''Henricia sanguinolenta'', commonly known as the northern henricia, is a species of sea star from the

North Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and ...

and North Pacific oceans. ''Henricia sanguinolenta'' is very similar to '' Henricia oculata'', also known as "bloody Henry", and the two can only be distinguished by laboratory tests. It comes in colors of red, yellow, orange, purple, and lavender.

Habitat

''Henricia sanguinolenta'' is found in the North Atlantic and North Pacific oceans. The sea star can be seen on the beach, under rocks, in

tidal pool A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. Many of these pools exist as separate bodies of water only at low tide. Many tide pool habitats are home to especially adaptable animals that ...

s when available, and on

gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is classifi ...

. Its aquatic biomes are the coastal and

benthic zone The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning " ...

s. The sea star is almost always found near sponges and coral because of the currents they create, making it easier for the sea star to filter feed. ''Henricia sanguinolenta'' is found from depths of 0 to 2414 meters.

Diet

''Henricia sanguinolenta'' is a planktivore and carnivore. The sea star filter feeds upon

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

and

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

floating in the water, and uses currents made by sponges or coral to make this process easier. ''Henricia'' feeds on plankton, sponge tissue, ascidians, and other

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s. It is eaten by

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...

Reproduction

;Sexual reproduction: ''Henricia sanguinolenta'' is a stable gonochoric. The sea star usually reproduces during February and May. The sea stars migrate to warm, shallow water during the breeding season. The sea stars mate through disk fusion. The eggs are then kept under the disk of the female starfish to incubate after

fertilization Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...

occurs. After incubation, the female deposits its eggs on the ground, secretes

mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...

onto them, and then stays on top of the eggs for three weeks while they hatch. The sea stars are

polygamous Crimes Polygamy (from Late Greek (') "state of marriage to many spouses") is the practice of marriage, marrying multiple spouses. When a man is married to more than one wife at the same time, sociologists call this polygyny. When a woman is ...

. ''Henricia sanguinolenta'' has a diploid chromosome number of 36. ;Asexual reproduction: Although ''Henricia sanguinolenta'' can reproduce sexually, it can also

reproduce asexually Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the fu ...

. It reproduces asexually through the process of regeneration. The sea star can go through regeneration if the disc is split in half, or even if a ray is cut off. The regeneration process takes weeks to months to complete.

Anatomy

;Rays: ''Henricia sanguinolenta'' is an invertebrate. It has slender five rays that taper evenly to tips that are connected by a central disc. The sea star grows to a

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for ...

of 5 to 12 centimeters. On the oral side, the rays are smooth and have an

ambulacral groove Ambulacral is a term typically used in the context of anatomical parts of the phylum Echinodermata or class Asteroidea and Edrioasteroidea. Echinoderms can have ambulacral parts that include ossicles, plates, spines, and suckers. For example, sea ...

that contains two tube foot rows. On the dorsal side, the rays are rough with groupings of spinelets, each one have three to six glassy points. The sides of the rays are curving and smooth. The rays contain many of the organs in the sea star. On the tips of the rays are the eyespots. These are dark

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

ed organs that sense the presence of light. The rays also contain parts of the

pyloric stomach The pylorus ( or ), or pyloric part, connects the stomach to the duodenum. The pylorus is considered as having two parts, the ''pyloric antrum'' (opening to the body of the stomach) and the ''pyloric canal'' (opening to the duodenum). The ''pylori ...

, parts of the nervous system, and most other organs. ;Tube foot rows: The tube foot rows are on the oral side of the rays. Each ray has two tube foot rows. The tube foot rows are attached to the rays by ambulacral grooves. The Tube Foot Rows use a chemical

adhesive Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advant ...

to stick to surfaces instead of

suction Suction is the colloquial term to describe the air pressure differential between areas. Removing air from a space results in a pressure differential. Suction pressure is therefore limited by external air pressure. Even a perfect vacuum cannot ...

. The tube foot rows help the sea star stick to its prey, and to bring the prey to its mouth. The tube foot rows also aid in

gas exchange Gas exchange is the physical process by which gases move passively by Diffusion#Diffusion vs. bulk flow, diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liqui ...

. the tube foot rows are sensitive to chemicals enabling the sea star to detect chemical trails left by possible food. The tube foot rows also excrete waste

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

through

diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...

. ;Nervous system: ''Henricia sanguinolenta'' has no brain, but has a

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...

. The sea star has no capacity for planning. The nervous system has two parts. They are motor system and the sensory system which are interconnected by

neurons A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. N ...

. The motor system is responsible for movement and functioning and the sensory system is responsible for controlling the sensory organs. Both of these systems run up and down the arms, and around the disc. ;Vascular tube system: ''Henricia sanguinolenta'', like all other sea stars, uses water instead of blood. ''Henricia sanguinolenta'' pumps filtered seawater in and out of its body. This seawater is transported through a vascular tube system, and delivers nutrients to the different organs and helps in gas exchange. Water enters through the madreporite, a sieve-like structure on the oral side. ;Body wall: The body wall is composed of epidermis,

dermis The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided i ...

, thin

cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...

, and a thin

coelomic A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid. The two largest human body cavities are the ventral body cavity, and ...

myoepithelial layer. ;Digestive system/stomachs: ''Henricia sanguinolenta'' has two stomachs, a small

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans ...

, and a

rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the Gastrointestinal tract, gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the s ...

leading to an

anus The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, d ...

. The two stomachs are called the cardiac stomach, and the

. The cardiac stomach is on the oral side, in the center of the disc. It is covered by a thin membrane and sphincter. When the sea star has its prey, it extends the stomach to envelope the prey. Once the prey is enveloped, it then retracts back into the disc, and transfers it to the pyloric stomach for further digestion. The pyloric stomach has two extensions into each arm called the pyloric caeca. These secrete digestive

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

s into the pyloric stomach. Then, the waste is transported through a short intestine, and rectum. The material that is left is secreted through a small anus on the oral side of the disc. ;Papulae: The

papulae Papulae (sing. papula; also occasionally papulla, papullae), also known as dermal branchiae or skin gills, are projections of the coelom of Asteroidea that serve in respiration and waste removal. Papulae are soft, covered externally with the epi ...

are small are small

gill A gill () is a respiratory organ that many 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 respiration on land provided they are ...

s on the rays and disc. Waste

is transported to the tips of the papulae using

phagocytic cell Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek ...

s, and is then excreted. ;Circulatory System: ''Henricia sanguinolenta'' has a circulatory system that forms three rings of vessels. They are called the hyponeural haemal ring, the gastric ring, and the genital ring. The heart beats six times every minute and connects all three vessels. At the base of each ray, there is a pair of

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...

Behavior

''Henricia sanguinolenta'' shows behavioral adaptations in addition to physical ones. The sea star is usually seen with sponges and coral, using the currents they make to feed upon

. ''Henricia sanguinolenta'' is also one of the only species of sea stars that broods its eggs. The female stays with the eggs while they hatch, and continues to stay with them as

larvae A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

. The larvae stay in a

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

shape created by the female's arms until they are ready to go into the ocean on their own. Until spring time, ''Henricia sanguinolenta'' lives a solitary life. ''Henricia sanguinolenta'' also doesn't react to the fluid of Asterias forbesi, which is toxic to most other sea stars.

Impact on humans

''Henricia sanguinolenta'' has no negative or positive impact on humans. The sea star is not harmful to humans or the economy, and only may slightly affect the tourist industry with its bright colors.

References

{{Taxonbar, from=Q2462631 Echinasteridae Starfish described in 1776 Taxa named by Otto Friedrich Müller