2011 in Paleontology

Fig 1.- A selection of species described in 2011.

It’s time for a retrospective of year 2011 in the paleontological field. Besides the description and discovery of new species, here is my pick of the top stories that marked the year:

150th anniversary of the description of Archaeopteryx

2011 is a fitting anniversary year for Archaeopteryx with the unveiling of the 11th specimen, the ICZN decision to make the London skeleton the new type for the genus (originally based on a single feather). The systematic position of the transitional fossil is still uncertain with two papers challenging its place at the base of the avialian tree while another puts it back on. An attempt has also been made to reconstruct the color of the London holotype feather.

Fig. 2.- Archaeopteryx.

References:
R. Carney, J. Vinther, M. Shawkey, L. d’Alba & J. Ackermann. 2011. Black Feather Color in Archaeopteryx. 2011 Society of Vertebrate Paleontology Annual Meeting Abstracts, p 84.

Michael S. Y. Lee & Trevor H. Worthy. 2011. Likelihood reinstates Archaeopteryx as a primitve bird. Biology letters. Published online before print.

Darren Naish, Gareth Dyke, Andrea Cau, François Escuillié and Pascal Godefroit. 2011. A gigantic bird from the Upper Cretaceous of Central Asia. Biology Letters. Published online before print. Electronic supplementary info.

Xing Xu, Hailu You, Kai Du and Fenglu Han. 2011. An Archaeopteryx-like theropod from China and the origin of Avialae. Nature 475: 465–470.

ICZN. 2011. OPINION 2283 (Case 3390) Archaeopteryx lithographica von Meyer, 1861 (Aves): conservation of usage by designation of a neotype. Bulletin of Zoological Nomenclature 68 (3): 230–233.

Fig 3.- Polycotylus giving live birth.

Plesiosaur viviparity

The discovery of a fossil plesiosaur (Polycotylus) with a well-developed fetus in its womb strongly suggests that these marine reptiles were giving live birth.

Reference: O'Keefe, F.R.; and Chiappe, L.M. 2011. Viviparity and K-selected life history in a Mesozoic marine plesiosaur (Reptilia, Sauropterygia). Science 333 (6044): 870–873.

Fig 4.- Velociraptor captured with an IR camera.

Theropods were nocturnal

The analysis of scleral rings of many extinct taxa suggests that most theropods and some pterosaurs hunted at nights whereas the herbivorous dinosaurs were mostly diurnal.

Reference: Schmitz, L. and  Motani R. 2011. Nocturnality in dinosaurs inferred from scleral ring and orbit morphology. Science 332, 705.

Fig 5.- Microraptor.

Microraptor ate birds

We already knew that the four-winged dromaeosaur Microraptor was eating small mammals but a new gut content study of one specimen of this dinosaur shows that it also fed on birds.

Reference: O’Connor, Zhou & Xu. 2011. Additional specimen of Microraptor provides unique evidence of dinosaurs preying on birds. PNAS.

Fig 6.- Deinonychus.

A new model for Deinonychus predatory behavior

Deinonychus might have use its powerful claws to pinned down its prey in a manner similar to modern day eagles.

References: Fowler, D. W.; Freedman, E. A.; Scannella, J. B.; Kambic, R. E. 2011. The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds. PLoS ONE 6 (12): e28964.

Fig 7.- Eodromaeus.

Eodromaeus murphi, the earliest theropod?

This little critter might be the earliest and most primitive theropod to date, if indeed Eoraptor is reclassified as a basal sauropodomorph.

Reference: R. N. Martinez, P. C. Sereno, O. A. Alcober, C. E. Colombi, P. R. Renne, I. P. Montañez, and B. S. Currie. 2011. A basal dinosaur from the dawn of the dinosaur era in southwestern Pangaea. Science 331(6014):206-210.

Fig 8.- Camarasaurus herd.

Teeth gave proof of Camarasaurus seasonal migration

… and apparently they traveled quite a long distance in search of food. The technique of teeth analysis for isotopic content shows lots of promise for understanding behavior of creatures long gone.

