Epeorus (Belovius) khayengensis Boonsoong & Braasch, 2010

Boonsoong, Boonsatien & Braasch, Dietrich, 2013, Heptageniidae (Insecta, Ephemeroptera) of Thailand, ZooKeys 272, pp. 61-93 : 64-65

Epeorus (Belovius) khayengensis Boonsoong & Braasch, 2010 Figs 1B, 1G5 A–B 9D

Epeorus (Belovius) khayengensis Boonsoong & Braasch, 2010: 13-17, Figs 53-68. (orig.)

Larva.

Braasch and Boonsoong 2010: 13-17, Figs 53-68.

Adult.

Unknown.

Eggs.

Egg chorion of Epeorus khayengensis very smooth without any peculiar structure (Fig. 5A), 2-3 micropyles visible in the equatorial area (Fig. 5B).

Distribution.

Huai Khayeng stream (Thong Pha Phum district, Kanchanaburi province).

Diagnosis.

The larva of Epeorus khayengensis (Fig. 9D) can be distinguished from that of othercongeners by abdominal terga 2-9 without long acute median spine on posterior margin, but bearing long hair-like setae.

Habitat and biology.

The larva of Epeorus khayengensis inhabits tropical headwater streams approximately 210 m in alt. The streams range between 6-7 m in width and 10-11 cm in depth. The water temperature ranges between 22-25°C, pH between 6.35-7.15, total dissolved solids are between 27-34 mg/L, and conductivity is between 41-53 µS /cm. The larvae are found in eroded areas of streams where moderately flowing over cobble and sandy bottom.

Remarks.

Braasch and Boonsoong (2010) described this species from Thailand based on nymphal specimens, and deposited them in the Zoological Museum, Kasetsart University (ZMKU), Bangkok. The adults of Epeorus khayengensis are unknown.