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

General body shape (Figs. 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, 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; fo); the narrowest place of occipital constriction about as wide as half HW. Anterior part of head (Figs. 3, 5) approximately rhomboidal, broadest at eyes and narrowing both anteriorly and posteriorly. Dorsum of head (Fig. 3) convex; tempora about as long as compound eyes; vertex (Fig. 3; vt) transverse and nearly evenly convex, anteriorly confluent with subtrapezoidal and convex frons (Fig. 3; fr), which is steeply declining anteriorly; supraantennal tubercles barely raised; genae elongate, weakly convex. Clypeus (Figs. 3–4; cp) demarcated from frons by indistinct transverse frontoclypeal groove (Fig. 5; 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) flattened; gular plate (Fig. 5; gp) in posterior part with indistinctly marked gular sutures (Fig. 5; gs), anterior part adjacent to posterior tentorial pits (Fig. 5; ptp) without sutures and indistinctly separated from submentum (Fig. 5; smn); posterior tentorial pits (Fig. 5; ptp) elongate and located anteriorly to transverse groove separating 'neck region' from anterior part of head.

Mouthparts (Figs. 3–6). Labrum (Figs. 3–4; 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; mse) directed anteromesally. Mandibles (Figs. 3–4; 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) elongate, with transverse cardo (Fig. 6; cd); subtriangular and elongated basistipes (Fig. 6; bst); elongate and broad mediostipes (Fig. 11; mst); galea (Figs. 4, 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; 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) with transverse submentum (Figs. 5–6; smn) laterally not demarcated from hypostome; mentum (Figs. 5–6; mn) subquadrate; prementum short, with indistinctly demarcated ligula (Fig. 6; lig) bearing pair of moderately long median setae; labial palps (Fig. 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; hr) which are strongly curved mesally and in posterior half nearly parallel.

Antennae (Figs. 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, 7–9) strongly convex but with distinctly flattened pronotal dorsum, broadest at base, in dorsal view (Figs. 1, 7) 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, 7–8; slc); anterior and posterior corners of pronotum blunt but well-defined, anterior obtuse and posterior nearly right-angled. Base of pronotum (Figs. 7–8) with pair of very small and deep lateral antebasal pits (Figs. 7–8; 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) nearly 3 times shorter than pronotum, with basisternal part (Fig. 9; bst) rudimentary and not demarcated from procoxal cavities (Fig. 9; pcc) by carina; prosternal intercoxal process (Fig. 9; psp) present, carinate but weakly expanding ventrally and in intact specimens concealed between procoxae; procoxal sockets (Fig. 9; pcs) closed by broad posterolateral expansions of prosternum; profurcal (postcoxal) foveae (Fig. 9; pff) large and distinct. Hypomera (Fig. 9; hy) elongate, with nearly straight internal (mesal) margins, divided by entire hypomeral ridges (Fig. 9; hyr) into small subtriangular internal (adcoxal) part and large external part confluent laterally with sides of pronotum; pronotosternal sutures (Fig. 9; nss) entire and nearly straight.

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

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

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

Metaventrite (Figs. 11, 13, 16; 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; mtvp) with slightly concave posteromedian margin. Metanepisterna (Fig. 16; aest3) not visible in ventral view, strongly elongate but anteriorly relatively broad, strongly narrowing posteriorly; metepimera (Figs. 11, 16; epm3) in ventral view visible posteriorly, elongate, slightly broadening posteriorly.

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

Elytra (Figs. 1–2, 19) 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; 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) elongate; abdominal sternites III–VIII (Fig. 20; st3–8) gradually narrowing towards abdominal apex, sternite III longest, with shallow metacoxal cavities (Fig. 20; mtcc) each demarcated posteriorly by curved coxal line (Fig. 20; cxl); suture between sternite VII and VIII (Fig. 20) less distinct than between remaining sternites. Propygidium (Fig. 21; prpg) hidden under elytra, strongly sclerotized and densely covered with transverse rows of trichia (Fig. 22); pygidium (Fig. 21; pg) exposed in intact specimens, strongly sclerotized, subtriangular with rounded apex, covered with scale-like microsculpture, each 'scale' (Fig. 22; s) with posterior row of short trichia, between 'scales' sparsely distributed convex porous fields (Fig. 22; pf).

Aedeagus (Fig. 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; bo) located in sub-basal region of dorsal aedeagal wall; ventral apical projection (Fig. 23; vap) short, plate-like, with subtrapezoidal apical portion; dorsal apical projection (Fig. 23; dap) long, with subtrapezoidal apex. Parameres (Fig. 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) visible as darkly sclerotized complex of sclerites, containing pair of hook-like internal lateral projections (Fig. 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). 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) 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.