Kenocoelus Broun, 1911

Nomura, Shûhei & Leschen, Richard A. B., 2015, Myrmecophilous Pselaphinae (Coleoptera: Staphylinidae) from New Zealand, The Coleopterists Bulletin 69 (1), pp. 121-152 : 121-152

Kenocoelus Broun, 1911

( Figs. 1–3 , 23A )

Kenocoelus Broun, 1911: 700 . Type species: Kenocoelus dimorphus Broun, 1911: 701 , by monotypy.

Diagnosis. Body small (1.46–1.76 mm), elongate, nearly smooth on dorsal surface. Head about as wide as prothorax, wider than long, nearly trapezoidal, surface of frons more or less even, vertex weakly convex with minute vertexal fovea (visible in dissections); posterior constriction not notched and lacking lateral fovea; postgenae narrow, rounded; venter lacking beard. Eyes small, ovoid, and visible in dorsal view for all species ( Fig. 1 ). Antennae short with insertions hidden in dorsal view, slender; antenomere I very short, about half length of II, subcylindrical; antennal tubercles absent. Pronotum slightly longer than wide, rounded laterally, with pair of lateral foveae at basal 1/3 and shallow transverse depression at basal 1/3 ( Fig. 1 ). Elytra slightly longer than pronotum with flat dorsal surface, each elytron with 2 basal foveae and complete adsutural sulcus ( Fig. 1 ). Prosternum without lateral and median longitudinal carinae. Ventral foveae simple, those present as follows: gula (head); lateral procoxal (prosternum); lateral mesoventral and well-developed pore adjacent to mesoventral carinae midlength between procoxal rests, mesocoxal cavity, lateral mesocoxal (mesoventrite); lateral metaventral (metaventrite); mediobasal and basolateral (abdominal sternite III). Legs short, slender; 1 tarsal claw present.

Abdomen slightly longer than elytra, with tergites subequal in length, flattened on dorsal side ( Fig. 1 ), sternite III very short, large excavations on sternites IV and V in male ( Fig. 2 ); segments IV–VI each transverse, with pair of narrow and parallel-sided paratergites. Male genitalia slender; median lobe thickened near middle ( Fig. 3 J-L).

Remarks. This genus is separable from the other genera of Trichonychini by having a smallsized and nearly smooth body form, a very short first antennal segment, and the pronotum lacking sulci. It is also distinct by having large concavities on the ventral side of abdomen in the male. The form of the male genitalia is similar to those of other Panaphantina in New Zealand (e.g., Zeadalmodes new genus, Myrmecoplectus new genus, Euplectopsis Raffray , Plectomorphus Raffray ).

Nomura and Leschen (2006) placed Kenocoelus in Panaphantina , though Chandler (2001) argues for a sister relationship of this genus with the South Australian Plectostenus Lea , placed in Trichonychina based on the following characters of the head: “presence of prominent ventrolateral tubercles, convex vertex lacking a sulcus, nude vertexal foveae, and indistinct antennal tubercles.” Kenocoelus differs from Plectostenus by the lack of an antennal club, having a weak antebasal sulcus, and reduced ventral foveature.

Figures

Fig. 1. Kenocoelus species, habitus. A) K. dimorphus, male, B) K. mikonuiensis, male, C) K. johni, male, D) K. dimorphus, female, E) K. mikonuiensis, female, F) K. johni, female. Scale bar = 1 mm.

Fig. 2. Kenocoelus species. A) K. dimorphus, ventral view, B) K. mikonuiensis, ventral view, C) K. johni, ventral view, D) K. dimorphus, abdominal sternites IV–V, ventral view, E) K. mikonuiensis, abdominal sternites IV–V, ventral view, F) K. johni, abdominal sternites IV–V, ventral view, G and J) K. dimorphus, left concavities on abdominal sternites IV–V, H and K) K. mikonuiensis, left concavities on abdominal sternites IV–V, I and L) K. johni, left concavities on abdominal sternites IV–V.

Fig. 3. Kenocoelus species. A) K. dimorphus, abdominal tergite VIII, B) K. mikonuiensis, abdominal tergite VIII, C) K. johni, abdominal tergite VIII, D) K. dimorphus, sternite VIII, E) K. mikonuiensis, sternite VIII, F) K. johni, sternite VIII, G) K. dimorphus, abdominal segment IX, H) K. mikonuiensis, abdominal segment IX, I) K. johni, abdominal segment IX, J) K. dimorphus, male genitalia, K) K. mikonuiensis, male genitalia, L) K. johni, male genitalia. Scale = 0.1 mm.

Fig. 23. Type specimens and their original labels. A) Kenocoelus dimorphus, B) “Dalma” gigantea, C) Neosampa granulata.