Timorebestia

Timorebestia koprii is an extinct species of stem-group chaetognath (arrow worm relative) that lived about 520 million years ago, in the Cambrian. Its fossils are known from the Sirius Passet Lagerstätte in Greenland, and it was first described in 2024.

== Description == Timorebestia has a wide body marginally surrounded by continuous rayed fins: a pair of lateral fins and a rounded caudal fin. The anterior region is a short head, bearing a pair of antennae as long as half of the body length. The mouth opened below the head, with internal jaw apparatus consisting of paired subtriangular elements, blunt anterior elements, and an unpaired anterior, possibly ventral or basal plate. Rows of longitudinal and transverse muscles surround the wide trunk region. The digestive tract terminates at the base of caudal fin. It also has a pair of well-defined ventral ganglia that identifies it as a chaetognath, but was probably more basal to modern arrow worms than Amiskwia.