Lagerstatte Research Articles

Volcaniclastic lithostratigraphy and paleoenvironment of the lower Eocene McAbee fossil beds, Kamloops Group, British Columbia, Canada

The lower Eocene McAbee fossil beds (∼53 Ma), in south-central British Columbia, Canada, represent a lacustrine sequence deposited during a time of pervasive regional volcanism. Previous studies on fossil assemblages at the McAbee fossil beds consist of amalgamated collections of plants from several disjunct and stratigraphically unconstrained exposures and horizons, with limited knowledge of the spatio-temporal variation in depositional and taphonomic setting. This study presents a high-resolution lithostratigraphic analysis of the McAbee main site to provide stratigraphic, paleoenvironmental, and taphonomic context to fossil collections. A lithostratigraphic framework was developed for the McAbee main site by correlating tuff marker beds. The sequence was divided into eight lithostratigraphic units on the basis of systematic lithologic trends, a result of varying degrees of volcanic influences. An absence of shallow water indicators, bioturbation, and evidence for fluvio–deltaic influence, and the nonrestricted presence of highly abundant and diverse well-preserved plant fossils indicates a deep water, yet relatively near shore facies, suggesting steep sided lake margins. This taphonomic regime imparts minimal transport- and degradation-induced biases in fossil plant assemblages and suggests plant fossils represent local vegetation growing near the point of deposition. The new lithostratigraphic framework coupled with a refined understanding of depositional setting and taphonomic regime demonstrates the opportunity to document conditions of forest ecology within a dynamic volcanic environment over millennial and multi-millennial time scales.

You can get anything you want from Alice's Restaurant Bed: exceptional preservation and an unusual fossil assemblage from a newly excavated bed (Ediacara Member, Nilpena, South Australia)

We present findings from the newly discovered fossiliferous bed, TB-ARB, from the Ediacara Member exposed at the National Heritage Site, Nilpena Station, west of the Flinders Ranges, South Australia. TB-ARB contains Ediacaran fossils, some of which are rare, remarkably preserved as casts in fine-grained sandstone with little evidence for taphonomic disturbance. Here we demonstrate that, despite extraordinary preservation, ecological metrics from TB-ARB are characteristic of those found on other Ediacara Member beds and that this fossil assemblage is consistent with the previously recognised heterogeneity of the Ediacaran seafloor. This result suggests that limited taphonomic processes identified on more typical beds at Nilpena do not bias our view of Ediacaran paleoecology, but together, these beds present a complete picture of ancient animal communities. Remarkable preservation of rare Andiva ivantsovi allows investigations of morphology, growth and life habit. We identify complex growth in this organism that maximises surface area relative to volume and a morphology consistent with previously unsubstantiated claims for mobility. Features of Andiva indicate that it was likely related to two other extinct Ediacaran flat-lying, modular, mobile taxa, Dickinsonia and Yorgia, suggesting a possible eumetazoan placement for this organism.

Early Cretaceous polar biotas of Victoria, southeastern Australia—an overview of research to date

