A hypertrophied ungual phalanx from the lower Barremian of Spain: Implications for the diversity and palaeoecology of Spinosauridae (Theropoda) in Iberia

Abstract

An enlarged theropod manual ungual (CSC1-4) from the Weald facies of Spain is described. The claw was found in the fossil locality of Caña Seca 1, Teruel province, within the El Castellar Formation of early Barremian (Early Cretaceous) in age. CSC1-4 is morphologically closer to megalosauroids than to any other theropod clade bearing enlarged manual claws and shows the greatest similarity to the manual ungual of digit I of Baryonyx walkeri. Both CS1-4 and this taxon share a particularly enlarged, elongated and transversely wide manual claw. CSC1-4, however, differs from Baryonyx´s ungual in having less curvature, a straight dorsal edge in the proximal part, slightly more width above the grooves than below, and a certain asymmetry, with the lateral face more flattened. Taking into account the paleogeographic and temporal context, these considerations suggest that they are closely related but distinct spinosaurid taxa. The presence of an enlarged manual claw in spinosaurids has been invoked as an anatomical feature typically associated with scavenging and hunting habits, as well as digging behaviour. The spinosaurid record from the Barremian of the Iberian Peninsula shows that members of this clade favored freshwater environments with some marine influence in this part of Europe.

New spinosaurids from the Wessex Formation (Early Cretaceous, UK) and the European origins of Spinosauridae

“…Spinosaurids did exhibit heterodonty, but the discovery of these new Wessex Fm. baryonychines, coupled with the occurrence of at least two taxa and multiple dental morphotypes (representing baryonychines and spinosaurines) from the Early Cretaceous deposits of the Iberian Peninsula [58][59][60][61][62] , paints a more complex picture. Diagnostic Iberian taxa from the Barremian specifically include Baryonyx, Vallibonavenatrix and possibly Camarillasaurus (see below), though their remains currently occur in non-overlapping formations and the true taxonomic diversity of the Iberian sample remains elusive 61,62 .…”

A new theropod dinosaur from the early cretaceous (Barremian) of Cabo Espichel, Portugal: Implications for spinosaurid evolution

“…Only new material from Camarillasaurus would confirm its placement with greater detail in the spinosaurid family tree [ 7 ]. The material traditionally assigned to Baryonyx from the Iberian Peninsula, as the specimen from Sala de Los Infantes [ 35 ], needs revision in light of this recent work that suggests a complex scenario between the Iberian spinosaurids in general and the baryonychines in particular [ 37 , 39 ]. Although as previously shown, isolated elements such as claws, teeth and appendicular bones already hinted at a hidden diversity within this clade.…”

“…Shortly after the discovery of Baryonyx , a series of papers referred several isolated elements to this taxon from Spain, including a left maxilla [ 34 ] and a partial vertebral column and forelimb [ 35 ]. In addition, some isolated teeth and a hypertrophied manual ungual phalanx were attributed to baryonychine theropods [ 36 , 37 ] along with several isolated teeth referred to spinosaurines [ 38 , 39 ]. The first taxon of Spinosauridae described from the Iberian Peninsula, Vallibonavenatrix cani Malafaia et al, 2020 [ 6 ], was established on the basis of cervical, dorsal, sacral, and caudal elements, with fragments of ribs, chevrons, and a relatively complete pelvic girdle; their analysis placed it within Spinosaurinae.…”

Fast-running theropods tracks from the Early Cretaceous of La Rioja, Spain

“…Medium-sized theropods from the Early Cretaceous of the Iberian Peninsula include the following three groups. (1) Spinosaurids have been identified in the Early Cretaceous of Iberia on the basis of isolated teeth 28 , 37 – 41 and skeletal remains 42 – 45 , Vallibonavenatrix cani being the only spinosaurid genus and species described to date 46 . (2) Carcharodontosaurids are known in several Early Cretaceous localities by teeth 40 and skeletal remains 47 ; the only genus and species currently described is the iconic Concavenator corcovatus 48 , 49 .…”