Euconnus claviger (Müller & Kunze), Muller & Kunze

Jałoszyński, Paweł, 2015, Taxonomy of ' Euconnus complex'. Part III. Morphology of Euconnus subgenus Napochus and revision of the Australian species (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 3925 (1), pp. 1-24 : 3-10

publication ID	https://doi.org/ 10.11646/zootaxa.3925.1.1
publication LSID	lsid:zoobank.org:pub:780FE466-6667-416A-93ED-2E1C1A179CFE
persistent identifier	https://treatment.plazi.org/id/D76587E0-7870-FFEF-C693-F9E8FB642FFF
treatment provided by	Plazi
scientific name	Euconnus claviger (Müller & Kunze)
status

Treatment

Morphology of Euconnus claviger (Müller & Kunze) , the type species of Euconnus (Napochus)

General body shape ( Figs. 1–2 View FIGURES 1 – 2 ) elongate, body distinctly constricted between head and pronotum but very weakly so between pronotum and elytra, strongly convex but with slightly flattened dorsum; appendages long and slender, vestiture of setae sparse, long and suberect, in addition to thin setae thick bristles are present on various body parts.

Head capsule ( Figs. 1–2 View FIGURES 1 – 2 , 3–6 View FIGURES 3 – 6 ) divided by occipital constriction into large anterior and small posterior part ('neck region'), the posterior part retracted into pronotum. Neck region much narrower than anterior part of head, short and not broadening towards foramen occipitale ( Fig. 5 View FIGURES 3 – 6 ; fo); the narrowest place of occipital constriction about as wide as half HW. Anterior part of head ( Figs. 3, 5 View FIGURES 3 – 6 ) approximately rhomboidal, broadest at eyes and narrowing both anteriorly and posteriorly. Dorsum of head ( Fig. 3 View FIGURES 3 – 6 ) convex; tempora about as long as compound eyes; vertex ( Fig. 3 View FIGURES 3 – 6 ; vt) transverse and nearly evenly convex, anteriorly confluent with subtrapezoidal and convex frons ( Fig. 3 View FIGURES 3 – 6 ; fr), which is steeply declining anteriorly; supraantennal tubercles barely raised; genae elongate, weakly convex. Clypeus ( Figs. 3–4 View FIGURES 3 – 6 ; cp) demarcated from frons by indistinct transverse frontoclypeal groove ( Fig. 5 View FIGURES 3 – 6 ; fcg), anterior margin of clypeus slightly concave and its anterolateral corners forming subtriangular teeth projecting anteriorly. Vestiture of head capsule composed mostly of thick bristles sparse on median part of vertex and frons and dense on genae, tempora, sides and posterior margin of vertex. Ventral side of head ( Fig. 5 View FIGURES 3 – 6 ) flattened; gular plate ( Fig. 5 View FIGURES 3 – 6 ; gp) in posterior part with indistinctly marked gular sutures ( Fig. 5 View FIGURES 3 – 6 ; gs), anterior part adjacent to posterior tentorial pits ( Fig. 5 View FIGURES 3 – 6 ; ptp) without sutures and indistinctly separated from submentum ( Fig. 5 View FIGURES 3 – 6 ; smn); posterior tentorial pits ( Fig. 5 View FIGURES 3 – 6 ; ptp) elongate and located anteriorly to transverse groove separating 'neck region' from anterior part of head.

