Titanochampsa Temporal range: Late Cretaceous, | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Archosauria |
Clade: | Pseudosuchia |
Clade: | Crocodylomorpha |
Clade: | Crocodyliformes |
Clade: | Mesoeucrocodylia |
Genus: | † Titanochampsa Fachini et al., 2022 |
Species: | †T. iorii |
Binomial name | |
†Titanochampsa iorii Fachini et al., 2022 | |
Titanochampsa type locality in São Paulo State, Brazil |
Titanochampsa is a genus of large mesoeucrocodylian from the Maastrichtian Marilia Formation of Brazil. Although only known from a single skull roof, the material shows that Titanochampsa was not a member of Notosuchia, which were previously believed to have been the only crocodyliforms present in the strata of the Bauru Group. Body size estimates vary greatly and range between 2.98–5.88 m (9 ft 9 in – 19 ft 3 in) due to the incomplete nature of the holotype fossil. The overall anatomy of the skull roof, alongside its size and possible affinities with Neosuchians, may suggest that it was a semi-aquatic ambush hunter similar to modern crocodilians. [1]
Titanochampsa is only known from a single fossil, holotype specimen MPMA 02–0005/87, a partial skull roof of great size. This fossil was discovered in layers of the Marilia Formation in the Monte Alto municipality of southeast Brazil, a region which is otherwise dominated by the older Adamantina Formation. The strata of the Marilia Formation correspond with the Maastrichtian age. The initial discovery of the fossil was made in 1987 and the remains were subsequently thought to have belonged to a titanosaur sauropod, partly due to its great size. Later research conducted on the specimen however revealed it to have belonged to some kind of crocodyliform and a brief description was published by Iori and Arruda-Campos in 2016. [2] In this paper the material was primarily compared to other Notosuchians, but no precise assignment was made. A more detailed description was eventually published by Fachini and colleagues six years later, conducting a thorough phylogenetic analysis and establishing a distinct genus for the material. [1]
The name Titanochampsa derives from the Greek "titan", in allusion to the fossil's size and prior titanosaur assignment, and "champsus" meaning crocodile. The species name was chosen to honor Fabiano V. Ior, a Brazilian paleontologist who had previously worked on the remains and recognized them to have belonged to a crocodyliform. [1]
The type specimen of Titanochampsa represents a single incomplete skull roof preserving most of the right side including the parietal bone, frontal bone, squamosal and postorbital. The quadratojugal and supraoccipital are less well preserved. The ornamentation is still visible on parts of the skull despite the abbrasion of the external surface and consists of faint groves and pits spaced at regular intervals. This sets them apart from baurusuchids, which possess different ornamentation across different parts of the skull, as well as peirosaurids and modern crocodilians, in which the pits and groves are more pronounced. The supratemporal fenestrae are approximately triangular and both externally as well as internally large, making up 50% of the skull roof and suggesting the presence of powerful adductor muscles on the lower jaw. The animal's autapomorphies include the anteroposterior projections of the squamosal and parietal, which are about as long as the supratemporal fenestrae, a postorbital-supratemporal bar thicker than the corresponding element of the squamosal and a grove exclusively located on the squamosal that would hold the upper earlid. [1]
In an attempt to estimate the skull length of Titanochampsa the width of the skull table was measured and compared to various crocodyliforms that fall into the same general size range. Due to the uncertain placement of the animal a variety of other taxa were used including both extant species like the American alligator and American crocodile as well as extinct genera like Stratiotosuchus , Uberabasuchus and Eosuchus . The vastly different morphology and ecology of these taxa resulted in very different lower and upper skull length estimates, ranging from 37.01–74.43 cm (14.57–29.30 in). Due to this large difference, body length was estimated for both values rather than using a mean, giving a potential total length of 2.98–5.88 m (9 ft 9 in – 19 ft 3 in). [1]
