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sand devil
The sand devil or Atlantic angel shark (''Squatina dumeril'') is a species of angel shark, family Squatinidae, native to the northwestern Atlantic Ocean. It occurs off the eastern United States, in the northern Gulf of Mexico, and possibly in parts of the Caribbean Sea. This bottom-dwelling shark is found in shallow inshore waters in summer and fall, and deep offshore waters in winter and spring. The sand devil's flattened body and enlarged pectoral and pelvic fins give it a ray-like appearance. There is a band of enlarged thorns running along the middle of its back. It is gray or brown in color, with scattered small dark spots. This species reaches in length.
The diet of the sand devil consists mainly of small teleost fishes and squid, which are captured via ambush attack. This species is viviparous, with the unborn young nourished by their yolk sacs. Females have a multi-year reproductive cycle and give birth to 4–25 pups in spring or early summer, following a 12-month gestation period. The sand devil is not aggressive, but may attempt to bite if harassed or captured. Though not valued economically, it is caught incidentally by commercial bottom trawl fisheries. The International Union for Conservation of Nature (IUCN) presently lacks sufficient information to assess the conservation status of this species.
==Taxonomy and phylogeny==
French naturalist Charles Alexandre Lesueur described the sand devil in an 1818 volume of ''Journal of the Academy of Natural Sciences of Philadelphia''. Previously, it had been regarded as the same species as the European ''Squatina squatina''. Lesueur based his account on a long adult male caught off the eastern United States, and named the species in honor of André Marie Constant Duméril.〔
Phylogenetic analysis, based on mitochondrial DNA, has concluded that the sand devil and the Pacific angel shark (''S. californica'') are sister species. The two of them in turn form a clade with other angel sharks found in the Americas. Molecular clock estimation has timed the divergence of ''S. dumeril'' and ''S. californica'' at ''c.'' 6.1 Ma, around the time that the Isthmus of Panama formed. It is likely that the rise of the Isthmus split the ancestral angel shark population, leading to their becoming separate species.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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