Wednesday, October 20, 2010
Finally! A marine reptile gets some time in the spotlight. Shonisaurus is the largest of any marine reptile yet discovered. There are two species within the genus: S. popularis and S. sikanniensis, the latter being the larger of the two at an estimated 69 feet (21 meters) in length. Shonisaurus belongs to the family Shastasauridae within the order Ichthyosauria, and its closest relatives include Besanosaurus and Shastasaurus.
Shonisaurus lived during the Norian stage of the Upper Triassic, and has been found in Nevada, British Columbia, and possibly the Himalayas. It posesses several traits, such as relatively long and thin flippers, which seem to suggest that it does not belong to the main branch of the ichthyosaurian evolutionary tree, and instead belongs to a sort of offshoot from that group.
It posessed several conical teeth which existed only at the front of its mouth, and a rather large body for an ichthyosaur.
Monday, October 18, 2010
It's so beautiful.
The Princeton Field Guide to Dinosaurs is Gregory S. Paul's latest book, and has detailed information on nearly every recognized (and some unrecognized) species of dinosaur, from the tiniest ornithopod to the tyrant kings. Accompanying the book's descriptions are Paul's splendid - as usual - artwork. The book is the most up-to-date dinosaur encyclopedia on the market now, to the best of my knowledge.
The book details the geographic and chronological distribution of the various dinosaurs, the formation they were found in, their habitat, their eating habits, what separates them from their relatives, and other notes. The book is enlightening and scholarly, while simultaneously having the benefit of being accessible to those who are less dino-literate.
I give this book the official SR Seal of Approval, and would recommend it to any lover of dinosaur paleontology in a heartbeat.
In unrelated news, the whole leopard gecko thing kinda fell through. I hope to get one eventually, but for the foreseeable future, I won't be getting one. Need to get the time and money together to buy one.
Meanwhile, in dinosaur-land, a battle is being waged over the fate of Raptorex (shudder), with some alleging that it is yet another juvenile Tarbosaurus (see: Alioramus), and others defending it, on the grounds that a certain ridge on its pelvis distinguishes it from that Asian tyrannosaur.
Personally, I hope Raptorex's name vanishes into the taxonomical trashbin, never to be seen again.
News of supposed Middle Jurassic bird footprints in Africa... Given Africa's scant Mesozoic record, I wouldn't be terribly surprised if this, and other unusual things in the future, may turn out to be true about this paleontological blank spot.
Hopefully, I'll give more updates in the near future and learn to stop slacking off. Wish me luck.
Tuesday, August 31, 2010
Sunday, August 29, 2010
Monday, June 14, 2010
Well, long story short, they described something like six new genera of ceratopsians while I was away, including the first of the horned dinosaurs from Europe, as well as the first true ceratopsid from outside North America, and the biggest horns in any dinosaur. The good stuff always happens while I'm away!
Wednesday, April 7, 2010
Though most famous for its Triassic record, the coelophysids were a greatly successful group, surviving into the Early Jurassic across North America and Africa. They were light-boned, fleet-footed predators, well-suited to a world of small prey which could run just as fast as it could. They are placed within the Theropoda, and are believed to be more primitive than the ceratosaurs and tetanurans.
Coelophysis bauri was first described by Edward Drinker Cope in 1889 from fossils found in the American Southwest, but it's unsure if these fossils even belong to the dinosaur at all. Later bones attributed to Coelophysis definitely belong to a theropod dinosaur, and as such, Coelophysis is still a valid dinosaurian genus.
Coelophysidae is also home to what is, possibly, the worst dinosaur name ever: Megapnosaurus. Once beloved by dinosaur fans as Syntarsus, the entomologists struck again: Syntarsus was taken by a beetle. In some miscarriage of justice, the entomologists who pointed this out now had the right to rename the animal. It is now Megapnosaurus - "big dead reptile". I'm not sure if this shows a twisted sense of humor on the entomologists' parts, or simply ignorance as to the true nature of dinosaurs.
This family posesses seven species across six genera.
Coelophysidae (Nopsca, 1923)
Coelophysis bauri (Cope, 1889)
Megapnosaurus rhodesiensis (Raath, 1969)
Megapnosaurus kayentakatae (Rowe, 1989)
Camposaurus arizonensis (Hunt et al., 1998)
Podokesaurus holyokensis (Talbot, 1911)
Procompsognathus triassicus (Fraas, 1913)
Segisaurus halli (Camp, 1936)
(Sorry for paragraph-fail. I blame the website!)
