Okanagrion angustum 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 : 66-68

Okanagrion angustum Archibald & Cannings , new species

Fig. 36 .

Diagnosis. Wings separated from those of all others but O. beardi by IR2 origin on RP1-2 [all others: origin between RP1-2, RP3-4]; from O. beard , O. dorrellae by Ax1 to nodus 1–1.5 mm longer than for O. beardi : 1.5 mm longer than for O. dorrellae ; from O. worleyae , O. dorrellae by narrower at level of nodus: O. angustum about 5.5 mm wide [ O. worleyae : about 4.5 mm, O. dorrellae 4 mm].

Further separated by colouration (sex unknown): similar to that of O. hobani in preserved portions (much of posterior margin, apical portion not preserved), differs from others as in its diagnosis.

Type material. Holotype: RBCM.EH2017.050.11.2491 ( Fig. 36 ), collected at McAbee by John Leahy, date unknown. Much of the proximal three-quarters of a wing. Housed in the Royal British Columbia Museum collections.

Description. Holotype, RBCM.EH2017.050.11.2491, wing. Shape: wing narrow, as in diagnosis; colour (preserved portion) as in O. hobani , see diagnosis; few crossveins in postnodal, postsubnodal spaces preserved, mostly not aligned; RP2 origin 6.5 cells distal to origin of IR2; IR2 origin at subnodus, on RP1-2 as in diagnosis; RP3-4: origin in distal part of middle third between arculus, nodus; arculus just proximal to Ax2; Ax0 not detected; no crossvein O in preserved portion; no major vein zigzags in preserved portions; CuA–A space with four, possibly five cells wide at widest (between levels of origins of IR1, RP2).

Etymology. The specific epithet is the neuter form of the Latin angustus (- a, - um) meaning “narrow”, referring to the distinctive wing shape of the species.

Range and age. McAbee, BC, Canada, mid-Ypresian.

Figures

FIGURE 36. Okanagrion angustum holotype, RBCM.EH2017.050.11.2491. A, photograph; B, drawing. Both to scale, 5 mm.