America's smallest dinosaur uncovered
An unusual breed of dinosaur that was the size of a chicken, ran on two legs and scoured the ancient forest floor for termites is the smallest dinosaur species found in North America, according to a University of Calgary researcher who analyzed bones found during the excavation of an ancient bone bed near Red Deer, Alberta.
"These are bizarre animals. They have long and slender legs, stumpy arms with huge claws and tweezer-like jaws. They look like an animal created by Dr. Seuss," said Nick Longrich, a paleontology research associate in the Department of Biological Sciences. "This appears to be the smallest dinosaur yet discovered in North America."
Called Albertonykus borealis, the slender bird-like creature is a new member of the family Alvarezsauridae and is one of only a few such fossils found outside of South America and Asia. In a paper published in the current issue of the journal Cretaceous Research, Longrich and University of Alberta paleontologist Philip Currie describe the specimen and explain how it it likely specialized in consuming termites by using its small but powerful forelimbs to tear into logs.
"Proportionately, the forelimbs are shorter than in a Tyrannosaurus but they are powerfully-built, so they seem to have served a purpose," Longrich said. "They are built for digging but too short to burrow, so we think they may have been used to rip open log in search of insects."
Longrich studied 70 million-year-old bones that were collected on a dig led by Currie at Dry Island Buffalo Jump Provincial Park in 2002 where the remains of more than 20 Albertosaurus sarcophagus individuals were found. Albertosaurs are a type of tyrannosaur. The bones were placed in storage at the Royal Tyrrell Museum and Longrich came across them while trying to compare Albertosaurus claws to another dinosaur species.
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Evolving the Single Daddy
What do a tree that lives in the deserts of Algeria, an Asian freshwater clam and a stick insect from Sicily have in common?
The answer is that each of them has evolved a strange form of asexuality. Why strange? It involves males.
Sex, to get technical about it, is the mixing of genes from two parents to make a new individual that has a genetic contribution from both. Asexuality thus refers to any of a number of forms of reproduction that involve only one genetic parent.
That parent is typically the female. The reason is that, in many species, females can easily reproduce without males. An egg, after all, contains nutrients and other stuff that an embryo needs in order to grow. Often, the only thing the egg is missing is the set of genes that comes from the father. But this set of genes can sometimes be dispensed with - the egg can develop without it. As a consequence, females in species from aphids to dandelions are the ultimate single mothers: they reproduce without males, and each is the sole genetic parent of her offspring.
An interesting op-ed piece from the New York Times.