Two phylogenetic analysis, one based on Martínez et al. 2018 and another based on Ruiz et al. 2021, were conducted, both of which recovering Titanochampsa nested deep within Neosuchia, more specifically within Eusuchia. The Martínez dataset recovers Titanochampsa in a large polytomy at the base of Longirostres alongside Argochampsa , Asiatosuchus germanicus and the extant Crocodylus genus. However, there is little support for this arrangement and the only supporting synapomorphy can not be determined in Titanochampsa. In general this analysis provides little evidence for the taxon's placement within Neosuchia. Following the matrix of Ruiz, another polytomy was recovered, however in this instance the polytomy includes several more basal Eusuchian taxa such as Allodaposuchus , Hylaeochampsa , Iharkutosuchus and the Susisuchidae. However much like in the other analysis, of the few characters supporting this grouping none can be found in Titanochampsa and only few directly support its placement as a Neosuchian. Subsequently, Fachini and colleagues hesitate to assign Titanochampsa even to Neosuchia, instead only specifying its classification as a mesoeucrocodylian. There are however several non-synapomorphic traits linking the taxon to Neosuchians, such as the rectangular skull table and flat supratemporal rim. [1]
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However, while the authors were unable to fully support Neosuchian affinities, they were capable of clearly distinguishing the genus from Notosuchians. Titanochampsa differs from baurusuchids through twelve anatomical characters, two of which are synapomorphies of the family. The skull table in general differs widely from any known baurusuchid. Likewise, the authors also point towards several key differences between Titanochampsa and peirosaurids, another clade of crocodylomorphs prominently present in the Bauru group. [1]
Research conducted on the Marilia Formation suggests that it was formed by fluvial deposits under arid to semiarid conditions. Specifically, it is hypothesized that the Marilia sediments represent the distal end of such a system, closer to the origin of the individual rivers. This would explain the relative abundance of fossils discovered in the Serra da Galga Formation (formerly considered to be a part of the same formation) compared to the Marilia Formation where Titanochampsa had been found. Overall these conditions suggest that Titanochampsa was native to ephemeral bodies of water in the distal ends of a fluvial system. [1]
The notosuchians which are commonly found in other stratigraphic units of the Bauru group are thought to have had relatively weak bite forces and the largest known predatory species appear to have reached a maximum length of approximately 4 m (13 ft). Compared to that, Titanochampsa possesses large internal supratemporal fenestra allowing for a much stronger bite and following the body size estimates it would likely be comparable to the larger notosuchian taxa of the older Adamantina Formation. The strong bite and great size, coupled with the possible affinities with eusuchians and environmental conditions, might suggest that Titanochampsa was a semi-aquatic ambush hunter similar to modern crocodilians. This would strongly set it apart from the other, primarily terrestrial, crocodyliforms of the Bauru Group. Fachini and colleagues speculate that the appearance of a crocodyliform with this lifestyle might tie into the climatic changes the area underwent during the later phases of this time period, however they note that more material would be required to be certain. [1]
Mahajangasuchus is an extinct genus of crocodyliform which had blunt, conical teeth. The type species, M. insignis, lived during the Late Cretaceous; its fossils have been found in the Maevarano Formation in northern Madagascar. It was a fairly large predator, measuring up to 4 metres (13 ft) long.
Mariliasuchus is an extinct genus of Late Cretaceous notosuchian mesoeucrocodylian found near Marilia, Brazil. The first bone remains were found and collected in 1995 by Brazilian paleontologist William Nava, in red rocks from the fossiliferous Adamantina Formation. Four years later, it was described as Mariliasuchus amarali, by Brazilian paleontologists Ismar de Souza Carvalho and Reinaldo J. Bertini.
Razanandrongobe is a genus of carnivorous ziphosuchian crocodyliform from the Middle Jurassic of Madagascar. It contains the type and only species Razanandrongobe sakalavae, named in 2004 by Simone Maganuco and colleagues based on isolated bones found in 2003. The remains, which included a fragment of maxilla and teeth, originated from the Bathonian-aged Sakaraha Formation of Mahajanga, Madagascar. While they clearly belonged to a member of the Archosauria, Maganuco and colleagues refrained from assigning the genus to a specific group because the fragmentary remains resembled lineages among both the theropod dinosaurs and crocodylomorphs.
