Thalerosphyrus vietnamensis Dang, 1967

Sutthacharoenthad, Waranid, Sartori, Michel & Boonsoong, Boonsatien, 2019, Integrative taxonomy of Thalerosphyrus Eatonı 1881 (Ephemeropteraı Heptageniidae) in Thailand, Journal of Natural History 53 (23), pp. 1491-1514 : 1498-1500

Thalerosphyrus vietnamensis Dang, 1967

( Figures 3 (a–c), 6(c), 7(c), 9(c), 10(c), 11(c))

Materials examined

THAILAND; 1 larva (in ethanol), Padsaduklang, Kanchanaburi Prov., 14.553611°N, 98.571389°E, alt. 317 m, 20-II-2016, B. Boonsoong leg. ( ZMKU); 2 larvae (in ethanol), Karome waterfall, Nakhon Si Thammarat Prov., 8.369071°N, 99.735035°E, alt. 104 m, 13-IV -2016, B. Boonsoong leg. ( ZMKU); 2 larvae (in ethanol), Ton Sator waterfall, Phatthalung Prov., 7.195383°N, 100.071533°E, alt. 101 m, 12-III-2016, B. Boonsoong leg. ( ZMKU); 1 larva (on slide), Nam Thob Ranger , Loei Prov., 17.259722°N, 101.413611°E, alt. 338 m, 1-I-2016, B. Boonsoong leg. ( ZMKU); 3 larvae (1 on slides; 2 in ethanol), Wang Ta Krai , Nakhon Nayok Prov., 14.326639°N, 101.301639°E, alt. 20 m, 23-I-2016, B. Boonsoong leg. ( ZMKU); 1 larva (in ethanol), Baan Bor Wee waterfall, Ratchaburi Prov., 13.476317°N, 99.241850°E, alt. 195 m, 15-VII-2015, B. Boonsoong leg. ( ZMKU); 3 larvae (1 on slide; 2 in ethanol), Khao Luang waterfall, Lan Sa Ka, Nakhon Si Thammarat Prov., 8.369071°N, 99.735035°E, alt. 533 m, 2-VII-2016, B. Boonsoong leg. ( ZMKU); 2 larvae (1 on slide; 1 in ethanol), Mae Na , Chiang Dao, Chiang Mai Prov., 19.320300°N, 98.890550°E, alt. 742 m, 11-III-2017, B. Boonsoong leg. ( ZMKU); 3 larvae (2 on slides; 1 in ethanol), Baan Prachummi , Kanchanaburi Prov., 14.583722°N, 98.581750°E, alt. 252 m, 27-V-2017, W. Sutthacharoenthad leg. ( ZMKU); 5 larvae (in ethanol), Huai Pueng , Kanchanaburi Prov., 14.972782°N, 98.897135°E,alt. 710 m., 4-VI-2017, B. Boonsoong leg. ( ZMKU); 5 larvae (in ethanol), Khli Ti Creek , Kanchanaburi Prov., 14.954914°N, 98.923592°E, alt. 690 m., 2-VI-2017, B. Boonsoong leg. ( ZMKU); 6 larvae (in ethanol), Wat Lan Sang , Tak Prov., 16.781433°N, 99.021183°E, alt. 420 m., 25-XII-2017, W. Sutthacharoenthad leg. ( ZMKU); 6 larvae (in ethanol), Tha Ley , Tak Prov., 16.741133°N, 99.045167°E, alt. 327 m., 26-XII-2017, W. Sutthacharoenthad leg. ( ZMKU); 5 larvae (in ethanol), Um Yom , Tak Prov., 16.804350°N, 99.002300°E, alt. 249 m., 26-XII-2017, W. Sutthacharoenthad leg. ( ZMKU); 3 larvae (in ethanol), Mae Ya-U, Tak Prov., 16.741517°N, 98.809083°E, alt. 320 m., 26-XII -2017, W. Sutthacharoenthad leg. ( ZMKU); 2 larvae (in ethanol), Mae Ka Sa Mai , Tak Prov., 16.875517°N, 98.621683°E, alt. 200 m., 26-XII-2017, W. Sutthacharoenthad leg. ( ZMKU); 1 larva (in ethanol), Huai Sat Lek , Hua Hin district, Prachuap Khiri Khan Prov., 12.635750°N, 99.509917°E, alt. 166 m., 25-II-2018, B. Booonsoong leg. ( ZMKU); 6 larvae (in ethanol), Ai Ka Ding stream, Waeng district, Narathiwat Prov., 5.935067°N, 101.909300°E, alt. 20 m., 21-IV-2018, B. Boonsoong leg. ( ZMKU); 8 larvae (in ethanol), Chan Ta Then waterfall, Sri Racha, Chonburi Prov., 13.242400°N, 101.044200°E, alt. 162 m, 6-VI-2018, B. Boonsoong leg. ( ZMKU); 3 larvae (in ethanol), Punyaban waterfall, Thannon Phet Kasem, Ranong Prov., 10.065066°N, 98.670183°E, alt 52 m, 19-IV-2018, B. Boonsoong leg. ( ZMKU).

