New fossil mousebird (Aves: Coliiformes) with feather preservation provides insight into the ecological diversity of an Eocene North American avifauna

Coliiformes (mousebirds) are represented by just six extant species. These species, restricted to sub‐Saharan Africa, are all primarily frugivorous and are among the most sedentary of living birds. Previously described fossil Coliiformes preserving feather traces share the short, rounded wing shape of extant mousebirds. Along with osteological evidence, these observations have been proposed to support poor sustained flight capabilities across the stem mousebird lineage. We report a new species of Coliiformes from the early Eocene (51.66 ± 0.09 Ma) Fossil Butte Member of the Green River Formation, represented by one of the comparatively few fossils from these deposits preserving carbonized traces of the wing and tail feathering. Feather traces indicate an elongate, tapering wing shape similar to that of some extant aerial insectivores, and suggestive of a capacity for sustained and agile open‐air flight. Traces of the rectrices reveal the tail accounted for approximately two‐thirds of the total length of the bird, a proportion similar to that in living mousebirds. Phylogenetic analysis places the new species as a stem representative of Coliiformes, demonstrating for the first time that the two major clades of Coliiformes – Sandcoleidae and Colii – co‐occurred at Fossil Lake. Based on the recovered phylogeny, as well as the osteology and feathering of extant and fossil Coliiformes, the wing shape of the new species is interpreted as apomorphic. In addition to documenting unexpected morphological specialization within stem‐lineage Coliiformes, the new species adds yet another taxon to the emerging reconstruction of the diverse Paleogene avifauna from the tightly dated and nearly synchronous fossiliferous deposits of the Fossil Butte Member. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 685–706.     

A mousebird (Aves: Coliiformes) from the Eocene of England

Summary The first fossil mousebird (Aves, Coliiformes) known from the Eocene of England is described. This taxon,Eocolius walkeri gen. n. sp. n., is assigned to the order Coliiformes (mousebirds) on the basis of a character of the proximal ulna (large cotyla dorsalis). The degree of similarity between the preserved elements ofEocolius and those of the other known fossil and Recent taxa further support this conclusion. At present, this new taxon is considered to occupy an unresolved position near to the base of the coliiform ingroup; the phylogenetic position ofEocolius cannot be resolved further owing to a lack of preservation of diagnostic characters.

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Ein Mausvogel (Aves: Coliiformes) aus dem Eozän von England

Zusammenfassung Der erste fossile Mausvogel (Aves: Coliiformes) aus dem Eozän von England wird beschrieben. Dieses Taxon,Eocolius walkeri gen. n. sp. n., wird aufgrund von Merkmalen der proximalen Ulna (grosse Cotyla dorsalis) in die Ordnung Coliiformes gestellt. Darüber hinaus stützt der Grad der Üebereinstimmung zwischen den erhaltenen Skelettelementen vonEocolius und den anderen bekannten fossilen und rezenten Taxa diese Zuordnung. Zur Zeit nimmt dieses neue Taxon eine nicht näher aufgelöste Stellung an der Basis der Coliiformes ein. Das Fehlen diagnostischer Merkmale lässt keine sichere Zuordnung vonEocolius zu den ausgestorbenen Sandcoleidae oder den rezenten Coliidae zu.

     

New postcranial elements for the earliest Eocene fossil primate Teilhardina belgica

Teilhardina belgica is one of the most primitive fossil primates known to date and the earliest haplorhine with associated postcranials, making it relevant to a reconstruction of the ancestral primate morphotype. Here we describe newly discovered postcranial elements of T. belgica. It is a small primate with an estimated body mass between 30 and 60 g, similar to the size of a mouse lemur. Its hindlimb anatomy suggests frequent and forceful leaping with excellent foot mobility and grasping capabilities. It can now be established that this taxon exhibits critical primate postcranial synapomorphies such as a grasping hallux, a tall knee, and nailed digits. This anatomical pattern and behavioral profile is similar to what has been inferred before for other omomyids and adapiforms. The most unusual feature of T. belgica is its elongated middle phalanges (most likely manual phalanges), suggesting that this early primate had very long fingers similar to those of living tarsiers.     

