Euconnus hirticollis Illiger
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scydmaenidae
Euconnus
Euconnus hirticollis

description: Morphology of Euconnus hirticollis (Illiger), the type species of Euconnus Thomson
General body shape (Figs. 1–2) elongate, moderately slender; body distinctly constricted between head and pronotum but weakly between pronotum and elytra, strongly convex; appendages long and slender, vestiture distinct and not uniform, i.e., various body parts distinctly differ in thickness, length and density of setae.
Head capsule (Figs. 3–6) divided by occipital constriction (Figs. 3–4; occ) into large anterior and small posterior part ('neck region'), the posterior part retracted into pronotum. Neck region (Figs. 3–4; nr) broadening towards foramen occipitale (Fig. 4; fo); narrowest site of occipital constriction about as wide as half HW. Anterior part of head (Figs. 3–4) nearly hemispherical. Dorsum of head (Fig. 3) strongly convex; tempora (Fig. 3; tm) in dorsal view slightly longer than compound eyes (Fig. 3; ce); vertex (Fig. 3; vt) transverse and nearly evenly convex, anteriorly confluent with subrapezoidal and convex frons (Fig. 3; fr), which is steeply declining anteriorly; supraantennal tubercles feebly developed; genae (Figs. 3–4, 6; gen) elongate, convex. Clypeus (Fig. 5; cp) separated from frons and genae by distinct transverse fronto-clypeal groove (Fig. 5; fcg). Vestiture of head dorsum sparse and composed of long suberect to erect setae, with loose groups on tempora and genae, but without thick bristles. Ventral side of head (Fig. 6) flattened; gular plate (Fig. 6; gp) in posterior part with indistinct gular sutures (Fig. 6; gs), in anterior part with lateral ridges, gular plate indistinctly separated from submentum (Fig. 6; smn); posterior tentorial pits (Fig. 6; ptp) elongate and located on anterior part of gular plate.
Mouthparts (Figs. 6–14). Labrum (Fig. 7; lb) transverse, with rounded sides and nearly straight anterior margin, dorsal surface with three rows of long setae. Epipharynx (ventral surface of labrum) (Fig. 8; eph) with six curved peg-like median marginal sensilla (Fig. 8; mse) directed anterad and dense lateral groups of trichia (Fig. 8; lte) directed mesad. Mandibles (Figs. 7, 9–10; md) symmetrical, moderately large, nearly planar, subtriangular with broad base narrowing distally into slender and strongly curved apical tooth (Fig. 7; at), with small and sharp subapical mesal tooth (Fig. 7; sat); prostheca (Figs. 7, 9–10; pst) composed of numerous dense and short trichia expanded onto dorsal surface of mandible and occupying nearly half of mandibular base. Maxillae (Figs. 11–12, 14) elongate, with oblique cardo (Fig. 11; cd) bearing long submedian and short basal seta; basistipes (Fig. 11; bst) subtriangular, with two long subbasal setae; mediostipes (Fig. 11; mst) elongate and connected to lacinia; galea (Figs. 11–12; gal) short, with long and dense trichia along distal margin and long seta on external margin; lacinia (Figs. 11–12; lac) elongate, with long and dense trichia along distal and mesal margin; maxillary palps (Fig. 12) long, palpomere I (Fig. 12; mxpI) small, about 2.5× as long as broad, palpomere II (Fig. 12; mxpII) strongly elongate and slightly thickening distally, with several long setae, palpomere III (Fig. 12; mxpIII) longer than I and strongly broadening distally, broadest near distal third, covered with sparse and long setae; palpomere IV (Fig. 12; mxpIV) minute, subconical, with elongate and pointed apical part, with dense and moderately long setae near base and asetose in distal half. Labium (Figs. 13–14) with transverse submentum (Fig. 14; smn) laterally fused to hypostoma (Fig. 14; h) and bearing a pair of long latero-anterior setae; mentum (Fig. 14; mn) subtrapezoidal with two pairs of short latero-anterior setae; prementum short, with a pair of moderately long median setae (Fig. 13; ms); labial palps shorter than mentum, palpomere I (Fig. 14; lpI) only slightly longer than wide, asetose, palpomere II (Fig. 14; lpII) strongly elongate and slightly broadening distally, with several submedian and subapical setae, palpomere III (Fig. 14; lpIII) long and slender, asetose. Hypopharynx (dorsal surface of labium) (Fig. 13) with elongate lateral lobes (Fig. 13; llh) densely covered with trichia (Fig. 13; tr) and exceeding length of prementum, median part covered densely with trichia. Posteriorly and laterally mouthparts demarcated by hypostomal ridges (Fig. 14; hr) strongly convergent caudad; hypostoma (Fig. 14; h) anteriorly narrow and elongate, posteriorly fused with submentum.
