''Odontodactylus scyllarus'', commonly known as the peacock mantis shrimp, harlequin mantis shrimp, painted mantis shrimp, clown mantis shrimp, rainbow mantis shrimp, or simply mantis shrimp, is a large Stomatopod native to the

epipelagic The photic zone (or euphotic zone, epipelagic zone, or sunlight zone) is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological ...

seabed The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as seabeds. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

across the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

, ranging from

the Marianas The Mariana Islands ( ; ), also simply the Marianas, are a crescent-shaped archipelago comprising the summits of fifteen longitudinally oriented, mostly Volcano#Dormant and reactivated, dormant volcanic mountains in the northwestern Pacific Ocean ...

East Africa East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...

, and as far South as Northern KwaZulu Natal in

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

. There are roughly 480 species of Stomatopod. These crustaceans are well known for their raptorial claws, exceptional vision, and their unique way of interacting with other marine species. In the marine aquarium trade, it is both prized for its attractiveness and considered by others to be a dangerous pest.

Description

''O. scyllarus'' is one of the larger, more colourful

mantis shrimp Mantis shrimp are carnivorous marine crustaceans of the order Stomatopoda (). Stomatopods branched off from other members of the class Malacostraca around 400 million years ago, with more than 520 extant species of mantis shrimp known. All li ...

s commonly seen, ranging in size from . They are primarily green with orange legs and

leopard The leopard (''Panthera pardus'') is one of the five extant cat species in the genus ''Panthera''. It has a pale yellowish to dark golden fur with dark spots grouped in rosettes. Its body is slender and muscular reaching a length of with a ...

-like spots on the

anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

. Their ability to see circularly polarised light has led to studies to determine if the mechanisms by which their eyes operate can be replicated for use in reading CDs and similar

optical storage Optical storage refers to a class of data storage systems that use light to read or write data to an underlying optical media. Although a number of optical formats have been used over time, the most common examples are optical disks like th ...

devices.

The dactyl club

One predatorily addition of the mantis shrimp is their hammer-like appendage, the dactyl club. This is the most electron-dense region of the stomatopod exoskeleton. It is reported to have a "punch" of over 50 miles per hour (80 km/h), the fastest recorded punch of any living animal. The acceleration is similar to that in a .22 LR

bullet A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constru ...

fired from a

handgun A handgun is a firearm designed to be usable with only one hand. It is distinguished from a long gun, long barreled gun (i.e., carbine, rifle, shotgun, submachine gun, or machine gun) which typically is intended to be held by both hands and br ...

(accelerations of over 100,000 m/s² or 330,000 ft/s² (more than 10,000 g), and speeds of over 20 m/s or 66 ft/s), with each strike packing 1,500 N (340 lb_f) of force. Mechanically, the dactyl club is a spring-loaded weapon. From a transverse cross-section, the club can be divided into three different regions: the impact region, the periodic region and the striated region. The mechanical properties of each region has a correlation to the degree of mineralization that is present. There is a step-like decrease in calcium concentration from the impact region towards the periodic region of the dactyl club, meanwhile the phosphate concentration decreases in a gradient manner. Alongside this the carbon and magnesium concentrations increases in the same region, hence stipulating that the impact region is mainly composed of calcium phosphate while the rest of the club contains a combination of

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

phosphate and

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

. The impact region has shown to be mainly composed of

hydroxyapatite Hydroxyapatite (International Mineralogical Association, IMA name: hydroxylapatite) (Hap, HAp, or HA) is a naturally occurring mineral form of calcium apatite with the Chemical formula, formula , often written to denote that the Crystal struc ...

, with a higher degree of crystallinity compared to that found in bovine bone, which is what lessens the brunt of impact. Compared to other appendages, this structure is five-times as thick and increases solidity of the club at the point of contact.

Exceptional vision

Their eyes possess 12 photoreceptors which is the largest amount of photoreceptor types in any animal. These photoreceptors allow these sea creatures to distinguish color and linear and circular polarized light. With these, Stomatopods inhabit coral reefs as they are full of color. The Odontodactylus' eyes are made up of ventral and dorsal regions which are separated by a midband. This midband contains 6 rows of ommatidia. Row 1-4 involve color processing while 5-6 involve circular and linear polarized light.

Ecology

''Odontodactylus scyllarus'' is a burrower, constructing U-shaped holes in the loose substrate near the bases of

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

s in water ranging from deep in the benthic zone of the ocean. ''O. scyllarus'' is a '' smasher'', with club-shaped

raptorial In biology (specifically the anatomy of arthropods), the term ''raptorial'' implies much the same as ''predatory'' but most often refers to modifications of an arthropod leg, arthropod's foreleg that make it function for the grasping of prey whi ...

appendage An appendage (or outgrowth) is an external body part or natural prolongation that protrudes from an organism's body such as an arm or a leg. Protrusions from single-celled bacteria and archaea are known as cell-surface appendages or surface app ...

s. An agile and active intertidal and sub-intertidal

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

, it prefers

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s, and

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

s, and will repeatedly deliver blunt force to the

exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. human skeleton, that ...

of its prey until it can gain access to the underlying soft tissue for consumption. It is reported to have a "punch" of over , the fastest recorded punch of any living animal. The acceleration is similar to that in a .22 LR

fired from a

(accelerations of over (more than 10,000 g), and speeds of over ), with each strike packing of force. The speed of a raptorial appendage's strike causes cavitation bubbles to form. When those bubbles pop they release a large amount of heat, temporarily raising temperatures and weakening the armor of their prey. In addition, the surface of its hammer-claw is made up of extremely dense

, laminated in a manner that is highly resistant to fracturing and can break ordinary glass

tank A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and battlefield mobility provided by tracks and a powerful engine; ...

s. Its composition is being investigated for potential

bionic Bionics or biologically inspired engineering is the application of biological methods and systems found in nature to the study and design of engineering systems and modern technology. The word ''bionic'', coined by Jack E. Steele in August 19 ...

use in material engineering.

Aquaria

Some saltwater aquarists keep peacock mantis shrimp in captivity. The peacock mantis is especially colourful and desired in the trade. While some aquarists value peacock shrimp, others consider them harmful pests because they are voracious predators that will eat other desirable inhabitants in the tank. Some of the largest specimens can break aquarium glass by striking it and can do further damage by burrowing in live rock. Live rock with mantis shrimp burrows is considered useful by some in the marine aquarium trade and is often collected. It is not uncommon for a piece of live rock to convey a live mantis shrimp in an aquarium. Once inside the tank, they may feed on fish, shrimps, and other inhabitants. They are notoriously difficult to re-catch once established in a well-stocked tank, and there are accounts of them breaking glass tanks and damaging

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

when they wish to make a home within it.

References

External links

Mantis shrimps could show us the way to a better DVD
* {{Taxonbar, from=Q43735 Stomatopoda Crustaceans described in 1758 Taxa named by Carl Linnaeus Edible crustaceans