Corner teeth

Lugfish - small-sized or medium-sized tailed amphibians (up to 200 mm, genus Ranodon ), living mainly in Asia , except for one species, the Siberian lugfish ( Salamandrella keyserlingii ), which penetrates the European part of Russia . The life cycle is typical of a two-stage amphibian, with an aquatic larva and adult individuals leading an aquatic or terrestrial lifestyle. Larvae with external gills , 4 pairs of gill slits and tail filament. Adults after metamorphosis outside the breeding season live on land, except for the constant- water representatives of the genera Batrachuperus , Liua, and Pachyhynobius . Adults have well-developed lungs, with the exception of pulmonary newts of the genus Onychodactylus . Fertilization is external.

Among other caudate amphibians, the anglerfish are distinguished by a large number of chromosomes in the karyotype (up to 78 in the diploid set), and the presence of an angular bone (os angulare) in the lower jaw. The latter trait, along with other structural features of the skeleton, is considered primitive for the order, where there is a clear tendency to reduce bone elements, and allows us to talk about maw teeth as a group most similar to the oldest common ancestors of all tailed amphibians.

Looters are also the only family in the squad, limited in their distribution by Eurasia. The range of the family on the continent is vast, but extremely torn: found from Iran to Japan , the greatest species diversity is observed in East Asia. One species, the aforementioned Siberian lump ( Salamandrella keyserlingii ), lives in a vast area from the Arkhangelsk and Nizhny Novgorod regions in the west to Chukotka , Kamchatka and Hokkaido in the east and from the forest-tundra zone in the north to the forest-steppes in the south, although mountainous species prevail in the group species with tiny ranges covering the slopes of a small ridge or even one mountain. From other Asian tailed salamander ( Salamandridae ) with warty skin and giant neotenic salamanders from the family of cryptobranchs ( Cryptobranchidae ), the angler teeth easily differ in their appearance.

Different types of caviar are laid in current or standing water bodies. Each masonry is usually a pair of gelatinous caviar bags containing eggs and attached to stones or underwater plants. The shape, size of the eggs, the method of packing eggs in them are a taxonomic characteristic and serve to establish the relationship between genera.

Tailed amphibians of small or medium size. The skin is smooth. There are movable eyelids . Fertilization is external. Representatives of the family are characterized by another 8 morphological characters listed below, which are also used to establish their phylogenetic relationships with other groups of caudate amphibians:

1. the presence of cloisonne maxillary bones (ossa septomaxillaria);
2. the presence of lacrimal bones (ossa lacrimalia);
3. rows of openers are directed at an angle to the rows of marginal (actually jaw) teeth, and not parallel, which reflects the Russian name of the family;
4. ribs with one head;
5. amphitic vertebrae ;
6. the presence of external gills, 4 pairs of gill slits and caudal filament in larvae, complete loss of these characters during metamorphosis in adults; moving eyelids in adults;
7. eggs are laid in water in paired gelatinous bags with external fertilization;
8. lungs in adults are well developed, with the exception of the genus Onychodactylus.

Separately taken, these signs in many cases are also found in other caudate and cannot be considered as synapomorphies for angloids. The absence of signs found in other groups was indicated if this is a hallmark of the coral tooth or indicates a relationship with other groups of caudate amphibians.

More detailed morphological features of the family are taken from Duellman and Trueb (1986), Larson (1991) and Larson and Dimmick (1993):

Skull

Features:

• premaxillary bones (ossa premaxillaria) paired or fused into one bone (premaxilla);
• nasal bones (ossa nasalia) paired, adjacent to each other, being only partially separated by a short posterior process of premaxilla, ossify from 2 foci, medially and laterally located on the bone;
• maxillary bones (ossa maxillaria) are well developed;
• the presence of cloisonne maxillary bones (ossa septomaxillaria);
• the presence of lacrimal bones (ossa lacrimaria);
• lack of squamous bones (ossa quadratojugularia);
• lack of pterygoid bones (ossa pterygoidea);
• lack of an opening of an internal carotid artery on a parasphenoid;
• angular bone (os angulare) is not fused with the mandibular (mandibula);
• the column (columella) and operculum are present as separate auricles, separated from the auditory capsule in a number of species, while in others the operculum disappears;
• the opener teeth are replaced starting from the back of the opener;
• teeth have a distinct crown and neck;
• the front surface of the muscle that raises the lower jaw (musculus levator mandibulae) includes elements that are extra-occipital in origin.

