A new Burgess Shale-type Lagertatte From the Ediacaran NeoProterozoic Mongolia

A new Burgess Shale-type deposit from the Ediacaran of western Mongolia

Authors:

Dornbos et al

Abstract:

Preservation of soft-bodied organisms is exceedingly rare in the fossil record. One way that such fossils are preserved is as carbonaceous compressions in fined-grained marine sedimentary rocks. These deposits of exceptional preservation are known as Burgess Shale-type (BST) deposits. During the Cambrian Period, BST deposits are more common and provide a crucial view of early animal evolution. The earliest definitive fossil evidence for macroscopic animal-grade organisms is found in the preceding Ediacaran Period. BST deposits from the Ediacaran are rarer and lack conclusive evidence for animals. Here we report the discovery of a new Ediacaran BST deposit with exceptional preservation of non-mineralizing macro-organisms in thinly bedded black shale from Zavkhan Province, western Mongolia. This fossil assemblage, here named the Zuun-Arts biota, currently consists of two new species of probable macroscopic multicellular benthic algae. One species, Chinggiskhaania bifurcata n. gen., n. sp., dominates the biota. The other species, Zuunartsphyton delicatum n. gen., n. sp., is known from three specimens. SEM-EDS analysis shows that the fossils are composed of aluminosilicate clay minerals and some carbon, a composition comparable to fossils from the Cambrian Burgess Shale biota. This discovery opens a new window through which to view late Precambrian life.

pop sci link.

Very Complete Hatchling Hadrosaur Saurolophus angustirostris Found From Upper Cretaceous Mongolia

Perinatal Specimens of Saurolophus angustirostris (Dinosauria: Hadrosauridae), from the Upper Cretaceous of Mongolia

Authors:

Dewaele et al

Abstract:

Background

The Late Cretaceous Nemegt Formation, Gobi Desert, Mongolia has already yielded abundant and complete skeletons of the hadrosaur Saurolophus angustirostris, from half-grown to adult individuals.

Methodology/Principal Findings

Herein we describe perinatal specimens of Saurolophus angustirostris, associated with fragmentary eggshell fragments. The skull length of these babies is around 5% that of the largest known S. angustirostris specimens, so these specimens document the earliest development stages of this giant hadrosaur and bridge a large hiatus in our knowledge of the ontogeny of S. angustirostris.

Conclusions/Significance

The studied specimens are likely part of a nest originally located on a riverbank point bar. The perinatal specimens were buried by sediment carried by the river current presumably during the wet summer season. Perinatal bones already displayed diagnostic characters for Saurolophus angustirostris, including premaxillae with a strongly reflected oral margin and upturned premaxillary body in lateral aspect. The absence of a supracranial crest and unfused halves of the cervical neural arches characterize the earliest stages in the ontogeny of S. angustirostris. The eggshell fragments associated with the perinatal individuals can be referred to the Spheroolithus oogenus and closely resemble those found in older formations (e.g. Barun Goyot Fm in Mongolia) or associated with more basal hadrosauroids (Bactrosaurus-Gilmoreosaurus in the Iren Dabasu Fm, Inner Mongolia, China). This observation suggests that the egg microstructure was similar in basal hadrosauroids and more advanced saurolophines.

Competing Interests

One of the authors (FE) is employed by the commercial organization Eldonia. Eldonia provided support in the form of a salary for FE, but did not have any additional role or influence in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and it does not alter the authors’ adherence to all the PLoS ONE policies on sharing data and materials.