Poropat, S.F., Martin, S.K., Tosolini, A.-M.P., Wagstaff, B.E, Bean, L.B., Kear, B.P., Vickers-Rich, P. & Rich, T.H., May 2018. Early Cretaceous polar biotas of Victoria, southeastern Australia—an overview of research to date. Alcheringa 42, 158–230. ISSN 0311-5518.Although Cretaceous fossils (coal excluded) from Victoria, Australia, were first reported in the 1850s, it was not until the 1950s that detailed studies of these fossils were undertaken. Numerous fossil localities have been identified in Victoria since the 1960s, including the Koonwarra Fossil Bed (Strzelecki Group) near Leongatha, the Dinosaur Cove and Eric the Red West sites (Otway Group) at Cape Otway, and the Flat Rocks site (Strzelecki Group) near Cape Paterson. Systematic exploration over the past five decades has resulted in the collection of thousands of fossils representing various plants, invertebrates and vertebrates. Some of the best-preserved and most diverse Hauterivian–Barremian floral assemblages in Australia derive from outcrops of the lower Strzelecki Group in the Gippsland Basin. The slightly younger Koonwarra Fossil Bed (Aptian) is a Konservat-Lagerstätte that also preserves abundant plants, including one of the oldest known flowers. In addition, insects, crustaceans (including the only syncaridans known from Australia between the Triassic and the present), arachnids (including Australia’s only known opilione), the stratigraphically youngest xiphosurans from Australia, bryozoans, unionoid molluscs and a rich assemblage of actinopterygian fish are known from the Koonwarra Fossil Bed. The oldest known—and only Mesozoic—fossil feathers from the Australian continent constitute the only evidence for tetrapods at Koonwarra. By contrast, the Barremian–Aptian-aged deposits at the Flat Rocks site, and the Aptian–Albian-aged strata at the Dinosaur Cove and Eric the Red West sites, are all dominated by tetrapod fossils, with actinopterygians and dipnoans relatively rare. Small ornithopod (=basal neornithischian) dinosaurs are numerically common, known from four partial skeletons and a multitude of isolated bones. Aquatic meiolaniform turtles constitute another prominent faunal element, represented by numerous isolated bones and articulated carapaces and plastrons. More than 50 specimens—mostly lower jaws—evince a high diversity of mammals, including monotremes, a multituberculate and several enigmatic ausktribosphenids. Relatively minor components of these fossil assemblages are diverse theropods (including birds), rare ankylosaurs and ceratopsians, pterosaurs, non-marine plesiosaurs and a lepidosaur. In the older strata of the upper Strzelecki Group, temnospondyl amphibians—the youngest known worldwide—are a conspicuous component of the fauna, whereas crocodylomorphs appear to be present only in up-sequence deposits of the Otway Group. Invertebrates are uncommon, although decapod crustaceans and unionoid bivalves have been described. Collectively, the Early Cretaceous biota of Victoria provides insights into a unique Mesozoic high-latitude palaeoenvironment and elucidates both palaeoclimatic and palaeobiogeographic changes throughout more than 25 million years of geological time.Stephen F. Poropat*† [sporopat@swin.edu.au; stephenfporopat@gmail.com], Faculty of Science, Engineering and Technology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Sarah K. Martin*‡ [sarah.martin@dmirs.wa.gov.au; martin.sarahk@gmail.com] Geological Survey of Western Australia, 100 Plain St, East Perth, Western Australia 6004, Australia; Anne-Marie P. Tosolini [a.tosolini@unimelb.edu.au] and Barbara E. Wagstaff [wagstaff@unimelb.edu.au] School of Earth Sciences, The University of Melbourne, Melbourne, Victoria 3010, Australia; Lynne B. Bean [lynne.bean@anu.edu.au] Research School of Earth Sciences, Australian National University, Acton, Canberra, Australian Capital Territory 2001, Australia; Benjamin P. Kear [benjamin.kear@em.uu.se] Museum of Evolution, Uppsala University, Norbyvägen 16, Uppsala SE-752 36, Sweden; Patricia Vickers-Rich§ [prich@swin.edu.au; pat.rich@monash.edu] Faculty of Science, Engineering and Technology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Thomas H. Rich [trich@museum.vic.gov.au] Museum Victoria, PO Box 666, Melbourne, Victoria 3001, Australia. *These authors contributed equally to this work. †Also affiliated with: Australian Age of Dinosaurs Museum of Natural History, Lot 1 Dinosaur Drive, PO Box 408, Winton, Queensland 4735, Australia. ‡Also affiliated with: Earth and Planetary Sciences, Western Australian Museum, Welshpool, Western Australia 6101, Australia. §Also affiliated with: School of Earth, Atmosphere and Environment, Monash University, Melbourne, Victoria 3800, Australia.

