Raptor's Nest

Finally, I have completed my Pachyrhinosaurus ! I started it around October of 2008 , but with the subsequent job hunt and pushing papers out I hardly had time to make progress with it, and it ended up taking more than two years. Anyway, here it is. This is mostly done by referencing some photos given to me by Traumador Tyrannosaur... well, mostly the skull that is; the body is a generic ceratopsian. My fiancée asked me "why do you keep drawing the same dinosaur?" to which I replied "...but they all have different horns". I'm not sure I convinced her but that's essentially centrosaurs in a nutshell; very diverse cranial morphology in an otherwise conservative body plan. I even read somewhere that Greg Paul lumped all centrosaurs into the genus Centrosaurus in his newest book The   Princeton Field Guide to Dinosaurs (but I haven't read it yet). When I draw dinosaurs, I usually just draw rough outlines of the animal with very limited skeletal reco...

Today, I bring you the third instalment of my perching dino/bird series...my orange Microraptor . I was originally trying to draw Archaeopteryx but realised halfway through that the face was too theropod-looking and decided that I was going to convert it into a Microraptor . Actually, this one is even drawn before my blue Archaeopteryx , so I'm posting things counter-chronologically. But that's not strictly true because I only coloured this sketch in today, so it is technically my newest drawing. I tried to pose this Microraptor with a half-folded wing; kind of like a bird folding up its wings after either landing on the branch or just extending them out for whatever reason birds extend their wings from time to time. Aside from the obviously interesting point of having tarsal "flight" feathers, Microraptor also is quite interesting in that it has really long primary feathers on the wings proper. Colouring is as suggested to me by my fiancée, who apparently does...

This is another rendering of Archaeopteryx , one I'd done before I'd done my red  Archaeopteryx . Just like my red Archaeopteryx , I made this guy's head and neck quite fluffy. The colouring is loosely based on a blue jay because I really like blue jays. But also corvids in general; corvids are cool! ...but then in hind sight, it looks a bit too much like a corvid than an Archaeopteryx , I must admit, but this is all in an attempt to make Archaeopteryx look more birdlike rather than a feathered reptile; I think most of the artistic reconstructions out there are too reptilian. I wrote in my red Archaeopteryx post as well but I kind of like the idea that Archaeopteryx and other early birds had more fuzziness about them than widely depicted. Before anyone says, "How is this an Archaeopteryx , it just looks like a bird?", look at the fluff on the tarsals. And look at the external nares at the tip of the premaxilla. Also, do look at the claws poking out from und...

After a very prolonged hiatus in palaeoart, today I bring you Archaeopteryx , the 'first' bird. I've recently been drawing various interpretations of fossil birds, primarily Archaeopteryx and Confuciusornis , but this rendering is one of my favourites so far. A red Archaeopteryx perched on a branch. I've come to notice that Archaeopteryx  is most frequently reconstructed with very short feathers along the head and neck. Indeed in the Berlin specimen, there seems to be a general lack of long feathers around the head and neck other than faint striations (Christiansen & Bonde, 2004). Christiansen & Bonde (2004) offer two hypotheses regarding the preservation of contour feathers in Archaeopteryx : 1, the fossil is an accurate representation of plumage in life; and 2, feathers were present but lost during fossilisation. The authors seem to prefer hypothesis 1 and suggest that Archaeopteryx had mixed coverings of large pennaceous feathers and short simple proto...

For my third post on my R tutorials for beginners and intermediate users, I shall finally touch on the subject matter that prompted me to start these tutorials - plotting with group structures in colour. If you are familiar with R, then you may have noticed that assigning group structure is not all that straightforward. You can have a dataset that may have a column specifically for group structure such as this: B0 B1 B2 Family Acrocanthosaurus 0.308 -0.00329 3.28E-05 Allosauroidea Allosaurus 0.302 -0.00285 2.04E-05 Allosauroidea Archaeopteryx 0.142 -0.000871 2.98E-06 Aves Bambiraptor 0.182 -0.00161 1.10E-05 Dromaeosauridae Baryonychid 0.189 -0.00238 2.20E-05 Basal_Tetanurae Carcharodontosaurus 0.369 -0.00502 5.82E-05 Allosauroidea Carnotaurus 0.312 -0.00324 2.94E-05 Neoceratosauria Ceratosaurus 0.377 -0.00522 6.07E-05 Neoceratosauria Citipati 0.278 -0.00119 5.08E-06 Ovir...

For my second post on R, I think I will address how to extract subsets of data based on some selection criterion like taxon names. For instance, I have a huge dataset of morphometric variables for at least 36 species of cats (living and fossil). Sometimes I'd like to do some stats on a subset of this dataset, like all the living cats or just on the Panthera lineage species ( Panthera and Neofelis ). Till recently, I've been doing most of my dataset manipulation in Excel by filtering out certain taxa from the spreadsheet and copy-pasting to a text file, which I read into R. However, you can select subsets of data in R based on taxon names. In my dataset that I call cat , I have a column labelled Taxa which contains all my taxon names. So typing cat$Taxa would be the way to call up my taxon names. Let's say I want to extract from my dataset cat just the data for the lion Panthera leo . The associated taxon names in cat$Taxa would be Panthera_leo . So to extract that ...

I was flipping through an old sketch book yesterday (only because I was looking for spare large-sized sketch paper for some possible figures in preparation for a manuscript I'm currently working on) and I came across a few old dinosaur drawings that I had completely forgotten about. I present one here. It's an Allosaurus  squatting behind some foliage waiting for the right moment to burst out to attack the group of Stegosaurus . It's even inching forward little by little to get to the perfect position. I wouldn't be surprised if Allosaurus was an ambush predator; lying in wait till the right time to attack, then sprinting up to its prey and delivering a slashing bite to inflict serious wounds to its prey. With it's relatively small teeth, Allosaurus  doesn't fit the bill for an average theropod (even though it is frequently cited as being the quintessential theropod). However, Allosaurus had an incredible gape and very strong neck muscles. So Bakker (1998)...