The gulf ghost crab, ''Hoplocypode occidentalis'', is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

ghost crab Ghost crabs are semiterrestrial crabs of the subfamily (biology), subfamily Ocypodinae. They are common shore crabs in tropical and subtropical regions throughout the world, inhabiting deep burrows in the intertidal zone. They are generalist spec ...

s native to the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

coast of the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

, from the

Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja Ca ...

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

. It is the only species in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Hoplocypode''. Gulf ghost crabs are medium-sized, reaching a maximum overall body diameter of . They are one of only two ghost crab species found in the eastern Pacific (the other being the painted ghost crabs). However, gulf ghost crabs can easily be distinguished from painted ghost crabs by the absence of "horns" on their eyes.

Taxonomy

''Hoplocypode occidentalis'' was first described by the American marine biologist

William Stimpson William Stimpson (February 14, 1832 – May 26, 1872) was a noted American scientist. He was interested particularly in marine biology. Stimpson became an important early contributor to the work of the Smithsonian Institution and later, direc ...

in 1860 as ''Ocypoda occidentalis''. The

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

s were originally collected from

Cabo San Lucas Cabo San Lucas (, "Saint Luke Cape"), or simply just Cabo, is a resort city at the southern tip of the Baja California Peninsula, in the Mexican state of Baja California Sur. As at the 2020 Census, the population of the city was 202,694 inhabitan ...

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. It was transferred to its own genus ''Hoplocypode'' in 2013 by Katsushi Sakai and Michael Türkay based on the differences of their

gonopod Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millip ...

s (appendages modified into copulatory organs) from that of the rest of the members of the genus ''

Ocypode ''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 female ...

''. It is classified under the ghost crab

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Ocypodinae Ghost crabs are semiterrestrial crabs of the subfamily Ocypodinae. They are common shore crabs in tropical and subtropical regions throughout the world, inhabiting deep burrows in the intertidal zone. They are generalist scavengers and preda ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Ocypodidae The Ocypodidae are a family of semiterrestrial crabs that includes the ghost crabs and fiddler crabs. They are found on tropical and temperate shorelines around the world. Some genera previously included in the family are now treated as members o ...

. The specific name is from

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

'' occidentalis'' ("western"). They are commonly known as the "gulf ghost crab" in

English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...

and ''cangrejo de playa'' in

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Cana ...

Description

Gulf ghost crabs are medium-sized ghost crabs with deep bodies, reaching a maximum overall body diameter of . The upper surface of the body is generally dark gray with lighter colored marbling. The underside of the body, the tips of the walking legs, and the claws are creamy white. Their coloration varies, usually matching the color of the sand surrounding them, but they are easier to see on black volcanic sand and on light-colored dry sand. Hoplocypode leg

The carapace is squarish in shape and wider than it is long, with a length around and a width of . It is thickly covered with rough, small bumps (tubercles). Their eyestalks are large and elongated, but do not possess "horns" as in some other ghost crab species. The outer half of margins of the eye sockets curve distinctly inwards, with the outer edges (exorbital angles) triangular in shape with a sharp, forward-facing, pointed end. Like other ghost crabs, one of the claw appendages (

cheliped A chela ()also called a claw, nipper, or pinceris a pincer-like organ at the end of certain limbs of some arthropods. The name comes from Ancient Greek , through New Latin '. The plural form is chelae. Legs bearing a chela are called chelipeds. ...

s, the first

pereiopod The decapod (crustaceans 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 g ...

pair) of gulf ghost crabs is much bigger than the other. The palm of the larger cheliped is elongated with a serrated lower edge and covered with tubercles on the upper surface. It features

stridulating Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mech ...

