Philomycidae are a family of air-breathing land slugs (snails without shells or with only shell remnants). They are terrestrial

Terrestrial animal

Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 pulmonate gastropod mollusks in the superfamily Arionoidea

Arionoidea

Arionoidea is a taxonomic group, a superfamily of air-breathing land slugs, shell-less terrestrial pulmonate gastropod mollusks.- Families :Families within the superfamily Arionoidea include:* Arionidae* Anadenidae* Ariolimacidae* Binneyidae...

 (according 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...

).

The family Philomycidae has no subfamilies.

Distribution

Slugs in this family are found in China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

, Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, the East Indies

East Indies

East Indies is a term used by Europeans from the 16th century onwards to identify what is now known as Indian subcontinent or South Asia, Southeastern Asia, and the islands of Oceania, including the Malay Archipelago and the Philippines...

, central and eastern North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, and through Central America

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

 into northern South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

.

Anatomy

Members of this family most obviously differ from related slugs in that their mantles are broadly rounded, and very large, covering the entire body. (In mollusks, the mantle consists of the tissues that normally generate the shell. Being mostly or entirely without shells, most slugs have reduced mantles.)

Pilsbry (1948) stated that the enormously developed mantle

Mantle (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...

, the large empty shell sac, and the insertions of the free retractor muscles along the margins of the foot cavity, instead of dorsally as in the Arionidae

Arionidae

Arionidae, common name the "roundback slugs" or "round back slugs" are a taxonomic family of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the superfamily Arionoidea.- Distribution :...

 are special to the Philomycidae.

A further anatomical oddity of the group, shared with certain helicid and zonitid snails, is their creation and use of calcareous love dart

Love dart

A love dart is a hard, long, sharp, calcareous or chitinous dart which some hermaphroditic land snails and slugs create. Love darts are made in sexually mature animals only, and are used as part of the sequence of events during courtship, before actual mating takes place...

s during mating.

In this family, the number of haploid chromosome

Chromosome

A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

s lies between 21 and 30 (according to the values in this table).

Genera

Genera within the family Philomycidae include:

• Megapallifera
  Megapallifera
  Megapallifera is a genus of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Philomycidae.-References:*...
  
  Hubricht, 1956
• Meghimatium
  Meghimatium
  Meghimatium is a genus of medium to large air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Philomycidae and the superfamily Arionoidea, the roundback slugs.-Species:Species within the genus Meghimatium include:...
  
  Hasselt, 1823 - synonym: Incilaria Benson, 1842
• Pallifera Morse, 1864
• Philomycus
  Philomycus
  Philomycus, common name the mantleslugs, is a genus of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Philomycidae.- Species :Species within the genus Philomycus include:* Philomycus batchi - dusky mantleslug...
  
  Rafinesque, 1820 - the type genus

Cladogram

A cladogram

Cladogram

A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...

 based on sequences of cytochrome-c oxidase I

Main subunit of cytochrome c oxidase

Cytochrome C and Quinol oxidase polypeptide I is main subunit of cytochrome c oxidase complex.Cytochrome c oxidase is a key enzyme in aerobic metabolism. Proton pumping heme-copper oxidases represent the terminal, energy-transfer enzymes of respiratory chains in prokaryotes and eukaryotes...

 (COI) genes showing phylogenic relations of genera in the family Philomycidae by Tsai & Wu (2008) (simplified):
Arion and Deroceras were used as outgroup.

External links

• Slugs of Florida on the UF
  University of Florida
  The University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
  
   / IFAS
  Institute of Food and Agricultural Sciences
  The University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...
  
  Featured Creatures Web site