| Gonodactylus chiragra | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Stomatopoda |
| Family: | Gonodactylidae |
| Genus: | Gonodactylus |
| Species: | G. chiragra |
| Binomial name | |
| Gonodactylus chiragra (Fabricius, 1781) | |
| Synonyms | |
Squilla chiragra Fabricius, 1781 | |
Gonodactylus chiragra is a medium to large mantis shrimp that is distributed widely throughout the West Indo-Pacific.
The synonymy of G. chiragra remains unclear because all members of Gonodactylus have been confused with G. chiragra at some point. [1] This species also displays a large amount of variation, which has made classification even more difficult. [2] Newer research by Manning has resulted in the discovery of several new species that were previously thought to be G. chiragra. [3]
The species typically grows to a maximum length of 105 millimetres and is sexually dimorphic. [4] Males range in color from brown to a dark green, and females from a grey/green to white. [5]
All mantis shrimp (stomatopods) are either spearers or smashers. G. chiragra is a smasher, which means that the heel on their second pair of thoracic appendages is greatly enlarged, forming a club that is used to smash prey. [6] When a target is spotted, G. chiragra strike powerfully and quickly in one of the quickest punches in all of nature. [7] Common targets for eating are snails, hermit crabs, and clams, but bigger animals are sometimes targeted such as mollusks and other crustaceans. [8] G. chiragra are one of the largest smashers and employ a unique fighting strategy in which they circle around the target and aim at the head. [6] This is thought to have developed as a result of intense competition for suitable burrows among stomatopods. [6]
The species is considered one of the most aggressive species of mantis shrimp and when in captivity, routinely strike glass walls and air tubes in the aquarium. [1]
Seeing underwater is very different because in the ambient light there is strong spectral variations that affect color vision. [9] The eyes of G. chiragra are some of the most unique in all of the animal world because they are sensitive to linear polarization. [10] Living underwater, this provides many benefits to them including increased contrast enhancement, ability to see polarization reflecting prey, and better navigation among the light-scattered ocean environment. [10]
The eyes themselves are large stalked apposition compound eyes and have two defining features that affect their complexity. [10] First is their rotational ability; the eyes move completely independent of each other and one eye only is enough for catching prey. [11] Second is the presence of a midband, a large strip of specialized ommatidia (clusters of photoreceptor cells) that divides each eye equally into two segments. [12] The midband contains specialized polarization receptors in rows five and six. In row 2D, photoreceptors have unidirectional microvilli, which makes them sensitive to linear polarized light. [10] The midband is also responsible for binocular distant vision. [11]
Although their eyes are incredibly complex among animals, G. chiragra are one of the few species of mantis shrimp that do not have polarized body markings. [10] This offers them one less form of communication, and it is thought that evolution of deadly weapons (see "Claws" above) was preferred to body signals because of their restricted habitat. [10]
The species is widely distributed in the western Indo-Pacific. [3] It occurs in shallow water in the upper intertidal zone around boulders and coral heads where prey is available. [13] G. chiragra are burrowers, but usually do not construct their own shelters. Instead, they inhibit rocky cavities that are either natural or created by other animals such as mollusks. [1] However, they are equipped to erode the material of the burrow so that it perfectly fits their body shape. [1] Burrows serve many purposes, including protection, lookouts for finding prey, consuming prey, mating, and keeping eggs safe. [1] G. chiragra are active during the day and often close off the entrance to their shelter at night using bits of sand and rocks. [8]
Mantis shrimp are carnivorous marine crustaceans of the order Stomatopoda. Stomatopods branched off from other members of the class Malacostraca around 340 million years ago. Mantis shrimp typically grow to around 10 cm (3.9 in) in length, while a few can reach up to 38 cm (15 in). A mantis shrimp's carapace covers only the rear part of the head and the first four segments of the thorax. Varieties range in colour from shades of brown to vivid colours, with more than 520 species of mantis shrimp known. They are among the most important predators in many shallow, tropical and subtropical marine habitats. However, despite being common, they are poorly understood, as many species spend most of their lives sheltering in burrows and holes.
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distinguish brightness and color. The image perceived by this arthropod eye is a combination of inputs from the numerous ommatidia, which are oriented to point in slightly different directions. Compared with single-aperture eyes, compound eyes have poor image resolution; however, they possess a very large view angle and the ability to detect fast movement and, in some cases, the polarization of light. Because a compound eye is made up of a collection of ommatidia, each with its own lens, light will enter each ommatidium instead of using a single entrance point. The individual light receptors behind each lens are then turned on and off due to a series of changes in the light intensity during movement or when an object is moving, creating a flicker-effect known as the flicker frequency, which is the rate at which the ommatidia are turned on and off– this facilitates faster reaction to movement; honey bees respond in 0.01s compared with 0.05s for humans.
Malacostraca is the second largest of the six classes of pancrustaceans just behind hexapods, containing about 40,000 living species, divided among 16 orders. Its members, the malacostracans, display a great diversity of body forms and include crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, amphipods, mantis shrimp, tongue-eating lice and many other less familiar animals. They are abundant in all marine environments and have colonised freshwater and terrestrial habitats. They are segmented animals, united by a common body plan comprising 20 body segments, and divided into a head, thorax, and abdomen.
