| Pagurus longicarpus | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Anomura |
| Family: | Paguridae |
| Genus: | Pagurus |
| Species: | P. longicarpus |
| Binomial name | |
| Pagurus longicarpus | |
Pagurus longicarpus, the long-wristed hermit crab, is a common hermit crab found along the Atlantic and Gulf coasts of the United States and the Atlantic coast of Canada. [2]
This species of hermit crab can reach a shell length of up to half an inch in size. P. longicarpus coloration can vary, but body color is most commonly gray, green or white. The right claw of P. longicarpus is much larger than the left, and each claw has a tan or gray stripe down the middle. [3]
The long-wristed hermit crab inhabits the empty shells of gastropods such as periwinkles, snails, and slugs for mobile shelter and protection of their soft abdomens. They anchor themselves into the shells by wrapping their abdomens around the columella, or axis, inside the vacant shell. [4] Hermit crabs cannot produce their own shells, and therefore must scavenge for abandoned ones. [5] [6] [7] Shell selection plays many crucial roles in P. longicarpus, such as providing protection from predators, desiccation and salinity stress, as well as influencing competition, population size, and reproductive behaviors in the species. [6]
Pagurus longicarpus is commonly found along the Atlantic coast of Canada and the United States, from Nova Scotia to Northeastern Florida, as well as along the Gulf coast of the United States to Texas. [2] These hermit crabs can be found in intertidal and subtidal Atlantic environments on a variety of substrates and at depths of up to 200 meters. [8] Most commonly, P. longicarpus is found in shallow tidal pools during the months of April to October, and in deeper and warmer waters during the fall and winter months. P. longicarpus faces extreme temperature and salinity fluctuations while inhabiting tidal pools due to the rising and falling tides, as well as changing climate. [6] On hot, sunny days, there is often a rapid increase in tidal pool temperature and salinity, whereas on cooler, rainier days, salinity and temperature can rapidly decrease. Rising tides can also alter tidal pool conditions to those of the surrounding ocean. [6] Due to these harsh living conditions, P. longicarpus depends heavily on its shell to cope with changing conditions. These fluctuating conditions can also impact shell selection in the species and determine species distribution within intertidal and subtidal regions. [2] [6]
According to Neumann, Knebelsberger, Barco and Haslob (2022), P. longicarpus has become established in the North Frisian Wadden Sea. This may have occurred due to trans-Atlantic transport of larvae in ballast water. [9]
Long-wristed hermit crabs are scavenger feeders with a broad diet consisting of detritus, organic material found in ocean surface foam, microcrustaceans and algae. [8] [10] Feeding is performed by scooping sand or other substrate with the chelipeds, ripping and tearing food, and then passing it to the mouth for consumption. [11]
The major predators of P. longicarpus include birds, fish, snails, octopuses and other crabs, including the green crab. [3] [7] Hermit crab shells are crucial for protection and minimizing predation, and therefore proper shell selection is vital. P. longicarpus will avoid selecting shells with extensive damage because they are more vulnerable to predation. The most common type of damage to hermit crab shells is the presence of small holes. These holes are caused by the drilling of nacticid gastropods in order to prey on the original gastropod hosts of the shell. [7]
Intraspecific competition within this species is very common and is most often triggered by lack of resources. [12] One of the most important limited resources to hermit crabs is their shell, which is key to their survival and reproductive success. Finding an appropriately sized shell is valuable for P. longicarpus. From an energetic standpoint, if a shell is too large, crabs will extend unnecessary energy carrying and maneuvering it. Alternatively, if the shell is too small, they could suffer from increased predation and desiccation. [6] Shell selection also plays a role in reproductive success in P. longicarpus. Reproductive success is positively correlated with a larger shell size, and the rate of growth of the crabs can be stimulated by inhabiting larger shells. [5] P. longicarpus also will not feed unless housed in the proper sized shell, ultimately leading to starvation and death. [4] Each of the consequences of incorrect shell size places a strong selective pressure on obtaining the perfect shell, which often results in aggressive and competitive interactions within the species. [12] In addition to fighting over mates and food, P. longicarpus will fight over shells. Larger crabs or crabs with less suitable shells will often forcibly remove other crabs with more desirable shells by clasping the chelae, or legs, of the occupant with its pincers, which allows them to takeover the desired shell. [4] [12] Along with predation, shell availability is a major factor in determining P. longicarpus population size. [7]
P. longicarpus breeding season occurs from late March until October with the peak breeding in April. The main period of reproduction in the species occurs during the spring. [8] Male hermit crabs will compete with other males for available females during breeding season. P. longicarpus, like many crustaceans, performs precopulatory mate-guarding behaviors, where males will grasp ahold of the female's shell once the female releases a pheromone signaling sexual maturity. [13] Male and female crabs can be differentiated based on their pleopod morphology. Males have two pleopods, while females have three branching pleopods where her eggs are attached. [14] P. longicarpus have sexual internal fertilization and must exit their shells in order to mate. After fertilization, the female houses the eggs inside her shell where they grow and develop. Larvae are later released into the surrounding ocean where they undergo several planktonic growth stages before developing into adult hermit crabs. [3]
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.
