Tropeognathus Robustus
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''Tropeognathus'' (meaning "
keel The keel is the bottom-most longitudinal structural element of a watercraft, important for stability. On some sailboats, it may have a fluid dynamics, hydrodynamic and counterbalancing purpose as well. The keel laying, laying of the keel is often ...
jaw") is a
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of large
pterosaur Pterosaurs are an extinct clade of flying reptiles in the 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). Pterosaurs are the earli ...
s from the late
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 ...
of
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
. This genus is considered to be a member of the family
Anhangueridae Anhangueridae (alternatively called Ornithocheiridae, meaning "bird hands") is a group of pterosaurs within the suborder Pterodactyloidea. These pterosaurs were among the last to possess teeth. Members that belong to this group lived from the ...
, however, several studies have also recovered it within another family called
Ornithocheiridae Anhangueridae (alternatively called Ornithocheiridae, meaning "bird hands") is a group of pterosaurs within the suborder Pterodactyloidea. These pterosaurs were among the last to possess teeth. Members that belong to this group lived from the E ...
. Both of these families are diverse groups of pterosaurs known for their keel-tipped snouts and large size. ''Tropeognathus'' is regarded as the largest pterosaur found in the Southern Hemisphere, only rivaled by the huge
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 ...
. The type and only species is ''Tropeognathus mesembrinus''. Fossil remains of ''Tropeognathus'' have been recovered 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 ...
, which is a
Lagerstätte A Fossil-Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that preserves an exceptionally high amount of palaeontological information. ''Konzentrat-Lagerstätten'' preserv ...
located in the
Santana Group The Santana Group is a geologic group, formerly included as the middle part of the Araripe Group, in the Araripe Basin of northeastern Brazil. The group comprises the Crato, Ipubi and Romualdo Formations and is dated to the Aptian to Albian stag ...
of the
Araripe Basin The Araripe Basin () is a rift basin covering about ,Neto et al., 2013, p.1 in Ceará, Piauí and Pernambuco states of northeastern Brazil. It is bounded by the Patos and Pernambuco lineaments, and is situated east of the Parnaíba Basin, south ...
in northeastern
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 ...
.


