| Stenorhynchus seticornis | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Family: | Inachidae |
| Genus: | Stenorhynchus |
| Species: | S. seticornis |
| Binomial name | |
| Stenorhynchus seticornis (Herbst, 1788) | |
Stenorhynchus seticornis, the yellowline arrow crab or simply arrow crab, is a species of marine crab.
Stenorhynchus seticornis was first described by Johann Friedrich Wilhelm Herbst in 1788, under the name Cancer seticornis. It was also described as "Cancer sagittarius" by Johan Christian Fabricius in 1793, a name which is now a junior synonym of S. seticornis. [1] Pierre André Latreille erected the genus Stenorhynchus (originally mis-spelt Stenorynchus) in 1818, [1] and S. seticornis was confirmed as the type species by the International Commission on Zoological Nomenclature in 1966. [2]
The body of S. seticornis is triangular, and the rostrum is drawn out into a long point with serrate edges. [3] The legs are also long and thin, up to 10 cm (3.9 in) across, [4] and the animal's carapace may be up to 6 cm (2.4 in) long. [5] Colouration is variable in this species; the body may be golden, yellow or cream, marked with brown, black or iridescent-blue lines; the legs are reddish or yellow, and the claws are blue or violet. [5] This species presents as diagnostic features: triangular body with long pointed snout (rostrum), carapace decorated with fine dark lines and claws often have violet tips. S. seticornis is most commonly associated with anemones, in groups ranging from one to six individuals in south-eastern Brazil. [6]
Stenorhynchus seticornis is commonly found in the shallow sub-tidal on rock bottoms, corals, calcareous algae, and also on soft sediments, such as shelly gravel and sand. Its geographical distribution is restricted to the Occidental Atlantic, from North Carolina to Argentina. [7] Stenorhynchus seticornis is found in the western Atlantic Ocean, from North Carolina and Bermuda to Brazil, including throughout the Caribbean Sea,. [5] It lives on coral reefs at depths of 10–30 feet (3.0–9.1 m). [8]
S. seticornis is nocturnal and territorial. [9] The species has displayed notable negative phototaxis, meaning the organism prefers to avoid sunlight, [10] and changes location during the day and nighttime. [10] It eats small feather duster worms and other coral reef invertebrates. [9] This crab is commonly kept in reef aquariums to control bristle worm populations. [11]
S. seticornis is one of a number of different invertebrates that are found living in association with the sea anemone, Lebrunia danae . It is often found among the anemone's pseudotentacles along with Pederson's cleaning shrimp ( Ancylomenes pedersoni ) and the spotted cleaner shrimp ( Periclimenes yucatanicus ). [12] The species is also notable for its propensity to decorate its body by attaching materials as camouflage, or if the attached organisms are noxious, to ward off predators through aposematism. [13] [14] There have been a considerable number of reports regarding cleaning symbiosis among reef fish, moray eels, and squirrelfish. [6] This is a somewhat unexpected relationship as moray eels and squirrelfish can be considered dangerous clients, because crabs are important elements of their diets. [6] This behavior has only been observed in the natural environment in Brazilian waters but it is believed that this behavior also exists throughout its distribution. [6]
During mating, the male places a spermatophore on the female, which she uses to fertilise her eggs. These fertilised eggs are then carried on the female's pleopods until they are ready to hatch into zoea larvae. [9] These swim towards the ocean surface and feed on plankton. They grow through a series of moults, and eventually metamorphose into the adult form. [9] When mature, the spermatozoa of S. seticornis show five lateral arms, similar to the sperm morphology of Inachus phalangium. [15]
Climate majorly regulates the breeding period of the arrow crab. Seasonal variation of water temperature and sunlight duration are considered as the most important variables determining the breeding period of arrow crabs. [16]
There is a positive relationship between fecundity and the size of the parental female. [7] In fact, the size of the female is the key variable in determining the number of eggs per batch. The female also determines the reproductive output of arrow crabs. [17]
Larvae that have grown in shallow water differ from larvae that grow in deeper water. The key difference is in the setation of the endopodite of the maxilla. [18]
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers on each arm. They first appeared during the Jurassic period, around 200 million years ago.
Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an asymmetric abdomen concealed by a snug-fitting shell. Hermit crabs' soft (non-calcified) abdominal exoskeleton means they must occupy shelter produced by other organisms or risk being defenseless.
