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

description: Taurablepton Franz
Taurablepton Franz, 1988: 111. Type species: Taurablepton subterraneum Franz, 1988 (des. orig.).
Diagnosis. Taurablepton differs from other Leptomastacini in one unique apomorphy: mesoscutellum subtrapezoidal with truncated tip (Fig. 70); and a combination of synapomorphies shared with other tribes and genera, but not all together: head, pronotum and elytra uniformly covered with fine setae (Fig. 5); head subtriangular (Figs 57–58); 'neck' region broader than half width of head (Fig. 57); each mandible with a median mesal tooth; anterolateral corners of head capsule (i.e. sides of clypeus at each mandibular base) lacking projecting lobes; postgenae lacking longitudinal ridges; median projections of anterior and posterior margins of setose impression of mesoventrite nearly touching at middle (Fig. 67); postmesocoxal foveae directed anteromesad (Fig. 74); metaventrite lacking median longitudinal carina (Fig. 66).
Characteristics. Adult. Body (Figs 5–6) small, 1.10–1.50 mm, light brown or yellowish, flattened, finely setose, most setae unmodified.
Head capsule (Figs 57–58, 69; 72) 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 subtrapezoidal in shape, narrower than pronotum and broadest near posterior margin. Eyes rudimentary or absent. Vertex strongly transverse and weakly, nearly evenly convex except for posteromedian subtriangular impression, posterior margin of vertex weakly concave, with a pair of small setiferous punctures (Figs 58–59; sp). Tempora very long and rounded. Frons between antennal insertions subtrapezoidal and forming 'platform' sharply demarcated anterolaterally; frontoclypeal groove marked only at middle and obliterated laterally. Clypeus short and broad, with sides rounded and not projecting anteriorly. Antennal insertions (Fig. 58; ai) located dorsally in submedian area of head. Gular plate (Fig. 57; gp) without sutures, transversely reticulate; posterior tentorial pits (Figs 57, 72; ptp) arcuate and located in front of transverse impression demarcating 'neck' region ventrally. Head finely and densely punctate and dorsally covered with short, sparse and slightly suberect setae.
Antennae (Figs 5–6) much shorter than body; scape (Figs 57, 69, 72; sc) 3̄4 times as long as broad; pedicel (Figs 69, 72; pd) distinctly longer than antennomere III and strongly broadening from narrow base to apex; flagellomeres (Fig. 62) mostly transverse and weakly thickening distad; antennomeres covered with two kinds of setae: dense and evenly distributed short and only slightly flattened setae and much longer, strongly flattened and broadened sparse setae around distal margin; all setae inserted on small papillae, so that surface of antennomeres appears coarse. Basal rings of antennomeres III–XI (Fig. 63) finely serrate.
Labrum 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 symmetrical, each subtriangular but relatively slender, with broad base and long, curved and moderately sharp apical tooth; mesal tooth present, subtriangular and shifted dorsad in relation to the coronal plane of mandible; setose prostheca present, small. Maxilla (Figs 57, 72) with large and arcuate cardo (Figs 57, 72; cd); basistipes (Figs 57, 72; bst) subtriangular and elongate; mediostipes (Figs 57, 72; mst) large and sharply demarcated from lacinia (Figs 57, 72; lac) and galea (Figs 57, 72; gal) which are both elongate and curved mesally and each with dense row of distal flattened setae; palpifer (Figs 57, 72; ppf) broad and elongate; maxillary palp composed of minute and elongate palpomere I (Figs 57, 72; mxp1), strongly elongate and broadening distally palpomere II (Figs 57, 72; mxp2), and palpomeres III (Figs 57, 72; mxp3) and IV (Figs 57, 72; mxp4) forming large compact oval, in which palpomere III is pedunculate with strongly oblique apex and palpomere IV is shorter than broad and broadly subconical with rounded but distinctly marked apex. Palpomeres II–IV densely covered with lanceolate setae forming irregular longitudinal rows (Fig. 61). Labium (Figs 57, 72) with broad submentum (Figs 57, 72; smn) posteriorly not demarcated from gular region and laterally indistinctly demarcated from postcardinal portions of hypostomae by diffuse ridges; mentum (Figs 57, 72; mn) subtrapezoidal with anterior margin slightly concave; prementum (Figs 57, 72; pmn) long, subtrapezoidal, broadest near apex, without demarcated ligula, with broadly separated bases of labial palps; lateral lobes of hypopharynx moderately large; labial palp (Figs 57, 72; lp) composed of three palpomeres: palpomere I small, elongated, palpomere II largest, strongly elongated and broadening distally, palpomere III narrow, long and pointed. All mouthparts and clypeus covered with sparsely distributed porous fields.
