Ablepton Frivaldszky
Creators: name: Paweł Jałoszyński
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Ablepton

description: Ablepton Frivaldszky
Ablepton Frivaldszky, 1877: 17. Type species: Ablepton treforti Frivaldszky, 1877 (monotypy).
Diagnosis. Ablepton differs from other Leptomastacini in two unique apomorphies: anterolateral corners of head capsule (i.e. sides of clypeus at each mandibular base) forming rounded lobes projecting anterolaterad (Figs 10– 11); postmesocoxal foveae directed mesad (Fig. 20); and in a combination of synapomorphies that occur in some other tribes and genera, but never all together: head, pronotum and elytra uniformly covered with setae (Fig. 1); head subquadrate (Fig. 10); 'neck' region broader than half width of head (Fig. 12); postgenae with distinct longitudinal ridges (Fig. 12; lr); each mandible with a median mesal tooth (Fig. 11); median projections of anterior and posterior margins of setose impression of mesoventrite not meeting (Fig. 24); mesoscutellum subtriangular, with pointed tip (Fig. 26); metaventrite with median longitudinal carina (Fig. 21).
Characteristics. Adult. Body (Figs 1–2) small, 1.40̄2.10 mm in length, light to moderately dark brown, flattened, sparsely setose, setae mostly modified, either flattened and broadened but strongly elongate or very short and broad, leaf-like.
Head capsule (Figs 10–12) divided into large and exposed anterior part and smaller, subcylindrical 'neck' region retracted into prothorax and demarcated by distinct occipital constriction; 'neck' region broader than half width of head. Anterior part of head flattened and about as long as broad or slightly longer, subquadrate in shape, with rounded sides of vertex, broadest behind middle but far from posterior margin. Composite eyes (Fig. 10; ce) slightly anterior to middle, on sides of head, vestigial, each composed of 2̄3 small ommatidia which are barely discernible under stereoscopic microscope. Vertex transverse, convex, with posterior margin nearly straight at middle and a pair of large lateroposterior setiferous punctures (Fig. 10; sp). Tempora long and rounded. Frons between antennal insertions subtriangular, anteriorly demarcated by deep and narrow frontoclypeal groove (Fig. 10; fcg), which is obliterated laterally. Clypeus transverse, with subtriangular and rounded lateral projections behind external margin of each mandibular base. Antennal insertions (Fig. 10; ai) laterodorsal, in submedian area of head. Gular plate (Fig. 12; gp) lacking sutures, with transverse reticulation; posterior tentorial pits (Fig. 12; ptp) C-shaped and located in front of transverse impression demarcating 'neck' region ventrally. Head densely but finely punctate and covered with sparse flat, broad and moderately long setae.
Antennae (Figs 1–2, 12, 14) much shorter than body; scape (Fig. 12; sc) only 3̄4 times as long as broad; pedicel only slightly longer than antennomere III and distinctly broadening from relatively narrow base to apex; antennomeres III–X (Fig. 14) mostly transverse and thickening distad, each with short and narrow stalk and sharp basal ring, antennomeres covered with dense and evenly distributed short and only slightly flattened setae and much longer, strongly flattened and broadened sparse setae around distal margin of each antennomere except I, II and XI, all setae inserted on small papillae, so that surface of antennomeres appears coarse.
Labrum (Figs 10–11; lbr) strongly transverse, with slightly rounded and anteriorly divergent lateral margins and concave anterior margin with deep median subtriangular emargination; dorsal surface with only several long and thick setae. Mandibles (Figs 10–12) symmetrical, each subtriangular but relatively slender, with broad base and long, curved and moderately sharp apical tooth; mesal tooth (Figs 10–11; mt) present, subtriangular and shifted dorsad; setose prostheca (Fig 11; pst) present, small. Maxilla (Figs 15–16) with large and nearly semicircular cardo (Fig. 15; cd); basistipes (Fig. 15; bst) subtriangular and elongate; mediostipes (Figs 15–16; mst) large and sharply demarcated from lacinia (Figs 15–16; lac) and galea (Figs 15–16; gal), which are both elongate and curved mesad and each bears a dense row of flattened distal setae; palpifer (Figs 15–16; ppf) broad and elongate; maxillary palp (Figs 15– 17) composed of minute palpomere I (Figs 15–16; mxp1), elongate and broadening distad palpomere II (Figs 15, 17; mxp2), and palpomeres III (Fig. 17; mxp3) and IV (Fig. 17; mxp4) forming large compact oval in which palpomere III is pedunculate and with strongly oblique apex and palpomere IV is broader than long and broadly subconical with rounded but distinctly marked apex. Labium (Fig. 15) with broad submentum (Fig. 15; smn) posteriorly not demarcated from gular region and laterally indistinctly demarcated from postcardinal portions of hypostomae by weakly marked and incomplete ridges; mentum (Fig. 15; mn) subtrapezoidal with anterior margin slightly concave; prementum (Figs 15–16; pm) long, subtrapezoidal, broadest distally, without demarcated ligula, with broadly separated bases of labial palps; lateral lobes of hypopharynx (Fig. 15; lhl) moderately large; labial palp composed of three palpomeres: palpomere I (Fig. 15; lp1) small, elongated, palpomere II (Fig. 15; lp2) largest, strongly elongated and broadened distally, palpomere III (Fig. 15; lp3) narrow, long and pointed. All mouthparts and clypeus covered with sparsely distributed porous fields (Fig. 13; pf); maxillary palpomeres IĪIV covered with elongate and only slightly broadened and flattened setae (Fig. 17).
