2014 in Paleontology

Here are my picks for the top paleontology stories of year 2014 (not in particular order):

1) Fossilized pigments show mesozoic marine reptiles in their true colors. 

Tylosaurus nepaeolicus

Ref: Lindgren, J., Sjövall, P., Carney, R. M., Uvdal, P., Gren, J. A., Dyke, G., ... & Polcyn, M. J. (2014). Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles. Nature. 506, 484–488.

2) Copulation and internal fertilization have appeared 385 millions years ago in primitive armored fish adding a big step to our understanding of the evolution of sex in our distant ancestors.

Ref: Long, J. A., Mark-Kurik, E., Johanson, Z., Lee, M. S., Young, G. C., Min, Z., ... & Trinajstic, K. (2014). Copulation in antiarch placoderms and the origin of gnathostome internal fertilization. Nature. Published online

3) New fossils of the cambrian chordate Metaspriggina walcotti show that it was an early very primitive fish.

Metaspriggina walcotti

Ref: Morris, S. C., & Caron, J. B. (2014). A primitive fish from the Cambrian of North America. Nature, 512(7515), 419-422.

4) Exceptionally well preserved fossilized eye tissues of a 300 millions years old spiny shark, Acanthodes bridgei, shows it had color vision.

Acanthodes sp.

Ref: Tanaka, G., Parker, A. R., Hasegawa, Y., Siveter, D. J., Yamamoto, R., Miyashita, K., ... & Maeda, H. (2014). Mineralized rods and cones suggest colour vision in a 300 Myr-old fossil fish. Nature Communications, 5, 5920.

5) Spinosaurus was an odd-looking semi-aquatic predator that might have walked on all four.

Ref: Ibrahim, N., Sereno, P. C., Dal Sasso, C., Maganuco, S., Fabbri, M., Martill, D. M., ... & Iurino, D. A. (2014). Semiaquatic adaptations in a giant predatory dinosaur. Science, 345(6204), 1613-1616.

Deinocheirus mirificus

Spinosaurus aegyptiacus

6) Two new fossils of Deinocheirus mirificus solved 44 years old “terror arms” mystery.

Ref: Lee, Y. N., Barsbold, R., Currie, P. J., Kobayashi, Y., Lee, H. J., Godefroit, P., ... & Chinzorig, T. (2014). Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificus. Nature. 515, 257–260.

Dreadnoughtus schrani

7) Dreadnoughtus schrani, one of the largest dinosaurs and the most complete skeleton of a titanosaur to have been discovered to date.

Ref: Lacovara, K. J., Lamanna, M. C., Ibiricu, L. M., Poole, J. C., Schroeter, E. R., Ullmann, P. V., ... & Novas, F. E. (2014). A Gigantic, Exceptionally Complete Titanosaurian Sauropod Dinosaur from Southern Patagonia, Argentina. Scientific reports, 4, 6196.

Kulindadromeus zabaikalicus

8) The discovery of the feathered ornithischian Kulindadromeus zabaikalicus, suggests that the earliest dinosaurs probably also sported feathers.

Ref: Godefroit, P., Sinitsa, S. M., Dhouailly, D., Bolotsky, Y. L., Sizov, A. V., McNamara, M. E., ... & Spagna, P. (2014). A Jurassic ornithischian dinosaur from Siberia with both feathers and scales. Science, 345(6195), 451-455.

Vintana sertichi

9) The discovery of a complete skull of Vintana sertichi shed light on an obscure group of mammals called Gondwanatheres previously reported from teeth and jaw fragments only.

Ref: Krause, D. W., Hoffmann, S., Wible, J. R., Kirk, E. C., Schultz, J. A., von Koenigswald, W., ... & Andriamialison, H. (2014). First cranial remains of a gondwanatherian mammal reveal remarkable mosaicism. Nature, 515(7528), 512-517.

Atopodentatus unicus

10.- Atopodentatus unicus is probably one of the strangest vertebrate fossil ever found.

Ref: Cheng, L., Chen, X. H., Shang, Q. H., & Wu, X. C. (2014). A new marine reptile from the Triassic of China, with a highly specialized feeding adaptation. Naturwissenschaften, 101(3), 251-259.

Semirostrum cerrutii

11.- A fossil porpoise, Semirostrum cerrutii, reveals unique skim feeding habit.

