Ngirhaphium chutamasae, Samoh, Abdulloh, Boonrotpong, Singtoe & Grootaert, Patrick, 2015

Samoh, Abdulloh, Boonrotpong, Singtoe & Grootaert, Patrick, 2015, Ngirhaphium Evenhuis & Grootaert from southern Thailand (Diptera: Dolichopodidae) with the description of a new species, Zootaxa 3946 (1), pp. 125-132 : 126-130

Ngirhaphium chutamasae sp. nov.

( Figs 1–6 )

Diagnosis. A large species differing from the other Ngirhaphium species mainly in the structure of the male genitalia. Cercus in lateral view slightly shorter than dorsal surstylus. Cercus brown, tip pointed bearing a single yellow bristle. Dorsal surstylus brown, bordered with short, stout yellow bristles. Outer branch of apical fork on the fore tarsomere 4 slightly longer than inner branch. M1+2 with a short stub on apical bend.

Material examined. HOLOTYPE ♂, labelled: “ THAILAND: Satun prov., Tammalang (6°32'21.05"N, 100°04'9.42"E), 3.x.2014 (reg. 34030, leg. P. Grootaert)” ( PSU); PARATYPE: 1 ♂, Tammalang (6°32'21.05"N, 100°04'9.42"E), 6.viii.2014 (leg. A. Samoh) ( RBINS).

Etymology. The species is dedicated to Associate Professor Dr. Chutamas Satasook, director of the Princess Maha Chakri Sirindhon Natural History Museum of the Prince of Songkhla University, Hat Yai as a token for her dynamic support of our research.

