Fossil Megaloptera (Insecta: Neuropterida) from the Lower Cretaceous Crato Formation of Brazil
Jepson, James E.
Heads, Sam W.
Zootaxa
2016
4098
1
134
144
[249,436,838,864]
Insecta
Sialidae
Lithocorydalus
Animalia
Megaloptera
5
139
Arthropoda
genus
gen. nov.
Etymology.From lithos,Greek for stone and Corydalusan extant genus of megalopteran.
Typespecies: Lithocorydalus fuscata gen. et sp. nov.
Diagnosis. Lithocorydalus gen. nov.differs from the other genera of Corydalidaeby 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 Sialidaeand Corydasialidae. Lithocorydalus gen. nov.can be separated from Parasialidaeand further separated from Sialidaeby 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. novdiffers by having more branches of Rs; in Cretochaulusand Eochauliodes, Rs is dichotomously forked, and in JurachauliodesRs 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, Eochauliodesand Cratocorydalopsis gen. nov., which have MP1 forked and MP2 simple, Jurachauliodeshas 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 Jurachauliodesand 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 Cretochaulusit is unknown, but in Eochauliodesand Jurachauliodesit is present.