I have created my own phylogenetic tree as follows.

I am having trouble resolving the error no matter how I try.

Is there something wrong with the way I created it?

I want to use gls.ancova function in "evomap". Please help me!

newick_tree<-"(A:4,(B:2,(C:2.953469601,D:1.443532938):1.136357167):1.104667235);"

phylo_tree <- read.tree(text = newick_tree)

vcv(phylo_tree)

A B C D

A 4 0.000000 0.000000 0.000000

B 0 3.104667 1.104667 1.104667

C 0 1.104667 5.194494 2.241024

D 0 1.104667 2.241024 3.684557

gls.ancova(log_lifespan ~ body_size, vcv(phylo_tree), Model, Model_I)

Error in solve.default(Sigma) :

Lapack routine dgesv: system is exactly singular: U[1,1] = 0