Stenichnodes Franz

Jałoszyński, Paweł, 2015, Taxonomy of the Alloraphes-Stenichnaphes-Parastenichnaphes complex: Stenichnodes complicates the picture (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 3990 (2), pp. 279-286 : 280-282

Stenichnodes Franz

Stenichnodes Franz, 1966: 626 . Type species: Stenichnodes saheliensis Franz, 1966 (orig. des.).

Revised diagnosis. Body elongate and slender, with distinct constrictions between head and pronotum and between pronotum and elytra; head in dorsal view approximately subtriangular, with vertex not expanded dorsoposteriorly; occipital constriction nearly as broad as vertex; thick and long bristles on head and prothorax absent; frontoclypeal groove absent; tempora rudimentary and posterior margins of eyes nearly adjacent to occipital constriction; submentum demarcated laterally from hypostomae by sutures; antennae gradually thickening distally; pronotum without lateral carinae or edges; base of pronotum with transverse groove connected at each end to small lateral pit; basisternal part of prosternum shorter than procoxal cavities; prosternum with very narrow carinate prosternal intercoxal process with pointed posterior margin; prothoracic hypomeral ridges present; pronotosternal sutures anteriorly internalized and in dry-mounted specimens visible only posteriorly; mesoventral intercoxal process developed as long and narrow carina extending from anterior ridge of mesoventrite to posterior margin of mesocoxae; mesoventrite with asetose lateral impressions behind anterior ridge (= procoxal rests); mesothorax without lateral foveae; mesocoxal projection with inconspicuous posterior lobe; metacoxae contiguous; metaventral intercoxal process subtrapezoidal with median notch; each elytron with one asetose rudiment of basal fovea; aedeagus without parameres, with basally located diaphragm internally connected to long apophysis.

Redescription. Body of male ( Fig. 1 ) moderately convex, elongate and slender, with long appendages, BL <1 mm; cuticle glossy, light brown, covered with sparse setae.

Head ( Fig. 3 ) with anterior part (in front of occipital constriction) subtriangular, with large eyes; occipital constriction ( Fig. 3 ; occ) nearly as broad as vertex; tempora rudimentary, without bristles; vertex broader than long, weakly convex; frons confluent with vertex, subtriangular; frontoclypeal groove absent; antennal insertions moderately broadly separated.

Labrum transverse with rounded anterior margin.

Mandibles ( Fig. 3 ; md) symmetrical, subtriangular, each with broad base and slender, strongly curved apical tooth, with small mesal subapical denticle; mesal basal margin not visible in studied specimen.

Each maxilla with subtriangular basistipes, broad mediostipes, elongate galea ( Fig. 3 ; gal) and lacinia ( Fig. 3 ; lac) and strongly elongate and large maxillary palp ( Fig. 3 ; mxp) composed of minute but strongly elongate palpomere I, strongly elongate, pedunculate and slender palpomere II, large and strongly elongate palpomere III broadest between basal third and middle, and long, slender, subconical and pointed palpomere IV with indistinctly delimited apical part.

Labium with subtrapezoidal submentum ( Fig. 3 ; smn) distinctly demarcated posteriorly from gular plate by transverse impression and laterally demarcated from postcardinal portions of hypostomae by lateral sutures ( Fig. 3 ; lss); subtrapezoidal mentum ( Fig. 3 ; mn); and long prementum bearing narrowly separated at bases long 3- segmented labial palps with especially elongate palpomere III ( Fig. 3 ; lp3) ligula not demarcated. Hypostomal ridges ( Fig. 3 ; hr) distinct and extending to posterior tentorial pits.

Gular plate ( Fig. 3 ; gp) large and distinctly narrowing anteriorly; gular sutures ( Fig. 3 ; gs) distinct; posterior tentorial pits not discernible in ventral view, hidden in transverse groove demarcating base of submentum from gular plate.

Antennae ( Fig. 1 ) slender, gradually thickening distally.

Pronotum in dorsal view approximately bell-shaped, with rounded anterior margin and anterior parts of lateral margins, without anterior corners, sides narrowing posteriorly; hind corners obtuse-angled and blunt; posterior margin weakly arcuate; lateral marginal carinae absent; base of pronotum with distinct arcuate transverse groove connecting one lateral pair of shallow pits, additional indistinct and very small pit is located more laterally to each inner pit; sublateral carinae absent; pronotum only with thin setae, without thick bristles.

Prosternum ( Fig. 4 ) with short basisternal part ( Fig. 4 ; bst) demarcated from procoxal cavities ( Fig. 4 ; pcc) by carina; median part of sternum with narrow and weakly elevated prosternal intercoxal process ( Fig. 4 ; psp); procoxal sockets ( Fig. 4 ; pcs) closed by narrow posterolateral lobes of prosternum; hypomera ( Fig. 4 ; hy) elongate, divided by complete hypomeral ridges ( Fig. 4 ; hyr) into narrow inner and broad external part; pronotosternal sutures ( Fig. 4 ; nss) nearly entire but anteriorly internalized and externally not marked, visible only in transparent mounts.

