Megaraphidia hopkinsi, Archibald & Makarkin, 2021

Archibald, S. Bruce & Makarkin, Vladimir N., 2021, Early Eocene snakeflies (Raphidioptera) of western North America from the Okanagan Highlands and Green River Formation, Zootaxa 4951 (1), pp. 41-79 : 53-56

Megaraphidia hopkinsi sp. nov.

Figs 8 , 9

Raphidioptera : Greenwood et al., 2005: 180, Fig. 4 .

Type material. Holotype UWBM77544 , collected by Donald Hopkins in 1990; deposited in the UWBM collections. A nearly complete female specimen preserved in lateral aspect, except the head in ventral aspect.

Type locality and horizon. The One Mile Creek exposure of the Allenby Formation north of Princeton, British Columbia, Canada (part of the Okanagan Highlands series); early Eocene (Ypresian) .

Etymology. The specific epithet is a patronym formed from the surname of Don Hopkins, collector of the holotype.

Diagnosis. May be distinguished from other species of Megaraphidia by broad head [cuneate in M. ootsa ]; forewing costal space narrow (2 times wider than subcostal space) [2.3 in M. antiquissima , 2.6 in M. exhumata , 2.9 in M. klondika , 3.0 in M. elegans ]; subcostal veinlets more strongly inclined than in other species.

Description. Female. Body length (without ovipositor) approximately 11.3 mm. Head disarticulated, exposed ventrally, yellowish-brown; broad, not narrowed posteriorly except for posterior-most short portion; gula well discernible, narrow. Mouthparts very poorly preserved, incomplete. Prothorax broad in lateral view, relatively short, approximately 2 mm long (0.18 body length); mainly yellowish-brown. Meso-, metathorax, legs appear very dark, blackish; details poorly discernible. Abdominal tergites, sternites very dark, poorly preserved; 9th tergite narrow; ectoproct appears large; ovipositor incompletely preserved.

Forewing: 8.0 mm long as preserved (approximately 9.4 mm estimated length), 2.95 mm wide (estimated length/ width: 3.19). Costal space moderately broad, dilated at proximal 1/4 length; nine subcostal veinlets simple, distally widely spaced, proximally more closely spaced. ScP relatively long, terminating on costal margin slightly distad crossvein 2ra-rp. Subcostal space very broad, with basal crossvein located father to origin of RP than to divergence of M, CuA; distal crossvein (2scp-r, forming basal margin of pterostigma) straight. Only poorly preserved proximalmost part of pterostigma discernible. RA space with one preserved crossvein (2ra-rp) well proximad pterostigma. RP originating 0.46 estimated wing length, with two preserved proximal branches: RP1 deeply, dichotomously forked, with anterior branch simple, posterior branch shallowly forked (right wing); relatively shallowly forked once (left wing). RP2 incompletely preserved. One intraradial crossvein rp1-pr2 between stem of RP1, RP2. Three crossveins between RP, MA: 1r-m, 2r-m connecting stem of RP, MA; 3r-m connecting RP1, anterior branch of MA. M fused with CuA for very short distance; forked well proximad origin of RP. MA deeply, dichotomously forked twice. MP slightly zigzagged, anterior trace with two simple long branches. Two long intramedian crossveins form two doi; basal doi slightly shorter than distal. Anterior trace of CuA strongly zigzagged, fused with MP for short distance to form part of posterior margin of basal doi; one long simple branch. CuP simple distally. Crossvein icu between CuA, CuP long. AA1 simple; AA2+AA3 then AA2 strongly incurved, simple distally; AA3 not preserved.

Hind wing: 6.9 mm long as preserved (approximately 8.6 mm estimated length), 2.75 mm wide (estimated length/width: 3.12). Costal space relatively narrow (incompletely preserved); three preserved simple subcostal veinlets, widely spaced. ScP relatively long. One crossvein detected in subcostal space (2scp-r, forming basal margin of pterostigma), straight. Only proximal part of pterostigma, poorly preserved. Two crossveins between RA, RP preserved: 1ra-rp located slightly distad 2r-m; 2ra-rp located slightly distad termination of ScP. RP originating 0.32 estimated wing length, with two preserved pectinate branches. RP1 deeply dichotomously forked, with anterior branch simple, posterior branch shallowly forked; RP2 incompletely preserved. One intraradial crossvein rp1-rp2 between RP1, RP2. Two preserved crossveins between R, M: 1r-m very long, subparallel to R connecting to RP near its origin (its base not preserved); 2r-m connecting stems of RP, MA. M forked proximad origin of RP. MA deeply, dichotomously forked twice. MP: anterior trace slightly zigzagged, simple, with three simple pectinate branches, all long (right wing), two long, one short (left wing). Two intramedian crossveins forming two doi; basal doi markedly shorter than distal. Two crossveins between M and Cu: basal 1m-cu long, curved, somewhat oblique (with its ante- rior end inclined to wing base), connecting M, CuA; 2m-cu straight, with its anterior end inclined toward apex, connecting MP, CuA. Anterior trace of CuA simple distally, with one simple branch. One crossvein (icu) between CuA, CuP long. CuP fused with AA1+2, then AA1 for long distance. AA1 basally fused with AA2. AA3 not preserved.

Remarks. The broad head of this species is rather similar to that of e.g., species of Phaeostigma and Agulla arizonica ( Banks, 1911) , but its shape is not characteristic of most other Raphidiidae , in which the head is clearly narrowed posteriorly (cuneate) (e.g., Megaraphidia ootsa : Fig. 3A ). Some species of Raphidiidae (including A. arizonica ), however, show striking variation in head shape (see e.g., Carpenter, 1936: Fig. 5 ).

The variation of venation seen in the left and right wings of the holotype shows a remarkable example of fluctuating asymmetry (i.e., non-directional deviation from bilateral symmetry: Palmer & Strobeck, 1986). RP1 is forked only once in the right wing (1), but twice in the left; and the anterior branch of MP is forked once in the right wing, but twice in the left (2) (see Fig. 9 ). Condition (1) occurs very rarely in fossil Raphidiidae in North America (and this is its first record in the early Eocene), and condition (2) is not detected in any other of these specimens.

Figures

FIGURE 3. Megaraphidia ootsa sp. nov., holotype RBCM P1556, specimen as preserved. Scale bars = 5 mm.

FIGURE 4. Wing venation of Megaraphidia ootsa sp. nov., holotype RBCM P1556. A, right forewing, B, left forewing; C, right hind wing; D, left hind wing. Scale bar = 3 mm (all to scale).

FIGURE 5. Megaraphidia klondika sp. nov., holotype. A, counterpart UWBM 97073; B, part SR03-01-01; C, forewing venation; D, hind wing venation. Scale bar = 3 mm (all to scale).

FIGURE 8. Megaraphidia hopkinsi sp. nov., holotype UWBM77544. A, specimen as preserved; B, head. gu, gula. Scale bars = 5 mm (A), 1 mm (B).

FIGURE 9. Wing venation of Megaraphidia hopkinsi sp. nov., holotype UWBM77544. A, right forewing; B, left hind wing; C, right forewing; D, left hind wing. Scale bar = 3 mm (all to scale).