“Crocodiles can’t fly. Birds can. Scientists have finally figured out why”

OMG
has the drive for publicity about esoteric paleo papers reached this level? Apparently so.

If you’re looking for the answer to the above click-bait headline, ripped from the online publicity (see below), relax. It goes unanswered in the text.

From the Seymour et al 2026 Abstract
“The origin and evolution of endothermy among Archosauria are uncertain because living species are represented by two lineages: ectothermic crocodylians (Pseudosuchia) and endothermic birds (Avemetatarsalia).”

Remember that keyword: ‘Avemetatarsalia’ (see below).
Nevermind (for now) that in the LRT Archosauria includes only crocs + dinos.

“Endothermy is characterized by high metabolic rates (tachymetabolism) and a physiological ability to control body temperature (thermoregulation), partly by using heat generated within the body. Ectothermy is characterized by low metabolic rates (bradymetabolism) and behavioral body temperature regulation. Levels of metabolic rate can be indirectly assessed by measuring the size of primary nutrient foramina of long bones.”

“Avemetatarsalians apparently remained endothermic until the present, while some tachymetabolic pseudosuchians became bradymetabolic relatively recently, as evident in extant crown crocodylians.”

No mention of the other flying vertebrates, bats and pterosaurs, in the text of this paper. This is especially odd in the case of pterosaurs, which are supposed to be basal Avemetarsalians in academic circles, but are recovered as tiny tanystropheid lepidosaurs in the LRT.

No mention of the basal bipedal crocodylomorphs (Scleromochlus, Gracilisuchus, Dibrothosuchus, Pseudoshesperosuchus, Lewisuchus, Terrestrisuchus, Litargosuchus Fig 2).

No Turfanosuchus. No Poposaurus. No Sillesaurus. No Lagerpeton.
All were bipeds in the manner of basal theropods. Silesaurus and Lagerpeton have been in the news lately as close to dinos or close to pteros.

Figure 2. Litargosuchus with skull enlarged in 3 views. The Yonghesuchus skull is slightly larger than this one. ” data-image-caption=”

Figure 2. Litargosuchus with skull enlarged in 3 views. The Yonghesuchus skull is slightly larger than this one.

” data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2020/03/litargosuchus588.jpg?w=584″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2020/03/litargosuchus588.jpg?w=584″ alt=”Figure 2. Litargosuchus with skull enlarged in 3 views. The Yonghesuchus skull is slightly larger than this one.” class=”wp-image-43818″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2020/03/litargosuchus588.jpg?w=584 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2020/03/litargosuchus588.jpg?w=136 136w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2020/03/litargosuchus588.jpg?w=272 272w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2020/03/litargosuchus588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />

There are so many other problems waiting to be resolved
by paleontologists. I wonder what are they going to do now that this project is over.

References
Seymour RS et all (11 co-authors) 2026. Blood flow rates to long bones of archosaurs reveal high aerobic metabolic rates and endothermy throughout most of their evolutionary history. Paleobiology , First View , pp. 1 – 13 DOI: https://doi.org/10.1017/pab.2026.10110

Raise your hand if you harbor a secret desire to be the 13th co-author of this study.
IMHO, this study is something called, ‘make-work‘.

Lead author Roger Seymour, Adelaide University (South Australia), reported, “At the moment I am trying to study the physiology and pollination biology of heat-producing flowers, gas exchange in diving insects and structure and function of the vertebrate cardiovascular system, all with allometric principles.”

Publicity
phys.org/news

“Crocodiles can’t fly. Birds can. Scientists have finally figured out why”

“So modern crocodiles have a warm-blooded-style heart but produce the low blood-flow rates and pressures we would expect for their cold-blooded nature. This suggests their hearts once evolved for warm-blooded life. Because warm-bloodedness is associated with high rates of blood flow, we searched for fossil evidence of large blood vessels to accommodate high flow.’

“Our new study of hole size in fossil leg bones focused on the earliest archosaur relatives from both lineages we could find. Starting in 2018, we assembled data from 81 species, which showed that both the crocodile and dinosaur-bird lineages had high metabolic rates until relatively recently—perhaps around 66 million years ago, when most dinosaurs died out—when crocodiles abandoned it in favor of a cold-blooded metabolism.”

“The new view of the history of the crocodile lineage starts in the Triassic period, with them as active, land-dwelling, warm-blooded animals, in many cases even running on two legs. They apparently remained warm-blooded until recently.”

If this is NOT the old view among academics,
it is the old view in the large reptile tree (LRT, 2340 taxa, Fig 2).

“Why did their metabolisms slow down? We think it may have been related to their current behavior as ambush predators in water.”

The other possibility is all other crocs died out for various reasons at various times, leaving a few bradymetabolic ambush predators.
But that doesn’t explain the extinction of other bradymetabolic gators.