Sand stargazers are blennioids;

perciform Perciformes (), also called the Acanthopteri, is an order or superorder of ray-finned fish in the clade Percomorpha. ''Perciformes'' means "perch-like". Among the well-known members of this group are perches and darters (Percidae), and also sea ...

marine

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

of the family Dactyloscopidae. Found in temperate to tropical waters of

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and

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; some may also inhabit

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

environments. The giant sand stargazer (''Dactylagnus mundus'') is the largest at 15 cm in length; all other species are under 10 cm. These blennies are named well: sand stargazers have protruding eyes on the top of their heads, fixed in an upward gaze, and may be on stalks. Their large mouths are also upturned. The dorsal fin is long and may or may not be continuous, with seven to 23 spines; the pelvic fins are situated below the throat and possess one spine. The anal fin is equally long and flowing. The mouth is fringed, and like the upper edge of the operculum (the gill cover), this fringe is divided into finger-like structures. The body is greatly elongated, and coloration is generally drab. As their name would suggest, sand stargazers spend most of their time buried in sandy substrates waiting for unsuspecting prey; only the eyes, nose and mouth are usually visible. Their mode of respiration is also unique among the blennioids, using a branchiostegal rather than opercular pump; this is thought to be an adaptation to their largely sedentary, obscured lives. Sand stargazers generally stay within shallow (< 10 m) intertidal zones in areas protected from surges. Small

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s and fish make up the bulk of the sand stargazer's diet. The family name Dactyloscopidae derives from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

words ''daktylos'' meaning "finger" (a reference to the divided mouth and operculum fringes) and ''skopein'' meaning "to watch".

References

{{Taxonbar, from=Q2166073 Blenniiformes

See also

References