PSEUDOTRIAKIDAE FALSE CATSHARKS AND GOLLUMSHARKS
Common Name– Ground Sharks
Pseudotriakidae are a small family of belonging to the order Carcharhiniformes, or Ground sharks. This family includes the False catsharks (genera Pseudotriakis and Planonasus) and Gollumsharks (genus Gollum). It contains the only ground shark species that exhibit intrauterine oophagy, in which developing fetuses are nourished by eggs produced by their mother. One undescribed species is known, Gollum sp. B or the Whitemarked Gollumshark.
These sharks are small to large and bulky in size ranging from 56-295 cm/1.8-9.7 feet. They seem to be soft-bodied. They have narrowly rounded heads and a somewhat bell-shaped and elongated snout. The eyes are cat-like and elongated, and there is a deep groove in front of them, and large spiracles behind. They have nictitating membranes. There are no barbels or nasoral grooves. The internarial space is over 1.5 times the nostril width. The mouth is arched, long and angular that reaches past the anterior ends of the eyes. There are numerous small cuspidate teeth in 200 or more rows in each jaw. There aren’t papillae in the mouth or on the edges of the gill arches. The labial arches are present, but short. The first dorsal fin is elongated, and the base is closer to the pectoral fin bases rather than the pelvic fin bases. It is low and keel-like. The caudal fin has a weak ventral lobe, or no ventral lobe. There are no precaudal pits. There are no lateral undulations on its dorsal margin. The color is usually plain grey to brown or even blackish in color. Some of the Gollum species have white spots and fin margins.
These sharks are ovoviviparous from what is known today. Scientists know that at least two species are oophagous, being the fetuses eat the eggs nourished by the mother. They more than likely have litters of 2 to possibly 4 young. More than likely they feed on a variety of deep-water bony fishes, elasmobranchs and invertebrates.
Pseudotriakidae are deep-water sharks that are found on the outer continental and insular shelves and slopes on or near the bottom between 423-6,201 feet. The False catshark is actually a wide-ranging, small shark that is restricted in the western Indian Ocean and western Pacific Ocean. They are absent from the south Atlantic and eastern Pacific. Some of these sharks are found from Madagascar to Taiwan and Hawaii, and to Iceland.
Dwarf False Catshark– Planonasus parini (Weigmann, Stehmann & Thiel, 2013)
False Catshark or Sofa Shark– Pseudotriakis microdon (de Brito Capello, 1868)
Pygmy False Catshark or Eastern Dwarf False Catshark– Planonasus indicus
Slender Smoothhound or Gollumshark– Gollum attenuatus (Garrick, 1954)
Sulu Gollumshark– Gollum suluensis (Last & Gaudiano, 2011)