Two new species of Olecryptotendipes Zorina, 2007 from China (Diptera, Chironomidae)

Abstract Two new species, Olecryptotendipes exilis sp. n. and Olecryptotendipes melasmus sp. n. are described and illustrated as males and Chinese males of Olecryptotendipes lenzi are re-examined. A key to all known males of Olecryptotendipes is provided.


Introduction
Based on the morphology of the males in the Russian Far East, Cryptotendipes lenzi Zorina, 2001 andC. secundus Zorina, 2003 were described by Zorina (2001Zorina ( , 2003. Zorina (2007) collected the larvae and pupae of C. lenzi, and showed the two species should be placed in a new genus, named Olecryptotendipes Zorina, 2007. The type species is Cryptotendipes lenzi Zorina, 2001. To date, the genus only contains the two aforementioned species. Yan et al. (2005) recorded Cryptotendipes lenzi from Xinjiang Autonomous Region in China.
The males of Olecryptotendipes are characterized by Y-shaped anal tergite bands; posterior part of tergite IX elongated with setae; superior volsella with sclerotized part and membranous ridge, with dorsal and ventral setae, microtrichia absent or present ventrally and weak inferior volsella (Zorina 2007). For the diagnosis of pupa and larva, refer to Zorina (2007).
In the present paper, two new species are recorded. Prof. Ole Saether and Dr. M. Spies have checked the specimens. The two new species don't belong to the genera Cryptotendipes Lenz, 1941 andChernovskiia Saether, 1977 because of the presence of sclerotized superior volsella and lobate inferior volsella. In addition, the species of the genus Cryptotendipes lack an inferior volsella and the margin of the gonostylus is usually with an expansion. Species of the genus Chernovskiia are also without lobate inferior volsella, but with foot-shaped superior volsella, which also present in species of genera Paracladopelma Harnisch, 1923 andBeckidia Kieffer, 1913. The Y-shaped anal tergite bands (Figs 2,8), the shoulder-like margin of tergite IX (Figs 2,8), the sclerotized superior volsella (Figs 4, 10) and lobate inferior volsella (Figs 3,9) show them to belong to the genus Olecryptotendipes (O. Saether and M. Spies, pers. comm.). However, we have no specimens of larvae and pupae which are important to place the species properly.
The larvae of Olecryptotendipes inhabit sandy substrate in rivers (Zorina 2007). The Chinese specimens were collected from temperate zones and subtropical mountain areas in Palaearctic and Oriental China (Map 1).
Two new species, O. exilis sp. n. and O. melasmus sp. n., are described and illustrated based on material from China and a key to the males of Olecryptotendipes is provided.

Material and methods
The terminology follows Saether (1980) with the additions and corrections given by Saether (1990). The material examined was mounted on slides in Canada balsam following the procedure outlined by Saether (1969).
The type material and other material studied are housed in the College of Life Science, Department of Biology, Nankai University, Tianjin, China (BDN).

Amended generic diagnosis
Based on Zorina (2007) and the Chinese specimens, we amend the generic diagnosis. The following combination of characters will separate the genus Olecryptotendipes from other members of the Harnischia complex: Total length 2.7-3.6 mm; AR 1.83-2.24; frontal tubercles absent; anal tergite bands of Y-shaped; posterior margin of tergite IX with caudolateral shoulders; anal point parallel-sided or widest at about apical 1/3; superior volsella consisting of sclerotized part, dorsal and ventral setae present; inferior volsella with a weak blunt caudal projection, covered with microtrichia; gonostylus parallel-sided or slender to apex, inner margin without expansion.
Hypopygium (Figs 2−4). Tergite IX with weak lobes bearing 3−4 setae at each side of base of anal point. Laterosternite IX with 3 setae. Anal point 45−50 mm long, 5−6 mm wide, originating from caudal margin of anal tergite, completely parallel-side. Anal tergite bands Y-shaped. Phallapodeme 75−82 mm long. Transverse sternapodeme 56−60 mm long. Superior volsella (Fig. 4) slightly curved, with apical, partially sclerotized beak-like protrusion and slender spur-like posterolateral projection, bearing two long setae beside the beak-like protrusion, and covered with microtrichia in inner parts. Inferior volsella with a moderately blunt caudal projection, covered with microtrichia, and not reaching beyond margin of anal tergite. Etymology. From Latin exilis, slender, in reference to the slender posterolateral projections of superior volsella.
Distribution. The species was collected in a subtropical mountain area in Hainan province in Oriental China.  (2001) and Yan et al. (2005), the species is easily distinguished from the other species of the genus by having shoulder-like posterior margin of tergite IX and digitiform superior volsella with a longitudinal keel.
Distribution. This species is distributed in the Russian Far East and northwestern China.
Coloration. Thorax (Fig. 5) yellowish brown, with median black brown vittae. Femur of front leg yellowish green with distal parts dark brown, tibia dark brown except for median parts yellowish green, tarsi dark brown with basal 3/4 of ta 1 yellowish green; femora and tibia of mid and hind legs yellowish green with distal parts of femora and basal parts of tibia dark brown, ta 1 to ta 5 lightly brown (Fig. 6). Abdomen yellowish green to brown, with tergite I-V yellowish green, tergite VI-VIII and hypopygium yellowish brown.
The gonostylus of O. lenzi and O. secundus nearly parallelsided, but which is slender to apex of the two new species. The species O. secundus only with sclerotized superior volsella and without membranous ridges, it seems to O. exilis sp. n. with sclerotized beak-like protrusion. From the above, the generic characters of Olecryptotendipes should be emended as follows: "Posterior margin of tergite IX with caudolateral shoulders; gonostylus parallel-sided or slender to apex; superior volsella consisting of sclerotized part, dorsal and ventral setae present."