Friday, April 2, 2010
The type species, Herrerasaurus ischigualastensis, was described by Osvaldo Reig in 1963 in the Ischigualasto Formation of Brazil. The specimen variously jumped around into several different placements, from prosauropods and non-dinosaurian archosaurs, to a primitive carnosaur. Since then, the classification has settled to the two options found in the previous paragraph, and the group is defined as the most inclusive clade containing Herrerasaurus ischigualastensis, but not Passer domesticus.
The family dates to the Late Triassic, from about 228 to 225 million years ago. They are most commonly found in South America (Brazil & Argentina), but specimens are also known from North America (Arizona & Texas). The possibility remains that there could be others found on other continents. The group contains at least three species across at least three genera.
Family Herrerasauridae (Benedetto, 1973)
Herrerasaurus ischigualastensis (Reig, 1963)
Staurikosaurus pricei (Colbert, 1970)
Chindesaurus bryansmalli (Long & Murry, 1995)
Thursday, April 1, 2010
For the benefit of those who view my page, I will go through every major grouping of dinosaurs (the families, but in some cases, subfamilies as well), and offer a summary of that group's features, and a list of species which belong in the group. The segment will begin tomorrow with the most primitive of the dinosaur families, Herrerasauridae.
Wednesday, March 31, 2010
Friday, March 19, 2010
Wednesday, February 24, 2010
Monday, February 22, 2010
If it ends with -us, generally its plural ends with -i. Example: cactus -> cacti. Some other plurals for words, however, end with -era. Example: genus -> genera.
If it ends with -a, its plural ends with -ae. Examples: alumna -> alumnae, aurora -> aurorae.
If it ends in -um, its plural ends with -a. Examples: medium -> media, datum -> data. (Yes, data is plural.)
If it ends with -ix, its plural ends with -ices. Example: appendix -> appendices.
If it ends with -is, its plural ends with -es. Example: parenthesis -> parentheses.
Oddball words like species maintain their singular form in the plural.
I hope this brief guide helped you. The more you know. Because knowledge is power!
Sunday, February 21, 2010
Thursday, February 18, 2010
Wednesday, February 17, 2010
Not that I blame Dr. Benton, of course. The book is 26 years old. A lot of discoveries have been made, and the book is quite comprehensive for the time. But a look back from over a quarter of a century can be an entertaining experience. A short list of the things said in the book is enough to warrant at least a quiet snicker.
*Tyrannosaurus is the largest carnivore of all time, at 50 feet. (It grew to 43 feet.)
*"Warm-blooded Dinosaurs?" is shown with a skeptical question mark in the index.
*Crocodiles are cited as dinosaurs' closest living relatives. Birds are overlooked.
*Poor Diplodocus is cited as the "most stupid dinosaur", as it has the lowest brain-to-body ratio of any dinosaur. (I don't know if this is still true or not. I'll have to check.
Even the taxonomical differences between then and now are enough to fill this post.
*Tyrannosaurids are Carnosaurs (They're coeulurosaurs.)
*"Anatosaurus", rather than Anatotitan.
*At least it doesn't use "Brontosaurus" as a valid name!
*Oviraptorosaurs are ornithomimosaurs (They're not.)
*All large carnivores, including coelophysoid Dilophosaurus, megalosauroid Megalosaurus and Spinosaurus, and, as mentioned before, tyrannosauroid Tyrannosaurus are apparently Carnosauria.
* Smaller coelophysoids are coelurosaurs (They're not!)
*Therizinosaurus and Deinocheirus are in the Deinocheiridae, which is apparently part of Deinonychosauria. (That's a new one.)
*Elaphrosaurus is an ornithomimosaur (It's a ceratosaur)
*Interestingly, Hypselosaurus is cited as being closely related to Alamosaurus, Saltasaurus, and Titanosaurus, all of which (including Hypselosaurus) would, in 1993, be classed into Titanosauria. (More points for Dr. Benton!)
*It suggests that Mamenchisaurus stood in the middle of ponds and swept around like a vacuum cleaner to eat.
*Noasaurus is claimed to be a deinonychosaur, which would have made it the only of that kind known from South America. Ironically, it wasn't until decades later that unenlagiine dromaeosaurids were found in the same area.
*Pachycephalosaurus is said to be an ornithopod. (It's a cerapod.)
*Though rightfully told to be a saurischian, Segnosaurus is said to be a fish-eater, as this was originally how it was thought to feed. It was, in reality, either herbivorous or omnivorous like other therizinosaurs.
*Spinosaurus is shown as a close relative of Acrocanthosaurus.
*Syntarsus (now Megapnosaurus, or big dead lizard, which is just about the worst dinosaur name ever; no surprise, it wasn't named by actual paleontologists) was one of the first dinosaurs depicted with feathers, but the author approaches this claim with much caution.