Discovery and naming

In the 1980s the German
paleontology Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure ge ...
museum '' Bayerische Staatssammlung für Paläontologie und historische Geologie'' in
Munich Munich is the capital and most populous city of Bavaria, Germany. As of 30 November 2024, its population was 1,604,384, making it the third-largest city in Germany after Berlin and Hamburg. Munich is the largest city in Germany that is no ...
acquired a pterosaur skull from Brazilian fossil dealers that had probably been found in
Ceará Ceará (, ) is one of the 26 states of Brazil, located in the Northeast Region, Brazil, northeastern part of the country, on the Atlantic Ocean, Atlantic coast. It is the List of Brazilian states by population, eighth-largest Brazilian State by ...
, in the geological group called the
Santana Group The Santana Group is a geologic group, formerly included as the middle part of the Araripe Group, in the Araripe Basin of northeastern Brazil. The group comprises the Crato, Ipubi and Romualdo Formations and is dated to the Aptian to Albian stag ...
, which is located in the Araripe Basin (
Chapada do Araripe The Chapada do Araripe, also known as the Serra do Araripe, is a ''chapada'' (plateau) in northeastern Brazil. The chapada forms the boundary of Ceará and Pernambuco states, and forms the watershed between the Jaguaribe River of Ceará, which flo ...
) of Brazil. In 1987, it was named and described as the
type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
''Tropeognathus mesembrinus'' by
Peter Wellnhofer Peter Wellnhofer (born Munich, 1936) is a German paleontologist at the Bayerische Staatssammlung fur Paläontologie in Munich. He is best known for his work on the various fossil specimens of ''Archaeopteryx'' or "Urvogel", the first known bird. ...
. The generic name is derived from Greek τρόπις, ''tropis'', "keel", and γνάθος, ''gnathos'', "jaw". The
specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...
is derived from
Koine Koine Greek (, ), also variously known as Hellenistic Greek, common Attic, the Alexandrian dialect, Biblical Greek, Septuagint Greek or New Testament Greek, was the common supra-regional form of Greek spoken and written during the Hellenistic ...
''mesembrinos'', "of the noontide", simplied as "southern", in reference to the provenance from the Southern hemisphere.Peter Wellnhofer, 1987, "New crested pterosaurs from the Lower Cretaceous of Brazil", ''Mitteilungen der Bayerische Staatssammlung für Paläontologie und historische Geologie'' 27: 175–186; Muenchen The
holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
, BSP 1987 I 46, was discovered in a layer of 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 ...
within the Santana Group, dating to the latest
Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...
and earliest
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 ...
stages. Along with the holotype, several other pterosaur specimens were found in the fossil site, these specimens however, were referred to genera such as '' Anhanguera'' and ''
Cearadactylus ''Cearadactylus'' is a genus of large anhanguerid pterodactyloid pterosaur from the Romualdo Formation of Brazil, South America. Fossil remains of ''Cearadactylus'' dated back to the Albian stage of the Early Cretaceous period, about 112 million ...
''.Leonardi, G. & Borgomanero, G. (1985). "''Cearadactylus atrox'' nov. gen., nov. sp.: novo Pterosauria (Pterodactyloidea) da Chapada do Araripe, Ceara, Brasil." ''Resumos dos communicaçoes VIII Congresso bras. de Paleontologia e Stratigrafia'', 27: 75–80. The uncovered holotype consists of a skull with lower jaws. A second specimen was referred by André Jacques Veldmeijer in 2002: SMNS 56994, which consists of a partial
mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...
. In 2013, Brazilian paleontologist
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 ...
referred a third, larger, specimen: MN 6594-1, a skeleton with skull, with extensive elements of all body parts, except the tail and the lower hindlimbs. After ''Tropeognathus mesembrinus'' was named by Peter Wellnhofer in 1987, other researchers tended to consider it part of several other genera, leading to an enormous taxonomic confusion.Wellnhofer, P. (1991). ''The Illustrated Encyclopedia of Pterosaurs''. New York: Barnes and Noble Books. pp. 124. . It was considered an ''Anhanguera mesembrinus'' by Alexander Kellner in 1989, a ''
Criorhynchus ''Ornithocheirus'' (from Ancient Greek "ὄρνις", meaning bird, and "χεῖρ", meaning hand) is a pterosaur genus known from fragmentary fossil remains uncovered from sediments in the United Kingdom and possibly Morocco. Several species ha ...
mesembrinus'' by Veldmeijer in 1998 and a ''
Coloborhynchus ''Coloborhynchus'' is a genus of pterodactyloid pterosaur belonging to the family Anhangueridae, though it has also been recovered as a member of the Ornithocheiridae in some studies. ''Coloborhynchus'' is known from the Lower Cretaceous of Engla ...
mesembrinus'' by Michael Fastnacht in 2001. Later the same year,
David Unwin David (; , "beloved one") was a king of ancient Israel and Judah and the third king of the United Monarchy, according to the Hebrew Bible and Old Testament. The Tel Dan stele, an Aramaic-inscribed stone erected by a king of Aram-Damas ...
referred the ''Tropeognathus'' material to ''
Ornithocheirus ''Ornithocheirus'' (from Ancient Greek "ὄρνις", meaning bird, and "χεῖρ", meaning hand) is a pterosaur genus known from fragmentary fossil remains uncovered from sediments in the United Kingdom and possibly Morocco. Several species ha ...
simus'', making ''Tropeognathus mesembrinus'' a junior synonym, though he had reinstated a ''Ornithocheirus mesembrinus'' in 2003. In 2006, Veldmeijer accepted that ''Tropeognathus'' and ''Ornithocheirus'' were cogeneric, but rejected ''O. simus'' as the type species of ''Ornithocheirus'' in favor of ''O. compressirostris'', which was named as ''
Lonchodectes ''Lonchodectes'' (meaning "lance biter") was a genus of lonchodectid pterosaur from several formations dating to the Turonian (Late Cretaceous) of England, mostly in the area around Kent. The species belonging to it had been assigned to ''Orni ...
'' by Unwin due to an analysis by English paleontologist
Reginald Walter Hooley Reginald Walter Hooley (5 September 1865 – 5 May 1923) was a businessman and amateur paleontologist, collecting on the Isle of Wight. He is probably best remembered for describing the dinosaur ''Iguanodon atherfieldensis'', now ''Mantellisaurus ...
in 1914. This made Veldmeijer use the names ''Criorhynchus simus'' and ''Criorhynchus mesembrinus'' instead. In 2013 however, Taissa Rodrigues and Alexander Kellner concluded ''Tropeognathus'' to be valid, and containing only ''T. mesembrinus'', the type species. Back in 1987, Wellnhofer had named a second species called ''Tropeognathus robustus'', based on specimen BSP 1987 I 47, which is a more robust lower jaw. In 2013 however, ''T. robustus'' was considered as a species of ''Anhanguera'', resulting in an ''Anhanguera robustus''.


