Drusilla ashei Eldredge

Eldredge, Taro, 2012, Review of the Nearctic species of Drusilla Leach (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 3300, pp. 45-54 : 50-51

3. Drusilla ashei Eldredge , new species

( Figs. 2 , 12–15 , 24–25 )

Type material. Holotype: U.S.A.: 3, “ NORTH CAROLINA/Rockingham Co./Reidsville, 5–13 May/1979, J.S.Ashe/ex., pan traps” ( SEMC). Paratypes (3 ƤƤ, 43): U.S.A.: same as holotype label (23; SEMC); “Rockingham Co., Reids-/ville, Apr. 29-May 3, 1970 /J. Ashe, ex: pan trap” (3; SEMC); “Rockingham Co., N.C./Reidsville/ VIII-12-1973 /JS, Ashe//James S. Ashe Collection” (Ƥ; SEMC); “Rockingham Co., N.C./Reidsville/ VIII-14- 1973 /J.S. Ashe//on and under Boletus sp.//James S. Ashe Collection” (2 ƤƤ, 3 [additional label reads: “will not key out/in Seevers (1978) /but seems closest/to Drusilla Leach ”]; SEMC).

Diagnosis. Drusilla ashei most closely resembles D. nearctica , but can be confidently separated by the following male characters: shape of the median lobe ( Figs. 12–13 ); distal apodeme eight times its width ( Fig. 12 ); costal morphology of median lobe parameral surface ( Fig. 13 ); paramere with velum not obscuring apical lobe in outer lateral view ( Fig. 14 ); chaetotaxy of parameral apical lobe ( Fig. 15 ).

Description. Drusilla ashei is externally indistinguishable from D. nearctica in many respects; only those characters that differ have been included in the description.

Body ( Fig. 2 ) length on average 3.2 mm (3.05–3.39 mm, n = 8). Body color with head, pronotum, elytra and most of abdomen dark brown, sometimes with elytra and tergites II–IV brown; tergites V–VIII piceous; legs usually concolorous with most of body and dark brown, sometimes yellowish-brown.

Head subcircular (HW = 0.47 mm, 0.45–0.48 mm; HL = 0.48 mm, 0.45–0.50 mm; HW/HL = 0.98, 0.94–1.07); eyes small and occupying approximately a third of head length (OL = 0.15, 0.14–0.17 mm; OL/HL = 0.32, 0.27– 0.34).

Pronotum slightly transverse (PW = 0.55 mm, 0.54–0.57 mm; PL = 0.52 mm, 0.50–0.53 mm; PW/PL = 1.07, 1.06–1.09).

Elytra, together, transverse (EW = 0.59, 0.57–0.60 mm; EL = 0.44, 0.42–0.45 mm; EW/EL = 1.35, 1.31–1.38).

Males with median lobe elliptical in lateral view ( Fig. 12 ) and limuloid in parameral view ( Fig. 13 ); apical lobe of median lobe long, extending anteriorly in a nearly horizontal fashion, with apex abruptly diverting paramerally; athetine bridge incomplete at aparameral surface, with distal apodeme eight times its width; foramen situated slightly posterior of middle; proximal costa short, occupying approximately two thirds of posterior surface posterior of foramen; median costa extending to apical lobe; arcuate costa running parallel with median costa basally but never touching, broadly diverging until reaching apical lobe, distally recurving back to foramen; paramere ( Fig. 14 ) with length greater than two times its width, velum, in outer lateral view, not obscuring apical lobe; parameral apical lobe ( Fig. 15 ) in inner lateral view with four setulae: setulae a and d on inner surface, b and c on outer surface; setula a longest; b, c and d subequal in length.

Etymology. In honor of the only collector of this species, the late Dr. J.S. Ashe – noun in the genitive case.

Figures

FIGURES 1 – 3. Holotypes of Drusilla. Dorsal habitus: 1) D. nearctica; 2) D. ashei. 3) D. nearctica lateral view of head and thorax.

FIGURES 12 – 19. Male genitalia of Drusilla ashei (12 – 15) and D. nearctica (16 – 19). 12, 16) aedeagus, lateral; 13, 17) aedeagus, parameral; 14, 18) paramere, outer lateral; 15, 19) apex of apical lobe of paramere, inner lateral. Scale bars (0.1 mm): I = 12 – 14, 16 – 18; II = 15, 19.

FIGURES 20 – 25. Details of Drusilla nearctica (20 – 23) and D. ashei (24 – 25). 20) tergite VIII; 21) sternite VIII; 22) female genital segments (tergites IX and X), showing genital plate and spermathecal duct, dorsal; 23) spermatheca; 24) male genital segments (sternite IX and tergites IX and X), dorsal; 25) detail of sternite IX, ventral. Scale bars (0.1 mm): I = 20 – 22, 24 – 25.