Okanagrion beardi 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 : 47-50

Okanagrion beardi Archibald & Cannings , new species

Figs. 21–22 .

Diagnosis. Wings separated from those of all other Okanagrion species but O. dorrellae by MP, CuA distinctly divergent near margin [others: MP-CuA space remaining narrow; O. dorrellae : widening, but less distinctly as CuA zigzagged distally ( O. angustum , not known)]; from all others except O. angustum by IR2 originating on RP1-2 [others: between RP1-2, RP3-4]; from O. angustum by Ax1 to nodus shorter, 6.5 mm (holotype; paratype 1: almost 6 mm, smaller wing, but proportions match holotype) [ O. angustum : 7.5 mm]; from O. dorrellae by MP linear to margin [ O. dorrellae : zigzagged near margin]; from O. liquetoalatum , O. dorrellae by wing shape: length (arculus to apex) / maximum width 3.1 [ O. liquetoalatum : 2.6; O. dorrellae 3.7; others similar to O. beardi ( O. lochmum , O. worleyae , O. angustum not comparable by preservation)].

Further separated by colouration (sex unknown): proximal approx. 2/5 hyaline, dark apical to this except narrow lighter fascia just distal to mid-way between nodus, pterostigma, extending from anterior margin to close to posterior margin; size and extent of light fascia differs from: O. hobani about twice or more as wide, extending to or almost to posterior margin; O. angustum apparently similar to O. hobani as preserved; O. threadgillae notably narrower, extending to mid-wing; O. dorrellae similar width, probably extending to mid-wing (but damage in this region); O. lochmum , similar to O. beardi ; O. liquetoalatum : hyaline throughout; O. worleyae : lightly infuscate throughout known wing.

Type material. Holotype: F-791 (part only) ( Fig. 21 ): One complete wing and portions of two or three others; possibly part of one eye; part of damaged thorax preserved in lateral aspect; at least two pieces of abdomen present; collected at the McAbee Hoodoo Face beds, collector and date unknown; housed in the Thompson Rivers University collections. Paratype 1: RBCM P1546 ( Fig. 22 ): a head, thorax, bits of some legs, proximal-most portion of the abdomen, well-preserved forewing and proximal portion of a hind wing; coated with shellac; collected at the McAbee Hoodoo Face beds, vi.1998 by unknown grade 8 or 9 student, donated by Graham Beard; in the Royal British Columbia Museum collections .

Description. Holotype, F-791, forewing. Almost complete, missing tiny portions of the apex and proximal to the nodus. Shape: oval distal to nodus, symmetrical from lateral mid-line; length: 31.5 mm, arculus to apex: about 27.7 mm, nodus to apex: about 22.7 mm, origin of RP2 to apex: 18.2 mm, arculus to base of pterostigma: 22.0 mm, nodus to base of pterostigma: 16.8 mm, nodus at 29% wing length; width 8.3 mm. Colouration as in diagnosis. Pterostigma anterior, posterior margins oblique, 3.5 times longer than wide, subtends 6.5 cells, no oblique brace vein. 35 crossveins in postnodal space (complete), none hyperstigmal, crossveins in postsubnodal space not aligned. Maximum three cells wide distal to pterostigma in costal space (partially preserved). RA–RP1 space narrows near margin. RP1–IR1 space becomes two cells wide unknown number of cells from origin by preservation. IR1 origin eight cells distal to origin of RP2. IR1–RP2 space becomes two cells wide unknown number of cells origin by preservation. RP2 origin six cells distal to origin of IR2. IR2 origin very close to subnodus; close to, appears to arise from RP1-2. RP3-4 origin about 2/3 from arculus to nodus. Ax0 present. Arculus close to, immediately proximal to Ax2. No crossvein O. All main veins linear other than IR1 proximally. MP, CuA divergent at terminus on posterior margin. CuA–A space with maximum five cells wide.