Inner Ear

The basilar complex is presented;

• amphibious recess (recessus amphibiorum) in the inner ear is oriented horizontally;
• auditory sac (saccus oticus) bulbar and non-vascularized;
• amphibious perilymphatic canal (canalis perioticus) without fibrous tissue;
• The peri- lymphatic cistern (cysterna periotіsa) is large and does not protrude through the oval window (fenestra).

Torso and limb skeleton

- scapula and coracoid fused;
- vertebral bodies are amphicel;
- ribs with one head;
- in the neural arches there are no openings of the spinal nerves , the latter extend between adjacent arches.

At the beginning of the 1980s, the family included about 30 species belonging to 5 genera ( Hynobius, Batrachuperus, Ranodon, Onychodactylus, and Salamandrella ). Over the past quarter century, the number of known lumps has increased to 10 genera and 50 species, and many new species were previously completely unknown to science, and were not isolated as a result of a detailed study of the already described, as is often the case in modern bathrachology . Also changed the idea of ​​the taxonomy of the group at the birth level. The studies, including molecular genetic studies, forced the separation of East and West Asian representatives of the genera of frog-toothed ( Ranodon ) and alpine angliot ( Batrachuperus ), recognizing their similarity as convergent . Thus, according to modern concepts, the squad system looks like this:

Subfamily of the Pretooth Tooth ( Protohynobinae Fei et Ye, 2000)

• Genus of the Antarctal ( Protohynobius Fei et Ye, 2000)
  • East Asian Preglottus ( Protohynobius puxiongensis Fei et Ye, 2000)

Sub-family Carbon-Toothed ( Hynobiinae Cope, 1859)

