Cephennomicrus cornutus (Scott)

Jałoszyński, Paweł, 2019, Review of Cephennomicrus and Pomphopsilla of the Seychelles (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 4568 (2), pp. 357-371 : 360

Cephennomicrus cornutus (Scott)

( Figs 2 , 9 , 16–17, 28–29, 39)

Neseuthia cornuta Scott, 1922: 205 , pl. 19, fig. 8, 8a.

Cephennomicrus cornutus (Scott) ; Jałoszyński, 2008: 33.

Type material. Holotype (labels in Fig. 39 ): ♂, disarticulated and mounted on thick cardboard bearing male symbol and number "104" handwritten in black ink, with seven labels: " Percy Sladen / Trust Exped. / Brit.Mus. / 1926-246" [white, printed], "Mahe, '08-9 / Seychelles Exp." [white, printed], " Neseuthia / cornuta / TYPE. H.Scott / TYPE " [white, handwritten, with " TYPE " printed on a blue card and glued onto the white label], " cornutus Scott / Cl. Besuchet / dét. X 1957 " [white, printed and handwritten], "Figured specimen" [red, printed], "Type" [white circle with red margin, printed], and " CEPHENNOMICRUS / cornutus / (Scott) / det. P. JAŁOSZYŃSKI, 2019" [white, printed] ( NHM).

Revised diagnosis. BL ~ 0.90 mm; frontal impression in male U-shaped with broadly rounded posterior margin, areas flanking impression strongly elevated, vertex with a pair of large impressions; aedeagus with moderately slender ventral apical plate and pointed apex, flagellum in ventral view with equally large proximal and distal loops.

Redescription. The only known specimen is disarticulated ( Fig. 2 ), but it seems to be moderately stout and strongly convex. Pigmentation umber brown; setae on head, pronotum and elytra very short but well-visible. BL 0.88 mm.

Head ( Fig. 9 ) broadest at large, strongly convex and coarsely faceted eyes, HL 0.13 mm, HW 0.24 mm; frons with distinct U-shaped impression with broadly rounded posterior margin, which is strongly concave and more narrowly rounded at middle than on sides, impression posteriorly and posterolaterally delimited by an M-shaped area which is very strongly elevated and bears a pair of barely discernible porous fields near middle, vertex confluent with frons, with a pair of large but shallow and diffuse impressions; supraantennal tubercles weakly elevated. Punctures on frontal impression distinct, on sides of frons and vertex and on posterior portion of vertex indistinct, moderately dense, very small; setae on frontal impression moderately dense, short and recumbent to slightly suberect, setae on sides of frons and vertex and along posterior margin of vertex sparse, short and recumbent, impressions on vertex and M-shaped frontal elevation asetose. Antennae slender, with indistinctly delimited trimerous club, AnL 0.40 mm, antennomeres I–II strongly elongate, III about as long as broad, IV–VII each slightly elongate, VIII–X each about as long as broad, XI about as long as IX–X combined, about 1.6 × as long as broad.

Pronotum subtrapezoidal, broadest near anterior fourth; PL 0.25 mm, PW 0.33 mm; anterior and posterior margins weakly convex, sides rounded in anterior third and barely noticeably sinuate in posterior third; anterior corners broadly rounded, posterior corners strongly obtuse-angled and blunt; base with two lateral pairs of small but distinct pits, inner pair connected by a shallow transverse groove, additionally with a very small, barely noticeable median pit; lateral pronotal carinae not serrate. Punctures on pronotal disc dense but superficial and diffuse; setae short, moderately dense, recumbent.

Elytra oval, broadest site not possible to determine; EL 0.50 mm, EW 0.43 mm, EI 1.18; humeral calli distinct. Punctures on elytra similar to those on pronotum but deeper and elytral surface appears finely shagreened; setae short, moderately dense, recumbent.

Legs moderately long and slender, unmodified.

Aedeagus (Figs 16–17) stout; AeL 0.16 mm; median lobe in ventral view with subtriangular, moderately elongate apical plate; flagellum (Figs 28–29) in ventral view with proximal and submedian loops of similar diameter; each paramere with thick apical and thin subapical seta.

Female. Unknown.

Distribution. Seychelles, Mahé Island.

Remarks. This species was described on the basis of only one specimen, disarticulated already at the time of description ( Scott 1922). The head modification in males of C. cornutus is very similar to that of C. typicus , but the frontal impression between antennae is narrower, with a deeper posterior concavity, and the impression is posterolaterally flanked by a pair of subtriangular convexities which are distinctly more elevated than the same area in C. typicus . The flagella of these species are also similar, but in C. cornutus the ventral apical plate of the median lobe is distinctly less elongate and not abruptly delimited.

Figures

FIGURES 1–7. Habitus of Cephennomicrus cordithorax (1), C. cornutus (2), C. minor (3), C. perexiguus (4), C. politus (5), C. typicus (6), and Pomphopsilla crenata (7).

FIGURES 8–13. Head of males in dorsal (8‾12) and anterodorsal (13) views. Cephennomicrus cordithorax (8), C. cornutus (9), C. minor (10), C. politus (11), and C. typicus (12‾13).

FIGURES 38–44. Historical (Scott's and Besuchet's) set of labels of holotypes (38, 39, 42) and lectotypes (40, 41, 43, 44). Neseuthia cordithorax (38), N. cornuta (39), N. minor (40), N. perexigua (41), N. polita (42), N. typica (43), and N. crenata (44).