Oxylakis singaporensis, Ingrisch & Tan, 2012

Ingrisch, Sigfrid & Tan, Ming Kai, 2012, New Taxa Of Agraeciini (Orthoptera: Tettigoniidae: Conocephalinae) From Singapore And Malaysia With A Review Of The Genus Jambiliara, Raffles Bulletin of Zoology 60 (1), pp. 137-155 : 142-145

Oxylakis singaporensis , new species

( Figs. 4 , 5 )

Material examined. — Holotype: male ( BMNH, B.M. 1959–149) Singapore: Tenga, R.A.F. Station [R.S.A.F. Tengah Airbase], coll. C. Clayton, Mar.1958 . Paratype: Singapore, 1 female ( BMNH), coll. H.N. Ridley , 1901.

Diagnosis. — The new species is close to O. punctipennis Redtenbacher, 1891 , O. sumatranus Ingrisch, 1891 and O. karnyi Ingrisch, 1891 . The key in Ingrisch (1998) runs out near the latter two species. It differs by the male cerci and the titillators. The cerci are regularly curved mediad and only slightly narrowing towards the apex as in O. punctipennis , but have the apex armed with a spinule and the basal appendages deviating in a rectangular way, the cerci are a little twisted in apical area as in O. sumatranus , but the latter does not have an apical spinule and the basal appendages almost rectangularly deviating after having arisen from a common trunk; in O. karnyi they deviate in an acute angle. The male titillators, a pair of hyaline plates that obviously represent the apical parts while the basal parts are reduced, resemble those of O. karnyi . They differ by their shorter and wider shape, being arched and with a short medio-apical lobe. In O. sumatranus the titillators are reduced to the medial area, while in O. punctipennis the phallus is without sclerotised structures. The female subgenital plate with a slightly bilobate central plate with moderate apical excisions and auricular membranous lateral lobes also resembles the situation in O. punctipennis , O. sumatranus and O. karnyi . It differs from all three by the strong medial furrow and a distinct angular projection at the bottom of the apical excision that is very faint or hardly observable in O. punctipennis and O. sumatranus , absent in O. karnyi .

Description. — Agrees in general characters with the generic description given in Ingrisch (1998). Fastigium verticis conical, apex obtuse, furrowed above. Frons shining with few impressed dots, genae rugose ( Fig. 4B ). Pronotum rugose, anterior margin broadly rounded but faintly subtruncate in middle ( Fig. 4C ), posterior margin truncate; anterior-ventral angle obtusely projecting; transverse sulcus faintly indicated on disc. Prosternal spines short. Tegmen surpassing stretched hind legs ( Fig. 4A ). Mesocoxa with rounded swelling at ventro-internal margin rather large. Knee lobes of pro- and mesofemur obtuse on both sides; of postfemur obtuse on external, obtuse or spinose on internal side. Femora with the following number of spines on ventral margins: profemur 2–3 external, 4 internal; mesofemur 4–5 external, 0 internal; postfemur 5–7 external, 0 internal.

Male: Stridulatory file with teeth extremely dense; with about 176 teeth at 1.4 mm, equating 126 teeth per mm; in middle with about 68 teeth per 0.5 mm ( Fig. 4G ). Tenth abdominal tergite with apical area strongly setose; apical margin weakly bilobate ( Fig. 4D ). Epiproct rounded. Cerci long, substraight, at apex little twisted, external surface rounded, internal surface furrowed; apex with a minute spinule at tip ( Fig. 4D ); at very base with two internal projections on a common trunk, one pointing medio-apicad, the other medio-ventrad ( Fig. 5B ). Subgenital plate with apex subtruncate, little concave; styli short ( Fig. 5A ). Titillators hyaline, reduced to the apical parts, forming a pair of convex hyaline plates with the medioapical angle little obtusely projecting ( Fig. 5C ).

Female: Cerci long-conical, slightly curved, apex pointing ( Fig. 5E ). Subgenital plate transverse, with a strong medial furrow; apical margin bilobate, broadly excised between both lobes and with a small angular projection in bottom of excision; on each side with a baso-lateral, more or less membranous, auricular projection ( Fig. 5D ). Ovipositor compressed-ovoid, with substraight basal and ovoid apical part, margins regularly curved and smooth ( Fig. 5E ).

Colouration: Brownish testaceous. Tegmen with darker spots; in male at end of stridulatory field with a dark brown spot. Ovipositor with marginal area reddish-brown, becoming very dark towards apex, base and central areas yellowishbrown.

Measurements (1 male, 1 female): Body with wings: male 32; body without wings: male 15, female 21; pronotum: male 4.8, female 5.3; tegmen: male 28, female 32; hind femur: male 9, female 11; hind wing: female 32; ovipositor: female 10.5 mm.

Etymology. — Named after the type locality, Singapore.

Figures

Fig. 4. Oxylakis singaporensis n. sp. male holotype: A, habitus lateral view; B, face; C, head in dorsal view; D, abdominal apex in oblique dorsal view; E, stridulatory area of left tegmen; F, do. of right tegmen; G, stridulatory file on underside of left tegmen. Scale bars = 1 mm, only in A = 10 mm. (Photographs by: S. Ingrisch).

Fig. 5. Oxylakis singaporensis n. sp. details of male holotype (A–C) and female paratype (D, E): A, subgenital plate and cerci in ventral view; B, base of right cercus in oblique internal view and part of subgenital plate with stylus (note that the fold in the dorsal process of the cercus is due to distortion during drying); C, titillators (thick lines) and soft part of phallus (thin lines) in dorsal view; D, subgenital plate in ventral view; E, ovipositor. Scale bars = 1 mm (E not to scale). Abbreviations: ce, cercus; ov, base of ovipositor; ph, phallus; pr, baso-internal projections; sg, subgenital plate; st, stylus; ti, titillator. (Photographs and illustration by: S. Ingrisch).