Research Article |
Corresponding author: Pongsak Laudee ( pongsak.l@psu.ac.th ) Academic editor: Ana Previšić
© 2021 Penkhae Thamsenanupap, Hans Malicky, Chanda Vongsombath, Pongsak Laudee.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Thamsenanupap P, Malicky H, Vongsombath C, Laudee P (2021) Three new species of caddisflies (Trichoptera, Hydroptilidae, Polycentropodidae, Leptoceridae) from Khon Phapheng Waterfall, the Mekong River, Laos. ZooKeys 1055: 149-159. https://doi.org/10.3897/zookeys.1055.66536
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The Mekong River is a hotspot area for freshwater biodiversity, but caddisfly diversity is largely understudied. Three new species of caddisflies from three different families are described and illustrated from Khon Phapheng Waterfall, the Mekong River, Laos; Orthotrichia choengthongi Malicky & Laudee, sp. nov. (Hydroptilidae), Pseudoneureclipsis khonphaphengensis Malicky & Thamsenanupap, sp. nov. (Polycentropodidae), and Setodes karrilai Malicky & Laudee, sp. nov. Orthotrichia choengthongi Malicky & Laudee, sp. nov. can be differentiated from the most similar Orthotrichia triton
Aquatic insects, biodiversity, Oriental Region, taxonomy
The Mekong River is one of the main rivers in Southeast Asia, flowing from the Tibetan Plateau through several countries to the South China Sea. A large human population in the Southeast Asian region depends on it as a source for subsistence (Campbell 2009;
Knowledge on species diversity of Trichoptera in Laos is very limited. Approximately two hundred Laotian caddisfly species have been recorded (
The aim of this research study was to describe new species of Trichoptera from the falls in the Mekong River, and thus to provide a valuable contribution to the knowledge on South-East Asian caddisfly diversity.
Adult stage caddisfly specimens were collected with a UV pan light trap (12 V, 10 W) set beside Khon Phapheng waterfall, Mekong River, at night. The caddisfly specimens were preserved in 70% ethanol. For identifying to species level, the male genitalia of the caddisflies were observed under a stereomicroscope. The male genitalia were dissected and the muscle tissues macerated by heating in 10% KOH at 60 °C for 30–60 minutes then soaked in a detergent solution before being transferred back to 70% ethanol. The genitalia of caddisflies were identified to species level after
Holotypes are preserved and stored in the Princess Maha Chakri Sirindhorn Natural History Museum, Prince of Songkla University, Hat Yai Campus, Hat Yai district, Songkhla province, Thailand (
Holotype. Male. Laos: Pakse Province: Champasak, Khonphapheng waterfall, Mekong River, 13°57'30"N, 105°59'14"E, elev. 64 m, 8.iv.2019, Pongsak Laudee. (
The new species is similar to Orthotrichia triton Malicky, 2008 from Borneo in the general shape of the male genitalia. However, it can be differentiated in that the shape of tergum X of Orthotrichia choengthongi Malicky & Laudee, sp. nov. is long and tubular, pointed apically and curved inwards then abruptly upwards in dorsal view; however, is stout basally then curved slightly downward in O. triton. Moreover, the united inferior appendages of the new species are collectively trilobed; but bilobed in O. triton.
Adult, male, length of each male forewing 1.6.–2.0 mm (n = 11); color in alcohol of head, thorax, forewings, abdomen, and legs light brown.
Male genitalia extremely asymmetric (Fig.
Orthotrichia choengthongi, sp. nov. Male genitalia A tergum IX and tergum X, dorsal B terga IX and X and inferior appendages, left lateral C terga IX and X and inferior appendages, right lateral D inferior appendages and paramere, ventral E phallus, left lateral. Abbreviations: Te IX = tergum IX, Pos = Posterolateral process (paired), Do = Doral spine, Te X = tergum X, Inf = united inferior appendages, Tu = Tubular processes, Par = Paramere.
The species epithet honors Asst. Prof. Dr Suchart Choengthong, Prince of Songkla University, Surat Thani Campus.
Holotype. Male. Laos: Pakse Province: Champasak, Khonphapheng waterfall, Mekong river, 13°57'30"N, 105°59'14"E, elev. 64 m, 8.iv.2019, Pongsak Laudee. (
The male genitalia of P. khonphaphengensis sp. nov. are similar to those of P. kaineus Malicky & Bunlue in
Adult, male, length of each male forewing 4.0–4.5 mm (n = 9); general body color in alcohol yellow brown.
Male genitalia as in Figure
The species is named for the type locality, Khon Phapheng waterfall.
Pseudoneureclipsis khonphaphengensis, sp. nov. Male genitalia A segment X, preanal appendages and intermediate appendages, dorsal B segments IX and X and inferior appendages, left lateral C inferior appendages, ventral D phallus, left lateral; the arrow shows hooked phallic sclerite, ventral E phallus, dorsal. Abbreviations: Seg IX = segment IX, Seg X = segment X, Pre = preanal appendages, Int = Intermediate appendage, Inf = inferior appendage (paired), Bas = basodorsal process of inferior appendage.
Holotype. Male. Laos: Pakse Province: Champasak, Khonphapheng waterfalls, Mekong river, 13°57'30"N, 105°59'14"E, elev. 64 m, 8.iv.2019, Pongsak Laudee. (
The male genitalia of S. karrilai sp. nov. are similar to those of S. omphale Malicky & Changthong in
Length of each male forewing 6.5–7.0 mm (n = 18); color in alcohol of head, thorax, forewings, and abdomen yellow; femora and tibiae brown or dark brown; wings clear and transparent, yellowish with brown veins.
Male genitalia as in Figure
The species epithet honors Assoc. Prof. Dr Seppo Karrila, Faculty of Science and Industrial Technology, Prince of Songkla University, Surat Thani Campus.
Setodes karrilai, sp. nov. Male genitalia A segment X, preanal appendages, dorsal B segments IX and X, preanal appendages, inferior appendages, left lateral C segment IX, inferior appendages, ventral D phallus, left lateral. Abbreviations: Seg IX = segment IX, Pre = preanal appendage (paired), Inf = inferior appendage (paired).
Three new species of caddisflies were described from Khon Phapheng waterfall, where the whole Mekong River drops 30 meters over the waterfalls. These species are Orthotrichia choengthongi sp. nov., Pseudoneureclipsis khonphaphengensis sp. nov., and Setodes karrilai sp. nov. The three new species are potamon species that live in large rivers. The substrate is dominated by bedrocks, boulders, and sand (Fig.
The genus Pseudoneureclipsis has been previously reported from Laos, i.e., six species were known; thus including P. khonphaphengensis sp. nov. there are now seven species of Pseudoneureclipsis recorded from Laos. In addition to the Laotian species, there are three species (P. romosa, P. usia and P. kaineus) with wider distribution in South-East Asia (
In addition to the description of a new species, for Setodes karrilai sp. nov. we give data on its distribution, as it was collected from several provinces in Laos, not only from the Khon Phapheng waterfall. Thus, it is a widespread species in the Mekong River, which is found from central to southern Laos. The genus Setodes is represented by twenty Laotian species, among the more than eighty species that have been reported from South-East Asia (
This research is supported by the Thailand Research Fund (TRF), project number DBG 6180021 and Prince of Songkla University, Surat Thani Campus. We thank Assoc. Prof. Dr Seppo Karrila for comments and linguistic assistance. We also thank Prof. Dr John C Morse, Prof. Dr Lianfang Yang and Dr Manpreet Singh Pandher for providing very useful suggestions to improve the manuscript.