Pterosaur Fingers – Part 5, Scaphognathus to Cycnorhamphids and Ornithocheirids

Earlier we looked at the evolution of the fingers of basal pterosaurs and dimorphodontids, basal eudimorphdontids, campylognathoides and rhamphorhynchus, and most recently dorygnathids leading to azhdarchids and ctenochasmatids. Today we’ll look at scaphognathids to cycnorhamphids and ornithocheirids.

Pterosaur fingers

Figure 1. Click to enlarge. Pterosaur fingers, Scaphognathus to cycnorhamphids and ornithocheirids

Jiangchangopterus – Compare to the outgroup taxon, Changchengopterus, with similar overall proportions. Manual 3.1 was the shortest phalanx.

Scaphognathus crassirostris (holotype) – The metatarsus was shorter. Manual 3.2 was longer. The digits were more robust. The unguals were larger.

Scaphognathus SMNS 59395 – The digits were relatively longer.

Scaphognathus (Maxburg specimen) – The metatarsus was longer. The digits were shorter. The unguals were shorter. Manual 3.2 was shorter.

Gmu 10157 – The metatarsus was longer. The digits were shorter. Ungual 1.1 was larger.

TM 10134 – The metatarsus was more gracile. The digits were relatively smaller. Manual 2.1 and m3.1 were relatively longer. The unguals were smaller.

BSp 1986 XV 132 – The metatarsus was relatively longer. The digits were much shorter with smaller unguals.

No. 30 – The proximal metatarsus was more robust. The fingers were longer, but shorter than those of Gmu 10157.

Cycnorhamphus – The proximal phalanges were longer. The penultimate phalanges were shorter.

Yixianopterus – Compare to outgroup sister taxon TM 10134. (This data was difficult to gather and may include errors. It certainly includes some autapomorphies.) The metatarsus was more robust. Manual 1.1 was longer. As in the Maxburg specimen the penultimate phalanges were longer.

Lebanon specimen (MSNM V3881) – The digits were smaller. Digit 1 was not elongated as in Yixianopterus.

JZMP embryo – The digits were relatively the largest among all ornithocheirids (a possible juvenile trait?) Digits 3 and 2 nearly the same length.

Haopterus – The digits were mid-sized. The unguals were smaller. The digits were more gracile.

Boreopterus – The digits were relatively shorter with smaller unguals. Manual 3.2 was a disc. The unguals were larger.

Zhenyuanopterus – Manual 3.1 was shorter and shorter than m2.1. Manual 3.2 was longer.

Arthurdactylus -The digits were more gracile and longer with smaller unguals.

Nurhachius – The proximal metatarsus was twice the width of the distal end. The digits were much shorter and smaller with relatively large unguals. Manual 3.2 was a disc. Manual 2.2 was longer than m3.3

Istiodactylus – Digits 1-3 were subequal and nearly identical, composed of only two phalanges (including the ungual) each, which is unique in pterosaurs.

Brasileodactylus – The digits were long with larger unguals.

Anhanguera – The digits were more robust. The unguals were deeper.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

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