SAUCROSMYLIDAE Ren & Yin, 2003

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 : 86-87

SAUCROSMYLIDAE Ren & Yin, 2003 (‘elegant lance lacewings’)

Type genus. Saucrosmylus Ren & Yin, 2003: 3 (by original designation).

Diagnosis. Antenna filiform, shorter than half of FW length; wings broad, ovoid to subtriangular, often with the posterior margin sinuate distally (in either wing) and often with distinct markings; costal area relatively narrow; nygmata present; venation dense with numerous longitudinal veins, veinlets and crossveins present; venation in FW and HW remarkably similar in the size and branching pattern of vein fields; end-twigging along posterior margin dense multi-layered and irregular; trichosors present apparently around entire wing margin; costal area relatively narrow, subcostal veinlets simple to forked, interlinked by crossveins; single basal subcostal crossvein present; Sc and RA fused apically and curved posterior to enter margin before wing apex; area between RA and RP wide, with 2–7 irregular rows of cells; RP divergent from RA in basal half of wing, convergent with RA distally; RP branches numerous, distal forking irregular and angled toward posterior margin of wing, occasionally with secondary vein fusion, branches slightly curved posteriorly in distal part of wing; gradate absent; FW M fork close to wing base, usually between origin of RP1 and RP2; MP pectinately branched, sometimes irregularly with extensive secondary branching; CuA pectinately branched (sometimes irregularly) in middle of wing, larger in area than CuP in both wings.

Comments. Saucrosmylidae is an extinct family of Mesozoic lance lacewings originally described as a subfamily of Osmylidae ( Ren & Yin, 2003) based on a series of symplesiomorphic characteristics found throughout Neuroptera . Of these, the most distinctive (although not necessarily unique to Saucrosmylidae ) is the presence of multiple irregular rows of cells between RA and RP. Although the wing shape may vary between the forewing and hind wing, the wings are remarkably homogeneous in vein branching pattern and the size of vein fields. The density of vein branching and crossveins is typical of distantly related families in Myrmeleontoidea (e.g., Kalligrammatidae ), although other families with such dense venation frequently have quite different branching patterns between the fore- and hind wings (i.e., various Myrmeleontoidea). Following the unpublished thesis study by Wang (2010) some authors have considered Saucrosmylidae as a distinct family, either closely related to Osmylidae ( Makarkin et al., 2013; Liu et al., 2014; Khramov, 2017), or closer to Myrmeleontoidea (i.e., psychopsid-clade) ( Yang et al., 2012), while others have continued to treat it as a subfamily of Osmylidae ( Liu et al., 2013) . Saucrosmylidae was finally elevated to family rank formally by Fang et al. (2015) and we follow this decision herein. Genera within Saucrosmylidae have distinctive variations in wing markings and wing shape, but tend to be homogeneous amongst genera, indicating a preponderance of genera based on species-level characteristics (e.g., nine species in eight genera). For example, while features such as shape of RP and posterior margin of the wing may be typically useful generic level characters in osmyloid genera, wing markings and rows of cells are usually not. Moreover, only the hind wing is known for Rudiomsylus and Daohugosmylus (see Fang et al., 2016), while the forewing is only known for Huiyingosmylus and likely Thaumatomerobius . As discussed in Winterton & Brooks (2002), the erection of numerous monotypic genera based on spurious species-level characters results in the continued proliferation of monotypic genera for any newly discovered taxa as the previously described genera are too narrowly defined. Similarly, the limits of the various genera of Saucrosmylidae require reevaluation in a phylogenetic context, for example, based on more stable features such as the shape of RP in both wings. The shape of RP in both wings suggests that there are two groups of taxa, including those with a relatively straight RP (i.e., Huiyingosmylus , Daohugosmylus , Rudiosmylus , Saucrosmylus , Ulrikezza ) and those with an RP that is arched anteriorly (i.e., Bellinympha , Laccosmylus and Thaumatomerobius ). Various keys to species are presented by Liu et al. (2013, 2014) and Fang et al. (2016). Larvae are unknown for this family.

Included genera. Bellinympha Wang et al. , Daohugosmylus Liu et al. , Huiyingosmylus Liu et al. , Laccosmylus Ren & Yin , Rudiosmylus Ren & Yin , Saucrosmylus Ren & Yin , Thaumatomerobius Ponomarenko , Ulrikezza Fang et al.