''Patiria miniata'', the bat star, sea bat, webbed star, or broad-disk star, is a species of

sea star Starfish or sea stars are Star polygon, star-shaped echinoderms belonging to the class (biology), class Asteroidea (). Common usage frequently finds these names being also applied to brittle star, ophiuroids, which are correctly referred to ...

(also called a starfish) in the family

Asterinidae The Asterinidae are a large family of sea stars in the order Valvatida. Description and characteristics These are generally small sea stars, flattened dorsally and bearing very short arms, often giving a pentagonal shape in the body ;example: ...

. It typically has five arms, with the center disk of the animal being much wider than the stubby arms are in length. Although the bat star usually has five arms, it sometimes has as many as nine. Bat stars occur in many colors, including green, purple, red, orange, yellow and brown, either mottled or solid. The bat star gets its name from the webbing between its arms, which is said to resemble a

bat Bats are flying mammals of the order Chiroptera (). With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most birds, flying with their very long spread-out ...

's wings. The bat star is usually found in the

intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

to a depth of . Its range extends from Sitka, Alaska to

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

in the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

. It is most abundant along the Central Coast of California.

Classification

The genus of this species has transitioned back and forth between '' Asterina'' and ''Patiria'' since its inclusion in Fisher's 1911 North Pacific Asteroidea monograph. However, recent revisions based on molecular systematics have constrained ''Asterina'' and identified ''Patiria'' as a

complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

of three closely related species in the Pacific, including ''P. miniata'', '' P. pectinifera'' in Asia and '' P. chilensis'' in South America.

Anatomy

Bat stars can be many different types of colors. The bat star breathes through

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

-like structures on its back that perform as respirators. It lacks the pincers or

pedicellariae A pedicellaria (: pedicellariae) is a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea). ...

that most starfish use to clean the skin surface of debris, but its small, moving hairs or

cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...

may create enough of a water current to keep the surface of its skin clean. It has visual sensors at the end of each ray that can detect light and note prey. To eat its prey, it covers the prey with its stomach and oozes

digestive juice Gastric acid or stomach acid is the acidic component – hydrochloric acid – of gastric juice, produced by parietal cells in the gastric glands of the stomach lining. In humans, the pH is between one and three, much lower than most other a ...

s over it; this liquefies the food, enabling the bat star to ingest it. It is

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

, eating both plants and animals alive or dead.

Reproduction

3D projection of a Patiria miniata bipinnaria

The bat stars reproduce through

spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...

. The male casts sperm and the female drops eggs; each has pores at the base of the rays for this purpose. The sperm and egg unite at sea and are carried away by ocean currents.

Behavior

Bat stars may gently "fight" with each other if they meet. Fighting behavior consists of pushing and laying an arm over the other. Bat stars are important as

detritivore Detritivores (also known as detrivores, detritophages, detritus feeders or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, ...

s and

scavenger Scavengers are animals that consume Corpse decomposition, dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a he ...

s, collecting

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

and dead animals from the ocean floor. Their primary food source is algae, including

seaweed Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of ''Rhodophyta'' (red), '' Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...

and drifting algae, but they may also steal algae from

sea urchins Sea urchins or urchins () are echinoderms in the class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body covered by a spiny p ...

Bryozoans Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic animal, aquatic invertebrate animals, nearly all living in sedentary Colony (biology), colonies. Typically about long, they have a spe ...

are an incidental food source for the bat stars, and the bat stars have been observed to favour '' Tubulipora'' species in southern California. Juvenile bat stars live under rocks and boulders, while adults live out in the open. The largest adults can grow up to in diameter.

References

{{Taxonbar, from1=Q3468311, from2=Q2406146 Asterinidae Echinoderms of the Pacific Ocean Starfish described in 1835 Taxa named by Johann Friedrich von Brandt