Okanagrion liquetoalatum 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 : 70

Okanagrion liquetoalatum Archibald & Cannings , new species

Fig. 38 .

Diagnosis. Wings separated from those of O. hobani , O. threadgillae , O. worleyae , O. dorrellae , O. beardi by shape: length (arculus to apex) / maximum width 2.6 [ O. hobani : 3.2; O. threadgillae : 3.0, 3.1; O. worleyae holotype: 2.8, paratype: 3.1; O. dorrellae : 3.7; O. beardi : 3.3, 3.4]; from O. angustum by shape [ O. lochmum , O. worleyae , O. angustum apical region not preserved, but O. angustum distinctly narrower, see width, angle of posterior to anterior margin preserved between levels of nodus, origin of RP2]; from O. beardi , O. dorrellae by MP, CuA sub-parallel at terminus on posterior margin [ O. beardi : distinctly wider, O. dorrellae : widening, but less distinctly as CuA zigzagged distally ( O. angustum , not known); from O. lochmum by cells less dense apically: RA–RP1 space two cells wide distal to 1–2 cells proximal to pterostigma [ O. lochmum from 7–8 cells proximal to pterostigma], RA–RP1 space three cells wide distal from apical corner of pterostigma or one cell distal from that [ O. lochmum from about one cell proximal to pterostigma], RA–RP1 space becomes five cells wide over half distance from pterostigma to margin [ O. lochmum : from distal end of pterostigma]; from O. hobani by main veins less deeply curved near margin; from O. dorrellae by MP linear to terminus [ O. dorrellae : zigzagged distally]; from O. angustum , O. beardi by IR2 origin between RP1-2, RP3-4 [ O. angustum , O. beardi : origin on RP1-2].

Further separated by colouration (sex unknown): O. liquetoalatum : hyaline throughout; others with distinct colour patterning as in their diagnoses; O. worleyae : lightly infuscate throughout known wing.

Type material. Holotype: SR 06-69-17 A, B ( Fig. 38 ), collected at Republic B 4131 by Gregg Wilson, 29.iv.2006: a well preserved disarticulated wing, housed in the Stonerose Interpretive Center collections.

Description. Holotype, SR 06-69-17A, B, wing. Shape: oval distal to nodus, anterior margin rather straight between nodus, pterostigma, posterior margin evenly curved apical to petiole. Hyaline throughout. Length 30.5 mm, arculus to apex: 25.2 mm, nodus to apex: 20.3 mm, origin of RP2 to apex: 16.6 mm, arculus to base of pterostigma: 20.4 mm, nodus to base of pterostigma: 15.4 mm, nodus at 29% wing length; maximum width 8.5 mm. Pterostigma 3.5 longer than wide, subtends 5.5 cells, no oblique brace vein. Costal space distal to pterostigma maximum 3 cells wide; RA terminates at apex, slightly upturned at margin. 31 crossveins in postnodal space, none hyperstigmal, those in postsubnodal spaces not aligned. Maximum three cells wide distal to pterostigma in costal space. RA–RP1 space hardly narrows near margin. RP1–IR1 space goes to two cells wide eight cells distal to origin of IR1. IR1: origin eight cells distal to origin of RP2, zigzagged proximally. IR1 two cells wide six (or ten?) cells distal to origin. RP2: origin 5.5 cells distal to that of IR2. IR2: origin very close proximal to subnodus. RP3-4 origin near, distal to middle between arculus, nodus. Arculus at Ax2. No crossvein O. All main veins except base of IR1 linear. CuA–A space with five cells wide at widest.

Etymology. The specific epithet liquetoalatum is formed from the Latin liquet for clear and alatus (-a, -um) meaning winged.

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

Discussion. Wing falsely appears mottled in Fig. 38 photo by wetting with ethanol.

Figures

FIGURE 38. Okanagrion liquetoalatum holotype, SR 06-69-17. A, photograph; B, drawing. Both to scale, 5 mm.