Lithochrysa ferruginea (Cockerell, 1909)

Makarkin, Vladimir N., Antell, Gwen S. & Archibald, S. Bruce, 2022, A revision of Chrysopidae (Neuroptera) from the late Eocene Florissant Formation Colorado, with description of new species, Zootaxa 5133 (3), pp. 301-345 : 325-328

Lithochrysa ferruginea (Cockerell, 1909) , stat. res.

Figs 17–19

Palaeochrysa ferruginea Cockerell, 1909b: 218 , 219, Fig. 6 ; Cockerell 1914: 717; Carpenter 1935: 266, 267 (as a synonym of Lithochrysa concinnula ); Martins-Neto & Vulcano 1989: 189, 190 (as a synonym of Palaeochrysa concinnula ); Archibald & Makarkin 2017: 397, 399, 400.

Paleochrysa [sic] ferruginea: Rodeck 1938: 290 ; Adams 1967: 231 (as a synonym of Palaeochrysa concinnula ).

Type material. Holotype UCM 18625, deposited in UCM, collected by S.A. Rohwer; a nearly complete specimen in lateral aspect, covered with Canada balsam.

Other examined material. FLFO 9745 (only part), collected by Julius Torres in 2013; a relatively well-preserved nearly complete specimen with all four wings overlapped.

Type locality and horizon. USA: Colorado: Teller County, Florissant: Station 13B ( Cockerell 1907b) [holotype]; Lower Shale unit of Evanoff et al. 2001 (precise collecting locality unknown) [specimen FLFO 9745]; Eocene, late Priabonian; Florissant Formation.

Diagnosis. May be distinguished from other species of the genus by more distal 1r-m (clearly distad 2m-cu) [ L. concinnula , L. wickhami , L. meyeri sp. nov.: ca. at level of 2m-cu]; 9–10 branches of RP [ L. meyeri sp. nov.: 12 branches]; cells between branches of CuA distinctly longer than wide [ L. wickhami : cells between these only slightly longer than wide]; hind wing RP1 distad first crossvein ra-rp [ L. concinnula : proximad].

Redescription. Holotype ( Fig. 17 ). Body, legs poorly preserved. Palpi partially preserved, but details not discernible. Eyes ca. 0.5 mm in diameter. Most part of antennae preserved; scapus large, slightly elongated.

Forewing ca. 11.5 mm long, 3.9 wide (length to width ratio ca. 2.95). Costal space relatively narrow. Subcostal veinlets simple proximad pterostigmal region, widely spaced. Pterostigma indistinct. Distal part of Sc not discernible. Subcostal space broad; subcostal crossveins not preserved. RA long. RA space broad, with 10 preserved crossveins (apparently 11 when complete). RP originating relatively far from wing base (at ca. 0.28 of complete length). Anterior trace of RP somewhat zigzagged, with nine branches. Basal crossvein between RP, M (1r-m) rather long, connecting anterior trace of RP, MA within im at nearly half its length. M not fused with R basally; sigmoid before its fork; dividing to MA, MP at nearly level of origin of RP. MA forked distad Psc; deeply forked at Psc. Crossvein between MA, MP (1im) rather long. Im elongate, slightly divergent distally (length/width ratio 2.35). Psm poorly developed, zigzagged. Crossvein 2m-cu very long, connecting im, CuA at nearly proximal one-fourths of im. CuA probably with three simple branches. Psc rather well developed, slightly zigzagged. CuP deeply forked. 2icu connecting CuA, anterior branch of CuP proximad 2m-cu. CuA, A1 closely approaching for long distance. A1, A2 arched, simple. Crossvein between A2, A3 very long. Two gradate series of crossveins, nearly parallel: inner series with six preserved crossveins distad MA (apparently 8–9 complete); outer series with seven crossveins distad RP2.

Hind wing ca. 10 mm long, ca. 3.5 mm wide. Costal, subcostal spaces poorly preserved; subcostal veinlets, subcostal crossveins not discernible. Pterostigma indistinct. RA fragmentarily preserved. RA space broad, with seven preserved crossveins. Anterior trace of RP zigzagged, with nine branches, of these three distal-most simple. Psm poorly discernible. MA fragmentarily preserved, deeply forked at Psc. MP nearly straight, deeply forked at Psc. Proximal crossvein between MA, MP (1im) long. CuA fused with MP for long distance; with one simple branch before fusion. CuP fragmentarily preserved. Anal veins not discernible. Psc probably well developed (poorly preserved). Two gradate series of crossveins, poorly preserved.