Head. Labrum expanded laterally, ca. 4.2 times larger than long, with rounded apexes; dorsal surface and anterior margin covered with long and thin setae. Crown of the galealacinia of the maxillae with ca.18–20 comb-shaped setae. Right mandible with 7–8 fimbriate setae below the inner incisor and ca. 5–7 long simple and thin setae below the mola. Left mandible with 9–10 fimbriate setae below the inner incisor and ca. 4–5 long, simple and thin setae below the mola. Hypopharynx with robust lingua bearing a tuft of small setae, superlinguae densely covered with long and thin setae up to the lower part of the superlinguae. Labium with glossae rhomboid slightly concave in their inner and outer margins near apex ( Figure 6 (c)).

Thorax. Pronotum greatly expanded laterally and posteriorly, and basally fused to the mesonotum ( Figure 3 (a–b)). Femora with submarginal rows of pointed bristles on the inner and outer margins, increasing in numbers from the fore to the hind leg. Bristles on the dorsal surface of the hind femora with subparallel or slightly convergent margins, apexes rounded or truncate ( Figure 7 (c)). Hind tibia with one row of thin setae and a row of 5–7 arrow-shaped bristles in the marginal or submarginal position. Tarsal claw with 3–4 teeth ( Figure 9 (c)).

Abdomen. Posterolateral expansion not developed on segment I–II, weakly developed on segment III, strongly developed on segment IV and increasing in size up to VIII and divergent with the body ( Figure 3 (c)). Gill I with asymmetrical elongated and rounded plate, 2 times longer than wide ( Figure 10 (c)). Gill II–VI strongly asymmetrical, wider than long. Gill VII oval and almost symmetrical. Posterior margin of tergites with irregularly pointed teeth, and numerous microdenticle rows ( Figure 11 (c)). Cerci pale yellow with 3–4 dark brown bands increasing in size towards apex.

Figures

Figure 3. Thalerosphyrus vietnamensis (Dang, 1967). (a) Habitus in dorsal view. (b) Habitus in ventral view. (c) Detail of abdominal segments VI–IX in ventral view.

Figure 6. Labial glossa. (a) Thalerosphyrus flowersi (arrow show clearly concave near apex). (b) Thalerosphyrus sinuosus. (c) Thalerosphyrus vietnamensis. (d) Thalerosphyrus thailandensis sp. nov.

Figure 7. Bristles on the dorsal face of the hind femur. (a) Thalerosphyrus flowersi. (b) Thalerosphyrus sinuosus. (c) Thalerosphyrus vietnamensis. (d) Thalerosphyrus thailandensis sp. nov.

Figure 9. Tarsal claw. (a) Thalerosphyrus flowersi. (b) Thalerosphyrus sinuosus. (c) Thalerosphyrus vietnamensis. (d) Thalerosphyrus thailandensis sp. nov.

Figure 10. Gill I. (a) Thalerosphyrus flowersi. (b) Thalerosphyrus sinuosus. (c) Thalerosphyrus vietnamensis. (d) Thalerosphyrus thailandensis sp. nov.

Figure 11. Posterior margin of the abdominal tergite IV. (a) Thalerosphyrus flowersi. (arrow show numerous row of microdenticles). (b) Thalerosphyrus sinuosus. (c) Thalerosphyrus vietnamensis. (d) Thalerosphyrus thailandensis sp. nov. (arrow show a few row of microdenticles).