Prothorax (Figs 1–2, 18–19) flattened and elongate, broadest near anterior third. Pronotum with all margins rounded; anterior corners not marked, posterior corners distinct, obtuse-angled; pronotal base lacking pits, impressions, grooves or carinae. Prosternum (Figs 18–19) with basisternal part (Figs 18–19; bstr) about as long or only slightly longer than coxal part (Fig. 19; cxst), laterally completely fused with hypomera and lacking any noticeable traces of notosternal sutures. Coxal region demarcated anteriorly by rounded carina extending laterally up to apices of subtriangular postcoxal hypomeral lobes (Fig. 18; pchl) projecting mesad. Procoxal cavities broadly open; profurcal foveae (Fig. 10; pff) small but distinct. Prosternal intercoxal process (Fig. 19) subtriangular and posteriorly very narrow, diffuse, indistinctly demarcated laterally and very weakly elevated, so that procoxae are not separated. Ventral surface of prothorax largely asetose and glabrous; short, broad and strongly flattened setae present along anterior and posterior margins of basisternal area (Figs 18–19).
Mesoventrite (Figs 20–24) subtrapezoidal, broadening posteriorly. Prepecti (Fig. 21; pre) long and together with anteromedian mesoventral area forming continuous 'collar', with a narrow and shallow transverse groove just behind its anterior ridge (Fig. 21; ar) and deeply bisinuate posterior margin with rounded and asetose subtriangular posteromedian expansion. Region just behind collar strongly and abruptly constricted laterally and impressed medially, forming a transverse setose impression (Figs 20–23; si) filled with dense, strongly flattened, leaf-like setae. Posterior margin of setose impression forming a large median subtriangular projection directed anterad, but not meeting with anterior projection of collar. Mesoventral intercoxal process (Fig. 21; msvp) long, narrow and weakly convex, fully separating mesocoxae, slightly narrowing posteriorly and fused with metaventrite. Mesanepisterna (Fig. 23; aest2) large and subtriangular, demarcated from mesepimera by carinate ridge; mesepimera (Fig. 23; epm2) indistinctly demarcated from metepimera and partly exposed in ventral view (Fig. 21).
Mesonotum with subtriangular and pointed mesoscutellum (Fig. 26; scl2) not visible between elytral bases in intact specimens, scutoscutellar suture absent.
Metaventrite (Figs 20–22) short, subtrapezoidal, broadest at level of metacoxae, with lateral margins rounded; mesocoxal cavities with nearly continuous marginal carina encompassing nearly entire cavity except for its external portion; posterior margin of metaventrite deeply bisinuate laterally in admetacoxal region and with a broad metaventral intercoxal process (Fig. 21; mtvp) with nearly straight posterior margin and subtriangular lateral corners weakly projecting posteriorly; metaventrite with median longitudinal carina (Fig. 21; mc) and three pairs of foveae, whose openings are filled with leaf-like setae: lateral meso-metaventral foveae (Figs 20–23; lmf) laterad mesocoxal insertions; lateral mesocoxal foveae (Figs 20; 22; lmcf) posterolaterad mesocoxal insertions; and postmesocoxal foveae (Figs 20–24; pmcf) posterad mesocoxal cavities, in submedian region of ventrite. Admetacoxal margin of metaventrite with a short thickening demarcated by a groove, forming adcoxal carina (Fig. 21; acxc). Metanepisterna (Figs 20–21, 23) partly visible in ventral view, relatively narrow, distinctly broadening posterad; metepimera (Fig. 23; epm3) about three times as broad as metanepisterna, with indistinctly demarcated inner and outer component, posteriorly extending far behind metacoxae.
