Weird bat ray — Mutilated when young? Genetic abnormality? Conjoined twins?

[Ken Jones]

Hans (Sofa King) sent me this picture of a fish caught by Frank L. It appears to be a misformed bat ray or perhaps it was mutilated at some point? I sent a note to Milton Love at UCSB asking if he had any ideas. Below is a normal bat ray and also a picture of an angel shark (which some thought it was).

Below, a normal bat ray that I caught one day in Oakland.





Angel Shark caught by GordoGrande (Ross Kestin) at the Avila Pier
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[mjonesjr]

Ken I saw that a few days ago when it was caught. Can’t wait to hear the feedback you get from your inquiry.

 

[Makairaa]

Looks like two embryos combined into one. Conjoined twins. Too perfect of symmetry to be mutilated.

 

[Makairaa]

Underside photo of the same ray.

 

[Ken Jones]

Feedback from Dr. Love indicates it's a mystery. He did say, "the symmetric nature kind of says genetic abnormality."

Very interesting.

 

[beutelevision]

I bet it has extra vertebrae. Would be interesting to see an X-ray.

 

[Ken Jones]

It's hard to say what would show up in an x-ray. Sharks and rays do not have a typical bone skeleton but have cartilage instead of bone. It's why they are placed in a separate class, Chondrichthyes (cartilaginous fish), instead of being placed in the class Osteichthyes (bony fish).

 

[EgoNonBaptizo]

One potential argument against it being a mutation is the lack of a free trailing edge, which I would expect to have formed if there was indeed some kind of duplication mutation or a parasitic twin. The torso does seem longer in proportion to the head than in a normal bat ray. An x-ray would still likely show any changes to the internal skeleton, since a neoselachian (the larger clade containing sharks and rays) synapomorphy (derived trait) is calcified vertebral centra.

 

[billzerkeley]

I'm guessing the fish only put up half the fight...

 

[The Happy Wanderer]

So what happened to the fish? Was it returned to the water?

 

[Makairaa]

So what happened to the fish? Was it returned to the water?

Released as far as I have heard.

 

[Ken Jones]

I hope it was released although I am pretty sure the scientists like Dr. Love would have liked to study it.