Pterosaurs on YouTube: Dave Martill 2024

In a YouTube video of over one hour
Dr Dave Martill discusses what he teaches at Portsmouth University. Click to view.

This post was thrown together quickly on topics previously covered here.

Martill is out-of-date in his remarks. Comments follow:
I often wonder why academics keep carting out those century-old etchings @ 8:48 they can verbally trash rather than presenting the audience with the latest, presumably more accurate renditions? Again @ 11:34. Problem remedied @ 17:48 and thereafter.

Since Rhamphorhynchus arose from Campylognathoides, are we sure that the oldest Rhamphorhynchus (etchesi @ 12:19) is not a transitional taxon? It’s very small. Prior studies have shown that the most basal taxa in this genus are phylogenetically miniaturized, as is often the case at the genesis of new clades throughout Tetrapoda. This hypothesis is supported by the ‘youngest’ ?Campyloganthoididae pelvis presented @ 13:15.

Re: the long cervical vertebra @ 25:05… a third clade also developed such long neck bones: Cycnorhamphidae in the form of Moganopterus. Pre-azhdarchids (not usually recognized as azhadarchids and traditionally overlooked) include JME-Sos 2428, the first flightless pterosaur, Huanhepterus from China, Ardeadactylus and Mesadactylus. All have long slender cervicals.

Re: the guesstimate of 8m-11m for a pterosaur wing @ 34:06. Let’s not forget the largest pterosaurs, all azhdarchids, were flightless. They got so big and oddly proportioned because they were flightless, as in the largest flightless birds. Looking at more complete specimens of flightless pterosaurs, like JME-Sos 2428, the azhdarchid wing is always short relative to the body and the distal wing phalages are vestiges.

Re: pterosaur hatchlings @ 36:50 and @ 37:50 … hatchlings are consistently 1/8 the size of the parent, which they resemble in proportion, as in other lepidosaurs (not archosaurs, a persistent myth). The eggs were retained within the mother until ready to hatch, as in other lepidosaurs. Also, the last day Tanis pterosaur egg/embryo is a small ctenochasmatid, the only small pterosaur known from this time. So small–medium pterosaurs were not absent. Just not collected so far.

Figure 1. Cosesaurus flapping – fast. There should be a difference in the two speeds. If not, apologies. Also, there should be some bounce in the tail and neck, but that would involve more effort and physics. ” data-image-caption=”

Figure 1. Click to enlarge and animate. Cosesaurus flapping – fast. There should be a difference in the two speeds. If not, apologies. Also, there should be some bounce in the tail and neck, but that would involve more effort and physics.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2013/04/cosesaurus-flapping800fast.gif?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2013/04/cosesaurus-flapping800fast.gif?w=584″ class=”size-full wp-image-10106″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2013/04/cosesaurus-flapping800fast.gif” alt=”Figure 1. Cosesaurus flapping – fast. There should be a difference in the two speeds. If not, apologies. Also, there should be some bounce in the tail and neck, but that would involve more effort and physics.” width=”584″ height=”261″ />

Figure 1. Click to enlarge and animate. Cosesaurus flapping – fast. There should be a difference in the two speeds. If not, apologies. Also, there should be some bounce in the tail and neck, but that would involve more effort and physics.

Re: pterosaur origins @ 38:55 … we do have a ‘lizard-grade’ animal that nests basal to pterosaurs in phylogenetic analysis: Cosesaurus from the Middle Triassic. See ResearchGate for more information. That paper came out in 2000, but pterosaur experts continue to be in denial, largely because their friend, another professor, Michael Benton, writes the textbooks they teach from. Funny how professors celebrate amateurs who find fossils, but when amateurs get published in academic journals describing long sought pterosaur ancestors their reaction is to shun this peer-reviewed and published literature. From what I hear from curators, etc, this sort of practice is not uncommon in paleontology. Remember it took more than a century for birds to be widely recognized as dinosaurs and thirty years after Ostrom’s work was published on Deinonychus. That’s just the reality, and unfortunately Dr Martill is part of the opposition to recognition.

Re: pterosaurs origins @ 39:41. Here’s the problem: preconception. Martill says ‘it is highly likely that pterosaur ancestors were arboreal animals.’ This is not true in the case of Cosesaurus and its closest relatives. It is also not true in the case of pre-birds, either. Phylogenetic analysis inevitably finds relatives for all enigma taxa. Cosesaurus is waiting for Dr Martill in Barcelona.

@39:44 The model of flitting from branch to branch is bogus, the product of wishful thinking and avoiding the literature. As in birds, flapping came first in Cosesaurus. As in bird ancestors, both were bipedal. Flapping was used as a secondary sexual behavior on running taxa that became more elaborate over the generations of competitive behavior.