Exceptional three-dimensional preservation and coloration of an originally iridescent fossil feather from the Middle Eocene Messel Oil Shale

A feather from the Eocene Messel Formation, Germany, has been demonstrated to have been originally structurally colored by densely packed sheets of melanosomes similar to modern iridescent feathers exhibiting thin-film diffraction. The fossil itself currently exhibits a silvery sheen, but the mechanism for generating this optical effect was not fully understood. Here we use scanning electron microscopy, electron probe microanalysis, and dual-beam focused ion beam scanning electron microscopy to investigate the source of the silvery sheen that occurs in the apical feather barbules. Focused ion beam scanning electron microscopy provides a powerful tool for studying three-dimensionality of nanostructures in fossils. Use of the method reveals that the flattened apical barbules are preserved almost perfectly, including smooth structural melanosome sheets on the obverse surface of the fossil feather that are identical to those that cause iridescence in modern bird feathers. Most of each apical barbule is preserved beneath a thin layer of sediment. The silvery sheen is generated by incoherent light diffraction between this sediment layer and melanosomes and, although related to the original iridescence of the feather, is not a feature of the feather itself. The reddish and greenish hues frequently exhibited by fossil feathers from the Messel Formation appear to be due to precipitates on the surface of individual melanosomes.     

New fossil crocodilians from the Middle/Upper Miocene of Tunisia

New crocodilian material from the Beglia Formation (Middle/Upper Miocene) of Tunisia, although fragmentary, is reported. However, due to its fragmentary nature very little can be said about its affinities, and only the genus Euthecodon can be identified with certainty.     

New specimens of the early Eocene bird Vastanavis and the interrelationships of stem group Psittaciformes

We describe new skeletal elements of Vastanavis from the early Eocene Cambay Shale Formation of western India, including a small coracoid that represents an unnamed new species, and comment on the relationships between this avian taxon and the recently described Avolatavis from the early Eocene Green River Formation in North America. Like the previously described ones, the new Vastanavis bones resemble those of the late Eocene Quercypsittidae, thus strengthening psittaciform affinities of the Indian taxon. Vastanavis differs from Avolatavis in the presence of a crista medianoplantaris on the tarsometatarsus and in claw morphology, but a fossil from the early Eocene London Clay, which was previously assigned to Vastanavidae, closely resembles Avolatavis in these features and all other osteological aspects. We show that most branches in a recent phylogeny of stem group Psittaciformes collapse after modification of a single erroneous character scoring for Vastanavis. We further describe a morphologically distinctive distal humerus of a small bird resembling the stem group nyctibiid Paraprefica, which was discovered in the most recent excavation in Vastan Lignite Mine.     

Fossil ectomycorrhizae from the Middle Eocene

Fossil ectomycorrhizae were found recently among permineralized plant remains in the middle Eocene Princeton chert of British Columbia. The ectomycorrhizae are associated with roots of Pinus and have a Hartig net that extends to the endodermis, a pseudoparenchymatous mantle, and contiguous extramatrical hyphae that are simple-septate. The mycorrhizal rootlets lack root hairs and dichotomize repeatedly to form large, coralloid clusters. Reproductive structures are absent. Based on the morphological characteristics, and the identity of the host, the closely related basidiomycete genera Rhizopogon and Suillus are suggested as comparable extant mycorrhizal fungi. These exquisitely preserved specimens represent the first unequivocal occurrence of fossil ectomycorrhizae and demonstrate that such associations were well-established at least 50 million years ago.     

New Lizards from the Middle Eocene Mergen Formation, Mongolian Gobi Desert

New lizard fossils are described from the middle Eocene Mergen Formation, eastern Gobi Desert in Mongolia. Some 30 isolated tooth-bearing jaws represent at least six lizard taxa. These include three new iguanians that are nonchamaeleonid acrodontans; two scincomorphs having uncertain relationships within the group; and one large anguimorph that may represent a platynotan taxon. Discovery of these fossil lizards is important for accumulating nonmammalian vertebrate data, in attempting to understand a major faunal change that took place in relation to the drastic uplifting of the Mongolian Plateau in Palaeogene time.     