Marine Algae Fossils Found From Cryogenian NeoProterozoic Mongolia

FOSSILS OF PUTATIVE MARINE ALGAE FROM THE CRYOGENIAN GLACIAL INTERLUDE OF MONGOLIA

Authors:

Cohen et al

Abstract:

Neoproterozoic carbonate successions provide a new taphonomic window into the diversification of eukaryotes. We report recently discovered macroscopic organic warty sheets (MOWS) in macerates of limestone from the ca. 662–635 Ma Taishir Formation (Tsagaan Olom Group, Mongolia). Sheets are applanate. One surface contains raised ridges and conspicuous, ∼ 100-µm-tall warty protuberances with depressed tops that enclose internal cavities containing cellular structures. The Taishir MOWS may be the remains of unusual bacterial, protistan, or fungal biofilms, or a previously undocumented, extinct taxon. However, multiple lines of evidence including the morphology of warty protuberances and the presence of cellular architecture within protuberances support the interpretation of MOWS as marine algae, perhaps a member of the Rhodophyta. Regardless of their specific taxonomic affiliation, MOWS increase the diversity of biota reported from the Cryogenian glacial interlude and indicate the presence of macroscopic and morphologically complex multicellular organisms in the Cryogenian.

An Upper Jurassic Lagerstätte Found in Mongolia

Upper Jurassic Lagerstätte Shar Teg, southwestern Mongolia

Authors:

Ponomarenko et al

Abstract:

One of the most interesting Mesozoic Lagerstätten, Shar Teg in southwestern Mongolia, is reviewed. The geological structure and oryctocoenoses of Shar Teg are described. Shar Teg is one of the most diverse Jurassic Lagerstätten in terms of fossils represented. Fossils from Shar Teg include aquatic and terrestrial plants, mollusks, crustaceans, insects, fishes, amphibians, reptiles, and mammals. Insects are the most diverse group. To date, a total of 297 species of 161 families and 22 orders have been described or recorded in Shar Teg, making it possible to reconstruct comprehensively the Jurassic biota of the locality. The oryctocoenosis composition is peculiar; it includes only six species described from other localities. The oryctocoenosis appears to link the faunas of eastern Asia, Central Asia, and Europe. A total of 31 new species are described.

Walking Deinocheirus Rendering

Deinocheirus mirificus Resolved to be Another Whackidillosaurus (Giant, Cretaceous Hump/Sailback MegaOmnivore Dinosaur)

Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificus

Authors:

Lee et al

Abstract:

The holotype of Deinocheirus mirificus was collected by the 1965 Polish–Mongolian Palaeontological Expedition at Altan Uul III in the southern Gobi of Mongolia. Because the holotype consists mostly of giant forelimbs (2.4 m in length) with scapulocoracoids , for almost 50 years Deinocheirus has remained one of the most mysterious dinosaurs. The mosaic of ornithomimosaur and non-ornithomimosaur characters in the holotype has made it difficult to resolve the phylogenetic status of Deinocheirus. Here we describe two new specimens of Deinocheirus that were discovered in the Nemegt Formation of Altan Uul IV in 2006 and Bugiin Tsav in 2009. The Bugiin Tsav specimen (MPC-D 100/127) includes a left forelimb clearly identifiable as Deinocheirus and is 6% longer than the holotype. The Altan Uul IV specimen (MPC-D 100/128) is approximately 74% the size of MPC-D 100/127. Cladistic analysis indicates that Deinocheirus is the largest member of the Ornithomimosauria; however, it has many unique skeletal features unknown in other ornithomimosaurs, indicating that Deinocheirus was a heavily built, non-cursorial animal with an elongate snout, a deep jaw, tall neural spines, a pygostyle, a U-shaped furcula, an expanded pelvis for strong muscle attachments, a relatively short hind limb and broad-tipped pedal unguals. Ecomorphological features in the skull, more than a thousand gastroliths, and stomach contents (fish remains) suggest that Deinocheirus was a megaomnivore that lived in mesic environments.

