Megabranchiella longusa Phlai-ngam & Tungpairojwong 2022
Creators: name: Tong, Xiaoli
name: Zhou, Zhiheng
name: Wu, Bangyi
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Baetidae
Megabranchiella
Megabranchiella longusa

description: Megabranchiella longusa Phlai-ngam & Tungpairojwong, 2022
Figs 18, 19, 20, 21
Megabranchiella longusa: Phlai-ngam & Tungpairojwong in Phlai-ngam et al. 2022: 16.
Material examined.
One female larva on slide; Yunnan, Lushui, Bajiao River (a tributary of the Nujiang River, altitude 1112 m); 21. iii. 2019; leg. Xiaoli Tong.
Diagnosis.
Female larva (Fig. 18 a – d), body short and flattened, length ~ 4.0 mm; body colour pattern as Fig. 18 a – c. Head. Labrum nearly semicircular, ~ 1.4 × wider than long; anteromedian notch deep with a small, rounded lobe at base; dorsal surface in distal 1 / 2 with one pair of long, simple setae near midline and irregular row of three medium, simple setae (Fig. 19 c). Left mandible (Fig. 19 a), incisor and kinetodontium fused, incisor with four denticles, kinetodontium with six denticles decreasing in length, prostheca robust, apex with six bluntly denticles and one or two long, spine-like denticles; incisor of right mandible with four denticles, kinetodontium with four denticles, inner margin of innermost denticle with row of small denticles; prostheca robust, apex with comb-like structure, with many denticles apically (Fig. 19 b). Maxilla (Fig. 19 e), galea-lacinia of with three robust canines, base of lacinia with one row of four long, simple setae and one seta perpendicular to lacinia margin; maxillary palp 2 - segmented, apex of segment II with a small cone-shaped projection. Labium (Fig. 19 d, f), glossae shorter and narrower than paraglossae, paraglossae with three rows of long curved setae distoventrally, dorsal surface on distal 1 / 2 with one longitudinal row of two or three long, spine-like setae near inner margin; labial palp 3 - segmented, segment I longer than segments II and III combined, segment II triangular with small protuberance apico-laterally, dorsal surface of segment II with row of two robust, simple setae near distal margin (Fig. 19 g). Thorax. Hindwing pads reduced (Fig. 20 b). Forelegs (Fig. 21 c), femur with a row of long, robust, pointed setae along dorsal margin, surface with notched scales anteromedially (Fig. 20 c), villopore present (Fig. 20 d); tibia with a row of long, pointed setae and short, blunt spatulate setae, tibio-patellar suture present; ventral margin of tarsus with one row of four robust, spine-like setae; claws hooked (Fig. 21 b) with one row of 13 acute teeth, subapical setae absent. Middle and hind legs similar to foreleg in structure. Abdomen. Abdominal tergites and sternites with smooth posterior margins (Fig. 21 a); gills present on abdominal tergites I – VII, gill I oriented ventrally, extremely enlarged and elongated (Fig. 20 a), covering abdominal sternites II – VI (Fig. 18 c), gills II – VII oriented dorsolaterally, elongated oval similar to tongue blade (Figs 18 c, 20 a), gill margins with long, fine, hair-like setae, ratio of gill length from I – VII = 3.2: 1.7: 1.7: 1.7: 1.5: 1.3: 1.0; paraproct with smooth margin, without marginal spines or spatulate setae, surface with micropores and patch of notch scales (Fig. 21 d, e).
Distribution
(Fig. 23). Thailand (Chiang Mai and Nan Provinces) and China (Yunnan Province).
Larval habitat
(Fig. 22 c). The species was collected in a swift, unshaded stream with cobble substrate at an altitude of ~ 1100 m in Yunnan, China.
Remarks.
Geographically, this record represents the farthest distribution north of the genus Megabranchiella so far. We expect that more species of the genus will be discovered with the expansion of the investigation range in China.
description: Published as part of Tong, Xiaoli, Zhou, Zhiheng & Wu, Bangyi, 2024, First contribution to the genera Branchiobaetis and Megabranchiella (Ephemeroptera, Baetidae) in China, with descriptions of two new species, pp. 115-148 in ZooKeys 1216 on pages 115-148, DOI: 10.3897/zookeys.1216.129803