Giant Stargazer, Dactylagnus mundus
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.
Giant Stargazer, Dactylagnus mundus. Fish caught off the beach at Cabo Real, Baja California Sur, April 2020. Length: 13.5 cm (5.3 inches).
The Giant Stargazer, Dactylagnus mundus, is a member of the Sand Stargazer or Dactyloscopidae Family, and is known in Mexico as miraestrella gigante. Globally, there are three species in the genus Dactylagnus, of which two are found in Mexican waters, both in the Pacific Ocean.
The Giant Stargazer has a compressed body that tapers 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 2 spines and 35 to 41 rays; their dorsal fin has 8 to 12 spines and 28 to 34 rays and originates behind the anal fin; and, their pectoral fins have a long base with 14 to 16 rays. They are covered with small scales. Their lateral line is continuous.
The Giant Stargazer is 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 15 m (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 of 16.5 cm (6.5 inches) in length. The Giant Stargazer is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.
The Giant Stargazer is a resident of all waters of the Pacific with the exception that they are absent from Guerrero Negro, Baja California 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; 29-34 anal fin rays; dorsal fin origin before anal fin origin).
From a conservation perspective the Giant Stargazer is currently considered to be of Least Concern with stable, widely distributed populations. Long term they are prone to habitat loss, including mangroves, due to coastal development. They are small in stature and seldom seen by humans. They are of limited interest to most.