Italian Ichnospecies

Italian researchers have announced the discovery of a new site with fossilized tracks of archosaurs in the Italian Prealps. The imprints were known by locals of the lake Iseo, but only last year an amateur palaeontologist reported the strange imprints on a vertical rock wall to the authorities (and they eventually acted).

The site is dated to the upper Triassic (220Ma) and at least two kinds of ichnospecies were recognized, one of them is Brachychirotherium – the first segnalation of this ichnopecies in the italian triassic sediments. This discovery has important effects on the reconstruction of the paleogeography of the upper Triassic, it also can give clues on the evolution of the land fauna during the transition of the Permian to the Triassic.

In the last 20 years the fossil record of Italian Permo-Mesozoic terrestrial vertebrates has been increased since the discovery of the dinosaurs tracks by Lerici (Liguria, 1988).
However, important footprints sites were already well-known especially in the Permian, both Early and Late. Early Permian tracks in the Orobic Alps (Lombardy) were described for the first time at the end of the XIX century.
Also in the Late Permian foot-prints have been known for more than one century in the Val Gardena area (Dolomites). This ichnofauna, with 6 ichnogenera and 9 ichnospecies, shows a very important diversity as there are large therapsids and pareiasaurs together with smaller primitive diapsids: it may be considered the most advanced tetrapod fauna in the Permian. In some cases, the foot-prints are exceptionally preserved, showing skin and claw details.
An important peculiarity is the discovery of tracks attributed at Gorgonopsids at the site of Bletterbach (South Tyrol), dated at 260-251 Ma, the only discovery of this kind in central Europe.

The permian-triassic succession at the locality “Bletterbach” South Tyrol.

The known pelycosaurs became extinct during the Permian and were succeeded by the therapsids, mammal-like reptiles that evolved from the pelycosaur lineage and rapidly diversified into herbivorous and carnivorous lineages.


Reconstruction of the fauna of the locality “Bletterbach” South Tyrol, 260-251 million years ago. A) Pareiasaurs B) Pelycosaurs C) Gorgonopsids D) indet lizards


Tracks attributed to Gorgonopsids of the locality “Bletterbach”.

Therapsids were small- to medium-sized animals displaying the beginnings of many mammalian features: fewer bones in the skull due the fusion of skull bones; enlargement of the lower jawbone; differentiation of the teeth for various functions such as nipping, tearing, and chewing food; and a more vertical position of the legs for greater flexibility. Furthermore it is though that therapsids were endothermic, or warm-blooded, enabling them to maintain a constant internal body temperature. This characteristic would have allowed them to expand into a variety of of habitats, and indeed the known fossil-bearing localities have a wide latitudinal distribution.
As the Paleozoic Era came to an End, the therapsids constituted about 80 to 96% of the known reptile genera. The mass extinctions that decimated the marine fauna at the close of the Paleozoic had an equally great effect on the terrestrial population – more then two-thirds of all amphibians and reptiles species were extinct. Plants, on the other hand, apparently did not experience as great a turnover as animals.

References:

Museo tridentino di scienze naturali / Naturmuseum Südtirol ed. (2004): Giornate di Paleontologia 2004 21-23.05: Guida all´escursione

Mammoth killing Meteor

A new hypothesis is dealing with the extinction of mammoths – the archaeologist Dough Kennet and his research team of the University of Oregon have now published in the journal Science an article, that claims that 12.900 years old nano-diamonds found in north American sediments shows that an impact of an extraterrestrial body maybe can blamed to have caused the extinction at the end of the Pleistocene (KERR 2008).

A similar idea was presented by some authors of the recent paper during the congress of the AGU in spring 2007 (BECKER 2007), and a short discussion about the topic was published in Science also in 2007 (KERR 2007).