Contrasting Effects of Long-Term Fire on Sagebrush Steppe Shrubs Mediated by Topography and Plant Community

The role of fire in restoration of sagebrush plant communities remains controversial mainly because of paucity of information from long-term studies. Here, we examine 15-year post-fire responses of big sagebrush (Artemisia tridentata ssp wyomingensis) and broom snakeweed (Gutierrezia sarothrae), the two most abundant native shrubs at the John Day Fossil Beds National Monument, a protected area in north-central Oregon, USA. Fire effects were studied along gradients of topography and community type through time post-burn. Community types were distinguished as brush, plots dominated by big sagebrush and woodland, plots with a significant presence of Western juniper (Juniperus occidentalis) trees. Fire reduced big sagebrush cover in brush plots up to 100% and in woodland plots up to 86%. Broom snakeweed cover declined by 92% and 73% in brush plots and woodland plots, respectively. Big sagebrush did not show signs of recovery 15 years after burning regardless of topography and community type while broom snakeweed populations were clearly rebounding and prospering beyond pre-burn levels. Our results showed that an area initially dominated by big sagebrush (cover of big sagebrush 10-20%, cover of broom snakeweed 2-4%) dramatically shifted to an area dominated by broom snakeweed (cover of big sagebrush <1%, cover of broom snakeweed 5%) in brush-dominated plots. Our results indicated that brush-dominated plots at lower elevation and southern exposures are the least post-fire resilient. We also observed a declining population of big sagebrush on unburned areas, suggesting the lack of post-fire recovery on burned areas was perhaps a result of low seeding potential by extant populations. Although more years of observation are required, these data indicate that recovery time, the encroachment of opportunistic competing shrubs, and the initial condition of vegetation are essential considerations by land managers when prescribing fire in big sagebrush communities.

A new macroalgal assemblage from the Xiaoshiba Biota (Cambrian Series 2, Stage 3) of southern China

Exquisitely preserved Burgess Shale-type fossils from the Xiaoshiba Lagerstätte in the Cambrian (Series 2) Hongjingshao Formation of southern China provide remarkable perspective on early metazoans but have never been reported with plants. Here we first recognize a new assemblage of highly mineralized macroalgae from this biota. Based on morphological differences, there are three new genera and four new species identified: Doulia rara gen. et sp. nov., Eolaminaria simigladiola sp. nov., Singulariphyca ramosa gen. et sp. nov. and Rugophyca longa gen. et sp. nov. Relative to the other three species, S. ramosa is widely distributed among the beds, which may indicate a dominat species in this community. This new discovery fills part of the long gap in the detailed record of macroalgae between the Chengjiang Biota and the Kaili Biota, representing a localized macroalgal flourish at the end of Cambrian Stage 3. The assemblage that shows morphological characters similar to some macroalgae found in the Precambrian and primitive to those of the Cambrian Stage 5 lays the basis for revealing the evolutionary biology of early macroalgae and understanding the Precambrian-Cambrian transition questions. Taphonomic study of this fossiliferous bed indicates that some well-preserved macroalgae are preserved within their original habitats. Through analyzing the depositional environments of the known Cambrian macroalgae, we suggest that macroalgae tend to be preserved in relatively deep marine environments with less disturbance.

Impressões foliares pleistocenas de Malvaceae na área de abrangência do Aproveitamento Hidroelétrico Jirau, Rondônia, Brasil

Este trabalho tem como objetivo descrever a morfologia foliar e realizar o reconhecimento taxonô- mico de dez impressões foliares de angiospermas coletadas em afloramento da Formação Rio Madeira na área de abrangência do Aproveitamento Hidrelétrico (AHE) Jirau, resgatadas pela equipe do Programa de Investiga- ção, Salvamento e Monitoramento Paleontológico. Devido à preservação e com base na descrição morfológica, os espécimes foram identificados até o nível de gênero. Todos os espécimes mostram caracteres que indicam sua relação com a família Malvaceae, nove deles com o gênero Luehea e um exemplar ao gênero Theobroma. Duas amostras foram retiradas da camada inferior àquela que concentra os fósseis, com o objetivo de realizar datação através do método “Accelerator Mass Spectrometry” (AMS C14). A datação apontou idades entre 15.910 e 14.850 anos calibrados AP. Os dois gêneros registrados são comuns na cobertura florestal atual na região do AHE Jirau, e a sua presença é também confirmada pelos dados palinológicos obtidos para a parte superior da Formação Rio Madeira.

