Did you know that the Armed Nylon Shrimp (Heterocarpus ensifer) was featured on a Palau stamp in 1993? This deep water shrimp can be found in much of the Atlantic ocean at depths of 200m-880m deep. When threatened, this shrimp will "vomit" a cloud of bioluminescent fluid, startling predators and attracting bigger predators to attack the original threat while the shrimp escapes.
Although they look like they belong on the runway, the elegant squat lobster's vivid coloration is actually a form of camoflage. These tiny crustaceans live on plant-like creatures called crinoids, or feather stars. Their hosts are brightly colored, so to blend in Allogalathea elegans pulls out all the stops!
(Image: An elegant squat lobster (Allogalathea elegans) by Ryan Paddy)
Anatomy: 10 legs, up to 38 appendages overall; many species have one pair of legs with enlarged pinchers, called chelae; large carapace; fanned out telson used for swimming (folded under the abdomen in crabs and some other species)
Diet: most are omnivorous scavengers; some are predators; some are primarily algae-eating herbivores
Habitat: marine, brackish, and freshwater environments worldwide; some species are terrestrial, mainly in tropical, humid environments
Evolved in: Devonian
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Decapoda contains the largest living arthropods: the Japanese Spider Crab (Macrocheira kaempferi) with a legspan of up to 4 metres (13 ft) long, and the American Lobster (Homarus americanus), which can weigh up to 20 kilograms (44 lb).
Luciferidae is a family of tiny, planktonic prawns, named for their bioluminescence. The first genus discovered was named Lucifer, Latin for “light bearer”. The second genus discovered was named Belzebub, a reference to its satanic-themed cousin rather than its bioluminescent ability.
Many different (often unrelated) species of shrimp and prawns have the common name “cleaner shrimp”, due to their cleaning symbiosis with fish and other marine animals. Cleaner shrimp will flag down client fish with their claws or by dancing, and then clean them of parasites and dead scales, getting a free meal in the process. They are especially helpful at cleaning out the wounds of client fish, reducing the risk of infection. In many coral reefs, cleaner shrimp congregate at cleaning stations, where aquatic wildlife will gather and wait to be cleaned. Up to 25 shrimp may live in close proximity at these stations, working together.
The Cardinal Shrimp or Sulawesi Shrimp (Caridina dennerli) is a popular freshwater aquarium shrimp, however, it is critically endangered and possibly extinct in the wild. Threats in the wild include pollution from nickel mining and other human disturbances, introduced species like the “Flowerhorn Cichlid”, and hydro-electric power plants on the southern shore of Lake Matano, their native habitat. Although previously locally abundant, no Caridina dennerli have been recorded in the wild since 2013.
Shrimp of the family Alvinocarididae are extremophiles, and are some of the few animals that are native to deep sea hydrothermal vent regions, and hydrocarbon cold seep environments. Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges, and are commonly volcanically active. The water which emerges from these vents can range from 60 °C (140 °F) to as high as 464 °C (867 °F).
Other decapods which are native to hydrothermal vents include the Yeti Lobsters, or Yeti Crabs (genus Kiwa). These decapods have a thick covering of “hairs” (setae) on their claws, which they use primarily for farming bacteria, their main food source. Yeti Lobsters wave their claws around near cold seeps, stirring up water to ensure the bacteria that live on their claws receive enough chemicals that will allow them to grow. By farming their own food, the Yeti Lobster has a readily available resource of food in the harsh environment of the deep sea.
Harlequin Shrimp (Hymenocera picta) (image 4) are predators of starfish, and are one of the few animals able to feed on Crown-of-Thorns Starfish (Acanthaster planci), though it can take days for the shrimp to take down such a large prey item. They usually hunt in pairs, one male and one female. Harlequin Shrimp are highly important to the ecology of coral reefs, as they reduce the Crown-of-Thorns’ consumption of coral.
Pistol Shrimp (family Alpheidae) are so named for their asymmetrical claws, the larger of which can snap so quickly and with such force that it creates a cavitation bubble that shoots forward, making a loud snapping sound which has measured in at 218 decibels (louder than a bullet). The velocity at which this bubble leaves their claw generates heat that reaches up to 4,427 °C (8,000 °F). The “bubble bullet” is mainly used for hunting prey: small fish. When in colonies, the snapping of Pistol Shrimps are so loud it is known to interfere with sonar and underwater communication, and they are a major source of underwater noise.
Some Pistol Shrimp have a mutualistic symbiotic relationship with gobies, sharing a burrow. The burrow is built and tended by the Pistol Shrimp, while the goby, having better vision, keeps watch for predators. When both are out of the burrow, the shrimp maintains almost constant contact with the goby using its antennae. The goby alerts the shrimp of danger with a characteristic tail movement, so that both can quickly retreat to the safety of their shared burrow.
The pistol shrimp species Synalpheus regalis is eusocial, living in the internal canals of a host sponge in colonies of over 300 individuals with 1 reproductive queen. Larger individuals guard the colony from intruders. This is the first known case of eusociality in a marine animal.
In many countries, mainly the US and the UK, lobster is considered a delicacy. The most common way of killing crustaceans for food is boiling them alive in water. Boiling has been found to cause extreme suffering in lobsters, crayfish, and crabs (which studies have shown are sentient and do experience pain) and they will continue to show intense brain activity for 30 to 150 seconds after immersion in boiling water. Slowly raising the water temperature may also cause pain in crustaceans over a longer period of time. Boiling lobsters has been banned in several jurisdictions, including Switzerland, New Zealand, and parts of Italy.
Typically, lobsters are dark colored, either bluish-green or greenish-brown, to blend in with the ocean floor, but multiple rare colorations have been discovered. These include albino, “cotton candy”, blue, calico, orange, split-colored, “Halloween”, red, and yellow.
