A ghost shark, or chimaera, was captured on camera by the Monterey Bay Aquarium Research Institute in California and published by National Geographic.
The video was obtained by a remotely operated vehicle in 2009, as it went 6,700 feet deep to analyze geological formations. The encounter with the evasive shark-like species was noted as a result of pure luck.
The geologists provided the footage to shark experts and confirmed that the specimen was a pointy-nosed blue chimaera (Hydrolagus trolli), which is usually found in the waters of Australia and New Zealand.
According to researchers, chimaeras set themselves apart from sharks and rays 300 million years ago, existing even before dinosaurs. Regardless of this fact, chimaeras remain largely unexamined, and the latest footage allowed to see one swimming around in its natural habitat, in the deep waters of Central California.
Ancient sea creatures
Chimaeras live exclusively on ocean floors, some being spotted 8,500 feet deep, although there are minor exceptions such as the spotted ratfish that is native to the northern coasts of California. Unlike sharks, chimaeras do not have sharp teeth, being replaced by plates, and they also have their gills covered by a hard flap, native to fishes whose skeletons are made out of bone. They also have canals on their heads that let them sense water currents, allowing them to hunt in the absence of light.
These species earned the name due to their unusual anatomy. Chimaeras in Greek mythology were monstrous hybrid creatures, usually a lion with a goat’s head on its back and a snake’s tail.
There is very little information about how these species has evolved due to the lack of fossils, although the variety of specimens has been noted thoroughly, adding up to 50 extant species.
“The presence of Hydrolagus cf. trolli increases the number of known Hydrolagus species to three off California, and to two species off the Hawaiian Islands. Our specimens cannot yet be confirmed as Hydrolagus trolli until morphometric data and or DNA samples from preserved specimen have been collected and analyzed,” wrote the researchers in their study.
Using the footage, experts identified the specimen, although they cannot be entirely sure of its classification unless they obtain a DNA sample from the fish itself. The main problem is that it is almost impossible to retrieve chimaeras to the surface without them dying in the process.
Despite the obstacles, experts could learn from the footage that pointy-nosed blue chimaeras do not always reside on the sea floor, where other chimaera species are known to spend their time.
Researchers published their views on a report in the Marine Biodiversity Records to account for the finding of a chimaera specimen, being highlighted as the first time a Hydrolagus trolli is spotted in the central and eastern North Pacific Ocean.
The species is named in the report as a Hydrolagus cf. trolli, and the “cf.” stands for “conferre,” a Latin word meaning “compare to.” This suggests that researchers are not completely sure that the specimen filmed was indeed a pointy-nosed blue chimaera, although its characteristics match the official description of one.
Source: MBARI