Pronunciation: ter-mih-no-KAY-vus
Meaning: Closing cavity
Author/s: Fowler and Freedman Fowler (2020)
Synonyms: None known
First Discovery: New Mexico, USA
Acta Ordinal: #1032
Terminocavus sealeyi
(Sealey's Closing Cavity)Etymology
Terminocavus is derived from the Latin "terminus" (end), interpreted in this case as "coming to the end (or "last stop for", as in a train terminus), and "cavus" (cavity, hollow), referring to the nearly closed parietal embayment—the small, central notch along the back edge of a horned dinosaur's frill. According to Fowler and Freedman Fowler, Pentaceratops — Navajoceratops — Terminocavus — Anchiceratops represents an anagenetic sequence (a straight?line evolutionary series in which each form gradually evolves into the next), with the embayment gradually shrinking over time, and Terminocavus being the last in line before it closes entirely in Anchiceratops. The species epithet, sealeyi, honours Paul Sealey who discovered the holotype specimen.
ZooBank registry: urn:lsid:zoobank.org:act:6E5A8D79-1F2C-484F-BED7-7C556C5C062A.
Discovery
The remains of Terminocavus were discovered in the Hunter Wash Member of the Kirtland Formation, San Juan Basin of New Mexico, by Paul Sealey in 1997.
The holotype (NMMNH P-27468) is an incomplete skull, partial sacrum, and vertebral fragments. It was previously mentioned in an abstract by Sealey, Smith and Williamson in 2005, where it was identified as a specimen of Pentaceratops sternbergii. A nearly complete skull (PMU 24923, previously PMU R200), found by Charles H. Sternberg in 1921 in the Kirtland Formation of New Mexico and named Pentaceratops fenestratus by Wiman in 1930, may belong to Terminocavus, or maybe to Pentaceratops sternbergi. Unfortunately, it's too distorted to confidently refer to anything.