Tsagandelta dashzevegi: a new Carnivorous Deltatheroidan Metatherian From Cenomanian/Campanian Cretaceous Mongolia

A deltatheroidan mammal from the Upper Cretaceous Baynshiree Formation, eastern Mongolia

Authors:

Rougier et al

Abstract:

Deltatheroidans are a specialized group of basal metatherians with a long fossil history and a broad geographic distribution across Asia and North America. The group was among the first Mesozoic mammals known by relatively complete cranial material, recovered from the Gobi Desert by the American Museum expeditions in the 1920s. Deltatheroidans exhibit trends in their dentition towards apparent specializations for carnivory, including strongly developed postmetacrista, pronounced postvallum-prevallid shear, and a reduction of the ultimate molar. While the oldest undisputed deltatheroidans hail from the Early Cretaceous of North America, Upper Cretaceous rocks in central Asia have yielded the best preserved specimens and the bulk of the diversity. Here we describe a new deltatheroidan, Tsagandelta dashzevegi, gen. et sp. nov., from the Upper Cretaceous Baynshiree Formation of eastern Mongolia. This taxon adds to the diversity of the group in central Asia and provides further evidence of uniformity among the Late Cretaceous vertebrate faunas across the Gobi Desert.

Gobiconodon: Two Species of Carnivorous Mammals From Aptian/Albian Cretaceous Mongolia

Gobiconodon (Mammalia) from the Early Cretaceous of Mongolia and Revision of Gobiconodontidae

Authors:

Lopatin et al

Abstract:

There are two species of Gobiconodon in the Early Cretaceous Khoboor locality of Mongolia: G. borissiaki Trofimov, 1978, and G. hoburensis (Trofimov, 1978). The smaller G. hoburensis has i2 half the size of i1, double-rooted dp2, and two generations of molariforms (m1-5 and m1r-4r). In the larger G. borissiaki, i2 is about ¾ size of i1, dp2 is single-rooted, and there are three generations of molariforms (m1-5, m1r-5r, m1rr-2rr). In larger G. ostromi Jenkins and Schaff, 1988, there are three molariforms of the third generation (m1rr-3rr). The anterior lower dentition of Gobiconodon is interpreted as i1-3, c, and dp1-2. The replacement of dp1 by p1 is known only in G. hoburensis. The dp2 is not replaced and may be lost in some specimens (G. hoburensis, G. ostromi) with its alveolus plugged by bone. Gobiconodon includes five valid species: G. borissiaki, G. hoburensis, G. ostromi, G. hopsoni Rougier et al., 2001, and G. zofiae Li et al., 2001 (=G. luoianus Yuan et al., 2009, syn. nov.). The holotype upper maxilla of G. hopsoni is not diagnostic and a new diagnosis for this species is provided based on lower dentitions from the type locality. Repenomamus Li et al., 2001, and Meemannodon Meng et al., 2005, are the only other members of the Gobiconodontidae. The dental formula of Repenomamus is reinterpreted as I1-3, C, P1, M1-5/i1-2, c, p1-2, m1-5 and thus it differs from Gobiconodon by lack of i3 and P2. Meemannodon is different from Gobiconodon by lack of i3 (the upper dentition is unknown). The Early Cretaceous Jeholodens, Yanoconodon, and Liaoconodon are closer to the Gobiconodontidae than to the Amphilestidae by having only two premolars. Liaoconodon with modified anterior dentition is likely the closest relative to the Gobiconodontidae. The Gobiconodontidae is likely the sister taxon for the clade Amphilestidae + Trechnotheria.

Spring Temperatures Reconstructed Between 1701 to 2008 in the Gobi Desert (and implications for climate change)

Reconstruction of spring temperature on the southern edge of the Gobi Desert, Asia, reveals recent climatic warming

Authors:

Chen et al

Abstract:

We have reconstructed the spring (March-June) temperature from 1701 to 2008 for the Changling Mountains, the southern edge of the Gobi Desert, using mean earlywood density data of Pinus tabulaeformis. The reconstruction explains 41.7% of the actual temperature variance during the common period 1959–2008. The temperature reconstruction is representative of temperature conditions over a large area of Central and East Asia, especially in the Gobi Desert. Significant spectral peaks are identified at 2.0-2.8 and 26.9 years. Our temperature reconstruction successfully captured most recent warming and agreed in general with other temperature reconstructions from nearby regions, eastern China and Northern Hemisphere on a decadal timescale. Our reconstructed temperature is significantly correlated with sea surface temperature in the western tropical and northern Pacific Ocean. Preliminary analysis of links between large-scale climatic variation and the temperature reconstruction shows that there is a relationship between extremes in spring temperature and the Asian summer monsoon circulations.

