Euconnus (Cladoconnus)

Jałoszyński, Paweł, 2018, Taxonomy of ' Euconnus complex'. Part XVII. Status of subgenera defined by male antennal characters: Androconnus Franz and Cladoconnus Reitter (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 4415 (2), pp. 369-380 : 374-377

2. Morphological structures of Euconnus (Cladoconnus)

The general body shape of Euconnus motschulskyi ( Fig. 2 ) and other members of Cladoconnus is similar to that of many species of Euconnus , including those of Androconnus ; it is slender or stout, moderately or strongly convex, with deep constrictions between the head and pronotum and between the pronotum and elytra.

The head capsule ( Figs 13 ̄14) is divided into the posterior 'neck' region and anterior, exposed part by an occipital constriction subequal to half width of the head. The anterior part of the head is about as long as broad or slightly elongate; vertex demarcated from the 'neck' region by a transverse impression and very weakly bulging posterodorsad; frons subtrapezoidal, transverse; antennal insertions moderately broadly separated; composite eyes located anterolaterally; tempora much longer than eyes, rounded and distinctly convergent caudad. The tempora and genae/postgenae are sparsely covered with long, thick bristles.

Mouthparts ( Figs 14 ̄15) similar to those in most species of Euconnus , except the mandibles, which are uniquely shaped, with a slender and strongly curved distal portion abruptly narrowed and delimited from a broad, subtriangular basal portion, the external mandibular margin strongly biarcuate. Hypostomal ridges ( Fig. 15 ; hr) long but not reaching posterior tentorial pits ( Fig. 15 ; ptp), the latter elongate, slot-like, hypostomal ridges not connected at middle and sinuate.

The antennae ( Figs 2 ̄3, 16̄19) moderately long and slender, in both sexes with distinctly delimited, tetramerous club, which in males is uniquely modified ( Figs 16 ̄19): antennomeres VIIĪIX are asymmetrical, with their mesal margins concave and lateral (external) margins convex, each has an elongate and densely serrate carina with its proximal (antennomere VIII) or distal (in some cases antennomeres VIII, always antennomere IX) portion forming a protruding subtriangular tooth. Between all marginal teeth of the carina deep openings can be seen, presumably of a glandular function ( Fig. 19 ). The antennomere X is often at least slightly asymmetrical, but lacking the mesal carina. Surface of all antennomeres, especially those of the club, is covered with conspicuous scale-like microsculpture, and distal subhorizontal surface of distal antennomeres is microgranulated.

The prothorax ( Figs 13 ̄20) of Cladoconnus is bell-shaped, typically about as long a broad, broadest clearly in front of middle, with sides rounded in anterior half and nearly parallel or concave posteriorly; anterior pronotal corners are indistinct, rounded, posterior corners well-marked, nearly right- or obtuse-angled, blunt. The pronotal base bears three pairs of very small but distinct antebasal pits (Fig. 134; abp) on each side forming a triangle, each of the inner pits is located in a large shallow and diffuse impression, impressions are separated at middle by a narrow but distinct longitudinal median carina ( Fig. 13 ; mc); additionally the pronotum bears narrow but distinct sublateral carinae ( Fig. 13 ; slc). In addition to thin setae, the pronotum bears thick and usually dense bristles on each side.

Ventral prothoracic structures are typical of Euconnus : the basisternal part of prosternum ( Fig. 20 ; bst) is much shorter than the coxal part; the intercoxal region bears a barely marked diffuse carina; notosternal sutures ( Fig. 20 ; nss) are complete; hypomeral ridges ( Fig. 20 ; hyr) complete and the inner (adcoxal) part of each hypomeron is distinctly microsculptured and asetose.

The mesoventrite ( Fig. 21 ) has a conspicuously long and well-defined anterior ridge, distinct anterior impressions functioning as procoxal rests ( Fig. 9 ; pcr), which are sharply demarcated anteriorly and separated at middle, but not demarcated posteriorly, and filled with sparse, moderately long setae, at least in their posterior halves. The mesoventral intercoxal process ( Fig. 21 ; msvp) is keel-like, anteriorly connected with the anterior ridge and posteriorly fused with metaventrite.

