Synalpheus microneptunus

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Synalpheus microneptunus
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Infraorder: Caridea
Family: Alpheidae
Genus: Synalpheus
Species:
S. microneptunus
Binomial name
Synalpheus microneptunus

Synalpheus microneptunus is a species of small snapping shrimp native to the waters off the island of Barbados. It is one of at least seven known species of eusocial shrimp. They are cryptofauna, living exclusively within the network of tunnels in the sponges Neopetrosia proxima and Neopetrosia subtriangularis . They form small colonies of six to fifteen individuals, usually with only a single breeding female.

Contents

Taxonomy

Synalpheus microneptunus belongs to the genus Synalpheus of the snapping shrimp family, Alpheidae. It was first described by Kristin M. Hultgren, Kenneth S. MacDonald III, and J. Emmett Duffy in 2011, from specimens collected from the Cement Factory Reef off the northwest coast of the island of Barbados. [1]

It is one of five closely related and morpholologically very similar species in the Synalpheus paraneptunus species complex. Synalpheus microneptunus can readily be distinguished from other members of the complex by the presence of four carpal segments on each of the second pair of walking legs (pereopods) on both adult and juveniles. This is in contrast to the five segments present in other species of the S. paraneptunus complex. [1]

Their specific name is derived from their affinity to the Synalpheus paraneptunus complex and the fact that they are the smallest member of the group in terms of body size. [1]

Description

Synalpheus microneptunus are small shrimp, with a carapace length of only 2.2 to 2.9 mm (0.087 to 0.114 in). The carapace is smooth with sparsely distributed bristles (setae). The posterior end of which has a distinct cardiac notch. The anterior spine of the carapace (rostrum) is flanked by two slightly shorter and stouter blunt spines (the ocular hoods) directly covering the eyestalks. [1]

The body is more or less cylindrical in shape. The major first pereopod (the snapping claw) is very large, with the palm (carpus) more than twice as long as the fingers. The carpus has a small triangular spine on the outer and upper end, curving towards the movable finger (dactyl). The fixed finger is slightly shorter than the dactyl. The palm of the minor first pereopod (the feeding claw) is less than twice as long as it is wide, with the fingers shorter than the carpus. The dactyl is blade-like in shape with three teeth near the tip. The fixed finger is trowel-like in shape with a single tooth near the tip. The second to fifth pair of pereopods (the walking legs) are slender, progressively growing weaker towards the fifth pair. The second pair is distinctive for having four segments on the carpus. [1]

The telson has two groups of two spines on the outer edges of the posterior end. In between them are six bristles (setae). On the dorsal surface of the telson are two pairs of large spines situated far from the lateral edges, and separated from each other by 35% to 50% of the width of the telson. The exopods of the uropods each have three teeth on the outer posterior margins, with a movable spine in between them, roughly in line with the central tooth. [1]

In life, Synalpheus microneptunus have pale nondescript coloration, with their extremities tipped by dull yellow-orange. The ovaries and embryos in breeding females are green. [1]

Ecology

Like most members of the genus Synalpheus found in the western Atlantic, Synalpheus microneptunus are exclusively associated with sponges. They are cryptofaunal, being rarely seen by humans despite their relative abundance because they spend almost their entire lives within the complex network of tunnels of their host sponges, feeding on sponge tissue. [2]

Synalpheus microneptunus is one of at least seven known species of eusocial shrimp. The only known marine animals to exhibit eusociality. [2] Synalpheus microneptunus are only found in the sponges Neopetrosia proxima and Neopetrosia subtriangularis , forming small colonies averaging at six individuals, with a maximum of fifteen individuals. The colonies usually have a single breeding female (the queen). The rest of the individuals in the colony (all of them close kin) are non-ovigerous "defenders", who cooperatively defend the queen and their nest from invaders (usually conspecifics or congeners). Like other alpheid shrimps, they use specialized enlarged claws that when snapped can produce jets of water capable of stunning small animals. [1] [2]

Distribution

Synalpheus microneptunus is only known from the waters off the island of Barbados. In addition to the type locality, the Cement Factory Reef, additional individuals were also recovered from Brandon's beach, Breach Reef, and Spawnee Reef (all of which are off the western coast of the island). [1]

Related Research Articles

Decapod anatomy Entire structure of a decapod crustacean

The decapod crustacean, such as a crab, lobster, shrimp or prawn, 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:

Rhynchocinetidae Family of crustaceans

The family Rhynchocinetidae are a group of small, reclusive red-and-white shrimp. This family typically has an upward-hinged foldable rostrum, hence its taxon name Rhynchocinetidae, which means movable beak; this gives these shrimps their common name of hinge-beak shrimps. The family contains only two genera, Cinetorhynchus and Rhynchocinetes.

