Pa/eo111ulo,~ical Juurnal, vbl. 33. Nu. 4, /999, рр. 403-405. Traщlatedfmm Paleontoloкicheskii Zhumal, No. 4, 1999, рр.67-{)9. Onginul Russian Text Соругi.~!11 © /1)99 h.v Si11itsl1enkмa. Englis/1 li'anslation Copyгigl1t © 1999 hy МАИК "Наука/ /11te1periodica" (Russia)

А New Species of the Extant Genus from the Еосепе of North America (lnsecta: Ephemerida = Ephemeroptera: Neoephemeridae) N. D. Sinitshenkova Paleontological lnstitute, Russian Academy o.f Sciences, ul. Pmfsoyu:naya 123, Моsсон'. 117868 Russia Received April 20, l 998

Abstract-A new mayfly species Neoeplzemem antiqua sp. nov. (Neoephemeridae) is described from the Eocene of North America (the RepuЫic locality). This is а first fossil find of the genus Neoephemaa, and the oldest record of the family Neoephemeridae.

INTRODUCТION cies was already fouпd assigпed to the geпus Potaman­ thellus. This рhепоmепоп was explained Ьу the isola­ Dr W.C. Wehr from the Burke Museum of Natural tioп in the Cretaceous апd Early Paleogeпe of the west­ History апd Culture, Seattle, Washiпgtoп, USA ern part of North America (faunistically associated with (UWBM) kiпdly preseпted to me for study three iпsect Asia) from the eastern part (associated with Europe). It specimeпs from the Кloпdike Mouпtain Formatioп was assumed that two extaпt phyletic liпeages within near RepuЫic, Washiпgtoп: опе пymph determiпed as Neoephemeridae had separated due to the geographical а stonefly, and two mayfly пymphs. One mayfly пymph isolatioп of their ancestors, the Potamanthellus lineage (UWBM, 57158) was previously reported as Heptage­ оп the Asiamerican laпd and the Neoephemeгa+Ocher­ niidae inceгtae generis ("?Stenonema or Heptagenia;" nмa lineage on the Euramericaп laпd (Вае and McCaf­ Lewis апd Wehr, 1993). The specimen (part and couп­ ferty, 1998). However, а пеw fiпd of fossil Neoephem­ terpart) is rather poorly preserved, allowiпg coпfirma­ era iп the westem Nearctic conflicts with this hypothe­ tion but without delineation. The second, well pre­ sis, опсе more demoпstrating how uпreliaЫe the served mayfly nymph (UWВM, 76324) belongs to а paleoblogeographic coпstructions based оп the new spccies of the family Neoephemeridae. The third preseпt-day distribution of the group are. This find nymph (UWBM, 57138), misidentified as а stoпefly, is shows that in the Paleogene both phyletic lineages of in fact а mayfly, possessiпg three caudal filaments, the the family occuпed iп western North America (where paracercus being less distiпct than the cerci in the Neoephemeridae поw became extinct), апd that there impression, loпg forewing pads and short hiпdwing are no reasoпs to associate their separatioп with the iso­ pads (Fig. la). This fragmentariJy preserved specimen latioп of Asiamerica and Euramerica. can Ье ideпtified up to order only; it is not coпspecific with either of the above-meпtioпed опеs. The fossil iпsects from the RepuЫic locality origi­ The small family the Neoephemeridae comprises пate from the Middle Еосепе lake deposits filliпg the three genera and 12 species occurring in the N earctic RepuЫic graben, Washiпgtoп, апd beloпgiпg to the and Orieпtal Regions (Edmunds et а/" 1979; Вае and Lower Кlondike Mountain Formatioп (Wolfe and Мс Cafferty, 1998). Up to the present only опе fossil Wehr, 1987, 1991 ). These iпsects 'Nere collected a]ong neoephemerid species was knowп, Potamanthellus with а rich leaf flora (Wolfe and Wehr, 1987, 1991; гuЬiensis Lewis from the Oligoceпe (or termiпal Wehr and Schorn, 1992), freshwater crustaceans, апd Eocene) of the Rubl River Basin, Мопtапа, USA freshwater and aпadromous fishes (Wilson, 1978; (Lewis, 1977). The genus Potamanthellus Lestage is Joseph, 1986). Composition of the flora indicates that now restricted to the OrieпtaJ Region. The genus the sediments were f ormed in а mouпtaiп lake under а Neoephemeгa is reported here for the first time iп the humid and warm climate. beiпg fossil state, this find the oldest record of the Of 16 orders reported from the RepuЬlic Neoephemeridae. locality (Lewis, 1992; Wehr and Barksdale, 1996), five Liviпg Neoephemem species occur in the eastem iпclude water dweПers: Ephemeroptera, Odonata, Ple­ Nearctic апd westem Palearctic regions, in coпtrast to coptera, Hemiptera, and Trichoptera. However, if the Potamanthellus, поw restricted to ceпtral and eastern record of Plecoptera is based only оп the above-men­ Asia. The former distributioп of the farniJy was esseп­ tioned specimeп, this order should Ье excluded from tially unlike the modern опе. In the westem Palearctic the Jist. The Odoпata are represeпted with imagoes where пeoephemerids are now abseпt, опе Еосепе spe- опlу. There are по water dwelling forms among the

