Skull Variation

Skull
Geographic variation in the skull shape in the salamander Hynobius lichenatus (see below*). These specimens are stained with alizarinsulfonate (alizarin stain).

The skull shape of all specimens in a population (lower left: n = 60, Minakami-machi, Gunma Prefecture, Japan) differs articulately from that in other 18 localities examined, and the maxilla-maxilla length/snout-condyle length is the greatest of all populations examined. In this population, there are unusual lots of feet with unossified first centrale (54/120) and unossified tibiale (78/120), similar to those of H. hidamontanus (Pes Composition). Likewise, the unossification of fifth tarsale, which bears the fifth metatarsal, occurs in 20 specimens (this feature can be rarely found in others). This population, which corresponds to the southern limit of distribution for H. lichenatus, appears to be out of intraspecific variation in the osteological characters of this species.

*Unfortunately, only a proceeding of a talk written in Japanese is currently available; all specimens had been abandoned before I knew it (around March 1994), prior to getting detailed data on various measurements.


Copyright 2002 Masato Hasumi, Dr. Sci. All rights reserved.
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