Description. Male. Length body: 7 mm; wing: 5.6 mm. Head. Frons shining metallic green (not dusted). Face greenish brown in ground-colour; apex of face and clypeus yellowish brown in ground-colour, wide, nearly as wide as front of frons, parallel-sided, grey dusted with very short clypeus (less than 0.1 length of face). Eyes pass beyond border of face; eyes densely set with white hairs. Ocellar callus globular protruding from frons with 2 very long ocellars, directed backward, divergent. Vertical bristles long, half as long as ocellars, rather anteriad on frons at level of ocellar callus, close to eye border, long, black, directed forward and cruciate. Pair of long black postverticals directed backward and crossing. Postoculars above strong, black in single row, below white and mixed with very long white hairs below mouth; postcranium greenish in ground-colour but grey dusted. Palpus long, strap-shaped, yellowish with few short black hairs, no bristles. Labella brown with black hairs. Antenna very long, completely black. First segment long, 3X as long as second segment; second segment short, apically with crown of short black bristles. Third segment very long strap-shaped, laterally flattened, about 6X as long as width at base. Arista apical, apical article longer than basal article, gradually tapered towards tip. Length of scape: 0.52; pedicel: 0.13; postpedicel: 0.95; basal aristal article: 0.34; apical aristal article: 0.4 (in mm). Thorax and scutellum dark metallic green in ground-colour (bluish when seen from in front), covered with fine grey dusting. All hairs and bristles black. Pleura more densely grey dusted than mesonotum. Acrostichals biseriate, about 7 pairs, rows widening slightly behind. Presutural dorsocentrals multiseriate; 6 postsutural dorsocentrals: 4 short and 2 long prescutellars; 1 pair of strong scutellars. One long humeral with shorter bristle in front; 1 strong posthumeral, 2 strong notopleurals, 1 postsutural, 1 supraalar, 1 very strong postalar. Propleural bristles black, 6 short upper and 2 longer lower propleural bristles (lower one twice as long as upper). Legs ( Fig. 1 ) yellow, all bristles black. All coxae greenish black in ground-colour, covered with fine greyish dusting. All trochanters brown. Tip of hind tibia annulated brown at tip. All tarsi yellowish, becoming darker towards tip. Apical tarsomeres completely black. Fore leg. Coxa with short black bristles. Fore femur slightly swollen on basal half; row of minute posteroventrals in apical half. Short preapical posterior bristle and 1 stronger anterior preapical bristle directed forward. Fore tibia with 4 strong ad, 4 strong pd and crown of 4 apicals. All tarsal segments densely set with black hairs and short black bristles. Tarsomere 4 with dorsal asymmetrical fork, extended over tarsomere 5; fork about 1.5X length of tarsomere; outer branch of fork slightly longer than inner branch, tips pointed ( Fig. 1 , inset). Terminal segment with pair of long normal claws and thicker claw-like structure beneath posterior claw. Two well-developed pulvilli and empodium present. Length of femur, tibia and tarsal segments (in mm): 2: 1.96: 0.98: 0.56: 0.28: 0.28: 0.28. Mid leg. Coxa with short bristles anteriorly; no exterior bristle. Mid femur as wide as fore femur; ventrally with inconspicuous bristles; 1 strong anterior preapical and 2 tiny posterior preapicals. Tibia with 6 ad, 6 pd (might be considered as dorsal), 8 longer av and crown of long apicals. Tarsomeres 1–4 ventrally at tip with pair of short spine-like bristles as well as comb of shorter black spinules. Apical tarsomere dorsally thickly set with long black squamiform bristles. Length of femur, tibia and tarsal segments (in mm): 2: 3.08: 1.68: 0.84: 0.77: 0.35: 0.42. Hind leg. Coxa bare. Hind femur thicker than mid femur, as wide as fore femur; ventrally almost bare; 1 strong anterior preapical, 1 fine posterior preapical. Tibia stronger bristled than mid tibia with 7 long av, 7 ad, 7 pd and crown of long apicals. Tarsomeres 1–4 ventrally at tip with pair of short spine-like bristles as well as comb of shorter black spinules. Length of femur, tibia and tarsal segments (in mm): 2: 3.78: 1.68: 0.98: 0.77: 0.42: 0.35. Wing mostly tinged brownish, but anteriorly between costa and R4+5 with yellowish brownish tinge. Tp brown seamed. Veins dark brown, yellowish at base. M1+2 sharply bent upwards and ending in costa closely near tip of R4+5. Tp straight, about as long as apical part of M3+4. Anal vein reaching wing border. Halter with white knob. Squama white with long white cilia. Abdomen shiny dark metallic green; tips and sides of tergites with greyish dusting. Sternites greyish dusted. Tergites densely set with quite long black bristles; hind-marginal bristles slightly longer than other bristles. Only tergite 5 with very long marginal bristles. Sternites with very short hairs except for longer marginals on sternite 4. Genital capsule black. Cercus brown, slightly shorter than dorsal surstylus ( Fig. 3 ). Ventrally at base with black sclerotisation. Both cerci fused for almost entire length, only tips free ( Fig. 4 ). Tip of cercus pointed, with single yellow apical bristle, dorsally set with long black bristles. Dorsal surstyli brown, much enlarged, forming clasper transverse on cercus, bordered with short, stout yellow bristles, shorter than surstylus is wide ( Fig. 3 ). Ventrally with dark spur-like apex ( Fig. 5 ). Ventral and dorsal surstyli not fused. Ventral surstylus yellowish, large, rounded ( Fig. 2 ); tip with short hair-like bristles; inner carina running parallel to dorsal border. Hypandrium dorsally with large rounded black protuberance set with spinules ( Fig. 3 ). Female. Indistinguishable from females of N. sivasothii (see Remarks section).

Remarks. The new species is morphologically almost identical to N. sivasothii , except for the larger forked extension on fore tarsomere 4 in male and the very different male genitalia. The outer branch of the apical fork on fore tarsomere 4 is slightly longer than the inner branch, the outer branch is slightly shorter than the inner branch in N. sivasothii .

The wing is brownish tinged and only the Tp is dark seamed. In N. sivasothii the wing is darker and the longitudinal veins as well as Tp are generally black seamed. Vein M1+2 includes a short stub on the apical bend in the new species. Such a stub was never observed in the large populations of N. sivasothii in Singapore.

Presently females of the new species are indistinguishable from females of N. sivasothii . Both species have been collected together. For this reason, no females were included in the material examined section.

Figures

FIGURE 1. Ngirhaphium chutamasae sp. nov., male habitus; inset: apical tarsomeres on fore leg, showing the large fork-like extensions on tarsomere 4 and the additional claw-like structure on tarsomere 5 (photo: J. Brecko). Scale = 1 mm.

FIGURES 2 – 6. Ngirhaphium chutamasae sp. nov., holotype male genitalia: 2. Left ventral surstylus; 3. Lateral view of genital capsule with left ventral surstylus removed; 4. Cerci dorsally; 5. Dorsal surstylus in ventral view; 6. Ventral view of genital capsule. Abbreviations: ae: aedeagus; c: cercus; ds: dorsal surstylus; f: foramen; hy: hypandrium; sp: sperm pump; vs: ventral surstylus. Scale = 0.1 mm.