The institutions of Richard Firestone and the Lawrence Berkeley National Laboratory reported that they had discovered in a peaty stratum iridium iron particles and “bucky balls” (a carbon-modification produced by high temperature and pressure), signs for an impact of an extraterrestrial body (FIRESTONE et al. 2007). But no crater or shocked quartz (produced by the shock waves from the impact) was found, so the researches guessed that the asteroid exploded in the atmosphere, presumably over the icecaps of Greenland. An ulterior "confirm" came from the fossil bones of 10.000 years old mammoth and bison remains. On the bones were found small holes (2-3mm) with burnt zones, containing iron and nickel-rich particles with an unusual isotopic composition (BECKER 2007; KERR 2007).
The extraterrestrial-body-impact is blamed to have caused the extinction of the Pleistocene megafauna by “burning” it down, and furthermore, the resulted melting ice caps of Greenland should have caused an arrestment or a slowdown of the Gulf Stream, causing a 1.500 years long cooling in Europe, the so called Younger Dryas.

The hypothesis is disputable – some points are not yet clear, like the missing crater or other signs of an impact. The hypothetical meteoroid must been large enough to trigger the extinction, but then it seem unlikely that so a large body vaporized or exploded simply in the atmosphere. The interpretation of the particles as nano-diamonds is also debated, the patterns resulted from the analysis with the electron diffraction method is not unique for diamonds.
Also, C14-dated fossils of Pleistocene mammals shows no distinct pattern or a suddenly extinction events like the asteroid scenario requires (LEVY 2006).
And finally the influence of melt water on the transport mechanism of the Gulf Stream is highly debated; it seems improbable that an import of freshwater has so a strong influence on this marine current (CUNNINGHAM et al. 2007).

References:

BECKER (2007): Abstract: The End Pleistocene Extinction Event - What Caused It? Eos Trans. AGU, Abstract PP41A-03

BECKER (2007): Ice Age Impact. mp3 (4MB) (by the Canadian Broadcast)

CUNNINGHAM et al. (2007): Temporal Variability of the Atlantic Meridional Overturning Circulation at 26,5°N. Science Vol.317: 935-938

FIRESTONE et al. (2007): Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. PNAS 105(52)

KERR, R.A. (2007): Mammoth-Killer Impact Gets Mixed Reception From Earth Scientists. Science 316: 1264-1265
KERR, A.R. (2008): PLANETARY IMPACTS: Did the Mammoth Slayer Leave a Diamond Calling Card? Science Vol.323 : 26

LEVY, S. (2006): Clashing with Titans. BioScience Vol. 56(4) : 292-298

The first cheetah

The cheetah lineage is a group of large, slender, and long-limbed cats with a distinctive skull and dental morphology, of which only the extant cheetah (Acinonyx jubatus) is present today. The lineage is characterized by having abbreviated, tall, and domed crania, and a trenchant dentition with a much reduced, posteriorly placed protocone on the upper carnassial. In this article, we report on a new discovery of a Late Pliocene specimen from China with an estimated age of ≈2.2–2.5 million years, making it one of the oldest specimens known to date. A cladistic analysis confirmed that it is the most primitive cheetah known, and it shares a number of unambiguous derived cranial traits with the Acinonyx lineage, but has more primitive dentition than previously known cheetahs, demonstrating that the many unusual skull and dental characters hitherto considered characteristic of cheetahs evolved in a gradual fashion. Isolated teeth of primitive cheetahs may not be recognizable as such, but can be confused with, for instance, those of leopards or other similar-sized pantherine cats or pumas. The age and morphology of the new specimen supports an Old World origin of the cheetah lineage, not a New World one, as has been suggested. We name the new species Acinonyx kurteni in honor of the late Björn Kurtén. (finnish vertebrate paleontologist 1924 -1988).

