Saturday, November 24, 2012

Coming Soon: A Field Guide to Mesozoic Birds

The cover, featuring two
squabbling Boluochia
As some of you may have seen when I teased this on Facebook a few weeks ago, I've gone and written a book! With the pithy, concise title of A Field Guide to Mesozoic Birds and Other Winged Dinosaurs, this has been nearly three years in the making, and should be available soon through my website and

As the name implies, the book is a heavily illustrated "field guide" style summary of known "birds" from the dinosaur era (including deinonychosaurians, caenagnathiformes, and avialans), focusing on most likely life appearances and highlighting what kinds of features may have distinguished each species in life. The book also contains a lengthy introductory section on bird evolution, and on the principles that help in reconstructing life appearance (such as feather arrangement, inferring coloration, distribution of feather types, etc.). Some of this is adapted from research I'd done previously for DinoGoss (such as the section on feather colors), but expanded and updated, and most of it consists of brand new material. The artwork is also pretty much all-new; while some of it had originally been uploaded to my DeviantArt profile (some of you may have seen my entry on caudipterids), most of those pieces ended up being completely re-drawn by the time the book was finished.

The Field Guide covers over 150 species, usually illustrated in multiple views (chosen based on ecology, and with dorsal-view wingspan profiles where appropriate), and each comes with one of my obligatory scale charts. By the time I was finished, I was surprised by how hefty the book turned out. The original conception for the book, as suggested by John Conway, had been to illustrate all "reconstructible" aviremigians--by that, I assume he meant stuff with pretty much complete skeletons. I tried to limit myself to anything with something both distinguishable and visible in life (and pretty much anything with any skull material) despite the urge to produce a few super-speculative pieces (one or two of which made it into the final cut). Anything that couldn't solidly be reconstructed based on skeletal evidence or at least decent phylogenetic bracketing is relegated to an appendix listing all excluded species, but even so, I was a bit surprised that I could manage nearly 150 pretty well-supported illustrations.

Unfortunately (or perhaps fortunately given that it would have taken me another two years to finish), I was just wrapping this book up when two surprising pieces of news surfaced--one, the discovery of pennaceous feathers in ornithomimosaurs, making all of Maniraptoriformes possible aviremigians, and news of a forthcoming study which finds microraptorians, unenlagiines, and troodontids to be avialans and scansoriopterygids to be basal coelurosaurs (potentially making most of coelurosauria aviremigians!). I did manage to include a little discussion of the former in the book, but it will be interesting to read the details of the latter in December. If Scansoriopteryx, which seems to have vaned wing feathers, is actually a fairly basal coelurosaur, a pretty massive supplementary volume may be in order.
Preview of an interior spread featuring Protarchaeopteryx and Caudipteryx.

As I mentioned above, the impetus for this project really came from John Conway, who suggested a guide to all aviremigians based on my field guide style drawings on dA. Unbeknownst to John, I had actually been planning a field guide to the Yixian fauna and flora at the time, but a really comprehensive guide to all Mesozoic "birds" seemed like too good an idea to pass up. John also suggested the idea to self-publish rather than seek traditional publication, which he has been discussing lately on his tumblr.

Due to the vagaries of the publication process, I don't have a definite release date yet, but barring any major hurdles the Guide should be available to order online in paperback before the end of December, so start writing those letters to Santa! Retail price is $36.95 plus shipping from Amazon US or CreateSpace Direct, and it will likely be available at around £25 from Amazon UK and around 36 from Amazon Europe.

Friday, November 2, 2012

The Flying Longipterygids

I started to get a little carried away in my previous post on longirostrisavisine tails, so I decided to split the finished post in half and use this one to delve a little more into the possible implications the odd tails and clawless wings of that group would have had on their flight styles.

As mentioned previously,  longirostravisines, unlike most other enantiornitheans, lacked claws on all three of their manual digits, a trait apparently acquired separately of the Carinatae (Ichthyornis + modern birds). In the last post I speculated that this might have reflected a distinct flying (or at least landing) style. But how much do we really know about longipterygid flight?

Fig. 10 from Close & Rayfield 2012, click to big it up. Note the three general clusters of continuous-flapping (red), soaring and flightless (yellow and gray), and bizarro enantiornithean style (green).

In their recent paper, Close & Rayfield attempted to correlate wishbone (furcula) shape with flight style. Many enantiornitheans in the analysis plotted together in a cluster well separated from modern birds, but close to basal avialans like Confuciusornis which are usually presumed to have been gliders. Oddly, in the Close & Rayfield figure reproduced above, Rapaxavis (no. 103), a longirostravisine, clusters with the weirdo enantiornithean-style fliers, while more basal longipterygid Longipteryx (no. 98) groups with continuous-flapping fliers and is marked as an ornithurine (something seems off here).

In another recent open-access paper on Mesozoic bird flight styles, Wang et. al (2011), using wing element and primary feather length ratios, found Longirostrisavis to be a continuous-flapping flier, and Longipteryx either a continuous-flapping or a flap-gliding flier, roughly the opposite result of the Close & Rayfield furcula-based analysis.

 The fact that two independent analyses using two distinct methods produced different results probably does not bode well for the precision of either method. Clearly, we need to figure out better methods to more reliably tests flight styles in extinct birds.