Odontodactylus is a genus of mantis shrimp, the only genus in the family Odontodactylidae. Mantis shrimp of the genus Odontodactylus can not only detect circular polarisation of light, but can also detect polarised light reflecting off their telson and uropods.
Crangonidae is a family of shrimp, of the superfamily Crangonoidea, including the commercially important species Crangon crangon. Its type genus is Crangon. Crangonid shrimps' first pair of pereiopods have partially chelate claws that they use to capture their prey. They burrow shallowly into sediment on the sea floor, and feed on bivalves, crustaceans, polychaetes, and some small fish.
Odontodactylus scyllarus, commonly known as the peacock mantis shrimp, harlequin mantis shrimp, painted mantis shrimp, clown mantis shrimp or rainbow mantis shrimp, is a large stomatopod native to the epipelagic seabed across the Indo-Pacific, ranging from the Marianas to East Africa, and as far South as Northern KwaZulu Natal in South Africa.
The Lysiosquillidae or banded mantis shrimps are a family of mantis shrimp, comprising some of the largest known mantis shrimp species. The most common and best known species is Lysiosquillina maculata, the zebra mantis shrimp.
Agonistic behaviour is any social behaviour related to fighting. The term has broader meaning than aggressive behaviour because it includes threats, displays, retreats, placation, and conciliation. The term "agonistic behaviour" was first defined and used by J.P Scott and Emil Fredericson in 1951 in their paper "The Causes of Fighting in Mice and Rats" in Physiological Zoology.Agonistic behaviour is seen in many animal species because resources including food, shelter, and mates are often limited.
Squilla mantis is a species of mantis shrimp found in shallow coastal areas of the Mediterranean Sea and the Eastern Atlantic Ocean: it is also known as "pacchero" or "canocchia". Its abundance has led to it being the only commercially fished mantis shrimp in the Mediterranean.
Erythrosquilla is a genus of mantis shrimp, placed in its own family (Erythrosquillidae) and superfamily (Erythrosquilloidea) comprising two species:
Eurysquillidae is a family of mantis shrimp. Formerly placed in the superfamily Gonodactyloidea, it has since been recognised that eurysquillids are closer to families in the Squilloidea, and so Eurysquillidae has been placed in its own superfamily, Eurysquilloidea. The family was first described in 1977 by Raymond Manning.
Oratosquilla oratoria, the Japanese mantis shrimp, is a species of mantis shrimp found in the western Pacific. It is widely harvested in Japan and eaten as sushi. Like other members of its order it has a powerful spear, which it uses to hunt invertebrates and small fish. It grows to a length of 185 millimetres (7.3 in), and lives at depths of 10–100 metres (33–328 ft).
Lysiosquillina maculata, the zebra mantis shrimp, striped mantis shrimp or razor mantis, is a species of mantis shrimp found across the Indo-Pacific region from East Africa to the Galápagos and Hawaiian Islands. At a length up to 40 cm, L. maculata is the largest mantis shrimp in the world. L. maculata may be distinguished from its congener L. sulcata by the greater number of teeth on the last segment of its raptorial claw, and by the colouration of the uropodal endopod, the distal half of which is dark in L. maculata but not in L. sulcata. A small artisanal fishery exists for this species.
Gonodactylus smithii, also known as the purple spot mantis shrimp or Smith's mantis shrimp, is a species of the smasher type of mantis shrimp. G. smithii are the first animals discovered to be capable of dynamic polarization vision. They are identified by their distinctive meral spots ranging from maroon to purple with a white ring, though those that inhabit depths below 10 meters tend to be colored maroon. They also have raptorial dactyles, specialized forelimbs that are pigmented green and red, and antennal scales that are yellow.
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.
Crustaceans are a group of arthropods that are a part of the subphylum Crustacea, a large, diverse group of mainly aquatic arthropods including decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, opossum shrimps, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. The three classes Cephalocarida, Branchiopoda and Remipedia are more closely related to the hexapods than they are to any of the other crustaceans.
Acanthosquilla is a genus of stomatopod crustacean. The American carcinologist Raymond B. Manning named and first circumscribed the genus in 1963. As of 2018, the World Register of Marine Species recognizes the following eight species:
Acanthosquilla derijardi is a species of stomatopod crustacean. Its distribution is widespread throughout the Indo-West Pacific. The species was initially described by the American carcinologist Raymond B. Manning in 1970. Its junior synonym, A. sirindhorn, was named in 1995 in honor of Princess Sirindhorn of Thailand.
Hemisquilla is a genus of mantis shrimp, and the only genus in the family Hemisquillidae. It contains four species distributed in Australia and the Americas. Species in the genus typically eat snails, fish, rock oysters, and smaller crustaceans like crabs. They are preyed upon by larger bony fishes and cephalopods. It is the most basal living mantis shrimp lineage, and the sister group to all other mantis shrimp.
Hemisquilla californiensis is a species of mantis shrimp native to the northern Pacific.
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