Mouthparts ( Figs. 3–6 View FIGURES 3 – 6 ). Labrum ( Figs. 3–4 View FIGURES 3 – 6 ; lb) transverse, with rounded and anteriorly convergent sides and slightly emarginate anterior margin, dorsal surface with one transverse row of long setae located behind middle and a pair of anterolateral setae. Epipharynx (ventral surface of labrum) with six nearly straight peg-like median marginal sensilla ( Fig. 4 View FIGURES 3 – 6 ; mse) directed anteromesally. Mandibles ( Figs. 3–4 View FIGURES 3 – 6 ; md) symmetrical, moderately large, nearly planar and thin, subtriangular with broad base gradually narrowing distally into slender and strongly curved apical tooth, without subapical mesal teeth; prostheca rudimentary, composed of numerous dense and short trichia occupying narrow and short sub-basal mesal area. Maxilla ( Figs. 4, 5–6 View FIGURES 3 – 6 ) elongate, with transverse cardo ( Fig. 6 View FIGURES 3 – 6 ; cd); subtriangular and elongated basistipes ( Fig. 6 View FIGURES 3 – 6 ; bst); elongate and broad mediostipes ( Fig. 11 View FIGURES 11 – 13 ; mst); galea ( Figs. 4, 6 View FIGURES 3 – 6 ; gal) short, with long and dense trichia along distal margin; lacinia elongate, with long and dense trichia along distal and mesal margin; maxillary palp ( Fig. 5 View FIGURES 3 – 6 ; mxp) long, palpomere I small, about as long as broad, palpomere II strongly elongate and slightly thickening distally, pipe-like, palpomere III longer than I and strongly broadening distally, broadest near distal third; palpomere IV minute, subconical and slender, with elongate and pointed apical part. Labium ( Figs. 5–6 View FIGURES 3 – 6 ) with transverse submentum ( Figs. 5–6 View FIGURES 3 – 6 ; smn) laterally not demarcated from hypostome; mentum ( Figs. 5–6 View FIGURES 3 – 6 ; mn) subquadrate; prementum short, with indistinctly demarcated ligula ( Fig. 6 View FIGURES 3 – 6 ; lig) bearing pair of moderately long median setae; labial palps ( Fig. 6 View FIGURES 3 – 6 ; lp) shorter than mentum, palpomere I slightly transverse, palpomere II strongly elongate and broadening distally, palpomere III long and slender, narrowing distally. Posteriorly and laterally mouthparts demarcated by hypostomal ridges ( Fig. 6 View FIGURES 3 – 6 ; hr) which are strongly curved mesally and in posterior half nearly parallel.

Antennae ( Figs. 1–2 View FIGURES 1 – 2 ) slender, scape and pedicel elongate, antennomeres III–VI compactly assembled and nearly cylindrical, not narrowing proximally or distally; antennomeres VII–XI forming sharply delimited and loosely assembled club, antennomeres VII–X distinctly narrowing both proximally and distally, antennomere XI only slightly longer than broad. All antennomeres covered with sparse long setae.

Prothorax ( Figs. 1–2 View FIGURES 1 – 2 , 7–9 View FIGURES 7 – 10 ) strongly convex but with distinctly flattened pronotal dorsum, broadest at base, in dorsal view ( Figs. 1 View FIGURES 1 – 2 , 7 View FIGURES 7 – 10 ) elongate subtrapezoidal, with nearly straight anterior margin; lateral margins weakly rounded and strongly convergent anteriorly, with indistinct constriction in anterior 1/5; posterior margin expanded posteriorly at middle. Pronotum without lateral carinae or sharp edges but with short, low and slightly irregular sublateral carinae ( Figs. 15 View FIGURES 14 – 17 , 7–8 View FIGURES 7 – 10 ; slc); anterior and posterior corners of pronotum blunt but well-defined, anterior obtuse and posterior nearly right-angled. Base of pronotum ( Figs. 7–8 View FIGURES 7 – 10 ) with pair of very small and deep lateral antebasal pits ( Figs. 7–8 View FIGURES 7 – 10 ; lap) connected by indistinct, shallow transverse impression. Dorsal and dorsolateral surface of pronotum covered with long and erect bristles and thin setae concealed by bristles. Prosternum ( Fig. 9 View FIGURES 7 – 10 ) nearly 3 times shorter than pronotum, with basisternal part ( Fig. 9 View FIGURES 7 – 10 ; bst) rudimentary and not demarcated from procoxal cavities ( Fig. 9 View FIGURES 7 – 10 ; pcc) by carina; prosternal intercoxal process ( Fig. 9 View FIGURES 7 – 10 ; psp) present, carinate but weakly expanding ventrally and in intact specimens concealed between procoxae; procoxal sockets ( Fig. 9 View FIGURES 7 – 10 ; pcs) closed by broad posterolateral expansions of prosternum; profurcal (postcoxal) foveae ( Fig. 9 View FIGURES 7 – 10 ; pff) large and distinct. Hypomera ( Fig. 9 View FIGURES 7 – 10 ; hy) elongate, with nearly straight internal (mesal) margins, divided by entire hypomeral ridges ( Fig. 9 View FIGURES 7 – 10 ; hyr) into small subtriangular internal (adcoxal) part and large external part confluent laterally with sides of pronotum; pronotosternal sutures ( Fig. 9 View FIGURES 7 – 10 ; nss) entire and nearly straight.