Ref: Racicot, R. A., Deméré, T. A., Beatty, B. L., & Boessenecker, R. W. (2014). Unique Feeding Morphology in a New Prognathous Extinct Porpoise from the Pliocene of California. Current Biology, 24(7), 774-779.

12.- A massive genomic analysis on 44 species of birds representing all extant orders resolves bird tree-of-life and ancestry. Chickens and turkeys, it turns out, were found to be more closer to their dinosaur ancestors than any other birds.

Ref: Jarvis, E. D., Mirarab, S., Aberer, A. J., Li, B., Houde, P., Li, C., ... & Samaniego, J. A. (2014). Whole-genome analyses resolve early branches in the tree of life of modern birds. Science, 346(6215), 1320-1331.

Extraordinary Tanystropheus

Tanystropheus longobardicus reconstructed as a shoreline fish hunter.

With a length approaching 5 meters for the largest specimens, half of which taken up by an extremely elongated neck, Tanystropheus was a truly remarkable creature. The neck was quite rigid being made of only a dozen of elongated cervical vertebrae. The behavioral habit of Tanystropheus has been intensely debated and the exact function of such a neck still constitutes to this day a puzzling enigma. At first, and based on fragmentary and disarticulated remains from Germany, Tanystropheus was thought to be a flying reptile (Nopsca 1923). Later, when more complete and articulated fossils have been discovered in the Alps, it was viewed as a terrestrial lizard-like creature that hunted fish from the shoreline, using its neck to reach out long distances (Peyer, 1931). Still, a later study found that the neck was probably too rigid to be flexed above shoulder level forcing it to an horizontal position, therefore making a fully aquatic lifestyle more probable (Tschanz, 1986). However, it was argued that Tanystropheus’s skeleton does not show any obvious sign of aquatic adaptation and the limbs were ill-suited for paddling, so the question of how this animal could have swam in open water makes the hypothesis problematic. A new specimen from Switzerland with preserved skin and soft tissue impressions  (Renesto, 2005) shows a large amount of fleshy part in the tail which would have acted as an efficient counterweight to the neck making it possible for the animal to moved it up. This last study makes Peyer’s hypothesis of a semi-aquatic animal staying on the shoreline and using its long neck to reach out for fish farther in the water more likely but the debate is certainly far from being closed (Nosotti, 2007).

Tanystropheus belongs to a small group of basal archosauromorphs (the group that contains all archosaurs such as crocs, dinos and birds) called protorosaurs. Some well known members of this group of Late Permian to Late Triassic animals include Protorosaurus speneri from the Late Permian of Germany, the “monkey lizard” Drepanosaurus unguicaudatus and Megalancosaurus preonensis of the Late Triassic of Italy, and Tanystropheus. Several species of Tanystropheus have been described, probably not all valid. The type species, T. conspicuus Meyer, 1855 from the Middle Triassic (Anisian) Upper Muschelkalk of Germany is known from very fragmentary material. The most completely and best known species is T. longobardicus (Bassani, 1886) for which many specimens, some quite complete, adults and juveniles from the Middle Triassic Besano Formation of Italy were found. Specimens from the Monte San Giorgio in Switzerland have been referred to this species, as well as one specimen from the Falang Formation of the Guizhou province of China (Rieppel et al., 2010). The latter confirms the close faunal connection between the western side of the Tethys sea (Europe) and its eastern border (China) during the Middle Triassic period. T. meridensis Wild, 1980  is known from a single incomplete specimen from the Meride Limestome, Monte San Girogio, Switzerland, but this one is probably a junior synonym of T. longobardicus. T. haasi Rieppel, 2001 from the Middle Triassic Muschelkalk of Israel has been described based on cervical vertebrae.

Tanystropheus forms with all its closest long-necked relatives the family Tanystropheidae. These include Amotosaurus rotfeldensis Fraser & Rieppel, 2006 from the Middle Triassic (Upper Buntsandstein) of Germany, the recently described and oldest member of the group, Augustaburiania vatagini Sennikov, 2011  from the Early Triassic of the Don River, Volgograd Region, Russia, Protanystropheus antiquus (Huene, 1905) from the Middle Triassic (Lower Muschelkalk, Gogolin Formation, Anisian) of Poland, Tanytrachelos ahynis Olsen, 1979 from the Late Triassic (Cow Branch Formation, Newark Supergroup) of North Carolina and Virginia , and Dinocephalosaurus orientalis Li, 2003 from the Middle Triassic (Guanling Formation) of the Guizhou province of China. Some authors also include the bizarre Langobardisaurus Renesto, 1994 from the Late Triassic (Zorzino Limestone Formation) of Italy.

