The deepwater ray (''Rajella bathyphila''), also called the deepwater skate or abyssal skate, 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
Rajidae.
Distribution
The deepwater ray is
bathydemersal
Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They occ ...
; it has been recorded at , mostly below . It has been found in seas worldwide, concentrated in the
North Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and ...
, living on
continental slope
A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...
s and
abyssal plains
An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between and . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface. T ...
.
Description
Like all rays, the deepwater ray has a flattened body with broad, wing-like
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 ...
s. The dorsal surface of adults is white. The outer edges of pectoral and
pelvic fins
Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods.
Structure and function Structure
In actinopterygians, the pelvic fin consists of two en ...
shade to darker.
The upper surface is
spinulose, but there are bare patches in the centre of the pectoral fins and on sides of body in adult males.
Its maximum length is .
Behaviour
Juveniles feed on small benthic
invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
s, while larger deepwater rays feed on larger invertebrates and fish. It is parasitised by ''
Echeneibothrium bathyphilum'', a
cestode
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of man ...
tapeworm of the order
Rhinebothriidea.
Life cycle
The deepwater ray is
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
eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
have horn-like projections on the shell. Paired eggs are laid, with
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 ...
s feed solely on
yolk
Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example bec ...
.
See also
*
References
External links
*
{{Authority control
bathyphila
Fish of the Atlantic Ocean
deepwater ray
Taxa named by Ernest William Lyons Holt
Taxa named by Lucius Widdrington Byrne