Scheldt species source details
Kompoot, K. & S. Watiroyram. (2025). Freshwater copepods in the tributaries of the lower Mekong River Basin in Thailand. Biodiversitas. 26(4):1846-1859.
508356
10.13057/biodiv/d260434 [view]
Kompoot, K. & S. Watiroyram.
2025
Freshwater copepods in the tributaries of the lower Mekong River Basin in Thailand.
Biodiversitas
26(4):1846-1859.
Publication
Available for editors

The study of copepod species diversity exclusively in the Mekong River Basin of Thailand has been sporadic,
with no relevant publications for over a decade. Additionally, cyclopoid taxonomy remains a serious issue. This study investigated the
species composition and distribution of copepods in three river basins of the Mekong River in Thailand: the Mekong, Songkhram, and
Mun River Basins. Samples were qualitatively collected using a 60-μm plankton net during the monsoon rainy season by dragging the
net from the limnetic zone to the littoral zone. A total of 47 species were identified from 480 samples collected across various
waterbodies between 2020 and 2023 in seven provinces within the Mekong River Watershed, including Nong Khai, Bueng Kan, Udon
Thani, Sakon Nakhon, Nakhon Phanom, Amnat Charoen, and Ubon Ratchathani. Among 27 calanoid and 20 cyclopoid species, one new
cyclopoid species was named and published in prior research, and one new calanoid species is currently being prepared for the
nomenclature process. Two cyclopoid copepod species were newly recorded in Thailand: Mesocyclops woutersi and Microcyclops
pachyspina. We confirmed the presence of Microcyclops karvei in the country after its previous status had been uncertain. Furthermore,
at least three calanoid species previously recorded in the study area: Mongolodiaptomus uenoi, Neodiaptomus songkhramensis, and
Phyllodiaptomus christineae were not observed, suggesting their rarity, potential disappearance, or possible taxonomic
misidentification. Similar to cyclopoid copepods, additional sampling and taxonomic study are required for confirmation. The species
diversity and species list have been updated, and a brief morphological description along with taxonomic notes are provided for the two
newly recorded species and one rare species of cyclopoid copepods.
Keywords: Mesocyclops woutersi, Microcyclops karvei, Microcyclops pachyspina, new record, species list
Thermocyclops crassus (Fischer, 1853) accepted as Thermocyclops crassus crassus (Fischer, 1853) (additional source)