Campanian–early Eocene cephalopods from Kharga Oasis,Western Desert,Egypt

The Campanian–lower Eocene sedimentary succession in the Kharga Oasis yields rare cephalopods that have so far received little attention. Eight cephalopod species; six nautiloids and two ammonites, are identified in the study area. The nautiloids are referred to five genera in three families. All nautiloid species are recorded from the Paleocene and Eocene rocks, two of which are described as new, as follows: Cimomia kurkurensis nov. sp. and Deltoidonautilus hassani nov. sp. The two ammonite species are Libycoceras ismaelis (von Zittel, 1884) and Baculites ovatus Say, 1820, representing the families Sphenodiscidae and Baculitidae, respectively. Baculites anceps of Quaas (1902, non Lamarck, 1822) from the Maastrichtian of the Western Desert of Egypt is here assigned to Baculites ovatus. The palaeobiogeography of these species is studied in detail.     

Paleobiogeographic implications of the Middle Eocene ostracods from Cairo–Suez district,Egypt

The main targets of this paper are to examine the Middle Eocene ostracod assemblages collected from a succession exposed in the Cairo–Suez district, Egypt and to detect their paleobiogeographical implications. The studied succession is subdivided into two rock units: the Observatory and Qurn formations, in ascending order. The analysis of the ostracod assemblages led to the identification of 18 species, none of which is new. Three local biozones are established, Digmocythere ismaili - Xestoleberis kenawyi Assemblage Zone, Grinioneis moosi - Loxoconcha pseudopunctatella Assemblage Zone and Cativella qurnenis - Soudanella triangulata Assemblage Zone. The multivariate analyses indicate that there are three distinct bioprovinces, one of them represents the North Africa bioprovince, including Egypt, Libya, and Tunisia. The second bioprovince represents the Middle East, including Jordan and Israel. The third represents the West Africa bioprovince, including Senegal, Togo, Ivory Coast and Nigeria. Therefore, this deduction supports a migration of Eocene ostracods along the southern Tethys.     

Eocene plant diversity at Laguna del Hunco and Río Pichileufú, Patagonia, Argentina

The origins of South America's exceptional plant diversity are poorly known from the fossil record. We report on unbiased quantitative collections of fossil floras from Laguna del Hunco (LH) and Río Pichileufú (RP) in Patagonia, Argentina. These sites represent a frost-free humid biome in South American middle latitudes of the globally warm Eocene. At LH, from 4,303 identified specimens, we recognize 186 species of plant organs and 152 species of leaves. Adjusted for sample size, the LH flora is more diverse than comparable Eocene floras known from other continents. The RP flora shares several taxa with LH and appears to be as rich, although sampling is preliminary. The two floras were previously considered coeval. However, (40)Ar/(39)Ar dating of three ash-fall tuff beds in close stratigraphic association with the RP flora indicates an age of 47.46+/-0.05 Ma, 4.5 million years younger than LH, for which one tuff is reanalyzed here as 51.91+/-0.22 Ma. Thus, diverse floral associations in Patagonia evolved by the Eocene, possibly in response to global warming, and were persistent and areally extensive. This suggests extraordinary richness at low latitudes via the latitudinal diversity gradient, corroborated by published palynological data from the Eocene of Colombia.     

Microfacies,sedimentary environment and paleoecology of Paleocene–Eocene deposits in the Zagros Basin,north of Shiraz,southwest Iran

The Jahrum Formation act as reservoir rocks in the Zagros Mountains west of Iran. For the study of this formation, a stratigraphic section of Lapoee which is situated north of Shiraz has been examined. Petrographic and stratigraphic results along with field observations show that the Jahrum Formation consists of cream-grey thin-to-medium-bedded limestone so that at the top of the formation, they are locally changed to dolomite. The Jahrum Formation overlies the Sachun Formation. We also found Nubecularids as paleoecology indicators in middle parts of the Jahrum Formation. The presence of Nubecularids in the Lapoee stratigraphic section (i.e. the Jahrum Formation) indicates a lagoon depositional environment.     

