| Geograpsus severnsi Temporal range: | |
|---|---|
 | |
| Holotype; scale bar is 10 mm | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Subphylum: | |
| Class: | |
| Order: | |
| Infraorder: | |
| Family: | |
| Genus: | |
| Species: | G. severnsi |
| Binomial name | |
| Geograpsus severnsi Paulay & Starmer, 2011 | |
Geograpsus severnsi is an extinct species of land crab from Hawaii. It died out shortly after humans colonized the Hawaiian Islands. It is the first known documented crab to become extinct after the ice age.
Specimens of G. severnsi have been recovered from several of the Hawaiian volcanic islands, including Hawaiʻi, Maui, Oʻahu and Kauaʻi. They have been found up to 2 km (1.2 mi) inland, and at altitudes of up to 950 m (3,120 ft). [1] Its range appears to have overlapped with that of the more coastal G. crinipes , a species which is widespread across the Indo-Pacific. [1]
Geograpsus severnsi was probably the largest species in the genus. Based on the size of sternites, its carapace width may have been up to 66 mm (2.6 in). [1] Its claws were 20–49 mm (0.8–1.9 in) long, and in all the specimens with both claws preserved, the right claw was larger than the left. [1] Most of the known specimens are males, but this is thought to reflect behavioral differences between the sexes, rather than an extreme sex ratio in the population. [1] This is also seen in the Ascension Island species Johngarthia lagostoma , where females are likely to die on their reproductive migration. It is therefore likely that G. severnsi had a similar ecology to other land crabs. [1] It would have been an omnivore and a predator, possibly feeding on insects, land snails and bird's eggs. [2] Outside the genus Geograpsus, there are no truly terrestrial crabs in Hawaii; the only well documented species is Chiromantes obtusifrons , which may move up to 50 m (160 ft) inland, at elevations up to 10 m (33 ft). [1]
G. severnsi is one of five species in the genus Geograpsus . Its closest relative appears to be G. grayi , a species found from the western Indian Ocean to the Line Islands and Marshall Islands. [1] G. severnsi has been known to Hawaiian zoologists since the mid-1970s, but was only formally described in 2011. [1] The specific epithet severnsi commemorates Mike Severns, the discoverer of the cave which housed most of the remains. [1]
The megamouth shark is a species of deepwater shark. It is rarely seen by humans and is the smallest of the three extant filter-feeding sharks alongside the relatively larger whale shark and basking shark. Since its discovery in 1976, fewer than 100 specimens have been observed or caught. Like the other two planktivorous sharks, it swims with its mouth wide open, filtering water for plankton and jellyfish. It is recognizable from its large head with rubbery lips. The megamouth is so unlike any other type of shark that it is usually considered to be the sole extant species in the family Megachasmidae, though some scientists have suggested it may belong in the family Cetorhinidae.
Spirula spirula is a species of deep-water squid-like cephalopod mollusk. It is the only extant member of the genus Spirula, the family Spirulidae, and the order Spirulida. Because of the shape of its internal shell, it is commonly known as the ram's horn squid or the little post horn squid. Because the live animal has a light-emitting organ, it is also sometimes known as the tail-light squid.
Newton's parakeet, also known as the Rodrigues parakeet or Rodrigues ring-necked parakeet, is an extinct species of parrot that was endemic to the Mascarene island of Rodrigues in the western Indian Ocean. Several of its features diverged from related species, indicating long-term isolation on Rodrigues and subsequent adaptation. The rose-ringed parakeet of the same genus is a close relative and probable ancestor. Newton's parakeet may itself have been ancestral to the endemic parakeets of nearby Mauritius and Réunion.
The Japanese spider crab is a species of marine crab that lives in the waters around Japan. It has the largest known leg-span of any arthropod. It goes through three main larval stages along with a prezoeal stage to grow to its great size.
Ocypode is a genus of ghost crabs found in the sandy shores of tropical and subtropical regions throughout the world. They have a box-like body, thick and elongated eyestalks, and one claw is larger than the other in both males and females. They inhabit deep burrows in the intertidal zone. They are primarily nocturnal, and are generalist scavengers and predators of small animals. The genus contains 21 species.
The Seychelles parakeet or Seychelles Island parrot is an extinct species of parrot that was endemic to the Seychelles in the Indian Ocean. It was scientifically named Palaeornis wardi by the British ornithologist Edward Newton in 1867, and the specific name honours the British civil commissioner Swinburne Ward who procured the specimens that formed the basis for the description. It was found on the islands of Mahé, Silhouette, and possibly Praslin. Ten skin specimens exist today, but no skeletons. Though it was later moved to the genus Psittacula, genetic studies have led some researchers to suggest it should belong in a reinstated Palaeornis along with the closely related Alexandrine parakeet of Asia.
Mesonyx is a genus of extinct mesonychid mesonychian mammal: fossils of the various species are found in Early to Late Eocene-age strata in the United States and Early Eocene-aged strata in China, 51.8—51.7 Ma (AEO).
