Prosopistoma annamense Soldan & Braasch, 1984

Boonsoong, Boonsatien & Sartori, Michel, 2019, Review and integrative taxonomy of the genus Prosopistoma Latreille, 1833 (Ephemeroptera, Prosopistomatidae) in Thailand, with description of a new species, ZooKeys 825, pp. 123-144 : 125

Prosopistoma annamense Soldan & Braasch, 1984 Figures 1A, 1B, 2A, 2B, 2C, 2D, 3A, 3B, 3C, 12A, 12B, 12C, 14

Prosopistoma annamense Soldán & Braasch, 1984: 370-376, figs. 2, 4, 6, 8, 13, 14. (orig.); Barber-James, 2009: 153-154, Table 2 (morph. matrix); Tungpairojwong & Boonsoong, 2011: 67-68; Shi & Tong, 2013: 95 (key).

Material examined.

THAILAND; 1 larva, Chanthaburi province, Klong Kla Seu Yai, Khao Kitchakut, 12°52'35.94"N, 102°05'48.3"E, 40 m, 7.II.2013, 2 larvae, same place, 6.VII.2018, B Boonsoong leg. (ZMKU); 1 larva, Nakhon Nayok province, Wang Ta Krai, 14°19'35.9"N, 101°18'05.9"E, 65 m, 24.III.2013, B Boonsoong leg. (ZMKU); 5 larvae, Kanchanaburi province, Thong Pha Phum, Phu Iyara Resort, 14°37'34.4"N, 98°34'17.0"E, 207 m, 6.IV.2013, B Boonsoong leg. (ZMKU), 1 larva same data (MZL, GBIFCH00657966); 1 larva, Ban Pra Chum Mai, 14°35'01.4"N, 98°34'54.3"E, 233 m, 26.IV.2014, B Boonsoong leg. (ZMKU); 5 larvae, Kanchanaburi province, Pung Wan Resort, 14°12'20"N, 98°03'36"E, 28 m, 14.X.2015, B Boonsoong leg. (ZMKU), 1 larva same data (MZL, GBIFCH00657965); 3 larvae, Loei province, Ban Non Pattana, 17°06'24"N, 101°28'44"E, 530 m, 1.II.2016, B Boonsoong leg. (ZMKU); 3 larvae, Ratchaburi province, Kang Som Maew, Suan Phueng, 13°24'27.6"N, 99°16'51.3"E, 206 m, 13.II.2016, B Boonsoong leg. (ZMKU); 6 larvae, Loei province, Ban Non Pattana, 17°06'24"N, 101°28'44"E, 530 m, 19.III.2016, B Boonsoong leg. (ZMKU); 2 larvae, Nakhon Nayok province, Wang Ta Krai, 14°20'9.42"N, 101°18'22.5"E, 67 m, 25.II.2017, B Boonsoong leg. (ZMKU); 2 larvae, Chanthaburi province, Klong Sa Tor Bon, 12°43'12.42"N, 102°23'19.26"E, 115 m, 5.VII.2018, B Boonsoong leg. (ZMKU).

Diagnosis.

The larvae of P. annamense can be distinguished from those of other Oriental congeners by (i) apex of the inner margin of the fore tibiae, with 4-6 serrated pectinate spines (Fig. 3B), (ii) three long, finely serrated bristles at the base of the inner incisor, on both right and left mandible, (iii) segment III of the maxillary palp slightly shorter than 1/3 the length of segment II and (iv) posterolateral spines at segments VII and VII parallel to or bent outwards from the body axis (Fig. 1A, B).

Distribution.

Loei province (NE), Nakhon Nayok province (C), Chanthaburi province (E), Kanchanaburi province (W), Ratchaburi province (W).

Remarks.

The larvae of P. annamense were originally described by Soldán and Braasch (1984) and collected from Vietnam (Thuan Hai province). They are widely distributed in southern and central Vietnam. Tungpairojwong and Boonsoong (2011) reported this species in middle and moderately disturbed streams in Loei province (NE), Chaiyaphum province (NE) and Kanchanaburi province (W). In this study, we found this species in several provinces, and it seems to have a wide distribution in Thailand. Surprisingly, we found larvae on the banks of the Khwae Noi River (Kanchanaburi province) (Fig. 12C). This is the first report of Prosopistoma larvae in large rivers in Thailand, and the larvae collected from large rivers are paler than those larvae from streams (Fig. 1B).