A small, “wader-like” bird from the Early Eocene of Messel (Germany)

A small bird with a shorebird-like beak and a very long hind toe is described from the Early Eocene of Messel in Germany. Vanolimicola longihallucis, gen. et sp. nov. is one of the few candidate species for a “wading bird” from Messel, that is, a bird that may have foraged along the shoreline of the ancient lake. A few features indicate a relationship to charadriiform birds and Jacanidae (jacanas) in particular, but charadriiform affinities are only weakly supported. In the preserved skeletal elements, V. longihallucis also resembles the taxon Songzia from the Early Eocene of China, which is considered to be a representative of the Ralloidea (rails and allies). A potential biogeographic significance of the new Messel fossil is strengthened by similar fossils from the North American Green River Formation.     

New Discoveries of “Opposum-Like” Marsupials from Antarctica (Seymour Island, Medial Eocene)

Five new species of marsupials are described from the middle Eocene La Meseta Formation of Seymour Island, Antarctic Peninsula. Three are derorhynchid didelphimorphians; one species is a prepidolopid polydolopimorphian, and the last is a microbiotheriid australidelphian. Additionally, fragmentary specimens representing an indetermined derorhynchid and a possible marsupial are also described. The prepidolopid and one of the derorhynchids are sufficiently derived as to preclude any close relationship to other members of that family, but the remaining taxa show the closest affinity with species otherwise known only from Itaboraian and older faunas in Patagonia. This differs from the affinity to early Eocene (Casamayoran) taxa shown by the polydolopid marsupials and placental mammals previously known from the La Meseta Formation. The newly described marsupials indicate that the relict La Meseta Fauna is composed of forms that must have dispersed to Antarctica no later than about early late Paleocene, whereas the previously known taxa apparently arrived in the early Eocene. Ecologically, the La Meseta Fauna is composed mostly of small-sized marsupials of likely insectivorous to frugivorous habits and larger-sized placental herbivores. Whereas the ratite bird of the La Meseta Fauna was probably also herbivorous, the phorusrhachoid and falconid birds comprised a large and smaller carnivorous to possibly scavenging component, respectively. Compared to contemporary faunas of Patagonia, the medium- to large-sized marsupial carnivores are lacking in the Antarctic Peninsula. Nevertheless, the La Meseta Fauna is Patagonian in origin and affinity. In conjunction with new faunas of Itaboraian age (early late Paleocene) in Patagonia, the evidence available indicates that from at least Itaboraian time onward the land mammal fauna of Patagonia and northern South America, as well, is a self-contained unit, developing the diversity characteristic of the Paleogene in that continent, including the australidelphian (but South American) microbiotheres. This, in combination with the apparent separation of Australia from Antarctica at ca. 64 Ma, reinforces interpretations that the precursors of the Australian marsupial fauna most likely dispersed from South America to Australia in the late Cretaceous–early Paleocene.     

Eocene–Oligocene paleoecology and the diatom genus Kisseleviella Sheshukova-Poretskaya from the Victoria Land Basin,Antarctica

The Cape Roberts Project (CRP) recovered a composite Eocene to lower Miocene stratigraphic sequence from the Victoria Land Basin, Antarctica, which includes four new species, described herein, of the biostratigraphically useful fossil marine diatom genus Kisseleviella. Specimens of this extinct genus occur predominantly in neritic sediments, which along with the chain-forming nature and morphological similarity to extant benthic genera (e.g. Cymatosira) suggest that Kisseleviella was tychopelagic. The species of Kisseleviella described here appear to be endemic to the Antarctic region with an ecological preference for nearshore environments. The polythermal, subpolar glacial regime invoked for the late Eocene–early Miocene may have acted as a significant driver of speciation events in Antarctic Kisseleviella. Phylogenetic analysis of fossil genera such as Kisseleviella allows the development of a neritic biostratigraphic zonation. New taxa formally proposed are: Kisseleviella tricoronata, Kisseleviella cicatricata, Kisseleviella gaster and Kisseleviella faballiforma.     

