A new species of ghostsharks, a relative of sharks, was recently named. Ghostsharks (also called chimaeras, ratfish or rabbitfish) are some of the oldest fish alive today. The name of the newly identified but ancient species is Eastern Pacific black ghostshark.
Chimaeras or Ghostsharks
The group this new fish belongs to might be the oldest group of fish alive today, and also one of the least understood. Sharks are the closest living relatives, but the two groups are believed to have split about 400 million years ago.
As ScienceDaily reports: “Unlike sharks, male chimaeras also have retractable sexual appendages on the forehead and in front of the pelvic fins and a single pair of gills. Most species also have a mildly venomous spine in front of the dorsal fin.”
Apparently, chimaeras were very diverse and abundant ages ago — they have a “global presence in the fossil record” — and lived through the age of dinosaurs with few changes. However, they are fairly scarce these days. Due to this, and the fact that they live in deep waters, scientists still know little about them.
Eastern Pacific Black Ghostshark
The Eastern Pacific black ghostshark (Hydrolagus melanophasma) lives off the coast of California and Baja California (Mexico) and in the Sea of Cortez (which is in the Gulf of California). It is in the genus Hydrolagus (“water rabbit”), which are named this because they have tooth plates similar to rabbits’ incisor teeth. The Eastern Pacific black ghostshark is large and blackish-purple.
Although this ghostshark was originally discovered in the 1960s, it was just named and “described” because scientists were not sure of its taxonomic relations previously. It is rarely seen alive because it lives in very deep waters.
More information on the new species is in the September issue of Zootaxa.
Image Credit: lscott2dog via flickr under a Creative Commons license