Nala alenae, Kočárek, 2006

Kočárek, Petr, 2006, A new species of Nala (Dermaptera: Labiduridae) from Cambodia, Acta Entomologica Musei Nationalis Pragae 46, pp. 1-6 : 2-4

Nala alenae sp. nov.

( Figs. 1-5 )

Type locality. Cambodia, Siem Reap, Angkor Wat temple.

Type material. HOLOTYPE: ♁, ‘NW CAMBODIA, Siem Reap env. / Angkor Wat temple; 40 m a.s.l. / 13°24′42.23″N, 103°51′49.84″E / P. Kočárek leg.; 7.-11.ix.2002 ’ ( MMBC) ; Paratypes: 5 ♀♀, same label data as holotype (one specimen MMBC, one specimen ZSMG, three specimens PKOC).

Description of male. Body dark reddish brown; head entirely black, antennae dark brown; pronotum and elytra reddish brown to brown with paler sides; legs yellowish brown, femora and tibiae with dark brown basal parts; ultimate abdominal tergite dark brown; forceps dark brown to reddish brown at apex. Cuticle punctured, dull, pubescent; tegmina rugose. Length without forceps 7.3 mm, length of forceps 1.3 mm.

Head globose, as wide as long, postfrontal and coronal sutures indistinct, posterior margin straight, with short and dense pubescence. Eyes small, less than 0.5 times as long as length of head behind eyes. Antennae of holotype male with 17 antennomeres (incomplete); antennomere 1 short, narrowed basally, widened terminally, half as long as the distance between antennal bases; antennomere 2 transverse, only little longer than wide; antennomere 3 longer than antennomere 4. Antennomeres 1-3 cylindrical, antennomeres 4-17 conical.

Pronotum transverse, widened posteriorly.Anterior margin straight, posterior margin broadly rounded. Pronotal disc rugose, with smoother anterior half, median suture distinct. Tegmina as long as pronotum, rugose, parallel-sided; each with well marked lateral longitudinal ridge, tegminal disc flattened; posterior margin convex, with broadly rounded interior angle. Wings entirely concealed under tegmina, reduced to very small, longitudinally oriented flaps (0.25 mm long, 0.05 mm wide).

Abdomen convex, somewhat widened posteriorly, densely punctured, shortly pubescent with long setae along hind margin of each tergite except the ultimate one, lateral glandular folds invisible. Penultimate sternite punctulate, sides scarcely concave, hind margin obtusely produced in middle ( Fig. 4 ). Ultimate tergite transverse, slightly depressed medially, with invisible median line, little oblique laterally, hind margin straight with protuberance at each base of forceps branch.

Pygidium invisible in dorsal view. Forceps ( Figs. 1, 2 ) with branches remote, gradually incurved, each tapering to pointed and gently hooked apex, triangular in basal half and dorsoventrally flattened in distal half. Inner and upper margins of forceps serrated in proximal third, middle of forceps with distinct tapering, distal third widened into flat protuberance.

Genitalia ( Fig. 5 ) typical for the genus Nala , with parameres a little over six times longer than broad, narrowed apically, tip acuminate; genital lobes widening to the apex, with straight apical part; virga tubular with undulated central part and sclerotized basal vesicles.

Description of female. Body length without forceps 6.8-7.9 mm, length of forceps 1.4-1.5 mm. Body colouration similar to holotype male, abdomen wider in middle part. Ultimate tergite with tapering sides, hind margin sinuate in middle. Forceps straight, simple, tapering, inner margin serrated, triangular in basal third, the rest dorsoventrally flattened ( Fig. 3 ).

Differential diagnosis. Nala alenae sp. nov. and N. lividipes (Dufour, 1829) are the two smallest species of this genus known from South-East Asia, with total body length including forceps ranging between 7.5-8.5 mm. Nala alenae sp. nov. can be distinguished from N. lividipes by the very short tegmina, which are only as long as the pronotum, and the wings entirely concealed under the tegmina. Nala timorensis Brindle, 1967 , and N. basalis Bey-Bienko, 1970, also have concealed wings; however, winged specimens were described for the latter species ( SRIVASTAVA 2003). The forceps of N. alenae sp. nov. are unusually short in males, being only as long as the width of the ultimate tergite. Nala alenae sp. nov. is further characterized by the entirely black head. Although the females of Nala are morphologically very similar and cannot be reliably identified, the females of N. alenae sp. nov. are fairly easily recognized by their exceptionally short tegmina and the absence of wings (see above). The males of South-East Asia Nala can be separated by the key provided below.

Etymology. The new species is dedicated to my wife Alena, who helped me collect the type specimens.

Bionomics. Unknown. Type specimens have been collected in the surroundings of Angkor Wat temples in a stony habitat surrounded by lowland rain forest. The earwigs were observed to run on stony ground in late afternoon.

Distribution. Cambodia.

Comments. Nala alanae sp. nov. is a very characteristic species, differing from all other Asian species in the shape of the reduced tegmina with well marked longitudinal ridges (see Fig. 1 ). Other Nala species with similar tegmina, reduced wings and short stout forceps are known only from Central and South Africa ( N. caprai Menozzi, 1929 , N. figinii Burr, 1908 , N. intermedia Menozzi, 1937 , N. saegeri Brindle, 1968 , N. rossii Vigna Taglianti, 1994 , and N. mendesi Bivar de Sousa, 1999 ). Nala alenae sp. nov. is the only known Asian representative with a noticeable morphological similarity to this African group of species, which may indicate some affinity to this group. From the known African species, N. alenae sp. nov. differs in the characteristic shape of male forceps.

Figures

Figs 1-5. Nala alenae sp. nov. 1 – habitus of male, dorsal view; 2 – right branch of male forceps, dorsal view; 3 – right branch of female forceps, dorsal view; 4 – subgenital plate of male, dorsal view; 5 – male genitalia, dorsal view. Scale bar = 1 mm.