Manta rays

Manta rays are large eagle rays belonging to the genus Manta. The larger species, M. birostris, reaches 7 m (23 ft 0 in) in width while the smaller, M. alfredi, reaches 5.5 m (18 ft 1 in). Both have triangular pectoral fins, horn-shaped cephalic fins and large, forward-facing mouths. They are classified among the Elasmobranchii (sharks and rays) and are placed in the eagle ray family, Myliobatidae.

Mantas can be found in temperate, subtropical and tropical waters. They are filter feeders and eat large quantities of zooplankton, which they swallow with their open mouths as they swim. Gestation lasts over a year, producing live pups. Mantas may visit cleaning stations for the removal of parasites. Like whales, they breach, for unknown reasons.

Both species are listed as vulnerable by the International Union for Conservation of Nature. Anthropogenic threats include pollution, entanglement in fishing nets, and direct harvesting for their gill rakers for use in Chinese medicine. Their slow reproductive rate exacerbates these threats. They are protected in international waters by the Convention on Migratory Species of Wild Animals, but are more vulnerable closer to shore. Areas where mantas congregate are popular with tourists. Only a few aquariums are large enough to house them. In general, these large fish are seldom seen and difficult to study.

Manta rays are members of Chondrichthyes, fish with tough cartilage rather than bone in their skeletons.Mantas are among the Elasmobranchii (sharks and rays), in the superorder Batoidea (rays and skates)and the order Myliobatiformes (stingrays and relatives). The genus Manta is part of the eagle ray family Myliobatidae, where it is grouped in the subfamily Mobulinae along with the devil rays. Mantas evolved from bottom-dwelling stingrays, eventually developing more wing-like pectoral fins.M. birostris still has a vestigial remnant of a sting barb in the form of a caudal spine.The mouths of most rays lie on the underside of the head, while in mantas they are right at the front.Manta rays and devil rays are the only ray species that have evolved into filter feeders.

The scientific naming of mantas has had a convoluted history, during which several names were used for both the genus (Ceratoptera, Brachioptilon Daemomanta and Diabolicthys) and species (such as vampyrus, americana, johnii and hamiltoni). All were eventually treated as synonyms of the single species Manta birostris. The genus name Manta was first published in 1829 by Bancroft. The specific name birostris is ascribed to Walbaum (1792) by some authorities and to Dondorff (1798) by others.The name alfredi was first used by Australian zoologist Gerard Krefft, who named the manta after Prince Alfred.

Authorities were still not in agreement and some argued that the black color morph was a different species from the mostly white morph. This proposal was discounted by a 2001 study of the mitochondrial DNA of both.:49 A 2009 study analyzed the differences in morphology, including color, meristic variation, spine, dermal denticles (tooth-like scales) and teeth of different populations. Two distinct species emerged: the smaller M. alfredi found in the Indo-Pacific and tropical east Atlantic, and the larger M. birostris found throughout tropical, subtropical and warm temperate oceans.The former is more coastal while the latter is more ocean-going and migratory.A third possible species, preliminarily called Manta sp. cf. birostris, reaches at least 6 m (20 ft) in width, and inhabits the tropical west Atlantic, including the Caribbean. It and M. birostris occur in sympatry. A 2010 study on mantas around Japan confirmed the morphological and genetic differences between M. birostris and M. alfredi.