(sound-producing) ridges on the inner surface of the palm, which is important for identifying different species within the subfamily Ocypodinae. In gulf ghost crabs, the stridulating ridge is short and composed of a row of 21 to 22 tubercles. The smaller cheliped tapers towards a pointed end. The second pair of walking legs are not more than two and a half times the length of the carapace. The fourth pair is relatively smaller and weaker in comparison to the other three pairs, reaching only to the middle of the propodus of the third pair. The mera and

carpi Carpi may refer to: Places * Carpi, Emilia-Romagna, a large town in the province of Modena, central Italy * Carpi (Africa), a city and former diocese of Roman Africa, now a Latin Catholic titular bishopric People * Carpi (people), an ancie ...

of all the legs are naked, but the propodi possess fur-like bristles (setae) on for the first three walking leg pairs varying by sex. In males, the propodi of the first and second pair of walking legs have their upper forward surfaces covered with setae. The propodi of the third pair of walking legs only have setae on the upper margin of the propodi. In females, the propodi of the third and last pair of walking legs do not possess bristles on the upper surfaces of their propodi. The first gonopods (modified copulatory organs) of males are also distinctively complex in shape, with a triangular cross-section at the base and becoming hoof-like towards the end. This characteristic is one of the diagnostic criteria for the genus. The covering (operculum) of the genital duct of the females has four sides and is membranous and slightly calcified. The genital slit is narrow and aligned along the middle of the operculum.

Ecology

Gulf ghost crabs live in burrows near the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

of open sandy beaches and on sand and silt banks near where river mouths empty into the sea. Larger individuals usually have burrows further up the shore, while smaller individuals are closer to the waves. They are

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

, emerging from their burrows just after sunset. They are fast-moving

generalist A generalist is a person with a wide array of knowledge on a variety of subjects, useful or not. It may also refer to: Occupations * a physician who provides general health care, as opposed to a medical specialist; see also: ** General pract ...

scavenger Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...

s and

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

s, usually feeding on decaying bodies of

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

and other

crustacea Crustaceans (Crustacea, ) 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 gro ...

ns. They are also devastating predators of eggs and hatchlings of sea turtles, including the olive Ridley sea turtle (''

Lepidochelys olivacea The olive ridley sea turtle (''Lepidochelys olivacea''), also known Common name, commonly as the Pacific ridley sea turtle, is a species of turtle in the Family (biology), family Cheloniidae. The species is the second-smallest and most abundant ...

'') and the leatherback sea turtle (''

Dermochelys coriacea The leatherback sea turtle (''Dermochelys coriacea''), sometimes called the lute turtle or leathery turtle or simply the luth, is the largest of all living turtles and the heaviest non-crocodilian reptile, reaching lengths of up to and weights ...

''). In

Playa Grande, Costa Rica Playa Grande, also known as Salinas, is a beach community on the Pacific coast of Costa Rica just north of Tamarindo. Parque Nacional Marino Las Baulas (Las Baulas Marine National Park) is found in Playa Grande. Las Baulas Marine National Park ...

, they've been observed to be responsible for as much as 48% of the total number of deaths in freshly hatched sea turtles crossing the beaches towards the water.

Distribution

Gulf ghost crabs are native to the eastern

coast of the Americas, from the

. They are

sympatric In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sh ...

with the painted ghost crab (''

Ocypode gaudichaudii ''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-E ...

''), and juvenile specimens of the two smaller than are very difficult to tell apart. However, the adults are readily distinguishable, as painted ghost crabs are brightly colored and possess "horns" (styles) on their eyestalks which are absent in gulf ghost crabs. Painted ghost crabs also prefer sheltered rocky beaches, while gulf coast crabs are found on open sandy beaches. Gulf ghost crabs also superficially resemble the Atlantic ghost crab (''

Ocypode quadrata The Atlantic ghost crab, ''Ocypode quadrata'', is a species of ghost crab. It is a common species along the Atlantic coast of the United States, where it is the only species of ghost crab; its range of distribution extends from its northernmost re ...

''), but the two species do not occur in the same areas, with the latter being only found in the western

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

coast of the Americas.

References

External links