Pagurus pollicaris is a hermit crab commonly found along the Atlantic coast of North America from New Brunswick to the Gulf of Mexico. It is known by a number of common names, including gray hermit crab, flat-clawed hermit crab, flatclaw hermit crab, shield hermit crab, thumb-clawed hermit crab, broad-clawed hermit crab, and warty hermit crab.
A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. These pools typically range from a few inches to a few feet deep and a few feet across. Many of these pools exist as separate bodies of water only at low tide, as seawater gets trapped when the tide recedes. Tides are caused by the gravitational pull of the sun and moon. A tidal cycle is usually about 25 hours and consists of one or two high tides and two low tides.
Squat lobsters are dorsoventrally flattened crustaceans with long tails held curled beneath the cephalothorax. They are found in the two superfamilies Galatheoidea and Chirostyloidea, which form part of the decapod infraorder Anomura, alongside groups including the hermit crabs and mole crabs. They are distributed worldwide in the oceans, and occur from near the surface to deep sea hydrothermal vents, with one species occupying caves above sea level. More than 900 species have been described, in around 60 genera. Some species form dense aggregations, either on the sea floor or in the water column, and a small number are commercially fished.
Coenobita cavipes is a species of land hermit crab native to the eastern parts of Africa, the Indonesia, Philippines, China, Japan, Malaysia, Taiwan, Polynesia, and Micronesia. While these hermit crabs are terrestrial, they prefer to reside near the shores for access of both water and land.
Pagurus novizealandiae, or the New Zealand hermit crab is a hermit crab of the family Paguridae, endemic to New Zealand. Its body is up to 16 millimetres (0.63 in) wide.
Calcinus elegans, also known as the blue line hermit crab, is a small, tropical hermit crab.
Diogenes pugilator is a species of hermit crab, sometimes called the small hermit crab or south-claw hermit crab. It is found from the coast of Angola to as far north as the North Sea, and eastwards through the Mediterranean Sea, Black Sea and Red Sea. Populations of D. pugilator may be kept in check by the predatory crab Liocarcinus depurator.
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.
Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow. The larvae of crustaceans often bear little resemblance to the adult, and there are still cases where it is not known what larvae will grow into what adults. This is especially true of crustaceans which live as benthic adults, more-so than where the larvae are planktonic, and thereby easily caught.
Pagurus sinuatus is a large species of hermit crab found in Australia and the Kermadec Islands. It is red or orange in colour with coloured bands on the legs and patches on the body.
Pagurus samuelis, the blueband hermit crab, is a species of hermit crab from the west coast of North America, and the most common hermit crab in California. It is a small species, with distinctive blue bands on its legs. It prefers to live in the shell of the black turban snail, and is a nocturnal scavenger of algae and carrion.
Calcinus tubularis is a species of hermit crab. It is found in the Mediterranean Sea and around islands in the Atlantic Ocean, where it lives below the intertidal zone. Its carapace, eyestalks and claws are marked with numerous red spots. C. tubularis and its sister species, C. verrilli, are the only hermit crabs known to show sexual dimorphism in shell choice, with males using normal marine gastropod shells, while females use shells of gastropods in the family Vermetidae, which are attached to rocks or other hard substrates.
Porcellana sayana is a species of porcelain crab that lives in the western Atlantic Ocean, often as a commensal of hermit crabs. It is red with white spots, and has a characteristic bulge behind each claw.
Pagurus forbesii is a species of hermit crab in the family Paguridae. It is found in the northeastern Atlantic Ocean and the Mediterranean Sea.
Pagurus acadianus, the Acadian hermit crab, is a species of hermit crab in the family Paguridae. It is found in Western Atlantic Ocean.
Neanthes fucata is a species of marine polychaete worm in the family Nereididae. It lives in association with a hermit crab such as Pagurus bernhardus. It occurs in the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea.
Pagurus dalli, commonly known as the whiteknee hermit or whiteknee hermit crab, is a species of hermit crab in the family Paguridae. It is found in the northeastern Pacific Ocean at depths down to about 276 m (900 ft). It usually lives in a mutualistic symbiosis with a sponge, or sometimes a hydroid.