• Genus Pseudohynobius Fei et Yang, 1983
  • Pseudohynobius flavomaculatus Hu and Fei in Hu, Fei et Ye, 1978
  • Pseudohynobius kuankuoshuiensis Xu, Zeng et Fu, 2007
  • Pseudohynobius shuichengensis Tian, ​​Li et Gu, 1998
• Genus Pulmonary Tritons ( Onychodactylus Tschudi, 1838)
  • Ussuri clawed newt ( Onychodactylus fischeri Boulenger, 1886)
  • Japanese Pulmonary Triton ( Onychodactylus japonicus Houttuyn, 1782)
• Genus Middle Eastern Carrier ( Paradactylodon Risch, 1984)
  • Elbur Carrier ( Paradactylodon gorganensis Clergue-Gazeau et Thorn, 1979)
  • Afghan Carbon Tooth ( Paradactylodon mustersi Smith, 1940)
  • Hyrcanic Coral Tooth ( Paradactylodon persicus Eiselt et Steiner, 1970)
• Frogtooth genus ( Ranodon Kessler, 1866)
  • Semirechye frog-tooth ( Ranodon sibiricus Kessler, 1866)
• Genus Chunky Coral Tooth ( Pachyhynobius Fei, Qu et Wu, 1983)
  • Chunky Shredder ( Pachyhynobius shangchengensis Fei, Qu et Wu, 1983)
• Clan Teeth ( Hynobius Tschudi, 1838)
  • Bamboo Charcoal Tooth ( Nynobius abei Sato, 1934)
  • Hynobius amjiensis Gu, 1992
  • Hynobius arisanensis maki , 1922
  • The Tooth of Boulanger ( Nynobius boulengeri Thompson, 1912)
  • Chinese Carbon Tooth ( Hynobius chinensis Günther, 1889)
  • Light Brown Carbon Tooth (Dunn Carrier ) ( Hynobius dunni Tago, 1931)
  • Formosa Carbon Tooth ( Hynobius formosanus Maki, 1922)
  • Hynobius guabangshanensis Shen, Deng et Wang, 2004
  • Hynobius hidamontanus Matsui, 1987
  • Spotted Carrier ( Hynobius kimurae Dunn, 1923)
  • Korean Carbon Tooth ( Hynobius leechii Boulenger, 1887)
  • Silver Carbon Tooth ( Hynobius lichenatus boulenger , 1883)
  • Hynobius maoershanensis Zhou, Jiang et Jiang, 2006
  • Spotted Carbon Tooth ( Hynobius naevius Temminck et Schlegel, 1838)
  • Smoky Shank Tooth , or Japanese Shag ( Hynobius nebulosus Temminck et Schlegel, 1838)
  • Black Coral Tooth ( Hynobius nigrescen Stejneger, 1907)
  • Dark Brick Carbon Tooth ( Hynobius okiensis Sato, 1940)
  • Hynobius quelpartensis Mori, 1928
  • Hokkaido Carbon Tooth ( Hynobius retardatus Dunn, 1923)
  • Taiwanese Lugfish ( Hynobius sonani Maki, 1922)
  • Amber Shredder ( Hynobius stejnegeri Dunn, 1923)
  • Plain Carbon Tooth ( Hynobius takedai Matsui et Miyazaki, 1984)
  • Tokyo Shredder ( Hynobius tokyoensis Tago, 1931)
  • Tsushima coal-toothed ( Hynobius tsuensis Abé, 1922)
  • Turkestan lugfish ( Hynobius turkestanicus Nikolsky, 1909)
  • Hynobius yangi Kim, Min et Matsui, 2003
  • Hynobius yiwuensis Cai, 1985
  • Hynobius yunanicus Chen, Qu et Niu, 2001
• Genus Siberian Coals ( Salamandrella Dybowski, 1870)
  • Siberian Coral Tooth ( Salamandrella keyserlingii Dybowski, 1870)
  • Seaside Carbon Tooth ( Salamandrella tridactyla Nikolsky, 1905)
• Genus Alpine Angliot ( Batrachuperus Boulenger, 1878)
  • Batrachuperus cochranae Liu, 1950
  • Batrachuperus karlschmidti Liu, 1950
  • large lump ( Batrachuperus londongensis Liu et Tian in Liu, Hu, Tian et Wu, 1978)
  • Sichuan coal-toothed ( Batrachuperus pinchonii David, 1872)
  • Batrachuperus taibaiensis Song, Zeng, Wu, Liu et Fu, 2001
  • Tibetan Carbon Tooth ( Batrachuperus tibetanus Schmidt, 1925)
  • Long-tailed Coral Tooth ( Batrachuperus yenyuanensis Liu, 1950)
• Genus Sichuan Frogtooth ( Liua Zhao et Hu, 1983)
  • Sichuan Frogtooth ( Liua shihi Liu, 1950)
  • Qingpai Frogtooth ( Liua tsinpaensis Liu et Hu in Hu, Zhao, et Liu, 1966)

The Siberian coal-toothed was returned to life after hundreds of years in cryogenic suspended animation . ^[2]

• Life of animals, v. 5. Amphibians and reptiles. Ed. A. G. Bannikova - M .: "Enlightenment", 1985.
• Larson, A., DW Weisrock, and KH Kozak. 2003. Phylogenetic systematics of salamanders (Amphibia: Urodela), a review. Pp. 31-108 in Reproductive Biology and Phylogeny of Urodela (DM Sever, ed.) Science Publishers, Inc., Enfield (NH), USA.

• General characteristics of the group of materials Tree of Live web project
• Taxonomic information on Amphibian Species of the World 5.1
• Family Views on AmphibiaWeb
• Names used in Russian literature