Description


Size

''Tropeognathus'' is known to have reached
wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingsp ...
s of about , as can be inferred from the impressive size of the specimen MN 6594-V, identified as ''Tropeognathus''
cf. The abbreviation cf. (short for either Latin or , both meaning 'compare') is generally used in writing to refer the reader to other material to make a comparison with the topic being discussed. However some sources offer differing or even contr ...
''T. mesembrinus''. The maximum wingspan estimate for ''Tropeognathus'' reaches , making it slightly larger than the average estimate for the genus, though much larger than other close relatives such as ''Ornithocheirus'' and ''Coloborhynchus'', which are typically estimated to be between . A skull unearthed belonging to the related ''Coloborhynchus'' likely measured , which led to a wingspan estimate of respectively: larger than the average estimates for this genus, but still shorter than that of ''Tropeognathus''. This specimen however, was concluded to belong to another genera, though in several studies, some paleontologists consider it under the species ''Coloborhynchus capito'', which was originally called ''Ornithocheirus capito'' by the British paleontologist
Harry Govier Seeley Harry Govier Seeley (18 February 1839 – 8 January 1909) was a British paleontologist. Early life Seeley was born in London on 18 February 1839, the second son of Richard Hovill Seeley, a goldsmith, and his second wife Mary Govier. When his fa ...
back in 1870.Martill, D.M. and Unwin, D.M. (2011). "The world's largest toothed pterosaur, NHMUK R481, an incomplete rostrum of ''Coloborhynchus capito'' (Seeley 1870) from the Cambridge Greensand of England." ''Cretaceous Research'', (advance online publication). Seeley, H.G. (1870). ''The Ornithosauria: an Elementary Study of the Bones of Pterodactyles''. Cambridge, 130 pp.


Skull and crests

The skull of ''Tropeognathus'' bore a distinctively convex, "keeled" crests on the lower end of its snout, with an opposing, smaller mass on the underside of the lower jaws. This structure was prominent, well-developed, and relatively large in ''Tropeognathus'' (especially in males); however, by comparison, these crests were somewhat weakly-formed as opposed to the thicker skull crests of other pterosaurs, such as ''Ornithocheirus''.Veldmeijer, A.J. (2006).
Toothed pterosaurs from the Santana Formation (Cretaceous; Aptian-Albian) of northeastern Brazil. A reappraisal on the basis of newly described material
." Tekst. – Proefschrift Universiteit Utrecht.
The upper crests arose from the snout tip and extended back to the ''fenestra nasoantorbitalis'', the large opening in the skull side. An additional, smaller crest projected down from the lower jaws at their
symphysis A symphysis (, : symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing together o ...
("chin" area). The similar
anhanguerid Anhangueridae (alternatively called Ornithocheiridae, meaning "bird hands") is a group of pterosaurs within the suborder Pterodactyloidea. These pterosaurs were among the last to possess teeth. Members that belong to this group lived from the ...
''Anhanguera'' possessed jaws that were tapered in width, but expanded into a broad, spoon-shaped rosette at the tip, which differed from ''Tropeognathus'' for having a narrower appearance.Kellner, A.W.A. and Tomida, Y. (2000). "Description of a new species of ''Anhanguera'' (Pterodactyloidea) with comments on the pterosaur fauna from the Santana Formation (Aptian–Albian), northeastern Brazil." Tokyo, National Science Museum (''National Science Museum Monographs'', 17). The jaws can be distinguished from its relatives by a few differences in the crest: unlike its close relatives ''Coloborhynchus'' and ''Ornithocheirus'', the crest on the upper jaw of ''Tropeognathus'' was more prominent and much larger, and therefore resulting in a broader skull.


Vertebrae

The first five dorsal vertebrae of ''Tropeognathus'' are fused into a
notarium Notarium or os dorsale is a bone consisting of the fused vertebra of the shoulder in birds and some pterosaurs. The structure helps brace the chest against the forces generated by the wings. In birds, the vertebrae are only in contact with adjac ...
, with five sacral vertebrae fused into a
synsacrum The synsacrum is a skeletal structure of birds and other dinosaurs, pterosaurs, as well as xenarthran mammals, in which the sacrum is extended by incorporation of additional fused or partially fused caudal or lumbar In tetrapod anatomy, lum ...
, and the third and fourth sacral vertebrae are keeled within. The front blade of the ilium is strongly directed upwards, resulting in a narrow structure.


