Baryonychines Temporal range: Early Cretaceous, Possible Santonian record | |
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Skeletal diagram of genera Suchomimus and Baryonyx | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Family: | † Spinosauridae |
Subfamily: | † Baryonychinae Charig & Milner, 1986 |
Type species | |
† Baryonyx walkeri Charig & Milner, 1986 | |
Subgroups | |
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Baryonychinae is an extinct clade or subfamily of spinosaurids from the Early Cretaceous (Valanginian-Albian) of Britain, Portugal, and Niger. The clade was named by Charig & Milner in 1986 and defined by Sereno et al. in 1998 and Holtz et al. in 2004 as all taxa more closely related to Baryonyx walkeri than to Spinosaurus aegyptiacus . [1]
Baryonychines were large, bipedal predators with elongated, crocodile-like skulls and lower jaw tips fanning out into rosettes bearing conical, often unserrated, teeth, and a distinct premaxillary notch. They possessed robust forelimbs supporting three-fingered hands with an enlarged first digit claw, to which the subfamily name indirectly refers. Members of this group, unlike the more derived Spinosaurinae, sported only low sails or none at all.
In 1820, paleontologist Gideon Mantell discovered numerous fossil teeth from the Wadhurst Clay Formation of Britain. [2] These were in 1841 named Suchosaurus cultridens by paleontologist Richard Owen, and were identified as a crocodilian. [3] A second species, Suchosaurus girardi , was named in 1897 by Henri-Émile Sauvage from the Papo Seco Formation of Portugal. [4] It was not until the description of Baryonyx in 1986 that these remains were identified as spinosaurid teeth and Suchosaurus was placed in the Spinosauridae.
The second described representative of the subfamily was unearthed in 1983 by fossil collector William John Walker, within the Smokejacks Pit, Weald Clay Formation, Surrey, England. This initiated the involvement of the Natural History Museum of London, discovering a 65% complete skeleton: NHMUK VP R9951. In 1986, the specimen was published and described by Alan J. Charig and Angela C. Milner as Baryonyx walkeri , [5] with a more detailed monograph published in 1997. [6] [7] Teeth, hand bones, and vertebrae attributed to the genus were later discovered in 1998 and 2004. [8] The same year, Spinosaurinae and Baryonychinae were cladistically defined by Holtz and colleagues. [1]
In 1973, paleontologist Philippe Taquet discovered specimen MNHN GDF 266 consisting of two premaxillae, a partial maxilla, and a dentary, along with several similar remains from Gadoufaoua, Elrhaz Formation, Niger. They were in 1998 described as the holotype and paratypes of Cristatusaurus lapparenti , [9] although after several inconclusive debates on whether or not the specimen represents the then newly described Baryonyx . [5] [6]
In 1997, Paul Sereno and colleagues discovered a ~67% complete skeleton, MNN GDF500, in Gadoufaoua. The next year, Sereno et al. described the specimen as the new baryonychine Suchomimus tenerensis . [10] The species was also the subject of synonymy disputes over Cristatusaurus and Baryonyx throughout the 1990s and 2000s. [11] [12]
From 2013 to 2020, several spinosaurid fragments were discovered from the Wessex Formation in Britain. In 2021, Barker et al. described these specimens, IWCMS 2014.95.5, IWCMS 2021.30, IWCMS 2014.95.1-3, IWCMS 2014.95.4, IWCMS 2014.95.6, IWCMS 2014.96.1, 2; 2020.448.1, 2, and IWCMS 2014.96.3, as the two new genera Ceratosuchops inferodios and Riparovenator milnerae . The study defined a new subclade within Baryonychinae: Ceratosuchopsini, defined as all taxa more closely related to Ceratosuchops inferodios than to Baryonyx walkeri. According to the performed analysis and clade definition, the group contains Ceratosuchops, Riparovenator, and Suchomimus. [13] [14]
In 2023, Santos-Cubedo et al. described a new genus and species of baryonychine, Protathlitis cinctorrensis , based on a partial skeleton, recovered from the Arcillas de Morella Formation of Castellón, Spain. [15]
Numerous undescribed specimens have been found as well, such as XMDFEC V0010, described in 2010 by Hone, Xu and Wang; a theropod tooth from the Majiacun Formation of China dated to ~86-85 million years ago. They interpreted the tooth as belonging to a probable baryonychine, which would expand the temporal range of Baryonychinae, and Megalosauroidea as a whole, well into the Late Cretaceous. [16] [17] However, this tooth lacks spinosaurid synapomorphies. [18] Other undescribed specimens include UT-JAW2 from Libya [19] and various remains from Spain, such as Baryonychinae indet. [20] from Vallipón, Castellote, Spain, LAD0-2 from Spain [21] CMP-2 from Cantera del Mas de la Parreta 1, [22] from Castilla y Leon, [23] from the El Castellar Formation, [24] Tenadas del Jabali, [25] and from Mas de Curolles. [26]