Notosuchia is a suborder of primarily Gondwanan mesoeucrocodylian crocodylomorphs that lived during the Jurassic and Cretaceous. Some phylogenies recover Sebecosuchia as a clade within Notosuchia, others as a sister group ; if Sebecosuchia is included within Notosuchia its existence is pushed into the Middle Miocene, about 11 million years ago. Fossils have been found from South America, Africa, Asia, and Europe. Notosuchia was a clade of terrestrial crocodilians that evolved a range of feeding behaviours, including herbivory (Chimaerasuchus), omnivory (Simosuchus), and terrestrial hypercarnivory (Baurusuchus). It included many members with highly derived traits unusual for crocodylomorphs, including mammal-like teeth, flexible bands of shield-like body armor similar to those of armadillos (Armadillosuchus), and possibly fleshy cheeks and pig-like snouts (Notosuchus). The suborder was first named in 1971 by Zulma Gasparini and has since undergone many phylogenetic revisions.
Peirosauridae is a Gondwanan family of mesoeucrocodylians that lived during the Cretaceous period. It was a clade of terrestrial crocodyliforms that evolved a rather dog-like skull, and were terrestrial carnivores. It was phylogenetically defined in 2004 as the most recent common ancestor of Peirosaurus and Lomasuchinae and all of its descendants. Lomasuchinae is a subfamily of peirosaurids that includes the genus Lomasuchus.
Baurusuchidae is a Gondwanan family of mesoeucrocodylians that lived during the Late Cretaceous. It is a group of terrestrial hypercarnivorous crocodilians from South America and possibly Pakistan. Baurusuchidae has been, in accordance with the PhyloCode, officially defined as the least inclusive clade containing Cynodontosuchus rothi, Pissarrachampsa sera, and Baurusuchus pachecoi. Baurusuchids have been placed in the suborder Baurusuchia, and two subfamilies have been proposed: Baurusuchinae and Pissarrachampsinae.
The Marília Formation is a geological formation in Minas Gerais state of southeastern Brazil. Its strata date back to the Maastrichtian, and are part of the Bauru Group.
Trematochampsidae is an extinct family of mesoeucrocodylian crocodylomorphs. Fossils are present from Madagascar, Morocco, Niger, Argentina, and Brazil. Possible trematochampsids have been found from Spain and France, but classification past the family level is indeterminant. The trematochampsids first appeared during the Barremian stage of the Early Cretaceous and became extinct during the late Maastrichtian stage of the Late Cretaceous.
Armadillosuchus is an extinct genus of sphagesaurid crocodylomorph. It was described in February 2009 from the late Campanian to early Maastrichtian Adamantina Formation of the Bauru Basin in Brazil, dating to approximately 70 Ma. Armadillosuchus was among the larger and more robust sphagesaurids, with a total length of approximately 2 metres (6.6 ft).
Kaprosuchus is an extinct genus of mahajangasuchid crocodyliform. It is known from a single nearly complete skull collected from the Upper Cretaceous Echkar Formation of Niger. The name means "boar crocodile" from the Greek κάπρος, kapros ("boar") and σοῦχος, soukhos ("crocodile") in reference to its unusually large caniniform teeth which resemble those of a boar. It has been nicknamed "BoarCroc" by Paul Sereno and Hans Larsson, who first described the genus in a monograph published in ZooKeys in 2009 along with other Saharan crocodyliformes such as Anatosuchus and Laganosuchus. The type species is K. saharicus.
Sebecus is an extinct genus of sebecid crocodylomorph from Eocene of South America. Like other sebecosuchians, it was entirely terrestrial and carnivorous. The genus is currently represented by two species, the type S. icaeorhinus and S. ayrampu. Several other species have been referred to Sebecus, but were later reclassified as their own genera.
