Pterosaur Fingers – Part 4, Dorygnathus to Ctenochasmatids

Earlier we looked at dimorphodontid and basal eudimorphodontid hands. Today we’ll take a look at the clade that begins with the Donau specimen of Dorygnathus and ends with Pterodaustro.

Dorygnathus to Ctenochasmatid hands

Figure 2. Dorygnathus to Ctenochasmatid hands. Not to scale. Click to enlarge.

The trend here is to a longer metacarpus, but not coincident with the reduction of the tail. The fingers and unguals were much smaller in the beach-combing ctenochasmatids, probably indicating no further need of trees to grapple.

Fenghuangopterus? (Dorygnathus species) – Compare to the outgroup taxon, Dorygnathus, the Donau specimen. Metacarpal 4 was more robust. Metacarpal 2 was subequal to mc3. Digits 2 and 3 were shorter. Manual 3.2 was no longer than wide.

Dorygnathus SMNS 55886 – The digits were relatively shorter and more gracile.

Dorygnathus R 156 – The metatarsus was smaller and the digits were longer with larger unguals. Manual 3.2 was longer than wide.

The St/Ei 1 specimen attributed to Pterodactylus – The metatarsus was a quarter longer. Manual 3.2 was nearly as long at m3.1. Smaller unguals. The drastic reduction in the tail places this taxon in the pterodactyloid-grade, but the metacarpus was not elongated.

MB.R.3530.1, No. 40 (Wellnhofer 1970) – The metacarpus was a wee bit shorter. Unguals were smaller.

Ctenochasma elegans (private specimen) – The metacarpus was nearly twice as long. Manual 1.1 was shorter and subequal to m2.1. Manual 3.3 was shorter than m3.1. The unguals were reduced to no deeper than the penultimate phalanges.

Ctenochasma? elegans (a small Gnathosaurus species) AMNH 5147 – The metacarpus was slightly longer. Manual 1.1 was longer.

Pterodactylus? micronyx (Pester specimen) – Manual 1.1 was shorter than m2.1, which was longer than m2.2.

Ctenochasma elegans No. 45 – The digits were shorter and more robust. The proximal phalanges were all subequal.

Ctenochasma gracile, No. 65 – The metacarpus was longer and more gracile. The digits were more gracile. Manual 3.2 was a disc.

Pterodaustro – The metacarpus was shorter with a larger wing finger joint. Digit 3 was not longer than digit 2.

Pterodaustro embryo – The metacarpus was relatively shorter. The unguals were relatively larger.



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