New AMNH Exhibit on Pterosaurs – Outdated before it opens

Figure 1. Click to play. AMNH pterosaur exhibit video featuring Mark Norell, Alex Kellner and Mike Habib.

Figure 1. Click to play. AMNH pterosaur exhibit video featuring Mark Norell, Alex Kellner and Mike Habib. Please don’t tell me those pteroids and fingers are pointing forward! Gaak!

The American Museum of Natural History
(AMNH) is putting on a pterosaur exhibit: “Pterosaurs, Flight in the Age of Dinosaurs,” April 5 to January 4, 2015. Mark Norrell, curator and chair of the Paleontology Division and Alex Kellner of the Museu Nacional, Rio de Janiero (and a former AMNH staff member) oversee the exhibit. Here‘s the website.

Sadly the exhibit is behind the times.
Here (Fig. 1) is a sample of outdated art from their exhibit with corrections added.

Figure 1. Dawndraco kanzai (formerly Pteranodon) was redescribed by Kellner, hence its inclusion in the exhibit. Wing membranes to the ankles echoes the famous AMNH display, but no pterosaur has this. Rather the wings were stretched between elbow and wing finger with a fuselage fillet to the thigh. And the hind limbs extended like horizontal stabilizers behind the wings.

Figure 1. Dawndraco kanzai (formerly Pteranodon) was redescribed by Kellner, hence its inclusion in the exhibit. Wing membranes to the ankles echoes the famous AMNH display, but no pterosaur has this morphology and configuration. Rather the wings were stretched between elbow and wing finger with a fuselage fillet to the thigh. And the hind limbs extended like horizontal stabilizers behind the wings.

When a museum opens a new exhibit
it should come with outstanding news. Unfortunately this is a celebration of the way pterosaurs have been misinterpreted with no happy ending.

Their Dimorphodon (Fig. 2) contains several errors. Pedal digit 5 never framed the uropatagium. Rather it enabled perching, acting like a universal wrench, as shown here.

Figure 2.Above: AMNH art for Dimorphodon. Below: from reptile evolution.com. Corrections noted.

Figure 2.Above: AMNH art for Dimorphodon. Below: from reptile evolution.com. Corrections noted.

The AMNH answers: What is a pterosaur?
From the AMNH website: “Neither birds nor bats, pterosaurs were reptiles, close cousins of dinosaurs who evolved on a separate branch of the reptile family tree. They were also the first animals after insects to evolve powered flight—not just leaping or gliding, but flapping their wings to generate lift and travel through the air. They evolved into dozens of species. Some were as large as an F-16 fighter jet, and others as small as a paper airplane.  Scientists have long debated where pterosaurs fit on the evolutionary tree. The leading theory today is that pterosaurs, dinosaurs, and crocodiles are closely related and belong to a group known as archosaurs.”

Sadly we know the “leading theory” cannot be supported. The actual ancestors have been known since 2001, but ignored.

Figure 3. According to the AMNH, Scleromochlus is "one of the closest early cousins of pterosaurs." Oddly, they gave it the skull of Longisquama. Note the vestigial hands. These cannot elongate to become wings and pedal digit 5 is a vestige that cannot elongate to match basal pterosaurs.

Figure 3. Click to enlarge. According to the AMNH, Scleromochlus is “one of the closest early cousins of pterosaurs.” Oddly, they gave it the skull of Longisquama. Note the vestigial hands. These cannot elongate to become the hyper-elongate wings and the pedal digit 5 is a vestige that cannot elongate to match the hyper-elongate lateral pedal digit of basal pterosaurs.

Scleromochlus a closest cousin?
The AMNH reported Scleromochlus (Fig. 3) was “one of the closest early cousins of pterosaurs,” ignoring the readily observable fact that the hands were vestiges and so was pedal digit 5, which is actually absent in Scleromochlus and its kin. Oddly, they gave it the skull of Longisquama (Fig. 4), an actual pterosaur cousin. Actually pterosaurs descend from fenestrasaurs like Cosesaurus, Sharovipteryx and Longisquama (Fig. 4).

Squamates, tritosaurs and fenestrasaurs in the phylogenetic lineage preceding the origin of the Pterosauria.

Figure 5. Click to enlarge. Lepidosaurs, tritosaurs and fenestrasaurs in the phylogenetic lineage preceding the origin of the Pterosauria. Note all these taxa have a long manual digit 4 and an long pedal digit 5, traits you won’t find in archosaurs. There’s also a sternum, a stem-like coracoid, a deltopectoral crest an attenuated tail and every other trait it takes to make a pterosaur. And, oh, yes, soft tissue for membrane formation!!!

The AMNH devotion to inaccuracy
also includes their version of Rhamphorhynchus (Fig. 6) with wings too short, feet too small and belly not deep enough.

Figure 6. The AMNH Rhamphorhynchus with errors noted alongside a more accurate rendition.

Figure 6. The AMNH Rhamphorhynchus with errors noted alongside a more accurate rendition of the dark wing specimen

Hopefully,
someday museums will devote their displays to accurate renditions that actually teach the public something valid about pterosaurs. It’s embarrassing to see them hold on to such outmoded phylogenies and inaccurate representations.

If you think I’m wrong, please go see the specimens and repeat the analyses.That’s good Science. Repeatability.

 

 

 

 

 

 

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