Paratype 1, RBCM P1546. Head ( Fig. 10 M , Table 1 ): relatively well preserved in dorsal aspect but details obscure; labrum/clypeus area damaged. In dorsal view about 4.1 mm across eyes at widest part, with rear margin expanded somewhat postero-laterally; approximate length from anterior edge of antefrons to posterior of occiput 1.5 mm; at level of hind ocelli distance between eyes about 1.2 mm, single eye roughly 1.5 mm wide, 2.0 mm long. Thorax: lateral view; colouration dark, apparently with narrow pale stripe on mesopleural suture, any other patterns obscure; pieces of legs poorly preserved. Forewing: as in holotype except length: 31.6 mm, arculus to apex: 26.5 mm, nodus to apex: 21.7 mm, origin of RP2 to apex: 16.6 mm, arculus to base of pterostigma: 21.0 mm, nodus to base of pterostigma: 16.2 mm; width 7.7 mm; nodus at 25% wing length. Colouration mostly obscured by applied shellac, but as apparent is consistent with holotype. Pterostigma: 5.5 cells subtend, length 3.5 times width. Postnodal space with 36 crossveins (probably complete), distal-most one hyperstigmal. IR1 origin seven cells distal to origin of RP2 ; IR1– RP2 space becomes two cells wide six or seven cells (unclear by preservation) distal to origin by preservation. RP2 origin nine cells distal to origin of IR2. Ax0 not detected. CuA–A space unknown number of cells wide by preservation, but appears similarly wide as holotype. Abdomen: segments 1 and 2 preserved in lateral aspect; base of abdomen relatively slender; irregular ventral margin of segment 2 may indicate presence of secondary male genitalia but sex of specimen undetermined .

Etymology. The specific epithet is a patronymic formed from the surname of Graham Beard, the donor of paratype 1, recognising his contribution.

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

Figures

FIGURE 10. Heads of Zygoptera (A, B) and comparative Anisoptera, Anisozygoptera, Tarsophlebiidae, Stenophlebiidae (C– H); and Cephalozygoptera (I–Q).A, Zygoptera, Heteropodagrion superbum Ris redrawn from Fig. 318 of Garrison et al. (2010); B, Zygoptera, Minagrion ribeiroi (Santos) redrawn from Fig. 1842 of Garrison et al. (2010); C, Anisoptera, Gomphidae, Cyanogomphus waltheri Selys redrawn from Fig. 383 of Garrison et al. (2006); D, Anisozygoptera, Epiophlebia laidlawi Tillyard redrawn from Fig. 2 of Büsse (2016); E, Anisoptera, Aeshnidae, Limnetron antarcticum Förster redrawn from Fig. 16 of Garrison et al. (2006); F, Stenophlebia sp. redrawn from Tillyard & Fraser 1940, Fig, 4C; G, Tarsophlebiidae, Tarsophlebia eximia Hagen redrawn from Fleck et al. (2004) Fig. 1C; H, photograph of Tarsophlebia eximia in MCZ collections; I, Sieblosia jucunda redrawn from Hagen (1858, Plate 24, Fig. 1); J, Cephalozygoptera incertae sedis SR 14-003-004; K, Phenacolestes parallelus UCM-4545; L, Okanopteryx macabeensis, GSC 141101; M, Okanagrion beardi paratype 1, RBCM P1546; N, Okanopteryx fraseri GSC 141104; O, Okanopteryx macabeensis F-790; P, Dysagrion fredericii redrawn from Scudder 1890, plate 6, Fig. 10; Q, Dysagrion fredericii redrawn from Scudder 1890, plate 6, Fig. 2. G and H, I, J to O to scales, all 5 mm; others, originals without scales.

FIGURE 21. Okanagrion beardi holotype, F-791. A, photograph; B, drawing. Small green arrow indicates IR2 originating on RP1-2. Both to scale, 5 mm.

FIGURE 22. Okanagrion beardi paratype 1. RBCM P1546. A, drawing; B, photograph. Both to scale, 5 mm.