Even though baryonychines were on average smaller than the more advanced spinosaurines, they were still decently large compared to theropods in general. The smallest members, Ceratosuchops and Riparovenator , are estimated at 8–9 m (26–29 ft) and ~1.4-2 tons, while the largest member, Suchomimus , is estimated to measure 9.5–11 m (31 –36 ft) in length and 3–4.7 tons in weight. [27] [7] [28] Members of this family, like other spinosaurids, sported robust forelimbs with large, three-clawed hands. [29] [30] However, unlike the more derived spinosaurines, these animals possessed small sails, as in Suchomimus, Riparovenator, and Ceratosuchops (for the latter two, sails were assumed judging by their phylogenetic position); [10] [13] some with only the vertebrae of the sacral region being elongated, or none at all, as in Baryonyx. [6]
Like most other spinosaurids, baryonychines had a very elongated skull compared to other theropods. [29] Furthermore, even in comparison to the spinosaurines their skulls were long. Perhaps the most proportionally-lengthened skull belongs to Suchomimus . In its very crocodilian skull, there is little to no concavity or convexity from the front (premaxillae) to the back (parietals) of the skull, unlike in spinosaurines and most other theropods. [10] Baryonychines possess reduced antorbital fenestrae in comparison to other theropods, [31] with most of the front snout being solid bone formed by the premaxillae and maxillae. The tips of the premaxillae were expanded into a "terminal rosette" holding enlarged, recurved teeth. [32] Behind these expansions, baryonychines featured a subnarial gap complex where dentary teeth fit into, and, further posterior, a dentary gap that the large anteriormost maxillary teeth indented. [29] These animals also bore reduced, narrow premaxillary crests. [33]
The subfamily Baryonychinae was first implicitly named in 1986 by Alan J. Charig and Angela Milner when they named the family "Baryonychidae" to include Baryonyx . Those who name families are considered the nominal authors of the subfamilies also. The family Baryonychidae was invalidated when Baryonyx was found to be a spinosaurid. [34] Milner stated that it was likely that Suchosaurus belonged to this subfamily as well.
In 1998, the newly described Cristatusaurus was agreed to be very closely related to, if not identical to, Baryonyx by Charig & Milner, 1986 & 1997, [5] [6] Sereno, 1998, [10] and Rauhut, 2003. [12] Later in 1998, Sereno et al. described the genus Suchomimus , and placed it in Baryonychinae along with Baryonyx. They defined the clade's distinguishing characteristics as "numerous small-sized, serrated teeth in the dentary behind the terminal rosette and deeply-keeled anterior dorsal vertebrae." [10] By 2002, the conclusion was that the subfamily contained the genera Baryonyx, Cristatusaurus, Suchomimus, and Suchosaurus. [35] The clade was phylogenetically defined by Holtz et al. as all taxa more closely related to Baryonyx walkeri than to Spinosaurus aegyptiacus . [1]
In the 2012 description of Ichthyovenator , Allain et al. found it to belong to this subfamily, [36] although almost all subsequent studies have found otherwise, placing it in Spinosaurinae. [13] [37] [38]
Up until 2021, with Cristatusaurus and Suchosaurus being considered too incomplete and dubious, only the baryonychines Suchomimus and Baryonyx have been included in phylogenetic analyses, nearly always finding them to be sister genera in Baryonychinae, such as in the analysis performed by Arden et al. in 2018, shown below. [37]
Spinosauridae |
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In 2021, Chris Barker, Hone, Darren Naish, Andrea Cau, Lockwood, Foster, Clarkin, Schneider, and Gostling described two new spinosaurid species, Ceratosuchops inferodios and Riparovenator milnerae, and placed them well-supportedly in Baryonychinae. They placed them within the newly created tribe Ceratosuchopsini alongside Suchomimus. Barker et al. diagnosed three autapomorphies to distinguish the clade: "1. postorbital facet of frontal dorsoventrally thick (height more than 40% of length) and excavated by a deep, longitudinal slot; 2. well-defined and strongly curved anterior margins of supratemporal fossa; 3. occipital surface of the basisphenoid collateral oval scars excavated." Members of this clade range in length from 7.7 to 9.5 m (25.3 to 31 ft). [39] The results of their Bayesian analysis appear below: [13]
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Baryonychine teeth are small and recurved with little to no serrations, resembling those of crocodiles. These are considered adaptations for piscivory, as numerous recurved teeth aid in holding a struggling slippery animal within the jaws and down the throat; rather than the serrated teeth in most other theropods which are generalized for cutting and ripping flesh. [40] Vullo et al, 2016 likened the cranial evolution and adaptations to piscivory in spinosaurids to those of the Muraenesocidae, a modern family of predatory eels with a similarly evolved skull.[ citation needed ]
