Concavenator corcovatus

Concavenator inhabited the subtropical paleoenvironment of the La Huérguina Formation in what is now Cuenca Province, Spain. The Las Hoyas site was a seasonal wetland with shallow lakes, swamps, and temporary rivers. The climate was warm and seasonal, with drought periods alternating with floods. The ecosystem included fish (Lepidotes), turtles, crocodilians (Goniopholis), lizards, amphibians, primitive birds (Iberomesornis, Eoalulavis), pterosaurs, and small theropods like Pelecanimimus. Concavenator was the apex terrestrial predator of this ecosystem.

As the apex terrestrial predator of Las Hoyas, Concavenator likely hunted a variety of prey available in the lacustrine ecosystem. Probable prey included the ornithomimosaurid Pelecanimimus and other medium-sized dinosaurs, as well as crocodilians, turtles, and possibly fish. Its teeth were serrated and recurved, typical of active carnivores. Ichnological evidence from Las Hoyas (large theropod trackways) suggests animals of Concavenator's size crossed shallow water areas, potentially pursuing aquatic prey or drinking water.

There is no direct evidence of Concavenator social behavior, given that only one specimen is known. The dorsal hump formed by vertebrae D11 and D12 may have served intraspecific display, species identification, thermoregulation, or fat storage functions. The trackway described by Herrera-Castillo et al. (2022) at Las Hoyas, attributable to a Concavenator-sized theropod with a pathological foot, suggests that injured or malformed animals remained active in the ecosystem. The possible quill knobs on the forearm are debated: they may indicate vestigial secondary feathers used in display or intraspecific recognition.

Analysis of Concavenator vertebrae reveals extensive pneumatization, consistent with an avian-style air sac respiratory system typical of derived theropods. This implies elevated metabolism consistent with endothermy. Bone growth of the holotype, based on available histology, suggests the found specimen was subadult or young adult. The possible presence of filamentous structures (quill knobs) indicates at least parts of the body may have had non-scaly covering. Scale impressions preserved on the feet show a pattern similar to modern birds (avian podotheca), reflecting the close evolutionary relationship between theropods and birds.

The founding paper describing Concavenator corcovatus from holotype MCCM-LH 6666, a nearly complete skeleton from Barremian-age Las Hoyas deposits. Ortega, Escaso, and Sanz identify two anatomical characters unprecedented in carcharodontosaurids: dorsal vertebrae D11 and D12 with extremely elongated neural spines forming a hump- or sail-like structure; and small bumps on the ulna morphologically comparable to avian quill knobs. Phylogenetic parsimony analysis recovers Concavenator as a basal member of Carcharodontosauridae, close to Neovenator. The paper was published in Nature to wide scientific and media attention, as possible feather evidence in a carcharodontosaurid challenges the hypothesis that secondary feathers evolved only in more derived theropods. The analysis inaugurated a series of dedicated anatomical studies on the specimen in the following decades.

Holotype MCCM-LH 6666 of Concavenator corcovatus at Las Hoyas — the most complete carcharodontosaurid specimen ever found, described by Ortega, Escaso, and Sanz in 2010 in Nature.

Scientific reconstruction of Concavenator corcovatus by Daniel Vidal (2012), prepared with supervision from the original paper's authors, highlighting the dorsal hump formed by the elongated vertebrae.

Cuesta et al. describe in detail the scale impressions preserved on the feet of the Concavenator holotype, the first confirmed podotheca (scaly foot covering) evidence in a non-avian dinosaur. Comparative analysis with modern birds and crocodilians reveals a pattern of rectangular scales on the underside of the tail, bird-like scutes on the feet, and plantar pads on the undersides of the toes. The work discusses phylogenetic implications: the integumentary pattern is closer to birds than to squamate reptiles, suggesting avian-style foot covering is a synapomorphy of a broader clade including Concavenator. The study reinforces Las Hoyas as one of the world's most exceptional soft-tissue preservation sites for dinosaurs.

