Megaraphidia klondika, 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 : 49-52

Megaraphidia klondika sp. nov.

Figs 5– 7 , 10E, F

Type material. Holotype SR 03-01-01 (part), UWBM 97073 (counterpart), collected by Wes Wehr, 13.v.2003, deposited in the SR collections (SR 03-01-01) and UWBM collections ( UWBM 97073 ). An overlapping forewing and hind wing, both almost complete, slightly damaged.

Other material. SR 16-004-001.01 (only part), collected by Joanne West, 13.vi.1998, locality the same as holotype, deposited in the SR collections. An apical well-preserved portion of a wing.

SRUI 99-71-63 (part and counterpart), 28.iv.2017, collected by Gregg Wilson at the same exposure, 28.iv.2017, deposited in the SR collections. A well-preserved middle portion of a hind wing.

Type locality and horizon. Tom Thumb Tuff Member of the Klondike Mountain Formation , exposure A0307, Republic, Washington, U.S.A.; early Eocene (Ypresian) .

Etymology. The specific epithet is an adjective referring to the Klondike Mountain Formation shale within which its specimens are preserved.

Diagnosis. May be distinguished from other species of Megaraphidia by branch of RA within pterostigma very poorly or not visible [clearly visible in M. elegans , M. exhumata ]; costal space strongly dilated in forewing (2.9 times wider than subcostal space) [2.3 in M. antiquissima , 2.0 in M. hopkinsi , M. ootsa ]; two doi approximately equal in length in hind wing [proximal doi shorter than distal in M. antiquissima , M. ootsa , M. hopkinsi ]; two pectinate branches of CuP in hind wing [one in M. hopkinsi , M. antiquissima ].

Description. Holotype. Forewing 12.4 mm long, approximately 3.9 mm wide (length/width: 3.2). Costal space broad, strongly dilated at proximal 1/4 length; eight preserved subcostal veinlets simple (probably nine to ten total), three basal veinlets more closely spaced. ScP relatively long, terminating on costal margin slightly distad crossvein 2ra-rp; length from termination of ScP to pterostigma approximately equal to length of pterostigma. Subcostal space broad, with basal crossvein located in middle between origin of RP, divergence of M, CuA; distal crossvein (2scp-r, forming basal margin of pterostigma) slightly incurved. Pterostigma relatively short, strongly pigmented. Two RA branches (none detected within pterostigma); one forming distal margin of pterostigma; other distad pterostigma; none forked. RA joining margin well before apex. RA space with two crossveins forming two radial cells: 2ra-rp located well proximad pterostigma, slightly proximad termination of ScP; 3ra-rp located in middle of pterostigma along RA. RP originates at nearly half (0.44) wing length, with five pectinate branches: RP1 deeply dichotomously forked twice; other branches forked once. One long intraradial crossvein rp1-rp2 between stem of RP, RP1. Three crossveins between RP, MA: 1r-m, 2r-m connecting stem of RP, MA; 3r-m connecting RP1, anterior branch of MA. M close to R (appears fused) for considerable distance, and then fused with CuA for short distance; forked well proximad origin of RP. MA deeply dichotomously forked twice. MP zigzagged, anterior trace with three simple branches (proximal-most branch fused basally for long distance with CuA). Two intramedian crossveins form two doi, approximately equal in length. Cu basally not visible; dividing to CuA, CuP relatively close to wing base.Anterior trace CuA strongly zigzagged, fused with MP for long distance to form part of posterior margin of basal doi, and then with proximal-most branch of MP; two pectinate long simple branches, their bases close). CuP simple, aligned with Cu. Crossvein icu between CuA, CuP long. AA1 with shallow fork near margin; AA2, AA3 simple. One short crossvein iaa in anal space, between AA1, AA2.

Hind wing 11.6 mm long, approximately 3.5 mm wide (length/width: 3.3). Costal space relatively broad (incompletely preserved); four preserved simple subcostal veinlets, widely spaced. ScP relatively long; length from termination of ScP to pterostigma slightly shorter than length of pterostigma. One crossvein detected in subcostal space (2scp-r, forming basal margin of pterostigma), slightly incurved. Pterostigma elongate, slightly longer than in forewing. RA with two branches (one presumably within pterostigma not detected); branch forming distal margin of pterostigma slightly curved; one simple branch distad pterostigma; portion of RA distad pterostigma relatively short. Three crossveins between RA, RP: 1ra-rp located slightly distad 2r-m; 2ra-rp located clearly proximad termination of ScP; 3ra-rp terminating within pterostigma, just proximad its middle along RA. RP originating 0.39 wing length, with five pectinate branches, two proximad 3ra-rp, three distad. RP1 deeply dichotomously forked twice; other branches rather deeply forked once each. One intraradial crossvein rp1-rp2 between RP1, RP2. Three crossveins between R, M: 1r-m very long, subparallel to R connecting to RP near its origin (its base unclear); 2r-m connecting stems of RP, MA; 3r-m connecting RP1, anterior branch of MA. M forked proximad origin of RP. MA deeply dichotomously forked twice. MP: anterior trace zigzagged, simple, with three simple, pectinate branches. Two intramedian crossveins forming two doi, approximately equal in length. Two crossveins between M and Cu: basal 1m-cu long, very oblique, connecting M, CuA; 2m-cu straight, perpendicular to MP, connecting it, CuA.Anterior trace of CuA probably simple distally, with two simple branches (incompletely preserved). One crossvein (icu) between CuA, CuP long. CuP originating very closely to wing base; fused with AA1+2, then AA1 for long distance. AA1 basally fused with AA2 for long distance. AA3 simple. Jugal vein stout.