Baryonyx as one of the most complete representatives of the group shows evidence of a generalist behavior. One recorded instance is the holotype of Baryonyx found with both fish as well as a juvenile iguanodontid contents within the stomach region. [41] Another instance is pointed out by a 2016 study by the Belgian palaeontologist Christophe Hendrickx and colleagues. They found that adult spinosaurs could displace their mandibular rami (halves of the lower jaw) sideways when the jaw was depressed, which allowed the pharynx (opening that connects the mouth to the oesophagus) to be widened. This jaw-articulation is similar to that seen in pterosaurs and living pelicans, and would likewise have allowed spinosaurids to swallow large prey such as fish and other animals.[ citation needed ]
They also reported that the possible Portuguese Iberospinus [42] (formerly seen as Baryonyx) fossils were found associated with isolated Iguanodon teeth, and listed it along with other such associations as support for opportunistic feeding behaviour in spinosaurs. [33]
Spinosaurus is a genus of spinosaurid dinosaur that lived in what now is North Africa during the Cenomanian stage of the Late Cretaceous period, about 100 to 94 million years ago. The genus was known first from Egyptian remains discovered in 1912 and described by German palaeontologist Ernst Stromer in 1915. The original remains were destroyed in World War II, but additional material came to light in the early 21st century. It is unclear whether one or two species are represented in the fossils reported in the scientific literature. The best known species is S. aegyptiacus from Egypt, although a potential second species, S. maroccanus, has been recovered from Morocco. The contemporary spinosaurid genus Sigilmassasaurus has also been synonymized by some authors with S. aegyptiacus, though other researchers propose it to be a distinct taxon. Another possible junior synonym is Oxalaia from the Alcântara Formation in Brazil.
Irritator is a genus of spinosaurid dinosaur that lived in what is now Brazil during the Albian stage of the Early Cretaceous Period, about 113 to 110 million years ago. It is known from a nearly complete skull found in the Romualdo Formation of the Araripe Basin. Fossil dealers had acquired this skull and sold it to the State Museum of Natural History Stuttgart. In 1996, the specimen became the holotype of the type species Irritator challengeri. The genus name comes from the word "irritation", reflecting the feelings of paleontologists who found the skull had been heavily damaged and altered by the collectors. The species name is a homage to the fictional character Professor Challenger from Arthur Conan Doyle's novels.
Baryonyx is a genus of theropod dinosaur which lived in the Barremian stage of the Early Cretaceous period, about 130–125 million years ago. The first skeleton was discovered in 1983 in the Smokejack Clay Pit, of Surrey, England, in sediments of the Weald Clay Formation, and became the holotype specimen of Baryonyx walkeri, named by palaeontologists Alan J. Charig and Angela C. Milner in 1986. The generic name, Baryonyx, means "heavy claw" and alludes to the animal's very large claw on the first finger; the specific name, walkeri, refers to its discoverer, amateur fossil collector William J. Walker. The holotype specimen is one of the most complete theropod skeletons from the UK, and its discovery attracted media attention. Specimens later discovered in other parts of the United Kingdom and Iberia have also been assigned to the genus, though many have since been moved to new genera.
Carcharodontosaurus is a genus of carnivorous theropod dinosaur that lived in North Africa from about 100 to 94 million years ago during the Cenomanian age of the Late Cretaceous. Two teeth of the genus, now lost, were first described from Algeria by French paleontologists Charles Depéret and Justin Savornin as Megalosaurus saharicus. A partial skeleton was collected by crews of German paleontologist Ernst Stromer during a 1914 expedition to Egypt. Stromer did not report the Egyptian find until 1931, in which he dubbed the novel genus Carcharodontosaurus, making the type species C. saharicus. Unfortunately, this skeleton was destroyed during the Second World War. In 1995 a nearly complete skull of C. saharicus, the first well-preserved specimen to be found in almost a century, was discovered in the Kem Kem Beds of Morocco; it was designated the neotype in 1996. Fossils unearthed from the Echkar Formation of northern Niger were described and named as another species, C. iguidensis, in 2007.
