Euconnus
Creators: name: Jałoszyński, Paweł
name: Newton, Alfred F.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scydmaenidae
Euconnus

description: Euconnus (Austroconophron Franz, status rest.)
(Figs 1, 10–13, 30–31, 42)
Austroconophron Franz, 1971: 69 (as subgenus of Euconnus). Type specIes: Euconnus tindoui Franz, 1971 (des. orIg.). SynonymIzed wIth Sciacharis s. str. by Franz (1986a); here removed from synonymy and resurrected as subgenus of Euconnus.
Revised diagnosis. Euconnus with the following combination of characters: antennae gradually thickened; pronotum suboval with weakly marked anterior and posterior corners, strongly rounded sides, broadest in front of middle, lacking antebasal pits, grooves and sublateral carinae; basal elytral foveae vestigial; procoxal rests on mesoventrite with diffuse posterior margins; metaventral intermetacoxal process narrower than 1/3 of metaventral width, deeply emarginate; bristles present on head and prothorax but on the latter restricted to small anteroventral area.
Redescription. General body shape (Fig. 1) strongly elongate and strongly convex, body deeply constricted between head and pronotum and between pronotum and elytra.
Head (Figs 10–11) large in relation to pronotum; divided by occipital constriction into large anterior and small posterior part ('neck' region), posterior part retracted into pronotum. Occipital constriction slightly broader than half width of head. Anterior part of head capsule convex dorsally and flattened ventrally, rounded hexagonal; tempora longer than compound eyes; vertex transverse and not bulging posterodorsally, with posterior margin marked by rounded ridge, anteriorly vertex confluent with subtrapezoidal frons; supraantennal tubercles feebly marked; frontoclypeal groove distinct, deep. Gular plate (Fig. 11; gp) broad and with distinct gular sutures; posterior tentorial pits (Fig. 11; ptp) strongly elongate, slot-shaped and located in front of transverse impression separating 'neck' region from anterior part of head. Tempora, genae and postgenae with thick bristles. Submentum (Fig. 11; smn) subtriangular; hypostomal ridges (Fig. 11; hr) nearly complete, sinuate, not connected with posterior tentorial pits; mentum (Fig. 11; mn) subtrapezoidal; prementum small and transverse, largely membranous; labial palps short; maxillae generalized, as in all subgenera of Euconnus; mandibles only partly visible in the studied specimen, subtriangular and evenly curved, each with one preapical mesal tooth.
Antennae (Fig. 1) long and slender, gradually and distinctly thickened.
Prothorax (Figs 10–12) convex, elongate, broadest in front of middle, with strongly rounded sides and weakly marked, obtuse-angled anterior and posterior corners; pronotum lacking sublateral carinae, antebasal pits or grooves. Small anteroventral area on each side of prothorax covered with thick bristles. Prosternum with basisternal part (Fig. 12; bst) much shorter than coxal part; interprocoxal area with narrow and weakly elevated carina. Hypomeral ridges (Fig. 12; hyr) and notosternal sutures (Fig. 12; nss) complete.
Mesothorax. Mesoscutellum in intact specimens entirely covered by posterior pronotal margin, its posterior tip not exceeding posterior margin of elytral articulating lobe. Mesoventrite (Figs 12–13) with a pair of transverse setose impressions functioning as procoxal rests (Figs 12–13; pcr) in anterior region, impressions separated at middle and with diffuse posterior margins; mesoventral intercoxal process (Fig. 13; msvp) carinate.
Metathorax. Metaventrite (Fig. 13) much longer than mesoventrite, subtrapezoidal; intermetacoxal area weakly expanded posteriorly and forming short and relatively narrow metaventral intercoxal process (Fig. 13; mtvp) with strongly concave posteromedian margin.
Elytra (Figs 1, 10) oval, with rounded apices and narrow base which is subequal in width to posterior pronotal margin; humeral calli and basal impressions absent; each elytron with two barely discernible and asetose rudiments of basal foveae.
Metathoracic wings absent.
Legs (Fig. 1) moderately long and slender, unmodified.
Abdomen elongate, gradually narrowing posteriorly, suture between two terminal visible sternites (i.e., VII and VIII) less distinct than between remaining sternites.
Aedeagus (Figs 30–31) large, with symmetrical median lobe, heavily sclerotized, with modified apical region, in lateral view median lobe curved and with distinct collar surrounding basal foramen; parameres slender, with apical setae.
Remarks. The type species of Austroconophron, Euconnus tindoui (Fig. 1), has the metaventral intermetacoxal process (Fig. 13; mtvp) relatively narrow, but it clearly separates metacoxae, whereas in Sciacharis s. str. the metacoxae are contiguous (Jałoszyński 2014a). This character excludes Austroconophron from Sciacharis. Besides the separated metacoxae, the placement of Austroconophron in Euconnus is supported by strongly elevated and carinate mesoventral intercoxal process (Fig. 13; msvp); two (although vestigial) basal elytral foveae; and the prothorax with complete notosternal sutures, hypomeral ridges, short basisternal portion of prosternum and interprocoxal region with a barely discernible carina. Moreover, the aedeagus of E. tindoui (Figs 30–31) is not thin-walled and approximately drop- or bottle-shaped, as that in Sciacharis s. str., but it has a heavily sclerotized dorsal wall of the median lobe and a strongly modified apical region, both structures frequently found among species of Euconnus.
Austroconophron resembles Tetramelus Motschulsky, 1870 in the general body shape, antennal structure and the elytra with reduced basal structures, even more so than in Tetramelus, which lacks humeral calli due to the loss of wings, but has a pair of distinct and deep basal elytral foveae; the latter are rudimentary in Austroconophron. These subgenera can be easily distinguished on the basis of cephalic, prothoracic and metaventral structures. Tetramelus has the vertex bulging posterodorsally; the sides of pronotum sinuate, distinctly concave behind the broadest site, distinct antebasal pits and sublateral carinae, and often also a median antebasal longitudinal carina; and the intermetacoxal process at least as broad as 1/4 of metaventral width (often broader).
Composition and distribution. Euconnus (Austroconophron) currently includes 21 valid species names; all species occur in New Caledonia.
Lectotype designation. Franz (1971) mentioned two specimens included in the type series of Euconnus tindoui Franz, 1971, but did not fix one as holotype. Consequently, the two specimens preserved at NHMW are syntypes. The male (Fig. 1) with the aedeagus extracted (Figs 30–31) bearing the set of labels illustrated in Fig. 42, is here designated as the lectotype (des. P. Jałoszyński).
description: Published as part of Jałoszyński, Paweł & Newton, Alfred F., 2017, Taxonomy of ' Euconnus complex'. Part XV. Disentangling the Euconnus - Sciacharis knot (Coleoptera, Staphylinidae, Scydmaeninae), pp. 401-443 in Zootaxa 4344 (3) on pages 403-407, DOI: 10.11646/zootaxa.4344.3.1, http://zenodo.org/record/1043637