Devonian–Carboniferous brachiopods and biostratigraphic findings from the Kangal Phyllite–Slate Formation (greenschist), Sivas, Turkey

The Kangal Phyllite-Slate Formation forms the basement rocks in Kangal-Çetinkaya-Alacahan-Divriği (Sivas). These late Paleozoic phyllite-slate associations occupy a large area, possibly composed of Early Paleozoic sediments in its lower part. The lower levels (Bakırtepe Metaquartzite Member; 0-500 m) and uppermost levels comprise the Düzce Recrystallized Limestone Member (0-25 m). The lower boundary is invisible and the upper boundary is unconformably overlain by the Kıratgediği Limestone (late Jurassic- early Cretaceous). The studied brachiopod fauna, about 400 specimens, was collected from the 150-m-thick uppermost part of the greenschist sequences in the Kulluk Hill area, Elkondu village, 25 km east of Kangal. Some bryozoans, corals, trilobites, and crinoids were also retrieved. Five fossiliferous levels belonging to the lower, middle, and upper Devonian, and the lower Carboniferous stages were assigned as follows: (1) Pragian-Emsian; (2) Eifelian-Givetian; (3) Fransian-Famennian-Etroeungtian (Strunian); the Devonian- Carboniferus boundary; (4) lower Carboniferus: Tournaisian and Viséan stages, based on the brachiopods; and (5) upper Permian: from Roadian to Capitanian stages, based on the foraminifera and algae in the Düzce recrystallized limestone. This level indicates a sedimentary interruption. All of these fossils and fossiliferous beds were correlated with the type localities and related beds. The Kangal brachiopods are similar to those of Şafaktepe, the Gümüşali Formations (middle and upper Devonian), and the Ziyarettepe Formation (lower Carboniferous) of the eastern Taurides. The brachiopod community is closely affiliated with the Mediterranean, northwest European Faunal Provinces, part of the Transcaucasian Region, and microfossils of the Düzce recrystallized limestone belonging to the Tethyan Region. Brachiopod fauna and lithologic characteristics of the formation suggest that the upper (150 m) greenschist sequences were deposited in an open shelf environment under warm sea conditions in the Late Paleozoic era.

We decide to hang a man and then don’t, and: Settlers II

We decide to hang a man and then don’t, and: Settlers II Lynnell Major Edwards (bio) WE DECIDE TO HANG A MAN AND THEN DON’T Ruin’t by the rain and many articles missing or scattered about the cabin, thus we findour store of provisions on return, and in despair curse the savage and his band for their depredations,what have so defiled our settlements and camps.We assemble a party, prepare to hunt til eve’n but not any distance find the damn Jack, runaway white servant called Sommers, drunk and wearing our wool leggings, our coat, againstno great cold and torn it besides. So did James raise his tomahawk againstthe man and would have cleaved his skull, but we intendto observe justice, so instead resolved to hang the man, satisfied of his offence. Rope slack about his fat neck, white fleshGone grey and slick with his stink, he soils himself, mumbles womanly prayers to that God what brought us through hardship and peril, what heeds our prayers and bestows great rewards on His servants. [End Page 78] But no one of us willing to slip the knot, we leave him there quiveringon the block, command him ask our forgiveness, tell of what great mercyProvidence has sent. [End Page 79] SETTLERS II (Kentucky River, North Fork) Upstream south and east, so windsthis current towards its source,so bends this stream into forks.We choose north, scramble over moss and boulder,fossil bed and shale flintbroken and loose underfoot.No Shawanoe gold at thatmouth, no Canaan foretold.Abode of desolation, wegrow thin and hungry,pitch asubsistence camp, and no one tells howmen die squatting and alone. [End Page 80] Lynnell Major Edwards Lynnell Major Edwards is the author of three full-length collections of poetry, most recently Covet (Red Hen Press) and a chapbook, Kings of the Rock and Roll Hot Shop (Accents Publishing). She is Associate Professor of English at Spalding University where she teaches writing and literature courses. Copyright © 2018 Berea College

The geological record and phylogeny of spider wasps (Hymenoptera: Pompilidae): A revision of fossil species and their phylogenetic placement.

