Giant Stargazer, Dactylagnus mundus
The Giant Stargazer, Dactylagnus mundus, whose common Spanish name is miraestrellas gigante, is a member of the Sand Stargazer or Dactyloscopidae Family, known collectively as miraestrellas in Mexico. Globally, there are only three species in the genus Dactylagnus, two of which are found in Mexican waters, both in the Pacific.
The Giant Stargazers have compressed bodies that taper from head to tail. Their upper body is brownish tan with darker brown flecks and their ventral area is white. Their abdomen and the sides of their head are silvery with four or five indistinct bars between their eyes and dorsal fins. Juveniles have 12 to 14 bars on their upper back and a series of blotches on their sides just above the midline. Their head is large and deep with a bluntly rounded snout, an upturned mouth, eyes that point skyward (after which they are named), and lips with numerous skin flaps. Their eyes are not stalked. Their anal fin has two spines and 35 to 41 rays; their dorsal fin is continuous, originates behind the anal fin, and has 8 to 12 spines and 28 to 34 rays; and their pectoral fins have a long base with 14 to 16 rays. Their lateral line is continuous. They are covered with small scales.
The Giant Stargazers are a solitary benthic coastal species normally found submerged in substrate such as beaches, sand bottoms, and soft bottom habitats in mangroves and estuaries at depths up to 50 feet. They are ambush predators that lie in wait with only their eyes exposed and consume small invertebrates and fish. They reach a maximum length of 16.5 cm (6.5 inches). They are poorly studied and little is known about their behavioral patterns.
In Mexican waters the Giant Stargazers are found in all waters of the Pacific with the exception that they are absent from Guerrero Negro northward along the central and northwest coasts of Baja.
The Giant Stargazer is most likely confused with the Panamic Stargazer, Dactylagnus parvus (saddles on back; 29 to 34 anal fin rays; dorsal fin origin before anal fin origin).
The Giant Stargazers are small and seldom seen by humans. They are of limited interest to most and currently classified as of Least Concern from a conservation perspective. They are prone to habitat loss, including mangroves, due to coastal development.
Giant Stargazer, Dactylagnus mundus. Fish caught in the surf zone via cast net, Puerto Los Cabos, Baja California Sur, March 2006. Length: 13.0 cm (5.1 inches). Identification confirmed by Dr. Ross Robertson, Smithsonian Tropical Research Institute, Panama.