The Humble Origins of the Ornithocheiridae

Earlier we looked at a tiny pterosaur attributed to Pterodactylus” pulchellus at the British Museum of Natural History (NHM  42735) and its ancestry to cycnorhamphids and ornithocheirids. We also looked at the tiny Nohra ornithocheirid from Lebanon. Today we’ll look at these taxa to scale (Fig. 1).

Figure 1. Click to enlarge. The origin of the Ornithocheiridae begins with tiny  "Pterodactylus" pulchellus and continues with the much larger Yixianopterus and the hypothetical adult to the JZMP embryo. Then a size reduction (or is it a juvenile?) to the Nohra Lebanon pterosaur followed by Haopterus, itself about seagull-sized. Thereafter ornithocheirids get larger.

Figure 1. Click to enlarge. The origin of the Ornithocheiridae begins with tiny “Pterodactylus” pulchellus and continues with the much larger Yixianopterus and the hypothetical adult to the JZMP embryo. Then a size reduction (or is it a juvenile?) to the Nohra Lebanon pterosaur followed by Haopterus, itself about seagull-sized. Thereafter ornithocheirids get larger.

From humble beginnings
P. pulchellus (Late Jurassic, Solnhofen) is about as tiny as pterosaurs get. Yet it had already developed traits that put it at the evolutionary crossroads that produced cycnorhamphids in the Solnhofen and yixianopterids (basal ornithocheirids) in the Yixian formation (Early Cretaceous) of China. Other than this specimen, ornithocheirids are curiously absent from the Solnhofen, but by the early Cretaceous they had spread worldwide.

Yet another size reduction – or is it a juvenile?
The Nohra specimen from Lebanon is oddly smaller than its phylogenetic sisters. The only thing holding us back from calling it a juvenile is the relative rarity of juveniles in the fossil record and the presence of small Haopterus ( Fig. 1) as a sister taxon. At this point the Nohra specimen testifies to the unexplored variety in morphology and size that pterosaurs present us.

You can see more ornithocheirids to scale here.

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