A recent article
describes minute insects that are on or close to two feathers in two
pieces of mid-Cretaceous (100 Ma) amber from Myanmar, and states that
evidence “strongly suggest[s] that Mesophthirus is
ectoparasitic”. The feathers are presumably from stem-group, feathered
avialan dinosaurs. Despite the abundance of feathers in Burmese amber and even the rare occurrence of nestling pennaraptorans, ticks have been the only ectoparasites found thus far in Burmese amber.
The authors left Mesophthirus as incertae sedis
to any insect order because of what they proposed as an unusual
combination of features. We independently concluded that these insects
are actually early instar nymphal scale insects (order Hemiptera;
suborder Sternorrhyncha; superfamily Coccoidea). As such, Mesophthirus could not have been parasitic; their proximity to feathers is a fossilized coincidence unrelated to diet.