Eocene Okanagan Highlands Research Articles

Fossil weaver ants (Hymenoptera, Formicidae, Oecophyllini) of the early Eocene Okanagan Highlands of far-western North America

Abstract We examine the fossil weaver ants (Formicidae, Formicine, Oecophyllini) of the early Eocene Okanagan Highlands fossil localities of British Columbia, Canada and Washington, United States of America, naming Eoecophylla quilchenensisn. gen. et sp. from Quilchena (British Columbia), formally transferring Camponotites kraussei Dlussky and Rasnitsyn (Republic, Washington) to the genus Oecophylla Smith, F., and describing but not naming a worker (McAbee, British Columbia), treated as Oecophyllinisp. A. These are the oldest known Oecophyllini (Oecophylla + Eoecophylla) and Oecophylla. Forewing vein stubs of E. quilchenensis and its well-developed hind wing vein M are plesiomorphies; this M is unique within the subfamily, suggesting Oecophyllini is sister to other Formicine. The head shape of O. kraussein. comb. indicates a close relationship to Oecophylla longiceps Dlussky from Eocene Messel, Germany. The ant Titanomyrma Archibald et al. is also known from the Okanagan Highlands and Messel, consistent with Late Cretaceous/early Paleogene intercontinental dispersal. We discuss possible host plants and trophobionts of these ants. Although Okanagan Highlands localities were cooler than the Paleotropical range of modern Oecophylla, their presence there might be explained by mild winters without significant frost.

Cimbicidae (Hymenoptera, 'Symphyta') in the Paleogene: revision, the new subfamily Cenocimbicinae, and new taxa from the Eocene Okanagan Highlands.

We erect the Cenocimbicinae, a new subfamily of Cimbicidae (Hymenoptera, Symphyta), restricted to the Selandian Menat Formation of France, the oldest occurrence of the family, and the Ypresian Okanagan Highlands of far-western North America. We describe new taxa from the Okanagan Highlands: Allenbycimbex morrisae gen. et sp. nov. and Leptostigma n. gen. with seven new species: L. alaemacula n. sp., L. brevilatum n. sp., L. fasciatum n. sp., L. longiclava n. sp., L. longipallidum n. sp., L. longitenebricum n. sp., and L. proxivena n. sp. We revise the Cimbicidae from the Ypresian Green River Formation and the Priabonian Florissant Formation, both in Colorado, USA. The oldest fossil of a modern cimbicid subfamily appears with a single pachylostictine specimen in the Green River Formation, and all Cimbicidae are in modern subfamilies after the Ypresian (we did not examine one larva known from Priabonian Baltic amber). Pseudocimbex clavatus Rohwer 1908 from the Florissant Formation is not a cimbicid; we treat it as Tenthredinoidea incertae sedis. We transfer Cimbex vetusculus Cockerell to Floricimbex n. gen.

The early Eocene flora of Horsefly, British Columbia, Canada and its phytogeographic significance

About forty species, including a bryophyte, ferns, conifers, Ginkgo, and over 35 angiosperms, are recognized based on compression-impression remains from the early Eocene of Horsefly, British Colombia, Canada. This flora is in the north central part of a chain of late early Eocene fossil assemblages known as floras of the “Okanagan Highlands” (= “Okanogan Highlands” in the US). These floras extend from north central British Columbia, Canada southeast to Republic, Washington, USA. The Horsefly flora shows similarities to other Eocene Okanagan Highlands floras, such as McAbee, Falkland, Thomas Ranch and Republic, but with some additional rare taxa. In the broader sense, the Horsefly flora can be compared with early and middle Eocene floras of eastern Asia and midcontinental North America, but shares fewer elements with Europe. Ginkgo, Metasequoia, Pinus, Palaeocarpinus, ulmaceous leaves and Deviacer are shared with northeastern China as well as western North American sites. Fagopsis, Macginitiea, Dipteronia, Florissantia, Sassafras and Lagokarpos also occur in other western North American Eocene floras and Koelreuteria and Jenkinsella with Eocene paleofloras of China. These comparisons demonstrate probable floristic exchange between northwestern North America and northeastern China via a Beringian route during the late early Eocene.