Figure 3. Click to animate. The Vienna specimen of Pterodactylus (wings folded). Animation opens the wings and legs to reveal the true shape of pterosaur wings, stretched between the elbow and wingtip with a short fuselage fillet extending from elbow to mid femur. ” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/vienna-pterodactylus-721.gif?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/vienna-pterodactylus-721.gif?w=584″ class=”size-full wp-image-185″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/vienna-pterodactylus-721.gif” alt=”" width=”584″ height=”358″ />

Figure 2. Click to animate. The Vienna specimen of Pterodactylus (wings folded). Animation opens the wings and legs to reveal the true shape of pterosaur wings, stretched between the elbow and wingtip with a short fuselage fillet extending from elbow to mid femur.

@39:51 The model of pterosaurs coupling their hind limbs with their wings is the myth of the bat-wing pterosaur. No fossils with soft tissue show such wings, not even Sordes, the poster-child for this. The short-chord wing membrane, stretched between wingtip and elbow is preserved time and again without variation. That permits complete wing folding.

Figure 5. Sharovipteryx neck skin showing pycnofibers. ” data-image-caption=”

Figure 5. Sharovipteryx neck skin showing pycnofibers.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2023/06/sharovipteryx-neck588.jpg?w=226″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2023/06/sharovipteryx-neck588.jpg?w=584″ class=”size-full wp-image-79496″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2023/06/sharovipteryx-neck588.jpg” alt=”Figure 5. Sharovipteryx neck skin showing pycnofibers.” width=”584″ height=”774″ />

Figure 3. Sharovipteryx neck skin showing pycnofibers.

@41:15 pterosaur skin…pelt… fur… feathers. Also preserved in Cosesaurus, Longiquama and another bipedal relative, Sharovipteryx in abundance. These taxa are traditioally overlooked or shunned by pterosaur workers. Ask them why.

Figure 3. Several Solnhofen birds, including Archaeopteryx, compared to Ostromia to scale. ” data-image-caption=”

Figure 3. Several Solnhofen birds, including Archaeopteryx, compared to Ostromia to scale.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2017/12/archaeopteryx_specimens3.jpg?w=65″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2017/12/archaeopteryx_specimens3.jpg?w=222″ class=”size-full wp-image-29374″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2017/12/archaeopteryx_specimens3.jpg” alt=”Figure 3. Several Solnhofen birds, including Archaeopteryx, compared to Ostromia to scale.” width=”584″ height=”2698″ />

Figure 4. Several Solnhofen birds, including Archaeopteryx, compared to Ostromia to scale.

@42:32 There are 13 Solnhofen bird specimens. Martill calls them all Archaeopteryx. They are not congeneric. They already display a wide variation in sizes and morphologies.

Rhamphorhynchus entangled with Aspidorhynchus ” data-image-caption=”

Figure 1. Rhamphorhynchus entangled with Aspidorhynchus. Both complete and articulated. Inside the belly of Rhamphorhynchus are several smaller fish. Inside its throat is another. Image from Frey and Tischlinger (2012).

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/03/rhamphorhynchusfish588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/03/rhamphorhynchusfish588.jpg?w=584″ class=”size-full wp-image-5105″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/03/rhamphorhynchusfish588.jpg” alt=”Rhamphorhynchus entangled with Aspidorhynchus” width=”584″ height=”273″ />

Figure 5. Rhamphorhynchus entangled with Aspidorhynchus. Both complete and articulated. Inside the belly of Rhamphorhynchus are several smaller fish. Inside its throat is another. Image from Frey and Tischlinger (2012).

@48:15 the Aspidorhynchus [a Solnhofen fish] more likely became associated – not entangled – with the Rhamphorhynchus because the fish was drawn to the odor of the dead pterosaur rotting in the anoxic zone of the lagoon where the fish eventually quietly suffocated.

@59:48 Martill says, “the [pterosaur wing] membrane attaches to the ankle”. This is false. There are no examples of this. “they can flex the wing finger but not very much.” This is a faux pas corrected a little later by Martill. The wing finger flexes 180º for wing folding. The phalanges relax when not under tension while extended.

@ 1:02:10 pterosaurs are not ‘ornithodirans’ That myth was busted in 2000. Pterosaurs were identified as lepidosaurs arising from an earlier sister to Huehuequetzpalli in 2007. That long finger four is never found in dinosaurs or their kin. The central single sternum is also a lepidosaur trait. Metapoidial pedal phalanx 5.1 is also found in Cosesaurus and Sharovipteryx, two other bipedal lepidosaurs.

@1:02:30 pterosaur skeletons are identical to those found in flightless Cosesaurus, Sharovipteryx and Longisquama, other than wing length (converging with pre-bird theropods) so Martill’s statement about “their skeletons are so highly modified” is false.

@1:02:50 re whale origins from hippos. Again, adding taxa resolves this problem. Odontocetes are not related to Mysticetes. Google: “Triple origin of whales” to see the manuscript or google: ‘large reptile tree’ to see the cladogram.

@1:07:23 re: flapping. Flapping came first (see above) in non-volant pterosaur ancestors.