Ceriantipatharia

Ceriantipatharia is a deprecated order of corals within the class Hexacorallia, ^[1] although it was initially considered as a subclass in older taxonomies.^[2] It was split and it is now replaced by its previous two constituent orders, Ceriantharia (tube-dwelling anemones) and Antipatharia (black corals).

Ceriantipatharia
Cerianthus sp., an example of Ceriantharia.
Black coral colony, an example of Antipatharia
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Cnidaria
Subphylum:	Anthozoa
Class:	Hexacorallia
Order:	Ceriantipatharia Van Beneden, É., 1898

History and importance as a subclass (now an order) of Hexacorallia ^[3]

Since its definition by Édouard Van Beneden, in 1897, ^[4] until its deprecation c. 2007, it remained an important taxon due to its high rank (subclass) in the taxonomy of Cnidaria, profusely cited in the scientific bibliography and studied by scientists like the paleontologists Dorothy Hill and John W. Wells, ^[5] and the marine biologist J. E. N. Veron, ^[6] among many others.

Van Beneden considered that the similarities in morphology between the larva of the cerianthids (which he called cerinula, portmanteau of cerianthid and planula) and the antipatharian polyp were the main reason for separating the orders Ceriantharia and Antipatharia from the other Hexacorallia orders, and group them as a distinct subclass, Ceriantipatharia.^[4]

Unlike van Beneden, in volume I (Porifera through Ctenophora) of her six-volume treatise The Invertebrates (1940), Hyman did not group together the orders Ceriantharia and Antipatharia. Nor was Ceriantipatharia mentioned, even though she cited van Beneden in the bibliography for each of those orders (ps.660-661).^[7] The reason could be that, as she states in the preface, she followed mainly the German school of zoologists. Her treatise was based on Bronn's Klassen und Ordnungen des Tierreichs (1862), edited before van Beneden's definition of Ceriantipatharia, and on Kükenthal-Krumbach's Handbuch der Zoologie (1923), that she considered "the most extensive modern treatise on zoology" (p.31). In the latter treatise, van Beneden is mentioned but not in connection with Ceriantipatharia, which is also not mentioned anywhere by the German authors.

In 1956, Wells and Hill, following van Beneden, added two more criteria to group the orders Ceriantharia and Antipatharia within the subclass Ceriantipatharia: Besides the structure of the larva cerinula already described in 1897, they added that there were also similarities in the structure of the mesentery and in the mesenterial musculature.^[5]

In 1995, an analysis of the ribosomal DNA of many species within Anthozoa, found that Ceriantipatharia was "the most representative of the ancestral Anthozoa".^[6]

After an extended and important history as a major subclass of Hexacorallia, in the period 1996-2007 three studies of molecular phylogenetics ^[8][9][10] determined that Ceriantharia, instead of being a sister group of Antipatharia, is sister to, or even the basal member of Hexacorallia,^[3] and that Antipatharia, on the other hand, should be classified as an order within the class Hexacorallia, sister to the orders Scleractinia (stony corals) and Corallimorpharia (mushroom anemones).^[10][11]

In modern taxonomies and phylogenies, Ceriantipatharia became deprecated and its rank changed to order although it has had a significant bibliography and history of molecular phylogenetic studies.^[1][11]