Stenolysmus Kimmins, 1940

Winterton, Shaun L., Martins, Caleb Califre, Makarkin, Vladimir, Ardila-Camacho, Adrian & Wang, Yongjie, 2019, Lance lacewings of the world (Neuroptera: Archeosmylidae, Osmylidae, Saucrosmylidae): review of living and fossil genera, Zootaxa 4581 (1), pp. 1-99 : 76-78

Stenolysmus Kimmins, 1940

( Figs 57–59 )

Type species. Nymphes extranea Walker, 1853: 230 (by original designation).

Diagnosis. Antennae elongate, ca. FW length; female forecoxa without pedicellate setae, anteroventral process absent; wings elongate, narrowly ovoid, hyaline with dark venation and pale pterostigma; costal area relatively narrow; FW stem of RP relatively short, RP1 originating close to origin of RP; RP branches weakly sinuous distally in both wings; end-twigging mostly irregular and multi-layered along posterior margin of wings; FW M fork just beyond midpoint of wing, MA and MP dichotomously or pectinately branched, M fork sometimes obscured as MP may be fused to CuA distally (when this occurs there is an apparent oblique ‘ m-cua crossvein’ (inset in Fig. 58 )); female with all FW veins regular, not incrassate; FW CuA and CuP not strongly arched towards posterior wing margin distally; A2 elongate, terminating more or less level with origin of RP1; male tergites 8 and 9 and ectoprocts mostly fused; ectoproct apically rounded; gonarcus large and subtriangular, lobed dorsally, anterior apodemes absent; entoprocessus short, broadly rounded; female sternite 7 with posteroapical corners produced; sternite 8 concave with rounded posterolateral processes with setal pile; gonapophysis 9 broadly lobed and truncate with internal sculpturing; gonocoxites 9 with distinct posteroventral fringe with stout hooked setae.

Comments. Stenolysmus extraneus is bright orange when living, and along with the unusual wing venation, was likely the reason for the original placement in Nymphes Leach by Walker (1853), a nymphid genus where many species are also bright orange in colour. Indeed, S. extraneus has been placed by various authors in Osmylidae (i.e., Osmylus sensu lato and Stenosmylus ) and Nymphidae (i.e., Nymphes , Myiodactylus Brauer ) (e.g., Walker 1853; Hagen 1866; McLachlan, 1867; Banks 1913). The unusual ‘oblique m-cua crossvein’ in the forewing of some individuals of various genera of Stenosmylinae , including some individuals of S. extraneus has created some confusion regarding the identity and homology of certain wing veins ( New, 1986; Cousins & Béthoux, 2015). New (1986) and Cousins & Béthoux (2015) studied the forewings of various genera of Stenosmylinae and proposed that the oblique crossvein in the forewing of some individuals represented a fusion of MP (as MP2) with CuA. Following the method of identifying wing veins in lacewings used recently by Breitkreuz et al. (2017) we examined the wing tracheation of different individuals of S. extraneus without ( Fig. 59 ) and with ( Fig. 59 , inset) the ‘oblique m-cua crossvein’ to identify veins and their points of apparent fusion. The forewing tracheation of both forms of S. extraneus clearly show that the oblique vein is indeed the stem of MP which fuses with CuA for a short length, and then separates again, supporting the contention that the oblique vein is the stem of MP and not a crossvein ( New, 1986; Cousins & Béthoux, 2015).

Figures

FIGURE 57. Stenosmylinae. Stenolysmus extraneus (Walker) (photo: Reiner Richter).

FIGURE 58. Stenosmylinae. Stenolysmus extraneus (Walker).

FIGURE 59. Stenosmylinae. Stenolysmus extraneus (Walker), wing venation (after Cousin & Béthoux, 2015) (vestiture omitted), alternative MP venation exhibited by some individuals shown as inset.