New species and records of the genus Hercostomus Loew (Diptera: Dolichopodidae) from Thailand mangroves, with notes on the Hercostomus fauna of Singapore mangroves Author Samoh, Abdulloh Princess Maha Chakri Sirindhorn Natural History Museum (PSUNHM), Prince of Songkla University, Kho Hong, Hat Yai, Songkhla, Thailand, 90110 Author Grootaert, Patrick National Biodiversity Centre, NParks, Singapore; Lee Kong Chian Natural History Museum, National University of Singapore; Department of Entomology, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, B- 1000 Brussels, Belgium & Princess Maha Chakri Sirindhorn Natural History Museum (PSUNHM), Prince of Songkla University, Kho Hong, Hat Yai, Songkhla, Thailand, 90110 text Zootaxa 2024 2024-04-30 5446 2 179 204 http://dx.doi.org/10.11646/zootaxa.5446.2.2 journal article 10.11646/zootaxa.5446.2.2 1175-5326 11101578 B1B73538-4AD4-4E0B-843F-74411F6E9AB3 Hercostomus plumatus Zhang, Yang & Grootaert, 2008 (New record) ( Figs 15 , 16 ) Material examined. THAILAND : Nakhon Si Thammarat Province , 10 ♂ , Pak Pha Nang Bang Kong Khong ( 8°24’09.4”N 100°11’29.9”E ), 29.IV.2015 , coll. A. Samoh. Songkhla Province , 3 ♂ , Chana District , Ban Nathab ( 7°01’25.8”N 100°43’05.0”E ), sweep netting, 27.IX.2014 , coll. A. Samoh. Surat Thani Province , 1 ♂ , 1 ♀ , Phum Riang district , Ban Nua Nam ( 9°23’34.0”N 99°15’24.0”E ), 22.IV.2015 , coll. A. Samoh. SINGAPORE : 1605 specimens have been collected in mangroves all over Singapore while nearly 500 specimens have been barcoded. Remarks. Body length 2.4–2.7 mm , wing length 2.2–2.5 mm . First flagellomere 1.2 times as long as wide ( Zhang et al. , 2008 ). Fore coxa yellow, mid and hind coxae brownish. Dorsal lobe of surstyli with plumose hair. Distribution. THAILAND : Nakhon Si Thammarat , Songkhla , and Surat Thani ( Fig. 7 ).