| Squilla empusa | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Stomatopoda |
| Family: | Squillidae |
| Genus: | Squilla |
| Species: | S. empusa |
| Binomial name | |
| Squilla empusa | |
Squilla empusa is a species of mantis shrimp found in coastal areas of the western Atlantic Ocean. It excavates and occupies a burrow in soft sediment from which it emerges, mainly at night, to feed on fish and invertebrate prey.
Squilla empusa grows to a length of about 30 cm (12 in). The head bears stalked compound eyes which can move separately to scan the surroundings. The head and thorax are fused into a cephalothorax which is protected by a shield-like carapace. The thorax has eight segments each bearing a pair of appendages. The front pair are slender and used for grooming whereas the second pair are large, raptorial claws that can slash and spear prey. [2] The third, fourth and fifth pairs each have a flattened terminal segment. They are known as maxillipeds and are used to move food to the mouth. The sixth, seventh and eighth pairs are unspecialised walking legs known as pereiopods. The abdomen has six segments, the front five each having a pair of pleopods (swimming legs). These are biramous (branched) and bear filamentous gills. The sixth segment bears a pair of large uropods which, together with the flexible, six-spiked telson, forms a broad tailfan. [2] [3]
Squilla empusa is reported from the eastern seaboard of the United States with a range extending from Cape Cod to the Gulf of Mexico. It is also reported from Brazil and the Mediterranean Sea. It lives in a U-shaped burrow in soft sediment on the seabed at depths from the intertidal zone down to about 150 m (500 ft). [2]
The summer burrow of Squilla empusa consists of a tube with typically two openings connected by a horizontal tunnel some 15 to 50 cm (6 to 20 in) below the surface of the sediment. The horizontal section normally has two bends and a diameter of up to 10 cm (4 in), depending on the size of the occupant. In the more northerly parts of its range, this mantis shrimp excavates a vertical burrow in the winter up to 4.1 m (13 ft) deep. At this depth in the sediment, the oxygen content of the water decreases and the temperature rises. This behavioural adaptation may enable Squilla empusa to inhabit locations where the water temperature falls too low in winter for it otherwise to survive. [4]
Two main methods of burrowing are employed. A vigorous fanning action of the pleopods causes particles of sediment to become suspended and the current produced pushes the plume backwards past the telson. Using this method, an animal can create a depression as large as itself within two minutes. It then turns round and use its maxillipeds to form a basket with which it carries lumps of sediment away from the excavation. This is a slower process but sustainable for a longer period. Further burrowing creates the typical tunnel with one or more openings, and this is frequently remodelled, often in the course of a few hours. Squilla empusa can dig to a depth of 20 cm (8 in) in less than an hour. When the animal is inside the burrow it sometimes uses its maxillipeds to create a current of water flowing through. [5] This species is territorial and will defend its burrow from other mantis shrimps. [2]
Squilla empusa is mainly nocturnal and feeds on fish, shrimps, crabs, krill, worms, molluscs and other mantis shrimps. The raptorial claws are unfolded with great rapidity to spear, slash and immobilise the prey, which is brought back inside the burrow when caught. [2]
Dendrobranchiata is a suborder of decapods, commonly known as prawns. There are 540 extant species in seven families, and a fossil record extending back to the Devonian. They differ from related animals, such as Caridea and Stenopodidea, by the branching form of the gills and by the fact that they do not brood their eggs, but release them directly into the water. They may reach a length of over 330 millimetres (13 in) and a mass of 450 grams (1.0 lb), and are widely fished and farmed for human consumption.
Mantis shrimp, or stomatopods, 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 450 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.
Malacostraca is the largest of the six classes of crustaceans, 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.
Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this pouch and are not free-swimming characterises the order. The mysid's head bears a pair of stalked eyes and two pairs of antennae. The thorax consists of eight segments each bearing branching limbs, the whole concealed beneath a protective carapace and the abdomen has six segments and usually further small limbs.
Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax.
The order Notostraca, containing the single family Triopsidae, is a group of crustaceans known as tadpole shrimp or shield shrimp. The two genera, Triops and Lepidurus, are considered living fossils, with similar forms having existed since the Devonian. They have a broad, flat carapace, which conceals the head and bears a single pair of compound eyes. The abdomen is long, appears to be segmented and bears numerous pairs of flattened legs. The telson is flanked by a pair of long, thin caudal rami. Phenotypic plasticity within taxa makes species-level identification difficult, and is further compounded by variation in the mode of reproduction. Notostracans are omnivores living on the bottom of temporary pools and shallow lakes.
The decapod is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various groups these may be reduced or missing. They are, from head to tail:
The crustacean order Tanaidacea make up a minor group within the class Malacostraca. There are about 940 species in this order.
Caprellidae is a family of amphipods commonly known as skeleton shrimps. Their common name denotes the threadlike slender body which allows them to virtually disappear among the fine filaments of seaweed, hydroids and bryozoans. They are sometimes also known as ghost shrimps.
Triops longicaudatus is a freshwater crustacean of the order Notostraca, resembling a miniature horseshoe crab. It is characterized by an elongated, segmented body, a flattened shield-like brownish carapace covering two thirds of the thorax, and two long filaments on the abdomen. The genus name Triops comes from Ancient Greek ὤψ or ṓps, meaning "eye" prefixed with Latin tri-, "three", in reference to its three eyes. Longicaudatus is a Latin neologism combining longus ("long") and caudatus ("tailed"), referring to its long tail structures. Triops longicaudatus is found in freshwater ponds and pools, often in places where few higher forms of life can exist.
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 implemented 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.
Oratosquilla oratoria, the Japanese mantis shrimp, is a species of mantis shrimp found in the Western Pacific. It is widely harvested in Japan where it is known as shako 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).
Angustidontus is a genus of predatory pelagic crustaceans from the Late Devonian and Early Carboniferous periods, classified as part of the subclass Eumalacostraca. Fossils of the genus have been recovered in relative abundance from Canada, Germany, the Czech Republic, Poland, Belarus, Ukraine and large parts of the United States, including Oklahoma, Ohio, Indiana, Kentucky, Montana, Utah, Nevada.
Platysquilla eusebia is a species of mantis shrimp in the family Nannosquillidae, from the Mediterranean Sea and north-eastern Atlantic Ocean. It is a spearer, and grows up to 7 cm (2.8 in) long.
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.
Polycheles typhlops is a species of blind, deep water decapod crustacean with a cosmopolitan distribution. It is "one of the dominant and most characteristic crustaceans in deep-sea communities of the Mediterranean Sea".
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.
Coxoplectoptera or "chimera wings" is an extinct order of stem-group mayflies containing one family, Mickoleitiidae.
Crustaceans form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, 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. Some crustaceans are more closely related to insects and the other hexapods than they are to certain other crustaceans.
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