A diverse deep‐marine Ichnofauna from the Eocene Tarcau sandstone of the Eastern Carpathians,Romania

The Paleocene to Middle Eocene Tarcau Sandstone at Buzau Valley, eastern Carpathians, Romania, records sedimentation in a turbidite system. These strata contain a diverse and abundant pre‐ and postdepositional ichnofauna consisting of 35 ichnogenera and 54 ichnospecies. The predepositional assemblage is rich in graphoglyptids and ornate grazing trails; simple grazing trails, resting traces, and feeding structures also occur. The predepositional assemblage includes Acan‐thorhaphe, Belorhaphe, Cardioichnus, Circulichnus, Coch‐lichnus, Cosmorhaphe, Desmograpton, Fustiglyphus, Gordia, Helicolithus, Helminthopsis, Helminthorhaphe, Lorenzinia, Megagrapton, Paleodictyon, Paleomeandron, Protopaleodictyon, Scolicia (S. strozzii), Spirorhaphe, Spirophycus, Treptichnus, and Urohelminthoida. The ich‐nodiversity, composition, ethology, and morphologic complexity of the predepositional association are indicative of the Nereites ichnofacies. The postdepositional association essentially consists of dwelling, feeding, and grazing traces, and is represented by Chondrites, Glockerichnus, Halopoa, Nereites, Ophiomorpha, Phycodes, Planolites, Polykampton, Scolicia(S. prisca. S. striata), Taenidium, Thalassinoides, and Zoophycos. Palaeophycus occurs in both assemblages. Allochthonous Teredolites is present in wood fragments, The postdepositional association includes elements of the Skolithos ichnofacies and facies‐crossing forms that are commonly present in deep‐marine deposits, Elements of the Skolithos ichnofacies are present not only in the most proximal parts of the turbidite system, but also in distal parts. The number of predepositional forms greatly exceeds postdepositional ones, reflecting a dominance of K‐selected over r‐selected population strategies in a stable environment. High levels of ichnodiversity in the Tarcau Sandstone are comparable with deep‐sea ichnofaunas from the Polish Carpathians and with other flysch trace‐fossil assemblages of similar age. This abundant and diverse Eocene ichnofauna supports the idea of extremely rich deep‐sea ichnofaunas in the Cenozoic.     

Middle Eocene–late Oligocene climate variability: Calcareous nannofossil response at Kerguelen Plateau,Site 748

A major deterioration in global climate occurred through the Eocene–Oligocene time interval, characterized by long-term cooling in both terrestrial and marine environments. During this long-term cooling trend, however, recent studies have documented several short-lived warming and cooling phases. In order to further investigate high-latitude climate during these events, we developed a high-resolution calcareous nannofossil record from ODP Site 748 Hole B for the interval spanning the late middle Eocene to the late Oligocene (~ 42 to 26 Ma). The primary goals of this study were to construct a detailed biostratigraphic record and to use nannofossil assemblage variations to interpret short-term changes in surface-water temperature and nutrient conditions. The principal nannofossil assemblage variations are identified using a temperate-warm-water taxa index (Twwt), from which three warming and five cooling events are identified within the middle Eocene to the earliest Oligocene interval. Among these climatic trends, the cooling event at ~ 39 Ma (Cooling Event B) is recorded here for the first time. Variations in fine-fraction δ¹⁸O values at Site 748 are associated with changes in the Twwt index, supporting the idea that significant short-term variability in surface-water conditions occurred in the Kerguelen Plateau area during the middle and late Eocene. Furthermore, ODP Site 748 calcareous nannofossil paleoecology confirms the utility of these microfossils for biostratigraphic, paleoclimatic, and paleoceanographic reconstructions at Southern Ocean sites during the Paleogene.     