Mesothorax ( Figs. 10–12 View FIGURES 7 – 10 View FIGURES 11 – 13 , 16–17 View FIGURES 14 – 17 ). Mesonotum ( Fig. 10 View FIGURES 7 – 10 ) subtriangular in shape; mesoscutum ( Fig. 10 View FIGURES 7 – 10 ; sc2) strongly transverse, with two groups of several thick lateral bristles; scutoscutellar suture ( Fig. 10 View FIGURES 7 – 10 ; sss) wellmarked on the surface as transverse ridge; mesoscutellum ( Fig. 10 View FIGURES 7 – 10 ; scl2) not visible between bases of elytra in intact specimens, triangular with rounded posterior margin.

Mesoventrite ( Figs. 11–12 View FIGURES 11 – 13 , 16–17 View FIGURES 14 – 17 ) relatively short, much broader than long, with rudimentary anterior ridge ( Fig. 12 View FIGURES 11 – 13 ; ar); behind anterior ridge with lateral pair of strongly transverse impressions functioning as procoxal rests ( Figs. 11–12 View FIGURES 11 – 13 ; pcr) with setose posterior margins; mesoventral intercoxal process ( Figs. 11–12 View FIGURES 11 – 13 , 16 View FIGURES 14 – 17 ; msvp) slender and keel-like, strongly projecting ventrally, covered with polygonal microsculpture ( Fig. 17 View FIGURES 14 – 17 ); mesocoxal sockets ( Fig. 12 View FIGURES 11 – 13 ; mscs) located lateromesally on mesocoxal projections ( Fig. 12 View FIGURES 11 – 13 ; mcp); mesofurcal foveae ( Fig. 12 View FIGURES 11 – 13 ; msff) large and located submedially in mesocoxal cavities ( Fig. 12 View FIGURES 11 – 13 ; mscc), which are asetose. Prepectus ( Fig. 12 View FIGURES 11 – 13 ; pre) short, posterior part of mesanepisternum ( Fig.16 View FIGURES 14 – 17 ; aest2) only partly visible in ventral view, with setae distributed along its posterodorsal margin which is fused with asetose mesepimeron ( Fig. 16 View FIGURES 14 – 17 ; epm2) and with metanepisternum ( Fig. 16 View FIGURES 14 – 17 ; aest3). Mesothorax with dorsolateral foveae ( Fig. 16 View FIGURES 14 – 17 ; dlf) only; ventrolateral foveae absent.

Metathorax ( Figs. 11, 13–16 View FIGURES 11 – 13 View FIGURES 14 – 17 ). Premetascutum ( Figs. 14–15 View FIGURES 14 – 17 ; prsc3) large, transverse; metascutum ( Figs. 14–15 View FIGURES 14 – 17 ; sc3) very large and transverse, with robust oblique lateral apodemes ( Fig. 15 View FIGURES 14 – 17 ; apo) on ventral side, in middle with broad and impressed median membranous area ( Figs. 14–15 View FIGURES 14 – 17 ; mma); alacristae ( Fig. 14 View FIGURES 14 – 17 ; alc) nearly as long as scutum; metascutellum ( Figs. 14–15 View FIGURES 14 – 17 ; scl3) rudimentary; postmetanotum ( Figs. 14–15 View FIGURES 14 – 17 ; psn3) large, strongly transverse.

Metaventrite ( Figs. 11, 13 View FIGURES 11 – 13 , 16 View FIGURES 14 – 17 ; v3) much longer than mesoventrite, subquadrate in shape, anteriorly fused with mesoventrite, lateral margins slightly rounded, lateral (admetacoxal) parts of posterior margin weakly concave, in middle posterior margin expanded posteriorly and forming subtrapezoidal metaventral intercoxal process ( Fig. 13 View FIGURES 11 – 13 ; mtvp) with slightly concave posteromedian margin. Metanepisterna ( Fig. 16 View FIGURES 14 – 17 ; aest3) not visible in ventral view, strongly elongate but anteriorly relatively broad, strongly narrowing posteriorly; metepimera ( Figs. 11 View FIGURES 11 – 13 , 16 View FIGURES 14 – 17 ; epm3) in ventral view visible posteriorly, elongate, slightly broadening posteriorly.

Metafurca (metendosternite) ( Fig. 18 View FIGURES 18 – 23 ) with short stem ( Fig. 18 View FIGURES 18 – 23 ; mtfs) and strongly divergent lateral furcal arms ( Fig. 18 View FIGURES 18 – 23 ; lmfa).

