VICIOUS MEAT-EATING HUNTER TRACKED TO AFRICA

While evidence of 95-million year old therapods from Africa is quite scare making one think that each fragment would be treated like gold, this was not the case the first evidence of Carcharodontosaurus iguidensis, a newly described dinosaur from the Cenomanian of Nigeria and published in this months issue Journal of Vertebrate Paleontology.

This fellow almost had the misfortune of going extinct twice! Tooth fragments collected by Charles Depéret and J. Savornin in 1927 were misplaced before this meat-eater could ever be described and when additional material was collected in Egypt in the 1930’s it also came to an unfortunate end. Sent to German paleontologists in Munich to describe, the fossils were lost in the rubble as Allied Forces bombed the building in which they were housed during WW II.But the rocky history and luck of Carcharodontosaurus iguidensis improved when paleontologist in residence at National Geographic, Paul Sereno found cranial material on a Moroccan dig in 1996.

:: THE EVIDENCE MOUNTS...

That find combined with material collected the following year in Nigeria were studied by Sereno, along with Steve Brusatte, a paleobiologist at the University of Bristol in England, and Paul Sereno and determined to be a new species, not C. saharicus as originally thought. The massive skull, neck and bone fragments belonged to Carcharodontosaurus iguidensis, one of the largest dinosaurs ever found. Carcharodontosaurus differs from C. saharicus, his smaller Saharan coursin, both in the maxilla and braincase.

Carcharodontosaurus iguidensis walked upright and was a massive beast, weighing in at an impressive 3.2 tons. Extending upwards of 14 meters (44 ft), nearly as long as Tyrannosaurs, alive today they could easily peer through a second story window - a menacing thought as they were well-equipped hunters with sizable teeth.The climate was much warmer when Carcharodontosaurus iguidensis and C. saharicus roamed the Earth and the seas much higher. Beyond geographic distance, the raised sea level may have been what set these therapods apart.
:: SHALLOW SEAS...

Shallow seas separated what is now Morocco and Nigeria and this separation may have prompted the development of the unique characteristics define the two species.. Perhaps more abundant prey and favorable conditions allowed Carcharodontosaurus iguidensis to grow to their huge size while C. saharicus remained a smallish 1.6 meters (5.2 ft). While not a reptile, C. saharicus has been compared with modern Crocodylia, another group who first appeared in the Cretaceous, as they share similar inner ear anatomy and cerebrum size relative to total brain.

Like many therapods prior to the 1930’s, the African species were originally misgrouped into the genus Megalosaurus. Paleontologist Ernst Stromer von Reichenbach corrected this error. After taking a closer look at their anatomy, particularly their dentition, he renamed them Carcharodontosaurus in 1931 citeing their "mainly Carcharodon-like teeth", which were "not recurved, almost bilaterally symmetrical but with convex edges”

The Carcharodontosaurids were a group of gigantic carnivorous carcharodontosaurid dinosaurs that lived 98 to 93 million years ago. Carcharodontosaurus means 'shark lizard', after the shark genus Carcharodon, an apt handle as they were ominous killers with enormous jaws and long, serrated teeth, some as long as eight inches.

References:

Brusatte, S. and Sereno, P.C. (2005). "A new species of Carcharodontosaurus (Dinosauria: Theropoda) from the Cenomanian of Niger and its implications for allosauroid phylogeny." Journal of Vertebrate Paleontology, 25: 40A.

Brusatte, S.L. and Sereno, P.C. (2007). "A new species of Carcharodontosaurus (dinosauria: theropoda) from the Cenomanian of Niger and a revision of the genus." Journal of Vertebrate Paleontology, 27 (4).

Deparet, C. and Savornin, J. (1927). "Sur la decouverte d'une faune de vertebres albiens a Timimoun (Sahara occidental)." Comptes Rendus, Academie du Sciences, Paris, 181: 1108-1111.Larsson, H.C.E. (2001). "Endocranial anatomy of Carcharodontosaurus saharicus (Theropoda: Allosauroidea) and its implications for theropod brain evolution." Pp. 19-33 in D.H.

Tanke & K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Bloomington.Stromer, E. (1931). "Wirbeltiere-Reste der Baharijestufe (unterestes Canoman). Ein Skelett-Rest von Carcharodontosaurus nov. gen." Abhandlungen der Bayerischen Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Abteilung, 9(Neue Folge): 1–23.

KAYAKING LAKE ISAAC

GLOBAL WARMING: THE TROPICAL EOCENE

In 2004, a scientific crew braced the cold and the odds to extract a sediment core from 400m below the seabed of the Arctic Ocean. The core showed that Fifty-five million years ago, deep in the Eocene, the North Pole was ice-free and enjoying tropical temperatures. It also told us that the temperature of the ocean was 20C, instead of the coolish –1.5C we see today… a truth that is hard to imagine with all the hype around global warming.

The bottom end of that core helped explain the fossils found at Eocene sites around British Columbia, species commonly seen in more tropical environments today.

The warmer temperatures seen at McAbee and around the globe were recorded in the core sample and reveal evidence for a global event known at the Palaeocene-Eocene Thermal Maximum. Back in the Eocene, a gigantic emission of greenhouse gases was released into the atmosphere and the global temperature warmed by about 5C.

While the bookends of the geologic time scale slide back and forth a wee bit, the current experts in the geologic community set the limits to be 33.9 +_ 0.1 to 55.8 +_ 0.2 million years ago. The fossil record tells us that this part of British Columbia and much of the Earth was significantly warmer around that time, so warm in fact that we find temperate and tropical plant fossils in areas that now sport plants that prefer much colder climes, or as is the case in the Arctic, snow and ice.

The Okanagan Highlands is an area centred in the Interior of British Columbia, but the term is used in a slightly misleading fashion to describe an arc of Eocene lakebed sites that extend from Smithers in the north, down to the fossil site of Republic Washington. The grouping includes the fossil sites of Driftwood Canyon, Quilchena, Allenby, Tranquille, McAbee, Princeton and Republic. These fossil sites range in time from Early to Middle Eocene, and the fossil they contain give us a snapshot of what was happening in this part of the world because of the varied plant fossils they contain..

While the area around the Interior of British Columbia was affected. McAbee was not as warm as some of the other Middle Eocene sites, a fact inferred by what we see and what is conspicuously missing.

In looking at the plant species, it has been suggested that the area of McAbee had a more temperate climate, slightly cooler and wetter than other Eocene sites to the south at Princeton, British Columbia and Republic and Chuckanut, Washington. Missing are the tropical Sabal (palm), seen at Princeton and the impressive Ensete (banana) and Zamiaceae (cycad) found at Republic and Chuckanut, Washington.

While we are the likely culprits of much of the warming of the Arctic today, natural processes operating in the not too distant past have also resulted in significant temperature fluxuations on a world-wide scale.

COY BOY AT THE DOG PARK: ANGUS