The vampire pterosaur has a new sister: Daohugoupterus

Cheng et al. (2014)
present a new small, late Jurassic pterosaur, Daohugoupterus. They were not quite sure what it was, assigning it to Pterosauria incerta sedis. The specimen is represented by an articulated skeleton lacking hind limbs, the anterior skull and two proximal wing phalanges (Fig. 1). Wing tip soft tissue was preserved. I believe the ulna and radius are just beneath the surface based on the positions of the humerus and carpus/metacarpus. The rest of the wing is likely twisted beneath these elements as the distal two wing phalanges frame the soft tissue.

Figure 1. Click to enlarge. Daohugoupterus in situ, colorized (left) and as originally traced (right). You'll note that DGS pulled out more details than firsthand tracing.

Figure 1. Click to enlarge. Daohugoupterus in situ, colorized (left) and as originally traced (right). You’ll note that DGS pulled out more details than firsthand tracing.

From their abstract:
“Daohugou is an important locality of the Jurassic Yanliao Biota, where
only two pterosaurs have been described so far (Jeholopterus and
Pterorhynchus). Here we report a new genus and species, Daohugoupterus
delicatus gen. et sp. nov. (IVPP V12537), from this region, consisting
of a partial skeleton with soft tissue. The skull is laterally
compressed, differing from Jeholopterus. The antorbital fenestra is
larger than in Pterorhynchus. The upper temporal fenestra is unusually
small. The short cervical vertebrae bearing cervical ribs indicate
that it is a non-pterodactyloid flying reptile. The sternal plate is
triangular, being much wider than long. The deltopectoral crest of
humerus is positioned proximally and does not extend further down the
shaft, a typical feature of basal pterosaurs. Daohugoupterus also
differs from the wukongopterids and scaphognathids from the Tiaojishan
Formation at Linglongta, regarded to be about the same age as the
Daohugou Bed. The new specimen increases the Jurassic
non-pterodactyloid pterosaur diversity of the Yanliao Biota and is the
smallest pterosaur from Daohugou area so far.”

DGS
Digital Graphic Segregation was used to pull details out of the skeleton. While the original paper described small upper temporal fenestra (that are indeed there) the figure did not show this detail. No skull bones were identified. The vertebrae were outlined without details. Color tracing and reconstruction (fig. 2) help bring this specimen ‘back to life.’ The length of the rostrum is unknown, but after phylogenetic analysis nesting with Jeholopterus, the rostrum was reconstructed like it’s sister taxon.

Reconstruction
A reconstruction of all available elements resulted in a sister to Jeholopterus, sharing many traits including the strong reduction of anterior cervical vertebrae, robust cervical vertebrae posteriorly, wide ribs creating a pancake-like torso, and a fragile skull with very large orbit (Fig. 2). Notably, Jeholopterus was a contemporary from the same Late Jurassic formation.

Figure 2. Click to enlarge. Daohugoupterus reconstructed.

Figure 2. Click to enlarge. Daohugoupterus reconstructed.

If you take a bone-by-bone survey
of the the DGS tracing vs. the original tracing (Fig. 1), you’ll find many differences. This is a difficult fossil and the accuracy of my tracings depending to a large part on testing each part within an evolving reconstruction (Fig. 3). Attempting reconstructions of roadkill pterosaurs is something conventional paleontologists are loathe to do, and they never ask me to help. Hence this blog.

Figure 1. Jeholopterus in lateral view. Note the extreme length of the dermal fibers, unmatched by other pterosaurs.

Figure 3. Jeholopterus in lateral view. Note the wide ribs.

In a side-by-side comparison (Fig. 4)
Jeholopterus and Daohugoupterus do share many traits and are roughly the same size. Daohugoupterus does not have the robust limbs and surgically curved claws that Jeholopterus has, but Daohugoupterus does have enormous eyes, probably for night vison. They share a wider than deep torso which enables them to cram their bellies, but still keep an aerodynamic disc-like shape (also see Sharovipteryx for something similar). They also share a very robust neck that gets very gracile close to the skull. I presume this gives both pterosaurs a wider range of motion at the skull/neck juncture. But why does most of the neck have to be stronger than the dorsal vertebrae?

Figure 3. Jeholopterus and Daohugoupterus in side-by-side comparison to scale. The wings were relatively short in Daohugoupterus and the pelvis was small. The skull was relatively narrower, but the torso was just as broad.

Figure 3. Jeholopterus and Daohugoupterus in side-by-side comparison to scale. The wings were relatively short in Daohugoupterus and the pelvis was small. The skull was relatively narrower, but the torso was just as broad.

On a side note
Experiment.com has accepted by submission and my first crowd-source funding project has started today. See details at:
https://experiment.com/projects/the-reptile-evolution-project

References
Cheng X, Wang X, Jiang S and Kellner AWA 2014. Short note on a non-pterodactyloid pterosaur from Upper Jurassic deposits of Inner Mongolia, China. Historical Biology (advance online publication) DOI:10.1080/08912963.2014.974038

 

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