References:

Fraser, N., & Rieppel, O. (2006). A new protorosaur (Diapsida) from the Upper Buntsandstein of the Black Forest, Germany. Journal of Vertebrate Paleontology, 26(4), 866–871.

Nosotti, S. (2007). " Tanystropheus Longobardicus"(Reptilia, Protorosauria): Re-interpretations of the Anatomy Based on New Specimens from the Middle Triassic of Besano (Lombardy, Northern Italy). Società Italiana di Scienze Naturali e Museo Civico di Storia Naturale.

Peyer, B. (Ed.). (1931). Die Triasfauna der Tessiner Kalkalpen. 2. Tanystropheus longobardicus Bass. sp. Birkhäuser.

Renesto, S. (2005). A new specimen of Tanystropheus (Reptilia Protorosauria) from the Middle Triassic of Switzerland and the ecology of the genus. Rivista Italiana Di Paleontologia E Stratigrafia, 111(3), 377–394.

Rieppel, O. (2001). A new species of Tanystropheus (Reptilia: Protorosauria) from the Middle Triassic of Makhtesh Ramon, Israel. Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen, 271-287.

Rieppel, O., Jiang, D., & Fraser, N. (2010). Tanystropheus cf. T. longobardicus from the early Late Triassic of Guizhou Province, southwestern China. Journal of Vertebrate Paleontology, 30(July), 1082–1089.

Tschanz, K. (1986). Funktionelle Anatomie der Halswirbelsäule von Tanystropheus Longobardicus (Bassani) aus der Trias (Anis, Ladin) des Monte San Giorgio (Tessin) auf der Basis vergleichend morphologischer Untersuchungen an der Halsmuskulatur rezenter Echsen. na.

Wild, R. (1980). Tanystropheus (Reptilia: Squamata) and its importance for stratigraphy. Mémoires de la Société Géologique de France NS, 139, 201-206.

Meet the Chroniosuchians

Chroniosaurus dongusensis measured about 30 cm in length.

Chroniosuchians form a very obscure group of small, superficially croc-like four-legged animals that lived during the Late Permian period and survived until the Middle and perhaps Late Triassic periods. Most species are from the Late Permian (Late Tatarian regional stage) of Russia, but they are also known from China, Germany and Kyrgyzstan. They were aquatic or semi-aquatic fish-eating predators characterized by a distinct row of interconnected “butterfly-shaped” bony plates or scutes (osteoderms) covering their back and part of their tail, one for each vertebra. They are traditionally subdivided into two families, the more primitive Chroniosuchidae from the Late Permian with one representative in the Triassic and the Bystrowianidae from the Late Permian to the Middle Triassic. The exact affinities of the Chroniosuchians are quite uncertain. They are usually placed among non-amniote  reptiliomorphs but more recent studies make them “stem tetrapods”, so not reptiles and not quite amphibians but something a bit more primitive. The eel-like embolomeres appear to have been their closest relatives.

Madygenerpeton pustulatus from Kyrgyzstan.

Among the Chroniosuchids, Chroniosaurus dongusensis Tverdochlebova, 1972 from the Late Permian of the Orenburg province of Russia is probably the best known species, with fossils from many individuals including one near complete articulated specimen. Chroniosuchus paradoxus Vjuschkov, 1957 also from the Orenburg province but a bit younger, differs in the taller shape of its skull. Madygenerpeton pustulatus Schoch et al., 2010 from the Middle or Late Triassic of Kyrgyzstan appears to be the basalmost member of the group despite its late occurrence. The type specimen is a nearly complete skull showing a broad snout quite different from the two previous species. Jarilinus mirabilis (Vjuschkov, 1957) from the Novgorod province and Uralerpeton  tverdochlebovae Golubev, 1998 from the Vladimir Province were quite large species for the group, the reconstructed skull of the former measuring 20 cm and of the latter some 55 cm. The others three species, Chroniosaurus levis Golubev, 1908, Chroniosuchus lichaveri (Riabinin, 1962) and Suchonica vladimiri Golubev, 1999, all from the Vologda Province of Russia, are only known from fragmentary remains.

