig. 10; lp1) strongly elongate, palpomere 2 (Fig. 10; lp2) much narrower and shorter than lp1, strongly elongate, palpomere 3 (Fig. 10; lp3) narrow and long, weakly curved, nearly rod-like with rounded apex; ligula (Fig. 10; lig) bipartite, composed of two separate elongate processes, each with two apical setae; lateral lobes of hypopharynx (Fig. 10; llh) short and rounded.
Antennae (Figs 1, 4, 6) slender, AnL 2.70 mm. Scape about 4 times as long as broad, clavate, broadest near distal third; pedicel only 1/3 as long as scape and distinctly narrower, about twice as long as broad; antennomere 3 conspicuously elongate, 3 × as long as broad and broadening distally; antennomeres 4–9 each 2.2–2.5 × as long as broad, each broadening distally, antennomere 10 slightly shorter and stouter than 9, weakly broadening distally, antennomere 11 conspicuously long, slightly longer than 9 and 10 combined, almost 4 × as long as broad, gradually narrowing from base to apex. Scape and pedicel glossy, remaining antennomeres matte, densely covered with fine microreticulation, antennomeres 10 and 11 with much sparser setae than remaining flagellomeres.
Pronotum (Figs 2, 4) strongly convex, subtrapezoidal, broadest at level of anterior corners, strongly transverse; PL 0.68 mm, PW 0.95 mm.Anterior pronotal margin weakly arcuate; anterior pronotal corners slightly obtuse-angled and with rounded apices; lateral margins straight; posterior corners strongly obtuse-angled and blunt; posterior margin weakly arcuate. Entire pronotal disc smooth and with sparse, fine setiferous punctures distributed in anterior half and along lateral margins; four macrosetae present along each lateral margin (Fig. 4; indicated by arrowheads), sparse suberect setae distributed in anterior half of pronotal disc. Lateral pronotal carinae (Fig. 2; lpc) sharply marked and complete; hypomera (Figs 2, 5; hyp) exposed in lateral view, impunctate and asetose. Hypomeral ridges (Fig. 5; hyr) present, each situated close to outer margin of procoxal cavity and anteriorly connecting with lateral pronotal carina. Prosternum (Fig. 5; pst) also impunctate and asetose.
Elytra (Fig. 11) together subtrapezoidal, broadest at posterior corners; EL 0.75 mm, EW 1.30 mm. Humeri obtuse-angled and not bulging, lateral elytral margins weakly rounded and diverging posteriorly, posterior elytral margins weakly rounded, posterolateral elytral corners blunt and nearly right-angled, adsutural posterior corners obtuse-angled and rounded, elytral suture accentuated by fine adsutural carina (Fig. 11; asc) on each elytron. Elytral disc sparsely punctate, covered with short and sparse suberect setae, each elytron with longitudinal row of four macrosetae along lateral margin (Fig. 11; indicated by arrowheads).
Hind wings long.
Mesoscutellar shield largely exposed between elytral bases (Fig. 4), its visible region subtriangular, impunctate and asetose.
Legs (Fig. 1) long and slender, all tibiae straight, tarsi (Figs 13‒16) 4-5-5, increasingly longer from fore to hind, each terminal tarsomere with distoventral set of pointed processes (Fig. 18) and with single empodial seta (Fig. 18; es) inserted on elongate subcylindrical cuticular process bearing its own minute lateral seta.
Abdomen (Figs 1, 11‒12) at base indistinctly narrower than elytra, slightly longer than head, pronotum and elytra combined; AbL 3.00 mm, AbW 1.28 mm. Tergites III‒VI (Fig. 11) each with anterior transverse carina with its ends curved towards spiracle. Tergites III‒VI each with four setae along posterior margin and one pair of lateromedian setae; tergite VII with one pair of lateromedian setae and one pair of lateral setae in posterior third; tergite VIII (Fig. 20, most macrosetae broken off) elongate subtrapezoidal with transverse rows of more numerous submedian and distal setae. Tergite VII (Fig. 11) with posterior band of densely set microtrichia. Inner component of each paratergite on segments III‒VI with one minute distal seta, outer component with one long submedian seta and a group of minute distal setae. Sternites (Fig. 12) relatively densely setose; sternite VIII (Fig. 19) subtrapezoidal with rounded posterior margin. Abdominal segments IX and X (Fig. 21) with a pair of large sclerotized structures, possibly homologous with ‘vaginal plates’ of Maruyama (2006).
Abdominal glandular openings (Fig. 11). Tergite IV with minute round glandular opening (Fig. 11; go1) mesad each spiracle. Sparse single openings surrounded by five cuticular processes (Fig. 11; go2), found also only on tergite IV. Numerous minute pore plates (Fig. 11; go3) composed of 5‒6 oval or irregular openings present on all tergites, inside each opening 1‒3 microscopic pores are present.
Spermatheca (Figs 23‒24) 0.48 mm in length, with slender receptacle and a long duct tightly coiled around a large spheroid reservoir, duct coils form elongate, flat and ovoid structure.
Male. Unknown.
Distribution. Java.
Etymology. The adjective javanicus refers to the type locality.
Remarks. The female of K. rougemonti (known to occur in Sabah, Borneo) has antennomeres 10 and 11 subequal in length, whereas in K. javanicus antennomere 11 is conspicuously elongate, twice as long as 10. Moreover, the abdomen of K. rougemonti is uniformly reddish, and in K. javanicus infuscate in posterior half. The spermatheca of K. rougemonti illustrated in Pace (2014: fig. 130) is clearly incomplete, it seems that it is also partly damaged (the receptacle is not illustrated and the duct possibly distorted). The female of K. cornutus (a species inhabiting Pahang in peninsular Malaysia) has the head, pronotum and elytra nearly black, while in K. javanicus the head and elytra are dark brown, but the pronotum is contrastingly red. The spermatheca of K. cornutus (illustrated in Assing (2019: fig. 117)) is of a clearly different shape than that of K. javanicus; in addition to a different pattern and shape of coils around the large reservoir, there is a loop just proximal to the distal receptacle in K. cornutus, whereas there is no such a loop in the spermatheca of K. javanicus.
description: Published as part of Jałoszyński, Paweł, 2024, A new species of Keratodegnathus Pace in Indonesia (Coleoptera, Staphylinidae), pp. 355-364 in Zootaxa 5471 (3) on pages 356-363, DOI: 10.11646/zootaxa.5471.3.5, http://zenodo.org/record/12190170