Genus: Grendelius McGOWAN, 1976
Etymology: For Grendel, a monster in the Beowulf epic, who came from he Fens in the Region of the Oxford Clas, England, where the fossil was found.

Species: alekseevi (ARKHANGELSKY, 2001 ZVERKOV, ARKHANGELSKY, & STENSHIN, 2015
Etymology: In honor of the late geologist A. V. Alekseev from Ulyanovsk.
= Otschevia alekseevi ARKHANGELSKY, 2001

Holotype: Ulyanovsk Regional Musum, YKM (old URM) 56702

Locality: Right bank of the Volga River, 18 km north of Ulyanovsk, Ulyanovsk District, Ulyanovsk Region, European Russia.

Horizon:

Biostratigraphy: Dorosplanites panderi Zone.

Age: Volgian, Tithonian Stage, Malm Epoch, Late Jurassic.

Material: Fragmentary skull, humeral girdle, forelimbs, vertebral column (60 vertebrae) and ribs.

Note: It has a broken clavicle with pseudarthrosis and abcesses (PARDO-PEREZ, KEAR, GOMEZ, MORONI & MAXWELL, 2018).