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THE SALAMANDERS OF THE FAMILY HYNOBIIDAE. 1 



By Emmett Reid Dunn. 



Received January 29, 1923. Presented by Thomas Barbour. 



The Salamander family Hynobiidae is a group of some five genera 

 and twenty-one species. They are animals of northern Asia, the Urals 

 and the mountains of Sze-chuan marking their extreme outposts to the 

 West and to the South. A species of one of the genera (Ranodon 

 olympicus Gaige) has been recorded from North America, but I have 

 shown that this animal is not a Ranodon, and should be considered as 

 the type of a distinct genus Rhyacotriton, which belongs to the Amby- 

 stomidae, and is most closely related to the genus Dicamptodon. 

 (Proc. New England Zool. Club, VII, p. 55, 1920). 



The relationships of the family are with the large river-salamanders, 

 the Cry ptobranchidae . If the Hynobiidae are not directly ancestral to 

 these, at least they represent very well the less modified type from 

 which such flattened, aquatic forms must have arisen. That the 

 Cry ptobranchidae are known from as far back as the Oligocene compels 

 us to assume a still earlier era as the time of origin of the Hynobiidae. 

 The characters on which this relationship is based serve also to dis- 

 tinguish between the Hynobiidac-Cry ptobranchidae on the one hand 

 and the remaining groups of salamanders on the other. To express 

 this relationship I have proposed the superfamily name Crypto- 

 branchoidea. (Amer. Nat. LVI, p. 418, 1922). These are certainly 

 not derived from any existing group of salamanders, nor is it possible 

 to point out any groups descended from them. 



From a phylogenetic standpoint Hynobius occupies a central posi- 

 tion, the other four genera showing various secondary modifications. 



Within the genus Hynobius itself the Korean form, H. leechii, 

 apparently represents the stock from which the other forms have 

 descended. The other continental species, chinensis, turkestanicus, 

 and keyserlingii, each bear marks of specialization. These four forms 

 occupy separate areas. To the eastward, however, in the islands, 

 the situation is more complex, as many as four forms of Hynobius 

 occurring on Hondo. 



The species of Sakhalin, Hynobius cristatus, seems to have been 

 derived from keyserlingii of the opposite mainland. 



1 Contributions from the Department of Zoology, Smith College, No. 105. 