Specimen FLFO 9745 ( Figs 18 , 19 ). Head: face, genae long; fourth, fifth segments of maxillary palpi long ( Fig. 18B ); eyes 0.4 mm in diameter; antennae rather well preserved, but details not discernible. Thorax (lateral view) poorly preserved. Legs covered with dense, short setae. Abdomen very poorly preserved, apical portion missing.

Forewing 10.8 mm long, 3.5 wide (length to width ratio 3.09). Costal space relatively narrow; strongly narrowed towards pterostigmal region. Subcostal veinlets simple proximad pterostigmal region, rather widely spaced. Pterostigma indistinct. Distal part of Sc not discernible. Subcostal space moderately narrow; subcostal crossveins not discernible. RA long, ending on margin near wing apex. RA space broad, with 11 crossveins (left wing). Origin of RP relatively far from wing base (at ca. 0.26 of complete length). Anterior trace of RP zigzagged, apically not forked, with 10 branches; all forked except two (left wing) or three (right wing) distal-most. Basal crossvein between RP, M (1r-m) rather short, connecting anterior trace of RP, MA within im at proximal third im length. M not fused with R basally; sigmoid before fork; dividing to MA, MP at level of origin of RP. MA, MP each deeply forked at Psc. Crossvein between MA, MP (1im) rather long. Im elongate (length/width ratio 3.00–3.07); MA, MP within im not divergent distally. Psm very poorly developed. Crossvein 1m-cu short; 2m-cu rather long, connecting im, CuA at nearly proximal one-sixth (left wing) or one-ninth (right wing) of im. CuA probably with three simple branches. Psc rather well developed, slightly zigzagged. CuP deeply forked. 2icu connecting CuA, anterior branch of CuP proximad 2m-cu. A1, A2 arched, simple. Two gradate series of crossveins, nearly parallel; inner series slightly sigmoid, with nine crossveins distad MA; outer series nearly smooth, with eight crossveins distad RP2.

Hind wing ca. 9.9 mm long, ca. 3.3 mm wide. Costal, subcostal spaces, Sc poorly discernible. RA long, ending on margin at wing apex. RA space rather broad, with ten (right wing) or nine (left wing) crossveins. Anterior trace of RP zigzagged, apically not forked, with nine branches, all forked except two distal-most. M dividing to MA, MP probably at level of origin of RP (poorly preserved). MA basally crossvein-like, then fused with RP for long distance, then deeply forked at Psc. Psm poorly developed, zigzagged. MP nearly straight proximally; deeply forked at Psc. Crossvein 1im long. Additional crossvein m-cu present in right wing. CuA fused with MP for long distance, with two simple branches, one before fusion, other after. CuP, A1, A2 distally discernible, all probably simple. Psc rather well preserved. Two gradate series of crossveins: inner series with eight (right wing) or nine (left wing) crossveins distad MA; outer series with seven (left wing) or eight (right wing) crossveins distad RP1.

Remarks. The venation of the holotype and specimen FLFO 9745 agrees with the diagnosis of the species and is otherwise very similar, e.g., CuA in their hind wings each have one branch proximad its fusion with MP, a rare condition in the subfamily and unique among known Florissant Chrysopidae . We are confident that they are conspecific, differing only in small details.

Figures

FIGURE 6. Wing venation drawings of Archaeochrysa sp., specimen NHM.I.26921. A, right forewing; B, right hind wing; C, left forewing. Veins that cannot be assigned to the right fore- or hind wings are shown by dotted lines. Scale bars = 3 mm (all to scale).

FIGURE 17. Lithochrysa ferruginea (Cockerell, 1909), holotype UCM 18625. A, specimen as preserved; B, drawing of left forewing; C, drawing of left hind wing. Scale bars = 3 mm (B, C to scale).

FIGURE 18. Lithochrysa ferruginea (Cockerell, 1909). A, specimen FLFO 9745. A, specimen as preserved; B, head. e, eye; g, genae; mp, maxillary palpus. Scale bars = 3 mm (A), 1 mm (B).

FIGURE 19. Wing venation of Lithochrysa ferruginea (Cockerell, 1909), specimen FLFO 9745. A, left forewings; B, right forewing; C, right hind wings; D, left hind wing. Scale bar = 3 mm (all to scale).