Hemigrapsus estellinensis
Encyclopedia
Hemigrapsus estellinensis is a 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. H. estellinensis is closely related to species from the Pacific Ocean
such as Hemigrapsus oregonensis, but lived 500 mi (804.7 km) 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.
The chief difference between H. estellinensis and other species in the genus is the extensive pattern of rust-red spots on the animal's "drab green" carapace
. H. estellinensis also has a pair of conspicuous white spots near the ends of the H–shaped indentation on the animal's back, and another spot between each of those spots and the lateral margin of the carapace. The legs are marked with larger spots than the carapace, and both the chelipeds and the walking legs are shorter than in other species. There are no spots on the animal's underside, including the abdomen
. In males, the chelipeds bear a hairy patch containing chemoreceptors on the ventral side of the claw
.
Creel collected 6 males and ten females; one of the males is the holotype
and all the others are paratype
s. All sixteen are held in the National Museum of Natural History
as specimens USNM 107855 and USNM 107856. A few living specimens were taken to Wayland College (now Wayland Baptist University
), but died within 17 hours for unknown reasons. Two of the females laid eggs before dying, one laying 3,000 and the other 8,000.
in Hall County, Texas, 500 miles (804.7 km) from the nearest ocean. Before its extinction, it was the only troglobitic
crab in the contiguous United States
. Its occurrence so far from the ocean has been described as "curious", and the species was "probably a Pleistocene
relic
".
The springs originally produced water with a salinity
of 43‰ that fed the Prairie Dog Town Fork
of the Red River. The salinity derives from Permian
red beds
, and has a strong structuring effect on the Red River's biota. It had a flow of approximately 3000 gallons (11,356.2 l) per minute, and the pool was 65 ft (19.8 m) wide at the surface, which was at an altitude of 1742.5 feet (531.1 m) above sea level. At a depth of 25 ft (8 m), it was only 20 ft (6 m) wide, and then widened slightly down to a depth of 120 ft (37 m). Below that, an opening 3 ft (0.9144 m) wide led into a cavern completely filled with water.
The United States Army Corps of Engineers
built a dike around the Estelline Salt Springs in January 1964, which has reduced the chloride
load on the Red River by 240 tonnes (529,109.4 lb) per day. Before it was contained, the spring had a rich biota, comprising the cyanobacteria Oscillatoria
and Lyngbya
, the green algae
Ulva clathrata and U. intestinalis
, twenty species of diatom
, many invertebrate
s – including a species of barnacle
– and a single fish species, Cyprinodon rubrofluviatilis
. The springs have since increased in salinity, and many species have been driven to extinction
, including H. estellinensis and the undescribed barnacle. As early as December 1962, attempts to find further living individuals of H. estellinensis were unsuccessful, and it was probably extinct before Creel's description was published in 1964.
The closest relative of H. estellinensis is the shore crab Hemigrapsus oregonensis, which lives along the coast of the Pacific Ocean
. The entire genus is restricted to the Pacific Ocean, except for Hemigrapsus affinis which lives along the Atlantic coasts of South America, from Cape San Roque (Rio Grande do Norte
state, Brazil
) to the Gulf of San Matias (Patagonia
, Argentina
), and a population of Hemigrapsus sanguineus which has been introduced to New Jersey
from its native range in East Asia
, and now ranges from Portland, Maine
to North Carolina
.
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
, formerly endemic to the Texas Panhandle
Texas Panhandle
The Texas Panhandle is a region of the U.S. state of Texas consisting of the northernmost 26 counties in the state. The panhandle is a rectangular area bordered by New Mexico to the west and Oklahoma to the north and east...
. 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. H. estellinensis is closely related to species from the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
such as Hemigrapsus oregonensis, but lived 500 mi (804.7 km) 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.
Description
H. estellinensis has a rectangular carapace with almost parallel sides. Males have a carapace length of up to 18.5 millimetre (0.728346456692913 in) and a carapace width of up to 22 mm (0.866141732283465 in), while females have a carapace up to 17 mm (0.669291338582677 in) long and 22 mm (0.866141732283465 in) wide. The front corners of the carapace are developed into three strong teeth on each side.The chief difference between H. estellinensis and other species in the genus is the extensive pattern of rust-red spots on the animal's "drab green" carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
. H. estellinensis also has a pair of conspicuous white spots near the ends of the H–shaped indentation on the animal's back, and another spot between each of those spots and the lateral margin of the carapace. The legs are marked with larger spots than the carapace, and both the chelipeds and the walking legs are shorter than in other species. There are no spots on the animal's underside, including the abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
. In males, the chelipeds bear a hairy patch containing chemoreceptors on the ventral side of the claw
Chela (organ)
A chela is a pincer-like organ terminating certain limbs of some arthropods. The name comes from Greek through New Latin . The plural form is chelae. Legs bearing a chela are called chelipeds. Another name is claw because most chelae are curved and have a sharp point like a claw....
.
Creel collected 6 males and ten females; one of the males is the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
and all the others are paratype
Paratype
Paratype is a technical term used in the scientific naming of species and other taxa of organisms. The exact meaning of the term paratype when it is used in zoology is not the same as the meaning when it is used in botany...
s. All sixteen are held in the National Museum of Natural History
National Museum of Natural History
The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. Admission is free and the museum is open 364 days a year....
as specimens USNM 107855 and USNM 107856. A few living specimens were taken to Wayland College (now Wayland Baptist University
Wayland Baptist University
Wayland Baptist University is private, coeducational Baptist university based in Plainview, Texas, U.S.A. Wayland Baptist has a total of fourteen campuses in four additional Texas cities, five other states, and the country of Kenya. On August 31, 1908, the university was chartered by the state of...