SRUI99-71-63 ( Fig. 6 ). Hind wing 7.7 mm long as preserved (11 mm estimated length), 3.5 mm wide as preserved (approximately identical to estimated width). Costal space relatively broad (incompletely preserved); five preserved subcostal veinlets (three distal-most simple), widely spaced. Subcostal space narrow proximally, broadened distally; no crossveins, pterostigma preserved. Distal part of RA not preserved. Two crossveins between RA, RP preserved: 1ra-rp located slightly distad 2r-m; 2ra-rp located clearly proximad termination of ScP. RP originates far from wing base, with only RP1 partially preserved. One intraradial crossvein (rp1-rp2) detected, between RP1, RP2 near its origin. Three crossveins between R, M: 1r-m very long, subparallel to R connecting to RP near its origin (its base unclear); 2r-m connecting stems of RP, MA; 3r-m connecting RP1, anterior branch of MA. M forked proximad origin of RP. MA deeply dichotomously forked twice. MP: anterior trace zigzagged, simple, with three simple, pectinate branches. Two intramedian crossveins forming two doi, approximately equal in length. Two crossveins between M and Cu: basal 1m-cu long, very oblique, connecting M, CuA; 2m-cu straight, connecting it, CuA. Anterior trace of CuA simple distally, with two probably simple branches (incompletely preserved). Small distal portions of CuP, AA1 preserved.

SR 16-004-001-01.01 ( Fig. 7 , 10F ). Distal part of wing preserved, 5.7 mm long, 3.4 mm wide. Pterostigma elongate, 1.72 mm long (along costal margin), 0.47 mm wide (length/width: 3.66). RA with three branches: one within pterostigma indistinct; branch forming distal margin of pterostigma slightly curved; one simple branch distad pterostigma. Portion of RA distad pterostigma relatively short (along costal margin), 0.63 length of pterostigma. Two crossveins between RA, RP preserved; 3ra-rp located in distal part of pterostigma. RP with five pectinate branches, two proximad 3ra-rp, three distad. RP1 rather deeply forked; its anterior branch simple, posterior forked. Other branches forked once each. One intraradial crossvein rp1-rp2 between origin of RP1, RP2. Two crossveins between R, M detected: 2r-m connecting stems of RP, probably MA; 3r-m connecting RP1, anterior branch of MA. MA deeply dichotomously forked twice.

Remarks. The preserved hind wing venation of SRUI-99-71-63 is almost identical to that of the hind wing of the holotype.

It is not determinable if specimen SR 16-004-001.01, the distal part of a wing, is a forewing or hind wing. Its venation differs from that of the holotype by its slightly more distal position of crossvein 3ra-rp, more distal forking of RP1, the anterior branch of RP1 being simple, and as a branch of RA within the pterostigma is visible, although indistinct ( Fig. 10F ). We preliminary consider these differences as intraspecific variability.

Figures

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 6. Megaraphidia klondika sp. nov., specimen SRUI99-71-63. A, part; B, counterpart; C, drawing of the hind wing venation. Scale bar = 3 mm (all to scale).

FIGURE 7. Megaraphidia klondika sp. nov., specimen SR16-004-001-01.01. A, specimen as preserved; B, drawing. Scale bar = 3 mm (both to scale).

FIGURE 10. Pterostigmata of Megaraphidia. A, M. antiquissima sp. nov., right wings of the holotype RBCM P1555; B, M. antiquissima sp. nov., left wings of same specimen; C, M. ootsa sp. nov., right hind wing of the holotype RBCM P1556; D, M. ootsa sp. nov., left wings of same specimen; E, M. klondika sp. nov., holotype, an overlapping forewing and hind wing SR03-01-01; F, M. klondika sp. nov., specimen SR-16-004-001-1. RAf, RA of forewing; Rah, RA of hind wing. Scale bars = 0.5 mm.