Cloeon viridulum Navás, 1931

Noenrimnong, Chayanon, Suttinun, Chanaporn, Tungpairojwong, Nisarat & Boonsoong, Boonsatien, 2026, Taxonomic insights into the diversity of Cloeon Leach, 1815 (Ephemeroptera, Baetidae) in Thailand, ZooKeys 1266, pp. 1-39 : 1-39

publication ID	https://doi.org/10.3897/zookeys.1266.176616
publication LSID	lsid:zoobank.org:pub:8478A1BF-2692-4B88-986C-3751CCC8E056
DOI	https://doi.org/10.5281/zenodo.18158322
persistent identifier	https://treatment.plazi.org/id/EF08435E-D5E0-5263-9B18-021773E0758D
treatment provided by	ZooKeys by Pensoft
scientific name	Cloeon viridulum Navás, 1931
status

Treatment

Cloeon viridulum Navás, 1931 View in CoL

Figs 5 A – C View Figure 5 , 7 D View Figure 7 , 12 A – D View Figure 12 , 17 A – D View Figure 17 , 26 A – D View Figure 26 , 27 E View Figure 27 , 28 D View Figure 28 , 29 B View Figure 29

Cloeon viridulum Navás, 1931: 7, fig. 14 (original description, female subimago). View in CoL

Cloeon viridulum View in CoL : Navás 1933: 17. Wu 1935: 251. Ulmer 1936: 215. Gui 1985: 82. Alba-Tercedor and Peters 1985: 221. Sun et al. 2015: 58 (habitat). Si et al. 2017: 1 (transcriptome). Ying et al. 2021: 12 ( C. virens View in CoL described by Ulmer (1925, 1936) was synonymised with C. viridulum View in CoL ).

Material examined.

• 2 female imagos, Nakhon Ratchasima Prov., Motorway M 6 , 14°53'09.8"N, 101°37'17.5"E, 19. V. 2025, B. Boonsoong leg. ( ZMKU) GoogleMaps ; • 1 nymph, 3 male imagos, 2 female imagos, Kanchanaburi Prov., The River Kwai Bridge Resort , 14°02'26.7"N 99°30'26.6"E, 05. VII. 2025, B. Boonsoong leg. ( ZMKU) GoogleMaps .

Description

(in alcohol). Female subimago. See Navás (1931) (original description).

The female imagos are characterised by a green to yellowish-green head, with a pale-yellow midline flanked by two dark brown longitudinal stripes across the central region (Fig. 26 A View Figure 26 ). The thorax is yellowish-green, with a yellowish-green midline bordered by two narrow, long, pale brown longitudinal stripes extending from the head (Fig. 26 A View Figure 26 ). The abdominal terga are yellowish-green, with uniformly brown to dark reddish-brown pigmentation. Terga II – VIII have a pale midline flanked by a pair of pale spots or drop-shaped markings, while the lateral margins of each anterior segment bear dark reddish-brown spots or short stripes (Fig. 17 A View Figure 17 ). The abdominal sterna exhibit dark reddish-brown spots along the lateral margins of segments II – VIII (Fig. 17 C View Figure 17 ). The wings are hyaline, with yellowish-green to translucent yellow venation in the costal and subcostal areas (Fig. 12 C View Figure 12 ).

The mature nymphs possess a head with two rows of irregular brown spots (Fig. 5 A View Figure 5 ). The abdominal terga are dark green to brown, with uniformly dark brown to brown colouration. Terga II – IX bear a pale midline flanked by a pair of pale spots or drop-shaped marks. The abdominal sternum X lacks dark pigmentation (Fig. 5 C View Figure 5 ).

Male subimago (in alcohol). Body length 3.05–3.11 mm.

Head: Dark brown. Eyes orange to rust-coloured with olive green lower eyes (Fig. 12 B View Figure 12 ).

Thorax: Olive green to dark brown, with white to cream-white midline (Fig. 12 B View Figure 12 ).

Legs: White colouration (Fig. 12 B View Figure 12 ).

Abdominal terga: White; posterior parts of segments II – VI bear a pale pair of rust-coloured stripes. Lateral margins of segments II – VII anteriorly with dark reddish-purple spots or stripes. Segments VII – X rust-coloured (Fig. 17 B View Figure 17 ).

Abdominal sterna: White; lateral margins of segments II – VII anteriorly have dark reddish-purple spots or stripes. Segments VII – X white (Fig. 17 D View Figure 17 ).

Wings: Milky white, with cream-white veins and no dark bands. Posterior margin with sparse microtrichia (Fig. 12 D View Figure 12 ).

Egg. Width 49.78 μm; height 84.99 μm. Oval-shaped; surface covered with pits, with irregularly distributed depressions of varying sizes and irregular dimensions and unevenly distributed across the surface (Fig. 26 C, D View Figure 26 ).

Distribution.

Northeastern Thailand ( Nakhon Ratchasima province); western Thailand ( Kanchanaburi province).

Remarks.

The female subimago of Cloeon viridulum was described by Navás (1931) based on materials from China. Ours is the first record of this species in Thailand. In this study, we provide the first description of the male subimago and egg structure of C. viridulum .