A new species of the genus Disogmus Förster (Hymenoptera, Proctotrupoidea, Proctotrupidae) from the Eocene Rovno amber

Disogmus rasnitsyni Kolyada & Perkovsky, sp. n. is described from a fossil inclusion of Late Eocene amber (Ukraine). The new species is most similar to Disogmus basalis (Thomson, 1857), in particular, in the shape of the tyloids and the general shortening of the segments of antennae, but distinctly differs from it and the other species of the genus by having tyloids on flagellar segments 2-4 compared to 3-6 and 4-7 in other species.     

A remarkable new ‘gruiform’ bird from the Middle Eocene of Messel (Hessen, Germany)

Salmila robusta n. gen., n. sp. (Aves: ‘Gruiformes’) is described from the Middle Eocene of Messel (Hessen, Germany). The new species is assumed to have had a predominantly terrestrial habit. It shares derived features of the carpometacarpus with the recent Psophiidae and some taxa of the Cariamae. In several features, however, it distinctly differs from other ‘gruiform’ birds (e. g. in the larger proximal end of the humerus and in the shape of the margo caudalis of the sternum). AlthoughSalmila robusta has been tentatively assigned to the Cariamae in this study, its exact systematic position deserves further investigations. The rather short tarsometatarsus of the new species resembles that of the ‘Messel-phorusrhacid’Aenigmavis sapea Peters 1987.     

Tests of the annual hypothesis and temporal calibration of a 6375‐varve fish‐bearing interval,Eocene horsefly beds,British Columbia,Canada

Eocene lake sediments from Horsefly, British Columbia are rich in fossils of the catostomid fish Amyzon aggregatum. Previous studies of this fish in a 700‐year sequence of varves have demonstrated their potential use in studies of fine‐scale temporal variation in taphonomy and morphology. Tests of the annual (varve) hypothesis for the layers, together with reliable temporal calibration, are necessary prerequisites to any such application. In the present study, a longer continuous sequence from this deposit is subjected to additional tests of the annual hypothesis and is temporally calibrated. Tests include spectral analysis of varve thicknesses, scanning electron microscopy and elemental analysis of dark and light laminae, and analysis of within‐couplet distribution of seasonal fossils. Results support the hypothesis that the couplets are true varves.

Some 6375 varves occur in the studied interval. Each varve is composed of a diatom‐dominated summer lamina and a winter lamina richer in clays, pyrite, and gypsum. Occasional turbidites and thin layers of volcanic ash allow counting and identification of individual varves under low‐power magnification. Fish are rare in the upper 2000 varves but abundant and extensively distributed in the lower 4000 varves of the sequence, making these a potentially valuable interval for studies of microstratigraphic variation in morphology and taphonomy.     

Phytolith analysis of Coprinisphaera,unlocking dung beetle behaviour,herbivore diets and palaeoenvironments along the Middle Eocene–Early Miocene of Patagonia

The analysis of the total number of phytoliths, and the absolute frequencies of the different morphotypes, extracted from fossil dung beetle brood balls (Coprinisphaera) from the Middle Eocene–Early Miocene Sarmiento Formation (Patagonia, Argentina), revealed that this trace fossil represents a concentrated locus for phytolith sampling. Particularly, differences found in the total number of phytoliths among parts of that trace fossil and the bearing paleosol, allowed to infer that the infilling represents mostly a sample of the original surrounding soil, whereas in most cases the wall shows a significantly higher number of phytoliths than in the paleosol or infilling. Modern brood balls also revealed that in an environment with high density of grasses, the walls, composed of soil and dung fibres, showed a lower concentration of phytoliths than the soil. In contrast, in other environment with scarce grass coverage, the dung, which had a higher concentration of phytoliths than the soil, added to the wall produced an increase in the number of phytoliths in it. Accordingly, the larger number of phytoliths of the Coprinisphaera wall in comparison with that of the paleosol, would be reflecting the addition of dung fibres to the wall in palaeoenvironments with moderate to poor presence of phytolith-bearing plants. The absence of differences in the total number of phytoliths between the internal and the external layer of the brood ball wall, suggests that the dung fibres would have been uniformly distributed in most of the wall, due to the addition of dung fibres during the brood ball construction by the dung beetle. In contrast, the absence of differences among wall and paleosol or infilling, could be suggesting that no dung fibres were added to construct the wall, that those added had no phytoliths, that the Coprinisphaera involved could had been a brood ball of a necrophagous scarab, or that the soils were richer in phytoltihs than the dung. Those balls that showed evidence of increased numbers of phytoliths in the wall, likely caused by dung fibres added to it, enable the study of diet preferences of the herbivores that produced the dung. Differences found in the phytolith morphotype frequencies among the wall, and the other two samples (infilling and paleosol), allow to infer that some herbivores were more generalists among phytolith-bearing plants feeding on the most abundant grasses and palms, whereas others preferred more rare grasses and dicots.     