Skull of modern female cheetah (Acinonyx jubatus)

CHRISTIANSEN, P. & MAZAK, J.H. (2009): A primitive Late Pliocene cheetah, and evolution of the cheetah lineage. PNAS

New PaleomammalsPublications

pdf versions of the cited articles are aviable online:

GOILLOT, C.; BLONDEL, C. & PEIGNE, S. (2009): Relationships between dental microwear and diet in Carnivora (Mammalia) — Implications for the reconstruction of the diet of extinct taxa. Palaeogeography, Palaeoclimatology, Palaeoecology. Vol. 271 (1-2): 1-184

Food consumption causes distinct microwear patterns on teeth, especially in mammals that actively masticate food. Here we perform a microwear analysis to assess the relationships between diet and microwear features of diverse Carnivora. Our database includes approximately 230 individuals of 17 extant species having different diets. We analyse both slicing and grinding facets of M1 and m1. The proposed method is reproducible and allows the differentiation, especially on slicing facets, of microwear poles that are significantly distinct from one another. In carnivorans, the microwear features mainly result from their foraging behavior and the proportion of certain food items consumed. We applied our method to extinct taxa such as the amphicyonid Amphicyon major. The results on the m1 slicing facet indicate dietary similarities between this large Miocene predator and the extant red fox; results from the m1 grinding facet do not have equivalent in extant taxa, however.


FERANEC, R.S.; HADLY, A.E. & PAYTAN, A. (2009): Stable isotopes reveal seasonal competition for resources between late Pleistocene bison (Bison) and horse (Equus) from Rancho La Brea, southern California. Palaeogeography, Palaeoclimatology, Palaeoecology. Vol. 271 (1-2): 153-160

Determining how organisms partition or compete for resources within ecosystems can reveal how communities are assembled. The Late Pleistocene deposits at Rancho La Brea are exceptionally diverse in large mammalian carnivores and herbivores, and afford a unique opportunity to study resource use and partitioning among these megafauna. Resource use was examined in bison and horses by serially sampling the stable carbon and oxygen isotope values found within tooth enamel of individual teeth of seven bison and five horses. Oxygen isotope results for both species reveal a pattern of seasonal enamel growth, while carbon isotope values reveal a more subtle seasonal pattern of dietary preferences. Both species ate a diet dominated by C3 plants, but bison regularly incorporated C4 plants into their diets, while horses ate C4 plants only occasionally. Bison had greater total variation in carbon isotope values than did horses implying migration away from Rancho La Brea. Bison appear to incorporate more C4 plants into their diets during winter, which corresponds to previous studies suggesting that Rancho La Brea, primarily surrounded by C3 plants, was used by bison only during late spring. The examination of intra-tooth isotopic variation which reveals intra-seasonal resource use among bison and horse at Rancho La Brea highlights the utility of isotopic techniques for understanding the intricacies of ecology within and between ancient mammals.

The Tasmanian Wolf lives! (...at least in part)

Australian zoologist have successfully inserted DNA of the since 1936 (assumed) extinct Tasmanian Wolf (Thylacinus cynocephalus) in mouse (Mus musculus) embryos. The inserted genes are" still working" and control the development of cartilagenous and bones .

PASK et al. (2008): Resurrection of DNA Function In Vivo from an Extinct Genome. PLoS ONE 3(5): e2240.

Meet the mighty mammoth

Trying to find something to post about "Meeting a prehistoric creature" for the 20#Boneyard, I was wondering, where can we today meet a animal that no longer exist?

Most animals during earth history became extinct, and with them the ecosystems, that they roamed, are going forever. Maybe, but even in our daily wor(k)ld sometimes we can get a glimps on a prehistoric beast - for example simply by trying to send a letter. The first rappresentation on a stamp from a prehistoric mammal appared in Cuba in 1958, in memory of the centenary of the birth of the naturalist Carlos de la Torre de la Huerta. The stamp showed a giant ground sloth of the genus Megalocnus. Today prehistoric beasts are quiet a common and beautiful motif for a stamp.

A very prominent Behemoth in the collectiv imagination is surely the wolly mammoth (Mammuthus primigenius). Some authors even claim that the name derived from the arabian word "mehemot", and passed trough the jewish "behemoth" until the verses of Job. The Mammoth is also a rare example of extinct animals that possess lots of generic names - the siberian indigenous claimed it "cheli", "uukyla" or "maimant", and interpreted it as a giant rat or mole, guardian of the land of the underground or deads.

