latter, if valid, would have had priority under the International Code of Zoological Nomenclature. However, there is some doubt whether Olson in fact succeeded in meeting all the formal requirements for establishing a new taxon. Namely, Olson designated the specimen as a lectotype, before an actual type species was formally erected. A similar situation arose with Tyrannosaurus rex and Manospondylus gigas, in which the former became a nomen protectum and the latter a nomen oblitum due to revisions in the ICZN rules that took place on December 31, 1999. In addition, Xu's name for the type specimen (Microraptor) was subsequently used more frequently than the original name; as such, this and the chimeric nature of the specimen would render the name "Archaeoraptor" a nomen vanum (as it was improperly described) and the junior synonym Microraptor a nomen protectum (as it's been used in more published works than "Archaeoraptor" and was properly described). Additional specimens The first specimen referred to Microraptor represented a small individual and included faint feather remnants, but was otherwise not well preserved and lacked a skull. In 2002 Mark Norell et al. described another specimen, BPM 1 3-13, which they did not name or refer to an existing species. Later that year Stephen Czerkas et al. named the specimen Cryptovolans pauli, and referred two additional specimens (the first to show well-preserved feathers) to this species. The generic name was derived from Greek kryptos, "hidden", and Latin volans, "flying". The specific name, pauli, honors paleontologist Gregory S. Paul, who had long proposed that dromaeosaurids evolved from flying ancestors. The type specimens of C. pauli were collected from the Jiufotang Formation, dating from the early Albian and now belong to the collection of the Paleontology Museum of Beipiao, in Liaoning, China. They are referred to by the inventory numbers LPM 0200, the holotype; LPM 0201, its counterslab (slab and counterslab together represent the earlier BPM 1 3-13); and the paratype LPM 0159, a smaller skeleton. Both individuals are preserved as articulated compression fossils; they are reasonably complete but partially damaged. Czerkas et al. (2002) diagnosed the genus on the basis of having primary feathers (which in the authors' opinion made it a bird), a co-ossified sternum, a tail consisting of 28 to 30 vertebrae and a third finger with a short phalanx III-3. Some of the feathers Czerkas described as primary were actually attached to the leg, rather than