Chroniosuchus paradoxus.

The other family, the Bystrowianids, are much less known, their fossil remains consisting mainly on isolated armor scutes. Late permian species include Bystrowiana permira Vjuschkov, 1957 from the Vladimir Province of Russia, Bystrowiana sinica Young, 1979, Dromotectum largum Liu et al., 2014 and Jinyuanitectum flatum Liu et al., 2014, the last three from the Henan Province of China. Early Triassic species are Axitectum vjushkovi Shishkin & Novikov, 1992 from the Novgorod province, Axitectum georgi Novikov & Shishkin, 2000 from the Kirov province, Dromotectum spinosum Novikov & Shishkin, 1996 from the Orenburg Province. Middle Triassic forms are Synesuchus muravjevi Novikov & Shishkin, 2000 from the Komi Republic and Bystrowiella schumanni Witzmann et al., 2008 from Germany.

References:

Buchwitz, M., Foth, C., Kogan, I., & Voigt, S. (2012). On the use of osteoderm features in a phylogenetic approach on the internal relationships of the Chroniosuchia (Tetrapoda: Reptiliomorpha). Palaeontology, 55(3), 623–640.

Golubev, V. K. (1998). Narrow-armored Chroniosuchians from the Late Permian of Eastern Europe. Paleontological Journal, 32(3), 278–287.

Golubev, V. (1998). Revision of the Late Permian chroniosuchians (Amphibia, Anthracosauromorpha) from Eastern Europe. Paleontological Journal, 32(4), 390–401.

Golubev, V. K. (1999). A New Narrow-Armored Chroniosuchian from the Upper Permian of Eastern Europe. Paleontological Journal, 33(2), 166–173.

Klembara, J., Clack, J. a., & Čerňanský, A. (2010). The anatomy of palate of Chroniosaurus dongusensis (Chroniosuchia, Chroniosuchidae) from the Upper Permian of Russia. Palaeontology, 53(5), 1147–1153.

Liu, J., Xu, L., Jia, S.-H., Pu, H.-Y., & Liu, X.-L. (2014). The Jiyuan tetrapod fauna of the Upper Permian of China — 2 . stratigraphy , taxonomical review , and correlation. Vertebrata PalAsiatica, 52(3), 328–339.

Schoch, R., Voigt, S., & Buchwitz, M. (2010). A chroniosuchid from the Triassic of Kyrgyzstan and analysis of chroniosuchian relationships. Zoological Journal of the Linnean Society, 160, 515–530.

Witzmann, F., Schoch, R. R., & Maisch, M. W. (2008). A relict basal tetrapod from Germany: first evidence of a Triassic chroniosuchian outside Russia. Die Naturwissenschaften, 95(1), 67–72.

Dinosaurs of the British Isles: the Book

For those of you who were wondering why I never completed my series on British dinosaurs on paleoexhibit, stopping midway through the theropods, here is the reason: the material has been used as a starting point for a book. Written in collaboration with Doncaster Museum very own paleontologist and good friend, Dean Lomax, the book has just been published by Siri Scientific Press and is available for purchase on Amazon (link from the ad on the left). Prefaced by Dr. Paul Barrett of the Natural History Museum, “Dinosaurs of the British isles” consists of over 400 pages describing in details some 100 species of dinosaurs unearthed for over two centuries in the United Kingdom. It features extensive amount of photographs of fossil remains taken by Dean as he visited all the major paleontology collections from England, Scotland and Wales, skeletal reconstructions from Scott Hartman, Jaime Headden and Greg Paul, as well as life reconstructions by talented artist James McKay, and by myself. Highly recommended to anybody interested in fossils in general, and British dinosaurs in particular.

Reference: D. R. Lomax & N. Tamura, 2014. “Dinosaurs of the British Isles”, Siri Scientific Press, 414 pages, ISBN 13: 9780957453050, ISBN 10: 0957453051

Two late Scottish relatives of Jamoytius

Cornovichthys blaauweni.