New acrodont lizards (Lacertilia) from the Middle Eocene of southern Mongolia

The problematic lizard family Changjiangosauridae, representatives of which inhabited Asia in the Early Paleogene, is discussed. Six new species of this group, including Acrodontopsis robustus gen. et sp. nov., Agamimus gracilis gen. et sp. nov., Graminisaurus interruptus gen. et sp. nov., Khaichinsaurus reshetovi gen. et sp. nov., Lavatisaurus elegans gen. et sp. nov., and Lentisaurus giganteus gen. et sp. nov., from the Middle Eocene of the Khaichin Uul 2 locality (southern Gobi, Mongolia) are described. It is shown that Changjiangosauridae are probably related to the Late Cretaceous Isodontosauridae and recent Uromastycidae; independent development of a number of dental features in different lineages of Acrodonta (Iguania) is corroborated.     

Eocene fossil is earliest evidence of flower-visiting by birds

Birds are important pollinators, but the evolutionary history of ornithophily (bird pollination) is poorly known. Here, we report a skeleton of the avian taxon Pumiliornis from the middle Eocene of Messel in Germany with preserved stomach contents containing numerous pollen grains of an eudicotyledonous angiosperm. The skeletal morphology of Pumiliornis is in agreement with this bird having been a, presumably nectarivorous, flower-visitor. It represents the earliest and first direct fossil evidence of flower-visiting by birds and indicates a minimum age of 47 million years for the origin of bird–flower interactions. As Pumiliornis does not belong to any of the modern groups of flower-visiting birds, the origin of ornithophily in some angiosperm lineages may have predated that of their extant avian pollinators.     

Fossil water striders from the Middle Eocene fossil sites of Eckfeld and Messel,Germany (Hemiptera,Gerromorpha)

Water striders (Hemiptera, Gerromorpha) are a very distinct ecological group specially adapted for life on the water surface. The present paper reports on four species of Gerromorpha from the Middle Eocene fossil sites of Eckfeld and Messel describingLutetiabates eckfeldensis n. gen. et n. sp.,Cylindrobates messelensis n. gen. et n. sp. (both Gerridae), and two nymphs most probably of the genusGerris. The record of two new members of Gerridae from the Paleogene as well as the hitherto known Gerromorpha from fossiliferous resins document a distinctly higher diversity of water striders within die European Paleogene than today. Lastly, comments are made on the fossil history as well as on the palaeobiological and palaeobiogeographical significance of the faunas.     

New Eocene fossil fruits and leaves of Menispermaceae from the central Tibetan Plateau and their biogeographic implications

Menispermaceae are a pantropical and temperate family with an extensive fossil record during the Paleogene period, especially in North America and Europe, but with much less evidence from Asia. The latest fossil evidence indicates a succession of tropical to subtropical flora on the central Tibetan Plateau during the Paleogene. However, the biogeographic histories of these floras are still unresolved. Here, we report on endocarps and leaves of Menispermaceae from the Middle Eocene of Jianglang village, Bangor County, central Tibetan Plateau. The endocarps belong to two genera: Stephania, which is characterized by a horseshoe-shaped endocarp and with one lateral crest ornamented by spiny to rectangular ribs, and a condyle area; and Cissampelos (s.l.), which has two characteristic lateral ridges and a conspicuous external condyle. Associated leaves belong to the genus Menispermites, and are characterized by actinodromous primary venation, brochidodromous secondary veins, entire margins, and the presence of marginal secondary veins. The biogeographic history of Menispermaceae is complex, but evidence from these new fossils indicates an early diversification of the group in Asia, probably in response to the warming climate during the Eocene. The Jianglang flora appears to be part of a boreotropical flora, connecting Asia with North American and European floras during the Middle Eocene. The modern distribution of menispermaceous taxa found in Jianglang, as well as other families represented in the Jianglang flora, show that a tropical to subtropical climate occurred during the Eocene in central Tibet.     

