Labiobaetis cf. paraoperosus Kaltenbach & Gattolliat, 2018 Material examined. Thailand • 3 larvae; Ranong Prov., Mueang Distr., Punyaban Waterfall; 10°03'54"N, 98°40'13"E; 52 m; 19.vi.2018; leg. C. Suttinun; on slides; GBIFCH 01223074, GBIFCH 00596156; VMCMU; GBIFCH 00592514; MZL • 9 larvae; Ranong Prov., Mueang Distr., Huai Por Ta Hin Rao; 09°52'08"N, 98°37'32"E; 20 m; 20.vi.2018; leg. C. Suttinun; in alcohol; GBIFCH 00763804; VMCMU; GBIFCH 00763803; MZL. Diagnosis. Larva. Following combination of characters differentiate L. paraoperosus from other species of the group operosus: maxillary palp much longer than galea-lacinia, segment II with slight distolateral excavation; labial palp segment II with broad thumb-like, apically rounded distolateral protuberance; labial palp segment III oblong. Remark. The larva has no morphological difference to L. paraoperosus from Indonesia (Sumatra), but there is a genetic distance of 12 % (COI, K 2 P). Distribution. Thailand (Fig. 32 c), but L. paraoperosus is known from Sumatra (Indonesia).

Published as part of Kaltenbach, Thomas, Gattolliat, Jean-Luc, Boonsoong, Boonsatien & Suttinun, Chanaporn, 2025, New species of Labiobaetis Novikova & Kluge from Thailand (Ephemeroptera, Baetidae), pp. 213-276 in ZooKeys 1258 on pages 213-276, DOI: 10.3897/zookeys.1258.166681