Cephaloscyllium

Cephaloscyllium is a genus of catsharks, and part of the family Scyliorhinidae, commonly known as swellsharks because of their ability to inflate their bodies with water or air as a defense against predators. These sluggish, bottom-dwelling sharks are found widely in the tropical and temperate coastal waters of the Indian and Pacific Oceans. They have stocky, spindle-shaped bodies and short, broad, and flattened heads. The mouth is capacious, containing many small teeth and lacking furrows at the corners. The two dorsal fins are placed far back on the body, with the first much larger than the second. Different species have various color patterns of saddles, blotches, reticulations, and/or spots. The largest members of the genus can grow over 1 m (3.3 ft) in length. Swellsharks prey on a variety of fishes and invertebrates, and are oviparous, with females producing egg capsules in pairs. They are harmless and have been deemed of having no commercial value. The genus Cephaloscyllium was proposed by American ichthyologist Theodore Gill from the Greek kephale ('head') and skylion ('dogfish'), in an 1862 issue of Annals of the Lyceum of Natural History of New York. However, most of Gill's contemporaries, particularly those in Europe, preferred to keep the swellsharks within the genus Scyllium (a synonym of Scyliorhinus). Cephaloscyllium did not gain wide acceptance until Samuel Garman published 'The Plagiostomia' in a 1913 volume of Memoirs of the Museum of Comparative Zoology, in which he recognized three species: C. isabellum, C. ventriosum, and C. umbratile. A long history of taxonomic confusion exists regarding the species within Cephaloscyllium owing to several factors, including variation in appearance (particularly between juveniles and adults), the existence of multiple undescribed species, a paucity of detailed scientific descriptions and type material, and the use of unreliable characters. Until recently, various authors had recognized five to eight species, along with at least five undescribed species in Australian waters and more in the western central Pacific and the Indian Ocean. In 2008, significant strides were made in resolving the taxonomy of Cephaloscyllium, with a revision of the genus and an increase in the number of described species to 21.