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

Ken Jones

Administrator
Staff member
#1
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).

unnamed.jpg

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

Bat.Ray_Fortman.Marina.Pier_2012.2.JPG

Angel.Shark_Avila.P_2008_Ross copy.jpg

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

Ken Jones

Administrator
Staff member
#5
Feedback from Dr. Love indicates it's a mystery. He did say, "the symmetric nature kind of says genetic abnormality."

Very interesting.
 

Ken Jones

Administrator
Staff member
#7
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

Well-known member
#8
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.