Thalassodromidae (meaning "sea runners") is a group of
azhdarchoid pterosaurs
Pterosaurs are an extinct clade of flying reptiles in the Order (biology), order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 million to 66 million years ago). Pterosau ...
from the
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
(
Albian
The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...
) of
Brazil
Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
. All known definitive members come from the
Romualdo Formation
The Romualdo Formation is a geologic Lagerstätte, Konservat-Lagerstätte in northeastern Brazil's Araripe Basin where the states of Pernambuco, Piauí and Ceará come together. The geological formation, previously designated as the Romualdo Mem ...
of
Brazil
Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
, which include the
type genus
In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name.
Zoological nomenclature
According to the International Code of Zoological Nomenclature, "The name-bearin ...
''
Thalassodromeus'', as well as ''
Tupuxuara'' and ''
Kariridraco''. Proposals of additional thalassodromid genera from the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...
are controversial and have not been supported.
The classification of Thalassodromidae is quite controversial and disputed. It was initially denominated Thalassodrominae, as a subfamily within the group
Tapejaridae. However, opposing studies regarding its placement have argued that its members were more closely related to
azhdarchids
Azhdarchidae (from the Persian language, Persian word , , a dragon-like creature in Persian mythology) is a family (biology), family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azh ...
and
dsungaripterids, while also elevating it to family level. Though the relationship with tapejarids remains supported by many studies, it has been proposed that it is preferable to retain them as a distinct family for consistency of communication.
Classification
The classification of thalassodromids is controversial. Its initial members included ''
Thalassodromeus'' and ''
Tupuxuara'', which were assigned initially to the family
Tapejaridae by Brazilian paleontologists
Alexander Kellner
Alexander Wilhelm Armin Kellner (born September 26, 1961) is a Brazilian geologist and paleontologist who is a leading expert in the field of studying pterosaurs. His research has focused mainly on fossil reptiles from the Cretaceous Period, i ...
and Diógenes de Almeida Campos. In 2007, the subfamily Thalassodrominae was coined by Kellner to group both members within Tapejaridae.
However, a conflicting phylogenetic model emerged arguing that both ''Thalassodromeus'' and ''Tupuxuara'' were more closely related to the family
Azhdarchidae
Azhdarchidae (from the Persian word , , a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cre ...
instead of the tapejarids. As early as 2003, paleontologist David Unwin created the group
Neoazhdarchia to contain ''Tupuxuara'' and Azhdarchidae. This arrangement would later be supported by British paleontologists