Lasiosmylus Ren & Guo, 1996

Zheng, Bingyu, Ren, Dong & Wang, Yongjie, 2016, A new species of Lasiosmylus from the Early Cretaceous, China clarifies its genus-group placement in Ithonidae (Neuroptera), ZooKeys 636, pp. 41-50 : 43-46

Genus Lasiosmylus Ren & Guo, 1996

Type species.

Lasiosmylus newi Ren & Guo, 1996.

Species included.

Lasiosmylus newi Ren & Guo, 1996, Lasiosmylus longus sp. n.

Amended diagnosis.

Body stout (ca. 11-17 mm long), covered with dense setae; head hypognathous, protruding from pronotum partly; antenna filiform (ca. 2-5 mm, incompletely preserved); compound eye large, ocelli absent; thorax robust, long setae concentrated on pronotum. Forewing ca. 12-23 mm long, 5-8 mm wide, membranous area with many fuscous spots; humeral plate distinct; dense setae along the veins, especially on the wing margin; trichosors and nygmata undetectable; costal space dilated basally and narrowed distally; humeral veinlet recurrent, with several simple branches; costal cross-veins simple, moderately curved distally in the apical half of the costal space; Sc and R1 separate distally, entering the margin before the wing apex; one or two sc-r1 crossveins; R1 with four to eleven pectinate branches distally; the origin of Rs distant from the wing base, with seven to thirteen branches regularly arranged; relatively few crossveins present in radial area; MA simple, dichotomously branched terminally; MP first fork distant from wing base. Hind wing ca. 11-18 mm long, 4-8 mm wide, partly preserved, venation similar to forewing except for the following characters: costal space narrow, only slightly expand in proximal portion.

Remarks.

Lasiosmylus shows a superficial similarity with osmylids, sharing plesiomorphic features such as the fork of MP in forewing usually between the separation of MA and first Rs branch, sometimes opposite the separation of MA; wings not falcate, with few crossveins ( Ren and Guo 1996). However, all these characters do not well support the assignment of Lasiosmylus to Spilosmylinae, or Osmylidae in general because they also frequently occur in other families (e.g., Ithonidae , Berothidae , some Mantispidae ). The subsequent transfer to Ithonidae by Makarkin et al. (2012, 2014) seems reasonable; moreover, recently it was classified further as belonging to the polystoechotid genus-group by Zheng et al. (2016).

Herein, nine new-collected specimens are examined in this study. All these specimens are placed in Lasiosmylus based on the following characters: numerous dispersed spots on the forewing, simple costal crossveins, two subcostal crossveins, Rs less than ten branches (about six to eight branches), MP distant from the wing base and beyond MA fork, MP1 and MP2 simple, one mp1-mp2 crossvein, CuA dichotomously branched distally (in particular, obs. CNU-NEU-LB2015001P/C and CNU-NEU-LB2015002, see Figs 1, 2; and Ren and Guo 1996: fig. 5, fig. 10, pl. 3, fig. 11, pl. 2). Noticeably, during checking the specimens, we found some variable characters that are distinctly different from the type specimen, e.g., humeral veinlet and separated Sc and R1. A recurrent humeral veinlet is considered as a synapomorphy for Ithonidae ( Yang et al. 2012, Makarkin et al. 2013, Zheng et al. 2016). However, this character is absent in the line drawing of Lasiosmylus newi ( Ren and Guo 1996: fig. 5), although some trace of recurrent humeral veinlet can be detected in the photograph of Lasiosmylus ( Ren and Guo 1996: fig. 11, pl. 4). Regretfully, the holotype of Lasiosmylus newi was not available for examination during this study (possibly lost). However, it is reasonable to assume now that the recurrent humeral veinlet occurs in Lasiosmylus newi according to these new specimens.

In addition, the distally separated Sc and R1 were regarded as a synapomorphic character of Ithonidae ( Zheng et al. 2016). In the original illustration of Lasiosmylus newi , Sc and R1 were drawn with fused termination. Unfortunately, the photograph of Lasiosmylus newi is too obscure for us to discern the condition of Sc and R1 ( Ren and Guo 1996: fig. 10, pl. 3, fig. 11, pl. 2). In extant members of the polystoechotid genus-group Sc and R1 are closely approximated but are actually not fused, e.g., Fontecilla Navás, 1931, Platystoechotes Carpenter, 1940, Polystoechotes Burmeister, 1839 (see Winterton and Makarkin 2010). While this character was not fully investigated in the fossil lineages, most fossil polystoechotid genera were illustrated with the fused Sc and R1.

During the examination of the new materials, it is clear that all specimens assigned to Lasiosmylus (Figs 1, 2) show a separate Sc and R1. Furthermore, nine specimens (CNU-NEU-LB2015001P/C, CNU-NEU-LB2015002, CNU-NEU-LB2016001P/C, CNU-NEU-LB2016002, CNU-NEU-LB2016003, CNU-NEU-LB2016004, CNU-NEU-LB2016005, CNU-NEU-LB2016006, CNUNEU-LB2016007) exhibit the typically venation with Lasiosmylus newi with exception for the incompatible conditions of Sc and R1. These nine specimens are considered to be Lasiosmylus newi .

It is concluded here that the genus Lasiosmylus most commonly has the separated Sc and R1 that is consistent with other moth lacewings. The exception of Sc and R1 in the holotype of Lasiosmylus newi possibly represents a particularly individual variation, inaccuracy in line drawing or obscurity in the specimen. Based on this we consider Lasiosmylus is unquestionably assigned to the ithonid genus-group by the following combination of characters: robust and hairy body, retracted head under pronotum, costal space dilated basally and narrowed disproportionately distally, separated Sc and R1 reaching the anterior margin straightly before the wing apex, MP first fork distant from the wing base and beyond the divergence of MA.