Siganus randalli
A venomous rabbitfish found in Western Pacific coral reefs.
Siganus randalli, also called the variegated spinefoot or Randall's rabbitfish, is a marine ray-finned fish from the family Siganidae. Its range is the Western Pacific Ocean.
The species was first described in 1990 by ichthyologist David J. Woodland. The type specimen came from a coral reef flat off Paruru Plantation in Marau Lagoon on Guadalcanal Island, Solomon Islands. The specific name honors American ichthyologist John E. Randall of the Bishop Museum in Honolulu, who alerted Woodland to the fish and assisted with his revision of the genus *Siganus*.
The body is deep and laterally compressed, with a depth that fits into the standard length 2 to 2.2 times. The head’s dorsal profile is indented above the eye, and the snout is slightly concave. The rear edge of the front nostril has a peak. A recumbent spine lies embedded in the nape, in front of the dorsal fin. Like all rabbitfishes, the dorsal fin has 13 spines and 10 soft rays; the anal fin has 7 spines and 9 soft rays. These spines contain venom glands. The caudal fin is emarginate. Maximum total length reaches 33.5 cm (13.2 in), though 25 cm (9.8 in) is more typical. Overall color is bronze, with pale blue spots on the head and front of the body. On the rear part, these spots become serpentine lines, separated by a line running from the base of the last dorsal spine to the base of the first anal spine. The smallest spots sit on the nape, growing larger on the cheek and again on the mid flank, with gaps between spots slightly shorter than their diameters. The spiny part of the dorsal fin is bronze; the soft part is bronze at the base and bluish toward the margin. The anal fin is bronze, with bluish tips on its soft rays. The caudal fin is blue with serpentine bronze markings that break into spots and short lines on its outer half. Pectoral fins are hyaline with blue rays; pelvic fins are bronze.
This species occurs in the West Pacific around Papua New Guinea, the Solomon Islands, and north to Pohnpei, Kosrae, and Guam in the Marianas. It lives at depths from 1 to 15 m (3 ft 3 in to 49 ft 3 in). Adults inhabit coral reefs with sand and coral rubble; juveniles are found in mangroves.
The fish forms small schools of 10 to 20 individuals over compacted pavement areas, feeding on benthic algae. Juvenile schools gather in mangroves.
Quick Facts
- Taxon
- Siganus randalli
Facts from the source article.
Lore & Background
Siganus randalli was first formally described in 1990 by ichthyologist David J. Woodland, with the type locality given as a coral reef flat off Paruru Plantation in the Marau Lagoon on Guadalcanal Island in the Solomon Islands. The specific name honors American ichthyologist John E. Randall of the Bishop Museum in Honolulu, who brought the species to Woodland's attention and assisted with his revision of the genus Siganus.
The species has a laterally compressed, deep body with a depth that fits into its standard length between 2 and 2.2 times. Its head has a dorsal profile indented above the eye, and the snout is slightly concave. The front nostril has a peak on its rear edge, and there is a recumbent spine embedded in the nape in front of the dorsal fin. The dorsal fin has 13 spines and 10 soft rays, while the anal fin has 7 spines and 9 soft rays; all fin spines hold venom glands. The caudal fin is emarginate. Overall color is bronze, with pale blue spots on the head and front of the body, replaced by serpentine lines on the rear part. The spiny part of the dorsal fin is bronze, the soft part bronze at the base and bluish toward the margin. The anal fin is bronze with bluish tips, and the caudal fin is blue with bronze markings.
Adults occur in coral reefs with sand and coral rubble, while juveniles inhabit mangroves. The species lives in small schools of 10–20 individuals and feeds on benthic algae. Its venom is similar to that of stonefishes, based on a study of a congener.
Reader's Guide
Siganus randalli is significant as a species described relatively recently, in 1990, and named after the prominent ichthyologist John E. Randall. Its venomous spines, typical of rabbitfishes, produce venom similar to that of stonefishes, highlighting a potential hazard for handlers. The species is found in the Western Pacific, including Papua New Guinea, Solomon Islands, Pohnpei, Kosrae, and Guam. It is landed in small amounts in the Philippines, though this is unconfirmed as the Philippines are outside its known range. Fijian tuna fisheries use it as bait, caught with spearguns. In Guam, research is underway to assess its potential for aquaculture. The species' habitat preferences—adults on coral reefs with sand and rubble, juveniles in mangroves—and its schooling behavior (10–20 individuals) contribute to its ecological role as a benthic algae feeder. Its maximum recorded length of 33.5 cm and typical length of 25 cm make it a moderate-sized rabbitfish. The article notes uncertainty regarding its presence in Philippine fisheries, which should be preserved.
Did You Know?
- Its fin spines contain venom glands, and the venom is similar to that of stonefishes.
- Juveniles inhabit mangroves, while adults are found on coral reefs with sand and coral rubble.
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