Sphaeriidae is a
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
of small to minute freshwater
bivalve
Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...
mollusc
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...
s in the
order
Order, ORDER or Orders may refer to:
* A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
...
Sphaeriida. In the US, they are commonly known as pea clams or fingernail clams.
[ Heard, William H. 1977. Reproduction of fingernail clams (Sphaeriidae: ''Sphaerium'' and ''Musculium''). Malacologia, 16: 421-455.]
The Sphaeriidae is actually an important group of freshwater invertebrates, seeing as they play a huge role in the energy flow and the nutrient cycling within aquatic ecosystems, in which they constitute a food item for organisms of higher trophic levels and even contribute to the bioturbation of sediments which can help create a physical resource for many other species that utilize the shells.
Genera
Genera:
*
Euperinae
** ''
Byssanodonta''
d'Orbigny, 1846
** ''
Eupera''
Bourguignat, 1854
*
Sphaeriinae
** ''
Afropisidium''
Kuiper, 1962
** ''
Euglesa''
Jenyns, 1832
** ''
Musculium''
Link, 1807
** ''
Odhneripisidium''
Kuiper, 1962
** ''
Pisidium''
C. Pfeiffer, 1821
** ''
Sphaerium''
Scopoli, 1777
* fossils
** †''
Megasphaerioides''
Komatsu, J.-H. Chen & Q.-F. Wang, 2003
** †''
Protosphaerium''
Hocknull, 2000
** †''
Sphaericoncha''
Kolesnikov, 1980
Biology and ecology
Sphaeriidae are
hermaphrodite
A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic.
The individuals of many ...
s with internal fertilization. Developing young are incubated within their mother (
ovoviviparity
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop inside eggs that r ...
), and newborn clams look like miniature copies of the adults.
[
]Parasite
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...
s and/or predators include the Sciomyzidae
The family (biology), family Sciomyzidae belongs to the typical flies (Brachycera) of the order (biology), order Fly, Diptera. They are commonly called marsh flies, and in some cases snail-killing flies due to the food of their larvae.
Here, t ...
.
Taxonomy and conservation
The taxonomy of the Sphaeriidae has actually, up until present time, been severely challenging due to how small they are in size and their morphological similarities. The conservation status of this family has also been severely overlooked as there is a huge lack on basic knowledge of the Sphaeriidae, such as a lack of knowledge on their taxonomy, biology and even their ecology. Further research on the Sphaeriidae is extremely emphasized for a better detailed and understanding on the species.
References
{{Authority control
Bivalve families