Pleurotomariidae
Encyclopedia
Pleurotomariidae, common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...

 the '"slit snails", is a family
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...

 of large marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropods in the clade Vetigastropoda
Vetigastropoda
Vetigastropoda is a major taxonomic group of sea snails, marine gastropod mollusks that form a very ancient lineage. Taxonomically Vetigastropoda are sometimes treated as an order although they are a clade in Bouchet and Rocroi, 2005....

. This family is very ancient; there were numerous species in the geological past. It is currently represented by a group of species that live only in deep water. This family has no subfamilies.

The first living specimens of a species in this family, Perotrochus quoyanus, were dredged in 1879 in deep water off the West Indies by the "Blake" expedition of William Healey Dall.http://books.google.com/books?id=pMpMAAAAYAAJ&pg=PA583&lpg=PA583&dq=discovery+of+living+pleurotomaria&source=bl&ots=Zsdr0UHjKA&sig=gJJ2tH_t39qC_NQekKnvlSPmi7I&hl=en&ei=eTrSTuTKGary0gGzxrRA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CCQQ6AEwAQ#v=onepage&q=discovery%20of%20living%20pleurotomaria&f=false

Description

The innermost shell layer of Pleurotomariidae is composed of nacre
Nacre
Nacre , also known as mother of pearl, is an organic-inorganic composite material produced by some mollusks as an inner shell layer; it is also what makes up pearls. It is very strong, resilient, and iridescent....

. There is a deep slot in the palatal wall of the aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....

. This slot is used for respiration. The slot is sealed up gradually behind the advancing aperture.

Fossil record

The Pleurotomariidae have a continuous fossil record from the Upper Cambrian onwards. After taking a considerable hit at the K-T extinction, they have been restricted to deeper waters through the Cenozoic. In 2009, a new study in the Journal of Paleontology
Journal of Paleontology
The Journal of Paleontology is a peer-reviewed scientific journal covering the field of paleontology, published by The Paleontological Society.-Indexing:The Journal of Paleontogy is indexed in:*BIOSIS Previews*Science Citation Index...

described the first occurrence of Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

 pleurotomariids from Antarctica.

Ecology

Species in the family Pleurotomariidae live at depths of 2000-3000 m as benthos
Benthos
Benthos is the community of organisms which live on, in, or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.Many organisms...

 on the bottom in the bathyal zone
Bathyal zone
The bathyal zone or bathypelagic – from Greek βαθύς , deep – is that part of the pelagic zone that extends from a depth of 1000 to 4000 metres below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below. The average temperature hovers at about 39°F...

.

They are preyed upon by crustacea and fish, but are remarkably resistant to attack — they secrete a white fluid when endangered, thought to repel predators. They feed primarily on sponges, and supplement their diet with crinoids and octocorals in the wild; in aquaria, they also feed on fish and clam tissue.

Genera

Genera within the Pleurotomariidae include:
  • Bayerotrochus
    Bayerotrochus
    Bayerotrochus is a genus of sea snails, marine gastropod mollusks in the family Pleurotomariidae.The generic name Bayerotrochus is in honor of marine biologist Frederick Bayer.-Species:Species within the genus Bayerotrochus include:...

    Harasewych, 2002
  • Entemnotrochus
    Entemnotrochus
    Entemnotrochus is a genus of large to very large deepwater sea snails with gills and an operculum, marine gastropod mollusks in the family Pleurotomariidae, the slit snails.-Species:...

    Fischer, 1885
  • Mamoeatomaria Begg & Grant-Mackie, 2006
  • Mikadotrochus
    Mikadotrochus
    Mikadotrochus is a genus of sea snails, marine gastropod mollusks in the family Pleurotomariidae, the slit snails.-Species:Species within the genus Mikadotrochus include: * Mikadotrochus anseeuwi...

    Lindholm, 1927
  • Perotrochus
    Perotrochus
    Perotrochus is a genus of large sea snails with gills and an operculum, marine gastropod mollusks in the family Pleurotomariidae, the slit snails, .- Species :...

    Fischer, 1885
  • Pleurotomaria
    Pleurotomaria
    Pleurotomaria is a genus of sea snails, marine gastropod mollusks in the family Pleurotomariidae.-Species:Species within the genus Pleurotomaria include:Species brought into synonymy :...

    Sowerby, 1821
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