Myrtaceae fossil leaves from the Río Turbio Formation (Middle Eocene), Santa Cruz Province,Argentina

Myrtaceae, the gum tree family, is a large angiosperm clade of 5671 species mostly distributed in tropical and subtropical regions of the world. In the southernmost tip of South America (Santa Cruz province) where the fossils analysed in this study come from (Río Turbio Formation), this family is virtually absent and the extant vegetation is largely dominated by deciduous Nothofagus pumilio and Nothofagus antarctica. During the early Paleogene, however, the Myrtaceae were an important element in southern Patagonian floras. Here, we report and describe ten taxa related to the extant genera Eugenia, Myrcia, Psidium, Myrcianthes and possible Eucalyptus and Campomanesia. The presence of a high diversity of Myrtaceae during the Eocene in one of the southernmost regions of the world could be thought as unusual. However, during this period of time (45 Ma), a number of other tropical lineages also reached these high latitudes probably as a consequence a warming climatic trend. In fact, through the Paleocene–Early Eocene interval, climatic conditions were the warmest of the Cenozoic. After this period of time, a progressive decline in temperature forced the migration of megathermal elements towards lower latitudes and, at the same time, led to the expansion of forest dominated by Nothofagus which predominate the region today.     

Macrocranion tupaiodon,an adapisoricid (?) Insectivore from the Eocene of ‘Grube Messel’ (Western Germany)

The anatomical study of several complete skeletons of the Eocene insectivoreMacrocranion tupaiodon from the “Grube Messel” (Western Germany) allows to reconstruct a number of more relevant biological adaptations of this extinct mammal. Its size is to be compared with small squirrels or treeshrews; its limbs are significantly longer, however.Macrocranion is best characterized as an omnivorous, nocturnal forest-floor predator.     

Cyclocarya cf. paliurus （Batal.） Iljinskaja （Juglandaceae） from the Hunchun Formation （Eocene）, Jilin Province, China

The leaflet architecture of Cyclocarya cf. paliurus （Batal.） Iljinskaja from the Hunchun Formation （Middle Eocene） shows similarity to that of modem C. paliurus （Batal.） Iljinskaja and the specimen is the oldest fossil record in Europe and Asia. The distributions of C. cf. paliurus and other fossil records, such as Glyptostrobus, Metasequoia, Nyssa, and Liquidambar, in Hunchun flora show that it would have been a warmer-temperature to subtropical climate in Hunchun District during the Eocene period.     

First fossil record of Discocephalinae (Insecta,Pentatomidae): a new genus from the middle Eocene of Río Pichileufú, Patagonia,Argentina

A new genus and species of Discocephalini, Acanthocephalonotum martinsnetoi gen. n. et sp. n. is described from Río Pichileufú, middle Eocene of Patagonia, Argentina at palaeolatitude ~ 46°S. The new species is the first fossil representative of the Discocephalinae. This taxon is extant in equatorial to subtropical America, and some species reach warm temperate latitudes (Buenos Aires province). The new genus is distinguished from the other genera of Discocephalini by the combination of these characters: interocular width greater than head length; head massive and quadrangular with the anterior margin almost straight; juga touching each other; labrum thick and curved; triangular ante-ocular process extending beyond the eye; broad spine-like antero-lateral process of the pronotum; pronotum explanate and bean shaped; scutellum triangular with a circular tongue reaching the anterior side of abdominal segment 7; and wings well developed with membrane just surpassing end of abdomen.     

