Euconnus (Tetramelus) tenuissimides Newton, 2024

Jałoszyński, Paweł, 2024, The ‘ curse of Horaeomorphus’ (almost) lifted. Revision of misplaced species from Madagascar, Comoros and Mascarenes (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 5505 (1), pp. 1-96 : 58-60

Euconnus (Tetramelus) tenuissimides Newton , stat rev.

( Figs 209–219 )

Euconnus (Anthicimorphus) tenuissimus Franz, 1986b: 254 . Preoccupied, not Euconnus tenuissimus Franz, 1982: 250 .

Horaeomorphus tenuissimus (Franz) ; Jałoszyński (2014b): 12 (result of placing Anthicimorphus as junior synonym of Horaeomorphus ).

Horaeomorphus tenuissimides Newton, 2017: 14 . New name for Euconnus tenuissimus Franz, 1986b: 254 .

Type material studied. Holotype (Madagascar): ♂, four labels: “Ambatolaona / VI. 57 A. R.” [white, printed], “INSTITUT / SCIENTIFIQUE / MADAGASCAR ” [bluish, printed], “ Euconnus / Anthicimorphus / tenuissimus m. / det. H.Franz ” [yellowish, handwritten and printed], “Typus” [red, handwritten] ( NHMW).

Revised diagnosis. Body ( Fig. 209 ) conspicuously slender, sides of vertex and pronotal disc with sparse bristles, elytra with short and sparse setae; head ( Figs 210–211 ) rhomboidal, with vertex posteriorly strongly rounded; pronotum ( Fig. 217 ) bell-shaped, broadest between middle and anterior third, with two pairs of small round antebasal pits; antenna ( Fig. 212 ) slender but short, with antennomeres 1–9 each elongate and 10 as long as broad; aedeagus ( Figs 213–214 ) in ventral view drop-shaped and broadest near middle, ventral apical wall broadly subtriangular, dorsal apical wall forming strongly elongate process with sub-parallel lateral margins and rounded apex, each paramere slender, not broadened, with several conspicuously long apical setae.

Redescription. Body of male ( Fig. 209 ) strongly elongate and flattened, light brown with lighter yellowishbrown elytra, legs (especially tarsi), antennae and palps slightly lighter; setae yellowish; BL 1.35 mm.

Head ( Figs 210–211 , 217–218 ) in anterodorsal view rhomboidal, about as long as broad, broadest at eyes, HL 0.23 mm, HW 0.25 mm; length of temple in lateral view ( Fig. 211 ) subequal to eye; vertex and frons confluent, together weakly convex and elongate; vertex posteriorly strongly rounded; each eye large and strongly convex but weakly projecting from head silhouette, not emarginate posteriorly. Frons and vertex virtually impunctate, sparsely covered with long suberect setae, lateral regions of vertex and genae with thick bristles ( Figs 217–218 ). Antenna ( Fig. 212 ) slender but short, as long as about half BL, with indistinctly delimited tetramerous club, AnL 0.70 mm, antennomeres 1–9 each elongate and 10 as long as broad, 11 much longer than 10 and similar in width, about 2.2 times as long as broad.

Pronotum ( Fig. 217 ) bell-shaped, broadest between middle and anterior third; PL 0.33 mm, PW 0.25 mm. Anterior margin strongly rounded, lateral margins weakly rounded in more than anterior half, weakly sinuate in posterior half; posterior corners blunt; posterior margin distinctly convex. Base with two pairs of small round pits ( Fig. 217 ). Disc impunctate and covered with sparse long suberect setae, bristles present on lateral areas and hypomera ( Figs 217–218 ).

Elytra together rhomboidal, broadest near middle where sides are slightly angulate; EL 0.80 mm, EW 0.38 mm, EI 2.13; humeral calli angulate and weakly elevated, basal elytral foveae vestigial but discernible ( Fig. 217 ). Elytra impunctate and sparsely covered with short suberect setae.

Meso- and metaventrite ( Fig. 219 ) with relatively dense, short and recumbent setae (metaventrite in studied specimen with most setae broken off).

Legs long and slender, unmodified.

Aedeagus ( Figs 213–214 ) stout, AeL 0.25 mm; in ventral view drop-shaped, broadest near middle, distally gradually narrowing; ventral apical wall broadly subtriangular and short, dorsal apical wall much longer and forming narrow process with sub-parallel lateral margins and with rounded distal margin, endophallic sclerites complex and asymmetrical, with conspicuous elongate, curved and pointed dark distomedian sclerite; each paramere slender, with several conspicuously long apical setae

Female. Unknown.

Distribution. Central Madagascar (Analamanga Region).

Remarks. Euconnus tenuissimides is one of the most remarkable and easy to identify Malagasy Tetramelus . The male is small-bodied, conspicuously slender, with head and pronotum equal in width, large oval eyes, rhomboidal elytra over twice as long as broad, with nearly angulate widest site, and unique aedeagal structures.

In addition to the holotype male deposited in Franz Coll. ( NHMW), Franz (1986b) mentions also one paratype male deposited in Muséum National d'Histoire Naturelle, Paris, both with the same collecting data .

Figures

FIGURES 209–216. Euconnus (Tetramelus) tenuissimides Newton, holotype. Habitus in dorsal view (209); head in anterodorsal view (210); head and prothorax in lateral view (only bristles on head are shown) (211); antenna (212); aedeagus in ventral (213, 215) and lateral (214, 216) views.

FIGURES 217–219. Euconnus (Tetramelus) tenuissimides Newton, holotype. Head, prothorax and elytral base in dorsal view (217); head, prothorax and anterior region of mesothorax in ventral view (218); pterothorax in ventral view (219). Abbreviations: abp, antebasal pit; bef, basal elytral fovea; gp, gular plate; hr, hypomeral ridge; hyr, hypomeral ridge; msvp, mesoventral intermesocoxal process; mtvp, metaventral process; nss, notosternal suture; pcr, procoxal rest; ptp, posterior tentorial pit; smn, submentum.