Rhoenanthus (Potamanthindus) obscurus Navas , 1922

Kwanboon, Sedtawut, Sartori, Michel & Boonsoong, Boonsatien, 2021, Behningiidae and Potamanthidae (Insecta, Ephemeroptera) in Thailand, ZooKeys 1067, pp. 57-82 : 57

Rhoenanthus (Potamanthindus) obscurus Navas, 1922

Figures 10C, D , 11C , 14 , 15

Materials examined.

1 female imago (reared) and 1 male imago (reared), Thailand, Chiang Mai province, Mae Ping river, Elely Cafe , 19°04'08.4"N, 98°56'28.8"E, 15.XI.2020, S. Kwanboon leg. (ZMKU) .

Diagnosis.

The larvae of Rhoenanthus obscurus can be distinguished from those of other Rhoenanthus (Potamanthindus) species based on the following characteristics: i) medium-sized body (12-17 mm), ii) mandibular tusks arched inward about 28° (angle measurement as shown in Fig. 10D ), iii) length of mandibular tusks ca 0.7-0.8 × length of the head, and iv) length of foretibiae ca 1.32-1.49 × length of the forefemora and about 2.55-3.02 × length of the foretarsi (Fig. 11C ) ( Bae and McCafferty 1991; Nguyen and Bae 2006).

Distribution.

Chiang Mai province.

Remark.

The larva of R. obscurus was originally described by Gose (1969) as Potamanthus sp. TPA and collected from Thailand (Chantaburi province). Bae and McCafferty (1991) redescribed the larva with material from Mae Ping river, Chiang Mai province. In this study, we found this species in the same river as in the previous study. Our specimens were reared in the laboratory and successfully raised to the imago stage.

Figures

Figure 10. Larval morphology (head and mandibular tusk) A Potamanthus formosus Eaton, 1892 B Rhoenanthus magnificus Ulmer, 1920 C R. obscurus Navas, 1922 D angle measurement of mandibular tusk E R. distafurcus Bae & McCafferty, 1991 F R. speciosus Eaton, 1881.

Figure 11. Larval morphology (foreleg) A Potamanthus formosus Eaton, 1892 B Rhoenanthus magnificus Ulmer, 1920 C R. obscurus Navas, 1922 D R. distafurcus Bae & McCafferty, 1991 E R. speciosus Eaton, 1881. Scale bar: 1 mm.

Figure 14. Distribution map of the family Potamanthidae in Thailand.

Figure 15. The COI phylogenetic construction based on the maximum likelihood (ML) analysis of family Potamanthidae in Thailand.