Baryonychinae is an extinct clade or subfamily of spinosaurids from the Early Cretaceous (Valanginian-Albian) of Britain, Portugal, and Niger. In 2021, it consisted of six genera: Ceratosuchops, Cristatusaurus, Riparovenator, Suchomimus, Suchosaurus, and Baryonyx, the nominal genus. 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 Henry-Emile 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]