Accurate fossil identification has become increasingly relevant with the widespread use of phylogenetic divergence time estimation methods, which rely on fossil data to determine clade hard-minimum ages. Here we revise, diagnose and illustrate known spider wasp (Hymenoptera: Pompilidae) fossil species and place them within the latest Pompilidae phylogenetic hypothesis. Ceropalites infelix Cockerell, from the Florissant Fossil Beds (Priabonian), is no longer recognized as Pompilidae, but as Aulacidae. Agenioideus saxigenus (Cockerell) comb. nov., Deuteragenia wettweri (Statz) comb. nov., Caputelus scudderi (Cockerell, 1906) comb. nov., Pepsinites avitula (Cockerell, 1941) comb. nov., Pepsinites contentus (Theobald, 1937) comb. nov., Pepsinites florissantensis (Cockerell, 1906) comb. nov., Pepsinites laminarum (Rohwer, 1909) comb. nov., Pepsinites scelerosus (Meunier, 1919) comb. nov., Pepsinites cockerellae (Rohwer, 1909) comb. nov., Pompilinites coquandi (Theobald, 1937) comb. nov., Pompilinites depressus (Statz, 1936) comb. nov., Pompilites incertus (Theobald, 1937) comb. nov., Pompilites induratus (Heer, 1849) comb. nov., Pompilites fasciatus (Theobald, 1937) comb. nov., and Pompilites senex comb. nov. are new combinations. Twenty-three fossil species of spider wasps are now recognized in 13 genera. Four new genera are proposed: Caputelus Waichert & Pitts gen. nov., Pompilites Rodriguez gen. nov., Pompilinites Rodriguez & Waichert gen. nov., and Pepsinites Rodriguez & Waichert gen. nov., of which the three latter are collective-group names for fossils with taxonomic uncertainty. One species of fossil spider wasp is described: Deuteragenia catalunyia Rodriguez, Waichert & Pitts sp. nov., from the Bellver deposits in Catalonia, Spain. Five of the 23 known species can be used to determine hard-minimum age for calibrations of genera stem-groups (Agenioideus, Anoplius, Cryptocheilus, Deuteragenia, Priocnemis). The fossil belonging to the stem-group of the tribe Ageniellini (Chubutholites) is not recommended for calibration because of the high uncertainty in its age and taxonomy. The remaining taxa can be assigned to the lineage comprising Pompilinae + Pepsinae (12 species) or crown-group Pompilidae (four species).

Giant Shape-Shifters.

The article reports that paleontologists found ancient fossil bed of marine organisms, on Mars depicting the footprints of extinct creatures called rangeomorphs.

A new Mississippian tetrapod from Fife, Scotland, and its environmental context

AbstractThe Visean stage of the Mississippian was a time of rapid tetrapod diversification which marks the earliest appearance of temnospondyls, microsaurs and the limbless aïstopods. Tetrapod finds from this stage are very rare and only a dozen sites are known worldwide. Here we announce the discovery of a new Visean site in Fife, Scotland, of Asbian age, and from it describe a new species of the baphetoid Spathicephalus. These specimens represent the oldest known baphetoid by three million years, yet belong to the most specialized members of the clade. Unlike typical baphetoids with large marginal teeth and palatal fangs characteristic of early tetrapods, spathicephalids had very broad flattened heads with a dentition consisting of a large number of small, uniform teeth. Spathicephalids were probably one of the earliest tetrapod groups to use suction feeding on small, aquatic prey. Palynological and sedimentological analysis indicates that the new fossil bed was deposited in a large, stratified, freshwater lake that became increasingly saline.

The Tule Springs local fauna: Rancholabrean vertebrates from the Las Vegas Formation, Nevada

