Sea bat
The sea bat, also known as the webbed star, broad-disk star, or bat star, is a unique species of starfish belonging to the genus Patiria. This marine creature is identified by its distinctive winged appearance, where the arms are connected by hard tissue rather than being separate, a feature that sets it apart from most starfish. Inhabiting the rocky shores of North and Central America, particularly along the west coast from Alaska to Mexico, the sea bat thrives in tidal pools but can also be found at depths of up to 950 feet (290 meters).
Typically measuring between 5 to 8 inches (12 to 20 centimeters) in diameter, sea bats display a variety of colors including red, yellow, orange, brown, green, and purple. They are omnivorous, feeding on a diet of plants and animals such as sea urchins, seagrass, sponges, and algae. Unique among starfish, sea bats utilize external digestion by spraying digestive fluids onto algae to soften it before consumption. Reproduction occurs in the spring through a process called spawning, where eggs and sperm are released into the water for external fertilization. The sea bat has a lifespan ranging from 5 to 35 years, contributing to its ecological role along the coastal environments it inhabits.
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Sea bat
The sea bat is named for its winged appearance. Instead of having separate arms like most starfish, the arms of the sea bat are covered and connected with hard tissue. It is also called the webbed star, broad-disk star, and bat star.
Kingdom: Animalia
Phylum: Echinodermata
Class: Asteroidea
Order: Valvatida
Family: Asterinidae
Genus: Patiria
Species: Miniata
The sea bat inhabits the rocky shores of North and Central America along the west coast from Alaska to Mexico. It is most common in the tidal pools along these rocky beaches but may live at depths of up to 950 feet (290 meters). The largest populations occur off the coast of central California.
The sea bat is a small starfish that grows to 5 to 8 inches (12 to 20 centimeters) in diameter. A diameter is the measurement across a circular object. The sea bat is measured from the tip of one of its five arms to the tip of the arm directly across from it. Since the sea bat is radially symmetrical, the distance between the tips of any opposite two of its five arms should be the same. To be radially symmetrical means to be constructed around a central axis, or point, and have all appendages extend equally in a circle from that point. All members of the phylum Echinodermata are radially symmetrical.
The five-armed body of the plant-eating starfish may be red, yellow, orange, brown, green, or purple. Unlike most starfish, which have separated arms, the arms of sea bats are connected. Polychaete worms (Ophiodromus pugettensis) live between the bat star's arms, eating bacteria. The connecting material is part of the hard exoskeleton, or external skeleton, of the sea bat. This form causes them to appear as though it is blanketed with an extra outer layer. On the bottom of the sea bat are five slits that run along the centers of each of the five arms from the central axis of the sea bat to the outer points of its arms. Within these slits are tiny, hollow, tube-like appendages, or tube feet. The sea bat uses its tube feet mostly in feeding but also extends them from the slits to stick to smooth surfaces.
Sea bats are omnivorous, feeding on plants and animals like sea urchins, seagrass, sponges, and algae. Its feeding methods are similar to other starfish. The sea bat inverts, or turns out, its stomach through its mouth opening. Instead of spraying its stomach fluids into the opened shells of mollusks like other starfish, the sea bat sprays its digestive fluids on algae. This softens the algae and enables the sea bat to suck the softened algae into its body. When a sea bat is kept in an aquarium, it helps to clean its tank by feeding on the algae that collect on the glass walls of the aquarium.
The mating season for the sea bat is in the spring when the water is warm. The male and female release their eggs and sperm into the water. The eggs are fertilized by the sperm in the water. This process of external fertilization is known as spawning. After being fertilized, the eggs float out to sea along the water's surface. Eventually, they develop stronger limbs and sink to the seabed. From there, they make their way to the beach and mature into adults.
The life span of the sea bat is 5 to 35 years.
Bibliography
"Bat Star." Georgia Aquarium, www.georgiaaquarium.org/animal/bat-star. Accessed 1 May 2024.
"Bat Star." Monterey Bay Aquarium, www.montereybayaquarium.org/animals/animals-a-to-z/bat-star. Accessed 1 May 2024.
Ervin, Jennifer. "Patiria Miniata." Animal Diversity Web, animaldiversity.org/accounts/Patiria‗miniata. Accessed 1 May 2024.