Dynamoterror (meaning "powerful terror") is a monospecific genus of tyrannosaurid dinosaur from New Mexico that lived during the Late Cretaceous (lower Campanian stage, 78 Ma) in what is now the upper Allison Member of the Menefee Formation. The type and only species, Dynamoterror dynastes, is known from a subadult or adult individual about 9 metres (30 feet) long with an incomplete associated skeleton. It was named in 2018 by Andrew T. McDonald, Douglas G. Wolfe and Alton C. Dooley, Jr.[1] Dynamoterror was closely related to Teratophoneus and Lythronax.[2]
In August 2012, a partial skeleton of a tyrannosaurid was discovered, and later collected, from the Lower Campanian Allison Member of the Menefee Formation in the San Juan Basin of northwestern New Mexico. The remains were found by geology students Brian Watkins and Eric Gutiérrez on an expedition led by Andrew McDonald of the Western Science Center, and Douglas Wolfe, the CEO of the Zuni Dinosaur Institute for Geosciences. Subsequent expeditions at the Menefee Formation in 2013 and 2018 did not reveal any additional elements. The specimen was subsequently named and described in 2018 by Andrew T. McDonald, Douglas G. Wolfe and Alton C. Dooley, Jr. The holotype specimen, UMNH VP 28348, consists of the left and right frontals, fragmentary vertebral centra, fragments of dorsal ribs, right metacarpal II, supraacetabular crest of the right ilium, phalanx 2 of left pedal digit IV, phalanx 4 of left pedal digit IV, and other unidentifiable bone fragments. The holotype specimen is currently housed at the Natural History Museum of Utah, Salt Lake City, Utah.[1]
The generic name, Dynamoterror, is derived from the Greek word "dynamis" (power) and the Latin word "terror". The specific name, dynastes, is derived from the Latin word "dynastēs" (ruler). The binomial name honours “Dynamosaurus imperiosus”, a junior synonym of Tyrannosaurus, as it had been a "childhood favourite" of one of the authors.[1]
In 2020, Chan-gyu Yun considered Dynamoterror a nomen dubium due to the highly fragmentary nature of the holotype specimen and lack of autapomorphies as two of the original autapomorphies are present in other tyrannosaurids. Additionally, the fragmentary nature of the frontal makes it uncertain whether the autapomorphies are even comparable to other tyrannosaurids.[3]
In 1993, Adrian P. Hunt and Spencer G. Lucas reported tooth fragments and a metatarsal of a tyrannosaurid from the Menefee Formation, and in 2006, Lewis et al. reported another tooth fragment.[1][4] McDonald et al. (2018) suggested that, due to the lack of overlapping material, the previously reported tyrannosaurid material could not be referred to Dynamoterror.[1] In 2018, Sebastian G. Dalman and Spencer G. Lucas described five tyrannosaurid specimens from the Menefee Formation: NMMNH P-8313, a right anterior scapula; NMMNH P-22133, a metatarsal II; NMMNH P-61274, a shaft of an anterior thoracic rib; NMMNH P-71332, a lateral tooth; and NMMNH P-78032, a left postorbital.[5]
A more complete specimen of Dynamoterror was identified in 2021,[6] but has not yet been described in detail. It is known as specimen WSC 1027 and is also from the Menefee Formation.[6]