Losillasaurus (meaning "Losilla lizard") is a genus of turiasaurian sauropod dinosaur from the Late Jurassic and possibly Early Cretaceous (Kimmeridgian-?Berriasian) of southeastern Spain. It is also known from the Lourinhã Formation of Portugal. The type species, Losillasaurus giganteus, was discovered in the Villar del Arzobispo Formation in Valencia, and formally described by Casanovas, Santafé, and Sanz in 2001. The holotype material is from a subadult and includes part of a skull; complete cervical, dorsal, sacral, and caudal vertebrae as well as several fragments; skeletal elements from the limbs including a humerus, ulna, radius, and metacarpal; sternal plates; and from the pelvis: the ilium, ischium, and pubis. The genus is characterized by the dimension and shape of the neural spine of the proximal caudal vertebrae.Ruiz-Omeñaca, Jose Ignacio (2001). "Losillasaurus giganteus, a new Spanish sauropod". Dinosaur Mailing List.
Description
Several specimens of L. giganteus were described in 2019 and 2020 - one such specimen (SHN 180) consists of a single anterior caudal vertebra, while another (the holotype) consists of a partial skull with teeth and partial postcranial skeleton.Campos-Soto S, Benito MI, Cobos A, Caus E, Quijada IE, Suarez-Gonzalez P, Mas R, Royo-Torres R, Alcalá L. 2019. Revisiting the age and palaeoenvironments of the Upper Jurassic–Lower Cretaceous? Dinosaur-bearing sedimentary record of eastern Spain: implications for Iberian palaeogeography. Journal of Iberian Geology 45: 471–510. According to Rafael Royo-Torres et al., the specimen helps scientists to understand tooth variation, allows the positioning of isolated heart-shaped teeth in the skull and demonstrates heterodonty in Turiasauria. The humerus is long,Ruiz-Omeñaca, Jose Ignacio (2001)."Re: Losillasaurus giganteus, a new Spanish sauropod". Dinosaur Mailing List. which despite being from a subadult specimen is within 20% of the size of Paralititan.Taylor, Mike (2001). "Re: Losillasaurus giganteus, a new Spanish sauropod". Dinosaur Mailing List The size estimation proposed by Francisco Gascó in his master thesis is in length and in body mass.Gascó, F (2009): Sistemática y anatomía funcional de Losillasaurus giganteus Casanovas, Santafé & Sanz, 2001 (Turiasauria, Sauropoda). Universidad Autónoma de Madrid. However as the type specimen is not fully grown, adult Losillasaurus likely grew bigger. A giant referred specimen has a femur length of ,a tibia length of and a humerus length of suggesting an animal that was similar in size to Turiasaurus. The largest Losillasaurus would have measured in length and weighed about .
References