Eremobittacus spinulatus Byers

Villagomez, Fernando, Contreras-Ramos, Atilano & Marquez-Lopez, Yesenia, 2015, Rediscovery of Eremobittacusspinulatus Byers (Mecoptera, Bittacidae) in Mexico, with description of the female and comments on sexual dimorphism and potential mimicry, ZooKeys 539, pp. 111-117 : 112

Taxon classification Animalia Mecoptera Bittacidae

Eremobittacus spinulatus Byers Figs 1-6

Description.

Male (Fig. 1; n = 3, pinned). Forewing length 13.0-13.3 (13.2); forewing width 2.7-3.2 (3.0); antenna length 5.9-6.6 (6.2); hind femur length 6.0-6.4 (6.2); hind femur width 1.2-1.3 (1.25). Original description in Byers (1997).

Female (Fig. 2; n = 3, pinned). Forewing length 12.2-13.1(12.7); forewing width 3.0; antennae length 6.0-6.5 (6.2); hind femur length 5.1-5.4 (5.2); hind femur width 0.63-0.68 (0.65). General appearance similar to male, particularly in coloration and general body proportions, however hind femora appear narrower than in male (Fig. 1).

Abdomen (Fig. 4). Terga and pleura dark brown to entirely black, with dark short setae; VIII sternite fused with the subgenital plate, dorsally separated from tergites VIII and IX by an incision; stigma of segment VIII above a concavity in the sternite; subgenital plate with about 30 conspicuous dark spine-like setae, with an oblique plate connected with the 9th tergite; short non segmented cerci reaching about half the length of supra anal plate (or XI tergite).

Legs (Fig. 2). First and second pair of legs pale brown, with darkened areas at joints; hind legs modified, basal three fourths of femur blackish brown, distal fourth pale brown, slightly widened at median; widening about half that in males (Fig. 1), conveying sexual dimorphism; also, femur spine-like setae less developed than in males.

Intraspecific variation. In the original description by Byers (1997, fig. 11), the male epiandric appendix is illustrated with a slight median protuberance, dorsally; however, the protuberance is inconspicuous in the specimens examined (Fig. 3). Furthermore, a ventral view of the basistilum (bs) was not included in the original description (herein shown in Fig. 5) and its setation was illustrated only partially (herein shown in Figs 3, 5 and 6). One of the main diagnostic traits proposed for this species is a pattern of three transverse veins surrounded by a darkened region in both fore and hindwing; conversely, this feature was found variable, as in some specimens the pattern is diffuse or dimly visible. The wing longitudinal veins also display a certain degree of variation, for example, in number of veins between R2 and R3, R3 and R4, and between R5 and M1, as well as in number of Pcv veins under the pterostigma.

Material examined.

Mexico, Oaxaca, 26 km SE Cuicatlán, 17°37'02.09"N, 96°55'23.52"W, 1080 m, 16-X-1998, M.A. Morales, 1♀; same data except E. Ramirez collector, 1♀; Oaxaca, 25 km SE Cuicatlán, 17°37'16.38"N, 96°55'10.02"W, 1000 m, 17-X-1998, F. Noguera, 1♀; Oaxaca, 26 km SSE Cuicatlán, 17°36'9.88"N, 96°55'39.2"W, 1080 m, 16-X-1998, E. Ramírez, 1♂; same data except M.A. Morales, 1♂; same data except 18-X1998, 1♂.