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| Llukalkan aliocranianus Gianechini, Méndez, Filippi, Paulina-Carabaja, Juárez-Valieri & Garrido, 2021 |
ABSTRACT
Abelisaurids are among the most abundant and diverse Patagonian Late Cretaceous theropods. Here, we present a new furileusaurian abelisaurid, Llukalkan aliocranianus gen. et sp. nov., represented by cranial remains from the Bajo de la Carpa Formation (Santonian) at La Invernada fossil area, northwestern Patagonia. Features characterizing this taxon include a possible caudal tympanic recess posterior to the columellar recess, a T-shaped lacrimal with jugal ramus lacking a suborbital process, and large foramina for caudal middle cerebral veins widely separated from the median supraoccipital crest. In addition to this, a bulge on the anteromedial border of the supratemporal fossa, tall and posteriorly projected paroccipital processes, basal tubera interconnected distally, a triangular basisphenoid recess, and a single foramen for the sphenoidal artery on the basisphenoid, differentiate Llukalkan from Viavenator exxoni. The latter is the other furileusaurian taxon from the same area and stratigraphic unit. Although the holotype of Llukalkan probably corresponds to a sub-adult—as the lacrimal morphology suggests— the possibility that it represents a juvenile of V. exxoni is discarded based mainly on the presence of a caudal tympanic recess (which is absent in V. exxoni). The probable coexistence of two abelisaurid taxa demonstrates that the abelisaurids were one of the most important—and likely the main—predator component of the ecosystems, not only in this area, but also in all of Patagonia, during the Late Cretaceous.
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| FIGURE 17. Reconstruction of the complete skull and mandible of Llukalkan aliocranianus, from the Late Cretaceous of Neuquén Province, Argentina, in left lateral view. The preserved bones are located in their supposed natural positions, whereas non-preserved parts and bones are in gray. The prearticular bone has a medial location, laterally covered by the angular and surangular. The maxilla, jugal and quadrate correspond to the right side, although they were mirrored to accommodate with the image. Scale bar equals 5 cm. For abbreviations in the figure, see text. |
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| FIGURE 1. Provenance of the holotype of Llukalkan aliocranianus (MAU-Pv-LI-581). A, map showing the location of La Invernada fossil area; B, photograph of the materials in situ in the field; C, photograph showing the aspect of the outcrops of the Bajo de la Carpa Formation at La Invernada fossil area (indicated with the arrow). |
SYSTEMATIC PALEONTOLOGY
THEROPODA Marsh, 1881
CERATOSAURIA Marsh, 1884
ABELISAURIDAE Bonaparte and Novas, 1985
BRACHYROSTRA Canale, Scanferla, Agnolin and Novas, 2009
FURILEUSAURIA Filippi, Méndez, Juárez Valieri and Garrido, 2016
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| Llukalkan aliocranianus. Illustration: Jorge Blanco. |
LLUKALKAN ALIOCRANIANUS gen. et sp. nov.
Etymology— Llukalkan, means “one who scares or causes fear” in Mapudungun; aliocranianus means “different skull” in Latin.
Federico A. Gianechini, Ariel H. Méndez, Leonardo S. Filippi, Ariana Paulina-Carabaja, Rubén D. Juárez-Valieri and Alberto C. Garrido. 2021. A New Furileusaurian Abelisaurid from La Invernada (Upper Cretaceous, Santonian, Bajo De La Carpa Formation), Northern Patagonia, Argentina. Journal of Vertebrate Paleontology. e1877151. DOI: 10.1080/02724634.2020.1877151
The 'one who causes fear'—new meat-eating predator discovered