Suchomimus is a genus of spinosaur dinosaur that lived between 125 and 112 million years ago in what is now Niger, north Africa, during the Aptian to early Albian stages of the Early Cretaceous period. It was named and described by paleontologist Paul Sereno and colleagues in 1998, based on a partial skeleton from the Elrhaz Formation. Suchomimus's long and shallow skull, similar to that of a crocodile, earns it its generic name, while the specific name Suchomimus tenerensis alludes to the locality of its first remains, the Ténéré Dese.
Spinosauridae is a clade or family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. Spinosaurid fossils have been recovered worldwide, including Africa, Europe, South America and Asia. Their remains have generally been attributed to the Early to Mid Cretaceous.
Afrovenator is a genus of megalosaurid theropod dinosaur from the Middle or Late Jurassic Period on the Tiourarén Formation and maybe the Irhazer II Formation of the Niger Sahara region in northern Africa. Afrovenator represents the only properly identified Gondwanan megalosaur, with proposed material of the group present in the Late Jurassic on Tacuarembó Formation of Uruguay and the Tendaguru Formation of Tanzania.
Siamosaurus is a genus of spinosaurid dinosaur that lived in what is now known as China and Thailand during the Early Cretaceous period and is the first reported spinosaurid from Asia. It is confidently known only from tooth fossils; the first were found in the Sao Khua Formation, with more teeth later recovered from the younger Khok Kruat Formation. The only species Siamosaurus suteethorni, whose name honours Thai palaeontologist Varavudh Suteethorn, was formally described in 1986. In 2009, four teeth from China previously attributed to a pliosaur—under the species "Sinopliosaurus" fusuiensis—were identified as those of a spinosaurid, possibly Siamosaurus. It is yet to be determined if two partial spinosaurid skeletons from Thailand and an isolated tooth from Japan also belong to Siamosaurus.
Cristatusaurus is a genus of theropod dinosaur that lived during the Early Cretaceous Period of what is now Niger, 112 million years ago. It was a baryonychine member of the Spinosauridae, a group of large bipedal carnivores with well-built forelimbs and elongated, crocodile-like skulls. The type species Cristatusaurus lapparenti was named in 1998 by scientists Philippe Taquet and Dale Russell, on the basis of jaw bones and some vertebrae. Two claw fossils were also later assigned to Cristatusaurus. The animal's generic name, which means "crested reptile", alludes to a sagittal crest on top of its snout; while the specific name is in honor of the French paleontologist Albert-Félix de Lapparent. Cristatusaurus is known from the Albian to Aptian Elrhaz Formation, where it would have coexisted with sauropod and iguanodontian dinosaurs, other theropods, and various crocodylomorphs.
Sigilmassasaurus is a controversial genus of spinosaurid dinosaur that lived approximately 100 to 94 million years ago during the Late Cretaceous Period in what is now northern Africa. Named in 1996 by Canadian paleontologist Dale Russell, it contains a single species, Sigilmassasaurus brevicollis. The identity of the genus has been debated by scientists, with some considering its fossils to represent material from the closely related species Spinosaurus aegyptiacus, while others have classified it as a separate taxon, forming the clade Spinosaurini with Spinosaurus as its sister taxon.
Suchosaurus is a spinosaurid dinosaur from Cretaceous England and Portugal, originally believed to be a genus of crocodile. The type material, consisting of teeth, was used by British palaeontologist Richard Owen to name the species S. cultridens in 1841. Later in 1897, French palaeontologist Henri-Émile Sauvage named a second species, S. girardi, based on two fragments from the mandible and one tooth discovered in Portugal. Suchosaurus is possibly a senior synonym of the contemporary spinosaurid Baryonyx, but is usually considered a dubious name due to the paucity of its remains, and is considered an indeterminate baryonychine. In the Wadhurst Clay Formation of what is now southern England, Suchosaurus lived alongside other dinosaurs, as well as plesiosaurs, mammals, and crocodyliforms.