Mesonotum with small, subtriangular mesoscutellum not visible between bases of elytra in intact specimens, mesoscutoscutellar suture present.

Mesoventrite ( Fig. 5 ) with narrow anterior ridge ( Fig. 5 ; ar); mesoventral intercoxal process ( Fig. 5 ; msvp) developed as narrow and long, moderately elevated carina extending from anterior ridge to posterior margins of mesocoxae; lateral asetose impressions functioning as procoxal rests ( Fig. 5 ; pr) present, subtriangular; mesanepisternum with moderately long prepectus ( Fig. 5 ; pre) and posterior portion only partly visible in ventral view; mesepimeron not visible in ventral view; sides of mesothorax without foveae; mesocoxal projections ( Fig. 5 ; mcp) prominent but weakly expanding laterally, with mesocoxal sockets ( Fig. 5 ; mscs) located on their mesoventral surface and with posterior lobes not exposed.

Metaventrite ( Fig. 5 ; v3) subtrapezoidal, anteriorly fused with mesoventrite, without metaventral anterior process; posteriorly metaventrite shallowly bisinuate and with subtrapezoidal metaventral intercoxal process ( Fig. 5 ; mtvp) deeply and narrowly notched in middle. Metanepisterna and metepimera narrow.

Metendosternite (metafurca) ( Fig. 5 ) with short stalk and divergent lateral metafurcal arms ( Fig. 5 ; lmfa).

Elytra ( Fig. 1 ) oval, each with one asetose rudiment of basal fovea barely discernible even in transparent mounts; humeral calli elongate and distinct; subhumeral lines absent.

Hind wings well-developed, about twice as long as elytra.

Legs ( Figs. 1 , 4, 5 ) moderately long and slender; procoxae subglobose, mesocoxae oval, metacoxae strongly transverse; all trochanters short; all femora weakly clavate; tibiae long and straight; tarsi slender.

Abdominal sternites unmodified, suture between VII and VIII distinct.

Aedeagus ( Figs. 6–7 ) with slightly asymmetrical and thin-walled median lobe, without parameres, diaphragm located basally and internally connected to long apophysis.

Remarks. Morphological structures of Stenichnodes saheliensis differ from those of Parastenichnaphes only in the notosternal sutures of prothorax internalized anteriorly; the prosternal process narrowly carinate (and not subtriangular); and the presence of lateral metaventral carinae ( Fig. 5 ; mtvc). Therefore, Parastenichnaphes is here reduced to the subgenus of Stenichnodes , resulting in two new combinations: Stenichnodes (Parastenichnaphes) ceylonensis Franz , comb. n. and Stenichnodes (Parastenichnaphes) sumatrensis Franz , comb. n.

Alloraphes , Stenichnaphes and Stenichnodes show very uniform appearance and cannot be distinguished on the basis of dorsal characters ( Figs 8 –10). Major morphological differences and key characters are compiled in Table 1 .

Figures

FIGURES 1 – 2. Doral habitus (1) and original set of labels (2) of the holotype male of Stenichnodes saheliensis Franz.

FIGURES 3 – 7. Morphological structures of Stenichnodes saheliensis Franz. Head in ventral view (3), prothorax in ventral view (4), pterothorax and abdomen in ventral view (5), aedeagus in ventral (6) and lateral (7) views. Abbreviations: ar, anterior ridge of mesoventrite; bst, basisternal part of prosternum; gal, galea; gp, gular plate; gs, gular suture; hr, hypostomal ridge; hy, hypomeron; hyr, hypomeral ridge; lac, lacinia; lmfa, lateral metafurcal arm; lp 3, labial palpomere III; lss, lateral suture of submentum; mcp, mesocoxal projection; md, mandible; mn, mentum; mscc, mesocoxal cavity; mscs, mesocoxal socket; msvp, mesoventral intercoxal process; mtvc, metaventral lateral carina; mtvp, metaventral intercoxal process; mxp, maxillary palpomere; nss, pronotosternal suture; occ, occipital constriction; pcc, procoxal cavity; pcs, procoxal socket; pff, profurcal fovea; pr, procoxal rest; pre, prepectus; psp, prosternal process; smn, submentum; v 3, metaventrite.

FIGURES 8 – 9. Comparison of dorsal habitus of Stenichnodes (Parastenichnaphes) ceylonensis (Franz) (8); Alloraphes peruanus Franz (9) and Stenichnaphes urbanus Franz (10).