But, of course, again, we can't blame Dr. Benton. This was another age (at least in dinosaur science). The book has some very informative parts in the back about the history of the science, as well as the preparation of mounted dinosaur skeletons. And hey. I can assure you, in 2036, paleontologists will be making fun of us for our mistakes. But if we can't laugh at tripods and croc-like bellies, then what can we laugh at?
Tuesday, February 16, 2010
Saturday, February 13, 2010
Wednesday, February 3, 2010
Sunday, January 24, 2010
Thursday, January 7, 2010
(Pictured: Not Texacephale, but its relative Prenocephale)
Texacephale langstoni! This dinosaur was described yesterday from cranial remains found in the Big Bend region of Texas. It has been found to be a relatively pachycephalosaur from the late Campanian in the Cretaceous.
It's helped to rewrite pachycephalosaur taxonomy, too. Classification of this dinosaur has shown that pachycephalosaurs found in Asia, such as Homalocephale and Prenocephale form a monophyletic group. A monophyletic group is determined by whether or not the common ancestor of all members of the group would be considered of that group. For example, the common ancestor of an ostrich and a sparrow would have feathers, wings, and be warm-blooded, and therefore a bird. This means that Aves is a monophyletic group. Whereas the rhino's ancestor is related to horses, an elephant's to seacows, and a hippo's to pigs, which makes the group Pachydermata a non-monophyletic group.
And, surprisingly, analysis of its skull has revived the debate over whether or not pachycephalosaurs could have used their skulls in combat. And here I was, betting on the first dinosaur of 2010 to be yet another theropod.
Friday, January 1, 2010
Wednesday, December 30, 2009
Tuesday, December 29, 2009
Saturday, December 26, 2009
Compared with other mammals (except maybe monotremes such as the platypus), marsupials are remarkably primitive. They bear their undeveloped young in pouches, where the infants nurse until they are able to fend for themselves. Even their appearance is prehistoric, as any American with a trashcan can tell you from experience. They almost look as though they belong in the Mesozoic, rather than the modern day.
The news that these primitive mammals originated in North America has been decided based on a skull found in the Eocene Bighorn Basin of Wyoming, USA. Analysis of the skull, and two 30-million-year-old skeletons, shows that the split between opossums and all other marsupials on the planet occurred about 65 million years ago, at the end of the Cretaceous, in North America.
It is presently thought that marsupials migrated from North to South America until the end of the Cretaceous, when the two continents split (until the Pliocene, at least), and marsupials made their way through Antarctica to Australia, as the southern continent, much warmer in those days, is thought to have connected South America and Australia.
Friday, December 25, 2009
Thursday, December 24, 2009
Dryptosaurus was discovered and named in 1866 by Edward Drinker cope as Laelaps aquilunguis, referring to the Laelaps, a dog of ancient Greek myth. However, it was soon discovered that the name was, as often happens, taken by a genus of mite. It was the first dinosaur to lose its name to a bug, but it certainly was not the last. It was renamed as Dryptosaurus by Othniel C. Marsh in 1877, and the name has, so far, proved valid.
It is thought that Dryptosaurus, one of the dinosaurs endemic to New Jersey, USA, was related to the Early Cretaceous tyrannosaur, Eotyrannus, from England, and it has three fingers on two relatively long front limbs. It is thought that it would have primarily preyed upon the contemporary Hadrosaurus, which was the first dinosaur discovered in the US. Though, due to the rarity of east coast dinosaurs, it is difficult to get a complete picture of Dryptosaurus' diet.
Dryptosaurus was about 20 feet (6.5 meters) long and 6 feet (1.8 meters) tall. It probably weighed a bit over a ton, and was somewhat more gracile than Tyrannosaurus and company. It lived about 70 million years before the present, in the Maastrichtian age of the late Cretaceous.
Saturday, December 12, 2009
Tuesday, August 4, 2009
Consider this: Despite the fact that we refer to Puma concolor outside of science more often as a mountain lion (or depending on where you live, cougar, catamount, etc.), mountain lion is still acceptable as a common name. Because of this, perhaps 'brontosaur' could be adopted as a common name for sauropods, the long-necked dinosaurs. Indeed, this could extend even farther, to generalizing the term 'dinosaur'. To my other paleo-stricken friends out there, I'm sure that an innocent ichthyosaur or mosasaur being slapped with the term 'dinosaur' is like nails on a chalkboard as, in the strictest manner, they do not belong to the Dinosauria. However! I believe it's possible that 'dinosaur' could be accepted as a common name (like how we call certain animals by names of other creatures today, despite their not being closely related). If this were the context of the word, then perhaps Ichthyosaurus, Mosasaurus, Plesiosaurus, and Pteranodon could all be considered 'dinosaurs'; if not for being part of Dinosauria, then at least for resembling them. Just some food for thought!