Ngirhaphium meieri Samoh & Grootaert, 2019

Samoh, Abdulloh, Satasook, Chutamas & Grootaert, Patrick, 2019, NGS-barcodes, haplotype networks combined to external morphology help to identify new species in the mangrove genus Ngirhaphium Evenhuis & Grootaert, 2002 (Diptera: Dolichopodidae: Rhaphiinae) in Southeast Asia, Raffles Bulletin of Zoology 67, pp. 640-659 : 646-651

Ngirhaphium meieri Samoh & Grootaert , new species

( Figs. 7–9 , 10D )

Diagnosis. A large species with apical segment of arista twice as long as basal aristal segment. Prongs on fore tarsomere 4 with exterior (posterior) prong sharply pointed longer than interior (anterior) prong. Apical tarsomere of fore leg with a black somewhat twisted prong below the posterior claw. Apical tarsomere of mid leg with a double dorsal comb of black squamiform bristles forming a flag. Mesonotum and abdominal tergites shining metallic green.

Cercus in lateral view slightly shorter than dorsal surstylus. Cercus brown, tip pointed bearing a single long, yellow bristle. Dorsal surstylus mushroom-shaped, yellowish brown, bordered with short, yellow bristles.

Material examined. HOLOTYPE ♂, labelled: THAILAND: Phang Nga province, Takuapa, Bang Yai , (8°54′27.5″N, 98°23′59.6″E), Samoh A, sweep netting, 9 February 2015

( PSUNHM). (Doli3 _26_005E, collected Abdulloh Samoh, PSUNHM).

Paratypes. 2 males; 2 females, Phang Nga province, Takuapa, Bang Yai , (8°54′27.5″N, 98°23′59.6″E), Samoh A, sweep netting, 9 February 2015 ( PSUNHM) ; 3 females, Phang Nga province, Takuapa, Bang Yai , (8°54′27.5″N, 98°23′59.6″E), Samoh A, sweep netting, 13 July 2018 ( PSUNHM) ; 1 male, Ranong province, Kraburi, Lam Liang, Phra Khayang cave (10°19′25.5″N 98°45′58.0″E), Samoh A., sweep netting, 10 July 2018 ( PSUNHM) .

Etymology. The species is dedicated to Rudolf Meier, head of Evolutionary Biology Laboratory, Department of Biological Sciences at the National University of Singapore (NUS), who provided us an opportunity to learn and do a molecular study of the marine dolichopodid flies.

Description. Male. ( Fig. 6 ). Length body: 8.6-8.8 mm; wing: 8.4-8.6 mm. Head. Frons shining metallic green (not dusted), deeply excavated. Face greenish brown in ground-colour, silvery grey dusted; apex of face and clypeus yellowish brown in ground-colour, parallel-sided. Eyes pass beyond border of face; eyes densely set with minute white hairs. Ocellar callus globular protruding from frons with two 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 apical bristle. Labella brown with black hairs. Antenna long, completely black. First segment long, 3 times as long as second segment; second segment short, apically with crown of short black bristles. Third segment very long strap-shaped, laterally flattened, with a lateral rim, about 6.5 times as long as width at base. Arista apical, apical segment twice as long as basal article, gradually tapering towards tip. Total length antenna: 2.1 mm. Length of scape: 0.39; pedicel: 0.13; postpedicel: 0.87; basal aristal article: 0.23; apical aristal article: 0.468 (all 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, fine upper and 2 lower propleural bristles (lower one twice as long as upper).

Legs ( Fig. 5 ) yellow, all bristles black. All coxae brownish black in ground-colour, covered with fine greyish dusting. All trochanters brown. Tip of hind tibia annulated brown at tip. Fore tarsus with tip of tarsomere 1 brownish, tarsomeres 2–4 almost entirely brown (especially dorsally), tarsomere 5 entirely black. Mid tarsus more yellowish than fore tarsus, with apical tarsomere black; hind tarsus black but base of tarsomere 1 and 2 paler.

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, extending over tarsomere 5; exterior (posterior) prong longer than interior (anterior) prong, both sharply pointed when seen in lateral view. Apical tarsomere with a black, blunt, somewhat twisted prong below the posterior claw, as long as apical tarsomere.