The mesoscutellum is not exposed in intact specimens ( Fig. 13 ).

The metaventrite ( Fig. 21 ) is slightly elongate; the metaventral intercoxal process ( Fig. 21 ; mtvp) is relatively broad, its posterior margin is concave, and posterolateral corners acute.

Each elytron bears two asetose, large and deep basal elytral foveae ( Fig. 13 ; bef).

The aedeagus in the type species of Cladoconnus ( Figs 22 ̄23), as in all other species of this subgenus (e.g., Hlaváč & Stevanović 2013) is relatively stout, drop-shaped, with moderately darkly sclerotized walls, always with several elongate, asymmetrically distributed endophallic sclerites and large ventral membranous diaphragm; parameres free, slender, with apical and subapical setae.

Conclusions. Cladoconnus has all the diagnostic characters of Euconnus (see Jałoszyński (2012), and can be maintained as a subgenus. Although it is similar to several other subgenera of Euconnus (e.g., Tetramelus ), it differs from all of them not only in the uniquely modified male antennae, but also in the mandibles with the strongly biarcuate external margins; and basal pronotal structures: a set of six antebasal pronotal pits grouped in two lateral triangles, a pair of sublateral carinae, the median carina and a pair of submedian impressions (in this combination not known in any other subgenus of Euconnus ).

Emended diagnosis of Euconnus (Cladoconnus) . Euconnus with distinctly tetramerous club; antennomeres VIII–IX and often X modified in males, asymmetrical, antennomeres VIII–IV with longitudinal mesal serrate carinae; head about as long as broad, with vertex indistinctly bulging posterodorsad; tempora longer than eyes and covered with bristles; hypostomal ridges long but not reaching posterior tentorial pits and not connected posteriorly; mandibles with strongly biarcuate external margins and rapidly narrowed, strongly curved slender distal portions; pronotum broadest distinctly in front of middle, with sides rounded anteriorly and nearly parallel or constricted posteriorly; pronotal base with six antebasal pronotal pits grouped in two lateral triangles, a pair of sublateral carinae, the median carina and a pair of submedian impressions; interprocoxal area with only an indistinct trace of carina; sides of pronotum with bristles; basal elytral foveae relatively large and deep; metaventral intercoxal process distinctly emarginate; aedeagus with asymmetrically distributed elongated endophallic sclerites.

Figures

FIGURES 1–3. Dorsal habitus. Euconnus (Androconnus) bechyneae Franz, male (1); Euconnus (Cladoconnus) motschulskyi (Sturm), male (2); Euconnus (Cladoconnus) denticornis (Müller & Kunze), female (3).

FIGURES 13–15. Morphological structures of Euconnus (Cladoconnus) motschulskyi (Sturm), male. Head, prothorax and elytral base in dorsal view (13); head in frontal (14) and ventral (15) views. Abbreviations: abp, antebasal pit; bef, basal elytral fovea; cl, clypeus; fcg, frontoclypeal groove; fr, frons; gp, gular plate; hr, hypostomal ridge; lbr, labrum; mc, median carina; md, mandible; mn, mentum; ptp,posterior tentorial pits; slc, sublateral carina; smn, submentum; vt, vertex.

FIGURES 16–19. Morphological structures of Euconnus (Cladoconnus) motschulskyi (Sturm), male. Distal portion of right antenna in dorsal view (16); antennomeres VIII–X in dorsal (17) and mesal (18) views; serrate carina of antennomere IX in mesal view (19).Abbreviations:anVIII–XI, antennomere VIII–X.

FIGURES 20–23. Morphological structures of Euconnus (Cladoconnus) motschulskyi (Sturm), male. Prothorax in ventral view (20); pterothorax in ventral view (21); aedeagus in ventral (22) and lateral (23) views.Abbreviations:bst, basisternal part of prosternum; hyr, hypomeral ridge; msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process; nss, notosternalsuture; pcr, procoxalrest.

FIGURES 9–12. Morphological structures of Euconnus (Androconnus) bechyneae Franz, male. Pterothorax and anterior portion ofabdomen inventral view (9); aedeagusinlateroventral (10), ventral (11) and lateral(12)views.Abbreviations:msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process; pcr, procoxal rest.