Phylogenetic varieties are algebraic varieties specified by a statistical model
describing the evolution of biological sequences along a tree. Its understanding is an
important problem in algebraic statistics, particularly in the context of phylogeny
reconstruction. In the broader area of algebra statistics, there have been important
theoretical advances in computing certain invariants associated with algebraic
varieties arising in applications. Beyond the dimension and degree of a variety, one is
interested in computing other algebraic degrees, such as the maximum likelihood
degree and the Euclidean distance degree. Despite these efforts, the current literature
lacks explicit computations of these invariants for the particular case of phylogenetic
varieties. In our work, we fill this gap by computing these invariants for phylogenetic
varieties arising from the simplest group-based models of nucleotide substitution
Cavender–Farris–Neyman model, Jukes–Cantor model, Kimura 2-parameter model
and the Kimura 3-parameter model on small phylogenetic trees with at most 5 leaves.