The King Island emu is an extinct subspecies of emu that was endemic to King Island, in the Bass Strait between mainland Australia and Tasmania. Its closest relative may be the extinct Tasmanian emu, as they belonged to a single population until less than 14,000 years ago when Tasmania and King Island were still connected. The small size of the King Island emu may be an example of insular dwarfism. The King Island emu was the smallest of all known emus and had darker plumage than the mainland emu. It was black and brown and had naked blue skin on the neck, and its chicks were striped like those on the mainland. The subspecies was distinct from the likewise small and extinct Kangaroo Island emu in a number of osteological details, including size. The behaviour of the King Island emu probably did not differ much from that of the mainland emu. The birds gathered in flocks to forage and during breeding time. They fed on berries, grass and seaweed. They ran swiftly and could defend themselves by kicking. The nest was shallow and consisted of dead leaves and moss. Seven to nine eggs were laid, which were incubated by both parents.
Maiacetus is a genus of early middle Eocene cetacean from the Habib Rahi Formation of Pakistan.
Ectenosaurus is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Plioplatecarpinae subfamily alongside genera like Angolasaurus and Platecarpus. Ectenosaurus is known from the Santonian and Campanian of Kansas, Alabama, and Texas.
The coconut crab is a species of terrestrial hermit crab, also known as the robber crab or palm thief. It is the largest terrestrial arthropod in the world, with a weight of up to 4.1 kg (9 lb). It can grow to up to 1 m in width from the tip of one leg to the tip of another. It is found on islands across the Indian Ocean, and parts of the Pacific Ocean as far east as the Gambier Islands, Pitcairn Islands and Caroline Island, similar to the distribution of the coconut palm; it has been extirpated from most areas with a significant human population, including mainland Australia and Madagascar. Coconut crabs also live off the coast of Africa near Zanzibar.
Gecarcinus ruricola is a species of terrestrial crab. It is the most terrestrial of the Caribbean land crabs, and is found from western Cuba across the Antilles as far east as Barbados. Common names for G. ruricola include the purple land crab, black land crab, red land crab, and zombie crab.
Hemigrapsus estellinensis is an extinct species of crab, formerly endemic to the Texas Panhandle. It was discovered by Gordon C. Creel in 1962 and was probably already extinct before his description was published in 1964, after the Estelline Salt Springs where it lived were contained by the United States Army Corps of Engineers. H. estellinensis is closely related to species from the Pacific Ocean such as Hemigrapsus oregonensis, but lived 800 km (500 mi) inland in a hypersaline spring. It differed from its relatives by the pattern of spots on its back, and by the relative sizes of its limbs.
Johngarthia lagostoma is a species of terrestrial crab that lives on Ascension Island and three other islands in the South Atlantic. It grows to a carapace width of 110 mm (4.3 in) on Ascension Island, where it is the largest native land animal. It exists in two distinct colour morphs, one yellow and one purple, with few intermediates. The yellow morph dominates on Ascension Island, while the purple morph is more frequent on Rocas Atoll. The species differs from other Johngarthia species by the form of the third maxilliped.
Geograpsus is a genus of crabs in the family Grapsidae, containing four extant species, and one extinct species:
Seychellum alluaudi is a species of freshwater crab endemic to the Seychelles, and the only true freshwater crab in that country. It lives in rainforest streams on the archipelago's granitic high islands. Although it may be abundant, little is known about its biology. If its habitat were to decline in quality, S. alluaudi might become endangered, but it is currently listed as Vulnerable on the IUCN Red List.
The largest animal known ever to have lived is confirmed to be the blue whale. The maximum recorded weight was 190 tonnes for a specimen measuring 27.6 metres (91 ft), whereas longer ones, up to 33.6 metres (110 ft), have been recorded but not weighed. It is estimated however that this individual could have a mass of 250 tonnes. The title of the longest non-colonial animal is probably held by the lion's mane jellyfish.
Oregonia bifurca, commonly known as the split-nose crab or the split-nose decorator crab, is a species of crabs belonging to the family Oregoniidae. It is a rare deep-water species that inhabits the tops of seamounts and guyots in the northeastern Pacific Ocean; from the Aleutian Islands, the Bering Sea, the Hawaiian–Emperor seamount chain, to the waters off British Columbia. It is closely related to the more common shallow-water species Oregonia gracilis, the graceful decorator crab.
Ocypode brevicornis is a species of ghost crab native to the Indian Ocean, from the Gulf of Oman to the Nicobar Islands. They are relatively large ghost crabs with a somewhat trapezoidal body. The carapace reaches a length of 41 mm (1.6 in) and a width of 50 mm (2.0 in). They are a mottled brown to yellow in coloration. Like other ghost crabs, one of their claws is much larger than the other. Their eyestalks are large and elongated, tipped with prolongations at the tip known as styles. They are common inhabitants of open sandy beaches, living in burrows in the intertidal zone.
Geograpsus lividus is a species of crab in the family Grapsidae. Little research has been conducted on this species. It was originally classified as belonging to the genus Grapsus; however, this name is no longer used.
