Sialis

Liu, Xingyue, Hayashi, Fumio & Yang, Ding, 2009, Sialis navasi, a new alderfly species from China (Megaloptera: Sialidae), Zootaxa 2230, pp. 64-68 : 65

Key to adults of Sialis from China

1. Apex of abdomen posteriorly modified as a complicated assemblage of parts, ninth sternum present (male)............ 2

- Apex of abdomen gradually narrowed posteriad, ninth segment without ninth sternum ventrally, but leaving a pair of broad and membranous ninth gonocoxite (ovipositor) (female)................................................................................... 9

2. Pronotum mostly or entirely black................................................................................................................................ 3

- Pronotum entirely orange or yellowish brown ............................................................................................................. 4

3. Ninth tergum roundly inflated laterally in dorsal view ( Fig. 3 ); tenth tergum compactly fused with eleventh gono- coxite ( Fig. 5 ) ...................................................................................................................................... S. navasi sp. nov.

- Ninth tergum convexed posteriad in dorsal view, without any lateral inflation; tenth tergum and eleventh gonocoxite apparently separated from each other as two independent structures........................................................................... 4

4. Ninth sternum broadly subtrapezoidal, much longer than ninth tergum ( Liu & Yang 2006a: Fig. 11).......................... .............................................................................................................................................................. S. kunmingensis

- Ninth sternum transversely band-like, much shorter than ninth tergum....................................................................... 5

5. Ninth gonocoxite large, about 1.5 times as long as ninth tergum ( Liu & Yang 2006b: Fig. 4 a); eleventh gonocoxite reduced into a pair of extremely small and simply unguiform processes ( Liu & Yang 2006b: Fig. 4 a) ........ S. sibirica

- Ninth gonocoxite small, shorter than ninth tergum; eleventh gonocoxite large, with proximal portion expanded later- ally to some degree ( Liu & Yang 2006b: Fig. 3 b) ........................................................................................................ 6

6. Tenth tergum strongly narrowed into a somewhat curved projection ventrad ( Liu & Yang 2006a: Fig. 15)................. ....................................................................................................................................................................... S. sinensis

- Tenth tergum ventrally without strongly narrowed projection ( Liu & Yang 2006b: Figs. 2 b, 3b)............................... 7

7. Eleventh gonocoxite with proximal expansion separated into two pairs of short and slender lobes ( Liu & Yang 2006b: Figs. 2 b) ........................................................................................................................................ S. henanensis

- Eleventh gonocoxite with proximal expansion as a pair of broad and pterygoid lobes ( Liu & Yang 2006b: Figs. 3 b .. .................................................................................................................................................................... S. longidens

8. Tenth tergum long ( Liu & Yang 2006a: Fig. 7); eleventh gonocoxite medially with a pair of subtriangular expansions ( Liu & Yang 2006a: Figs. 7–8) ....................................................................................................................... S. elegans

- Tenth tergum short ( Liu & Yang 2006a: Figs. 17, 18); eleventh gonocoxite medially with a pair of subquadrate expansions ( Liu & Yang 2006a: Fig. 19) ................................................................................................. S. versicoloris

9. Pronotum entirely black.............................................................................................................................................. 10

- Pronotum entirely orange or yellowish brown ............................................................................................................. 6

10. Eighth sternum transversely band-like, nearly 4.0–5.0 times as wide as long ( Liu & Yang 2006b: Figs. 4 d)........... 11

- Eighth sternum broad, nearly 3.0 times as wide as long ( Liu & Yang 2006a: Fig. 16).............................................. 12

11. Eighth sternum anteriorly with a deep median incision ( Liu & Yang 2006b: Figs. 4 d) ................................. S. sibirica

- Eighth sternum anteriorly without distinct median incision ( Hayashi & Suda 1995: Fig. 5 e) ................... S. longidens

12. Eigth sternum anteriorly truncate, medially with a rather narrow longitudinal depression ( Liu & Yang 2006b: Figs. 4 d) .................................................................................................................................................................. S. sinensis

- Eighth sternum anteriorly concaved, medially with a borad longitudinal depression ( Liu 2008: Fig. 107d) ................ .................................................................................................................................................................. S. henanensis

13. Wings narrow, about 1/3 of length ( Liu & Yang 2006a: Fig. 2 ) ............................................................ S. jianfengensis

- Wings broad, about 1/2 of length ( Liu & Yang 2006a: Figs. 1 , 6 ) ............................................................................... 7

14. Head orange; eighth sternum with anterolateral portion prominent ( Liu & Yang 2006a: Fig. 20) ......... S. versicoloris

- Head black; eighth sternum with anterolateral portion not prominent ( Liu & Yang 2006a: Fig. 9) .............. S. elegans

Figures

FIGURE 1. Habitus image of Sialis navasi sp. nov. (holotype), male. Scale bars = 1.0 mm.

FIGURES 2 – 6. Sialis navasi sp. nov., male. 2. Male head and prothorax, dorsal view; 3. Genitalia, dorsal view; 4. Genitalia, ventral view; 5. Genitalia, lateral view; 6. Genitalia, caudal view. g 9: ninth gonocoxite; g 11: eleventh gonocoxite; s 9: ninth sternum; t 9 – 10: ninth to tenth tergum. Scale bars = 0.25 mm.