Lithocorydalus, Jepson, James E. & Heads, Sam W., 2016

Jepson, James E. & Heads, Sam W., 2016, Fossil Megaloptera (Insecta: Neuropterida) from the Lower Cretaceous Crato Formation of Brazil, Zootaxa 4098 (1), pp. 134-144 : 139

Genus: Lithocorydalus gen. nov.

Etymology. From lithos, Greek for stone and Corydalus an extant genus of megalopteran.

Type species: Lithocorydalus fuscata gen. et sp. nov.

Diagnosis. Lithocorydalus gen. nov. differs from the other genera of Corydalidae by a combination of the following characters: Elongate forewing: length 17.9 mm. Very dark wing colouration. Venation relatively simple: Rs branches majority simple, MA simple, MP deeply forked: MP1, MP2 simple. Elongate hind wing, free branch of MA in hind wing, forming long cell between it and R. Two nygmata present, tibial spur absent.

Comparison. The absence of a bilobed 4th tarsomere in Lithocorydalus gen. nov. separates it from taxa in Sialidae and Corydasialidae . Lithocorydalus gen. nov. can be separated from Parasialidae and further separated from Sialidae by its general wing venation. Lithocorydalus gen. nov. has a relatively small to medium sized forewing, which is larger than Cretochaulus (10 mm), but smaller than the other taxa: Cratocorydalopsis gen. nov (25 mm), Eochauliodes (30 mm), and Jurachauliodes (35 mm). The uniform, very dark colour pattern differs from all other genera: Cratocorydalopsis gen. nov.: (dark base and apex, pale centre), Eochauliodes (hyaline with dark stripes), Jurachauliodes (hyaline with some dark patches). The venation is relatively simple in Lithocorydalus gen. nov. compared to the other genera, with regards to Rs, Cratocorydalopsis gen. nov differs by having more branches of Rs; in Cretochaulus and Eochauliodes, Rs is dichotomously forked, and in Jurachauliodes Rs has three branches that are all forked in forewing, but in the hind wing, all but one is forked. The structure of MA is similar to Cretochaulus, which is also simple; in all other genera it is forked. The deeply forked MP is shared with all genera, but the simple MP1 and MP2 differs from Cretochaulus, Eochauliodes and Cratocorydalopsis gen. nov., which have MP1 forked and MP2 simple, Jurachauliodes has MP1 forked twice (forewing), dichotomously forked (hind wing), MP2 simple (forewing), and forked (hind wing). The elongate hind wing is observed in Eochauliodes, but broad in all other genera. The free branch of MA is similar to the other genera, except Eochauliodes, which is absent (possibly due to preservation). The presence of two nygmata is the same in the other fossil genera except Jurachauliodes and Cratocorydalopsis gen. nov.: in which it is absent, however this may be due to preservation. The absence of a tibial spur is also observed in Cratocorydalopsis gen. nov.; in Cretochaulus it is unknown, but in Eochauliodes and Jurachauliodes it is present.