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Raja rhina

(Longnose Skate)

Common Names

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Click on the language to view common names.

Common Names in Dutch:

Langsnuitrog

Common Names in English:

Longnose Skate

Common Names in Mandarin Chinese:

長吻鰩, 長吻鰩, 长吻鳐

Common Names in Polish:

Raja Dlugonosa

Common Names in Salish:

K´ak´ew´, K'ak'ew'

Common Names in Spanish:

Raya Murcilago Moteada, Raya Narigona

Common Names in Tsimshian:

Gandah, K´andah, K'andah

Description

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Family Rajidae

Benthic rays occurring in all oceans, from Arctic to Antarctic waters and from shallow coastal shelfs to abyssal regions; rare in tropical shallow waters or near coral reefs; some species enter brackish waters. Disc quadrangular to rhomboidal . Mouth transversed to arched, with numerous teeth. Five pairs of ventral gill slits . Tail very slender, with lateral folds, usually 2 reduced dorsal fins and a reduced caudal fin. Electric organs weak, developed from caudal muscles. Skin prickly in most species, the prickles often in a row along midline of dorsal. Oviparous ; eggs in a horny capsule with four long tips . A reversal to egg-laying from live-bearing was observed in this group based on fossil records (Ref. 50449). Skates feed on other benthic organisms. Skate wings are considered good eating. The following subgenus have been elevated to the genus level: Amblyraja, Dipturus, Fenestraja, Leucoraja, Okamejei, Rajella, Rostroraja (Ref. 27314).The family Rajidae belongs to the Class Elasmobranchii (sharks and rays) and the Order Rajiformes. It contains 14 genera and 200 species. It may be found in Marine and Brackish environments and is primarily Marine. Members of this family are not used in the aquarium trade. Reproductively, most members of this family are nonguarders. The main mode of swimming of adult fish in this family is rajiform. Compared with other fish, the activity level of this family tends to be normal. Members of this family have been dated back to the Cretaceous period. Etymology of this family name : Latin, raja = ray

Physical Description

Species Raja rhina

Distinctive Features: The body of the longnose skate is flattened and not clearly defined from the pectoral fins or head . The anterior margin of the disk (body) is strongly concave . The pectoral fins are broad. The snout is stiff, long, and acutely pointed and the mouth is directed downward. The five gill slits are located ventrally and spiracles are large and behind the eyes on the dorsal surface. The small dorsal fins are closely spaced and located on the tail. The pelvic fins are deeply notched into two lobes . The caudal fin is reduced to a low ridge on the tail and the anal fin is absent.

Dentition: Dentition of the longnose skate consists of small teeth arranged in diagonal rows . Each tooth is plate-like with a very small cusp .

Denticles : There are approximately 20 sharp mid-dorsal thorns running along the tail. One to two dorsal mid-dorsal thorns are located just posterior to the eyes and there is a discontinuous row of thorns around the inner edge of the orbit.

Scales on the longnose skate are placoid in shape and very small. There are a few scales located on the snout and on the ventral surface of the anterior edge of the pectoral fins.

Color:

The dorsal surface of the longnose skate is dark brown with a dark eyespot on the base of each pectoral fin. Each eyespot has a pale center and border . There may also be a light spot located just behind the eyespot. The ventral surface is bluish, gray-black or light brown in color.

Size/Age/Growth

The maximum reported size of the longnose skate is 4.6 feet (140 cm) total length with individuals averaging 2-3 feet (.6-.9 m ) total length. Males are generally much smaller than females. Males mature at 2-2.4 feet (61-74 cm) and females at 2.3-3.3 feet (70-100 cm) total length, correlating to 6-9 years of age. The life span of this species is currently unknown, although individuals up to 13 years of age have been reported.

Habitat

The longnose skate is commonly found on the floor of the sea , occurring at depths ranging from 82-2,215 feet (25-675 m ). Found partially or completely buried on sand and silty bottoms (Ref. 27436). As a bottom dweller, it is often observed partially or entirely buried in sand and silt bottoms with its eyes protruding above the surface. The coloration of this skate is used to camouflage it with the bottom substrate. To move, the longnose skate undulates the pectoral fins in a graceful sweeping motion, appearing to fly rather than swim through the water.

Typically found in water with a depth of 0 to -5,246 meters (0 to -17,211 feet).Mean = -648.130 meters (-2,126.411 feet), Standard Deviation = 1,121.790 based on 374 observations. Ocean depth information for each observation from British Oceanographic Data Centre.

Biome: Saltwater . Bathydemersal .

Biology

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Diet

The longnose skate feeds on small fishes and invertebrates including crustaceans, worms and mollusks. Skates feed by pouncing on top of its prey , trapping it against the sea floor.

Reproduction

Skates are oviparous , or egg laying , animals. Distinct pairing with embrace.

Elasmobranchs have internal fertilization with the male inserting one clasper into the female cloaca to deliver the sperm . After fertilization, the female forms a tough, permeable egg case that surrounds the egg. After a period of several months, the female deposits the egg on the sea floor. The egg case is oblong with hook-like horns on each corner and measures about 3.9 inches (10 cm) long and 2.4 inches (6 cm) wide.

The embryo continues to develop with nourishment provided by a yolk . When the yolk is depleted a few months later, the embryo exits the egg case. Upon hatching , the young skate is similar in appearance (other than size) to an adult longnose skate.

