Each ionized molecular species obtained in the 41 mass spectra
was considered as a different character with two different states,
present (1) or absent (0). A total of 444 characters were coded,
and the matrix obtained was analyzed using MrBayes
(Huelsenbeck et al., 2001). Two parallel analyses were performed,
each consisting of eight Markov chains of 10,000,000 generations.
Convergence of the runs was tested as described previously. A consensus
tree was calculated after omitting the first 25% trees as
burn-in. The absence of outgroup in this analysis is due to the
unavailability of venom for closely related species, and to the fact
that venom available for more distant species had almost no mass
in common with the three species of the lividus complex.