The early Eocene Eourocerus anguliterreus gen. et sp. nov (Hymenoptera, Siricidae) from Republic, Washington.

A new fossil horntail wood wasp (Hymenoptera, Symphyta, Siricidae), Eourocerus anguliterreus gen. et sp. nov. from an early Eocene Okanagan Highlands locality at Republic, Washington, USA is described. Its forewing is most like that of the extant and fossil genus Urocerus Geoffroy, 1785. It is the third fossil siricid described from North America. We treat Xeris dorbnikensis Manukyan Smirnova, 2021 and Xeris sp. of Manukyan Smirnova (2021) as Urocerus dorbnikensis (Manukyan Smirnova, 2021), comb. nov. and Urocerus sp., both tentatively belonging to the genus, Urocerus klebsi Brues, 1926 as Xeris klebsi (Brues, 1926) comb. nov., and Afrotremex or Eriotremex sp. of Wedmann (1998) as a species of Eriotremex Benson, 1943. A key to extant and extinct genera of Siricinae by forewing characters is given.

The Palaeorehniidae (Orthoptera, Ensifera, Zeuneropterinae), and new taxa from the early Eocene Okanagan Highlands, western North America.

We revise the subfamily Zeuneropterinae (Orthoptera, Ensifera) and treat it as the family Palaeorehniidae Zeuner stat. nov. We restore the late Eocene Palaeorehnia Cockerell from Florissant, Colorado, USA to the taxon and describe two new genera and species in it: Ypopteron nicola n. gen., n. sp. from Quilchena, British Columbia, Canada and Republicopteron douseae n. gen., n. sp. from Republic, Washington, USA. Given current knowledge, Palaeorehniidae appears intermediate between the Stenopelmatoidea and the Hagoidea (s.s.).

The first Odonata from the early Eocene Allenby Formation of the Okanagan Highlands, British Columbia, Canada (Anisoptera, Aeshnidae and cf. Cephalozygoptera, Dysagrionidae)

Abstract Fossil insects have been collected and described from the early Eocene Allenby Formation of southern British Columbia, Canada for over a century, but these have never included Odonata. We describe the first members of that order from the formation: Allenbya holmesae, new genus and species, most likely belonging to the Dysagrionidae (suborder Cephalozygoptera), and a torn, folded, and incomplete wing assigned to the Aeshnidae (suborder Anisoptera) that cannot be identified below family level. In other regional deposits of the early Eocene Okanagan Highlands series of lacustrine shales, the Dysagrionidae is by far the most common odonate family, followed by the Aeshnidae.

A new genus and species of Euphaeidae (Odonata, Zygoptera) from the early Eocene Okanagan Highlands locality at Republic, Washington, U.S.A.

We describe Republica weatbrooki, a new genus and species of damselfly (Odonata, Zygoptera, Euphaeidae, Eodichromatinae) from the early Eocene (Ypresian) fossil locality at Republic, Washington, U.S.A. Its single specimen is the sole damselfly known from the Okanagan Highlands series of localities in far-western North America.

The Cephalozygoptera, a new, extinct suborder of Odonata with new taxa from the early Eocene Okanagan Highlands, western North America.

We describe the Cephalozygoptera, a new, extinct suborder of Odonata, composed of the families Dysagrionidae and Sieblosiidae, previously assigned to the Zygoptera, and possibly the Whetwhetaksidae n. fam. The Cephalozygoptera is close to the Zygoptera, but differs most notably by distinctive head morphology. It includes 59 to 64 species in at least 19 genera and one genus-level parataxon. One species is known from the Early Cretaceous (Congqingia rhora Zhang), possibly three from the Paleocene, and the rest from the early Eocene through late Miocene. We describe new taxa from the Ypresian Okanagan Highlands of British Columbia, Canada and Washington, United States of America: 16 new species of Dysagrionidae of the existing genus Dysagrion (D. pruettae); the new genera Okanagrion (O. threadgillae, O. hobani, O. beardi, O. lochmum, O. angustum, O. dorrellae, O. liquetoalatum, O. worleyae, all new species); Okanopteryx (O. jeppesenorum, O. fraseri, O. macabeensis, all new species); Stenodiafanus (S. westersidei, new species); the new genus-level parataxon Dysagrionites (D. delinei new species, D. sp. A, D. sp. B, both new); and one new genus and species of the new family Whetwhetaksidae (Whetwhetaksa millerae).