Metendosternite (metafurca) Y-shaped, with very short but distinct stem and divergent lateral furcal arms (Fig. 20; lmfa), additionally with a short anteromedian projection.
Legs (Figs 1–2, 21, 25, 28) moderately long, robust. Pro- and mesocoxa short subconical, metacoxa with a nearly hemispherical basal part and subconical distal part. Mesocoxa (Fig. 25; cx2) with impressed lateral adtrochanteral area, border between concave and convex surface with a row of 3̄5 long coxal bristles (Fig. 25; cxb). All trochanters short and subtriangular. Femora weakly clavate. Tibiae robust, all nearly straight. Tarsi short, subcylindrical, tarsomeres reducing in length but not in width from I to IV, tarsomere V strongly elongate, with curved and slender claws and empodium with a pair of modified empodial setae.
Elytra (Figs 1–2, 26) oval, flattened, lacking humeral calli and basal impressions, with rounded apices; elytral disc with large and deep punctures arranged in nearly complete longitudinal rows.
Hind wings absent.
Abdomen (Fig. 20) with sternite III not fused with metaventrite, about as long as sternites IV and V together; sternite VIII in male with rounded posterior margin. Sternite III with distinct anteromedian and indistinct anterolateral (postmetacoxal) impressions filled with leaf-like setae.
Aedeagus (illustrated in (Jałoszyński et al. (2015, 2018)) symmetrical and lightly sclerotized, strongly elongate, parameres partly fused to lateral walls of median lobe, with apices strongly curved mesad; flagellum simple and broad, not coiled. Ejaculatory duct with strongly elongate and narrow sperm pump, its distal end with a sclerotized funnel-like collar.
Spermatheca (not illustrated) globular and thick-walled, nearly spherical, with 'stalk' as long as globular part and as broad as 1/3 of globular part; ductus spermathecae and duct of accessory gland inserted into the stalk.
Sexual dimorphism expressed in protrochanters, which in males are subquadrate and with a subtriangular ventral (posterior) projection (Fig. 27).
Larva. Unknown.
Composition and distribution. Only three species are known (but see Remarks), distributed in Romania and Serbia (Fig. 7).
Natural history. Some of the Serbian species of Ablepton were collected by pitfall traps with vinegar placed between roots of old beech trees on a limestone-rich ground near a stream, some others in vicinity of caves. Specimens of Ablepton treforti studied by the author were obtained by sifting leaf litter in beech forests in Romania. Nothing else is known about the natural history of this genus.
Remarks. Within Leptomastacini, Ablepton closely resembles Taurablepton. These genera can be distinguished on the basis of the following characters: the shape of head (subquadrate in Ablepton vs. subtriangular in Taurablepton); anterolateral corners of head capsule at each mandibular base (forming rounded lobes projecting anterolaterad in Ablepton vs. not projecting in Taurablepton); median projections of anterior and posterior margins of setose impression of mesoventrite (not meeting in Ablepton vs. nearly touching in Taurablepton); postmesocoxal foveae (directed mesad and very close to each other in Ablepton vs. directed anteromesad and broadly separated in Taurablepton); the mesoscutellum (subtriangular with pointed tip in Ablepton vs. subtrapezoidal with truncate tip in Taurablepton). Additionally, Ablepton has the median area of prosternum asetose, whereas in Taurablepton there are some median setae on the basisternal region.
The three species placed in Ablepton differ in so minor characters that they may in fact represent variability within one species. Nonveiller & Pavičevič (1990, 1999) stated that the two Serbian species do not differ in the structure of the aedeagus from the type species of the genus, A. treforti. Also external diagnostic characters of their newly described two Serbian species seem rather elusive. A larger material from the entire known distributional range of Ablepton must be studied to address this issue.
description: Published as part of Paweł Jałoszyński, 2018, World genera of Mastigitae: review of morphological structures and new ecological data (Coleoptera: Staphylinidae: Scydmaeninae), pp. 1-119 in Zootaxa 4453 (1) on pages 14-20, DOI: 10.11646/zootaxa.4453.1.1, http://zenodo.org/record/1454920