''Procaris hawaiana'' is a species of

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

in the family Procarididae, from

Maui The island of Maui (; Hawaiian: ) is the second-largest of the islands of the state of Hawaii at 727.2 square miles (1,883 km2) and is the 17th largest island in the United States. Maui is the largest of Maui County's four islands, which ...

, Hawaii. The species is very similar to ''

Procaris ascensionis ''Procaris ascensionis'' is a species of shrimp, known only from two saltwater pools on Ascension Island Ascension Island is an isolated volcanic island, 7°56′ south of the Equator in the South Atlantic Ocean. It is about from the coast ...

'' from

Ascension Island Ascension Island is an isolated volcanic island, 7°56′ south of the Equator in the South Atlantic Ocean. It is about from the coast of Africa and from the coast of South America. It is governed as part of the British Overseas Territory o ...

. In ''P. ascensionis'' the

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind. Etymology The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or ...

is less firm, the

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...

is shorter, the cervical groove is more distinct, and the third abdominal

somite The somites (outdated term: primitive segments) are a set of bilaterally paired blocks of paraxial mesoderm that form in the embryonic stage of somitogenesis, along the head-to-tail axis in segmented animals. In vertebrates, somites subdivide in ...

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.

Description

The rostrum is short and pointed, it reaches just beyond the eyes. In lateral view it is slender, and tapers regularly towards the tip. In dorsal view it is elongate triangular and its lateral margins merge gradually with the orbital margin. The

carapace A carapace is a Dorsum (biology), dorsal (upper) 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 tor ...

bears no spines or carinae, only a narrow and shallow cervical groove is visible, which does not reach the dorsum. The abdominal somites are smooth. The first has the pleura large and rounded. The pleura of the second overlap both those of the first and third. The third somite is noticeable in that the posteromedian part is hood-like prolonged posteriorly and reaches beyond the middle of the fourth somite. The fourth somite has the pleura rounded, those of the fifth end in a bluntly rounded top. The sixth somite is approximately 1.5 times as long as the fifth, both its pleura and posterolateral angles are rounded. The

telson The telson () is the posterior-most division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on accou ...

is distinctly longer than the sixth abdominal somite. It is elongate triangular and has two pairs of dorsal spines. The posterior margin of the telson is broadly triangular with a blunt top. It bears 4 pairs of spines. Its eyes are broad and have at the inner half of their anterior margin a conical process which is directed forwards and upward and reaches beyond the eye itself. The rest of the eye is broadly and bluntly triangular in dorsal view and bears an irregular pigment spot. Like in ''P. ascensionis'', no distinct

cornea The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power ...

l elements are visible. The antennula has a large pointed stylocerite, which reaches about to the end of the second segment of the antennular peduncle. Two simple antennular flagella are present, both being very long. The scaphocerite is twice as long as wide. The

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...

consists of a single molar process, which is pointed and has a cutting edge which is dark coloured and shows a few small teeth; there is a distinct three-segmented

palp Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and ...

. The

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

has two

endite The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plur ...

s, the lower is oval to quadrangular, the upper is truncate and has the distal margin with strong spines; there is a single undivided palp. The three

maxilliped An appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body. In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including anten ...

s all have a well-developed

exopod The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plur ...

with a multi-articulated flagellum. The epipod is oval. The

dactylus The dactylus is the tip region of the tentacular club of cephalopods and of the leg of some crustaceans (see arthropod leg). In cephalopods, the dactylus is narrow and often characterized by the asymmetrical placement of suckers (i.e., the ve ...

is elongate and is attached with one of its longer sides to the propodus. Its

carpus In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carpal ...

is short and the merus more than twice as long as the carpus. The merus is somewhat shorter than the carpus and 3/5 of the length of the

ischium The ischium () form ...

. The latter is wider than any of the other segments and its posterodistal end reaches beyond the base of the merus. None of the legs shows a

chela Chela may refer to: * ''Chela'' (fish), a genus of small minnow-type fish in the Cyprinid family * Chela (organ), a pincer-like organ terminating certain limbs of some arthropods such as crabs * Chela (meteorite), a meteorite fall of 1988 in Tan ...

(claw). The ischium bears a large movable spine. The carapace lengths of ranges between , the total length between about . Maciolek (1974) described the species as the

exoskeleton An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the ...

having a slight red pigmentation, particularly along the midline; with some black pigment associated with its eyes. The species is a pale, slightly purplish pink shrimp with the carapace yellow or whitish by the presence of its internal organs shining through. The carapace has a darker red spot behind the rostrum, and a less distinct one near the middle of the posterior margin. The abdomen is pink with a transverse orange-red band over the first

tergite A ''tergum'' (Latin for "the back"; plural ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'mar ...

, and a narrow median longitudinal streak on the fourth somite. On its tail fan there are several red spots. The lower surface of the body is uniformly pink, the thorax being brighter than that of the abdomen. The appendages are pale pink or colourless. Other specimens have shown different colour patterns.

Distribution

''Procaris hawaiana'' has been seen in Cape Kinau, and

Hawaii Island Hawaii ( ; haw, Hawaii ) is the largest island in the United States, located in the state of Hawaii. It is the southeasternmost of the Hawaiian Islands, a chain of volcanic islands in the North Pacific Ocean. With an area of , it has 63% of t ...

, in small

anchialine pool An anchialine system (, from Greek ''ankhialos'', "near the sea") is a landlocked body of water with a subterranean connection to the ocean. Depending on its formation, these systems can exist in one of two primary forms: pools or caves. The primary ...

s, cohabitating with

Calliasmata ''Calliasmata'' is a genus of shrimp in the family Hippolytidae Hippolytidae is a family of cleaner shrimp, also known as broken-back shrimp or anemone shrimp. The term "broken-back shrimp" also applies to the genus ''Hippolyte'' in particul ...

species.

Behaviour

According to Maciolek (1974):Maciolek, John A., and Richard E. Brock. Aquatic survey of the Kona coast ponds, Hawaii Island. Vol. 74. No. 4. University of Hawaii Sea Grant Program, 1974. The animal swims with its legs extended fan-like and symmetrically in a plane below the body. Usually it does so close to the substrate (lava), occasionally in mid-water, and sometimes along the underside of the surface film.

References

External links

{{Taxonbar, from=Q14167421 Decapods Fauna of Hawaii Freshwater crustaceans of North America ESA endangered species Crustaceans described in 1973