Putin? Ready to Chow Down on Your Can o Worms?

link.

Disc and Star Shaped Microbial Fossils From an Interglacial Maikhanuul/Ma Nantuo Glaciation of Ediacaran NeoProterozoic Mongolia

Fossil microbial colonies in Neoproterozoic interglacial rocks of Western Mongolia

Authors:

Serezhnikova et al

Abstract:

Glaciogenic deposits are widely distributed in the Neoproterozoic successions around the world, but only few of them are associated with occurrences of authentic macroscopic fossils. Problematical circular remains recovered from intertillite beds of the Neoproterozoic Maikhanuul Formation, Zavkhan basin, Western Mongolia may be a new record of biogenic structures in ancient glacial rocks. The Maikhanuul tillites were deposited between 732–777 Ma (the underlying volcanic rocks of the Neoproterozoic Dzabkhan Formation) and 632 ± 14 Ma (the overlying limestones of the Ediacaran — Nemakit–Daldynian Tsagaanolom Formation). The assemblage of microfossils from the Tsagaanolom Formation is comparable to the assemblage known from the 635–551 Ma Doushantuo Formation of South China. The Maikhanuul glacial event may therefore be correlated with the 635 Ma Nantuo glaciation. Morphological, taphonomic, biometric and geochemical observations have allowed us to interpret the problematical circular remains from the Maikhanuul tillites as microbial communities preserved in situ on the floor of an ancient glacial basin. Many discoidal fossils from Precambrian strata have been compared with extant microbial colonies that have a similar external morphology. However, ultrastructure of the hypothetical Precambrian microbial communities has not hitherto been reported. Scanning electron microscopy of the circular remains from the Maikhanuul tillites revealed filamentous and star-shaped microfossils closely resembling modern bacteria. Some filaments and especially the star-shaped grains are considerably enriched in iron (up to 50%) that may be attributed to bacterial activity. Furthermore, the star-shaped microremains can be compared with modern star-shaped bacteria known from freshwater and terrestrial environments. Although the presence of microbial colonies couldn’t be used for global correlation, it does provide information on prokaryotic diversity and ecology as well as on palaeoenvironmental conditions

Embryonic Enantiornithine Bird Fossils From Campanian Cretaceous Mongolia

An embryonic enantiornithine bird and associated eggs from the cretaceous of Mongolia

Authors:

E. N. Kurochkin, S. Chatterjee and K. E. Mikhailov

Abstract:

