Thornback guitarfish
The Thornback guitarfish is a unique species of cartilaginous fish, sharing characteristics with both sharks and rays. Named for the distinctive ridge of thorns that runs down its back, this species can be found in the warm, shallow waters off the coast of California. The Thornback guitarfish typically inhabits sandy and muddy bottoms at depths of up to 150 feet and can grow to a maximum length of around three feet. Its diet consists mainly of crabs, shrimp, snails, clams, and other bottom-dwelling organisms, making it a carnivorous predator in its ecosystem.
Mating occurs at the end of summer, with females laying between one and 15 eggs in the sand, which hatch after a year without parental care. While they have a lifespan of about 15 years, Thornback guitarfish face predation from various larger marine animals. Notably, this species is not currently classified as threatened, reflecting a stable population within its natural habitat. The Thornback guitarfish's intriguing anatomy and behavioral patterns make it a fascinating subject for those interested in marine biology and ocean life.
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Thornback guitarfish
This species of guitarfish, one of the around 50 species worldwide and one of a handful around North America, looks like a mix between a shark and a skate or ray. The first part of its name comes from the ridge of thorns down the middle of its back from nose to dorsal fin. The other part of its name comes from its body shape, which is similar to a guitar.
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Torpediniformes
Family: Platyrhinidae
Genus: Platyrhinoidis
Species: Triseriata
Warm, shallow waters along the coast of California are home to the odd-looking thornback guitarfish. The guitarfish is another of the world's cartilaginous fish, or those fish which have skeletons of cartilage instead of bones. People's ears and noses contain cartilage. The guitarfish lives mainly in depths of up to 25 fathoms, or 150 feet (45 meters), near the sandy and muddy bottom. Its long, thick tail with two dorsal (back) fins looks like that of a shark, while the flattened, disk-like head looks like that of a skate or ray. White skin covers its underside, and its top side is brown. When it is younger, the thornback has at least one row of spines, or thorns, running down the middle of its back. When it becomes an adult, it may have up to three rows of spines. The thornback may grow to be up to three feet (90 centimeters) long.
As it swims along the bottom, the thornback catches crabs, shrimp, snails and clams, and bottom-dwelling worms. Their carnivorous, or meat-eating, diet also consists of fish.
Mating season for thornback guitarfish takes place at the end of summer, usually in August. Female thornbacks deposit between one and 15 eggs in the sand. The eggs hatch after a gestation period of one year. They receive no care from either parent. Thornback guitarfish can reproduce when they reach a certain size.
Small sharks, large fish, and elephant seals may prey on the thornback guitarfish. They thornback guitarfish has a life span of 15 years. They are not a threatened species.
Bibliography
“California Thornback - Online Learning Center.” Aquarium of the Pacific, 2024, www.aquariumofpacific.org/onlinelearningcenter/species/california‗thornback. Accessed 10 May 2024.
Smithsonian Tropical Research Institute. “Shorefishes - The Fishes.” Shorefishes - The Fishes - Species, 2023, biogeodb.stri.si.edu/sftep/en/thefishes/species/184. Accessed 10 May 2024.