For those of you who love sauropods, you’ll definitely want to check out the latest issue of Paleobiology. I don’t have enough time right now to give each a full treatment, but here’s a brief summary of each;
- “Modeling growth rates for sauropod dinosaurs” (Thomas M. Lehman and Holly N. Woodward) –
Sauropods were the largest of dinosaurs (and among the largest animals to have ever lived), but how quickly they attained their huge sizes has been hotly debated. Determining how quickly sauropods attained adult size has major implications for considerations of dinosaur metabolism and body temperature, making this area of research important to understanding how dinosaurs lived and evolved. What Lehman and Woodward calculated, contrary to previous studies that had sauropods growing at a faster rate than precocial birds and mammals, was that sauropods grew at a rate between reptiles and birds, taking a longer time (as many as 70 years for Apatosaurus) to reach adult body size. If other recent research is correct, however, dinosaurs may have been reproductively active before reaching adult body size so Apatosaurus may not have had to abstain for seven decades.
- “Comparison of water vapor conductance in a titanosaur egg from the Upper Cretaceous of Argentina and a Megaloolithus siruguei egg from Spain” (Frankie D. Jackson, David J. Varricchio, Robert A. Jackson, Bernat Vila, and Luis M. Chiappe) –
While the title of the paper may not seem like the most riveting of topics, the research presented in the paper is worth noting. Comparing the eggs of two sauropods, Megaloolithus patagonicus from Patagonia and Megaloolithus siruguei from Spain, the researchers were able to hypothesize that these two dinosaurs had different nesting strategies. The eggs from Spain are much larger than those from South America with fewer eggs per clutch, the eggs from South America also differing by having fewer, larger, and irregularly placed pores on the egg. Such clues allowed the researchers to propose that the eggs from South America were not entirely buried during incubation while the ones from Spain were covered, although they note that more taphonomic and paleoecological information is needed to further test their proposal.
- “Ontogenetic stages in the long bone histology of sauropod dinosaurs” (Nicole Klein and Martin Sander) –
Another paper dealing with sauropod growth, using femora & humeri from a much larger sample than in the 1st paper mentioned, this research attempts to identify growth stages for sauropods. The authors identify 13 growth stages generally consistent across the sauropod groups studied, certain histological features in the bone allowing the stages to be readily discerned. (Given these tell-tale signs the authors propose that future descriptions of dinosaur bones where such histology can be studied should include an analysis of ontogenetic stage.) Determining these stages may also help to better analyze the growth rates of sauropods, particularly the question of if they reached sexual maturity before maximum body size.