Fang et al.—Late Triassic elcanid insect fossil from North America 92(6):1028–1034 1


1031


2 CuA


ScA MA RP


ScP


RA


CuPa2 CuA+CuPa1 MP


MA2


MA1


Figure 2. Light photomicrograph (1) and interpretive drawing (2) of the holotype, 06/L4BH/2-1/107, VPIGM-4698. Interpretive drawing combines observation of the part and counterpart. Scale bar=1mm. Abbreviations of forewing venation: ScA and ScP, anterior and posterior sub-costa vein, respectively; RA, anterior radial vein; MA, anterior media veins; MA1 and MA2, first and second branch of anterior media vein, respectively; CuA, anterior cubitus veins; CuPa, anterior branch of cubitus vein; CuPa1, first branch of CuPa; CuPa2, posterior branch of CuPa; CuA+ CuPa1, fused part of anterior cubitus vein and first branch of CuPa; RP, posterior radial vein; MP, posterior media vein.


Color occurrence between RA and anterior margin (ptero- stigma-like area), also along crossveins between branches of RP (and RP+MA1). The pterostigma-like area ~4.0mm long, and covered with seven branches of RA.


Etymology.—The species name is after the state of Virginia.


Remarks.—The holotype was previously figured by Muscente and Xiao (2015, fig. 6A, B). An additional specimen with unclear forewings was reported in Liutkus et al. (2010, fig. 3D). The latter specimen probably belongs to the same species, but the poor preservation of the basal part of its forewings prevented adefinitive assignment to this species.


Discussion


Preservation of the wing.—Results of combined SEM and EDS are consistent with previous studies showing that, like other fossils from the Solite Quarry Lagerstätte, the specimen is pre- served as carbonaceous compressions with minimal topographic relief (Kearns and Orr, 2009; Muscente and Xiao, 2015).


In general, the specimen was divided evenly between its part and counterpart during rock splitting (Fig. 3.1, 3.2). The Z-contrast in BSE SSD images of the part and counterpart indicates that the fossil is predominantly comprised of a lower Z material than the silicate minerals constituting the underlying shale; EDS elemental mapping confirms that this low Z material contains relatively higher concentrations of carbon than the shale, and thus is consistent with the presence of organic matter (Fig. 3.4–3.7). In some BSE SSD images, this carbonaceous material is encrusted by a material with a high Z relative to the carbonaceous material and shale (Fig. 3.3; see also Muscente and Xiao, 2015, fig. 6L–P). This relatively high Z material most likely consists of silicate minerals (e.g., biotite), which report- edly encrust organic matter of fossils in the Solite Quarry (Kearns and Orr, 2009; Muscente and Xiao, 2015). The high Z material is not readily apparent in EDS elemental maps, suggesting that the silicate minerals are too thin for detection with EDS (Fig. 3.7–3.11). Beam-energy BSE SSD Z-contrast image series of the


specimen (Fig. 3) indicates that the various veins and structures in the wing are preserved as carbonaceous films of different


Figure 3. SEM images and EDS elemental maps of the forewing of C. virginiana n. gen. n. sp., holotype (06/L4BH/2-1/107, VPIGM-4698). (1) Composite SE ETD image (VA=10 keV) of counterpart; (2) composite SE ETD image (VA=10 keV) of part; (3) composite BSE SSD Z-contrast image (VA=3 keV) of area denoted by solid black line in (2); arrow in (3) indicates relatively high-Z material encrusting carbonaceous material (most likely silicate materials such as biotite); (4–7) EDS elemental maps of pterostigma-like structure in area denoted by solid white line in (1); (8–11) beam-energy BSE SSD Z-contrast image series of area denoted by dashed black line in (2); (12–15) illustrative diagrams of (8–11). Scale bars=1mm.


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