A synoptic review of the Eocene (Ypresian) cartilaginous fishes (Chondrichthyes: Holocephali,Elasmobranchii) of the Bolca Konservat-Lagerstätte,Italy

Here, we review and discuss the records and taxonomy of the Ypresian (Eocene) chondrichthyans from the famous Bolca Konservat-Lagerstätte in northeastern Italy. Despite the outstanding diversity and the numerous studies focusing on the actinopterygian faunas from Pesciara and Monte Postale, the current knowledge about the systematics, taxonomy and phylogenetic relationships of the cartilaginous fishes from these Eocene sites remains elusive and largely inadequate. The celebrated Eocene Bolca Lagerstätte has yielded several exquisitely preserved articulated remains of chondrichthyan fishes in which delicate structures and soft tissues are preserved, as well as isolated teeth. The cartilaginous fish assemblage of Bolca comprises at least 17 species-level taxa belonging to 10 families in 6 orders, including selachians (Carcharhiniformes, Lamniformes), batoids (Torpediniformes, Myliobatiformes, Rajiformes) and holocephalans (Chimaeriformes). The occurrence of holocephalans represented by an isolated fin-spine of the chimeroid Ischyodus in the Bolca assemblage is reported here for the first time and represents the first record of chimeroids in the Eocene of Italy and also southern Europe. The Bolca chondrichthyan assemblage is remarkably different from those of other contemporaneous Boreal or Tethyan deposits, suggesting that its taxonomic composition is largely influenced by the palaeoenvironmental context. However, this synoptic review also highlights the importance of detailed revisions of all chondrichthyan remains from the Bolca Konservat-Lagerstätten.     

New Myanmar middle Eocene anthropoids. An Asian origin for catarrhines?

In April 1997, several new lower jaw fragments of the primates Amphipithecus and Pondaungia were discovered in the Eocene Pondaung Formation in Central Myanmar by the Pondaung Fossil Expedition headed by the Office of Strategic Studies. These new fossils, when compared together and to Siamopithecus from the Late Eocene of Peninsular Thailand, show additional characters that testify to their anthropoid status, to their common origin and to their resemblance to some African relatives. In this paper we describe the new data displayed by these new Myanmar fossils, we identify the characters that unite these Southeast Asian primates as anthropoids and we examine the relationships of this Southeast Asian group with its African counterparts.     

A New Marsupial from the Early Eocene Tingamarra Local Fauna of Murgon, Southeastern Queensland: A Prototypical Australian Marsupial?

Djarthia murgonensis, a new genus and species of marsupial from the early Eocene Tingamarra Local Fauna of Murgon in southeastern Queensland, is described on the basis of dental material. The combination of marsupial synapomorphies and symplesiomorphies present in D. murgonensis suggests phylogenetic placement within either Didelphidae or Australidelphia. Tarsal morphology, fundamental to the concepts of Ameridelphia and Australidelphia respectively, is not yet known for this taxon. Consequently, it cannot be assigned to either clade with confidence. If this taxon is australidelphian, it constitutes support for the hypothesis that the common ancestor of the Australian marsupial radiation was didelphoid-like in dental features. Some previous authors have contended that marsupial faunas of South America and Australia are manifestly distinct, excepting for the australidelphian affinity of South American microbiotheres. However, because tarsal anatomy is unknown in some generalized Australian fossil taxa, including D. murgonensis, and character analysis reveals that no synapomorphies of the dentition unequivocally define either Ameridelphia or Australidelphia to the exclusion of the other, we consider this interpretation to be premature. In short, available evidence neither supports nor refutes the argument of distinct South American and Australasian marsupial faunas. A further ramification is the need to reconsider the phylogenetic position of Ankotarinja tirarensis and Keeuna woodburnei. These central Australian fossil taxa might be referred to either Australidelphia or Ameridelphia, and it is recommended that both be treated as Marsupialia incertae sedis until further material comes to light.