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Re: Sauropod-eating snakes



But would any Cretaceous snake coil itself around live prey to suffocate it, prior to swallowing? Madtsoiids like _Sanajeh_ were narrow-gaped snakes. The authors of the _Sanajeh_ paper suggest that titanosaur eggs had to be crushed by constriction before swallowing. I assume that small prey items (like titanosaur hatchlings!) were eaten alive. AFAIK, there are no known wide-gaped (macrostomatous) snakes in the Cretaceous. So no Cretaceous snakes were capable of swallowing very large prey, in the manner of a boa constrictor (for example).


The phylogeny in the _Sanajeh_ paper recovers the pachyophiids as sister taxon to the macrostomatous snakes. This would drag the origin of the wide-gaped snakes back to the mid-Cretaceous, suggesting that macrostomatous snakes were around in the later Cretaceous. But the phylogenetic relationships of pachyophiids are controversial. Pachyophiids like _Pachyrhachis_ retain fairly well- developed hindlimbs, and some phylogenetic analyses place them outside the crown-group, as very primitive snakes.

Great questions - I suppose one point worth noting is that "narrow gape" is somewhat relative. While madtsoiids were relatively narrow gaped, they did still have relatively kinetic skulls by most standards. No macrostomatan style swallowing going on, but animals like varanids and gekkonids swallow pretty darn big stuff when opportunity allows. I suppose what we really need here is a mechanical analysis of the actual maximum gape in Sanajeh - should be a plausible thing to do (perhaps already done?)

--Mike


Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
mhabib@chatham.edu
(443) 280-0181