| Emerita rathbunae | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Anomura |
| Family: | Hippidae |
| Genus: | Emerita |
| Species: | E. rathbunae |
| Binomial name | |
| Emerita rathbunae Schmitt, 1935 | |
Emerita rathbunae is a species of "mole crabs" or "sand crabs" in the genus Emerita that lives along the tropical Pacific coasts of the Americas.
Emerita rathbunae exhibits an extreme form of sexual dimorphism, with tiny neotenous males attaching themselves to the female's appendages, "thus carrying the tendency for small males in this genus almost to the verge of parasitism". [1] Sexually mature females are typically 33–44 mm (1.3–1.7 in) in carapace length, while males are only 2.5–3.0 mm (0.10–0.12 in). [2]
Emerita rathbunae is found on the shores of the eastern Pacific Ocean, from the southern end of the Gulf of California in Mexico to Iquique in northern Chile, including the Galápagos Islands. [3] In the south of its range, E. rathbunae co-occurs with the southern population of E. analoga , which occurs as far north as mainland Ecuador. [3]
Despite their sympatry, the closest relative of E. rathbunae is not E. analoga; rather, E. rathbunae is part of a clade that also includes species from the western Atlantic Ocean, including E. portoricensis and E. benedictii . [4] The last common ancestor of the genus is thought to have lived in the Pacific Ocean, and to have colonised the Gulf of Mexico when the Isthmus of Panama was submerged, and E. rathbunae is thought to have similarly recolonised the Pacific from ancestors that lived on the Atlantic side of the Isthmus of Panama. [4]
Emerita rathbunae was described by Waldo L. Schmitt in 1935; the type locality was Punta Chame in Panama, and the holotype was deposited in the United States National Museum as specimen USNM 47887. The specific epithet rathbunae commemorates the American carcinologist Mary J. Rathbun. [5]
Emerita rathbunae lives in the intertidal zone, where it uses the swash for transportation and filter-feeding. In Ecuador, it is one of the most abundant animals to surf the swash, [6] together with the sea snail Olivella semistriata . The two avoid competition since E. rathbunae prefers steeper beaches with coarser sediments and rougher swash than O. semistriata, and positions itself lower in the swash than O. semistriata. [6] Based on comparisons with other Emerita species, E. rathbunae is thought to be a very capable swimmer, and to burrow rapidly into the sand. [6]
The larvae of E. rathbunae pass through a variable number of moults before reaching adulthood. [7] While the majority of larvae pass through eight zoeal stages before reaching the megalopa, others may pass through seven or nine. This process lasts 64–96 days, during which time the larvae increase in length from around 1 mm (0.04 in) to around 8 mm (0.31 in). [7] They remain as megalopa larvae for 10–13 days, before moulting into the juvenile form. [7]
Emerita is a small genus of decapod crustaceans, known as sand crabs, or mole crabs. These small animals burrow in the sand in the swash zone and use their antennae for filter feeding.
Ovalipes ocellatus, known as the lady crab, is a species of crab from eastern North America. Other names for it include the leopard crab or Atlantic leopard crab due to the leopard-like rosette patterns on its shell, the calico crab, or ocellated crab. It has a shell 3 in (7.6 cm) long and only slightly wider, which is covered in clusters of purple spots. It occurs from Canada to Georgia, and lives mainly on molluscs, such as the Atlantic surf clam.
Mary Jane Rathbun was an American zoologist who specialized in crustaceans. She worked at the Smithsonian Institution from 1884 until her death. She described more than a thousand new species and subspecies and many higher taxa.
The Puerto Rican sand crab, Emerita portoricensis, is a species of "sand crab" belonging to the genus Emerita, which is native to the main island of Puerto Rico and its archipelago. This species has also been found on beaches off the coast of Venezuela. The most detailed study conducted on the species was done by Miguel P. Sastre between 1988 and 1992. This investigation determined that the species has diotic traits and that there are size and survival differences between sexes. Both sexes reach sexual maturity three months after birth.
Hippoidea is a superfamily of decapod crustaceans known as sand crabs or mole crabs.