Alpheidae Family of crustacean

Alpheidae is a family of caridean snapping shrimp, characterized by having asymmetrical claws, the larger of which is typically capable of producing a loud snapping sound. Other common names for animals in the group are pistol shrimp or alpheid shrimp.

Sociality Form of collective animal behaviour

Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies.

<i>Synalpheus</i> Genus of crustaceans

Synalpheus is a genus of snapping shrimp of the family Alpheidae, presently containing more than 100 species; new ones are described on a regular basis, and the exact number even of described species is disputed.

<i>Acanthacaris</i> Genus of lobsters

Acanthacaris is a genus of deep-water lobsters. It contains two species, A. caeca and A. tenuimana, and is the only genus in the subfamily Neophoberinae.

Eusociality Highest level of animal sociality a species can attain

Eusociality, the highest level of organization of sociality, is defined by the following characteristics: cooperative brood care, overlapping generations within a colony of adults, and a division of labor into reproductive and non-reproductive groups. The division of labor creates specialized behavioral groups within an animal society which are sometimes referred to as 'castes'. Eusociality is distinguished from all other social systems because individuals of at least one caste usually lose the ability to perform at least one behavior characteristic of individuals in another caste.

<i>Pseudosquilla ciliata</i> Species of crustacean

Pseudosquilla ciliata, the common mantis shrimp, is a species of mantis shrimp, known by common names including rainbow mantis shrimp and false mantis shrimp. It is widespread in the tropical Indo-Pacific region and in both the western and eastern Atlantic Ocean.

Synalpheus carpenteri is a species of sponge-dwelling snapping shrimp described in 2006 from specimens collected from the Belizean Barrier Reef of the Exuma Islands, Bahamas, and the Atlantic coast of Panama. Its most identifying characteristic is the faint to bright orange overall color of the body. The species is named in honor of Michael Carpenter, Caribbean Coral Reef Ecosystem program, National Museum of Natural History, Smithsonian Institution, Washington, D.C.

<i>Pandalus montagui</i> Species of crustacean

Pandalus montagui is a species of cold-water shrimp in the family Pandalidae. It is the type species of the genus Pandalus and is variously known as the pink shrimp, Aesop shrimp and Aesop prawn.

Synalpheus regalis is a species of snapping shrimp that commonly live in sponges in the coral reefs along the tropical West Atlantic. They form a prominent component of the diverse marine cryptofauna of the region. For the span of their entire lives, they live in the internal canals of the host sponge, using it as a food resource and shelter. It has been shown that colonies contain over 300 individuals, but only one reproductive female. Also, larger colony members, most of which apparently never breed, defend the colony against heterospecific intruders. This evidence points towards the first known case of eusociality in a marine animal.

<i>Alpheus heterochaelis</i> Species of crustacean

Alpheus heterochaelis, the bigclaw snapping shrimp, is a snapper or pistol shrimp in the family Alpheidae. It is found in the western Atlantic Ocean and the Gulf of Mexico.

Procaris hawaiana is a species of shrimp in the family Procarididae, from Maui, Hawaii. The species is very similar to Procaris ascensionis from Ascension Island. In P. ascensionis the integument is less firm, the rostrum is shorter, the cervical groove is more distinct, and the third abdominal somite reaches less far posteriorly over the fourth; also the scaphocerite has the final tooth still less distinct than in P. hawaiana, and the last segment of its antennal peduncle is less slender.