A middle to late Pleistocene sedimentary sequence in the upper Las Vegas Wash, north of Las Vegas, Nevada, has yielded the largest open-site Rancholabrean vertebrate fossil assemblage in the southern Great Basin and Mojave Deserts. Recent paleontologic field studies have led to the discovery of hundreds of fossil localities and specimens, greatly extending the geographic and temporal footprint of original investigations in the early 1960s. The significance of the deposits and their entombed fossils led to the preservation of 22,650 acres of the upper Las Vegas Wash as Tule Springs Fossil Beds National Monument. These discoveries also warrant designation of the assemblage as a local fauna, named for the site of the original paleontologic studies at Tule Springs.The large mammal component of the Tule Springs local fauna is dominated by remains of Mammuthus columbi as well as Camelops hesternus, along with less common remains of Equus (including E. scotti) and Bison. Large carnivorans including Canis dirus, Smilodon fatalis, and Panthera atrox are also recorded. Micromammals, amphibians, lizards, snakes, birds, invertebrates, plant macrofossils, and pollen also occur in the deposits and provide important and complementary paleoenvironmental information. The fauna occurs within the Las Vegas Formation, an extensive and stratigraphically complex sequence of groundwater discharge deposits that represent a mosaic of desert wetland environments. Radiometric and luminescence dating indicates the sequence spans the last ∼570 ka, and records hydrologic changes in a dynamic and temporally congruent response to northern hemispheric abrupt climatic oscillations. The vertebrate fauna occurs in multiple stratigraphic horizons in this sequence, with ages of the fossils spanning from ∼100 to ∼12.5 ka.

Vertebrate paleontology, stratigraphy, and paleohydrology of Tule Springs Fossil Beds National Monument, Nevada (USA)

Tule Springs Fossil Beds National Monument (TUSK) preserves 22,650 acres of the upper Las Vegas Wash in the northern Las Vegas Valley (Nevada, USA). TUSK is home to extensive and stratigraphically complex groundwater discharge (GWD) deposits, called the Las Vegas Formation, which represent springs and desert wetlands that covered much of the valley during the late Quaternary. The GWD deposits record hydrologic changes that occurred here in a dynamic and temporally congruent response to abrupt climatic oscillations over the last ~300 ka (thousands of years). The deposits also entomb the Tule Springs Local Fauna (TSLF), one of the most significant late Pleistocene (Rancholabrean) vertebrate assemblages in the American Southwest. The TSLF is both prolific and diverse, and includes a large mammal assemblage dominated by Mammuthus columbi and Camelops hesternus. Two (and possibly three) distinct species of Equus, two species of Bison, Panthera atrox, Smilodon fatalis, Canis dirus, Megalonyx jeffersonii, and Nothrotheriops shastensis are also present, and newly recognized faunal components include micromammals, amphibians, snakes, and birds. Invertebrates, plant macrofossils, and pollen also occur in the deposits and provide important and complementary paleoenvironmental information. This field compendium highlights the faunal assemblage in the classic stratigraphic sequences of the Las Vegas Formation within TUSK, emphasizes the significant hydrologic changes that occurred in the area during the recent geologic past, and examines the subsequent and repeated effect of rapid climate change on the local desert wetland ecosystem.

Stratigraphy, paleomagnetism, and cosmogenic-isotope burial ages of fossil-bearing strata within Riverbluff Cave, Greene County, Missouri

AbstractRiverbluff Cave, in Greene County, Missouri, is a short single passage between the James River and its direct tributary, Ward Branch. Before stream incision the cave functioned as a spillway/piracy between the two streams during high-discharge events and accumulated a sequence of stratified fluvial sediments within the cave. Five cosmogenic-nuclide burial ages for these sediments range from 0.984 to 0.570 Ma. These ages are consistent with both the stratigraphic order of the samples and the inferred position of the Matuyama/Brunhes paleomagnetic boundary. These ages indicate that sandy channel-facies deposits derived from Ward Branch entrances began to accumulate within the cave as early as 0.984±0.065 Ma. This facies is capped by highly fossiliferous gravel beds dated at 0.658±0.065 Ma, which contain abundant mammoth bones (possibly Mammuthus trogontherii) and other vertebrates. The high concentration implies that this deposit may record some type of mass-mortality event. By 0.570±0.072 Ma, all Ward Branch entrances had been abandoned because of incision, and a laminated red clay derived from backflow from flooding along the James River capped the older channel sediments.