Prothorax (Figs 64–66, 71, 73) flattened and weakly elongate or nearly as broad as long, broadest near anterior forth. Pronotum (Fig. 64) with all margins rounded; anterior corners not marked, posterior corners also indistinct, obtuse-angled; pronotal base without pits, impressions, grooves or carinae. Prosternum with basisternal part (Figs 66, 73; bst) about as long or only slightly longer than coxal part (Fig. 73; cxst), laterally completely fused with hypomera, but in one species barely discernible traces of notosternal sutures (Fig. 66; nss) can be seen at anterior sternal margin. Coxal region demarcated anteriorly by carina extending laterally to middle of procoxal cavities. Procoxal cavities broadly open. Prosternal intercoxal process subtriangular and posteriorly narrow, sharply demarcated laterally and very weakly elevated, in intact specimens hidden between procoxae. Ventral surface of prothorax largely asetose and glabrous; short leaf-like setae present along midline and along anterior and posterior margins of basisternal area (Fig. 65).
Mesoventrite (Figs 66, 71, 74) subtrapezoidal, broadening posteriorly. Prepecti (Fig. 74; pre) long and fused together with anteromedian mesoventral area to form a 'collar' with anteromedian transverse groove and posterior margin with rounded subtriangular posteromedian projection. Region just behind collar strongly and abruptly constricted laterally and impressed medially, forming setose impression (Figs 66, 71, 74; si), with its posterior margin forming a subtrapezoidal or subrectangular median projection nearly meeting anteromedian projection, so that setose impression is transversely 8-shaped (Fig. 67). Mesoventral intercoxal process Figs 66, 68, 74; msvp) long, moderately narrow and nearly flat, fully separating mesocoxae, distinctly narrowing posteriorly where it is variously distinctly demarcated from metaventrite (border may be indistinct under SEM, as in Fig. 68, but distinctly visible in transparent mounts, Fig. 74). Mesepimera (Figs 66, 74; epm2) partly visible in ventral view.
Mesonotum (Fig. 70) with subtrapezoidal mesoscutellum, its apex truncate, scutellum not visible between elytral bases in intact specimens, scutoscutellar suture absent.
Metaventrite (Figs 66, 71, 74) short, subquadrate or transversely subrectangular, with lateral margins rounded; mesocoxal cavities with nearly continuous marginal carina interrupted only laterally; posterior margin of metaventrite deeply bisinuate laterally and with a broad metaventral intercoxal process (Figs 66, 74; mtvp) with subtriangular posterior emargination; metaventrite with three pairs of foveae, whose openings are filled with leaflike setae: lateral meso-metaventral foveae (Fig. 74; lmf) laterad mesocoxal insertions; lateral mesocoxal foveae (Fig. 74; lmcf) posterolaterad mesocoxal insertions; and postmesocoxal foveae (Fig. 74; pmcf) posterad mesocoxal cavities, in submedian region of ventrite. Admetacoxal region of posterior metaventral margin with additional marginal thickening at each side, forming adcoxal carina (Figs 66, 74; acxc). Metanepisterna (Figs 66, 71, 74; aest3) partly visible in ventral view, distinctly broadening posteriorly; metepimera broad, not exposed in intact specimens.
Metendosternite (metafurca; Figs 71, 74) Y-shaped, with short but distinct stem and divergent lateral furcal arms (Figs 71, 74; lmfa), additionally with a short anteromedian projection.