Elytra ( Figs. 1–2 View FIGURES 1 – 2 , 19 View FIGURES 18 – 23 ) oval, with rounded apices; humeral denticle absent; humeral callus moderately distinct, delimited from adsutural region by shallow basal impression; subhumeral line absent; elytral base with two distinct, circular and asetose basal foveae ( Fig. 19 View FIGURES 18 – 23 ; bef); elytral disc sparsely covered with long, curved and suberect setae.

Metathoracic wings about twice as long as elytra, with posterior margin bearing dense fringe of long setae; venation highly reduced and with few indistinct veins visible only in basal part of wing, homology difficult to interpret.

Abdomen ( Figs. 20–22 View FIGURES 18 – 23 ) elongate; abdominal sternites III–VIII ( Fig. 20 View FIGURES 18 – 23 ; st3–8) gradually narrowing towards abdominal apex, sternite III longest, with shallow metacoxal cavities ( Fig. 20 View FIGURES 18 – 23 ; mtcc) each demarcated posteriorly by curved coxal line ( Fig. 20 View FIGURES 18 – 23 ; cxl); suture between sternite VII and VIII ( Fig. 20 View FIGURES 18 – 23 ) less distinct than between remaining sternites. Propygidium ( Fig. 21 View FIGURES 18 – 23 ; prpg) hidden under elytra, strongly sclerotized and densely covered with transverse rows of trichia ( Fig. 22 View FIGURES 18 – 23 ); pygidium ( Fig. 21 View FIGURES 18 – 23 ; pg) exposed in intact specimens, strongly sclerotized, subtriangular with rounded apex, covered with scale-like microsculpture, each 'scale' ( Fig. 22 View FIGURES 18 – 23 ; s) with posterior row of short trichia, between 'scales' sparsely distributed convex porous fields ( Fig. 22 View FIGURES 18 – 23 ; pf).

Aedeagus ( Fig. 23 View FIGURES 18 – 23 ) symmetrical, elongate but relatively stout, with broad and bulbous median lobe and abruptly demarcated apical projections continuous with dorsal and ventral aedeagal walls; ostium concealed between apical projections; basal foramen ( Fig. 23 View FIGURES 18 – 23 ; bo) located in sub-basal region of dorsal aedeagal wall; ventral apical projection ( Fig. 23 View FIGURES 18 – 23 ; vap) short, plate-like, with subtrapezoidal apical portion; dorsal apical projection ( Fig. 23 View FIGURES 18 – 23 ; dap) long, with subtrapezoidal apex. Parameres ( Fig. 23 View FIGURES 18 – 23 ; pm) free (i.e., not fused with median lobe), broad, each with two approximate apical setae. Internal armature of aedeagus in transparent mounts ( Fig. 23 View FIGURES 18 – 23 ) visible as darkly sclerotized complex of sclerites, containing pair of hook-like internal lateral projections ( Fig. 23 View FIGURES 18 – 23 ; ilp) in repose partly protruding from ostium at each side of ventral apical projection.

Remarks. Several structures, previously described in detail for Euconnus s. str. ( Jałoszyński 2012a), were omitted from illustrations and descriptions presented here. The reason was the small number of specimens available for dissections, and therefore some structures remained hidden when others were exposed and documented by SEM, and some others were partly damaged during disarticulations. However, some of such structures, even if not possible to visualize in photographs suitable for publication, were examined, and the female ovipositor, spermatheca, and male terminalia were found to be similar (i.e., not substantially different in general structure) to those of Euconnus s. str.

Examination of the Australian species revealed that there are two pairs of lateral projections of the endophallus. The internal pair is always more distinct in the specimens studied, usually also larger and darker than the external lateral projections. The latter are lightly pigmented and may be obscured by the internal pair or are indiscernible in all or some specimens. In Euconnus claviger only one pair of lateral projections was found, and they are dark and distinct ( Fig. 23 View FIGURES 18 – 23 ). Therefore, they are here interpreted as internal lateral projections and the external pair in the type species of Napochus may be concealed by large internal projections, being indiscernible in transparent preparations or are missing. Aedeagi of the Australian species show distinct similarities in structure to the copulatory organ of E. claviger ; they all have flattened ventral and dorsal apical projections, lateral projections, and symmetrical dark median components of endophallus. The slightly asymmetrical median component of the endophallus visible in the studied specimen of E. claviger ( Fig. 23 View FIGURES 18 – 23 ) seems to be dislocated. In many specimens studied at various times by me this structure was found to be quite variable and prone to distortion.