New Specimens ofAnchiornis huxleyi(Theropoda: Paraves) from the Late Jurassic of Northeastern China

ABSTRACT Four new specimens of Anchiornis huxleyi (PKUP V1068, BMNHC PH804, BMNHC PH822, and BMNHC PH823) were recently recovered from the Late Jurassic fossil beds of the Tiaojishan Formation in northeastern China. These new specimens are almost completely preserved with cranial and postcranial skeletons. Morphological features of Anchiornis huxleyi have implications for paravian character evolution and provide insights into the relationships of major paravian lineages. Anchiornis huxleyi shares derived features with avialans, such as a straight nasal process of the premaxilla and the absence of an external mandibular fenestra in lateral view. However, Anchiornis huxleyi lacks several derived deinonychosaurian features, including a laterally exposed splenial and a specialized raptorial pedal digit II. Morphological comparisons strongly suggest Anchiornis is more closely related to avialans than to deinonychosaurians or troodontids. Anchiornis huxleyi exhibits many conservative paravian features, and clos...

A new species of Argyromys (Rodentia, Mammalia) from the Oligocene of the Valley of Lakes (Mongolia): Its importance for palaeobiogeographical homogeneity across Mongolia, China and Kazakhstan.

We describe a new species of Rodentia (Mammalia), Argyromys cicigei sp. nov. from Toglorhoi (fossil bed TGW-A/2a) in Mongolia and Ulantatal (fossil beds UTL 1 and UTL 7) in China. Its tooth morphology differs from the type species Argyromys aralensis from Akespe in Kazakhstan by smaller size and simpler structures. Argyromys has been assigned in different families of Muroidea, such as Tachyoryctoididae and Spalacidae. However, the presence of common characters indicates a closer relationship of Argyromys with the genera of Cricetidae s.l. (subfamilies Eucricetodontinae; Cricetopinae; Cricetodontinae and Gobicricetodontinae among others) from Asia than with the earliest representatives of Spalacidae or the endemic Tachyoryctoididae. Argyromys cicigei sp. nov. possesses a simple anterocone and anteroconid in the upper and lower first molars, respectively, which is characteristic for Cricetidae s.l. It has a flat occlusal surface in worn specimens; weakly-developed posterolophs; an oblique protolophule and metaloph on the upper molars and it lacks a labial anterolophid on the m1. These traits are also typical of the Oligocene genera Aralocricetodon and Plesiodipus, included in the subfamilies Cricetodontinae and Gobicricetodontinae respectively. The cladistic analysis performed here supports this hypothesis. The clade formed by Argyromys species is grouped with other cricetid taxa (s.l). Spalacids, however, form a different clade, as do the tachyoryctoids. Previous authors state that the Aral Formation (Kazakhstan) should be dated to the Oligocene instead of the Miocene, based on the presence of several taxa. The finds of Argyromys in both regions supports the statement that they are closer in age than previously thought. The occurrence of Argyromys in Kazakhstan, Mongolia and China evidences the biogeographic unity of the Central Asian bioprovince during the Oligocene.

Vertebrate paleontology, stratigraphy, and paleohydrology of Tule Springs Fossil Beds National Monument, Nevada (USA)

Tule Springs Fossil Beds National Monument (TUSK) preserves 22,650 acres of the upper Las Vegas Wash in the northern Las Vegas Valley (Nevada, USA). TUSK is home to extensive and stratigraphically complex groundwater discharge (GWD) deposits, called the Las Vegas Formation, which represent springs and desert wetlands that covered much of the valley during the late Quaternary. The GWD deposits record hydrologic changes that occurred here in a dynamic and temporally congruent response to abrupt climatic oscillations over the last ~300 ka (thousands of years). The deposits also entomb the Tule Springs Local Fauna (TSLF), one of the most significant late Pleistocene (Rancholabrean) vertebrate assemblages in the American Southwest. The TSLF is both prolific and diverse, and includes a large mammal assemblage dominated by Mammuthus columbi and Camelops hesternus. Two (and possibly three) distinct species of Equus, two species of Bison, Panthera atrox, Smilodon fatalis, Canis dirus, Megalonyx jeffersonii, and Nothrotheriops shastensis are also present, and newly recognized faunal components include micromammals, amphibians, snakes, and birds. Invertebrates, plant macrofossils, and pollen also occur in the deposits and provide important and complementary paleoenvironmental information. This field compendium highlights the faunal assemblage in the classic stratigraphic sequences of the Las Vegas Formation within TUSK, emphasizes the significant hydrologic changes that occurred in the area during the recent geologic past, and examines the subsequent and repeated effect of rapid climate change on the local desert wetland ecosystem.