Antennae (Figs. 1–2) slender, gradually thickening towards apices, antennomeres compactly assembled in proximal part and loosely in distal part, sparsely covered with suberect to erect setae.
Prothorax (Figs. 15–18) strongly convex, in dorsal view (Fig. 15) elongate subtrapezoidal, with rounded anterior and lateral margins and posterior margin distinctly expanded caudad in middle, without lateral carinae or sharp edges but with short and rounded sublateral carina (Figs. 15, 17–18; slc); anterior and posterior corners of pronotum blunt but well-defined. Pronotum (Figs. 15, 17; pn) with two small and shallow sublateral basal foveae (Figs. 15, 17–18; bf), entire surface covered with long and erect bristles, much thicker than those on remaining body parts except sides of mesothorax. Prosternum (Fig. 16; ps) about 3 times shorter than pronotum, with basisternal part short and not delimited from procoxal cavities (Fig. 16; pcc); prosternal intercoxal process or carina absent, procoxae contiguous; procoxal sockets (Fig. 16; pcs) closed by lateral expansions of prosternum; profurcal (postcoxal) foveae (Fig. 16; pff) relatively large. Hypomera (Fig. 16; hy) subtriangular, elongate, not expanded mesally, with nearly straight internal (mesal) margins, each delimited from pronotum on entire length by hypomeral ridge (Fig. 16; hr) and from sternum by straight and entire notosternal suture (Fig. 16; nss); profurcal arms (Fig. 16; pf) tubular, with expanded apices.
Mesothorax (Figs. 19–27). Mesonotum (Fig. 19) subtriangular in shape; mesoscutum (Fig. 19; sc II) strongly transverse, asetose; scuto-scutellar suture (Fig. 19; sss) barely marked on the surface; mesoscutellum (Fig. 19; scl II) well visible between bases of elytra in intact specimens, triangular with rounded posterior margin, covered with scale-like sculpture and bearing lateral groups of five thick setae (partly broken off in specimen shown in Fig. 19; ls); posterior and anterior notal processes (Fig. 19; pnp, anp) prominent.
Mesoventrite (Figs. 20–22, 25, 27) relatively short, much broader than long, with broad anterior ridge (Fig. 21; ar) bearing large and subtriangular median projection (Fig. 21; par) connected with long, slender and keel-like mesoventral intercoxal process (Fig. 21; msvp) strongly projecting ventrad (Figs. 20, 27); mesoventrite behind anterior ridge with lateral pair of subtriangular setose impressions (Fig. 21; se) separated from mesocoxal cavities (Fig. 21; mscc) by oblique ridge (Fig. 21; or); mesocoxal sockets (Fig. 21; mscs) located laterally; mesofurcal foveae (Figs. 21-22; msff) large and located submedially on lateral parts of mesocoxal cavities, which are largely asetose. Prepectus (Fig. 21; pre) relatively long, posterior part of mesanepisternum (Fig.21; aestII) partly visible in ventral view, densely covered with thick and suberect to erect bristles; latero-ventral margins of mesepimera (Fig. 27; epmII) obscured by dense bristles, possibly mesepimera fused (partly or entirely) with large mesanepisterna (Fig. 27; aestII) and entirely fused with metanepisterna (Fig. 27; aestIII). Mesothorax with two pairs of deep lateral foveae (Figs. 22, 26-27): ventro-lateral fovea (Figs. 22, 27; vlf) located latero-ventrally between prepectus and setose part of mesanepisternum and dorso-lateral fovea (Figs. 22, 27; dlf) located latero-dorsally between mesepimeron + mesanepisternum and metanepisternum (aestIII); internally (Fig. 26) walls of dorso-lateral fovea (Fig. 26; dlf) forming a tubular structure connected to basal part of thick mesofurcal arm (Fig. 26; msff) and together constituting latero-ventral internal scaffold of mesothorax.
Metathorax (Figs. 23–27). Premetascutum (Figs. 23–24; prsc III) large, transverse; metascutum (Figs. 23–24; sc III) very large and transverse, with robust oblique lateral apodemes (Fig. 24; ap) on ventral side, in middle with broad and impressed median membranous area (Figs. 23–24; mma); alacristae (Figs. 23–24; alc) nearly as long as scutum; metascutellum (Fig. 23; scl III) rudimentary, metascuto-scutellar suture indiscernible; metapostnotum (Figs. 23–24; psn III) large, strongly transverse.
Metaventrite (Figs. 25–27; vIII) much longer than mesoventrite, subquadrate in shape, anteriorly fused with mesoventrite, lateral margins slightly rounded, lateral (admetacoxal) parts of posterior margin nearly straight, in middle posterior margin expanded caudad and forming broad and subtrapezoidal metaventral intercoxal process (Fig. 25; mtvp); median part of ventrite covered with long setae, in anterior part with sparse and thick bristles.