Fossil dragonflies (Odonata: Anisoptera) from the early Eocene Okanagan Highlands, western North America

AbstractWe describe the first dragonflies (Odonata: Anisoptera) from the early Eocene Okanagan Highlands of far-western North America from nine fossils. Six are assigned to five species in four new, named genera of Aeshnidae:Antiquiala snyderaenew genus and species,Idemlinea versatilisnew genus and species,Ypshna brownleeinew genus and species,Ypshna latipennatanew genus and species, andEoshna thompsonensisnew genus and species; we treat one as Aeshnidae genus A, species A; one is assigned to Gomphidae:Auroradraco eosnew genus and species; and we treat a ninth, fragmentary fossil of unknown family affinity as Anisoptera indeterminate genus A, species A, which represents a seventh genus and eighth species. The dominance of Aeshnidae is consistent with other Paleocene and Eocene fossil localities.Auroradraco eosis the only fossil Gomphidae in the roughly 66-million-year gap between occurrences in mid-Cretaceous Burmese amber and the early Oligocene of France.Ypshnaappears close toParabaissaeshna ejerslevensefrom the early Eocene Fur Formation of Denmark; this is not surprising given Holarctic intercontinental connections at this time and a growing list of insect taxa shared between the Okanagan Highlands and the Fur Formation.

Modernisation of the Hymenoptera: ants, bees, wasps, and sawflies of the early Eocene Okanagan Highlands of western North America

AbstractMost major modern families of Hymenoptera were established in the Mesozoic, but the diversifications within ecologically key trophic guilds and lineages that significantly influence the character of modern terrestrial ecosystems – bees (Apiformes), ants (Formicidae), social Vespidae, parasitoids (Ichneumonidae), and phytophagous Tenthredinoidea – were previously known to occur mostly in the middle to late Eocene. We find these changes earlier, seen here in the early Eocene Okanagan Highlands fossil deposits of western North America. Some of these may have occurred even earlier, but have been obscured by taphonomic processes. We provide an overview of the Okanagan Highlands Hymenoptera to family level and in some cases below that, with a minimum of 25 named families and at least 30 when those tentatively assigned or distinct at family level, but not named are included. Some are poorly known as fossils (Trigonalidae, Siricidae, Peradeniidae, Monomachidae), and some represent the oldest confirmed occurrences (Trigonalidae, Pompilidae, Sphecidaesensu stricto, Peradeniidae, Monomachidae, and possibly Halictidae). Some taxa previously thought to be relictual or extinct by the end of the Cretaceous (Angarosphecidae, Archaeoscoliinae, some Diapriidae) are present and sometimes abundant in the early Eocene. Living relatives of some taxa are now present in different climate regimes or on different continents.

An unusual new fossil genus probably belonging to the Psychopsidae (Neuroptera) from the Eocene Okanagan Highlands, western North America.

The new genus and species Ainigmapsychops inexspectatus gen. et sp. nov. is described from the early Eocene Okanagan Highlands locality at Republic, Washington, U.S.A. We preliminarily assign it to the Psychopsidae; however, its venation is unusual within this family, particularly by its pectinate branches of AA1 originating at a steep angle, a character state more suggestive of the Osmylidae.

The Eocene apex of panorpoid scorpionfly family diversity

The scorpionfly (Mecoptera) superfamily Panorpoidea underwent an Eocene radiation, replacing the extinct Mesozoic orthophlebiid grade and reaching its greatest family-level diversity: Panorpidae, Panorpodidae, Austropanorpidae, Holcorpidae, Dinopanorpidae, and a new family proposed here, the Eorpidae. Only the Panorpidae and Panorpodidae survived the Eocene and persist to the present day. This cluster of family extinctions is exceptional within Cenozoic insects. The Eorpidae includes at least one new genus and three new species described here from four localities of the early Eocene Okanagan Highlands of British Columbia, Canada, and Washington, U.S.A.:Eorpa ypsipedan. gen. n. sp. (McAbee and possibly Falkland, BC, Canada; and Republic, WA, U.S.A.),Eorpa elverumin. gen. n. sp. (Republic), andEorpa jurgenin. gen. n. sp. (Quilchena, BC). Some of the other fragmentary and poorly preserved specimens might represent further new species. We propose that the apex of Panorpoid family diversity ended by pressures from post-Eocene icehouse world climatic stress and the rise to ecological dominance of ants, some of which would have provided strong competition in scavenging for dead arthropods.