Paleontologists Fernando Escaso, Francisco Ortega, and José Luis Sanz examine Concavenator fossils, including the foot scale impressions studied by Cuesta et al. (2015).

Restored skull diagram of Concavenator corcovatus based on a 3D model published in a 2019 study. The exceptional preservation of the holotype also enabled the skin impression study described in 2015.

Cuesta, Ortega, and Sanz present the most comprehensive revision of Concavenator cranial osteology ever published, based on additional preparation of the holotype and 3D modeling. The study systematically describes each bone of the skull, mandible, and temporal region, cataloging new diagnostic characters not recognized in the original 2010 description. The revised phylogenetic analysis with new cranial data confirms Concavenator as a basal member of Carcharodontosauridae, close to Neovenator and Lusovenator, but recovers a slightly different topology for internal family nodes. The paper documents for the first time the detailed cranial fenestration of the specimen, discussing functional implications of pneumatic air chambers in the skull for mass reduction and possible cranial thermoregulation.

Size comparison between Concavenator corcovatus and a human. The ~6-meter body size is well known from the nearly complete holotype, whose skull was described in detail by Cuesta, Ortega, and Sanz (2018).

Artistic reconstruction of Concavenator corcovatus (TheDubstepAddict, 2016). The cranial morphology described in detail by Cuesta, Ortega, and Sanz (2018) reveals the typical carcharodontosaurid skull architecture.

This study provides a detailed description of Concavenator's axial skeleton, focusing on dorsal vertebrae D11 and D12 whose neural spines are extremely elongated. Cuesta, Ortega, and Sanz measure and compare these spines with those of other theropods, sauropods, and ornithischians with similar structures (such as Spinosaurus and Ouranosaurus), ruling out a true sail and proposing the structure was a compact hump, possibly containing fat reserves or serving thermoregulation. Analysis of vertebral pneumatization reveals air sacs penetrated deeply into the vertebral column, evidencing a sophisticated avian-style respiratory system in a basal carcharodontosaurid. The paper includes description of cervical, dorsal, and gastralia ribs, and discusses biomechanical implications of the vertebral column for locomotion and posture.

Skeletal mount of Concavenator corcovatus on display in Japan (2017). The hump formed by vertebrae D11 and D12 is clearly visible above the hip region, as described by the 2018 axial osteology study.

Artistic reconstruction of Concavenator corcovatus by TotalDino (2023), showing the morphology of the dorsal hump and possible quill knobs on the forearm, central features of the axial and appendicular osteology.

The third paper in Cuesta, Ortega, and Sanz's monographic series on Concavenator, dedicated to appendicular osteology: pectoral and pelvic girdles, humerus, radius, ulna, hand, femur, tibia, fibula, and foot. The most discussed aspect is the re-analysis of the ulnar bumps described by Ortega et al. (2010) as possible quill knobs. Using additional preparation techniques and scanning electron microscopy, the authors describe the structures with greater precision and discuss whether they represent follicular ligament insertions (as in birds), muscle scars, or both. The paper also describes functional foot morphology, showing adaptations consistent with bipedal locomotion on semi-solid substrate, coherent with Las Hoyas' lacustrine environment. Femur and tibia morphology is compared with other carcharodontosaurids, providing new data for locomotor speed inferences.

Skeletal mount of Concavenator in lateral view in Japan (2017). The appendicular osteology described in detail by Cuesta et al. (2018) covers the entire limb and girdle structure visible in this mount.

Size comparison among Carcharodontosauridae members, including Concavenator (smallest figure). The appendicular osteology described in 2018 enables direct comparisons with larger species such as Giganotosaurus and Carcharodontosaurus.

