Phyllidiidae
Encyclopedia
Phyllidiidae is a family
of sea slug
s, dorid nudibranch
s, marine
gastropod mollusks in the superfamily Phyllidioidea
.
This family is within the clade Euctenidiacea
(according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005
).
of these oval nudibranchs is flattened dorsoventrally and its dorsal surface is covered with hard, colored tubercle
s. This mantle is decorated with contrasting colors and patterns as warning signals to predators. The lamellate rhinophore
s can be retracted. Like other dorid nudibranchs, all species have a dorsal anus
, except for the species in the genus Fryeria where the anus is posteroventral and protrusible. In contrast with the other nudibranchs from the clade Doridacea
, the species in this family lack buccal armature, i. e. radula
e and jaws. The gill leaflets are situated along the ventral area and to the side (= ventrolateral ) instead of consisting of a dorsomedian ( = along the middle line of the upper surface) circlet . The oral glands, which are closely associated with the pharynx
and contained in the oral tube, and the stomach have undergone modifications. The female part in the reproductive system of these hermaphroditic snails has two separate openings and the male part one. This is called a triaulic reproductive system. It corresponds to the same triaulic condition of the advanced dorids.
Most phyllidiids occur in their natural context during day time in conspicuous way and show themselves exposed to the predators. However their colors are warning signals indicating special capabilities to deter predators, such as bioactive chemical defense. This phenomenon is called aposematism
. During observations, only one species was found always hidden : Phylliopsis cardinalis Bergh
has been observed feeding on a sponge of the genus Hymeniacidon
. Phyllidia flava has been reported feeding on the sponge Acanthella acuta
coined the words "les Phyllidiens" and "les phyllidéens" (1801; 1809). These were later latinized by J.G. Children (1823) to Phyllidiana, who put them in Hydrobranchiae. The present name Phyllidiidae is now attributed to Rafinesque and not to Lamarck.
There has been much confusion in the taxonomy of this family, caused by inadequate descriptions. David J. Brunckhorst in his book "The Systematics and Phylogeny of Phyllidiid Nudibranchs (Doridoidea)" has brought a thorough review of this family.
Phylogenetic
analysis through cladistics
shows that the family Phyllidiidae is monophyletic. The phylogenetic tree
shows that Ceratophyllidia is sister to the rest of the family and Phyllidiopsis sister to the remaining genera, Phyllidiella sister to the remaining genera, and Reticulidia sister to Phyllidia and Fryeria.
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 sea slug
Slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...
s, dorid nudibranch
Nudibranch
A nudibranch is a member of what is now a taxonomic clade, and what was previously a suborder, of soft-bodied, marine gastropod mollusks which shed their shell after their larval stage. They are noted for their often extraordinary colors and striking forms...
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 mollusks in the superfamily Phyllidioidea
Phyllidioidea
Phyllidioidea is a taxonomic superfamily of colorful sea slugs, dorid nudibranchs, marine gastropod mollusks.-Taxonomy:*Family Phyllidiidae Rafinesque, 1814*Family Dendrodorididae O'Donoghue, 1924*Family Mandeliidae Valdés & Gosliner, 1999...
.
This family is within the clade Euctenidiacea
Euctenidiacea
The Euctenidiacea are a taxonomic family of sea snails or slugs, marine gastropod molluscs in the order Notaspidea.A phylogenetical study, published in 2000, by Wägele & Willan has shown that the subclade Gnathodoridacea and the subclade Doridacea each form a monophyletic group.In a later study,...
(according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005
Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)
The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...
).
Distribution
Most species occur in the tropical Indo-Pacific region, but a few species have been found in the tropical Atlantic Ocean and in the Mediterranean.Description
The mantleMantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
of these oval nudibranchs is flattened dorsoventrally and its dorsal surface is covered with hard, colored tubercle
Tubercle
A tubercle is generally a wart-like projection, but it has slightly different meaning depending on which family of plants or animals it is used to refer to....
s. This mantle is decorated with contrasting colors and patterns as warning signals to predators. The lamellate rhinophore
Rhinophore
A rhinophore is one of a pair of club-shaped structures which are the most prominent part of the external head anatomy of a group of sea slugs, marine gastropod opisthobranch mollusks in the order Nudibranchia, the nudibranchs, specifically the dorid nudibranchs.- Etymology :The name relates to the...
s can be retracted. Like other dorid nudibranchs, all species have a dorsal anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
, except for the species in the genus Fryeria where the anus is posteroventral and protrusible. In contrast with the other nudibranchs from the clade Doridacea
Doridacea
Doridacea is a taxonomic grouping of dorid nudibranchs, shell-less marine gastropod mollusks. included in the clade Euctenidiacea of the clade Nudibranchia.- Taxonomy :*Superfamily Doridoidea**Family Dorididae**Family Actinocyclidae...
, the species in this family lack buccal armature, i. e. 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...
e and jaws. The gill leaflets are situated along the ventral area and to the side (= ventrolateral ) instead of consisting of a dorsomedian ( = along the middle line of the upper surface) circlet . The oral glands, which are closely associated with the pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
and contained in the oral tube, and the stomach have undergone modifications. The female part in the reproductive system of these hermaphroditic snails has two separate openings and the male part one. This is called a triaulic reproductive system. It corresponds to the same triaulic condition of the advanced dorids.
