It's too broad to identify a specific lineage. I do not quite understand why it would be assumed that evolution follows a strictly linear and narrow sequence over a long period of time. Another way to falsify message theory would be to provide an example that spans life on a sufficiently large scale. Actually, multiple examples could be required. Message theory would be refuted if the record contained clear-cut phylogeny of sufficient strength to span life on a large scale.
Message theory is testable science.
If these exist with sufficient strength to span the pattern of life, then message theory would be wrong and evolution would be right. When experimental demonstrations can span the gaps, then common descent of the spanned organisms is reasonably assured. This method is strong enough to unite any collection or organisms, without requiring further pattern. In principle, this method could prove evolution. Nonetheless, the gaps in life are much larger than experimental demonstrations.