The book lungs of Scorpiones and Tetrapulmonata (Chelicerata, Arachnida): evidence for homology and a single terrestrialisation event of a common arachnid ancestor.

The question of whether Arachnida (Chelicerata) conquered terrestrial habitats only once or several times is controversial. The key group in this respect is the Scorpiones. Several authors claim that they became terrestrial independently of other arachnid lineages. This argumentation uses two lines of evidence. One is that book lungs of scorpions and other… (More)