Euconnus (Alloconophron) Jałoszyński 2017
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scydmaenidae
Euconnus

description: 1. Morphological structures of Euconnus (Alloconophron) and Anhoraeomorphus
The general body shape of Euconnus (Alloconophron) grucheti (Fig. 1) is very similar to that of Anhoraeomorphus obscurus (Fig. 3); adults of both species are moderately slender, with deep constrictions between head and pronotum and between pronotum and elytra, have a similar shape of each body part in dorsal view, and similarly distributed setae and bristles.
The head capsule of both taxa (Figs 2, 4 ¯5, 10¯11) is divided into the posterior 'neck' region and anterior, exposed part by an occipital constriction slightly broader than half width of head. The anterior part of the head is distinctly elongate (in Figs 4 ¯5 and 10¯11 the head is tilted anteriorly; head in both taxa is ~ 1.2 × as long as broad); vertex demarcated from the 'neck' region by a transverse impression and bulging posterodorsally (Fig. 2); frons subtrapezoidal; antennal insertions moderately broadly separated; compound eyes located anterolaterally, so that the tempora are long. The tempora and genae are covered with thick bristles (Figs 4, 10). The frons is distinctly impressed at middle in E. grucheti, E. impressifrons and A. obscurus, and indistinctly so in A. assimilis; the impression is sharply defined, small and elongate in both species of Alloconophron and diffuse, round and large in A. obscurus, only in the latter species there is a shallow and diffuse transverse impression behind each supraantennal tubercle. Supraantennal tubercles in all species are conspicuously prominent, frons in front of them strongly declines and is demarcated from clypeus by a distinct and long frontoclypeal groove.
Mouthparts in Alloconophron and Anhoraeomorphus are similar; mandibles in all studied specimens are tightly closed and their structural details were not possible to study; their general shape is subtriangular and flattened; mentum subtrapezoidal with narrowly separated and unremarkable labial palps; submentum (Figs 4, 10; smn) very short, strongly transverse, posteriorly demarcated by complete and connected hypostomal ridges (Figs 4, 10; hr) which run parallel to the posterior margins of cardines and meet at middle, forming a single transverse ridge. Differences between Alloconophron and Anhoraeomorphus can be seen in maxillary palpomeres III and IV. The palpomere III in Alloconophron (Fig. 5) is relatively slender, unremarkable, and the subconical palpomere IV is elongate, with a narrow, almost pointed apex. In Anhoraeomorphus (Fig. 11) the palpomere III is distinctly thickened, and palpomere IV is short, broadly subconical, with a relatively blunt apex. The tentorial pits in all studied species are elongate, slot-like; those in Alloconophron are well-visible, whereas pits in Anhoraeomorphus are obscured by dense bristles.
The antennae (Figs 1, 3) of both taxa are moderately long in relation to the body length, with scape and pedicel elongate; five distal antennomeres forming indistinctly delimited club, which is slender and sparsely setose in E. grucheti and conspicuously broad and densely setose in both species of Anhoraeomorphus; in E. impressifrons the antennal club is intermediary in width between the forms of E. grucheti and Anhoraeomorphus and covered with sparse setae.
The prothorax (Figs 4, 10) of all studied species is bell-shaped, slightly elongate, broadest behind middle, with rounded sides and more narrowing anteriorly than posteriorly (in A. assimilis only indistinctly narrowing posteriorly), so that the anterior pronotal margin is shorter than posterior margin; anterior and posterior corners well-defined but obtuse-angled and blunt. Antebasal structures slightly differ between Alloconophron and Anhoraeomorphus, they are variable within the latter taxon. In E. grucheti and E. impressifrons there are two pairs of small but distinct antebasal pits (Fig. 4; abp) and vestigial, barely discernible sublateral carinae (Fig. 4; slc); in A. obscurus (Fig. 10) there are only two shallow and diffuse impressions and similarly vestigial sublateral carinae; in A. assimilis the antebasal structures resemble those in Alloconophron, but the antebasal pits are slightly larger. In all species the prothorax bears thick and dense setae on sides and anterior portions of hypomera, additionally with a variously distinct patch of bristles anterodorsally.
Ventral prothoracic structures differ between Alloconophron (Fig. 5) and Anhoraeomorphus (Fig. 11) only in hypomeral ridges. The basisternal part of prosternum (Figs 5, 11; bst) is shorter than the coxal part and densely setose; intercoxal region lacks process or carina; notosternal sutures (Figs 5, 11; nss) are complete; hypomeral ridges (Figs 5, 11; hyr) in Alloconophron are complete and the inner (adcoxal) part of hypomera is distinctly microsculptured, in Anhoraeomorphus hypomeral ridges are marked only posteriorly (distinctly in A. obscurus, weakly so in A. assimilis), and the inner (adcoxal) portion of hypomera is weakly sculptured.