Revision of the scorpionfly family Holcorpidae (Mecoptera), with description of a new species from Early Eocene McAbee, British Columbia, Canada

The scorpionfly family Holcorpidae (Mecoptera) has been informally discussed since the early 1960’s, but a detailed treatment in accordance with the provisions of the International Code of Zoological Nomenclature for naming families was not provided until Willmann did so in 1989; he is recognized as author of the family. The Holcorpidae concept is revised here based on examination of its two specimens of Holcorpa maculosa from the Late Eocene of Florissant, Colorado, and a third, new specimen from the Early Eocene Okanagan Highlands locality at McAbee, British Columbia, Canada. This new specimen belongs to a second, new species, which is described here, Holcorpa dillhoffi n. sp.

New Cimbrophlebiidae (Insecta: Mecoptera) from the Early Eocene at McAbee, British Columbia, Canada and Republic, Washington, USA

Four new scorpionfly species of the family Cimbrophlebiidae (Mecoptera) are described in the genus Cimbrophlebia Willmann from two localities of the far-western North American Early Eocene Okanagan Highlands: C. flabelliformis sp. n. and C. leahyi sp. n. from McAbee, British Columbia, Canada; and C. brooksi sp. n. and C. westae, sp. n. from Republic, Washington, U.S.A. A further, partially preserved specimen of a large cimbrophlebiid from McAbee is treated as Cimbrophlebia sp. A. This is the first record of the extinct family in the Western Hemisphere, which was previously known with confidence from the Early Eocene of Denmark (C. bittaciformis Willmann) and the Jurassic of Germany (Malmocimbrophlebia buergeri Bechly & Schweigert and an undescribed genus and species); Telobittacus fragosus Zhang from Early Cretaceous of China may also belong to the family. These Okanagan Highlands occurrences further reflect Early Eocene cross-North Atlantic distributions that have been well documented in plants and mammals, and are increasingly seen in insects.

Tertiary giant lacewings (Neuroptera: Polystoechotidae): Revision and description of new taxa from western north America and Denmark

Synopsis A preliminary definition of the Polystoechotidae (Insecta, Neuroptera) based on wing characters is provided. Tertiary Polystoechotidae are revised; the genus Palaeopsychops Andersen (10 species) and the new collective genus Polystoechotites gen. n. (6 species) are recognised. Ten new species (eight named) are described from the earliest Early Eocene Fur Formation (Denmark) and the Early to early Middle Eocene Okanagan Highlands (Quilchena and Horsefly River, British Columbia, Canada and Republic, Washington, USA): Palaeopsychops quadratus sp. nov. (Fur Formation); Palaeopsychops setosus sp. nov. (Horsefly River); Palaeopsychops marringerae sp. nov., Palaeopsychops timmi sp. nov., Polystoechotites lewisi gen. et sp. nov., Polystoechotites barksdalae gen. et sp. nov., Polystoechotites falcatus gen. et sp. nov. (Republic); Palaeopsychops douglasae sp. nov., Polystoechotites sp. A, Polystoechotites sp. B (Quilchena). Polystoechotes piperatus Cockerell from Late Eocene of Florissant (Colorado, USA) is assigned to Polystoechotites. Neuroptera incertae sedis sp. A (Republic) is determined as either an aberrant polystoechotid, or belonging to a family of psychopsid‐like Neuroptera. Palaeopsychops setosus sp. nov. bears a dense cover of macrotrichia across a portion of the wing membrane, not previously known in the order. Extended floating time of polystoechotids increased negative taphonomic bias, in most depositional settings probably lowering their fossil assemblage representation. In some, taphonomic factors such as the presence of mat‐forming organisms may have enhanced their fossil representation to greater than their community representation. This scenario is proposed for the Fur Formation, consistent with lithological evidence and palaeogeographic reconstruction. Dispersal of Palaeopsychops between Denmark and the Okanagan Highlands (direction unknown) was probably by the North Atlantic route, not before the late Palaeocene, during periods of continuous land connection between North America and northern Europe. Polystoechotidae in the Eocene, as today, appear to have ranged in forested regions of microthermal to lower mesothermal climate.

