| Atrina zelandica | |
|---|---|
 | |
| A partly broken shell of Atrina zelandica | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Order: | Pteriida |
| Family: | Pinnidae |
| Genus: | Atrina |
| Species: | A. zelandica |
| Binomial name | |
| Atrina zelandica (Gray in Yate, 1835) [1] | |
Atrina zelandica, one of several species known as the horse mussel, is a large species of saltwater clam. It is found around New Zealand. [2]
The shell of Atrina zelandica is triangular, elongate and blackish, while the inside is pearly purple. [3] The valves are convex with rather close longitudinal ribs and semi-cylindrical hollow spines. [3] The body of Atrina zelandica is 280 mm long. [4] Atrina zelandica is the largest of all bivalve species in New Zealand, with some individuals of Atrina zelandica growing up to 400 mm in length. [5] Most individuals of Atrina Zelandica are between 30-260 mm long and 100-110 mm wide. [5]
The shell of Atrina zelandica has a crenellated posterior edge that extends a few centimeters above the substrate. [5] This helps keep the water intake clear of surface deposits but also provides a surface for various algae and invertebrates to attach to it, such as sponges and sea squirts. [6]
Atrina zelandica is native to New Zealand. [2] They inhabit depths of up to 50 m, primarily in muddy sand in the intertidal and subtidal zones in sheltered waters, and are widely distributed across the country. [5]
However, Atrina zelandica has experienced frequent die-offs in the Rangitoto Channel. Populations of 200-300 individuals per square meter have decreased to just 1-35 individuals per square meter over a period of 2-3 years. [5] [7] Possible explanations include damage caused by storms, shell damage leading to increased predation and over harvesting. [5] [7]
Atrina zelandica are classified as dioecious broadcast spawners. [5] Atrina zelandica spawns during the summer months but there is currently no available research on the age or sizes that Atrina zelandica begins breeding. [5] Atrina zelandcia grows rapidly during the first few years of life, sometimes up to 40 mm a year, but once shells exceed 166 mm long their growth slows significantly. [7] Individuals mature between 5 years and 15 years old. [7]
Atrina zelandica is a filter feeder and eats algae and bacteria. [2]
Atrina zelandica is parasitized by Pinnotheresnovae-zelandiae. [8] P. novae-zelandiae can cause significant problems for Atrina zelandica because they cause slow growth. [8]
The New Zealand pea crab, is a species of small, parasitic crab that lives most commonly inside New Zealand green-lipped mussels. Adult females are about the size and shape of a pea, while adult males are smaller and flatter. Adult New Zealand pea crabs are completely reliant on their host mussel for shelter and food, which it steals from the mussel's gills. The New Zealand pea crab is found throughout New Zealand and can infect up to 70% of natural populations. These crabs are of concern to green-lipped mussel aquaculture because they reduce the size and growth of mussels, although infected mussels can be harvested and consumed.
Tridacna gigas, the giant clam, is the most well-known species of the giant clam genus Tridacna. Giant clams are the largest living bivalve mollusks. Several other species of "giant clams" in the genus Tridacna, are often misidentified as Tridacna gigas.
The Veneridae or venerids, common name: Venus clams, are a very large family of minute to large, saltwater clams, marine bivalve molluscs. Over 500 living species of venerid bivalves are known, most of which are edible, and many of which are exploited as food sources.
Atrina fragilis, the fan mussel, is a species of large saltwater clam, a marine bivalve mollusc in the family Pinnidae, the pen shells.
Pecten novaezelandiae, common name the New Zealand scallop, is a bivalve mollusc of the family Pectinidae, the scallops. Its name is sometimes found misspelt as Pecten novaezealandiae.
Pinna is a genus of bivalve molluscs belonging to the family Pinnidae.
Atrina is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae.
Atrina rigida, commonly called the rigid pen shell, is a species of bivalve mollusc in the family Pinnidae.
Panopea zelandica, commonly known as the deepwater clam or New Zealand geoduck, is a large species of marine bivalve mollusc in the Panopea (geoduck) genus of the family Hiatellidae. It is also sometimes called a king clam, or a gaper – in reference to the shell not being closed at either end.
Talochlamys zelandiae, common name the fan shell, is a species of marine bivalve mollusc in the scallop family Pectinidae.
Euvola ziczac, or the zigzag scallop, is a species of bivalve mollusc in the family Pectinidae. It can be found along the Atlantic coast of North America, ranging from North Carolina to the West Indies and Bermuda.
Pinnotheres atrinicola is a small crab that lives symbiotically in the horse mussel Atrina zelandica around New Zealand. This species was recognised as being distinct from Pinnotheres novaezelandiae in 1983.
Haminoea is a genus of medium-sized sea snails or bubble snails, marine opisthobranch gastropod molluscs in the family Haminoeidae, the haminoea bubble snails, part of the clade Cephalaspidea, the headshield slugs and bubble snails.
Julia exquisita is a small species of sea snail in the family Juliidae.
Pinna carnea, commonly called the amber pen shell, is a species of bivalve mollusc in the family Pinnidae.
Coelotrochus tiaratus, whose common names include tiara top shell, brown top shell, mititi, and mitimiti is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.
Atrina pectinata is a species of bivalves belonging to the family Pinnidae.
Plantago lanigera is a species of flowering plant in the family Plantaginaceae that is endemic to New Zealand. Joseph Dalton Hooker described P. lanigera in 1864. Plants of this species of plantain are perennial with a rosette habit, leaves widest above the middle, few small angular to rounded seeds per capsule, glabrous bracts and sepals, and punctate leaves. It is listed as Not Threatened.
Plantago novae-zelandiae is a species of flowering plant in the family Plantaginaceae that is endemic to New Zealand. Lucy Moore described P. novae-zelandiae in 1961. Plants of this species of plantain are perennial with a rosette habit, leaves widest above the middle, up to 4 ellipsoid seeds per capsule, glabrous bracts and sepals, and punctate leaves. It is listed as Not Threatened.