The mesoventral structures in all studied species are similar; Alloconophron and Anhoraeomorphus share the broad and well-defined anterior ridge (Figs 6, 12; ar), distinct but shallow anterior impressions functioning as procoxal rests (Figs 6, 12; pcr), which are sharply demarcated anteriorly and separated at middle, but not demarcated posteriorly and filled with short setae. All species have also a carinate but weakly elevated mesoventral process (Figs 6, 12; msvp), which anteriorly connects with the anterior ridge and posteriorly is fused with metaventrite, its portion between procoxal rests is most elevated.
The mesoscutellum in all studied species is not exposed in intact specimens (Figs 4, 10).
Metaventral structures in Alloconophron and Anhoraeomorphus are identical; the metaventrite is slightly or distinctly transverse, and the metaventral intercoxal process (Figs 6, 12; mtvp) is short, broadly subtriangular, with a distinct posteromedian notch.
The elytra in studied species differ only in variously distinct, but in all cases two, basal elytral foveae; those in E. grucheti (Fig. 4; bef) and A. obscurus (Fig. 10; bef) are very small and barely discernible, in A. obscurus the foveae are slightly larger, but still unremarkable.
The aedeagus is known only in Alloconophron (Figs 7 ¯8); it has the median lobe symmetrical, relatively welldefined and asymmetrical sclerotized endophallic structures, and free, slender parameres.
Conclusions. Alloconophron and Anhoraeomorphus differ slightly in the vestiture of antennal clubs, shape of the maxillary palpomeres III and IV, and length of the hypomeral ridges. They share all remaining structures, and therefore the differences are too weak to serve as diagnostic characters of two separate genera. Moreover, the subtriangular and narrowly notched metaventral intercoxal process very narrowly separating metacoxae excludes Alloconophron from Euconnus. Consequently, Alloconophron is removed from Euconnus and placed as a subgenus of Anhoraeomorphus.
Remarks. Anhoraeomorphus and Euconnus (Nodoconnus), both known to occur only in Madagascar, are the only Glandulariini with the fused hypostomal ridges forming a single transverse ridge just behind the submentum, running parallel to the posterior margin of mentum. Nodoconnus has the metacoxae broadly separated, and therefore was retained as a subgenus of Euconnus (Jałoszyński 2017d).
Emended diagnosis of the genus Anhoraeomorphus. Body moderately slender, elongate, broadening posteriorly; antenna with indistinctly delimited pentamerous club; head elongate, with vertex bulging posterodorsally; occipital constriction slightly broader than half width of head; tempora, vertex, genae and postgenae with thick bristles; submentum lacking lateral sutures, very short and transverse, posteriorly demarcated by hypostomal ridges which run mesally parallel to posterior margins of cardines and are connected at middle, forming one transverse ridge; pronotum bell-shaped, broadest behind middle, more narrowing anteriorly than posteriorly, with four small antebasal pits (can be reduced to diffuse impressions) and rudimentary sublateral carinae, with bristles laterally and lateroventrally; prosternum lacking intercoxal process or carina; notosternal sutures complete; hypomeral ridges complete or anteriorly obliterated; mesoventral intercoxal process carinate, weakly elevated, running from anterior ridge to posterior margins of mesocoxal cavities; metaventral intercoxal process subtriangular, narrowly notched at middle and very narrowly separating metacoxae; each elytron with two small asetose basal foveae; aedeagus with free parameres.
Anhoraeomorphus is divided here into two subgenera; their diagnostic characters are listed in the identification key:
1. Antennal club covered with conspicuously dense and long setae; maxillary palpomere III conspicuously broadened, 2¯2.5 × as long as broad; maxillary palpomere IV stout, about as long as broad at base; hypomeral ridges obliterated anteriorly, marked only in posterior portion of hypomera................................................... Anhoraeomorphus s. str.
- Antennal club covered with unremarkable, sparse setae; maxillary palpomere III slender, about 3 × as long as broad; maxillary palpomere IV distinctly elongate; hypomeral ridges complete........................... subgen. Alloconophron stat. n.
description: Published as part of Jałoszyński, Paweł, 2017, Taxonomy of ' Euconnus complex'. Part XVI. Alloconophron Franz transferred to Anhoraeomorphus Franz as subgenus, with notes on systematic position of Noctophus Casey (Coleoptera, Staphylinidae, Scydmaeninae) in Zootaxa 4358 (2), DOI: 10.11646/zootaxa.4358.2.6, http://zenodo.org/record/1068376