403 404 SINIТSHENKOV А et а/ .

Fig. 1. Mayfties from the Еосепе о[ RepuЫic (North America): (а) Ephemeroptera iпс. fam., пymph, specimen UWBM. 571 38; (Ь, с) Neoepl1emeгa antiqua sp. поv" пymph, holotypc UWВM, 76324 А0307В: (Ь) structшal dctails, (с) habitus,x 11.7. Scale tшit 2 шm. families of Coleoptera and Diptera given iп the list. (fore апd middle leg almost complete; all three caнdal Thus, aquatic iпsects are поt diverse iп this locality. The tilaments lacking apical portions); locality nr. Repub­ nymphs of liviпg Neoephemeгa inhablt slow ог moder­ lic, Washington, USA; Eocene, Lower Кlondike Moнп­ ately fast rivers, often occшring on submerged tree tain Formation. roots and trunks, more rarely uпder large ftat stones iп rapid currents or in moss (Edmunds et al., 1979; Вае Description (Figs. lb, lc). А пymph. The апd McCafferty, 1998). The пymph of pronotнm is almost four times as wide as loпg medially, from RepuЫic shows the typical reophiloнs habltus, wit\1 the lateral margins conspicuously dilated, antero­ characteristic of the members of this family as а whole. lateral angles formed into small acumiпate pюcesses, So far as both ideпtitiaЫe mayfly nymphs beloпg to and anterior margiп lacking submedian tнbercles. The reophilous groups and are represented Ьу unique tiпds, anterior angles of the mesonotum are provided with these remains are most рrоЬаЫу taphonomically small rouпded processes, its anterior margiп lacks sub­ allochtonous, the more so that are quite steno­ median tubercles. The fore legs are short, the middle Ьiotic апd develop опlу in the water bodies favouraЫe ones are consideraЫy loпger and broader. The plates of to aquatic insects iп general. operculate gills are subquadrate with the posterolateral angles rouпded and the diagoпal ridge well developed; SYSТEMAТIC PALEONTOLOGY they almost completely cover the fourth and tifth seg­ meпts . The abdominal segments are short, 3.4 times as Family Neoephemeгidae Тгаvег, 1935 wide as long, withoнt mediaп processes at the posteriol' Genus Neoephemera McDunnough, 1925 margin; the posterolateral angles of the sixth-пinth seg­ Neoephemera antiqua Sinitshenkova, sp. ПО\'. meпts are developed into strong spines, оп the sixth апd Е t у m о 1о g у. From Latin antiquus (old). seventh ones being nearly half segment long, оп the Но 1 о t у ре. UWBM, 76324 АО307В, well pre­ eighth and ninth ones sшpassing the next segmeпt. The served positive impression of а nymph from dorsal side cerci bear small spinules, Ьнt no long hairs.

