Bursidae
Encyclopedia
Bursidae, 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...

 "frog snails" or "frog shells" is a rather small taxonomic 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 sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....

s, 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...

 gastropod predatory snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s in the clade Littorinimorpha
Littorinimorpha
Littorinimorpha is a large clade of gastropods within Hypsogastropoda consisting primarily of marine species, but also aquatic and terrestrial species as well....

.

Distribution

Most species in this family occur on rocks or coral reefs in shallow waters of tropical oceans, including the Indo-Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...

, the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....

 and other marginal warm seas. But they are also found in the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 and the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...

. Only a few are found on sandy bottoms of deeper waters of the continental shelf.

Shell description

The thick, ovate to slightly elongate shells are coarsely sculptured, resembling the triton shells of the Ranellidae
Ranellidae
Ranellidae, common name the triton shells or tritons, is a taxonomic family of small to very large predatory sea snails, marine gastropod mollusks in the clade Littorinimorpha.-Subfamilies:...

. The intersection of the spiral ribs
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...

 and the axial sculpture results in a strong nodulose pattern of more or less round knobs. This warty surface gave them their common name - frog shells. The outer varicose lip is dilated and shows a number of labial plicae, resulting in a toothed lip on the inside. The inner lip is calloused, showing transverse plicae.

The anterior and posterior canals are well developed. The siphonal canal
Siphonal canal
Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. In many carnivorous snails, where the siphon is particularly long, the structure...

 at the anterior end is usually short. The anal canal at the posterior end is a deep slot. The strong axial varices
Varix (mollusc)
A varix is an anatomical feature of the shell of certain sea snails, marine gastropod molluscs.It is a thickened axial ridge in the shell of some families of gastropods. A varix is located at intervals around the whorl, and is formed by considerable thickening of the outer lip at a resting stage...

 are often in two continuous series per whorl, one down each side of the shell. The nucleus of the corneous operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...

 is situated either at the anterior end or the mid-inner margin. A periostracum
Periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...

 (hairy covering of the outer shell) is usually absent or thin.

Anatomy

The taenioglossate radula
Radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...

 has seven teeth in each row: one central tooth, flanked on each side by one lateral and two marginal teeth. The central tooth is saddle-shaped, with long basal limbs, each bearing a cusp-like spur upon its face.

Their eyes are based at the base of their filiform tentacle
Tentacle
A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...

s. The foot is short and thick.

Fertilization is internal. The female snail lays her eggs enclosed in a jelly-like matrix that she sometimes broods with her foot. After hatching, the eggs become free-swimming larvae.

Feeding habits

Frog shells are active predators, and appear to feed on bristle worms (Polychaeta) that they anaesthetize with acidic saliva through their extensible, distally flattened proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...

.

Genera

genera in the family Bursidae include:
  • Genus Bufonaria
    Bufonaria
    Bufonaria is a genus of medium-large sea snails, marine gastropod mollusks in the family Bursidae, the "frog snails". -Species:Species within the genus Bufonaria may include: * Bufonaria cavitensis...

    Schumacher, 1817
    • Bufonaria bufo Bruguiere
      Jean Guillaume Bruguière
      Jean Guillaume Bruguière was a French physician, zoologist and diplomat.Bruguière was born in Montpellier.He was a doctor, connected to the University of Montpellier. His was interested in invertebrates, mostly snails ....

      , 1792
      - chestnut frogsnail
    • Bufonaria borisbeckeri Parth, 1996 - named after Boris Becker
      Boris Becker
      Boris Franz Becker is a former World No. 1 professional tennis player from Germany. He is a six-time Grand Slam singles champion, an Olympic gold medalist, and the youngest-ever winner of the men's singles title at Wimbledon at the age of 17...

  • Genus Bursa
    Bursa (genus)
    Bursa is a genus of large sea snails, marine gastropod mollusks in the family Bursidae, the frog snails or frog shells. -Species:Species within the genus Bursa include :* Bursa affinis...

    Roding, 1798
  • Genus Bursina
    Bursina
    Bursina is a genus of sea snails, marine gastropod mollusks in the family Bursidae, the frog shells.-Species:Species within the genus Bursina include:* Bursina borisbeckeri * Bursina fernandezi...

    Oyama 1964 - assigned to Bursidae by Beu in 2005
  • Genus Crossata
    Crossata
    Crossata is a genus of sea snails, marine gastropod mollusks in the family Bursidae, the frog shells.-Species:Species within the genus Crossata include:* Crossata ventricosa...

    Jousseaume, 1881
    • Crossata californica Hinds, 1843 - California frogsnail
  • Genus Marsupina Dall, 1904
  • † Genus Ranellina - assigned to Bursidae by Palmer and Brann in 1966
  • Genus Tutufa
    Tutufa
    Tutufa is a genus of sea snails, marine gastropod mollusks in the family Bursidae, the frog shells.-Species:Species within the genus Tutufa include:* Tutufa bardeyi * Tutufa bubo...

    Jousseaume, 1881

External links

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