Metanepisterna (Figs. 25–27; aestIII) partly visible in ventral view, strongly elongate but relatively broad, slightly narrowing caudad; metepimera (Figs. 25–27; epmIII) elongate, distinctly broadening caudad; anapleural cleft (Figs. 25, 27; apc) distinct and nearly entire, with only short anterior part obliterated.
Metafurca (metendosternite) (Fig. 26) with short stem (Fig. 26; mfs) and strongly divergent lateral furcal arms (Fig. 26; lmfa).
Elytra (Figs. 1, 23, 28) oval, with rounded apices; humeral denticle absent; humeral callus moderately distinct, indistinctly delimited from adsutural region by shallow basal impression; subhumeral line absent; elytral base with two distinct, circular and asetose basal foveae (Fig. 23; bef); elytral disc sparsely covered with long, curved and suberect setae. Ventral surface of elytron (Fig. 28) with elongate sutural trichial pad (Fig. 28; stp) on basal part of sutural rim; oval sublateral trichial pad (sltp) in subbasal region and irregular setal row along lateral subapical (Fig. 28; lsr) and apical (Fig. 28; sasr) elytral margin.
Metathoracic wings (Fig. 29) about twice as long as elytra, with posterior margin bearing dense fringe of long setae; venation highly reduced and homology of few indistinct veins visible only in basal part of wing difficult to interpret.
Abdomen (Figs. 30–33) elongate, subtriangular; abdominal sternites III–VIII (Fig. 30; stIII–VIII) gradually narrowing towards abdominal apex, sternite III longest, with shallow metacoxal cavities (Fig. 30; mtcc) each demarcated posteriorly by curved coxal line (Fig. 30; cxl); suture between sternite VII and VIII (Fig. 31) less distinct than between remaining sternites. Propygidium (Fig. 32; prpg) hidden under elytra, strongly sclerotized and densely covered with transverse rows of trichia (Fig. 33); pygidium (Fig. 32; pg) exposed in intact specimens, strongly sclerotized, subtriangular with rounded apex, covered with setae.
Female terminalia (Figs. 30, 34). Ovipositor lightly sclerotized and fragile; proctiger (Fig. 34; prc) subtriangular with rounded posterior margin, separated from fused and large paraprocts (Fig. 34; ppr); valvifers (Fig. 34; vf) large, distal margin of each with row of setae; coxites fused indistinguishably to valvifers; styli absent.
Spermatheca (Figs. 35–36) very small, ovoid, thick-walled, in axial view asymmetrically oval, in lateral view flattened and slightly irregular, basal part of ductus spermathecae (Fig. 36; ds) thick; accessory gland not found.
Male terminalia (Figs. 37–39). Sternite IX (Figs. 37–38) large, with arcuate anterior (proximal) margin, lateral margins nearly straight in proximal half and only slightly convergent caudad in posterior half, posterior (distal) margin slightly emarginate; tergite IX (Figs. 37–38) reduced to lateral apodemes (Figs. 37–38; ap tIX) fused with latero-distal margins of sternite IX; tergite X (Fig. 39) subtriangular with rounded apical margin.
Aedeagus (Figs. 40–45) bulbous, elongate but relatively stout, with rounded base of median lobe and narrowing apically, with lightly sclerotized membranous area (Fig. 41; ma) on ventral wall (Fig. 40; vw), strongly sclerotized subtriangular ventral apical projection (Figs. 40–41; vap) distal to membranous area and distinctly separated from strongly sclerotized parts of ventral wall, and subtrapezoidal dorsal apical projection (Figs. 41, 43; dap) continuous with dorsal wall (Fig. 43; dw). Dorsal wall of median lobe bearing lateral groups of minute setae or trichia with impressed bases (Fig. 44). Parameres (Figs. 40–44; pm) free (i.e., not fused with median lobe), slender, each with two approximate apical setae (Fig. 42) and group of 3–4 short and thin subapical setae (Fig. 42). Basal orifice (Fig. 43; bo) large, located subbasally on dorsal wall. Internal armature of aedeagus in transparent mounts (Fig. 40; ia) visible as elongate, paired and darkly sclerotized structure with several unclearly demarcated subcomponents; isolated internal armature in dorsal view (Fig. 45) is a complex structure composed of central sclerite accompanied at each side by elongate columns connected at base and at apices, with U-shaped median apical subcomponent; base (i.e., proximal part) of internal armature connected with internal surface of dorsal wall, this connection does not seem permanent and in some studied aedeagi the sclerotized internal armature was displaced, usually shifted towards the base of median lobe or slightly rotated.
description: Published as part of Jałoszyński, Paweł, 2012, Taxonomy of ' Euconnus complex'. Part I. Morphology of Euconnus s. str. and revision of Euconnomorphus Franz and Venezolanoconnus Franz (Coleoptera: Staphylinidae: Scydmaeninae), pp. 55-82 in Zootaxa 3555 on pages 57-67, DOI: 10.5281/zenodo.282872