New specimens of the Eocene Messelirrisoridae (Aves: Bucerotes), with comments on the preservation of uropygial gland waxes in fossil birds from Messel and the phylogenetic affinities of Bucerotes

Exceptionally well-preserved new specimens of the Messelirrisoridae (Aves: Bucerotes), which show previously unknown features of the osteology and feathering of these tiny birds, are described from the Middle Eocene of Messel in Germany. Most notably in one of the new specimens the wing and tail feathers are excellently preserved and even show the former color pattern of the tail. A cream-colored substance in some specimens most likely constitutes fossilized uropygial gland waxes. For the first time, the phylogenetic affinities of the Messelirrisoridae are evaluated in a cladistic analysis, based on 122 characters and 34 extant and fossil taxa. The results of this analysis support the earlier hypothesis that Messelirrisoridae are stem lineage Upupiformes, i.e. the sister taxon of the clade including extant hoopoes (Upupidae) and woodhoopoes (Phoeniculidae). The analysis further supports sister group relationship between Bucerotes (Upupiformes + Bucerotidae [hornbills]) and Piciformes (woodpeckers and allies), although it is detailed that one of the recently proposed apomorphies of the clade (Bucerotes + Piciformes) is absent in the Messelirrisoridae.     

New discoveries of fossil primates from the type Torrejonian (Middle Paleocene of New Mexico.

For the first time in almost 30 years, new Middle Paleocene primate specimens have been discovered in the San Juan Basin, New Mexico. They are from the 'Pantolambda zone' in the type area, Arroyo Torrejon, and are referable to Palaechthon woodi and Torrejonia wilsoni. The only other known association of these two species is in the Shotgun Local Fauna from Wyoming.     

New Middle Eocene Nummulites from Kait Bey,Gebel Mokattam,Egypt

Nummulites paucispira and Nummulites kaitbeyi are newly erected from the Upper Building Stone Member (Bartonian) of the Mokattam Formation at Kait Bey, Gebel Mokattam, Greater Cairo, Egypt both belong to Nummulites partschi group. N. paucispira and N. kaitbeyi are different in their ontogenetic growth stages; N. paucispira has a step of coiling from tight to lax, contrary to N. kaitbeyi. The regression line of both species indicates that both are distinct and they belong to different lineages. Detailed investigations of the new species N. paucispira n. sp. and N. kaitbeyi n. sp. of N. partschi group and their ontogenetic growth stages are discussed. This study is of considerable importance for distinguishing paleoecological events of Bartonian stage and for tracing the phylogenetic trends for the entire Tethys basin.     

Non-marine Teredolites from the Middle Eocene of southern England

Middle Eocene, non-marine sediments from southern England contain examples of Teredolites borings in two contrasting palaeoenvironmental settings, viz.: (A) as in situ borings in an allochthonous lignite in an abandoned river channel and (B) as bored logs in cross-bedded fluvial sandstones of probable point-bar origin. The lignite is 0.30 m thick, of which the upper 0.20 m is intensely bored. Rounded pebbles of ?charcoal at its base also show small borings. A log in a fluvial sandstone shows densely-packed. radial club-shaped borings. now filled with sandstone. The wood substrate has subsequently been oxidized away. To our knowledge, this is the first detailed account of Teredolites from an ancient freshwater setting.     

The first reliable record of fossil leatherback sea turtle (Dermochelyidae) in northern Eurasia (Middle Eocene of Ukraine)

Plates of the epithecal bony shell of turtles of the family Dermochelyidae from the Middle Eocene (Lutetian) of the Ak-Kaya locality (Crimea, Ukraine) are described. This material, determined as Dermochelyidae indet., is the first reliable record of fossil dermochelyids in northern Eurasia.