Classification

In 1987, Wellnhofer assigned ''Tropeognathus'' to a Tropeognathidae. This concept was not adopted by other workers; several researchers place ''Tropeognathus mesembrinus'' in the Anhangueridae, along with ''Anhanguera'', while other cladistic analyses place ''Tropeognathus'' within the Ornithocheiridae as a basal member, meaning that it was more closely related to ''Ornithocheirus'' than ''Anhanguera''. This concept is mostly used by the European colleagues, who prefer to use the Ornithocheiridae as the most inclusive group rather than the Anhangueridae. A topology made by Andres and Myers in 2013 placed ''Tropeognathus'' within the family Ornithocheiridae in a more basal position than ''Ornithocheirus'', and the family itself is placed within the more inclusive clade
Ornithocheirae Ornithocheiromorpha (from Ancient Greek, meaning "bird hand form") is a group of pterosaurs within the suborder Pterodactyloidea. Fossil remains of this group date back from the Early Cretaceous, Early to Late Cretaceous Period (geology), period ...
. However, many subsequent analyses made in 2019 and 2020 have recovered ''Tropeognathus'' within the family Anhangueridae,Borja Holgado, Rodrigo V. Pêgas, José Ignacio Canudo, Josep Fortuny, Taissa Rodrigues, Julio Company & Alexander W.A. Kellner, 2019, "On a new crested pterodactyloid from the Early Cretaceous of the Iberian Peninsula and the radiation of the clade Anhangueria", ''Scientific Reports'' 9: 4940 Pêgas, R.V., Holgado, B., Leal, M.E.C., 2019. "''Targaryendraco wiedenrothi'' gen. nov. (Pterodactyloidea, Pteranodontoidea, Lanceodontia) and recognition of a new cosmopolitan lineage of Cretaceous toothed pterodactyloids", ''Historical Biology'', 1–15. doi:10.1080/08912963.2019.1690482 with a specific one by Borja Holgado and Rodrigo Pêgas in 2020, placing ''Tropeognathus'' more specifically within the subfamily
Tropeognathinae Anhangueridae (alternatively called Ornithocheiridae, meaning "bird hands") is a group of pterosaurs within the suborder Pterodactyloidea. These pterosaurs were among the last to possess teeth. Members that belong to this group lived from the E ...
, sister taxon to ''
Siroccopteryx ''Siroccopteryx'' is an extinct genus of anhanguerid pterodactyloid pterosaur which lived in Morocco during the Cenomanian stage of the Late Cretaceous. Some researchers, such as David M. Unwin, consider the genus a junior synonym of '' Colobor ...
''. Topology 1: Andres & Myers (2013). Topology 2: Holgado & Pêgas (2020).


In popular culture

''Tropeognathus mesembrinus'' was the subject of an entire episode of the award-winning
BBC The British Broadcasting Corporation (BBC) is a British public service broadcaster headquartered at Broadcasting House in London, England. Originally established in 1922 as the British Broadcasting Company, it evolved into its current sta ...
television program ''
Walking with Dinosaurs ''Walking with Dinosaurs'' is a 1999 six-part nature documentary television miniseries created by Tim Haines and produced by the BBC Science Unit, the Discovery Channel and BBC Worldwide, in association with TV Asahi, ProSieben and France 3. ...
'' (which used the first name of its cousin ''
Ornithocheirus ''Ornithocheirus'' (from Ancient Greek "ὄρνις", meaning bird, and "χεῖρ", meaning hand) is a pterosaur genus known from fragmentary fossil remains uncovered from sediments in the United Kingdom and possibly Morocco. Several species ha ...
'' but was incorrectly named as a species of it, as ''Ornithocheirus mesembrinus''). In ''Walking with Dinosaurs: A Natural History'', a companion book to the series, it was claimed that several large bone fragments from the Santana Group (known as Santana Formation in the book) of Brazil had indicated that ''O. mesembrinus'' may have had a wingspan reaching and a weight of , making it one of the largest known pterosaurs.Haines, T., 1999, ''"Walking with Dinosaurs": A Natural History'', BBC Books, p. 158 However, the largest definite ''Ornithocheirus mesembrinus'' specimens described at the time measured , in terms of wingspan. The specimens which the producers of the program used to justify such a large size estimate were described in 2012, and were under study by Dave Martill and David Unwin at the time of ''Walking With Dinosaurs production. The final description of the remains found a maximum estimated wingspan of for this large specimen. Unwin stated that he did not believe the higher estimate used by the BBC was likely, and that the producers likely chose the highest possible estimate because it was more "spectacular." Nevertheless, specimen MN 6594-V in 2013 was, at its degree of completeness, the largest known pterosaur individual.


See also

*
List of pterosaur genera This list of pterosaurs is a comprehensive listing of all Genus, genera that have ever been included in the order Pterosauria, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considere ...
*
Timeline of pterosaur research This timeline of pterosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and Biological taxonomy, taxonomic revisions of pterosaurs, the famed flying reptiles of the Mesozoic Era (ge ...


References

{{Portal bar, Paleontology, Brazil Pteranodontoidea Early Cretaceous pterosaurs of South America Aptian life Cretaceous Brazil Fossils of Brazil Romualdo Formation Fossil taxa described in 1987 Taxa named by Peter Wellnhofer