The Pacific white skate (''Bathyraja spinosissima'') is a species of

skate Skate or Skates may refer to: Fish *Skate (fish), several genera of fish belonging to the family Rajidae * Pygmy skates, several genera of fish belonging to the family Gurgesiellidae * Smooth skates or leg skates, several genera of fish belongin ...

in the family

Arhynchobatidae Arhynchobatidae is a family of skates and is commonly known as the softnose skates. It belongs to the order Rajiformes in the superorder Batoidea of rays. At least 104 species have been described, in 13 genera. Softnose skates have at times been ...

. It is one of the deepest-living of all skates, occurring at a depth of 800 to 2,938 m on the continental slope. It is native to the southeast Pacific Ocean from the Galapagos Islands to off Waldport, Oregon; an egg case and

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

has been collected from the

Farallon Islands The Farallon Islands, or Farallones (from the Spanish ''farallón'' meaning "pillar" or "sea cliff"), are a group of islands and sea stacks in the Gulf of the Farallones, off the coast of San Francisco, California, United States. The island ...

off

San Francisco San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...

. Reports of it from the

Sea of Okhotsk The Sea of Okhotsk ( rus, Охо́тское мо́ре, Ohótskoye móre ; ja, オホーツク海, Ohōtsuku-kai) is a marginal sea of the western Pacific Ocean. It is located between Russia's Kamchatka Peninsula on the east, the Kuril Islands ...

may represent a different species. Its species name, ''spinosissima'', comes from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''spinosus'' meaning "thorny", referring to its covering of

dermal denticle A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as we ...

s. The flattened

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

disc of the Pacific white skate is slightly wider than long, with broadly rounded tips. The disc is covered with numerous small denticles above and below, giving it a

shagreen Shagreen is a type of rawhide consisting of rough untanned skin, historically from a horse's or onager's back, or from shark or ray. Etymology The word derives from the French ''chagrin'' and is related to Italian ''zigrino'' and Venetian '' ...

-like texture. Adult males possess alar spines (on the dorsal surface of the pectoral fins near the tips). The tail is slightly longer than the disc, bearing a single median row of 23-29 thorns and two similar-sized

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

s near the end without an interdorsal thorn. The caudal fin is long and tapering, with a filamentous fold on its upper surface. Its

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

number 34 in the upper jaw and 23 in the lower. This species is a uniform pale to salty gray above and below, with dusky outer disc margins. The Pacific white skate feeds on

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

es. Like other skates they are

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...

; the egg cases are olive green in color and longitudinally striated, with horn-like projections on the shell. The size at birth is about 25 cm; the maximum known size is 1.5 m. They are of no commercial interest but are occasionally taken as by-catch.

References

Pacific white skate Fish of the Western United States Western North American coastal fauna Fish of Mexican Pacific coast Western Central American coastal fauna Galápagos Islands coastal fauna Fauna of California Taxa named by William Beebe Taxa named by John Tee-Van Pacific white skate {{Rajiformes-stub