In 2002, during an expedition to the coal mines of Cerrejón in La Guajira[1] launched by the University of Florida and Smithsonian Tropical Research Institute,[2] large thoracic vertebrae and ribs were unearthed by the students Jonathon Bloch and Carlos Jaramillo.

[5] These were found in association with other giant reptile fossils of turtles and crocodilians from the Cerrejón Formation, dating to the mid-late Paleocene epoch (around 60-58 mya), a period just after the Cretaceous–Paleogene extinction event.

[6] The fossils were then transported to the Florida Museum of Natural History, where they were studied and described by an international team of Canadian, American, and Panamanian scientists in 2009 led by Jason J.

These estimates far exceed the largest modern snakes, the green anaconda and the reticulated python, as well as the previous record holder, the madtsoid Gigantophis.

[12] The cladogram below follows the 2015 phylogenetic analysis:[12] Candoia Erycinae Titanoboa Boa Corallus priscus extant Corallus Chilabothrus Epicrates Eunectes stirtoni extant Eunectes Initially, Titanoboa was thought to have acted much like a modern anaconda based on its size and the environment it lived in, with researchers suggesting that it may have fed on the local crocodylomorph fauna.

[7] Due to the warm and humid greenhouse climate of the Paleocene, the region of what is now Cerrejón was a coastal plain covered by wet tropical forests with large river systems, which were inhabited by various freshwater animals.

The genera that coexisted alongside Titanoboa included the large, slender-snouted Acherontisuchus, the medium-sized but broad-headed Anthracosuchus, and the relatively small Cerrejonisuchus.

[17][18] Turtles also thrived in the tropical wetlands of Paleocene Colombia, giving rise to several species of considerable size such as Cerrejonemys[19] and Carbonemys.

Although it is possible that this low diversity was a result of the wetland nature of the depositional environment, samples from other localities in the same time frame suggest that all of the forests that arose shortly following the Cretaceous-Paleogene mass extinction were of similar composition.

Following this correlation, the authors suggest that the mean annual temperature can be calculated by comparing the maximum body size of poikilotherm animals found in two localities.

J. M. Kale Sniderman used the same methodology as Head and colleagues on the Pleistocene monitor lizard Varanus priscus, comparing it to the extant Komodo dragon.

In conclusion it is argued that Paleocene rainforests may not have been any hotter than those today and that the massive size of Titanoboa and Varanus priscus may instead be the result of lacking significant mammalian competition.

[27] Mark W. Denny, Brent L. Lockwood and George N. Somero also disagreed with Head's conclusion, noting that although this method is applicable to smaller poikilotherms, it is not constant across all size ranges.

As thermal equilibrium is achieved through the relation between volume and surface area, they argue that the large size of Titanoboa coupled with the high temperatures proposed by Head et al. would mean that the animal would overheat easily if resting in a coiled up state.

Varying posture could help cool down if needed, basking behavior or heat absorption through the substrate are both unknown and the potentially semi-aquatic nature of the animal creates additional factors to consider.

Ultimately, Denny and colleagues argue that the nature of the giant snake renders it a poor indicator for the climate of the Paleocene and that the mean annual temperature must have been 4 to 6 °C (39 to 43 °F) cooler than the current estimate.

[28] These issues, alongside adjustments suggested by Makarieva, were addressed by Head and his team the same year, arguing that Denny and colleagues misunderstand their proposed model.

For one, Head argues, Komodo dragons are a poor analogy as they are geographically restricted to the islands of Indonesia, limiting the size they could grow to while both green anacondas and Titanoboa are mainland animals.