The Superfamily Glypheoidea was originally considered to be a purely fossil group. That had to be changed when a single male specimen was discovered in the collections of the Smithsonian Institution in 1975. It had been caught off the Philippines in 1908 and preserved, without its full significance being realised. Over sixty years later, the specimen was rediscovered, and described by two French scientists as a new genus and species, Neoglyphea inopinata in 1975, meaning "unexpected new Glyphea". Previously, this superfamily, which arose in the Triassic, was thought to have gone extinct by the Eocene. This is an example of a “lazarus taxon,” a taxon that disappeared from the fossil record only to be rediscovered living in a later era, and also makes Neoglyphea (as well as the more newly discovered Laurentaeglyphea) true “living fossils”.
Almost 800 species of Hermit Crab (superfamily Paguroidea) carry mobile shelters (most often calcified snail shells), which they use to protect their soft, asymmetric abdomen. As the crab molts and grows, it needs to find larger shells to fit its growing body. Hermit crabs may engage in a social behavior in which a hermit crab attempts to exchange its shell with that of another hermit crab, presumably to obtain a better shell fit. Several hermit crab species, both terrestrial and marine, have been observed forming a vacancy chain to exchange shells, where the crabs will line up by size and each move into the shell a size up. However, since suitable intact gastropod shells are sometimes a limited resource, competition can often occur between hermit crabs for shells, and hermit crabs may fight or even kill a competitor for a suitable shell. Along with some gastropod populations dwindling in certain areas, beachcombers and shell collectors have made it increasingly more difficult for hermit crabs to find new shelters.
Some of the larger marine species of hermit crab support one or more sea anemones on their shell. This is a mutualistic relationship, as the stinging anemone can scare away the hermit crab’s predators, and feed on leftovers from the hermit crab’s meals. Hermit crabs of the family Parapaguridae do not even carry empty gastropod shells, instead carrying colonies of a dozen or more sea anemones or zoanthids.
The Coconut Crab (Birgus latro) is a terrestrial species of giant hermit crab, and the largest terrestrial arthropod known, with a weight of up to 4.1 kg (9 lb) and legspan that can be as wide as 1 m (3 ft 3 in). While juvenile Coconut Crabs carry shells like other hermit crabs, adults develop a tough exoskeleton on their abdomen and stop carrying a shell. They feed primarily on fruits, nuts, and seeds, but will also eat carrion opportunistically. This has led to the popular internet conspiracy theory that Amelia Earhart crash-landed on Nikumaroro, and wasn’t found due to her remains being scavenged by Coconut Crabs. However, Coconut Crabs generally do not scavenge bones… or airplanes, for that matter, and no evidence of Earhart’s plane has been found on or near Nikumaroro, so this theory is generally discredited by historians.
The giant ✨shiny✨ crab Tamatoa, from Disney’s Moana, is a Coconut Crab.
Crabs of the family Homolidae are known as Carrier Crabs because they are known to carry around other animals such as sponges, black corals, soft corals, and sea urchins, likely as a defense mechanism against predators where they will either use the animal as a shield or a distraction.
Several species of Gorilla Crabs (family Xanthidae) are highly poisonous, containing paralytic shellfish toxin (PST), tetrodotoxin (TTX), and/or palytoxin (PLTX), which are not destroyed by cooking and for which no antidote is known.
The Christmas Island Red Crab (Gecarcoidea natalis) is a species of land crab that is endemic to Christmas Island and Cocos (Keeling) Islands in the Indian Ocean. The. Christmas Island Red Crab is terrestrial, and spends most of its life in the inland forests of the islands, but starts its life as a larvae at sea. Thus, these crabs are known for their annual mass migration to lay their eggs in the ocean, carpeting the ground in millions of crabs for miles. The crabs have to cross several roads to get from the forests, to their breeding grounds, and back again, and thousands of red crabs may end up crushed during the migration event, or may even cause accidents themselves as their thick exoskeletons puncture tires. To ensure the safety of both the crabs and humans, Christmas Island park rangers must work to ensure that the crabs can safely make their journey from the center of the island to the sea, directing traffic and setting up bridges and underpasses for the crabs.
The Light-blue Soldier Crab (Mictyris longicarpus) is considered "one of the most loved crabs in Australia". These tiny blue crabs spend most of their time buried in the sand, emerging to the surface a few hours before low tide. The crabs will perform somersaults to dislodge sand from their carapace, and then begin walking together towards the water in an almost straight line. With the larger individuals leading the “charge”, the army of soldier crabs will march up and down the beach in a line, feeding together on detritus and small organisms in the sand. After 1 to 2.5 hours, the army breaks up and the individual crabs travel up the shore, and dig themselves back into the sand in a unique corkscrew motion. Naturalist Michael Tweedie considered these crabs representatives of an aspect of human society, comparing them to "cheerful bohemians, living crowded together and out-doing in unrepressed and irresponsible behavior even those human communities which aspire most strenuously towards this ideal".
A 2023 study using the well known mirror test found that the Atlantic Ghost Crab (Ocypode quadrata) seems to be capable of recognizing itself in a mirror. The study's author concluded that the data indicate that the crabs have "a rudimentary form of self-awareness".
i dunno if youve done it before, but what about Cambarellus Diminutus, AKA the least crayfish. Its the smallest crayfish out there with males reaching only 2.5cm and females getting up to 4cm at times, usually only around 3 though.
I love crawdads, thank you for the request!
Have you seen the least crayfish (Cambarellus diminutus)?
Big Sandy Crayfish (Cambarus callainus), family Cambaridae, found in streams and rivers in the Big Sandy Watershed of the Appalachians in the Eastern U.S.
THREATENED.
photograph by Brett Billings/USFWS
USFWS Fisheries