Palaemonella burnsi is a species of shrimp in the family Palaemonidae, from Maui, Hawaii. This species is closest to Palaemonella lata, which it resembles in the broad scaphocerite in which the lamella overreaches the final tooth, and in the unarmed merus of the second pereiopods. It differs from P. lata in the much longer fused part of the two branches of the upper antennular flagellum, in the relatively much longer fingers and shorter palm of the second legs, in the unarmed carpus of the second legs. It is named after John A. Burns, Governor of Hawaii, for declaring the Ahiki Kinau area a nature reserve.

Periclimenes pholeter, is a species of shrimp belonging to the family Palaemonidae. The species is closest to Periclimenes indicus, P. obscurus and P. toloensis, resembling these species in the presence of an epigastric tooth on the carapace, the shape of the abdomen, the spinulation of the carapace, and the unarmed fingers of the first chelipeds. P. pholeter most resembles P. indicus by the elongatecarpus and long fingers of the second pereiopods, differing in these features from P. toloensis, which has the fingers slightly less than half as long as the palm. In P. obscurus the fingers are shorter than the palm, but the carpus is about as long as the palm. From P. indicus, this species differs: by the greater size; by the much higher rostrum and the greater number of ventral rostral teeth; by the shorter eye; by the less slender antennular peduncle; by the more deeply cleft upper antennular flagellum; by the more robust scaphocerite; by the fingers of the first pereiopods ; by the more slender pereiopods, especially the fifth, which is much longer than the ischium.

<i>Neopetrosia proxima</i> Species of sponge

Neopetrosia proxima is a species of marine petrosiid sponge native to the tropical and subtropical waters of the western Atlantic Ocean.

Neopetrosia subtriangularis is a species of marine petrosiid sponges native to the waters off Florida and the Caribbean Sea. They superficially resemble staghorn corals.

Alpheus tricolor is a crustacean belonging to the family of snapping shrimp. It was first isolated in Indonesia and Sri Lanka. It counts with a setose carapace, an acute rostrum, shallow adrostral furrows and a basicerite with a strong ventrolateral tooth. The lamella of its scaphocerite is not reduced, with an anterior margin that is concave. Its third maxilliped counts with an epipodial plate bearing thick setae, while its first chelipeds are found with their merus bearing a strong disto-mesial tooth; its third pereiopod has an armed ischium, with a simple and conical dactylus. Its telson is broad, distally tapering, with 2 pairs of dorsal spines. The species is named after its characteristic colour pattern, including white, red and orange.

<i>Alpheus fasqueli</i> Species of crustacean

Alpheus fasqueli is a crustacean belonging to the family of snapping shrimp. It was first isolated in Sri Lanka. It counts with a setose carapace, an acute and carinate rostrum, and unarmed orbital hoods. Its basicerite has a strong ventrolateral tooth. The lamella of its scaphocerite is not reduced. Its third maxilliped counts with an epipodial plate bearing thick setae, while its first chelipeds are found with their merus bearing a strong disto-mesial tooth; its third pereiopod has an armed ischium, with a simple and conical dactylus. Its telson is broad, distally tapering, with 2 pairs of dorsal spines. The species is named after Frédéric Fasquel, a photographer who contributed rare shrimp specimens for the Muséum national d'histoire naturelle.

<i>Synalpheus pinkfloydi</i> Species of snapping shrimp, named after Pink Floyd

Synalpheus pinkfloydi, the Pink Floyd pistol shrimp, is a species of snapping shrimp in the genus Synalpheus. Described in 2017, it was named after the rock band Pink Floyd, in part because it has a distinctive "bright pink-red claw". The sound it makes by snapping the claw shut reaches 210 decibels, and can kill nearby small fish.

References

  1. 1 2 3 4 5 6 7 8 9 Kristin M. Hultgren; Kenneth S. MacDonald III & J. Emmett Duffy (2011). "Sponge-dwelling snapping shrimps (Alpheidae: Synalpheus) of Barbados, West Indies, with a description of a new eusocial species" (PDF). Zootaxa . 2834: 1–16.
  2. 1 2 3 J. Emmett Duffy; Kenneth S. Macdonald III; Kristin M. Hultgren; Tin Chi Solomon Chak; Dustin R. Rubenstein (2013). "Decline and Local Extinction of Caribbean Eusocial Shrimp". PLOS ONE . 8 (2): e54637. doi:10.1371/journal.pone.0054637. PMC   3572134 . PMID   23418429.