Sialis navasi, Liu, Xingyue, Hayashi, Fumio & Yang, Ding, 2009

Liu, Xingyue, Hayashi, Fumio & Yang, Ding, 2009, Sialis navasi, a new alderfly species from China (Megaloptera: Sialidae), Zootaxa 2230, pp. 64-68 : 66-67

Sialis navasi sp. nov.

( Figs. 1–6 )

Diagnosis. This species is much smaller than the other known species of Sialis from China. Other important characters include the narrowed forewings, the male ninth tergum being distinctly inflated laterally, and the ninth gonocoxite being strongly narrowed posteromesally into a rounded, digitiform process.

Male. Body length 6.5–6.7 mm (n=2); forewing length 8.1–9.1 mm, hindwing length 7.2–8.4 mm.

Head ( Fig. 2 ) black, with dense pale pilosity; frons with a pair of yellowish brown, round spots; vertex medially with a pair of raised yellowish brown vittae and laterally with several raised yellowish brown stripes and round spots. Compound eyes dark. Antennae dark brown. Mouthparts dark brown, with labrum black.

Thorax blackish brown; pronotum ( Fig. 2 ) black, laterally with indistinct trace of arcuate yellowish brown markings. Legs dark brown, bearing dense pale setae; tarsal claws reddish brown. Wings ( Fig. 1 ) somewhat narrow, slightly smoky brown; veins brown. Forewing nearly 3.5 times as long as wide, with 11 costal crossveins; sc–r absent; R1+2 2 or 3–branched, R3+4 2–branched, M1+2 simple, M3+4 bifurcate, Cu1 bifurcate, three crossveins between R1 and Rs. Hindwing slightly broader than forewing, about 3.0 times as long as wide; venations similar to forewing, with 8-10 costal crossveins.

Abdomen black, laterally with reddish brown markings. Ninth tergum ( Figs. 3, 5 ) in dorsal view nearly 1.5 times as wide as long, anterior margin slightly incised, posterior margin distinctly and arcuately incised, posterolaterally inflated roundly. Ninth sternum ( Figs. 4–6 ) rather short, transversely band-like, slightly depressed medially. Ninth gonocoxite ( Figs. 3–6 ) broad, anterodorsal portion slightly bent, posteromedially strongly narrowed into a digitiform process with tip rounded and lightly sclerotized. Tenth tergum ( Figs. 5–6 ) lightly sclerotized, fused posteriorly with eleventh gonocoxite. Eleventh gonocoxite ( Figs. 4–6 ) narrow, produced posteroventrad, distally with a pair of widely separated spinous processes.

Female. Unknown.

Immatures. Unknown.

Material examined. Holotype male, “Zo sé [E. China, Shanghai, Sheshan, 31°06'N, 121°11'E], 14.IV.1933, Savio [1st label, handwritten, yellow]”, “ Sialis japonica Weele , det. Navás S. J. [2nd label, handwritten with printed name of Navás S. J., yellow]” ( DEI). Paratype male, same data as holotype ( DEI).

Distribution. The type locality, Sheshan, is located very close to the metropolitan center of Shanghai, one of the largest cities in mainland China. This suggests that the type habitat for this new species may no longer exist. The species could be extincted; although, it may be located in suitable habitat in adjacent Jiangsu and Zhejiang Provinces.

Etymology. The new species is dedicated to the Spanish entomologist Longinos Navás, who worked extensively on worldwide Neuropterida in the early 20th Century.

Remarks. The new species is similar to Sialis sibirica McLachlan, 1872 and S. japonica based on the male ninth gonocoxite being strongly narrowed posteriorly into an obtusely tapered process. However, the new species is much smaller than either of these species. Additionally, it can be easily distinguished from the latter two species by the male ninth tergum being laterally inflated and by the compactly fused male tenth tergum and eleventh gonocoxite. In S. sibirica and S. japonica , the male ninth tergum is simply convex posteriorly without inflation and the male tenth tergum is distinctly separate from the eleventh gonocoxite. Although the sc–r of the forewings is absent in the holotype, it is present in the paratype, which is probably the typical state of this species.

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.