Holy F’n 2-Headed Shark Batman!

Screen Shot 2013-03-26 at 7.53.46 PMWell I just found new fodder for my nightmares. The two-headed fetus was removed from a pregnant female captured in the Gulf of Mexico near Key West, Florida, U.S.A. by a commercial fishing vessel (F/V Island Girl) on 7 April 2011.  According to the authors of the recent study describing this anomaly.

Each head has five pairs of gills and gill openings, a single pair of eyes, a single pair of nares and a mouth with well-developed dentition. The teeth appear both normally formed.

Apparently, dicephalia (two-headed) is rare in sharks (or rarely reported anyway).  Besides the bullshark here, previous reports include the Squalus acanthias, longnose spurdog Squalus blainville, milk shark Rhizoprionodon acutus, blue shark Prionace glauca, and the tope shark Galeorhinus galeus. Total hat tip to David Shiffman, aka Mr. Shark, aka purveyor of weird, aka moncephalic scientists, aka @whysharksmatter Screen Shot 2013-03-26 at 7.53.54 PM

C. M. Wagner, P. H. Rice and A. P. Pease First record of dicephalia in a bull shark Carcharhinus leucas (Chondrichthyes: Carcharhinidae) foetus from the Gulf of Mexico, U.S.A. Journal of Fish Biology 25 MAR 2013 | DOI: 10.1111/jfb.12064

Dr. M (1720 Posts)

Craig McClain is the Assistant Director of Science for the National Evolutionary Synthesis Center, created to facilitate research to address fundamental questions in evolutionary science. He has conducted deep-sea research for 11 years and published over 40 papers in the area. He has participated in dozens of expeditions taking him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses mainly on marine systems and particularly the biology of body size, biodiversity, and energy flow. He focuses often on deep-sea systems as a natural test of the consequences of energy limitation on biological systems. He is the author and chief editor of Deep-Sea News, a popular deep-sea themed blog, rated the number one ocean blog on the web and winner of numerous awards. Craig’s popular writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.