Legs (Figs 5–6, 66, 68, 71, 74–77) moderately long, robust. Pro- and mesocoxa suboval, metacoxa with nearly hemispherical basal part and subconical distal part. Mesocoxa with impressed lateral adtrochanteral area, border between concave and convex surface with 3̄4 long coxal bristles (Fig. 68; cxb). Pro- and mesotrochanters short and subtriangular, metatrochanters distinctly elongate. Femora weakly clavate. Tibiae robust, all nearly straight. Tarsi (Figs 75–77) short, nearly subcylindrical, tarsomeres reducing in length but not in width from I to IV, tarsomere V strongly elongate, with robust claws covered with longitudinal costae (Figs 76–77); empodium with a pair of lanceolate empodial setae (Figs 76–77, emps).
Elytra (Figs 5–6) oval, flattened, lacking humeral calli and basal impressions, with rounded apices; elytral disc with distinct small, moderately deep or shallow and dense punctures arranged in indistinct rows, in some species barely discernible.
Hind wings absent.
Abdomen (Figs 66, 71, 74) with sternite III not fused with metaventrite, about as long as sternites IV and V together or slightly longer. Sternite III with indistinct and shallow anterolateral (postmetacoxal) impressions filled with short leaf-like setae.
Aedeagus (illustrated in Jałoszyński et al. (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 relatively short and narrow sperm pump, its both ends with broad sclerotized funnel-like structures.
Spermatheca (Fig. 71; sp) thin-walled, strongly elongate, recurved.
Larva. Unknown.
Composition and distribution. Only three nominal species are known, inhabiting the south-central and southeastern part of Turkey (Fig. 9).
Natural history. Species of Taurablepton were collected from leaf litter accumulated along a stream in a pine forest (Franz 1988), in leaf litter in a deep gorge (Besuchet 1969) and in soil under a partially rotten oak (Besuchet 1969). Nothing else is known about life of this enigmatic genus.
Remarks. Morphological structures of Taurablepton and Ablepton are very similar, but these genera can be easily distinguished at first sight on the basis of a clearly different shape of the head (subtriangular in Taurablepton and subquadrate with rounded tempora in Ablepton). Other differences include: the sides of clypeus (in Taurablepton not forming rounded lobes projecting anterolaterad vs. with such lobes in Ablepton); the postgenae (in Taurablepton lacking longitudinal ridges vs. with distinct ridges in Ablepton); the median projections of anterior and posterior margins of setose impression of mesoventrite (nearly touching each other in Taurablepton vs. broadly separated in Ablepton); the postmesocoxal foveae (directed anteromesad in Taurablepton vs. mesad in Ablepton); the mesoscutellum (subtrapezoidal with truncated tip in Taurablepton vs. subtriangular and pointed in Ablepton); the median longitudinal carina of metaventrite (absent in Taurablepton vs. present in Ablepton). Possible differences are also the shape of spermatheca (strongly elongate in Taurablepton vs. globular in Ablepton) and basal rings of antennomeres III–XI (serrate in Taurablepton vs. smooth in Ablepton), but these characters were not studied in all species of Taurablepton and may be variable with this genus. Taurablepton shows a tendency toward reducing the rows of punctures on elytra; in some species they are relatively distinct, although less regular than those in Ablepton treforti and most species of Leptomastax, but in some the rows are indistinct, irregular, incomplete or even barely discernible.
The holotype of Taurablepton subterraneum Franz, 1988, the type species of the genus, was not found in the Franz Collection neither by myself nor by the NHMW curators (H. Schillhammer, pers. comm.), but the shape of head described by Franz (1988) agrees with that in the two nominal and several undescribed species from the same area examined during the present study.
Many males and females, possibly representing several species, are preserved in the collection of Heinrich Meybohm, all collected in Turkey. They include also specimens collected in the type localities of the nominal species. However, males that differ considerably in body length and proportions of body parts have nearly identical aedeagi; differences are rather subtle, and on the basis of external characters it is difficult to assign specimens to 'morphospecies', because shapes and measurements seem to change gradually. It is either one or two highly variable species, or a complex of populations that has only recently started differentiating. A larger sample of specimens and molecular methods used along with morphological analysis should be used to clarify this problem.
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 31-38, DOI: 10.11646/zootaxa.4453.1.1, http://zenodo.org/record/1454920