Clypeocaenis oligosetosa Soldán, 1983

Vannachak, Viengkhone, Malzacher, Peter & Sangpradub, Narumon, 2024, Contribution to the genus Clypeocaenis Soldán, 1978 (Ephemeroptera: Caenidae) from Lao People’s Democratic Republic with a key to Oriental species, Zootaxa 5501 (4), pp. 501-523 : 510

publication ID	https://doi.org/ 10.11646/zootaxa.5501.4.1
publication LSID	lsid:zoobank.org:pub:29E9284E-6F5C-46E5-BA25-B54F820BE0C0
DOI	https://doi.org/10.5281/zenodo.13745369
persistent identifier	https://treatment.plazi.org/id/03F55817-FFA4-FFC6-FF6D-FCC7FD36F8D4
treatment provided by	Plazi
scientific name	Clypeocaenis oligosetosa Soldán, 1983
status

Treatment

Clypeocaenis oligosetosa Soldán, 1983 View in CoL ( Figs. 6–8 View FIGURE 6 View FIGURE 7 View FIGURE 8 )

Clypeocaenis oligosetosa Soldán, 1983: 198 View in CoL (orig. desc., Figs 2 View FIGURE 2 , 4 View FIGURE 4 , 6–7 View FIGURE 6 View FIGURE 7 , 12–14 View FIGURE 12 View FIGURE 13 View FIGURE 14 , 16, 18, 19–25; Martynov and Palatov, 2017: 1 Figs 1–10 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 ).

Materials examined. 5 male and 5 female larvae (THNHM-I-00029770–00029779), Lao PDR, Khammouane Province , Xebangfai District, Xe Nou River, 17°4’5.56”N, 105°4’13.68’’E, 154 m a.s.l., 6.I.2022, V. Vannachak leg, deposited in the Natural History Museum, Thailand GoogleMaps . 10 male and 14 female larvae (Cl/ Laos.004), same data deposited in KKU-AIC GoogleMaps . 20 male and 20 female larvae ( Cl / Laos.004), same data deposited in NUoL-AIC, all V. Vannachak leg. GoogleMaps

Egg: Oval shape, with 119–142 μm in length and 69–90 μm in width. Chorion smooth with a cap-shaped epithema. Micropyle, positioned subequatorially, moderate length, sperm guide not visible ( Fig. 7F, G View FIGURE 7 ).

Remarks. Clypeocaenis oligosetosa was initially recorded in Vietnam ( Soldán, 1983). Martynov and Palatov (2017) later extended its known distribution to Thailand, marking a significant range expansion of over 1300 km from the original locus typicus. This extension led to the anticipation of its presence in Lao PDR, which was confirmed by the specimens collected in this study. The identification of Cl. oligosetosa from Lao PDR was based on a distinct combination of morphological traits, such as the setae on the clypeal protrusion with several long setae (about 4) and several short ones ( Fig. 6A View FIGURE 6 ), maxillary palp two segmented, labial palp with a short and irregularly trapezoidal second segment, and an elongated third segment ( Fig. 6D, F View FIGURE 6 ), forefemur setation, operculate gill structure, and the microtrichia band pattern on the ventral side of the operculate gill with single spines, spine clusters, and a few irregularly scale-shaped microtrichia, positioned closer to the lateral margin ( Figs. 8B View FIGURE 8 , 12B View FIGURE 12 ).

The current investigation revealed the presence of shield-shaped microtrichia with fringed margins on the dorsal body surface, notably on the operculate gill ( Fig. 8A View FIGURE 8 ). The microtrichia band on the ventral side of the operculate gill closely follows the lateral margin, terminating well before the hind margin. This band is composed of slender spines and a few clusters of 2 or 3 spines, predominantly located along the inner margin of the band ( Figs. 8B View FIGURE 8 , 12C View FIGURE 12 ). Eggs extracted from mature female larvae are described here for the first time.

Distribution and habitat. Khammouane Province, Lao PDR ( Figs. 13A View FIGURE 13 , 14 View FIGURE 14 ). Cl. oligosetosa was collected within the littoral zone of the Xe Nou River.