Profilicollis is a genus of acanthocephalan parasites of crustaceans. The status of the genus Profilicollis has been debated, and species placed in this genus were formerly included in the genus Polymorphus. However, research on the morphology of the group and their use of hosts has concluded that Profilicollis and Polymorphus should be regarded as distinct genera, and species previously described as Polymorphus altmani are now referred to as Profilicollis altmani in taxonomic and biological literature. Profilicollis parasites infect decapod crustaceans, usually shore crabs, as intermediate hosts, and use many species of shorebirds as definitive (final) hosts.
Xantho poressa, the jaguar round crab, is a species of crab from the eastern Atlantic Ocean. It is one of four species in the genus Xantho.
Olivella semistriata is a species of small sea snail, a marine gastropod mollusk in the family Olividae, the olives. Species in the genus Olivella are commonly called dwarf olives With the very similar Olivella columellaris it forms the subgenus Pachyoliva. Both species are suspension feeders. They use unique appendages of the propodium to deploy mucus nets which capture suspended particles from the backwash on sandy beaches of the tropical eastern Pacific. Olivella semistriata is a swash-surfer; the snails use their expanded foot as an underwater sail to follow the tidal movement of the backwash zone in which they feed.
Ocypode gaudichaudii, also known as the painted ghost crab or cart driver crab, is a species of crab found on Pacific beaches from El Salvador to Chile as well as on the Galápagos Islands. The species was first described by Henri Milne-Edwards and Hippolyte Lucas in 1843.
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.
Pisidia longicornis, the long-clawed porcelain crab, is a species of porcelain crab that lives in the north-eastern Atlantic Ocean. It varies from reddish to white, and grows to a carapace width of 1 cm (0.4 in). It was first named by Carl Linnaeus in 1767, although the etymology remains unclear.
Guinotellus melvillensis is a species of crabs in the family Xanthidae, the only species in the genus Guinotellus. It is a benthic crab with an ovate carapace within the subfamily Euxanthinae.
Emerita analoga, the Pacific sand crab, Pacific mole crab or coldwater mole crab, is a species of small, sand-burrowing decapod crustacean found living in the sand along the temperate western coasts of North and South America. It is found on exposed sandy beaches in the swash region of the intertidal zone.
Dyspanopeus sayi is a species of mud crab that is native to the Atlantic coast of North America. It has also become established outside its native range, living in Swansea Docks since 1960, the Mediterranean Sea since the 1970s, the North Sea since 2007 and the Black Sea since 2010. It can reach a carapace width of 20 mm (0.8 in), and has black tips to its unequal claws. It feeds on bivalves and barnacles, and is in turn eaten by predators including the Atlantic blue crab, Callinectes sapidus. Eggs are produced from spring to autumn, the offspring reach sexual maturity the following summer, and individuals can live for up to two years. The closest relative of D. sayi is D. texanus, which lives in the Gulf of Mexico; the two species differ in subtle features of the genitalia and the last pair of walking legs.
Albunea carabus is a rare species of "sand crab" or "mole crab" in the genus Albunea. It lives in shallow, turbulent waters in sandy areas of the tropical eastern Atlantic Ocean and the Mediterranean Sea.
Brachynotus sexdentatus is a species of crab in the family Varunidae. It is native to the Mediterranean Sea and Black Sea, and became established for a time in Swansea Docks. It grows to a maximum carapace width of 18 mm (0.71 in), and lives in shallow water on muddy bottoms.
Pachyoliva is a subgenus of small sea snails, marine gastropod mollusks in the genus Olivella, the dwarf olives, within the family Olividae, the olives. Species in this subgenus inhabit soft sediments in the intertidal and subtidal zones of sandy beaches of the Panamic faunal province, that is, the west coast of the Americas from Baja California to north Peru.
Hippa adactyla is a species of small, sand-burrowing decapod crustacean found living along the coasts of Indo-West Pacific waters. It is found on exposed sandy beaches in the swash region of the intertidal zone.
Emerita talpoida, known generally as the Atlantic mole crab or Atlantic sand crab, is a species of mole crab in the family Hippidae. It is found in the western Atlantic Ocean and Mexico along the shoreline.
Leptuca leptodactyla, commonly known as the thin-fingered fiddler crab or the western Atlantic fiddler crab, is a species of fiddler crab native to the western Atlantic coast of the Americas.