Tongtianlong limosus – One Very Unusual Fossil Posture

A team of international researchers, scientists from the Chinese Academy of Sciences, Dongyang Museum (Zhejiang Province, China) and Edinburgh University have announced the discovery of a new genus of bird-like dinosaur.  This newest member of the Oviraptoridae family, most likely met its demise when it became trapped in mud.  The animal was preserved with its forelimbs splayed out and outstretched as if beseeching someone or something to help pull it to safety. This dinosaur’s run of bad luck did not end in the Maastrichtian, the specimen was nearly blown up when construction workers were preparing the ground for the building of a new high school.

Two Views of the Fossil Skeleton Material (Tongtianlong limosus)

Tongtianlong fossils.

Two views of the holotype fossil material of Tongtianlong (a) dorsal view and (b) lateral view. Scale bar = 10 cm.

Picture Credit: Nature Scientific Reports (Junchang Lü et al)

Late Cretaceous Southern China was Oviraptorosaur Country

The fossil material, a near complete, three-dimensional specimen was saved by the construction workers, those who had narrowly avoided blasting the last resting place of this sheep-sized dinosaur to smithereens, a drill hole for an explosive charge can even be seen in the pelvic area of the holotype specimen (see photograph above).   The builders did their best to retrieve as much of the fossil material as they could.  With such an amazing skeleton to study, the researchers were quickly able to identify it is an oviraptorid and several unique characteristics led them to describe it as a new species.

An Illustration of Tongtianlong limosus Trapped in Mud

The feathered dinosaur Tongtianlong limosus mired in mud.

Tongtianlong trapped in mud.

Picture Credit: Zhao Chuang

This is the sixth species of oviraptorosaur* to have been discovered in the Upper Cretaceous strata (Nanxiong Formation), exposed in Ganzhou Province (south-eastern China).  The prevalence of oviraptorid fossil material may represent some form of preservation bias, but more likely, the fossil material indicates that this part of world was home to a variety of different types of oviraptorosaur.  Analysis of skull shape and the jaws suggest that each type of oviraptorosaur had evolved to exploit different food resources.  The number of different kinds of this type of dinosaur found in this locality suggests that oviraptorids were undergoing a radiation and rapidly evolving.  As such, these feathered, bird-like dinosaurs, may have been one of the last groups of dinosaur to undergo evolutionary radiation before their extinction.

The Skull of Tongtianlong limosus with Line Drawing  Below

Skull and line drawing of Tongtianlong limosus.

The skull of Tongtianlong with an accompanying line drawing.  Scale bar = 5 cm.

Picture Credit: Nature Scientific Reports (Junchang Lü et al)

Key

aof = antorbital fenestra, bc = braincase, d =dentary, emf = external mandibular fenestra, eo = exoccipital, f -= frontal, j = jugal, l = lacrimal, ltf = lower temporal fenestra, m = maxilla, n = nasal, nar = narial opening, npc = nasopharyngeal canal, o = orbit (eye socket see note), p = parietal, pm = premaxilla, pno = pneumatic opening, po = postorbital, q = quadrate, qj = quadratojugal, sq = squamosal and stf = supratemporal fenestra

Lots of Different Oviraptorid Dinosaurs in the Ecosystem

Tongtianlong is the sixth oviraptorosaurian taxon named from the Nanxiong Formation in this part of south-eastern China.  All these taxa have been named since 2010, the genera are:

  • Banji (B. long) named in 2010 – size unknown.
  • Ganzhousaurus (G.  nankangensis) named in 2013 – size not known.
  • Jiangxiasaurus (J. ganzhouensis) named in 2013 – size not known
  • Nankangia (N. jiangxiensis) named in 2013 – 2.5 metres long.
  • Huanansaurus (H. ganzhouensis) named in 2015 – 2.5 metres in length.

In the scientific paper the researchers explore the possible reasons why there were so many oviraptorids in Late Cretaceous southern China.  It could be due to “taxonomic inflation”, some of the specimens described could in fact be males or females of already known species or perhaps the fossils could represent already described species of dinosaur but different growth stages.  The scenario the scientists favour is that the fossils are documentary evidence supporting the idea that there was a genuine radiation of oviraptorosaurs.

The Scientific Paper: A Late Cretaceous Diversification of Asian Oviraptorid Dinosaurs: Evidence from a New Species Preserved in an Unusual Posture

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