Two well-developed pulvilli and empodium present. Length of femur, tibia and tarsal segments (in mm): 1.6: 1.62: 0.8: 0.26: 0.2: 0.16: 0.2.

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 of mid leg with a double, dorsal comb of black squamiform bristles forming a flag ( Fig. 5 inset). Length of femur, tibia and tarsal segments (in mm): 1.9: 2.4: 1.3: 0.74: 0.54: 0.3: 0.3.

Hind leg. Coxa bare. Trochanter with a long dorsal bristle. Hind femur thicker than fore and mid 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): 1.8: 3.3: 1.4: 0.8: 0.64: 0.36: 0.4.

Wing ( Fig. 6 ) tinged brownish (paler on imaged specimen), anteriorly between costa and R 4+5 a little darker yellowish brown. Tp (crossvein r-m) brown seamed. Veins dark brown, yellowish at base. M 1+2 sharply bent upwards and ending in costa closely near tip of R 4+5. Tp straight, a little longer than apical part of M 3+4. Anal vein reaching wing border. Haltere with white knob, stem a little infuscate. Squama white, with long white cilia.

Abdomen subshining dark metallic green. Tergites densely set with quite long black bristles; hind-marginal bristles slightly longer than other bristles. Only tergites 1 and 5 with much longer marginal bristles. Sternites with very short hairs except for longer marginals on sternite 4.

Terminalia ( Fig. 8 ). Cercus yellowish brown to brown, slightly shorter than dorsal surstylus ( Fig. 8A ). Both cerci look like fused for almost entire length, only tips free ( Fig. 8B ). Tip of cercus pointed, with a single yellow apical bristle, dorsally set with long blackish brown bristles, sometimes pale at tip. Dorsal surstylus brown, paler than cercus, with much widened tip in the shape of a mushroom, forming a transverse clasper on cercus, bordered with short but stout yellow bristles ( Fig. 8A ). Ventral and dorsal surstyli not fused. Ventral surstylus yellowish, oval ( Fig. 8C ), tip with 3 long bristles on apical border and a few short hair-like bristles at inside. Hypandrium dorsally split, with a large rounded black protuberance set with denticles ( Fig. 8A ).

Female. ( Fig. 7 ). Body: 8.9–9.0 mm; Wing: 8.6–8.8 mm.

The female has larger labellae than the male, which is a characteristic of the genus.

The antenna is slightly shorter than in male with apical aristal segment twice as long as basal segment. Length of scape: 0.377; pedicel: 0.13; postpedicel: 0.741; basal aristal article: 0.234; apical aristal article: 0.455 (all in mm). Total length 1.94 mm.

Fore tarsomere 4 without dorsal fork. Tarsomere 5 with an apical dorsal projection and without ventral prong below the exterior claw. Mid tarsomere 5 without dorsal squamiform bristles.

Distribution. Phang Nga and Ranong provinces, Thailand, Andaman Sea (Indian Ocean).

Remarks. The new species is morphologically similar to N. sivasothii and even more to N. chutamasae . Differences can be found in the key to the Southeast Asian species here below.

RAFFLES BULLETIN OF ZOOLOGY 2019

Figures

Fig. 7. Ngirhaphium meieri, new species, female habitus. Scale = 1 mm.

Fig. 8. Ngirhaphium meieri, new species, holotype male terminalia: A, Lateral view of genital capsule with left ventral surstylus removed; B, Cerci dorsally; C. Left ventral surstylus; D, Ventral view of genital capsule. Abbreviations: ae = aedeagus; c = cercus; ds = dorsal surstylus; hy = hypandrium; sp = sperm pump; vs = ventral surstylus. Scale = 0.1 mm.

Fig. 9. Distribution map of Ngirhaphium meieri, new species and Ngirhaphium thaicum, new species.

Fig. 10. Haplotype network of Ngirhaphium murphyi. Singapore: Pulau Ubin, Mandai Sungei Buloh; Thailand: Satun and Krabi.

Fig. 6. Ngirhaphium meieri, new species, male habitus (photo: Abdulloh Samoh). Scale = 1 mm.

Fig. 5. Ngirhaphium thaicum, new species male terminalia (27_009) A, epandrium left side; B, cerci dorsal view; C, left surstylus inside view. Scale = 0.1 mm.