Young may tend to follow large objects, such as their mother (Ref. 205).

Behavior

Predators:

The longnose skate falls prey to large bony fish and sharks . Adaptations for predator avoidance includes camouflage coloration as well as the ability to bury themselves in sandy or silty bottoms . Thorns on the tail and near the eyes also deter predators from making the longnose skate a potential victim. Snails and marine mammals often consume the egg cases of the longnose skate.

Parasites:

Ny fishes have Myxosporean (class Myxozoa) parasites in their tissues with the longnose skate being no exception. Sphaerospora araii n.sp. has been documented from the kidney of a longnose skate captured in the eastern Pacific Ocean in waters off Canada. The nematode Capillaria freemani sp. nov. is also a parasite reported from the longnose skate.

Taxonomy

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Unambiguous Synonyms

  1. Raia rhina Jordan & Gilbert, 1880

Notes

Name Status: Accepted Name . Synonym: Raia rhina. Latest taxonomic scrutiny: November 15, 1999.

Family : Skates .

In 1880, Jordan and Gilbert originally described the longnose skate as Raia rhina which was later changed to the currently valid name Raja rhina . The genus name Raja is derived from the Latin "raja" meaning skate and the species name rhina is derived from the Greek "rhinos" meaning nose. There are no known synonyms used to refer to this species in past scientific literature.

Common names include longnose skate (English), gandah (Tsimshian), f'ak'ew' (Salish), langsnuitrog (Dutch), raja dlugonosa (Polish), and raya narigona (Spanish). Other common names: Tsimshian: Gandah, Salish: K'ak'ew', Tsimshian: K'andah, Dutch: Langsnuitrog, Polish: Raja dlugonosa, Spanish: Raya narigona

Similar Species

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The longnose skate is similar in appearance to the California skate (R. inornata). However, the California skate can be distinguished by rounded pectoral fin tips and it is a shallow water species, only very rarely occurring in water deeper than 40 feet (12.2 m).

The deepsea skate (Bathyraja abyssicola) is also sometimes confused with the longnose skate. While the deepsea skate also has a long snout, its snout is thicker than the longnose skate's snout. The deepsea skate also lacks orbital thorns.

Another skate similar in appearance to the longnose skate is the big skate (Raja binoculata). The snout of the big skate is less pronounced and the anterior margins of the pectoral fins are less concave than the longnose skate. Coloration patterns also differ with the big skate having large dark spots on the pectoral fins that lack pale centers in contrast to the longnose skate that has spots with pale centers and borders.

Members of the genus Raja

There are approximately 96 species in this genus:

R. ackleyi (Ocellate Skate) · R. ackleyi ornata · R. actispina · R. africana (African Ray) · R. agassizii · R. aguja · R. albolinea · R. antiqua · R. arctowskii · R. asterias (Atlantic Starry Skate) · R. atriventralis · R. bahamensis (Bahama Skate) · Leucoraja leucosticta · Rajella bathyphila · R. binoculata (Big Skate) · R. brachyura (Blonde) · R. brasiliensis · R. breviraja · R. cervigoni (Finspot Ray) · R. clauata · R. clavata (Maiden Ray) · R. cortezensis (Cortez' Ray) · R. dipturus · R. dux · R. eglanteria (Clear-Nosed Brier Skate) · R. equatorialis (Ecuatorial Ray) · R. equatoriallis · Psammobatis extenta · R. falsavela intermedia · R. falsavela maggiore · R. farishi · R. fulginea · Rajella bigelowi · R. fyllae lipacantha · R. garmani caribbaea · R. garmani virginica · R. clavata · R. granulata · R. herwigi (Cape Verde Skate) · R. inornata (California Ray) · R. inornuata · R. koreana (Korean Skate) · R. lamprieri · R. lentiginosus · R. lentignosa · Rajella barnardi · Dipturus oxyrinchus · R. macrorhynchus · R. maderensis (Madeira Ray) · R. maroccana · R. microocellata (Owl Ray) · R. miraletus (Brown Ray) · R. montagui (Homelyn Ray) · R. montereyensis · R. naevis · R. ocellifera · R. brachyura · R. ornata · R. oxyrhinchus · R. oxyrynchus · R. pastinaca altavela · R. platna · Neoraja stehmanni · R. polystigma (Speckled Ray) · R. porosa fusca · R. psammobatis · R. pulchra (Mottled Skate) · R. clavata · R. purpuri · R. purpuri-ventralis · R. purpuri-ventris · Leucoraja circularis · R. radiataa · R. radula (Rough Ray) · Bathyraja maccaini · R. rhina (Longnose Skate) · R. rondeleti (Rondelet's Ray) · R. rouxi · R. scabra · R. scabrata · R. sephen uarnak · R. spincauda · R. spinosa · R. spinossismus · R. spp · R. stabuliformis · R. stellulata (Pacific Starry Skate) · R. straeleni (Biscuit Skate) · R. subgen. · R. texana (Roundel Skate) · Malapterurus electricus (Skates) · Dasyatis guttata · R. umbra · R. undulata (Painted Ray) · R. velezi (Rasptail Ray) · R. whitleyi (Great Skate)

Bibliography

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More Info

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal March 04, 2008:

Identifiers

Footnotes

Last Revised: 2008-09-06