Ikrandraco avatar – a new pterosaur & DGS reveals a few more bones

A recent paper
by Wang et al. (2014) described a wonderful new Chinese ornithocheirid, Ikrandraco avatar, with a crest below the mandible, not above the rostrum. Actually two specimens were found with slightly different preservations.

Figure 1. Click to enlarge. Ikrandraco avatar skull. As originally traced (below) with DGS (above).

Figure 1. Click to enlarge. Ikrandraco avatar skull. As originally traced (below) with DGS (above).

This wonderful new ornithocheirid (not a pteranodontoid) from the Jiufotang formation (Early Cretaceous). The authors report, “We propose that this pterosaur fed on fishes from nearby freshwater lakes by flying low over the water, capturing its prey by lowering the mandible in the water, being capable of a reduced and temporary skimming. We also propose that it had a more developed throat pouch then in other pterosaur species.”

The mandible was quite sharp. The rostrum was not. Oddly the teeth appear to have emerged from the sides of the rostrum and mandible. The alveoli were like portholes on a ship’s hull.

Figure 2. Ikrandraco in situ. Below as originally traced. Above with femur, tibia, pelvis and tail traced and manual 4.4 identified (not a rib).

Figure 2. Ikrandraco in situ. Click to enlarge. Below as originally traced. Above with femur, tibia, pelvis and tail traced and manual 4.4 identified (not a rib).

The authors were able to identify the tiny metatarsals and sacrum, but overlooked the tibia, femur, pelvis and tail, shown here (Fig. 2). And yes, that fossil is no closer to me than half a world away. I wouldn’t have looked fro the tibia and femur, but there was the metatarsus, all by itself, lined up with a crack that split the tibia. What I see of the bones are either impressions of bones that were once there, or they remained buried, just below the surface.

Figure 3. DGS restores the known elements to a more in vivo pose of Ikrandraco.

Figure 3. DGS restores the known elements to a more in vivo pose of Ikrandraco. The tiny premaxilla had tiny teeth. Rather than having a nice anhanguerid-like rake and spoonbill, this pterosaurs evolved a very narrow set of jaws. The deep angle of the quadrate absorbed shocks as the lower jaw slid through the water. 

The authors considered this an adult individual based on the fusion of the extensor tendon, but that is a phylogenetic feature shared with several ornithocheirids, large and small.

Other ornithocheirids can be seen here for comparison. Most have longer teeth. Wang et al. (2014) nested Ikrandraco with Nurhachius and Istiodactylus among pterosaurs known from more than just scraps. I haven’t done the work, but that seems reasonable, except that the orbit doesn’t have the keyhole shape. Among pterosaurs with rostral crests and large round orbits, we look to Criorhyrhynchus and Coloborhyrhynchus, which are related to istiodactylids. Unfortunately the authors nested ornithocheirds derived from a sister to sharp-snouted Pteranodon from the Late Cretaceous. That doesn’t make sense. The large pterosaur tree derives ornithocheirids from scaphognathids, sisters to cycnorhamphids and Yixianopterus is a basal ornithocheirid (not included in Wang et al. (2014).

The Ornithocheiridae.

Figure 4. The Ornithocheiridae. Click to enlarge and expand. Look for the taxon that shares the most traits with Ikrandraco. In size Ikrandraco was relatively small, about as tall as Boreopterus. 

 

 

 

References
Wang X, Rodrigues T, Jiang S, Cheng X and Kellner AWA 2014. An Early Cretaceous pterosaur with an unusual mandibular crest from China and a potential novel feeding strategy. Scientific Reports 4 : 6329, pp. 1-9. | DOI: 10.1038/srep06329

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