Oligocene stratigraphy across the Eocene and Miocene boundaries in the Valley of Lakes (Mongolia)

Cenozoic sediments of the Taatsiin Gol and TaatsiinTsagaan Nuur area are rich in fossils that provide unique evidence of mammal evolution in Mongolia. The strata are intercalated with basalt flows. 40Ar/39Ar data of the basalts frame the time of sediment deposition and mammal evolution and enable a composite age chronology for the studied area. We investigated 20 geological sections and 6 fossil localities of Oligocene and early Miocene deposits from this region. Seventy fossil beds yielded more than 19,000 mammal fossils. This huge collection encompasses 175 mammal species: 50% Rodentia, 13% Eulipotyphla and Didelphomorphia, and 12% Lagomorpha. The remaining 25% of species are distributed among herbivorous and carnivorous large mammals. The representation of lower vertebrates and gastropods is comparatively poor. Several hundred SEM images illustrate the diversity of Marsupialia, Eulipotyphla, and Rodentia dentition and give insight into small mammal evolution in Mongolia during the Oligocene and early Miocene. This dataset, the radiometric ages of basalt I (∼31.5 Ma) and basalt II (∼27 Ma), and the magnetostratigraphic data provide ages of mammal assemblages and time ranges of the Mongolian biozones: letter zone A ranges from ∼33 to ∼31.5 Ma, letter zone B from ∼31.5 to ∼28 Ma, letter zone C from ∼28 to 25.6 Ma, letter zone C1 from 25.6 to 24 Ma, letter zone C1-D from 24 to ∼23 Ma, and letter zone D from ∼23 to ∼21 Ma.

Taphonomic history of a ‘duck-bill’ dinosaur (Dinosauria: Ornithopoda) from the Cerro del Pueblo Formation (Upper Cretaceous, Campanian) Coahuila, Mexico: Preservational and paleoecological implications

The Cerro del Pueblo Formation in the state of Coahuila, Mexico is becoming recognized worldwide due to its abundant and diverse fossil material. While most previous paleontological work from this rock unit has been directed towards taxonomic investigation, this study is directed towards the taphonomy of a “duck-billed” dinosaur (Ornithischia: Hadrosauridae). The hadrosaur skeleton is represented by several skull bones, vertebrae and ribs, a scapula, pubis, and various appendicular elements. The following taphonomic parameters were considered: (1) bone frequency; (2) hydraulic equivalence; (3) degree of bone articulation; (4) abrasion; (5) weathering; (6) breakage; (7) tooth marks; and (8) trampling activities. The low degree of weathering and abrasion suggests that the specimen experienced a short time of subaerial exposure and underwent a short transportation distance before deposition. Burial occurred within a perimarine lagoonal environment. Furthermore, the lack of hydraulic equivalence with the rock matrix, a high degree of disarticulation and a chaotic distribution of the bones in the fossiliferous bed, suggest that it was transported as a “bloated carcass”. The finding of distinct types of tooth marks evidence some sort of predator/scavenging activities on the specimen. Finally, an almost vertical orientation of various bones and the presence of spiral fractures may indicate that these elements were trampled by other animals.

Preserving fossils in the national parks: A history

ABSTRACT The fossil record preserved throughout the National Park Service spans more than a billion years and is documented in at least 267 park units. The discovery, collection, study, and resource management of fossils from localities which are currently within parks sometimes predate the establishment of the National Park Service and many of the parks. Public education and interpretation at parks such as Agate Fossil Beds and Tule Springs Fossil Beds national monuments and many other designated areas include information on the rich history of paleontological field work by notable paleontologists undertaken prior to the areas being preserved as national park areas. Another important historical aspect for several dozen parks involves the conservation efforts undertaken by the public and interest groups to preserve and protect these important fossil localities. The evolution of the science and methodologies in paleontology is reflected in the resource management undertaken by the National Park Service and documented in park resource management records and archives, scientific publications, and agency policy. Today the National Park Service celebrates fossils by coordinating the National Fossil Day partnership which helps to promote the scientific and educational value of fossils.