Potamanthus (Potamanthodes) formosus Eaton, 1892

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

Potamanthus (Potamanthodes) formosus Eaton, 1892

Figures 10A , 11A , 14 , 15

Materials examined.

1 larva, Thailand, Chanthaburi province, Makham district, Ban Pa Rim Tarn homestay, 1 2°51'00.0"N, 102°12'17.1"E, 5.X.2019, B. Boonsoong leg. (ZMKU) ; 2 larvae, Kanchanaburi province, Huai Pak Kok , 14°39'34.4"N, 98°32'02.3"E, 175 m, 11.VII.2019, S. Kwanboon leg. (ZMKU) ; 2 larvae, Chiang Rai province, Huai Kang Pla waterfall, 20°05'21.6"N, 99°46'47.8"E, 519 m, 5.III.2021, S. Kwanboon leg. (ZMKU) ; 4 larvae, Chiang Rai province, Klong Mae Salong , 20°09'52.0"N, 99°40'06.8"E, 6.III.2021, S. Kwanboon leg. (ZMKU) ; 1 larva, Nan province, Ban Ratsadonsamakkhi , 18°52'23.4"N, 100°49'54.1"E, 59 m, 28.XI.2020, B. Boonsoong leg.

Diagnosis.

The larvae of Potamanthus formosus Eaton, 1892 can be distinguished from those of other Potamanthus (Potamanthodes) species based on the following characteristics: i) dorsal forefemora with simple stout setae (Fig. 11A ), ii) a subapical cluster of setae on the foretibia, iii) short mandibular tusk (0.10-0.23 × length of the head) (Fig. 10A ), and iv) relatively small body length.

Distribution.

Chanthaburi, Kanchanaburi, Nan, and Chiang Rai provinces.

Remark.

The adult of P. formosus was described by Eaton (1892) based on materials from Myanmar. Imanishi (1940) described the species Potamanthus kamonis based on imaginal and larval materials from Japan, and P. kamonis was synonymized with P. formosus by Ueno (1969). Potamanthus formosus is widely distributed in East Asia and Southeast Asia (China, Japan, South Korea, Malaysia, Vietnam, Myanmar, and Thailand). In the present study, the specimens were found in eastern, western, and northern Thailand, so P. formosus is the most widespread potamanthid in Thailand (Fig. 14 ).

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.