PALEONTOLOGICAL JOURNAL Vol. 33 No. 4 1999 А NEW МА YFL У SPECIES OF ТНЕ ЕХТ ANT GENUS 405

М е а s u r е m е n t s (mm): body \ength of the Edmunds, G.F., Jr., Jensen, S.L., and Вешеr, L., The Mayflies nymph lackiпg head, 7.3; estimated totaJ body leпgth, ofNorth and Сепtга/ America, Minneapolis: Univ. of Minne­ са. 8.5. sota Press, 1979. С о m р а r i s оп . Distiпct from the liviпg species Joseph, N.L., Eocene Flora and Fauna Unearthed at Repub­ of the geпus iп the shorter proпotum with moderately lic, Wash. Geol. Newslett., 1986, vol. 14. no. 4, рр. 3-11. dilated lateral margiпs, smaller rouпded process at the Lewis, S.E., Two New Species of Fossil Mayflies anterolateral aпgles of the mesoпotum, апd аЬsепсе of (Ephemeroptera: Neoephemeridae and ) trom median processes at the posterior margiпs of the the Ruby River Basin (Oligocene) of Southwestem Moпtana, abdomiпal segmeпts. Proc. Entomol. Soc. Wash., 1977, vol. 79, рр. 583-587. R е m а r k s . The species is assigпed to the geпus Lewis, S.E., Insects ot· the Кloпdike Mouпtaiп Formation, оп Neoephemera based the presence of processes at the RepuЫic, Washiпgton, Wash. Geol., 1992, vol. 20. no. 3, anterolateral aпgles ot' the proпotum, of а diagoпal rib рр. 15-19. at the gill opercula, and the аЬsепсе of lateral setal rows on the caudal filameпts: however, it сап easily Ье distiп­ Lewis, S.E. and Wehr, W.C., Fossil Mayflies from RepuЫic, Washington, Wash. Geol" 1993, vol. 21, no. 1, рр. 35-37. guished from all the liviпg species Ьу the above-meп­ tioned characters. Wehr, W.C. and Barksdale, L.L., А Checklist of Fossil М а t е r i а 1 . Holotype. Insects from RepuЫic, Washiпgton, Wash. Geol" 1996, vol. 24, no. 2, р. 29.

Wehr, W.C. and Schorn, Н.Е., Curreпt Research оп Еосепе ACKNOWLEDGMENТS Conifers at RepuЫic, Washingtoп, Wash. Geol., 1992, The author is grateful to Dr W.C. Wehr (UWBM) vol. 20, no. 2, рр. 20-23. and Dr K.Yu. Eskov (Paleoпtological Iпstitute, Russiaп Wilson, М. У., Eohiodon и 1 oodгu.ffi n. sp. (Teleostei, Hiodon­ Academy of Scieпces, Moscow) for the opportuпity to tidae) from the Middle Еосепе Кlondike Mouпtaiп Forma­ study the mayfties from the RepuЬ\ic locality, апd to tion near RepuЬlic, Washiпgtoп, Canad. J. Eaгth Sci" 1978, A.N. Maziп (Paleoпtological Iпstitute) for the photo­ vol. 15, по. 5, рр. 679-686. graphs. Wolfe, J.A. and Wehr, W., Middle Eocene Dicotyledoпous Plants from RepuЬlic, Northeastern Washiпgton, US Geol. REFERENCES Surv. Bull., 1987, no. 1597, рр. 1-25. Вае, Y.J. and McCafferty, W.P., Phylogenetic Systematics Wolfe, J.A. and Wehr, W., Significance of the Eocene Fossil and Biogeography of the Neoephemeridae (Ephemeroptera: Plants at RepuЬlic, Washington, Wash. Geol., 1991, vol. 19, ), Aquatic lnsects, 1998, vol. 20, no. 1, рр. 35-68. по. 3, рр. 18-24.

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