Reference: H. C. Fricke, J.Hencecroth, M.E. Hoerner. 2011. Lowland–upland migration of sauropod dinosaurs during the Late Jurassic epoch. Nature. Advanced online publication.

Fig 9.- Diania.

Diania, the “walking cactus”

The Lower Cambrian Diania cactiformis is the first fossil of lobopod with jointed legs, and therefore a possible missing link to the Arthropods.

Reference:  Jianni Liu, Michael Steiner, Jason A. Dunlop, Helmut Keupp, Degan Shu, Qiang Ou, Jian Han, Zhifei Zhang & Xingliang Zhang. 2011. An armoured Cambrian lobopodian from China with arthropod-like appendages. Nature. 470, 526–530.

Fig 10.- Juramaia.

Juramaia sinensis, the first eutherian

Juramaia from the Middle Jurassic of Liaoning, China, dislodged Eomaia from the Early Cretaceous as the first known placental mammal.

Reference: Z.-X. Luo, C.-X. Yuan, Q.-J. Meng and Q. Ji. 2011. A Jurassic eutherian mammal and divergence of marsupials and placentals. Nature 476:442-445.

Fig 11.- Shastasaurus.

Shastasaurus may have been a suction feeder

The giant ichthyosaurs of the Late Triassic might indeed have been specialized feeder that preyed on squids.

Reference: Sander PM, Chen X, Cheng L, Wang X (2011) Short-Snouted Toothless Ichthyosaur from China Suggests Late Triassic Diversification of Suction Feeding Ichthyosaurs. PLoS ONE 6(5): e19480.

Fig 12.- Cryptolacerta.

Cryptolacerta hassiaca, the most primitive worm lizard

The modern amphisbaenians are burrowing limbless creatures that superficially resemble earthworms, but Cryptolacerta confirm their link to lizards.

Reference: Müller J., Hipsley C.A., Head J.J., Kardjilov N., Hilger A., Wuttke M. & reisz R.R. 2011. Eocene lizard from Germany reveals amphisbaenian origins. Nature 473, 364-367.

Fig 13.- The Triassic Kraken.

The Artsy Kraken

And finally, 2011 was marked by one outrageous claim about giant cephalopods playing with giant ichthyosaur bones.

Happy New Year 2012, Folks!

Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)

Kronosaurus queenslandicus

Fig. 1.- Reconstruction of Kronosaurus queenslandicus chasing a plesiosaur.

The most famous of the pliosaurs before WWD eclipsed it with an oversized Liopleurodon. This large (9-10 meters)  marine reptile lived in the open oceans of Australia during the Aptian-Albian stage of the Early Cretaceous and was hunting large preys such as the long-necked plesiosaurs. It is known from at least three individuals, one being the iconic Harvard skeleton which was reconstructed with too many dorsal vertebrae making Kronosaurus a bit longer than it really was. A second species, named Kronosaurus boyacensis was found in Northern Colombia.

Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)

References:

Hampe O. 1992. Ein großwüchsiger Pliosauride (Reptilia: Plesiosauria) aus der Unterkreide (oberes Aptium) von Kolumbien. Courier Forschungsinstitut Senckenberg 145: 1-32.

Longman H. A. 1924. A new gigantic marine reptile from the Queensland Cretaceous, Kronosaurus queenslandicus new genus and species. Memoirs of the Queensland Museum 8: 26–28.

Aegyptocetus tarfa

The fossil of this early primitive whale was found cut into multiple slabs from a marbleized limestone imported in Italy. Put back together, it reveals an unusual Protocetid whale with a peculiar skull angled more like the Remingtonocetids such as Remingtonocetus and Dalanistes than the other protocetids and the basilosaurids. Bite marks on the ribs indicated that this particular individual was attacked by a large shark. The fossil came from the Gebel Hof Formation (Middle Eocene) of Wadi Tarfa in the Eastern Desert of Egypt.

Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)

Reference:

G. Bianucci and P. D. Gingerich. 2011. Aegyptocetus tarfa, n. gen. et sp. (Mammalia, Cetacea), from the middle Eocene of Egypt: clinorhynchy, olfaction, and hearing in a protocetid whale. Journal of Vertebrate Paleontology 31(6):1173-1188

Spinops sternbergorum

Fig 1.- Life reconstruction of Spinops sternbergorum.

