As the abstract explains, because Haeckel's biogenetic law has been used by developmental biologists to develop and explore the idea of a conserved body plan, the authors naturally examined Haeckel's strongest evidence -- his drawings. In concluding that these drawings are inaccurate, they also conclude that Haeckel's conception of the biogenetic law is also flawed, and by extension so is the concept of the conserved body plan. However, their examination of Haeckel is secondary to their overall purpose, and they do not label Haeckel a fraud.
[It should be noted that even these scientists acknowledge that Haeckel's biogenetic law has been used as a basis for modern ontogenetic theory. It should also be pointed out that there are many developmental biologists who disagree that there is no conserved body plan; I will present the opinions of two in my upcoming essay.]
However, so many anti-evolutionists and anti-Haeckel people have tried to claim that Richardson _et al._ did claim that Haeckel was a fraud that the authors wrote a letter to _Science_ debunking that claim. I will reproduce that letter unedited in my upcoming essay, but while they repeat their criticism that Haeckel was inaccurate, they do not label him a fraud. They also make the claim that despite the inaccuracy of his drawings, Haeckel's conclusions, _based on those very same drawings_, regarding the evolutionary relationship between ontogeny and phylogeny are correct. In other words, they say that Haeckel's biogenetic law -- ontogeny recapitulates phylogeny -- is true.
Since it is logically impossible for someone to tell the truth while deliberately trying to deceive people, I think this is adequate evidence that Haeckel was no fraud. This is also adequate evidence that, despite the claims of some on this group, the biogenetic law is still viable and that it does serve as the basis for modern developmental biology. I hope to present more evidence in my upcoming essay.
Kevin L. O'Brien