No information was found on communication in Dactyloscopidae. Because their eyes are placed on top of their heads, often on stalks, so as to remain uncovered by sand, it is logical to infer that they perceive their surroundings visually.
Perception Channels: visual ; tactile ; chemical
There is no known conservation threat to any members of Dactyloscopidae.
No information was found on development in Dactyloscopidae.
Dactyloscopids derive their common name, sand stargazers, from their eyes, which protrude from the tops of their heads, sometimes on stalks. Sand stargazers usually remain burrowed into the sand with only the eyes, along with the snout and sometimes the top of the head, uncovered. Members of this family occupy shallow warm waters and are carnivorous. They are small, cryptic fishes and little is known about their behavior or reproductive habits. There are nine genera in the family and about 41 species.
No specific information was found concerning any negative impacts to humans.
No information was found on human importance of Dactyloscopidae.
Sand stargazers occupy a specific habitat, that is, sandy bottoms of shallow warm waters, and in that setting impact the tiny fishes and invertebrates that serve as their prey.
Sand stargazers are carnivorous, lying in wait under the sand to attack small fishes and invertebrates.
Primary Diet: carnivore (Piscivore , Eats non-insect arthropods)
Dactyloscopids, or sand stargazers, are found in tropical and warm temperate waters of the western hemisphere. The Atlantic Ocean (from the United States to Brazil) contains 17 species, and the Pacific Ocean (from the Gulf of California to Chile) contains 24.
Biogeographic Regions: nearctic (Native ); neotropical (Native ); atlantic ocean (Native ); pacific ocean (Native )
Dactyloscopids live buried in the sand with only the eyes, along with the snout and sometimes the top of the head, uncovered. They usually occupy shallow warm water at depths between two and 15 m, but one species, Gillellus healae, has been found between five and 137 m. Some groups inhabit bare, open beaches in or behind the surge zone, but others are found exclusively in patches of sand that are near rocks, coral structures, or marl bottoms. A few species can be found in estuaries, and at least one enters fresh water.
Habitat Regions: temperate ; tropical ; saltwater or marine
Aquatic Biomes: benthic ; coastal
Other Habitat Features: estuarine ; intertidal or littoral
No information was found on lifespan of dactyloscopids.
Sand stargazers (family Dactyloscopidae) are small fishes adapted to burrowing in the sand. Their eyes are situated on the top of the head, sometimes on stalks, and their nostrils are tubular. They have upturned mouths, and fingerlike projections (fimbriae) line the mouth and gill covers, keeping sand out of the gills and mouth. These fish maintain water flow through the gills with a branchiostegal pump. Sand stargazers are covered with cycloid scales. The dorsal fin, which contains 7-23 spines and 12-36 soft rays, may be divided or continuous. The pelvic fins have three thickened rays with tips that are free from the fin membrane. The largest dactyloscopids reach 17 cm, but most are less than six cm. They are colored to blend in with their sandy environment: most are whitish or drab brown, and many have red-tinged or dark mottling along the back and head. (Click here to see a fish diagram)
Other Physical Features: ectothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
Sand stargazers conceal themselves from predators by hiding under the sand. They are cryptically colored, so any exposed parts blend in well with the sand.
Anti-predator Adaptations: cryptic
No information was found on mating systems in Dactyloscopidae.
While no information was found on reproduction in Dactyloscopidae, blennies (which are in the same suborder Blennioidei) in general tend to lay relatively large eggs that adhere to a surface. In the case of sand stargazers, eggs may adhere to each other, as males carry them in two clumps under the pectoral fins.
Key Reproductive Features: sexual ; fertilization (External ); oviparous
Sand stargazers display a unique trait among fishes in that males guard eggs by carrying them in two balls, one in the “armpit” (axilla) of each pectoral fin.
Parental Investment: male parental care
Sand stargazers are blennioids; perciform marine fish of the family Dactyloscopidae. Found in temperate to tropical waters of North and South America; some may also inhabit brackish 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 invertebrates and fish make up the bulk of the sand stargazer's diet.
The family name Dactyloscopidae derives from the Greek words daktylos meaning "finger" (a reference to the divided mouth and operculum fringes) and skopein meaning "to watch".
Sand stargazers are blennioids; perciform marine fish of the family Dactyloscopidae. Found in temperate to tropical waters of North and South America; some may also inhabit brackish 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 invertebrates and fish make up the bulk of the sand stargazer's diet.
The family name Dactyloscopidae derives from the Greek words daktylos meaning "finger" (a reference to the divided mouth and operculum fringes) and skopein meaning "to watch".
