| “small plunderer” |
CLASSIFICATION
see also: Genus Index, Classification
MEASUREMENTS
TIME
M. zhaoianus: middle Barremian
see also: Ages of the Mesozoic
PLACE
REMAINS
- M.zhaoianus
- [holotype]: articulated skeleton missing middle portion, with patches of preserved integument
ESSAY
| THE “T INY RAPTOR”:Possibly the smallest non-avian dinosaur, assuming (as the authors do) that is is fully grown. PLACEMENT:The counterslab to the hindquarters of this specimen was already published as half of the chimerical Archaeoraptor liaoningensis. The front half of that specimen is actually an avialan. Although the authors classified this species as a dromaeosaurid, it has troodontid features (arctometatarsalian pes, “waisted” teeth, maxilla bordering naris, closely packed dentary teeth) and avialan features (Rahonavis-like ischium, avian features of the teeth, maxilla bordering naris) as well. Some features (rod-like extensions of prezygaopohyses which stiffen the tail, large second pedal ungual) are dromaeosaurid-like. Hopefully this species can shed light on how the three groups are related to each other. Wherever this species belongs, it does not appear to be avian, and thus dispels notions that dinosaurs were too big to be bird ancestors. (This species is smaller than Archaeopteryx, the most primitive bird known.) S MALL AND FUZZY:Feathers or (feather-like integument with a rachis, or vane) similar to those of Beipiaosaurus and Sinornithosaurus are preserved. They are found near the femur, tibia, and ischium. A CLIMBER?:Some features of this species have been interpreted as indicating a scansorial lifestyle. These include distally placed metatarsal and pedal digit I. T RANSITIONAL TEETH:Microraptor has heterodont teeth, the anterior ones being more recurved and laterally compressed and lacking serrations. They are more bird-like than the posterior teeth, and thus may indicate that avian dental traits began in the front and spread to the back over the course of evolution. T ROUBLE WITH THE NAME:Technically, by ICZN rules, this animal should be referred to as Archaeoraptor liaoningensis. However, there will be a petition to reject that name and conserve the name Microraptor zhaoianus. In the hope that this petition goes through, I am using the name Microraptor despite ICZN rules. See the entry on Archaeoraptor for more on this nomenclatural debacle. |