Oxalaia is a genus of spinosaurid dinosaur that lived in what is now the Northeast Region of Brazil during the Cenomanian stage of the Late Cretaceous period, sometime between 100.5 and 93.9 million years ago. Its only known fossils were found in 1999 on Cajual Island in the rocks of the Alcântara Formation, which is known for its abundance of fragmentary, isolated fossil specimens. The remains of Oxalaia were described in 2011 by Brazilian palaeontologist Alexander Kellner and colleagues, who assigned the specimens to a new genus containing one species, Oxalaia quilombensis. The species name refers to the Brazilian quilombo settlements. Oxalaia quilombensis is the eighth officially named theropod species from Brazil and the largest carnivorous dinosaur discovered there. It is closely related to the African genus Spinosaurus, and/or may be a junior synonym of this taxon.
Ichthyovenator is a genus of spinosaurid dinosaur that lived in what is now Laos, sometime between 125 and 113 million years ago, during the Aptian stage of the Early Cretaceous period. It is known from fossils collected from the Grès supérieurs Formation of the Savannakhet Basin, the first of which were found in 2010, consisting of a partial skeleton without the skull or limbs. This specimen became the holotype of the new genus and species Ichthyovenator laosensis, and was described by palaeontologist Ronan Allain and colleagues in 2012. The generic name, meaning "fish hunter", refers to its assumed piscivorous lifestyle, while the specific name alludes to the country of Laos. In 2014, it was announced that more remains from the dig site had been recovered; these fossils included teeth, more vertebrae (backbones) and a pubic bone from the same individual.
Ostafrikasaurus is a genus of theropod dinosaur from the Late Jurassic period of what is now Lindi Region, Tanzania. It is known only from fossil teeth discovered sometime between 1909 and 1912, during an expedition to the Tendaguru Formation by the Natural History Museum of Berlin. Eight teeth were originally attributed to the dubious dinosaur genus Labrosaurus, and later to Ceratosaurus, both known from the North American Morrison Formation. Subsequent studies attributed two of these teeth to a spinosaurid dinosaur, and in 2012, Ostafrikasaurus crassiserratus was named by French palaeontologist Eric Buffetaut, with one tooth as the holotype, and the other referred to the same species. The generic name comes from the German word for German East Africa, the former name of the colony in which the fossils were found, while the specific name comes from the Latin words for "thick" and "serrated", in reference to the form of the animal's teeth.
Camarillasaurus is a genus of theropod dinosaur from the Early Cretaceous period (Barremian) of Camarillas, Teruel Province, in what is now northeastern Spain. Described in 2014, it was originally identified as a ceratosaurian theropod, but later studies suggested affinities to the Spinosauridae. If it does represent a spinosaur, Camarillasaurus would be one of several spinosaurid taxa known from the Iberian peninsula, the others being Iberospinus, Protathlitis, ‘’Baryonyx’’, Riojavenatrix, and Vallibonavenatrix.
Vallibonavenatrix is a genus of spinosaurid dinosaur from the Early Cretaceous (Barremian) Arcillas de Morella Formation of Castellón, Spain. The type and only species is Vallibonavenatrix cani, known from a partial skeleton.
Ceratosuchops is a genus of spinosaurid from the Early Cretaceous (Barremian) of Britain.
Riparovenator is a genus of baryonychine spinosaurid dinosaur from the Early Cretaceous (Barremian) period of Britain. The genus contains a single species, Riparovenator milnerae.
IberospinusIPA:[aɪbiːʌroʊs̠piːnʊs̠] or IPA:[aɪbiːʌroʊs̠paɪnʌs̠] is an extinct genus of spinosaurid dinosaur from the Early Cretaceous (Barremian) Papo Seco Formation of Portugal. The genus contains a single species, I. natarioi, known from several assorted bones belonging to one individual. Iberospinus represents one of five known spinosaurid taxa from the Iberian Peninsula, the others being Camarillasaurus, Protathlitis, Riojavenatrix, and Vallibonavenatrix. It is important for its implications of the geographical origin of Spinosauridae and the suggested presence of an at least semi-aquatic lifestyle early in the evolution of this clade.
Riojavenatrix is a genus of spinosaurid theropod from the Early Cretaceous Enciso Group of La Rioja, Spain. The type species is Riojavenatrix lacustris. Riojavenatrix represents one of five known spinosaurid taxa from the Iberian Peninsula, the others being Camarillasaurus, Iberospinus, Protathlitis, and Vallibonavenatrix.