Introduction to Evolutionary Teratology, with an Application to the Forelimbs of Tyrannosauridae and Carnotaurinae (Dinosauria: Theropoda)

Dinosaurs, Chameleons, Humans, and Evo‐Devo Path: Linking Étienne Geoffroy's Teratology, Waddington's Homeorhesis, Alberch's Logic of “Monsters,” and Goldschmidt Hopeful “Monsters”

“…Although the vast majority of such mutations would be disastrous (“monsters”), there may be one macromutation leading to the adaptation of an organism to a new way of life—a hopeful “monster.” Therefore, macroevolution would occur with the rare success of hopeful “monsters” rather than by an accumulation of small changes in populations. However, as explained by Guinard, this notion is often misinterpreted as the achievement of “perfection” in a jump (extreme saltationism), and Goldschmidt is often used as a “straw‐man.” The examples provided by Guinard, which will be described in section Macroevolutionary and Paleontological Works as Case Studies, emphasize that pathological features of one taxon (e.g., humans) are often seen as the normal phenotype of another taxon (e.g., dinosaurs), nevertheless support some of Goldschmidt's ideas and thus contributed to the resurgence of ideas defended by Étienne and Isidore Geoffroy Saint‐Hilaire, more than 150 years ago: “monstrosity is no longer a blind disorder but another order, also regular and subject to laws” (Guinard, : 21).…”

“…Indeed, digit IV of Ceratosauria is not complete: it is a previous teratological feature persisting along the lineage and therefore that must be repeated for each taxon. See Guinard () for more details.…”

“…More recently, Guinard () proposed the concept of evolutionary teratology based on the notion that current and extinct wild types of certain taxa arose through deviations of “normal” development that could be seen as developmental anomalies. For him those deviations are not necessarily drastic; that is why he made a distinction between his conception and some of the notions related with Goldschmidt's hopeful “monsters.” Goldschmidt () introduced the concept of developmental macromutations—that is, mutations of important developmental genes that can produce significant phenotypic effects—to explain macroevolution.…”

“…Surprisingly, in the context of the emphasis of developmental biology (“devo”) within evo‐devo (evolutionary developmental biology) since the rise of this field in the 1980s, few authors have attempted to combine the knowledge obtained from the study of model organisms and from human medicine with data available on comparative anatomy and evolutionary biology to investigate the links between development, pathology, and macroevolution (Diogo, ). Fortunately, this scenario seems to be slowly changing, with a renewed interest in evolutionary developmental pathology (evo‐devo‐path) in the past few decades, as evidenced by Gunter Wagner's idea to publish this special, and very timely, issue on “Developmental Evolution in Biomedical Research.” Because the three of us have recently been involved, independently, in works related in some way or another with evolution and developmental anomalies (Diaz and Trainor, ; Guinard, , ; Diogo et al., ; ), we decided to combine our different perspectives and backgrounds in the present contribution for this special issue.…”

Applying evolutionary genetics to developmental toxicology and risk assessment

“…In the course of evolution, a similar developmental outcome (forelimb atrophy) is stabilized to better adapt to ecological niches in (E) two-toed amphiuma ( Amphiuma means ), a native species of salamanders in North Carolina; (F) flightless birds, such as the dodos ( Raphus cucullatus ); and (G) the family Tyrannosauridae and subfamily Carnotaurinae of theropod dinosaurs, such as Tyrannosaurus rex (Guinard 2015). The images were used with permission of (A–D) the American Association for the Advancement of Science (Ito et al 2010), and (F) Michael Hanson (Yale University); and taken in (E) the North Carolina Museum of Natural Sciences, Raleigh, NC, and (G) the National Museum of Natural History, Smithsonian Institution, Washington, D.C.…”