''Lingula reevii'' is an inarticulated

brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...

species assigned to the family

Lingulidae ''Lingula'' is a genus of brachiopods within the class Lingulata. ''Lingula'' or forms very close in appearance have existed possibly since the Cambrian. Like its relatives, it has two unadorned organo-phosphatic valves and a long fleshy stalk. ' ...

. ''L. reevii'' is rare and is known to occur in shallow, sandy reef flats in Kaneohe Bay,

Oahu Oahu (, , sometimes written Oahu) is the third-largest and most populated island of the Hawaiian Islands and of the U.S. state of Hawaii. The state capital, Honolulu, is on Oahu's southeast coast. The island of Oahu and the uninhabited Northwe ...

, Hawaii, as well as in Japan, and Ambon, Indonesia.

Description

The shell is oblong oval, broadest in the middle, and rather narrow. The sides are very gently curved outwardly; the posterior edge tapers to a sharp point. The shell valves are moderately convex with a smooth surface. Color is blue-green or emerald and verdigris-green, especially along the middle. The lophophore consists of a fold of the body wall that possesses a crown of ciliated tentacles surrounding the mouth. The lateral

cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...

create a water current and fine

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

are transported down the tentacles to the brachial groove and into the mouth. It is ammonotelic.

Ecology

''L. reevii'' is a filter-feeding invertebrate that burrows vertically in sandy sediment, leaving a three-hole siphonal opening at the surface. When disturbed, a rapid contraction of the pedicle pulls the animal below the surface and the siphonal openings are reduced to a slit. This species is capable of upward burrowing through a sediment layer, even if the animal has to autotomize (detach) the pedicle.

Reproduction

''Lingula'' has separate sexes, and gametes are shed into the water column for external fertilization. Embryos develop into a free swimming larva that looks like a tiny adult; they develop a shell while planktonic. As additional shell material is laid down, the animal becomes heavy, sinks to the bottom, and takes up its adult existence. There is no metamorphosis in ''Lingula''. The lifespan of ''Lingula spp.'' is estimated to be 5 to 8 years.

Threats and conservation

The species has declined in density from 500 per square meter in the 1960s to a maximum of 4 per square meter. The main threats are: 1) habitat degradation and alteration; 2)

overexploitation Overexploitation, also called overharvesting or ecological overshoot, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to ...

; 3)

marine pollution Marine pollution occurs when substances used or spread by humans, such as industrial waste, industrial, agricultural pollution, agricultural, and municipal solid waste, residential waste; particle (ecology), particles; noise; excess carbon dioxi ...

and

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to th ...

; 4) a vulnerable life history; and 5) a limited distribution. ''Lingula reevii'' is a U.S. National Marine Fisheries Service Species of Concern. Species of Concern are those species about which the U.S. Government’s

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with Weather forecasting, forecasting weather, monitoring oceanic and atmospheric conditions, Hydrography, charting the seas, ...

, National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S.

Endangered Species Act The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...

.Endangered Species Act - Office of Protected Resources - NOAA Fisheries
/ref>

References

External links

University of California Museum of Paleontology {{DEFAULTSORT:Lingula Reevii Lingulata Invertebrates of Hawaii Animals described in 1880