Dysagrion pruettae Archibald & Cannings, 2021

Archibald, Bruce, Cannings, Robert A., Erickson, Robert J., Bybee, Seth M. & Mathewes, Rolf W., 2021, The Cephalozygoptera, a new, extinct suborder of Odonata with new taxa from the early Eocene Okanagan Highlands, western North America, Zootaxa 4934 (1), pp. 1-133 : 37-41

Dysagrion pruettae Archibald & Cannings , new species

Figs. 16–18 .

Diagnosis. Wings most easily distinguished from those of other Dysagrion species by pterostigma 6–7 times longer than wide [ D. packardii : 4 times; D. fredericii : 5; D. lakesii , 5]; by maximum width 7.4 mm (forewings), 7.0 mm (hind wings) [ D. packardii : 8.7 mm; D. lakesii : 8.4 mm; D. fredericii : about 9.0 mm]; maximum width 24–25% length arculus to apex, (fore-, hind wings) [ D. fredericii : 30%; D. packardii : 27%; D. lakesii 28%]. Further from D. packardi by anterior of quadrangle longer than base [ D. packardi : about equal]; from D. fredericii by no accessory antenodal crossveins [ D. fredericii : one (see above)].

Type material. Holotype: SR 13-005-012 A, B, collected at Republic B 4131 by Katrina Pruett, 24.vi.2013: a specimen preserved in lateral aspect, missing much of the head and the abdomen distal to segment 3 with portions of the legs present; all wings present, overlapping. Housed in the Stonerose Interpretive Center collection.

Description. Holotype, SR 13-005-012A, B, female. Head missing. Prothorax more or less oval in lateral aspect, 1.3 mm long, with leg attached; pterothorax in lateral aspect, about 8.2 mm long, mostly dark coloured with narrow pale stripes on mesopleural (humeral) suture and (probably) metapleural suture. Preservation of metepimeron unclear. Best preserved leg is the mesothoracic or metathoracic one, probably the latter; rather short, femur only 5.7 mm long, about as long as the tibia and abdominal segment 3; spines on femur and tibia short, weak and irregulary spaced.

Wings: forewing 1 (blue in Figs. 16B , 18A ): petiolate; 35.0 mm long, about 21.7 mm nodus to apex; 7.4 mm wide; hyaline throughout. Nodus at 37% wing length. Pterostigma long, approximately seven times as long as wide, subtending unknown number of cells (preservation); oblique proximal margin, strikingly more oblique distal margin; with oblique brace vein. Few crossveins preserved in postnodal, postsubnodal spaces, not aligned. One cell wide distal to pterostigma in costal space. RA meets margin slightly anterior to apex. RA–RP1, RP1–IR1 spaces one cell wide to margin. Linear supplementary sectors in IR1–RP2 space (2), RP2–IR2 space (2), IR2–RP3-4 space (4), RP3-4–MA space (4–5) as in Fig. 18A (small blue arrows). Possible area of crossvein O not preserved. IR1 origin unclear; origins of supplementary sectors in IR1–RP2 space unclear. RP2 origin not definable relative to IR2 by preservation; IR2; origin unclear. RP3-4: origin unclear. MA zigzags distal to level of origin of RP2, linear again near wing margin. MP linear, with light curves from quadrangle to terminus; MP–CuA space widens near terminus. CuA becomes zigzagged around presumed level of origin of RP3-4, increasingly so to terminus. CuA–A space five cells wide at widest proximal to level of origin of RP2.

Forewing 2 (red in Figs. 16B , 17A ): as for forewing 1 except pterostigma six times as long as wide; subtends unknown number of cells (preservation); oblique brace vein present. All crossveins preserved in postnodal space, 18; 15 in postsubnodal space, but apparently not all, these not aligned. IR1 origin five cells distal to origin of RP2; IR1–RP2 space become two cells wide six cells distal to origin. RP2 origin about three cells distal to subnodus. No crossvein O. IR2 origin not preserved. RP3-4: origin in middle third between arculus and nodus. CuA–A space maximum width unclear (posterior margin missing in this region), probably maximum four cells wide.

Hind wing 1 (orange in Figs. 16B , 18B ): small anterior portions discernable. Petiolate, 33 mm long, 21.4 mm nodus to apex; hyaline throughout. Nodus at 36% of wing length. Pterostigma width not accurately measurable (RA bent); oblique proximal margin, more oblique distal margin; oblique brace vein present; apparently two cells subtend pterostigma (?). Crossveins in postnodal, postsubnodal spaces incompletely preserved, not aligned. Costal space one cell wide distal to pterostigma. RA meets margin slightly anterior to apex. RA–RP1 space one cell wide to margin; RP1–IR1 space one cell wide but two right at margin. Undetermined number of supplementary sectors in IR1–RP2 space.

Hind wing 2 (green in Figs. 16B , 17B ): more complete than hind wing 1. As for hind wing 1, except: 7.0 mm wide; length of pterostigma approximately seven times width; oblique brace vein present. Few crossveins preserved in postnodal space, 12 in postsubnodal space, not complete; these not aligned. Linear supplementary sectors in IR1–RP2 space (2), RP2–IR2 space (2), IR2–RP3-4 space (4), RP3-4–MA space (4). IR1 origin five cells distal to that of RP2; becomes two cells wide seven cells distal to origin. RP2 origin three cells distal to origin of IR1. IR2 origin very close to subnodus. RP3-4: origin in middle third between arculus and nodus. No crossvein O. MA zigzags increasingly beyond level of nodus, linear again near margin. MP linear, evenly curved from quadrangle to terminus. CuA increasingly zigzagged from level of nodus; CuA–A space maximum four cells wide.

Abdomen: dark coloured dorsally, pale ventrally; segments 1 to 2 preserved in lateral aspect, segment 3 in ventral aspect; thickness of abdomen and lack of secondary genitalia on venter of segment 2 indicate a female specimen.

Etymology. The specific epithet is a patronymic formed from the surname of Katrina Pruett, the collector of the holotype, recognising her contribution.

Range and age. Republic locality B4131 of the Tom Thumb Tuff Member of the Klondike Mountain Formation; latest Ypresian.

Discussion. If the Green River specimens are hind wings, they are notably longer: D. pruettae arculus to apex: 28.4 mm, D. packardii : 31.7 mm, D. lakesii : 30.0 mm, D. fredericii : about 30.5 mm. If they are forewings, their lengths match those of D. pruettae more closely, 30.7 mm long arculus to apex.

Figures

FIGURE 16. Dysagrion pruettae, new species holotype, SR 13-005-012. A, photograph; B, drawing. Wings and labels (FW, forewing; HW, hind wing) colour-coded to match Figs. 17 and 18. Both to scale, 5 mm.

FIGURE 17. Dysagrion pruettae holotype, SR 13-005-012.A, drawing of forewing (FW); B, drawing of hind wing (HW). FW, HW label colours refer to those in Fig. 16. Both to scale, 5 mm.

FIGURE 18. Dysagrion pruettae holotype, SR 13-005-012.A, drawing of forewing (FW); B, drawing of hind wing (HW). FW, HW label colours refer to those in Fig. 16. Small, blue arrows indicate supplementary sectors. Both to scale, 5 mm.