Wednesday, April 16, 2008

Rugodracos arborealis

One of the many oddities of the Draconia is that for every flighted species you find, there is at least one flightless, or near-flightless, species. Mooney (1962) hypothesized that once dragons reach a certain size, weight restrictions kick in, and flightlessness in inevitable. He was puzzled, however, by Megalodracos, a beast almost as large as Sinuospondylus and fully capable of flight. Still, Mooney suggested that the basalmost dragons were small and evolved flight as a means of prey capture or escape from predators. As their size increased, many dragons abandoned a flighted way of life, content in being the apex predators (or herbivores) in their environments and no longer needing to fly. As flight capability decreased, the wing structure simplified. Mooney referenced Tauropesa, Sinuospondylus, Chasmodracos, and Rugodracos as evidence of this path to flightlessness.

Rugodracos arborealis, the "arboreal dragon king," is an southeast Asian dragon, generally found in Vietnam, which is flightless in the proper sense, but uses its narrow wings to briefly glide from tree to tree. At fifteen feet long, Rugodracos isn't as large as one would suspect to be flightless, but its unique lifestyle may provide a different motivation. The dragon was described in 1973 by Brizby after an expedition into the jungles to observe the aquatic habits of constrictors. He took the animal's cranial frill to be a crown, and named it king of the dragons. Indeed, Rugodracos' frill is unique among dragons, and brings to mind ceratopsian dinosaurs like Triceratops and Centrosaurus. The frill doesn't seem to have a practical purpose, and males have squared-off frills more ornamented with smaller horns and scutes than females, who have a more rounded frill. Like ceratopsian dinosaurs, the frill is made up of the parietal and squamosal bones, although there are fenestrae, like those of ceratopsians.

A large nasal horn core erupts from the nasal bones on males. The head is roughly triangular in males, and both sexes develop a rostral bone and predentary for use in clipping off vegetation. In general, Rugodracos is a slow-moving, gentle animal, and fights between rival males are extremely rare--in general, scores are settled via extended threat displays.

Rugodracos' body is uniquely adapted for climbing. Its arms and legs and long and muscular, and both the hand and foot are equiped with an offset first phalanx for grasping branches. The tail is not inherently prehensile, but does supply some leverage while moving through the canopy. The body is long, and large irregularly-placed spines run down the back from the neck to the end of the tail. Rugodracos' wings are long but spindly, featuring little mobility between the joints. The patagium is similarly narrow, and the portion that would usually run from the back of the fourth finger to the body only reaches midway down the humerus. In general, Rugodracos keeps its wings lying against the body, but uses the wings in threat displays extensively. Male and female dragons are green with lighter underbellies and yellowish patagia. Males, however, have bright orange splots running down each side of their bodies and along the cheiropatagia.

Brizby noted that the dragons seem very lazy, spending most of their days sitting on branches and sleeping. He also noted that younger dragons, who seemed to have not yet "grown into" their wings, used their narrow airfoils to glide from branches to a neighboring tree trunk. He never noted adults to do this, however. "At a certain age," Brizby wrote, "gliding is entirely replaced by display behavior." He theorized that a similar phenomenon had occurred during Sinuospondylus' loss of flight, although he did note that the monster's great size and vegetarian diet probably played important roles as well. Rugodracos similarly prefer leafy greens, although individuals will snatch up small vertebrates including mammals and birds when such prey accidentally comes within striking distance of the dragon. Juvenile dragons did not often hunt, but seemed excited by it, and would often pursue prey once it was close enough to them. Adults, however, seemed to prefer a more lethargic, passive existance (Sampson, 1992). Although the two dragons generally live in the same kind of environement, Rugodracos and Palusodracos do not seem to co-habituate.

Sampson compared the animals to chameleons and sloths, noting that even when approached by humans, the dragons would, at the most, bob their heads before moving away. Most would simply stand their ground and continue munching on leaves. Given their passivity, Sampson wondered how their numbers had not been demolished by local hunting practices, and this is still unknown. During a trip to Vietnam in 2001, draconologist Richard Henderson asked why dragon was not on the menu of a local restaurant, to which he was informed that dragon meat is "poisonous." A person sitting at a table next to him reportedly told him that killing a king dragon is "bad luck." Whether the venomosity of king dragon flesh is superstition or fact has not been investigated. Henderson is currently living in a small camp in Rugodracos territory with the goal of writing a detailed monograph of the creature's habits upon his return.

Taxonomically, Rugodracos may, bizarrely, share a recent ancestry with Felimimus paradoxus. Both genera show similar limb proportions and some braincase similarities (Phelps & Nash, 2004). Fossils of Rugodracos or related animals are unknown, although given its preferred habitat (swampy jungles), the chances of fossilization are ridiculously low. Decomposition in such environments happens extremely quickly, and the brackish swampbeds, though rife with organic material, are no friend to taphonomic processes. Irwin & Jones (1978) found Harenadracos tridactylus to nest, at least distantly, with Rugodracos based on limb anatomy and the shared rostral bone.


Brizby, G. (1973). A new tree-dwelling dragon from North Vietnam. Draconium 40(2): 246-269.

Mooney, B. D. (1962). Does wing structure simplification lead to flightlessness? European Journal of Draconology 52(3): 368-381.

Sampson, B. (1992). Comments on Brizby's Rugodracos aborealis. Brevia (March): 46-48.

Phelps, F. & Nash, D. (2004). Phylogenetic re-evaluation of the bizarre cat mimic dragon, Felimimus paradoxus. In Dragons of the World (Carpenter, ed.). Prince Rupert Press: 89-111.

Irwin, B. E. & Jones, D. (1978). Monophyly of the Draconia. Draconium 19(1): 25-59.

Coming up: Chasmodracos bentoni, one of the few facultatively bipedal dragons!

1 comment:

lantaro said...

Nice! One of my favorites thus far! I have to say, I am amazed that a group of scientists was able to go on a studying expedition into the jungles during the height of the Vietnam war. Ah well, more power to them, I suppose.