Canale et al. describe Meraxes gigas, a new giant carcharodontosaurid from Argentina, and perform the most comprehensive phylogenetic analysis of the family through 2022. Concavenator is recovered as a basal member of Carcharodontosauridae, positioned close to Neovenator and Lusovenator in a clade of small-to-medium carcharodontosaurids. One of the study's most important findings is the demonstration that forelimb reduction in large theropods (T. rex, Giganotosaurus, Carnotaurus) occurred convergently and independently in multiple lineages, not through inheritance from a common ancestor. Concavenator, with relatively well-developed arms for its size, represents a plesiomorphic condition within the family. The paper provides the current reference phylogenetic framework for Carcharodontosauridae and is the most-cited analysis for Concavenator positioning.

Reconstruction of Concavenator corcovatus chasing a Mantellisaurus atherfieldensis (ABelov2014, 2022). Canale et al. (2022) placed Concavenator as a basal member of Carcharodontosauridae, separate from the South American giants.

Phylogenetic family tree of Carnosauria (Eddy & Clarke, 2011, PLoS ONE), showing relationships among large carnivorous theropods. Concavenator is placed in Carcharodontosauridae, as confirmed and refined by Canale et al. (2022).

Kellermann, Cuesta, and Rauhut re-evaluate a partial carcharodontosaurid specimen from Egypt destroyed in World War II, proposing the new genus Tameryraptor markgrafi for the Egyptian fauna and rejecting its synonymy with Carcharodontosaurus saharicus from Morocco. Phylogenetic analysis includes Concavenator and, in some scenarios, recovers it as a taxon of uncertain position outside Carcharodontosauridae sensu stricto, positioned as sister clade to Siamraptor within Carcharodontosauria. The paper is relevant to Concavenator because it is co-authored by Elena Cuesta, the researcher who produced the entire monographic series on the specimen, and because it directly questions the traditional monophyly of Carcharodontosauridae as conceived since Sereno et al. (1996). The publication represents the most current state of the phylogenetic debate on Concavenator's position.

Scientific reconstruction of Concavenator corcovatus (Mario Lanzas, 2021). The exact phylogenetic position of the animal within or outside Carcharodontosauridae remains debated, as demonstrated by the re-analysis of Kellermann et al. (2025).

Reconstruction of Concavenator corcovatus by Mario Lanzas (2019). The animal's general morphology is well understood thanks to the nearly complete holotype, but its exact phylogeny remains actively debated.

Barrios-de Pedro et al. describe over 2,000 fossil coprolites from the Las Hoyas site, the same Early Cretaceous ecosystem that produced Concavenator. Morphological analysis of 433 specimens reveals an assemblage dominated by cylindrical and lace-thin morphotypes, attributable to carnivores with fish-based diets. The paper provides direct evidence of trophic interactions in the ecosystem: the most likely producers of the largest coprolites are large theropods such as Concavenator. Exceptional coprolite preservation at Las Hoyas, related to microbial mat development on lake bottoms, is the same phenomenon that preserved Concavenator's articulated skeleton. The study integrates ichnological, sedimentological, and paleobiological data to reconstruct the Barremian Iberian food web, positioning Concavenator at the apex of the terrestrial trophic pyramid.

Geological map and location of the Las Hoyas site (La Huérguina Formation), where Concavenator was found and from which the coprolites analyzed by Barrios-de Pedro et al. (2018) were collected.

Las Hoyas excavation site before fossil extraction. The same layers that preserved Concavenator's skeleton contain the carnivore coprolites studied by Barrios-de Pedro et al. (2018).

Buscalioni and Fregenal-Martínez present the most complete paleoecological synthesis of the Las Hoyas Konservat-Lagerstätte, the site that produced Concavenator. The paper interprets the depositional environment as a subtropical seasonal wetland with strong, climatically driven cyclical water level oscillations at a regional scale. This scenario explains exceptional fossil preservation: during drought phases, microbial mats developed on the muddy bottoms of shallow lakes; when water levels rose again, dead organisms — including large vertebrates like Concavenator — were rapidly engulfed and sealed by the mats, inhibiting decay. The reconstructed ecosystem includes fish, turtles, crocodilians, lizards, primitive birds (Iberomesornis, Eoalulavis), pterosaurs, small theropods (Pelecanimimus), and Concavenator at the apex of the terrestrial food chain.