We know very much about this animal, not only by fossils or mumificated bodys, found in the siberian permafrost, but we even have the opportunity to observe ancient (10-12.000 B.C.) pictures of it, like in the cave of Rouffignac, in the district Dordogne (Central-France) - and the displayed animals look much better and realistic than a certain recent movie.

What´s the meaning of this art we ignore (and I´m not talking about the movie), but seeing it, we remain affascinated of the naturalistic rappresentation of the animals in display. During the romanian and greek civilitation, and later until the medieval times, the fossils of this prehistoric elephant played an important role in myths and legends of remains from giants and dragons, found in the quaternary deposits of Europe.

Even the first "scientific" reconstruction of an presumed extinct animals shows, at least in part, a mammoth. In 1663 the german naturalist Otto Von Guericke tried to reconstruct the "unicornum verum", the true unicorn, from parts of various pleistocene mammals - the teeths remarkably seems to be the big, striped molars of a Mammoth, even if the skull and the rest of the skeleton is probabily from a wolly rhinoceros. This historic picture is rappresentet in nearby every book about history of the paleontological disciplines.

The true nature of this bones were recongnised in the year 1799, when the Mammoth got´s his scientific name.

Today, every greater Museum for Natural History has or tries to display a Mammoth-skeleton, or at least the typical molar (the picture shows a fossil found in a gravelpit from South Germany) of this animal, in fact, no true museum can be without a trophy of the mighty Mammoth, so the Museum for Natural History in Prague, even if it´s seem they have taken the word "trophy" much to serious.

As a private collector, you can buy not only a complete skeleton, but even mumified skin or fur. So you can claim to possess a carpet from true Mammoth - if you can get the special offer and pay 8.500 Dollars - so last year on the fossil exhibition of Munich! Much of this fossil material is coming in the last years from the russian, and especially siberian territory, from the melting permafrost are emerging tons and tons of fossil bones.

But enough of classic fossils, more cheap, and more cute are surely two merchandising Mammoths in love, or rappresent this picture two males involved in a furious combat? Probabily not, because driving in a car with figthing Mammoths on board can be to dangerous, and so taking photos of them would be difficult, and I would not succeed to take this rare document of ethological behavior.

Anyway, you can inconter the mammoth in todays world in various places (ecosystems?) and different situations, not only in books, but even guarding books...

...on plastic bags (in honor of one of the most complete and biggest skeleton of a Mammoth in Central Europa)...

...or more classic, on a T-shirt...

So, you see, it is not hard to meet prehistoric beast, but to avoid it...

Mammals Blogosphere

The Boneyard XIX is on air, and hostet by Nick Gardner on his brandnew BLOG Familiarity Breeds Content he offers us also some mammal-related news and thoughts.
Searchers after horror haunt strange, far places (H. P. Lovecraft) - so it is not surprising that Michele Whisenhunt is following the footsteps of Dimetrodon in the Permian of Texas - terrifing ancestor of the mammals, which had both mammal and reptile characteristics. Going on, Darren Naish, discuss how "grandma" Lucy maked the first, or at least most important, step to bipedal gait, and why we can´t expect to see an elephant using the same kind of locomotion, even it is a dwarf elephant or a modified amphibian. Thanks to Lucy even the painfull "knuckle-walking" is for us a thing of the past (...maybe).
Brian Switek has celebrated Caturdays, presenting the perfect, terrifying predator of the future. And don´t forget the birthday of (the other) Huxley, in this case we are speaking about "Darwin's Bulldog". Just reaching the goal is the second Mammalthon with a clear 1. place, and because today only the best counts, meet and fear the superpredator - Thylacoleo, from Australia.
Last, but not least, to even accomplain the dark side of the mammal in us - here the story of an inusual behavior of a sexually frustrated fur seal, and a new study provided the exact timing when we finally get this nasty dinosaurs out of the way to rule the world !! ... why is that pigeon looking at me?

The next Boneyard will be hosted on Laelaps, 18.05 - so paleomammologist rise and write, rise... and write...