Labiobaetis diffundus ( Müller-Liebenau, 1984 ) Muller-Liebenau, 1984

Shi, Weifang & Tong, Xiaoli, 2014, The genus Labiobaetis (Ephemeroptera: Baetidae) in China, with description of a new species, Zootaxa 3815 (3), pp. 397-408 : 401-403

Labiobaetis diffundus ( Müller-Liebenau, 1984) n. comb.

( Figs. 16–19 )

Baetis diffundus: Müller-Liebenau, 1984: 261 ;

Labiobaetis diffundus: McCafferty & Waltz, 1995: 21 ; Pseudocloeon diffundum: Lugo-Ortiz et al., 1999: 24

Specimens examined (in ethanol). CHINA, Hunan Province, 1 nymph on slide and 3 nymphs, Linxiang County, Longyuan Town (29.44°N, 113.70°E), 20-v-2002, coll. Wang Wenli; Yunnan Province: 4 nymphs, Mengla County, Menglun Town, Baka hydropower station (21.97°N, 101.20°E), 22-ix-2003, coll. Tong Xiaoli; 1 nymph on slide and 1 nymph, Dali City, Yangbi County, Cangshan, Yangbijiang River (25.51°N, 99.98°E, alt. 2600m), 10-xii-2012, coll. Zhang Haomiao; Guizhou Province: 2 nymphs, Daozhen County, Sanqiao Town (29.16°N, 107.43°E, alt. 1370m), 21-viii-2004, coll. Wang Jun; 1 nymph on slide and 1 nymphs, Daozhen County, Dashahe Nature Reserve (29.17°N, 107.4°E, alt. 1050m), 25-viii-2004, coll. Wang Jun; 1 nymph on slide and 13 nymphs, Chishui City, The Jurassic Park of China (28.45°N, 105.99°E, alt. 376m), 31-iii-2012, coll. Shi Weifang; 1 nymph on slide, Chishui City, Foguangyan Park (28.40°N, 105.95°E, alt. 310m), 31-iii-2012, coll. Shi Weifang; Guangxi: 16 nymphs, Maoershan National Nature Reserve, Jiuniutan (25.85°N, 110.47°E, alt. 1132m), 22-vii- 2003, coll. Tong Xiaoli; 56 nymphs, Maoershan National Nature Reserve, Laoshanmen (25.90°N, 110.43°E, alt. 1738m), coll. Tong Xiaoli; 2 nymphs on slides and 8 nymphs, Jinxiu County, Dayaoshan National Nature Reserve (24.12°N, 110.21°E, alt. 779m), 16-xi-2011, coll. Shi Weifang; Hong Kong: 6 nymphs, Shing Mun (22.39°N, 114.15°E, alt. 187m), 7-i-1997, coll. Tong Xiaoli; 4 nymphs, Tai Po Kau Forest Stream (22.43°N, 114.18°E, alt. 168m), 13-xi-1997, coll. Tong Xiaoli; Hainan Province: 6 nymphs, Baiji Town, Yinggeling National Nature Reserve (19.04°N, 109.56°E, alt. 600m), 23-xi-2005, coll. Yao Haiyuan.

Distribution. China (Hunan, Yunnan, Guizhou, Guangxi, Hong Kong, Hainan, Taiwan), Malaysia.

Remarks. L. diffundus (Müller-Liebenau) was first established by Müller-Liebenau in 1984 from Malaysia ( Müller-Liebenau 1984). Later, Müller-Liebenau & Hubbard (1985) described L. geminatus (Müller-Liebenau & Hubbard) as new species from Sri Lanka and they suggested both species should probably be considered sibling species and belong to the Oriental molawinensis species-group ( Müller-Liebenau & Hubbard 1985). L. geminatus appears to be most closely related to L. diffundus as both species possesses an unusual characteristic within the Oriental species, i.e. the submarginal setae on labrum is spatulate with un-serrated apex ( Fig. 16 ), however, the 3rd segment of the labial palpus in L. geminatus is wider than the inner apical lobe of the 2nd segment, whereas in L. diffundus , is of nearly the same width as the inner apical lobe of the 2nd segment; the paraproct of L. geminatus is much longer than that of L. diffundus ( Müller-Liebenau & Hubbard 1985) . It is also not easy to separate L. diffundus from L. molawinensis (Müller-Liebenau) because both species have six pairs of gills, antennal scape with a small lateral lobe at distolateral margin and hind wing pads are absent, but the submarginal spatulate setae on labrum serrated distally in L. molawinensis . Kang et al. (1994) reported that L. molawinensis has been found in Taiwan, however, according to their illustrations (see Kang et al. 1994 figs. 15 and 28), the submarginal setae on labrum and color pattern of abdominal terga of the Taiwanese specimens are apparently the same with the original illustrations and descriptions of L. diffundus (see Müller-Liebenau 1984 figs. 6 and 21). We have not examined this Taiwanese specimen, but judging from the illustrations and descriptions by Kang et al. (1994), it actually should be L. diffundus which was misidentified as L. molawinensis .

Figures

FIGURES 16 – 19. Labiobaetis diffundus (Müller-Liebenau). 16, labrum (showed the un-serrated submarginal setae apically on labrum); 17, pronotum; 18, color pattern of abdominal terga; 19, habitus of female nymph.