), but died within 17 hours for unknown reasons. Two of the females laid eggs before dying, one laying 3,000 and the other 8,000.
Distribution and ecology
H. estellinensis lived in Estelline Salt Springs east of the town of EstellineEstelline, Texas
Estelline is a town in Hall County, Texas, United States. The population was 168 at the 2000 census. A July 1, 2008 U.S. Census Bureau estimate placed the population at 155.-Geography:...
in Hall County, Texas, 500 miles (804.7 km) from the nearest ocean. Before its extinction, it was the only troglobitic
Troglobite
Troglobites are small cave-dwelling animals that have adapted to their dark surroundings. Troglobite species include spiders, insects, fish and others. They live permanently underground and cannot survive outside the cave environment. Troglobite adaptations and characteristics include a heightened...
crab in the contiguous United States
Contiguous United States
The contiguous United States are the 48 U.S. states on the continent of North America that are south of Canada and north of Mexico, plus the District of Columbia....
. Its occurrence so far from the ocean has been described as "curious", and the species was "probably a Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
relic
Relict
A relict is a surviving remnant of a natural phenomenon.* In biology a relict is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas....
".
The springs originally produced water with a salinity
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
of 43‰ that fed the Prairie Dog Town Fork
Prairie Dog Town Fork Red River
Prairie Dog Town Fork Red River is a sandy-braided stream about long, formed at the confluence of Palo Duro Creek and Tierra Blanca Creek, about northeast of Canyon in Randall County, Texas, and flowing east-southeastward to the Red River about east of the 100th meridian, south-southwest of...
of the Red River. The salinity derives from Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
red beds
Red beds
Red beds are sedimentary rocks, which typically consist of sandstone, siltstone, and shale that are predominantly red in color due to the presence of ferric oxides. Frequently, these red-colored sedimentary strata locally contain thin beds of conglomerate, marl, limestone, or some combination of...
, and has a strong structuring effect on the Red River's biota. It had a flow of approximately 3000 gallons (11,356.2 l) per minute, and the pool was 65 ft (19.8 m) wide at the surface, which was at an altitude of 1742.5 feet (531.1 m) above sea level. At a depth of 25 ft (8 m), it was only 20 ft (6 m) wide, and then widened slightly down to a depth of 120 ft (37 m). Below that, an opening 3 ft (0.9144 m) wide led into a cavern completely filled with water.
The United States Army Corps of Engineers
United States Army Corps of Engineers
The United States Army Corps of Engineers is a federal agency and a major Army command made up of some 38,000 civilian and military personnel, making it the world's largest public engineering, design and construction management agency...
built a dike around the Estelline Salt Springs in January 1964, which has reduced the chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
load on the Red River by 240 tonnes (529,109.4 lb) per day. Before it was contained, the spring had a rich biota, comprising the cyanobacteria Oscillatoria
Oscillatoria
Oscillatoria is a genus of filamentous cyanobacterium which is named for the oscillation in its movement. Filaments in the colonies can slide back and forth against each other until the whole mass is reoriented to its light source. It is commonly found in watering-troughs waters, and is mainly...
and Lyngbya
Lyngbya
Lyngbya is a genus of cyanobacteria, unicellular autotrophs that form the basis of the oceanic food chain.Lyngbya form long unbranching filaments inside a rigid mucilage sheath. Sheaths may form tangles or mats, intermixed with other phytoplankton species...
, the green algae
Green algae
The green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic...
Ulva clathrata and U. intestinalis
Ulva intestinalis
Ulva intestinalis is a green alga in the division Chlorophyta, of the genus Ulva, also known by the common names gutweed and grass kelp. Until they were reclassified by genetic work completed in the early 2000s, the tubular members of the genus Ulva were in the genus Enteromorpha.-References:...
, twenty species of diatom
Diatom
Diatoms are a major group of algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons , fans , zigzags , or stellate colonies . Diatoms are producers within the food chain...
, many invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s – including a species of barnacle
Barnacle
A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have...
– and a single fish species, Cyprinodon rubrofluviatilis
Cyprinodon rubrofluviatilis
Cyprinodon rubrofluviatilis, known as the Red River pupfish, is a species of killifish from the United States. It is found only in the Red River and Brazos River drainages of Texas and Oklahoma. The specific epithet refers to the Red River. It grows to a total length of and feeds on midge larvae...
. The springs have since increased in salinity, and many species have been driven to extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
, including H. estellinensis and the undescribed barnacle. As early as December 1962, attempts to find further living individuals of H. estellinensis were unsuccessful, and it was probably extinct before Creel's description was published in 1964.
The closest relative of H. estellinensis is the shore crab Hemigrapsus oregonensis, which lives along the coast of the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. The entire genus is restricted to the Pacific Ocean, except for Hemigrapsus affinis which lives along the Atlantic coasts of South America, from Cape San Roque (Rio Grande do Norte
Rio Grande do Norte
Rio Grande do Norte is one of the states of Brazil, located in the northeastern region of the country, occupying the northeasternmost tip of the South American continent. Because of its geographic position, Rio Grande do Norte has a strategic importance. The capital and largest city is Natal...
state, Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
) to the Gulf of San Matias (Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
, Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
), and a population of Hemigrapsus sanguineus which has been introduced to New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
from its native range in East Asia
East Asia
East Asia or Eastern Asia is a subregion of Asia that can be defined in either geographical or cultural terms...
, and now ranges from Portland, Maine
Portland, Maine
Portland is the largest city in Maine and is the county seat of Cumberland County. The 2010 city population was 66,194, growing 3 percent since the census of 2000...
to North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
.
External links
- Estelline Salt Springs: 34°32′51"N 100°25′20"W