This chimera species, a Deep-Sea Chimaera, was found about 4200 feet below the ocean at abyssal depths.

NOAA Ocean Explorer, CC BY-SA 2.0, via flickr

NOAA Ocean Explorer, CC BY-SA 2.0, via flickr

A cousin of  sharks and rays, it is one of the world’s oldest species of fish.  It goes by a number of aliases including ratfish, rabbitfish and ghostshark.  It branched off from the shark family, its closest relative, about 400 million years ago.  It has remained relatively unchanged since it shared the Earth with the dinosaurs.  Like sharks, they have a skeleton made of cartilage.  Because they live in the deep, dark ocean abyss, they are poorly studied and understood.

This particular species of Hydrolagus has lateral lines running across its body.  These lines are mechano-receptors that detect pressure waves (think ears). The dotted-looking lines on the front of the face of the deep-sea chimaera (near the mouth) are ampullae de lorenzini.   This organ detects disturbances in electrical fields produced by living organisms. Through these mechano-receptors, the chimera can locate prey and mates in the darkness of its habitat.  For defense, most chimaeras have a venomous spine in front of the dorsal fin used as a defense mechanism

It is amazing that as our technology grows to explore ever deeper ocean depths, the range and complexity of our biosphere is revealed.  More will be learned about these elusive, deep-sea creatures as our ability to observe them in their natural habitat improves.  I am excited to see what more is left to be discovered.

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