Since these contributions, saponins have been isolated from numerous species of Aspidochirotida
and Dendrochirotida and also from sea stars (Mackie and Turner, 1970; Kitagawa and Kobayashi, 1977; Demeyer et al, 2014).
From Pakistan total 11 genera and 14 species of sea cucumbers have been recorded belonging to the orders Aspidochirotida
and Dendrochirotida to which most of the commercial species belong.
There is a huge diversity of species of sea cucumbers (66 species) that are harvested commercially and traded around the world, with the majority of these species belonging to the order Aspidochirotida
, and only a few to the order Dendrochirotida (Purcell et al.
Grube, 1840 Familia Holothuriidae Ludwig, 1894 Genero Holothuria Linnaeus, 1767 Subgenero Thymiosycia Pearson, 1914 Holothuria (Thymiosycia) arenicola (Semper, 1868) Familia Stichopodidae Haeckel, 1896 Genero Isostichopus Deichmann, 1958 Isostichopus fuscus (Ludwig, 1874)
Phylum Echinodermata Class Holothuroidea Order Aspidochirotida
Previous studies on the auricularia serotonergic system involved the larvae of Parastichopus californicus and Stichopus japonicus, members of the order Aspidochirotida
(4, 7, 11).
Several species of holothuroids (sea cucumbers), all belonging to the order Aspidochirotida
, possess a very specialized defensive system: the so-called Cuvierian tubules (Flammang, 1996).
Evidence for the tubule recruitment model was limited to holothurians of the orders Aspidochirotida