Sebecia is an extinct clade of mesoeucrocodylian crocodyliforms that includes peirosaurids and sebecids. It was first constructed in 2007 to include Hamadasuchus, Peirosauridae, and Sebecus. It was initially considered to be the sister taxon of the clade Neosuchia, which includes living crocodilians, although some later studies have placed it within Neosuchia as a basal clade. Sebecians were terrestrial crocodyliforms characterized by their deep snouts and ziphodont dentition. They first appeared in the Late Cretaceous, survived the Cretaceous–Paleogene extinction event, and became extinct in the Miocene epoch.
Sebecosuchia is an extinct group of mesoeucrocodylian crocodyliforms that includes the families Sebecidae and Baurusuchidae. The group was long thought to have first appeared in the Late Cretaceous with the baurusuchids and become extinct in the Miocene with the last sebecids, but Razanandrongobe pushes the origin of Sebecosuchia to the Middle Jurassic. Fossils have been found primarily from South America but have also been found in Europe, North Africa, Madagascar, and the Indian subcontinent.
Stratiotosuchus is an extinct genus of baurusuchid mesoeucrocodylian from the Adamantina Formation in Brazil. It lived during the Late Cretaceous. The first fossils were found in the 1980s, and the type species Stratiotosuchus maxhechti was named in 2001. A hyperpredator, it and other baurusuchids may have filled niches occupied elsewhere by theropod dinosaurs.
Susisuchus is an extinct genus of neosuchian mesoeucrocodylian crocodyliform from the Early Cretaceous of Brazil. Fossils have been found from the Nova Olinda Member of the Aptian-age Crato Formation in the Araripe and Lima Campos Basins of northeastern Brazil. Named in 2003, Susisuchus is the sole member of the family Susisuchidae, and is closely related to the clade Eusuchia, which includes living crocodilians. The type species is S. anatoceps, known from a single partial articulated skeleton that preserves some soft tissue. A second species, S. jaguaribensis, was named in 2009 from fragmentary remains.
Campinasuchus is an extinct genus of baurusuchid mesoeucrocodylian from Minas Gerais State of Brazil.
Pissarrachampsa is an extinct genus of baurusuchid mesoeucrocodylian from the Late Cretaceous of Brazil. It is based on a nearly complete skull and a referred partial skull and lower jaw from the ?Campanian - ?Maastrichtian-age Vale do Rio do Peixe Formation of the Bauru Group, found in the vicinity of Gurinhatã, Brazil.
Sahitisuchus is an extinct genus of sebecid mesoeucrocodylian known from Rio de Janeiro State of southeastern Brazil. It contains a single species, Sahitisuchus fluminensis. It is a terrestrial sebecid, however also adopted to a semi-aquatic lifestyle to some degree, most probably coexisting with the semi-aquatic alligatorid Eocaiman itaboraiensis.
Aplestosuchus is an extinct genus of baurusuchid mesoeucrocodylian known from the Late Cretaceous Adamantina Formation of São Paulo, southern Brazil. It contains a single species, Aplestosuchus sordidus. A. sordidus is represented by a single articulated and nearly complete skeleton, preserving the remains of an unidentified sphagesaurid crocodyliform in its abdominal cavity. The specimen represents direct evidence of predation between different taxa of crocodyliforms in the fossil record.
Coelognathosuchia is an extinct clade of neosuchian crocodyliforms that includes all taxa more closely related to the family Pholidosauridae than to Bernissartia fagesii or Eusuchia. Martin et al. (2014) named the clade after finding goniopholidids and pholidosaurids to group together in their phylogenetic analysis of crocodyliform evolutionary relationships. In their analysis, Pholidosauridae was monophyletic and Goniopholididae was paraphyletic, being an assemblage of successively more basal taxa within Coelognathosuchia. Coelognathosuchia itself was positioned near the base of the larger clade Neosuchia as the sister group to a clade containing the Early Cretaceous neosuchian Bernissartia and Eusuchia, the group that includes all modern crocodilians and their closest extinct relatives.