The Pseudotriakidae are a small

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

ground shark Carcharhiniformes , the ground sharks, are the largest order of sharks, with over 270 species. They include a number of common types, such as catsharks, swellsharks, and the sandbar shark. Members of this order are characterized by the presence ...

s, belonging to the order

Carcharhiniformes Carcharhiniformes , the ground sharks, are the largest order of sharks, with over 270 species. They include a number of common types, such as catsharks, swellsharks, and the sandbar shark. Members of this order are characterized by the presenc ...

, containing 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

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal dev ...

es are nourished by eggs produced by their mother.

Undescribed species

One undescribed species is known - one in the genus ''Gollum'', (''Gollum'' sp. B) - the white-marked gollumshark.Weigmann, S., Stehmann, M.F.W. & Thiel, R. (2013): ''Planonasus parini'' n. g. and n. sp., a new genus and species of false cat sharks (Carchariniformes, Pseudotriakidae) from the deep northwestern Indian Ocean off Socotra Islands. ''Zootaxa, 3609 (2): 163–181.''

References

Shark families Taxa named by Theodore Gill {{Shark-stub