| Thanatosdrakon | |
|---|---|
 | |
| Reconstructed skeleton (left) in standing posture | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | †Pterosauria |
| Suborder: | †Pterodactyloidea |
| Clade: | †Azhdarchoidea |
| Family: | †Azhdarchidae |
| Clade: | †Quetzalcoatlini |
| Genus: | †Thanatosdrakon Ortiz David et al.,2022 |
| Species: | †T. amaru |
| Binomial name | |
| †Thanatosdrakon amaru Ortiz David et al., 2022 | |
Thanatosdrakon is a genus ofazhdarchidpterosaur that lived during theConiacian andSantonian ages of theLate Cretaceous period in what is now Argentina, around 89.6 and 86.3 million years ago. Its remains were found in thePlottier Formation of theNeuquén Basin in theMendoza Province. The genus only consists of thetype species,Thanatosdrakon amaru, named and described by paleontologists Leonardo Ortiz David, Bernardo González Riga, andAlexander Kellner. Its generic name means "dragon of death" in Greek, while itsspecific name is aQuechuan word meaning "flying serpent" and refers to the Incan deityAmaru.Thanatosdrakon is known from two specimens, theholotype, consisting of a partialpostcranial skeleton, and theparatype, consisting of a lefthumerus. The holotype includes material that is previously undescribed in giant azhdarchid pterosaurs.
Thanatosdrakon was a giant pterosaur. The holotype specimen is estimated to have had awingspan of around 7 m (23 ft), while the paratype has been given an even larger wingspan estimate at around 9 m (30 ft), makingThanatosdrakon the largest known pterosaur from South America. In its description,Thanatosdrakon was assigned to the subfamily Quetzalcoatlinae within the family Azhdarchidae, closely related to bothQuetzalcoatlus andCryodrakon.Thanatosdrakon coexisted with a wide range of dinosaur and non-dinosaurtaxa, as demonstrated by the diverse and abundant fossil remains found in the Plottier Formation.
The fossil remains ofThanatosdrakon were uncovered in the uppermostPlottier Formation of theNeuquén Basin, located in the province ofMendoza, Argentina, within theAndean Mountain Range. The rock formation dates to the upperConiacian and lowerSantonian of theLate Cretaceous period, around 89.6 to 86.3 million years ago.[1] The remains include two well-preserved specimens that were first described back in 2018.[2] In 2022, these fossil remains were given a newgenus andtype species,Thanatosdrakon amaru, named and described by Brazilian paleontologists Leonardo Ortiz David,Bernardo González Riga, andAlexander Kellner. The generic nameThanatosdrakon is derived from the Greek words θάνατος (thanatos, meaning "death") and δράκων (drakon, meaning "dragon"), and is translated as "dragon of death". Thespecific nameamaru is aQuechuan word that means "flying serpent" and refers to theIncan deityAmaru.[1]
The two known specimens ofThanatosdrakon are theholotype and theparatype, which consist of several well-preservedaxial andappendicular bones. The holotype ofThanatosdrakon, specimen UNCUYO-LD 307, consists of a partialpostcranial skeleton with around thirty bones, while the paratype, specimen UNCUYO-LD 350, is a complete lefthumerus. The holotype includes material that has never been previously described in giantazhdarchidpterosaurs, such as a completenotarium, dorsosacral vertebrae and acaudal vertebra. Due to the age of its fossils,Thanatosdrakon is so far the oldest known member of itsclade, Quetzalcoatlinae, a subgroup within the larger Azhdarchidae. The discovery ofThanatosdrakon has led to a better understanding of the anatomy andphylogeny of azhdarchids due to its more complete and well-preserved remains, in contrast to the fragmentary and scarce fossils that are usually found in azhdarchidtaxa.[1][3]
Thanatosdrakon was an enormous pterosaur, with its humerus alone, paratype specimen UNCUYO-LD 350, measuring 45 cm (1 ft 6 in).[2] The holotype ofThanatosdrakon, specimen UNCUYO-LD 307, belongs to either a juvenile or a subadult individual. In its description, Ortiz David and colleagues estimated awingspan of approximately 7 m (23 ft) for the holotype, while a wingspan of approximately 9 m (30 ft) has been estimated for the paratype. These measurements would makeThanatosdrakon the largest known pterosaur from South America. Its axial and appendicular bones are represented and preserved in three dimensions.[1][4]
In its description in 2022, Ortiz David and colleagues performed aphylogenetic analysis in which they recoveredThanatosdrakon in the subfamily Quetzalcoatlinae within the family Azhdarchidae. Within Quetzalcoatlinae, they recovered two well-defined clades. The first one consists of the pterosaursArambourgiania,Mistralazhdarcho,Aerotitan,Hatzegopteryx, andAlbadraco, while the second one consists ofCryodrakon,Quetzalcoatlus, andThanatosdrakon itself. In this second quetzalcoatline clade,Thanatosdrakon is more specifically recovered as thesister taxon ofQuetzalcoatlus. Thecladogram below shows the results of the analysis by Ortiz David and colleagues.[1]
Thanatosdrakon is known from the uppermost levels of the Plottier Formation, which represents a floodplain withephemeral rivers and consists ofmudstone,siltstone,claystone andsandstone, suggesting it lived in acontinental environment created by thelow-gradient wandering rivers that laid downalluvial deposits across the formation.[1]
In the Plottier Formation,Thanatosdrakon was contemporaneous with an indeterminateabelisaurid,[5] basalcoelurosaurian,unenlagiine,aeolosaurin,saltasaurid, andornithopod,[6] as well as thelithostrotiantitanosaursAntarctosaurus giganteus,[7]Notocolossus,[8] andPetrobrasaurus.[9][6] Non-dinosaur taxa from the formation includefreshwaterbivalves, an indeterminatecrocodyliforme andmesoeucrocodylian,[6] thechelid turtlesLinderochelys[10] andRionegrochelys,[11] and at least one indeterminatemammal.Ichnotaxa consist of the burrowichnogenusScoyenia sp., and insectichnogenusTaenidium sp.[6]
