Austrostenichnus Franz

Jałoszyński, Paweł, 2013, Revision of subgenera of Stenichnus Thomson, with review of Australo-Pacific species (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 3630 (1), pp. 39-79: 54-55

publication ID

http://dx.doi.org/10.11646/zootaxa.3630.1.2

publication LSID

lsid:zoobank.org:pub:A338EE37-E8AC-4AC3-8D6B-D0177FB680BF

DOI

http://doi.org/10.5281/zenodo.5696218

persistent identifier

http://treatment.plazi.org/id/03D687E5-B05F-9A6B-BDD1-42EB1742F89B

treatment provided by

Plazi

scientific name

Austrostenichnus Franz
status

 

Genus Austrostenichnus Franz   , stat. nov.

Austrostenichnus Franz, 1971: 45   (as subgenus of Stenichnus   ). Type species: Stenichnus caledonicus Franz, 1971   (monotypy).

Revised diagnosis. Eyes located posteriorly; occipital constriction nearly as broad as vertex; fronto-clypeal groove absent; mandibles subtriangular, with broad and abruptly demarcated basal part and subapical tooth on mesal margin; submentum trapezoidal, completely demarcated from hypostomae by lateral sutures; hypostomae elongate and demarcated from genae by complete hypostomal ridges; posterior tentorial pits hidden in deep groove separating submentum from gular plate; antennae gradually thickening distally; pronotum with one pair of lateral ante-basal pits connected by transverse groove, without lateral marginal carinae; prosternum with moderately narrow basisternal part demarcated from procoxal cavities by carina, procoxal cavities not separated in middle; hypomera not demarcated from pronotum; mesoventrite with asetose impressions not separated in middle and setose lateral impressions broadly separated in middle and broadly separated from mesocoxal cavities; mesoventral intercoxal process broad and nearly flat, posteriorly fused with metaventrite; mesocoxal projections with posterior lobes; metaventrite without metaventral anterior process, with short and broad metaventral intercoxal projection bearing median notch; aedeagus with free parameres.

Redescription. Body ( Figs. 52–53 View FIGURES 52 – 56 ) strongly convex, strongly elongate and slender, with long appendages, cuticle glossy, distinctly setose.

Head ( Figs. 57–59 View FIGURES 57 – 61 ) subtriangular, broadest at posteriorly located eyes; neck region ( Fig. 58 View FIGURES 57 – 61 ; nr) short and subcylindrical, only slightly broadened in middle; occipital constriction ( Figs. 58–59 View FIGURES 57 – 61 ; occ) in the narrowest place as wide as vertex; tempora ( Fig. 58 View FIGURES 57 – 61 ; tm) much shorter than eyes; vertex ( Fig. 58 View FIGURES 57 – 61 ; vt) and frons ( Fig. 58 View FIGURES 57 – 61 ; fr) between eyes confluent and convex, frons between antennal insertions flattened; fronto-clypeal groove absent.

Labrum ( Figs. 58–59 View FIGURES 57 – 61 ; lb) transverse with rounded sides and anterior margin. Mandibles ( Fig. 58 View FIGURES 57 – 61 ; md) symmetrical, each with broad basal part and abruptly demarcated, moderately slender distal part, without noticeable prostheca, mesal margin with median tooth.

Each maxilla with elongate galea and lacinia ( Fig. 59 View FIGURES 57 – 61 ; gal, lac) and long maxillary palp ( Fig. 59 View FIGURES 57 – 61 ; mxp) composed of minute palpomere I, strongly elongate and broadening distally palpomere II, long and pedunculate palpomere III broadest near middle and slender, strongly elongate subconical and pointed palpomere IV.

Labium with trapezoidal submentum ( Fig. 59 View FIGURES 57 – 61 ; smn) posteriorly demarcated from gular plate ( Fig. 59 View FIGURES 57 – 61 ; gp) by deep transverse groove in which posterior tentorial pits are hidden, laterally demarcated from hypostomae ( Fig. 59 View FIGURES 57 – 61 ; h) by complete lateral sutures ( Fig. 59 View FIGURES 57 – 61 ; lss); mentum subtrapezoidal ( Fig. 59 View FIGURES 57 – 61 ; mn); prementum short with narrowly separated, small 3 -segmented labial palps ( Fig. 52 View FIGURES 52 – 56 ; lp). Laterally mouthparts demarcated from genae by long and complete hypostomal ridges ( Fig. 59 View FIGURES 57 – 61 ; hr).

