Huosoma tinctipenne (McLachlan, 1894)

Yang, Guo-Hui, Orr, Albert G. & Zhang, Hao-Miao, 2022, Descriptions of the larvae of Huosoma Guan, Dumont, Yu, Han & Vierstraete 2013 from China (Odonata: Coenagrionidae), Zootaxa 5134 (3), pp. 426-434 : 429-431

Huosoma tinctipenne (McLachlan, 1894)

( Figs 2b ; 4a–m ; 6 ; 7d–e )

Material examined: 1♀, larva, 1.V.2019, Haicang Village , Jiuzhou Town, Yunlong County (25.30°N, 99.02°E, 2,550 m a.s.l.), Dali City, Yunnan Province, China, Guo-Hui Yang leg. , 1♀, 1♂ larvae, 6.VI.2021, same locality, Guo-Hui Yang leg. 1♀ larva was successfully raised to emergence.

Habitus: Generally similar to H. latiloba . Legs and wing sheaths relatively slightly longer ( Figs 7d, e ) and, caudal lamellae leaf shaped, longer and narrower than in H. latiloba .

Head. Comparatively large, occipital lobes gently rounded, not bulbous in dorsal view; mouthparts ( Figs 4a–i ), fairly similar to H. latiloba but with relatively broader prementum, maximum breadth ca 0.78 length; length about four times wider than base; anterior margin more strongly projected as obtuse isosceles triangle, apex forming 105° angle (dorsal view), with fine marginal denticles; row of four long, strong setae sub-medially on upper side of prementum. Labial palp long and narrow, distinctly expanded apically, upper margin with six very long, strong setae set in raised tooth-like sockets ( Figs 4b, c ); movable hook short, incurved, only ca 1/2 length of longest palpal seta; palp terminating in broad securiform ‘comb’ separated by shallow notch from short ventral hook slightly exceeding margin of comb in length ( Fig. 6 ).

Thorax. Very similar to H. latiloba but legs longer; femur of hind leg reaching to hind margin of S4; outer wing sheaths reaching just beyond hind margin of S4, inner sheaths slightly shorter ( Figs 7d–e ).

Abdomen. Very similar to H. latiloba but ovipositor of female extending only to end of S10 ( Figs 4j–k ). Caudal lamellae foliate, long and narrow, more than half length of abdomen (maximum length 3.5 times width of lateral lamella and 3.2 times width of median lamella ( Figs 4l–m ). Lateral lamellae white-tipped with short terminal filament, also present in median lamella but less developed.

Measurements (mm). Larvae (N=3), body length (excluding caudal lamellae) 11.5–14; length of abdomen (excluding caudal lamellae) 7.5–8; maximum head width 2.8–2.9; length of hind femur 3.6–4; lateral caudal lamella 4.5–5.

Biological notes. The larvae of H. tinctipenne were found in a small, heavily vegetated shallow pond in a brook at an elevation of approximately 2,550 m ( Fig. 8b ). Adults were often present breeding in the same pond ( Fig. 7f ). The flight season ranges from June to September.

Figures

FIGURE 2. Heads of larvae of two species of Huosoma in dorsal view. (a) H. latiloba; (b) H. tinctipenne.

FIGURE 4. Morphological details of the final stadium larva of H. tinctipenne: (a) prementum, ventral view; (b) same, dorsal view; (c) right labial palp, inner surface; (d) right mandible, posterior view; (e) same, inner surface; (f) left mandible, posterior view; (g) same, inner surface; (h) right maxilla; (i) left maxilla; (j) female ovipositor, ventral view; (k) S8–10 of female, one of lateral lamella absent, lateral view; (l) lateral lamella, lateral view; (m) median lamella, lateral view.

FIGURE 6. Labial palp of Huosoma tinctipenne: left, anterior view in situ on prementum; right, showing detail, (a) inner length of comb; (b) width of comb; (c) palpal hook (measurement terminology corresponding with Brochard & van der Ploeg 2013).

FIGURE 7. Larvae and adults of two Huosoma species: (a) male larva of H. latiloba; (b) emerging adult male of H. latiloba; (c) mating pair of H. latiloba, Mt. Cangshan, Dali City, Yunnan Province (photo by Guo-Hui Yang); (d) larva of H. tinctipenne ready to feed on the larvae of Chironomidae; (e) final stadium larva of H. tinctipenne; (f) adult female of H. tinctipenne, Yunlong County, Dali City, Yunnan Province (photo by Guo-Hui Yang).

FIGURE 8. Habitats of the larvae of two Huosoma species in Yunnan: (a) H. latiloba; (b) H. tinctipenne.