Ngirhaphium thaicum 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 : 644-645

Ngirhaphium thaicum Samoh & Grootaert , new species

( Figs. 2E, F , 3–5 )

Material examined. Holotype male: THAILAND: Ban Nua Nam, Phum Riang, Chaiya , Surat Thani (9°23′34.0″N, 99°15′24.0″E), Samoh, A., sweep netting, 22 April 2015 ( PSUNHM). (barcode: Thai_27-018_Abdullah_ ABDO08 _ SuratThani)

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Paratypes: THAILAND: 1 male, Ban Elet, Tha Yang, Mueang , Chumphon province (10°22′24.0″N 99°13′35.4″E), Samoh, A., sweep netting, 16 February 2015. (barcode: Thai _27-004_ Abdullah _ ABDO07 _ Chumphon) . 1 male, Ban Nua Nam, Phum Riang, Chaiya , Surat Thani (9°23′34.0″N, 99°15′24.0″E), Samoh, A., sweep netting, 18 April 2015. (barcode: Thai _27-009_ Abdullah _ ABDO07 _ SuratThani) . 1 female, Ban Elet, Tha Yang, Mueang , Chumphon province (10°22′24.0″N 99°13′35.4″E), Samoh, A., sweep netting, 16 February 2015. (barcode: Thai _27-006_ Abdullah _ ABDO07 _ Chumphon) . 4 males; 10 females, Ban Elet, Tha Yang, Mueang , Chumphon province (10°22′24.0″N 99°13′35.4″E), Samoh, A., sweep netting, 16 February 2015 . 1 male; 1 female, Ban Elet, Tha Yang, Mueang , Chumphon province (10°22′24.0″N 99°13′35.4″E), Samoh, A., Malaise trap, 18 February 2015 . 1 female, Khao Than, Tha Chang , Surat Thani province (9°19′43.4″N, 99°12′31.6″E) Samoh, A., Malaise trap, 21 April 2015 . 1 male; 1 female, Ban Nua Nam, Phum Riang, Chaiya , Surat Thani (9°23′34.0″N, 99°15′24.0″E), Samoh, A., Malaise trap, 22 April 2015 . 8 males; 12 females, Ban Nua Nam, Phum Riang, Chaiya , Surat Thani (9°23′34.0″N, 99°15′24.0″E), Samoh, A., sweep netting, 18 April 2015 . 3 males, 6 females, Khlong Wan, Muang, Prachuap Kirikhan (11°45′26.2″N 99°47′36.3″E), 8 July 2018 Samoh, A. 2 males; 1 female, Ban Salak Khok, Koh Chang , Trat (12°01′30.1″N 102°23′35.9″E), Samoh, A., sweep netting, 3 November 2018 . 2 female, Pak Nam, Sawee , Chumphon province (10°16′41.5″N 99°09′43.9″E), Samoh, A., sweep netting, 7 July 2018 ( PSUNHM) . CAMBODIA: 1 male, 2 females, Koh Kong province, Peam Krasaop WS, Boeng Kayak 11°30′31″N 103°05′50″E 9–10 October 2015 (Malaise trap, collected J. Constant & J Bresseel; RBINS) . Male with barcode reference JP3C_ Ngi-cambo _ Misc 002 .

Mid leg. Tarsomere 5 with some longer anterior and posterior bristles though not forming a flag. Ratio of femur, tibia and tarsomeres in mm: 1.96: 2.6: 1.36: 0.64: 0.54: 0.28: 0.28. Extended diagnosis. Male ( Fig. 3 ) Body: 7.2–7.7 mm; wing: 5.6–5.9 mm. A large species of the caeruleum complex with mesonotum and tergites shining metallic green. Antenna: scape: 0.39; pedicel: 0.12; postpedicel: 0.82; basal aristal segment: 0.2; apical aristal segment: 0.325 (all in mm). Apical aristal segment thin (filiform), about 1.5 times as long as basal aristal segment.

Thorax with a green metallic shine.

Wing ( Fig. 3 ) clear, but anterior two cells brownish tinged. Veins black and weakly seamed brown.

Legs ( Fig 3 ). Fore leg. Tarsomere 4 with an apical fork, the inner prong (anterior) much longer than the outer (posterior) prong. Tarsomere 5 with an apical protuberance. Ratio of femur, tibia and tarsomeres in mm: 1.4: 1.2: 0.9: 0.2: 0.3: 0.16: 0.2.

Hind leg: Ratio of femur, tibia and tarsomeres in mm: 1.92: 3.2: 1.4: 0.68: 0.54: 0.32: 0.26.

Abdomen with a green metallic shine.

Male terminalia ( Fig. 5 ) with dorsal and ventral surstylus at right side fused ( Fig. 2E , 5C ); dorsal and ventral surstyli separated at left side. Tip of both right and left dorsal surstyli pointed; tip on inside with short yellow bristles. Right and left ventral surstylus with dorsal border and sometimes the inside bearing a few protuberances. Cerci a little shorter than surstyli so that they are concealed between the surstyli.

Female ( Fig. 4 ) Body: 7.7–8 mm; wing: 6.7–6.9 mm. Similar to male but lacking the apical fork on the fore tarsomere 4 as well as the prong under the anterior claw.

Distribution. Trat, Prachuap Kirikan, Chumphon, Surat Thani Province, and Cambodia. Gulf of Thailand (South China Sea).

Remarks. This is one of the largest Ngirhaphium species. They prefer open areas without canopy cover and with soft mudflat.

Figures

Fig. 2. Ngirhaphium caeruleum-complex. View of inside of the dorsal surstylus of the left side and the fused dorsal and ventral surstyli of the right side. Scale = 0.1mm. A, green caeruleum from Tutong, Brunei (ZRCBDP0066395) at 1.6 % from the Semakau population; B, green caeruleum from Pulau Tekong, Singapore (ZRCBDP0001462) at 0.6% from the Semakau population; C, green caeruleum from Pulau Ubin, Singapore (ZRC_BDP_0084430) at 0.6% from the Semakau population; D, blue caeruleum from the type locality on Semakau Island, Singapore (ZRCBDP0118762); E, green thaicum, new species from Surat Thani, Thailand (24-018) at 4.2% from the Semakau population; F, green thaicum, new species from Cambodia (JP3C_Ngi-cambodiensis_Misc002) within the variability of the southern Thailand populations.

Fig. 3. Ngirhaphium thaicum, new species male habitus. Scale = 1 mm.

Fig. 4. Ngirhaphium thaicum, new species habitus female. 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.