Systematics and phytogeography of selected Eocene Okanagan Highlands plants

The diverse Early to Middle Eocene Okanagan Highlands floras of south central British Columbia and northeastern Washington reflect a time of rapid evolution and the early radiation of many dicot families that are currently significant elements of temperate floras. Recent studies of the Republic, Washington flora (Klondike Mountain Formation) and related Okanagan floras in British Columbia have documented both the earliest, and sometimes the only, known fossil occurrences of genera. Today many once more widespread taxa are restricted, particularly to Asian and (or) eastern North American refugia. Examples include members of the families Betulaceae (birch, hazelnut), Rosaceae (rose), Hamamelidaceae (witch hazel), and the endemic Asian family Trochodendraceae. Earliest occurrences are noted for Neviusia (Rosaceae), Trochodendron (Trochodendraceae), Corylus and Carpinus (both Betulaceae). The first unequivocal leaf records of Corylopsis and Fothergilla (both Hamamelidaceae), and two new Eocene species of the extinct fruit Palaeocarpinus (Betulaceae) are also recognized. Today, Trochodendron and Corylopsis are restricted to Asia, whereas Neviusia and Fothergilla, genera with close Asian relatives, occur only in North America. Corylus johnsonii from Republic is most similar to the extant Asian species C. heterophylla, C. wangii, and C. ferox. Neviusia leaves from One Mile Creek near Princeton, British Columbia are more similar to N. cliftonii, an endemic from Mount Shasta, California, than to N. alabamensis of southeastern North America. A better documentation of the Okanagan Highlands floras is essential to our understanding of the evolution of North American temperate floras and the nature of Asian – North American disjunct taxa.

Regional and local vegetation community dynamics of the Eocene Okanagan Highlands (British Columbia – Washington State) from palynology

Palynofloras from the middle Early to early Middle Eocene Okanagan Highlands (northern Washington State and southern British Columbia) are used to reconstruct vegetation across a broad upland Eocene landscape. In this preliminary report, forest floristic composition is reconstructed using palynological analysis of sediments from Republic, Washington; localities of the Allenby Formation in the Princeton region (Hospital Hill, One Mile Creek and Summers Creek Road), Hat Creek, McAbee, Falkland, Horsefly, and Driftwood Canyon, British Columbia. Wind-dispersed taxa were dominant in all samples, consistent with floras preserved in lacustrine and paludal depositional environments. Pseudolarix was dominant in five of the floras, but Abies (Falkland) or Ulmus (Republic Corner Lot site) were dominant in individual samples for some floras. Betulaceae were dominant for McAbee (Alnus) and Allenby Formation (Betula), matching megafloral data for these sites. Some taxa common to most sites suggest cool conditions (e.g., Abies, other Pinaceae; Alnus, other Betulaceae). However, all floras contained a substantive broad-leaved deciduous element (e.g., Fagaceae, Juglandaceae) and conifers (e.g., Metasequoia) indicative of mesothermal conditions. Palms were only abundant in the Hat Creek coal flora, with very low counts recorded for the Falkland, McAbee, and Allenby Formation sites, suggesting that they were rare in much of the landscape and likely restricted to specialized habitats. Thermophilic (principally mesothermal) taxa, including palms (five sites) and "taxodiaceous" conifers, may have occurred at their climatic limits. The limiting factor controlling the regional distribution of thermophilic flora, which include primarily wetlands taxa, may be either climatic or edaphic.