This dinosaur was “rediscovered” within the precinct of the Natural History Museum in London, almost a century after it was excavated in the Dinosaur Park Formation in Alberta, Canada. It was only very recently realized that the long forgotten skull fragments belong to a new species.

Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)

Fig 2.- Detail.

Reference:

Farke, A.A., Ryan, M.J., Barrett, P.M., Tanke, D.H., Braman, D.R., Loewen, M.A., and Graham, M.R. 2011. A new centrosaurine from the Late Cretaceous of Alberta, Canada, and the evolution of parietal ornamentation in horned dinosaurs. Acta Palaeontologica Polonica 56 (4): 691–702.

Abstract: In 1916, a centrosaurine dinosaur bonebed was excavated within the Campanian−aged deposits of what is now Dinosaur Provincial Park, Alberta, Canada. Specimens from this now−lost quarry, including two parietals, a squamosal, a skull missing the frill, and an incomplete dentary, were purchased by The Natural History Museum, London. The material was recently reprepared and identified herein as a previously unknown taxon, Spinops sternbergorum gen. et sp. nov. Based upon the available locality data and paleopalynology, the quarry lies in either the upper part of the Oldman Formation or the lower part of the Dinosaur Park Formation. The facial region of the partial skull is similar to putative mature specimens of Centrosaurus spp. and Styracosaurus albertensis, with short, rounded postorbital horncores and a large, erect nasal horncore. Parietal ornamentation is consistent on both known parietals and is unique among ceratopsids. Bilateral, procurved parietal hooks occupy the P1 (medial−most) position on the dorsal surface of the parietal and are very similar to those seen in Centrosaurus apertus. Epiparietals in the P2 or possibly P3 position (lateral to P1) manifest as extremely elongate, caudally directed spikes, unlike the condition in C. apertus, S. albertensis, or any other “derived” centrosaurine. Cladistic analysis suggests that S. sternbergorum is closely related to Centrosaurus and Styracosaurus. Historically, based upon the condition in Styracosaurus and related centrosaurines, it was assumed that the medial−most elongated spikes on centrosaurine parietals correspond to the P3 epiparietal position. The exception illustrated in the new taxon suggests that homologies of epiparietals among basal centrosaurines (e.g., Albertaceratops and Diabloceratops) and derived centrosaurines (e.g., Styracosaurus and “pachyrhinosaurs”) should be reconsidered. The medially−placed, caudally−directed “P3” process of basal centrosaurines may, in fact, be homologous with P2.

Cuspicephalus scarfi

Fig 1.- Reconstruction of Cuspicephalus scarfi.

In the series of British prehistoric animals, let me this time introduce you to a pterosaur. Cuspicephalus is known from a partial skull unearthed in the Kimmeridge Clay Formation (Late Jurassic) of Dorset. This critter is possibly  related to the Chinese Darwinopterus.

A new monofenestratan pterosaur from the Kimmeridge Clay Formation (Upper Jurassic, Kimmeridgian) of Dorset, England, David M. Martill and Steve Etches, Acta Palaeontologica Polonica (2011)  in press


Abstract: A new specimen of slender skulled monofenestratan pterosaur from the Late Jurassic Kimmeridge Clay Formation of Dorset, UK, is referred to the new genus and species Cuspicephalus scarfi. The dentition and posterior skull morphology suggest affinities with Darwinopterus, but a close relationship cannot be proved. There are also some similarities with the pterodactyloid Germanodactylus cristatus, but the presence of teeth on the distal rostrum excludes it from that genus. Pterosaur remains are rare in the Upper Jurassic of the UK and this specimen represents the first significant cranial remains of a pterosaur from the Kimmeridge Clay Formation, and possibly the first non-pterodactyloid monofenestratan outside China.

Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)

References:

David M. Martill and Steve Etches. 2011. A new monofenestratan pterosaur from the Kimmeridge Clay Formation (Upper Jurassic, Kimmeridgian) of Dorset, England. Acta Palaeontologica Polonica in press.