Artistic reconstruction of Concavenator corcovatus hunting a Pelecanimimus polyodon at the shores of a Barremian lake. Both animals inhabited the same Las Hoyas lacustrine ecosystem described by Buscalioni & Fregenal-Martínez (2010).

Concavenator pursuing a Pelecanimimus in Early Cretaceous Spain (Durbed, 2012). The lacustrine palaeoenvironment of Las Hoyas is central to understanding both the exceptional preservation of the fossil and the predator's ecology.

Herrera-Castillo et al. describe a trackway (LH-Mg-10-16) from Las Hoyas with unusual features: wide steps and a set of equally deformed left footprints with a dislocated digit. Using ichnological analysis, 3D scanning, thin sections, and geometric morphometrics compared with 75 bipedal dinosaur trackways, the authors conclude the prints were made by a single large theropod with a pathological foot, estimating hip height at approximately 2 meters. This size is compatible with Concavenator, the only large theropod known from Las Hoyas. The paper provides ichnological evidence of behavior and pathology in a theropod that may be Concavenator, complementing anatomical data from the skeletal holotype. The trackway suggests the animal crossed a shallow water area walking slowly toward the main water source.

Reconstruction of Concavenator in an aquatic environment (AntoninJury, 2015). The Las Hoyas ichnological trackway studied by Herrera-Castillo et al. (2022) indicates a Concavenator-sized theropod crossed a shallow water area with a pathological foot.

Reconstruction of Concavenator corcovatus by Jesus Gamarra Gonzalez (2017), showing the hind limbs and foot morphology. The trackway described by Herrera-Castillo et al. (2022) provides behavioral and pathological evidence on a large Las Hoyas theropod.

Hendrickx et al. produce the most comprehensive review ever published on integumentary structures in non-avian theropods, cataloging and analyzing scale impressions, dermal ossifications, quill knobs, and other structures in dozens of taxa. Concavenator occupies a central position in the analysis: it is cited as the most basal non-avian theropod with possible quill knobs (ulnar bumps) and as the only carcharodontosaurid with preserved scale impressions. The paper discusses the phylogenetic distribution of integumentary structures, concluding that reptilian scales and feathers coexisted in many Mesozoic theropods and that Concavenator's evidence is consistent with a mixed covering of scales and filamentous structures on parts of the body. The authors critically evaluate the interpretation of the ulnar bumps as true quill knobs versus muscle scars, leaving the question open.

Reconstruction of Concavenator corcovatus using its hump for thermoregulation (Emily Willoughby, 2011). Hendrickx et al. (2022) discuss integumentary structures and thermoregulation in non-avian theropods with unique dorsal features.

Scale comparison of Concavenator (Slate Weasel, public domain). Its relatively small size compared to other carcharodontosaurids is relevant to Hendrickx et al. (2022) discussion of integumentary structure distribution across the body.

Novas et al. synthesize the evolution of carnivorous dinosaurs in Cretaceous Patagonia, discussing the origin and dispersal of large carcharodontosaurids between supercontinents. Concavenator is discussed in biogeographic context: its discovery in Spain suggests medium-sized carcharodontosaurids inhabited Europe in the Barremian before the South American giants (Giganotosaurus, Mapusaurus, Tyrannotitan) diversified in the Albian-Cenomanian. The paper proposes that the lineage leading to Concavenator and Neovenator originated in Western Laurasia and eventually gave rise, through dispersal, to the ancestors of Gondwanan carcharodontosaurids. Phylogenetic and biogeographic analysis discusses the time window and possible dispersal corridors between Barremian Europe and Albian South America, including connections via Africa.

