Graveldiver
Encyclopedia
The Graveldivers are perciform fish in the genus Scytalina, and the only species in the family Scytalinidae. Graveldivers are small, with a snake-like head (hence the generic name). The body is compact, and lacks pelvic fins, with very small pectoral fins. Their range
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...

 encompasses the coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...

al area from the Bering Sea
Bering Sea
The Bering Sea is a marginal sea of the Pacific Ocean. It comprises a deep water basin, which then rises through a narrow slope into the shallower water above the continental shelves....

 to central California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

.

Taxonomy and naming

The generic name Scytalina is of a Greek origin, from the diminutive of skytale, meaning "viper
Viperidae
The Viperidae are a family of venomous snakes found all over the world, except in Antarctica, Australia, Ireland, Madagascar, Hawaii, various other isolated islands, and above the Arctic Circle. All have relatively long, hinged fangs that permit deep penetration and injection of venom. Four...

". This refers to the snake-like head. The specific name cerdale means "wary one" or "the fox", in allusion to its agility and quick movement when disturbed. Jordan and Gilbert suggested an alternative generic name Scytaliscus due to the similarity between Scytalina and the unrelated genus Scytalinus. This name is unnecessary and is not in wide use.

Description

Graveldivers are small fish, reaching lengths of only 15 centimetres (5.9 in), but usually not exceeding 10 centimetres (3.9 in). They are long and compressed, resembling blennies. The head is snake-like, earning it the generic name Scytalina. The dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

s and anal fins have no soft rays, and are supported only by thin spines. Each has 41–51 spines, originating deep in the skin. They are at opposite sides of the body. The dorsal and anal fins converge at the rounded caudal fin. The pectoral fins are very small, with only about eight rays, and the pelvic fins and girdle are absent altogether. Gravedivers have no lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...

, scales, pyloric caeca, or swim bladder. They are pinkish-brown in colour, and may bear some purple markings. The edge of the caudal (tail) fin is reddish-orange.

Distribution and habitat

Graveldivers are marine fish found in the cold northern and eastern Pacific Ocean, from the Bering sea
Bering Sea
The Bering Sea is a marginal sea of the Pacific Ocean. It comprises a deep water basin, which then rises through a narrow slope into the shallower water above the continental shelves....

 on the Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

n coast to Diablo Cave in central California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. They are demersal fish, occurring in tidal pools and rocky bottoms. They may burrow under rocks and substrates such as sand, gravel, and broken shells, hence their name. They may burrow to depths of 25 feet (7.6 m) or more. Graveldivers generally inhabit shallow intertidal and subtidal areas.
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