Pisidium punctiferum
Encyclopedia
Pisidium punctiferum, common name Striate Peaclam, is a freshwater bivalve of the family
Sphaeriidae
.
, Trinidad
. They were collected by the government botanist Mr. H. Prestoe and by Robert John Lechmere Guppy
in 1867.
is somewhat subquadrately oval, thin, diaphanous, close, finely striate concentrically, whitish horny, or slightly tinted with fuscous patches near the umbo
nes, and covered with numerous granular points, which are finer and more crowded on the umbones, where the concentric striation is less evident. The shell is anteriorly rather short and subangulate, posteriorly a little truncate. The hinge
is with well-developed lateral teeth in both valves, 1-1/1-1. The cardinal teeth is small 2/2.
This curious little shell varies somewhat, and specimens are sometimes more oval and compressed than the one figured. Occasionally they are higher and shorter, with a steeper posterior slope. The granular points are more easily seen in dead shells, which are opaque. In living examples they seem, under a strong lens, to bear short hairs. The length of a large example is 4 mm, the height is 3.5 mm, the thickness is 2.5 mm. Of an average example the length is 3 mm, the height is 2.5 mm, the thickness is 2 mm.
Among species of the genus Pisidium the shell appear to resemble most Cyclas argentina D'Orb. (=? Pisidium agentina), and Cyclas calyculata Drap. (=? Pisidium calyculata). It is usually more equilateral than either of those species. The epidermis is thin and colourless, so that the striate gills may be seen through the shell. The umbones are not so prominent as those of Pisidium calyculata, but they are occasionally flattened or otherwise distorted. The foot is whitish translacid, and may be extruded to a length more than equalling that of the shell, the body being brought up to it with a jerk, as in allied species. Full-grown examples are slightly more equilateral and more angulate than young ones.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Sphaeriidae
Sphaeriidae
The Sphaeriidae are a family of small to minute freshwater bivalve molluscs, in the order Veneroida. In the USA they are commonly known as the pea clams and the fingernail clams.-Genera:Genera in the family Sphaeriidae include:* Musculium...
.
Distribution
The type locality is a pond at Saint Ann's River, near Port of SpainPort of Spain
Port of Spain, also written as Port-of-Spain, is the capital of the Republic of Trinidad and Tobago and the country's third-largest municipality, after San Fernando and Chaguanas. The city has a municipal population of 49,031 , a metropolitan population of 128,026 and a transient daily population...
, Trinidad
Trinidad
Trinidad is the larger and more populous of the two major islands and numerous landforms which make up the island nation of Trinidad and Tobago. It is the southernmost island in the Caribbean and lies just off the northeastern coast of Venezuela. With an area of it is also the fifth largest in...
. They were collected by the government botanist Mr. H. Prestoe and by Robert John Lechmere Guppy
Robert John Lechmere Guppy
Robert John Lechmere Guppy was a British-born naturalist after whom the guppy is named...
in 1867.
- USA:
- KentuckyKentuckyThe Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...
- VirginiaVirginiaThe Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
- IllinoisIllinoisIllinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
- northeast Florida
- Kentucky
- Dominica
- Brazil
Description
The shellBivalve shell
A bivalve shell is part of the body, the exoskeleton or shell, of a bivalve mollusk. In life, the shell of this class of mollusks is composed of two parts, two valves which are hinged together...
is somewhat subquadrately oval, thin, diaphanous, close, finely striate concentrically, whitish horny, or slightly tinted with fuscous patches near the umbo
Umbo
Umbo may refer to:*A shield boss* umbo , at the top of some mushrooms*The Umbo of tympanic membrane - a part of the human body*Umbo is the part of a Bivalve shell which was formed when the animal was a juvenile...
nes, and covered with numerous granular points, which are finer and more crowded on the umbones, where the concentric striation is less evident. The shell is anteriorly rather short and subangulate, posteriorly a little truncate. The hinge
Hinge
A hinge is a type of bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation. Hinges may be made of flexible material or of moving components...
is with well-developed lateral teeth in both valves, 1-1/1-1. The cardinal teeth is small 2/2.
This curious little shell varies somewhat, and specimens are sometimes more oval and compressed than the one figured. Occasionally they are higher and shorter, with a steeper posterior slope. The granular points are more easily seen in dead shells, which are opaque. In living examples they seem, under a strong lens, to bear short hairs. The length of a large example is 4 mm, the height is 3.5 mm, the thickness is 2.5 mm. Of an average example the length is 3 mm, the height is 2.5 mm, the thickness is 2 mm.
Among species of the genus Pisidium the shell appear to resemble most Cyclas argentina D'Orb. (=? Pisidium agentina), and Cyclas calyculata Drap. (=? Pisidium calyculata). It is usually more equilateral than either of those species. The epidermis is thin and colourless, so that the striate gills may be seen through the shell. The umbones are not so prominent as those of Pisidium calyculata, but they are occasionally flattened or otherwise distorted. The foot is whitish translacid, and may be extruded to a length more than equalling that of the shell, the body being brought up to it with a jerk, as in allied species. Full-grown examples are slightly more equilateral and more angulate than young ones.