| Pinna carnea | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Order: | Pteriida |
| Family: | Pinnidae |
| Genus: | Pinna |
| Species: | P. carnea |
| Binomial name | |
| Pinna carnea | |
| Synonyms [1] | |
Pinna carnea, commonly called the amber pen shell, is a species of bivalve mollusc in the family Pinnidae.
The amber pen shell has a pair of long, thin translucent valves held together by ligaments that run along the entire dorsal side of the bivalve. The bivalve is triangular with 8 to 12 low ribs radiating from the pointed anterior end (or umbo) to the large posterior edge. The exterior of the shell is usually a dull orange amber-like color and may have fragile, scale-like spines that often become eroded over time. The anterior end is usually buried and attached by byssal threads, whereas its wider posterior gaping end extends above the sea bottom surface to facilitate filter-feeding. Algae (e.g. Lobophora variegata ) and invertebrates such as sponges and encrusting corals tend to grow on the exposed part of the shell and may camouflage it very well.
The amber pen shell can be found in coastal western Atlantic waters, ranging from southern Florida across the Caribbean and the West Indies to Brazil. [2] [3] [4] [5]
The amber pen shell is benthic and usually occurs in medium to coarse sand or mixed substrata (sand, gravel, rocks), in fine calcareous sandy mud of eelgrass (e.g. Zostera spp.), in sandy substrata of turtle grass (e.g. Thalassia spp.) and other mixed-species seagrass meadows at depths usually between 2 and 15 metres (6 ft 7 in and 49 ft 3 in). [6] [7] [8]
The amber pen shell burrows as it grows, but the wide posterior end of the shell always remains exposed so water from above the seafloor can be drawn through the inhalent chamber of the mantle cavity. Typical of bivalves, water is drawn over gills or ctenidium by the beating of cilia where oxygen from the water is absorbed. Suspended food and other water-borne nutrients also become trapped in mucus, which is then transported to the mouth, digested and expelled as feces. Unique gutter-like waste canals in the viscera of the inhalent chamber also help to keep gills and other organs clear from silt and other unwanted water-borne particules by expelling these as pseudofeces. [6]
The amber pen shell may reach 30 cm (12 in) in length [6] with shell growth being extremely rapid after settlement [up to 2.2 mm (0.087 in) in length/day] and growth slowing down as shells get large and attain a refuge in size [at around 15 cm (5.9 in)]. [7] The exposed valves of amber penshells are subject to frequent damage as they often show breaks and scars. While its half-buried position facilitates filtering water from above silty bottoms, it also increases exposure to predators. Octopuses are likely important predators of amber pen shells. [9]
The amber pen shell is a hermaphrodite, the gonads producing both sperm and ova. The larvae are planktonic and drift with the currents. The shells of the planktonic larvae are transparent, pale golden or amber in color, and also triangular. Larvae likely settle anywhere they can attach byssal threads. [7] The larval shells are quickly eroded after settlement and byssal attachment, with few adult shells ever found with remains of their larval shell stage. [10] Amber pen shells are sessile and remain in the same spot for the rest of their lives, although dislodged individuals can re-establish themselves. [6]
The amber pen shell may host a number of symbionts in its mantle cavity. Shrimp Pontonia mexicana (Palaemonidae), cardinalfish Astrapogon stellatus, pea crabs (Pinnotheridae) and sea anemones (Actiniaria) have all been found sheltered inside its shell. [11]
Bivalvia, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. Bivalves as a group have no head and they lack some usual molluscan organs like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances.
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda.
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.
The Pteriomorphia comprise a subclass of saltwater clams, marine bivalve molluscs. It contains several major orders, including the Arcida, Ostreida, Pectinida, Limida, Mytilida, and Pteriida. It also contains some extinct and probably basal families, such as the Evyanidae, Colpomyidae, Bakevelliidae, Cassianellidae, and Lithiotidae.
The Pinnidae are a taxonomic family of large saltwater clams sometimes known as pen shells. They are marine bivalve molluscs in the order Pteriida.
Freshwater bivalves are one kind of freshwater mollusc, along with freshwater snails. They are bivalves which live in freshwater, as opposed to saltwater, the main habitat type for bivalves.
Perna perna, the brown mussel, is an economically important mussel, a bivalve mollusc belonging to the family Mytilidae. It is harvested as a food source but is also known to harbor toxins and cause damage to marine structures. It is native to the waters of Africa, Europe, and South America and was introduced in the waters of North America.
Pinna is a genus of bivalve molluscs belonging to the family Pinnidae. The type species of the genus is Pinna rudis.
Atrina rigida, commonly called the rigid pen shell, is a species of bivalve mollusc in the family Pinnidae.
Pinna nobilis, common name the noble pen shell or fan mussel, is a large species of Mediterranean clam, a marine bivalve mollusc in the family Pinnidae, the pen shells. It reaches up to 120 cm (4 ft) of shell length.
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda. The members are known as molluscs or mollusks. Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied.
Ostrea lurida, common name the Olympia oyster, after Olympia, Washington in the Puget Sound area, is a species of edible oyster, a marine bivalve mollusk in the family Ostreidae. This species occurs on the northern Pacific coast of North America. Over the years the role of this edible species of oyster has been partly displaced by the cultivation of non-native edible oyster species.
Pecten maximus, common names the great scallop, king scallop, St James shell or escallop, is a northeast Atlantic species of scallop, an edible saltwater clam, a marine bivalve mollusc in the family Pectinidae. This is the type species of the genus. This species may be conspecific with Pecten jacobaeus, the pilgrim's scallop, which has a much more restricted distribution.
Amygdalum papyrium, common name the Atlantic paper mussel, is a species of marine bivalve mollusc in the family Mytilidae, the true mussels. This species occurs along the Atlantic coast of North America, from Maryland to Florida, as well as in the Gulf of Mexico, from Texas to Mexico.
Pteria colymbus, the Atlantic winged oyster, is a species of bivalve mollusc in the family Pteriidae. It can be found along the Atlantic coast of North America, ranging from North Carolina to Bermuda and Brazil.
Atrina seminuda, the half-naked pen shell, is a species of bivalve mollusc in the family Pinnidae.
Codakia orbicularis, or the tiger lucine, is a species of bivalve mollusc in the family Lucinidae. It can be found along the Atlantic coast of North America, ranging from Florida to the West Indies.
Arca noae or the Noah's Ark shell is a species of bivalve mollusc in the family Arcidae. It is found in the Mediterranean Sea from low tide mark to a depth of 60 metres (200 ft).
Pinna rudis, the rough pen shell or spiny fan-mussel, is a species of bivalve mollusc in the family Pinnidae. It is the type species of the genus Pinna. Knowledge about this is sparse, with an absence of specific studies and literature.
Astrapogon stellatus is a species of ray-finned fish in the family Apogonidae, the cardinal fishes. It lives in the tropical western Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico. It is commonly known as the conchfish because it typically conceals itself in the mantle cavity of a living queen conch by day.