Reconstruction by Nobu Tamura (2011) depicting Concavenator corcovatus, published the year after the original description. The species is central to biogeographic discussions on the European origin of carcharodontosaurids.

Scale comparison among multiple carcharodontosaurids, illustrating size differences between the small European Concavenator and Gondwanan giants such as Giganotosaurus and Carcharodontosaurus.

Mateus and Antunes report the presence of the large theropod Torvosaurus in the Late Jurassic of Portugal, one of the ecological predecessors of the large predators that would dominate Europe in the Cretaceous. This work contextualizes the long history of large European theropods: the lineage leading to Concavenator in the Barremian (~130 Ma) has roots in the Iberian Jurassic theropod fauna represented by Torvosaurus and Allosaurus. The Iberian Peninsula was a biodiversity hotspot for large theropods for tens of millions of years, culminating with Concavenator as the last known large European carcharodontosaurid before the dominance of abelisaurids in the Late Cretaceous. The study helps trace the historical biogeography of large European predators and faunal heterogeneity of Western Laurasia during the Mesozoic.

Concavenator corcovatus reconstruction by Nobu Tamura (2011). The animal represents the apex of a long lineage of large Iberian theropods dating to the Jurassic, studied in biogeographic context by works such as Mateus & Antunes (2000).

Fossil of Iberomesornis romerali, a primitive Early Cretaceous bird from Las Hoyas. The same site that produced Concavenator also preserved these primitive birds, indicating a rich avian ecosystem contemporary with the large predator.

Naish and Martill review British dinosaur discoveries and their historical and scientific significance, including Neovenator salerii from the Isle of Wight, the closest known relative of Concavenator and also from the European Early Cretaceous. Neovenator, described in 1996, preceded the discovery of Concavenator and provided the taxonomic context for interpreting the Spanish specimen as a member of a medium-sized carcharodontosaurid fauna that inhabited Western Europe in the Barremian. The relationship between Neovenator and Concavenator is central for reconstructing European carcharodontosaurid biogeography and understanding how the family originated and dispersed worldwide during the Early Cretaceous. The historical work on Neovenator provides essential comparative data for studying Concavenator's anatomy and phylogeny.

Models of Goniopholis, Pelecanimimus, and Concavenator at the Paleontological Museum of Castilla-La Mancha, Cuenca. Neovenator, Concavenator's relative described by Naish & Martill (2007), inhabited the same Early Cretaceous European fauna.

Alternative reconstruction of Concavenator corcovatus. The European carcharodontosaurid context including Neovenator (Naish & Martill, 2007) is essential for understanding the diversity of large predators in the Early Cretaceous of Western Laurasia.

Turner et al. describe quill knobs on the ulna of Velociraptor mongoliensis, the first confirmed occurrence of this structure in a non-avian dinosaur. Quill knobs are ligament attachment bumps that anchor the calamus (quill) of flight feathers to the ulna in modern birds. The discovery in Velociraptor demonstrates that at least some dromaeosaurids had functional (or vestigial) secondary flight feathers despite not flying. This paper is fundamental for understanding Concavenator because the debate over the Spanish carcharodontosaurid's ulnar bumps derives directly from comparison with the structure described by Turner et al. (2007) in Velociraptor. The crucial difference is that dromaeosaurids are much closer to birds than carcharodontosaurids: if Concavenator truly had quill knobs, it would represent a much deeper and more surprising evolutionary record.

Geographic and geological map of the Las Hoyas fossil site (Cuenca, Spain), in the Mesozoic context of the Iberian Ranges. Las Hoyas produced Concavenator and also the dromaeosaurids compared with Velociraptor in Turner et al. (2007).

Field work at the Las Hoyas site in 2018. The same productive site that generated the quill knob debate for Concavenator continues to be excavated, revealing new fossils from the Iberian Barremian.

Full-size T-rex animatronic from the Jurassic Park franchise, with the iconic red Jeep — Amaury Laporte · CC BY 2.0