Enantiornithes is the most speciose clade of Cretaceous birds, but many taxa are known from isolated postcranial skeletons. Two embryonic enantiornithine bird skeletons of Gobipipus reshetovi gen. et sp. nov. from the Upper Cretaceous (Campanian) Barun Goyot Formation of the Gobi Desert in Mongolia provide new insights into the anatomy, radiation, and mode of development of early avialans. In recent times, both enantiornithine and ornithuromorph birds are known from the Barun Goyot Formation as well as from the Djadokhta and Nemegt Formations. The 80-million-year-old Gobipipus skeletons encased within eggshells shows several features characteristic of enantiornithine birds. The wing skeleton and shoulder girdle show morphological features indicating that Gobipipus achieved sophisticated powered flight. Gobipipus reshetovi gen. et sp. nov. is quite distinct from the sympatric enantiornithine species Gobipteryx minuta from the same strata in many anatomical features. Phylogenetic analysis of 26 avialan ingroup taxa based on distribution of 202 characters indicate that Gobipipus is a basal member of enantiornithine birds along with Confuciusornis and shares more characters with ornithuromorphs than previously recognized. The embryonic nature of Gobipipus specimens sheds new light on the developmental history of enantiornithine birds. The well-ossified bones of the fore- and hind limbs, and fusion of many skeletal elements indicate a precocial mode of development in Gobipipus. Apparently Gobipipus hatchlings could walk away from the ground nests as soon as they emerged from their eggs. The asymmetry of egg poles are unique features of Gobipipus eggs (oogenus Gobioolithus) among Cretaceous avialans. The microstructure of the shell in Gobioolithus eggs with the embryos of Gobipipus is typical avian (of ornithoid basic type) and less ratite-like in morphology of the spongy layer than is that in the other possible egg-remains of enantiornitine birds (oofamily Laevisoolithidae).

Working the Nemegt Formation (Maastrichtian Cretaceous) in Mongolia

What to See Anklyosaur Skin?

An ankylosaurid dinosaur from Mongolia with in situ armour and keratinous scale impressions

Authors:

1. Victoria M. Arbour (a)

2. Nicolai L Lech−Hernes (b)

3. Tom E Guldberg (c)

4. Jørn H Hurum (d)

5. Phillip J Currie (a)

Affiliations:

a. Department of Biological Sciences, CW 405 Biological Sciences Building, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9

b. Bayerngas Norge, Postboks 73, N−0216 Oslo, Norway

c. Fossekleiva 9, N−3075 Berger, Norway

d. Natural History Museum (Geology), University of Oslo, Postboks 1172 Blindern, N−0318 Oslo, Norway

Abstract:

A Mongolian ankylosaurid specimen identified as Tarchia gigantea is an articulated skeleton including dorsal ribs, the sacrum, a nearly complete caudal series, and in situ osteoderms. The tail is the longest complete tail of any known ankylosaurid. Remarkably, the specimen is also the first Mongolian ankylosaurid that preserves impressions of the keratinous scales overlying the bony osteoderms. This specimen provides new information on the shape, texture, and arrangement of osteoderms. Large flat, keeled osteoderms are found over the pelvis, and osteoderms along the tail include large keeled osteoderms, elongate osteoderms lacking distinct apices, and medium−sized, oval osteoderms. The specimen differs in some respects from other Tarchia gigantea specimens, including the morphology of the neural spines of the tail club handle and several of the largest osteoderms.

New Psittacosaurus species

The new dinosaur, Psittacosaurus gobiensis, resembled a modern parrot on steroids, but it was likely not a close relative.

"Psittacosaurus discovered the delights of nut eating 110 million years ago, at least 60 million years before the first parrot arrived," lead author a Paul Sereno told Discovery News.

Sereno, a University of Chicago paleontologist, with colleagues Zhao Xijin and Tan Lin analyzed the remains of the parrot-like dinosaur, which was first unearthed in the western Gobi Desert of inner Mongolia back in 1922. The fossils represent the first and most complete dinosaur excavated in that region at the time.

Sereno and his team, whose findings are published in the latest Proceedings of the Royal Society B, not only identified the new species, but they were also able to determine how, and what, it ate.

Analysis of its skull shows it had reinforcements and "enhanced attachment areas for powerful jaw muscles," as today's parrots do around their beaks. These clues, along with visible tooth wear, allowed the scientists to figure out how the dinosaur bit down on its food.

"Parrot-beaked dinosaurs chewed by sliding their lower jaw forward and then drawing it upward and backward against its upper teeth -- very unusual," said Sereno. "The vast majority of reptiles either just clamp the jaws shut or slide them forward and backward to grind."

No time to comment, but I know most of my readers love the paleo stuff. However, I doubt that this was 60 million years old. (oops!)