Pselaphogenius Reitter, 1910

Owens, Brittany E. & Carlton, Christopher E., 2022, --- Revision- -- of- -- the- -- New- -- Zealand- -- species- -- of- -- the- -- Genus- -- Pselaphogenius Reitter- -- (Staphylinidae: --- Pselaphinae: --- Pselaphitae: --- Pselaphini) ---, Zootaxa 5155 (2), pp. 187-220 : 188-191

Pselaphogenius Reitter ­­­1910

Pselaphogenius Reitter 1910: 155 (as subgenus of Pselaphostomus ).

Type species: Pselaphus quadricostatus Reitter (design. Jeannel 1950: 389).

Pselaphodinus Jeannel 1950: 389 (as subgenus of Pselaphopsis )

Type species: Pselaphus longipalpis Kiesenwetter (design. orig. descr.).

Redescription. Males. Head: Eyes of variable size, may be reduced.Vertex convex, shallow sulcus beginning at base of vertex, extending to level of vertexal foveae; vertexal foveae large, set into margins of vertexal depression parallel to middle of eyes; vertexal depression widest between eyes, confluent with sulcus extending to apex of rostrum. Rostral sulcus bounded by lateral, flattened ridges extending to antennal acetabula. Frontal margin of rostrum acute to gently curved in dorsal view, apex often with notch bearing squamous setae. Antennal segment one as long as antennomeres 2-4, antennae otherwise unmodified. Gular mound modified, usually as long as wide, glabrous; area of head posterior to gular mound flattened, slightly concave, usually without flattened modified scales; gular foveae present, paired. Maxillary palpomere I elongate, 1/2 as long as palpomere II; palpomere II narrow, enlarged distally, as long as or longer than head; maxillary palpomere III quadrate; maxillary palpomere IV as long as or longer than head, narrow, widened in distal 1/3-1/4, apical area smooth to weakly tuberculate, v-shaped sensory patches present but not delimited by sharp carinae. Thorax:­­­ basal sulcus absent, lateral antebasal foveae minute or absent; median antebasal fovea present, often reduced to depression. Prosternum in front of coxae slightly convex, anteriorly with modified flattened setae absent or present; lateral procoxal foveae present. Mesoventrite with median shield; lateral mesoventral foveae present in large cavities filled with dense setae, meeting internally; lateral mesocoxal foveae absent; median mesoventral foveae present, paired, meeting internally; mesocoxae separated by extension of meso- and metaventrite. Metaventrite afoveate, variously modified; metacoxae separated by extension of ventrite I. Elytra with three basal foveae, single sutural fovea; single discal stria, sutural striae present. Abdomen:­­­ tergites ­­­ of usual form for tribe, otherwise unmodified; T2 without obvious basal foveae, lateral basal sulcus extending along width of ventrite, obscured by dense band of setae along posterior edge. Ventrite I covered in dense, shining setae; ventrite II variously modified with median depressions, sulci, or projections; ventrites otherwise unmodified.

Females: similar to males except eyes usually smaller, composed of fewer facets; secondary sexual modifications of the legs and ventrite 2 absent. ­­­

Comments.­­­ In NZ, Pselaphogenius is one of two genera (along with Pselaphaulax ) that have been found to comprise the majority of species previously described as Pselaphus on the mainland ( Chandler 2001; Owens et al. 2019). Since Chandler’s observations, three species have been transferred from Pselaphus to Pselaphogenius in the online database of Newton and Thayer (2003). Four new species were described from the fauna of Three Kings Islands ( Théry and Leschen 2013).

In NZ, species in the genus may be distinguished by the absence of an antebasal sulcus on the pronotum, the lateral antebasal foveae present or reduced, maxillary palpi IV elongate and widened in the distal 1/3-1/4 and with or without a v-shaped sensory patch not delimited by a carina, and the gular swelling hemispherical, typically as long as wide and not longer than wide. In this genus, the elytron typically possesses two basal foveae separated by a longitudinal carina, although some NZ species possess only one basal fovea and the carina may be reduced or absent. The postgenal area of this genus is typically nude, although some individuals have been found to bear flattened scale-like setae in this area. This variation in characters and divergence from some of the forms known from other faunas highlights the necessity of a revision of this genus in NZ and a revision of the global Pselaphini . Nevertheless, while other undescribed genera in the NZ fauna may superficially resemble Pselaphogenius , this combination of character states is unique and may be used to distinguish this genus from all others in the region.

Based on external characters, NZ species in the genus can be readily divided into two “species groups” which can consistently be distinguished by several characters ( Figs. 1–4 ), including: number of eye facets (few, about three in group 1, many, about fifteen in group 2); shape of gular mound (longer than wide, narrowed or rounded posteriorly and anteriorly in group 1, wider than long, broad anteriorly and posteriorly in group 2); form of maxillary palp IV (longer than head, swollen in distal ¼-1/ 5 in group 1, about equal to head length, swollen in distal ½ to 1/ 3 in group 2); and the shape of the metaventrite (depressed or flattened in group 1, flattened or produced into a tumosity in group 2). Future work on the Asian fauna may shed further light on these species group divisions, which may eventually warrant designation of subgeneric status. In the absence of these data, these should be considered designations to encompass morphological variation within this genus in New Zealand to aid identification.

Figures

FIGURES­­­1–2.­­­Pselaphogenius species groups 1 and 2 habitus photographs. Figure 1: Pselaphogenius parki, species group 1, a) habitus photograph, dorsal; b) habitus photograph, lateral. Figure 2: Pselaphogenius citimus, species group 2, a) habitus photograph, dorsal; b) habitus photograph, lateral.

FIGURES­­­3–4. Pselaphogenius species groups 1 and 2 ventral characters. Figure 3: Pselaphogenius sp., species group 1, a) head; b) meso- and metaventrite, ventrites 1 and 2. Figure 4: Pselaphogenius sp., species group 2, a) head; b) meso- and metaventrite, ventrites 1 and 2.