Most phyllidiids occur in their natural context during day time in conspicuous way and show themselves exposed to the predators. However their colors are warning signals indicating special capabilities to deter predators, such as bioactive chemical defense. This phenomenon is called aposematism
Aposematism
Aposematism , perhaps most commonly known in the context of warning colouration, describes a family of antipredator adaptations where a warning signal is associated with the unprofitability of a prey item to potential predators...
. During observations, only one species was found always hidden : Phylliopsis cardinalis Bergh
Feeding habits
There are not many reports on the ecology and the feeding habits of these nudibranchs. As their small mouth lacks a radula and other buccal hard parts, they are known as predators adapted for sucking on sponges. Phyllidia varicosaPhyllidia varicosa
Phyllidia varicosa is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Phyllidiidae.- Distribution :...
has been observed feeding on a sponge of the genus Hymeniacidon
Hymeniacidon
Hymeniacidon is a genus of sponges in the class Demospongiae. Some members of the genus are known to be mobile, achieving speeds of between 1 and 4mm per day.-Species:Species so far described in this genus include:...
. Phyllidia flava has been reported feeding on the sponge Acanthella acuta
Taxonomy
The original spelling was denoted as family Phyllidia. Jean-Baptiste LamarckJean-Baptiste Lamarck
Jean-Baptiste Pierre Antoine de Monet, Chevalier de la Marck , often known simply as Lamarck, was a French naturalist...
coined the words "les Phyllidiens" and "les phyllidéens" (1801; 1809). These were later latinized by J.G. Children (1823) to Phyllidiana, who put them in Hydrobranchiae. The present name Phyllidiidae is now attributed to Rafinesque and not to Lamarck.
There has been much confusion in the taxonomy of this family, caused by inadequate descriptions. David J. Brunckhorst in his book "The Systematics and Phylogeny of Phyllidiid Nudibranchs (Doridoidea)" has brought a thorough review of this family.
Genera
The family Phyllidiidae consists of six genera with a total of more than 80 species.- PhyllidiaPhyllidiaPhyllidia is a genus of sea slugs, dorid nudibranchs, shell-less marine gastropod molluscs in the family Phyllidiidae.-Species:Species in the genus Phyllidia include:* Phyllidia alyta Yonow, 1996* Phyllidia babai Brunckhorst, 1993...
CuvierGeorges CuvierGeorges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
, 1797 (type genusType genusIn biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
) - CeratophyllidiaCeratophyllidiaCeratophyllidia is a genus of sea slugs, dorid nudibranchs, shell-less marine gastropod molluscs in the family Phyllidiidae.They are known for their unusually soft, spherical and stalked tubercules on their upper dorsums...
Eliot, 1903 - FryeriaFryeriaFryeria is a genus of sea slugs, dorid nudibranchs, shell-less marine gastropod molluscs in the family Phyllidiidae.-Species:Species in the genus Fryeria include:* Fryeria bayi Bouchet, 1983* Fryeria guamensis Brunckhorst, 1993...
Gray, 1853 - PhyllidiellaPhyllidiellaPhyllidiella is a genus of sea slugs, dorid nudibranchs, shell-less marine gastropod molluscs in the family Phyllidiidae.-Species:Species in the genus Phyllidiella include:* Phyllidiella annulata...
BerghRudolph BerghRudolph Bergh , full name Ludvig Sophus Rudolph Bergh, was a Danish physician and malacologist. He worked in Copenhagen....
, 1869 - PhyllidiopsisPhyllidiopsisPhyllidiopsis is a genus of sea slugs, dorid nudibranchs, shell-less marine gastropod molluscs and is the largest genus within the family Phyllidiidae....
BerghRudolph BerghRudolph Bergh , full name Ludvig Sophus Rudolph Bergh, was a Danish physician and malacologist. He worked in Copenhagen....
, 1875 - ReticulidiaReticulidiaReticulidia is a genus of sea slugs, dorid nudibranchs, shell-less marine gastropod molluscs in the family Phyllidiidae.-Species:Species in the genus Reticulidia include:* Reticulidia fungia Brunckhorst & Gosliner in Brunckhorst, 1993...
Brunckhorst, 1990
Phylogenetic
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
analysis through cladistics
Phylogenetic nomenclature
Phylogenetic nomenclature or phylogenetic taxonomy is an alternative to rank-based nomenclature, applying definitions from cladistics . Its two defining features are the use of phylogenetic definitions of biological taxon names, and the lack of obligatory ranks...
shows that the family Phyllidiidae is monophyletic. The phylogenetic tree
Phylogenetic tree
A phylogenetic tree or evolutionary tree is a branching diagram or "tree" showing the inferred evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical and/or genetic characteristics...
shows that Ceratophyllidia is sister to the rest of the family and Phyllidiopsis sister to the remaining genera, Phyllidiella sister to the remaining genera, and Reticulidia sister to Phyllidia and Fryeria.