Nurse shark  (Ginglymostoma cirratum)

Dorsal fins: The unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
Nocturnal: Active at night.
Ovoviviparous: Method of reproduction whereby the egg shell is weakly formed and young hatch inside the female; they are nourished by their yolk sac and then ‘born' live.
Pectoral fins: In fish, the pair of fins that are found one on each side of the body just behind the gills. They are generally used for balancing and braking.
Pharynx: The part of the throat that begins from behind the nose to the beginning of the oesophagus and trachea, or windpipe.

1. IUCN Red List (September, 2007)
   http://www.iucnredlist.org
   
2. Compagno, L.J.V. (2001) Sharks of the World. An annotated and illustrated catalogue of shark species known to date. Vol. 2: Bullhead, mackerel and carpet sharks (Heterodontformes, Lamniformes and Orectolobiformes). Food and Agriculture Organization of the United Nations, Rome.
   
3. Ferrari, A. and Ferrari, A. (2002) Sharks. Firefly Books Ltd, Toronto, Canada.
   
4. Carwardine, M. and Watterson, K. (2002) The Shark Watcher's Handbook. BBC Worldwide Ltd, London.
   
5. Nurse Shark Biological Profile, Ichthyology Department, Florida Museum of Natural History (September, 2007)
   http://www.flmnh.ufl.edu/fish/Gallery/Descript/nurseshark/nurseshark.htm
   
6. Carpenter, K.E. (2002) The living marine resources of the Western Central Atlantic. Volume 1: Introduction, molluscs, crustaceans, hagfishes, sharks, batoid fishes, and chimaeras. Food and Agriculture Organization of the United Nations, Rome.