New Dinopanorpidae (Insecta: Mecoptera) from the Eocene Okanagan Highlands (British Columbia, Canada and Washington State, USA)

Six new species of the extinct family Dinopanorpidae (Mecoptera) are described in the new genus Dinokanaga gen. nov. from five Early (and early Middle?) Eocene Okanagan Highlands localities in British Columbia and Washington State. These are Dinokanaga hillsi sp. nov., D. wilsoni sp. nov., D. dowsonae sp. nov., D. andersoni sp. nov., D. sternbergi sp. nov., and D. webbi sp. nov. The family Dinopanorpidae is previously known only from a hind wing of Dinopanorpa megarche Cockerell, and an undescribed species of Dinopanorpa, both from the Paleogene of Primorye (Maritime Province) in Pacific coastal far-eastern Russia. The family includes mostly large species, with forewings up to 43 mm in length. Dinopanorpidae is particularly distinguished by a long R1 vein in both the fore- and hind wings, extending almost to the wing apex and bending posteriad distally. Their wings are mostly dark with light bands and spots; have many to extremely dense crossveins; and an expanded costal space in the basal quarter of the forewing, which is more developed in larger species. The rostrum is extended; the medigynium is without tongue-shaped structures.

The McAbee flora of British Columbia and its relation to the Early-Middle Eocene Okanagan Highlands flora of the Pacific Northwest

Megafossils and pollen data are used to compare the flora found at the McAbee site, located near the town of Cache Creek, British Columbia, to six other well-collected Eocene lacustrine floras of Washington and western British Columbia. A diverse flora is found at McAbee consisting of at least 87 taxa. Gymnosperms are common, including sixteen separate species, 14 conifers and two ginkgos. A minimum of 67 angiosperm genera are represented in the flora, many yet to be described. The dominant dicotyledonous elements of the leaf assemblage at McAbee include Fagus (also represented by nuts and cupules) with Ulmus and representatives of the Betulaceae, especially Betula and Alnus. The confirmation of Fagus, also rarely found from sites at Princeton, British Columbia, and Republic, Washington, provides the oldest well-documented occurrence of the genus, predating the Early Oligocene records of Fagus previously reported for North America, Asia, and Europe. Data provided by pollen analysis broadens our knowledge of the McAbee flora. Angiosperm pollen typically predominates over gymnosperms with the Ulmoideae and Betulaceae being the most common angiosperm pollen types. Members of the Pinaceae dominate the gymnosperm pollen record. Paleoclimatic estimates for McAbee are slightly cooler than for the Republic and Princeton localities and thermophilic elements, such as Sabal found at Princeton or Ensete and Zamiaceae found at Republic are not known from McAbee.

Fossil biotas from the Okanagan Highlands, southern British Columbia and northeastern Washington State: climates and ecosystems across an Eocene landscape

The late Early to early Middle Eocene Okanagan Highlands fossil sites, spanning ~1000 km north–south (northeastern Washington State, southern British Columbia) provide an opportunity to reconstruct biotic communities across a broad upland landscape during the warmest part of the Cenozoic. Plant taxa from these fossil sites are characteristic of the modern eastern North American deciduous forest zone, principally the mixed mesophytic forest, but also include extinct taxa, taxa known only from eastern Asian mesothermal forests, and a small number of taxa restricted to the present-day North American west coast coniferous biome. In this preliminary report, paleoclimates and forest types are reconstructed using collections from Republic in Washington State, USA., and Princeton, Quilchena, Falkland, McAbee, Hat Creek, Horsefly, and Driftwood Canyon in British Columbia, Canada. Both leaf margin analysis (LMA) and quantitative bioclimatic analysis of identified nearest living relatives of megaflora indicated upper microthermal to lower mesothermal moist environments (MAT ~10–15 °C, CMMT > 0 °C, MAP > 100 cm/year). Some taxa common to most sites suggest cool conditions (e.g., Abies, other Pinaceae; Alnus, other Betulaceae). However, all floras contain a substantive broadleaf deciduous element (e.g., Fagaceae, Juglandaceae) and conifers (e.g., Metasequoia) with the bioclimatic analysis yielding slightly higher MAT than LMA. Thermophilic (principally mesothermal) taxa include various insects, the aquatic fern Azolla, palms, the banana relative Ensete, taxodiaceous conifers, Eucommia and Gordonia, taxa which may have occurred near their climatic limits. The mixture of thermophilic and temperate insect and plant taxa indicates low-temperature seasonality (i.e., highly equable climate).