The now flooded Achanarras fish beds in Caithness, Northern Scotland, has yielded an abundant collection of fossil fish belonging to some 15 genera dating from the Eifelian stage (about 390 MYA) of the Middle Devonian period. These include the arthrodire (a group of heavily armored jawed fish) Coccosteus cuspidatus, the Acanthodians (“spiny sharks”) Diplacanthus, Mesacanthus and Cheiracanthus, the enigmatic Palaeospondylus gunni, the early Actinopterygian (ray-finned fish) Cheirolepis treilli and the Sarcopterygians (lobed-finned fish) Osteolepis macrolepidotus and Dipterus valenciennesi. The agnathans (jawless fish) are a rarity there and consist of only two species, Cornovichthys blaaweni and Achanarella trewini, which are believed to be closely related to Jamoytius kerwoodi from the Silurian, and placed in the clade Jamoytiiforms. The limestone of Achanarras quarry has been deposited in what appear to have been a deep freshwater lake environment.

Cornovichthys blaauweni is known from a single carbonaceous impression of a complete specimen measuring a little over 10 cm in length. The body is long and slender with a hypocercal tail and a quite large anal fin. There is no evidence of any other fin, nor of any scale in the specimen. Eyes appear to be situated near the top surface of the head. Overall, Cornovichthys looks a lot like Euphanerops and like its Canadian counterpart has a long series of branchial openings running from the head to the anal fin, numbering to around 15 on each side of the body.

Achanarella trewini.

Achanarella trewini is known from many specimens that were found in large numbers on single slabs of rock. Individuals of Achanarella range in size from 2 cm to 9 cm in length. Like Cornovichthys, it has a hypocercal tail and a large anal fin, no apparent scale and a large number of branchial openings on each side of the body, 13 or more, but the body is much thinner and elongated and the head is extremely small. Just like Jamoytius and Euphanerops, Cornovichthys and Achanarella were probably feeding on micro-organisms and detritus through their jawless mouth.

Reference:

Newman, M., & Trewin, N. (2001). A new jawless vertebrate from the Middle Devonian of Scotland. Palaeontology, 44, 43–51.

Newman, M. (2002). A new naked jawless vertebrate from the Middle Devonian of Scotland. Palaeontology, 45(5), 933–941.

The Canadian cousins of Jamoytius

Euphanerops longaevus

The rich Late Devonian fish fauna of Miguasha, in Eastern Quebec, Canada (Escuminac Formation) includes some peculiar jawless fish closely related to the Silurian scottish species Jamoytius kerwoodi. They have a strongly hypocercal tail with a relatively large anal fin. The body is elongated and have a series of long and narrow weakly mineralized scales on the flanks. The eyes are relatively large and the mouth is a circular opening situated at the bottom of the head. Like most if not all primitive fish, they lack paired fins. The branchial openings were numerous numbering 30 or so (lampreys have only 7 of these gill pouches) aligned from the head to the anal region, and therefore stretching over a very long portion of the body. This peculiar arrangement is thought to be an adaptation to a poorly oxygenated water. The first species to be described is Euphanerops longaevus by the British paleontologist Sir Arthur Smith Woodward in 1900. This strange animal was however originally described upside down, with the anal fin as a dorsal one and an epicercal tail. Euphanerops measured about 10 cm in length. The second species is Endeiolepis aneri described by the swedish paleontologist Erik Stensiö in 1939. It is very similar to Euphanerops and it was suggested that the two represent the same animal, with Euphanerops being the juvenile form. In that case, the name Euphanerops has priority and Endeiolepis would be a junior synonym. Legendrelepis parenti described by M. Arsenault and P. Janvier, 1991 is considered to be a junior synonym as well, any noted differences such as the alleged presence of a dorsal fin are now viewed as artifacts of preservation.

References:

Janvier, P., Desbiens, S., Willett, J. a, & Arsenault, M. (2006). Lamprey-like gills in a gnathostome-related Devonian jawless vertebrate. Nature, 440(7088), 1183–5. 

Janvier, P., & Arsenault, M. (2007). The anatomy of Euphanerops longaevus Woodward, 1900, an anaspid-like jawless vertebrate from the Upper Devonian of Miguasha, Quebec, Canada. Geodiversitas, 29(1), 143–216.