Smooth Stargazer, Kathetostoma averruncus
The Smooth Stargazer, Kathetostoma averruncus, whose common Spanish name is miracielo buldog, is a member of the Stargazer or Uranoscopidae Family, known collectively as miracielos in Mexico. Globally, there are only seven species in the genus Kathetostoma, three of which are found in Mexican waters, two in the Atlantic and this species in the Pacific.
The Smooth Stargazers have short thick bodies that taper toward the rear. They are dark green, brown, or gray dorsally and transition to light brown ventrally. They have white spots on their head and larger white spots and blotches on their body. Their caudal, dorsal, and pectoral fins have white margins. The tips of their opercular spines are yellow. They have a large square head with large eyes and a large vertical mouth. A key to identification is a pair of large venomous spines at the upper edge of their operculum (clearly visible in photos below); they also have three non-venomous spines on the lower edge of their gill covers. Their anal and dorsal fins have no spines and they lack scales. Their pectoral fins are large.
The Smooth Stargazers are a solitary benthic coastal species normally found submerged in substrate (beaches, sand bottoms, and soft bottom habitats in mangroves and estuaries) at depths between 40 and 2,000 feet. They reach a maximum length of 32 cm (13 inches). They are ambush predators that lie in wait with only their eyes exposed; they consume small invertebrates and small fish. Juveniles are pelagic and eaten by large predatory fish such as tuna. They are poorly studied and little is known about their behavioral patterns.
The Smooth Stargazers are found in all Mexican waters of the Pacific with the exception that they are absent from the northern two-thirds of the Sea of Cortez.
The Smooth Stargazer can be confused with the Pacific Stargazer, Astroscopus zephyreus (larger; small eyes; no large white spots).
The Smooth Stargazers are mid-sized fish but seldom seen by humans and of limited interest to most. They are used on a limited basis by the aquarium trade. A word of caution! The Smooth Stargazers have a pair of large poisonous spines and therefore should be handled with extreme caution. From a conservation perspective they are currently considered of Least Concern. They are prone to habitat loss from coastal development.