Thescelosaurus assiniboiensis

Fig 1.- Reconstruction of Thescelosaurus.

Thescelosaurus is one of those dinosaurs, which did not gain much popularity despite the fact that it is today quite well known scientifically. Even the first specimen, excavated in 1891, remained in its shipping crates for years before being briefly described in 1913 receiving the appropriate name of ‘Thescelosaurus neglectus’ (meaning ‘neglected wondrous lizard’).  Several skeletons, some quite complete, of this little ornithopod have been discovered since then in the United States and Canada. The genus received some media attention in year 2000, when one of the specimens from South Dakota named “Willo” was thought to contain a fossilized heart, a claim, which was later, rejected. To the currently recognized two species, T. neglectus and T. garbanii, a third, the smaller T. assiniboiensis, has just been  described out of a specimen from Saskatchewan.

Brown; Caleb M.; Boyd, Clint A.; and Russell, Anthony P. 2011. A new basal ornithopod dinosaur (Frenchman Formation, Saskatchewan, Canada), and implications for late Maastrichtian ornithischian diversity in North America. Zoological Journal of the Linnean Society 163 (4): 1157–1198.

Abstract: A small, articulated basal ornithopod skeleton from the Frenchman Formation (late Maastrichtian) of Saskatchewan (RSM P 1225.1), previously referred to the taxon Thescelosaurus, differs from both recognized species of this taxon (Thescelosaurus neglectus and Thescelosaurus garbanii). The differences are taxonomically informative and we recognize this specimen as the holotype of a new species, Thescelosaurus assiniboiensis sp. nov., diagnosed by the presence of two autapomorphies, and displaying plesiomorphic traits more similar to those of Parksosaurus, than to those of the other Thescelosaurus species. The Frenchman Formation also harbours an intriguing faunal assemblage in which Thescelosaurus represents one of the most abundant dinosaur taxa, and preserves a relatively high proportion of small (putatively juvenile and subadult) specimens of many dinosaur taxa. Further work that increases the faunal sample from this formation, and that permits quantitative comparisons with contemporary formations, will determine whether or not these differences are well supported, and will determine their ultimate palaeobiological significance. Identification of a third species of Thescelosaurus from the late Maastrichtian of North America suggests that this taxon was more diverse than previously recognized, and shows an increase in diversity from the Campanian through the late Maastrichtian, contrasting the trends seen in most other ornithischian clades.


Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)


References:
Brown; Caleb M.; Boyd, Clint A.; and Russell, Anthony P. 2011. A new basal ornithopod dinosaur (Frenchman Formation, Saskatchewan, Canada), and implications for late Maastrichtian ornithischian diversity in North America. Zoological Journal of the Linnean Society 163 (4): 1157–1198.

Aristosuchus pusillus

 Fig 1.- Reconstruction of Aristosuchus.

Continuing the series of British dinosaurs with the compsognathid Aristosuchus… This one is known from fragmentary postcranial remains from the Isle of Wight, dating from the Early Cretaceous Barremian stage, and originally described in 1876 by Sir Richard Owen (as “Poikilopleuron pusillus”). This little dinosaur was probably very similar to the Late Jurassic Compsognathus from Germany and France and measured about 2 meters in length.

 Fig 2.- Reconstruction of Aristosuchus. Detail.

Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)

References:

D. Naish. 2002. The historical taxonomy of the Lower Cretaceous theropods (Dinosauria) Calamospondylus and Aristosuchus from the Isle of Wight. Proceedings of the Geologists' Association 113:153-163.

R. Owen. 1876. Monograph on the fossil Reptilia of the Wealden and Purbeck formations. Supplement no. VII. Crocodilia (Poikilopleuron) and Dinosauria? (Chondrosteosaurus). [Wealden.]. The Palaeontographical Society, London 1876:1-7

H. G. Seeley. 1887. On Aristosuchus pusillus (Owen), being further notes on the fossils described by Sir R. Owen as Poikilopleuron pusillus, Owen. Quarterly Journal of the Geological Society of London 43:221-228