Gular plate ( Fig. 59 View FIGURES 57 – 61 ; gp) large and trapezoidal in shape, with distinct gular sutures ( Fig. 59 View FIGURES 57 – 61 ; gs).

Antennae ( Figs. 52–53 View FIGURES 52 – 56 ) gradually thickening towards apices, slender.

Prothorax ( Figs. 52 –53 View FIGURES 52 – 56 , 57, 60 View FIGURES 57 – 61 ) in dorsal view with rounded anterior and lateral margins of pronotum, at base with transverse groove connecting one pair of lateral ante-basal foveae, without lateral marginal carinae or edges; hypomera ( Fig. 60 View FIGURES 57 – 61 ; hy) not demarcated from notum. Prosternum ( Fig. 60 View FIGURES 57 – 61 ) with moderately short basisternal part ( Fig. 60 View FIGURES 57 – 61 ; bs); procoxal cavities ( Fig. 60 View FIGURES 57 – 61 ; pcc) with anterior marginal carina and not separated in middle; procoxal sockets ( Fig. 60 View FIGURES 57 – 61 ; pcs) closed by lateral expansion of sternum; notosternal sutures ( Fig. 60 View FIGURES 57 – 61 ; nss) complete.

Mesoventrite ( Figs. 57, 61 View FIGURES 57 – 61 ) with narrow anterior ridge ( Fig. 61 View FIGURES 57 – 61 ; ar), lateral asetose impressions ( Fig. 61 View FIGURES 57 – 61 ; ai) not separated in middle and large lateral setose impressions ( Fig. 61 View FIGURES 57 – 61 ; si) broadly separated in middle and broadly separated from mesocoxal cavities ( Fig. 61 View FIGURES 57 – 61 ; mscc); mesocoxal projection ( Fig. 61 View FIGURES 57 – 61 ; mcp) without carina and with posterior lobe ( Fig. 61 View FIGURES 57 – 61 ; pl) bearing dense setae along posterior margin; mesoventral intercoxal process ( Fig. 61 View FIGURES 57 – 61 ; msvp) relatively broad and nearly flat, posteriorly fused to metaventrite

Metaventrite ( Figs. 57, 61 View FIGURES 57 – 61 ) broader than long, without metaventral anterior process; metaventral intercoxal process ( Fig. 61 View FIGURES 57 – 61 ; mtvp) broad and short, with distinct median notch.

Elytra ( Figs. 52–53 View FIGURES 52 – 56 ) oval, with well-marked humeral calli; each elytron with one rudimentary basal fovea barely noticeable in dry-mounted specimens. Hind wings well-developed.

Legs ( Figs. 52–53 View FIGURES 52 – 56 ) long and slender; femora clavate, tibiae nearly straight, tarsi strongly elongate.

Abdominal sternites VII and VIII separated by indistinct suture.

Aedeagus ( Figs. 55–56 View FIGURES 52 – 56 ) with complex and symmetrical internal armature composed of elongate, moderately darkly sclerotized structures; parameres free and slender, with apical setae.

Distribution and composition. Three species were described in Stenichnus (Austrostenichnus)   , one from New Caledonia and two from New Zealand. However, the species from New Zealand clearly represent a separate genus described in a further part of this paper, and Austrostenichnus   , elevated here to the genus rank, comprises only A. caledonicus   known to occur in southern New Caledonia.

Remarks. Austrostenichnus   differs from Stenichnus   in the lack of fronto-clypeal groove; different shape of mandibles; different sculpture of the basal part of pronotum; lack of prosternal carina separating procoxal cavities; the mesoventrite bearing asetose impressions confluent in middle and broadly separated setose impressions; the shape of mesoventral intercoxal process; lack of carina on mesocoxal projection; lack of metaventral anterior process; and the elytral base with only one rudimentary fovea (major differences are compiled in Table 1 View TABLE 1 ). Such a large number of significant differences justifies the placement of Austrostenichnus   as a separate genus.

Although in the available specimens it was not possible to examine details of the prementum, the approximate bases of labial palps suggest that labial discs, characteristic of Stenichnus   , are absent.