Pronunciation: TRO-meh-ro-SOR-us
Meaning: Frightful lizard
Author/s: Powers et al. (2026)
Synonyms: None known
First Discovery: Alberta, Canada
Acta Ordinal: #1252
Tromerosaurus solumons
(Frightful Lizard of the Lonely Mountain Etymology
Tromerosaurus combines the Greek "tromeros" (frightful, terrible, alarming) with "sauros" (lizard), alluding to the blend of features seen in two of its close relatives, Daspletosaurus ("frightful lizard") and Gorgosaurus ("terrible lizard").
The species epithet, solumons (SOH-loo-mons), is derived from the Latin "solus" (lonely) and "mons" (mountain), referring to the bony boss or "horn" in front of the eyes that stand apart from surrounding structures, giving the impression of a solitary peak (a "lonely mountain"), and is a deliberate nod to Smaug's home, the Lonely Mountain (Erebor) in The Hobbit, hinting at the similarities in appearance between Tolkien's dragons and tyrannosaurids.
Discovery
The name-bearing specimen of Tromerosaurus was discovered at quarry Q258 in the Oldman Formation, Dinosaur Provincial Park, Alberta, Canada, by Dr. S. Plotkin of Stony Brook, NY, in 2010, and excavated by a crew from the University of Alberta in 2010 and 2011.
The holotype (UALVP 52981) is a partial skeleton and beautifully-preserved skull.
Four more specimens were also referred to Tromerosaurus: TMP 1994.012.0602 (much of the skull and tail, belly ribs, most of both hindlimbs and the pelvic girdle) that was previously regarded as the largest and oldest specimen of Gorgosaurus libratus, TMP 1995.005.0001 (the partial, disarticulated skull and unprepared pelvis of a smaller individual), and UALVP 56605 and TMP 1985.011.0003 (two tooth-bearing bones of the upper jaw), one from an adult, the other from a small juvenile, the latter of which was assigned to Albertosaurus libratus by Carr in 1999.
Preparators
University of Alberta Laboratory for Vertebrate Paleontology (UALVP) volunteer B. Szafron.