The halloween hermit crab, also known as the striped hermit crab or orange-legged hermit crab, is a brightly colored aquatic hermit crab of the family Diogenidae. Besides its ability to routinely clean algae in aquaria, the halloween hermit crab's festive striped coloration also appeals to enthusiasts; it is considered the most brightly colored hermit crab in normal aquarium use.
The Majoidea are a superfamily of crabs which includes the various spider crabs.
Decorator crabs are crabs of several different species, belonging to the superfamily Majoidea, that use materials from their environment to hide from, or ward off, predators. They decorate themselves by sticking mostly sedentary animals and plants to their bodies as camouflage, or if the attached organisms are noxious, to ward off predators through aposematism.
Thor amboinensis, commonly known as the squat anenome shrimp or sexy shrimp, is a species of shrimp found across the Indo-West Pacific and in parts of the Atlantic Ocean. It lives symbiotically on corals, sea anemones and other marine invertebrates in shallow reef communities.
Latreilliidae is a small family of crabs. They are relatively small, long-legged crabs found on soft bottoms at depths of up 700 metres (2,300 ft) in mostly tropical and subtemperate waters around the world. Their carapace is very small and doesn’t cover the bases of their legs, which protrude from the cephalothorax in a spider-like manner. The family and its type genus are named after Pierre André Latreille. The oldest known fossils from the Latreillidae have been dated to the middle of the Cretaceous period. It comprises seven extant species.
Dardanus pedunculatus, commonly referred to as the anemone hermit crab, is a species of hermit crab from the Indo-Pacific region. It lives at depths of up to 27 m and collects sea anemones to place on its shell for defence.
Hepatus epheliticus, known by various names, including the calico crab and Dolly Varden crab, is a species of crab. It lives in shallow water in the western Atlantic Ocean from the Chesapeake Bay to the Dominican Republic. It has a 3-inch (76 mm)–wide carapace adorned with large red spots with darker outlines.
Inachus phalangium, Leach's spider crab, is a species of crabs from the north-eastern Atlantic Ocean and Mediterranean Sea. It is up to 20.5 mm (0.81 in) wide, and is very similar to other species in the genus Inachus.
Dyspanopeus sayi is a species of mud crab that is native to the Atlantic coast of North America. It has also become established outside its native range, living in Swansea Docks since 1960, the Mediterranean Sea since the 1970s, the North Sea since 2007 and the Black Sea since 2010. It can reach a carapace width of 20 mm (0.8 in), and has black tips to its unequal claws. It feeds on bivalves and barnacles, and is in turn eaten by predators including the Atlantic blue crab, Callinectes sapidus. Eggs are produced from spring to autumn, the offspring reach sexual maturity the following summer, and individuals can live for up to two years. The closest relative of D. sayi is D. texanus, which lives in the Gulf of Mexico; the two species differ in subtle features of the genitalia and the last pair of walking legs.
Libinia ferreirae is a species of tropical spider crab in the family Epialtidae. It is found on the seabed in shallow waters off the Atlantic coast of South America.
Dardanus venosus, the starry-eyed crab or stareye crab, is a species of hermit crab in the family Diogenidae. It occurs in shallow water on the eastern coasts of America from Florida southward to Brazil. It is sometimes kept in reef aquaria.
Pyromaia tuberculata is a species of crab in the family Inachoididae.
Lebrunia neglecta is a species of sea anemone in the family Aliciidae. It is found in the Caribbean Sea and Gulf of Mexico.
Mithraculus cinctimanus is a species of crab in the family Majidae. It is found in the Caribbean region and is usually associated with a sea anemone, sponge or coral.
Lebrunia coralligens, commonly known as the hidden anemone, is a species of sea anemone in the family Aliciidae. It is found in shallow water in the Bahamas, the Caribbean, and Brazil. It lives in fissures in corals and rocks.
Self-decoration camouflage is a method of camouflage in which animals or soldiers select materials, sometimes living, from the environment and attach these to themselves for concealment.
Hepatus pudibundus, the flecked box crab, is a crab from the class Malacostraca. They are found in the Atlantic Ocean with Brazil having a dense population of H. pudibundus, as they are one of the most commonly seen crabs in the country. Many of the studies done on H. pudibubus have occurred in the Ubatuba region of Brazil, where there is a rapid expansion of tourism that is affecting marine ecosystems.
Libinia spinosa is a majoid crab found in mud and sand bottoms of the Southwestern Atlantic and Pacific oceans. It is a generalist feeder on organisms such as algae, sponges, cnidarians, mollusks, polychaetes, crustaceans, and small fish. It commonly engages in a symbiotic relationship with the medusa Lychnorhiza lucerna.
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