A major area of my current research involves the study of the influence of natural selection in shaping the design of the mammalian skull. Specifically, I am trying to quantify how different lineages of carnivores are adapted to different feeding behaviours.
This approach allows me to explore homoplastic patterns as a result of both adaptation and constraint. By using geometric morphometrics and phylogenetic comparative methods, I interpret similarities between the skulls of distantly related taxa as adaptations towards similar diets from an ecomorphological point of view. Up to date, I have identified skull shape adaptations towards hypercarnivory (Figueirido et al 2011: Paleobiology 37: 490), herbivory (Figueirido et al 2010: J Biol Evol 23, 2579), and durophagy (Figueirido et al 2013: Evolution 67, 1975) in carnivores. Currently, I am also working in exploring homoplastic patterns in the carnivoran skull towards insectivory, a very interesting diet because the soft nature of the items consumed entails a very different "toolkit" compared to other, more functionally-demanding diets such as hypercarnivory or durophagy.
In collaboration with my colleague Zhijie Jack Tseng from the American Museum of Natural History (New York) we are currently assessing these homoplastic patterns of skull shape towards different feeding behaviours by 3D biomechanical modelling, using Finite Element Analysis (FEA), Figueirido et al. 2014:Biolletters10,20140196).
Although there is still a lot of work to do on this topic, my main goal is to extend all the insights obtained from this research to fossil mammals in order to infer quantitatively the feeding behaviour of extinct taxa (e.g., Figueirido et al 2009: J Zool 277, 70; Figueirido et al. 2010: J Vert Palaeo 30, 262; Figueirido & Soibelzon 2010: Lethaia 43, 209).
Together with my Ph.D. student Alex Pérez-Ramos, we are exploring the internal skull structures –mainly the sinuses and brain– to provide distinct but complimentary information on the evolutionary history of the mammalian skull relative to the information obtained from the shape of the external surface.
I am specifically exploring how the shape of the internal skull in mammals responds to those patterns of homoplasy towards different diets: Is phylogenetic inheritance involved in shaping the internal structures in a similar way than the external surface of the skull? Could we recognize the same patterns of homoplasy towards having different diets from the internal structures as we do in relation to the external surface, or are other variables involved? Do internal skull structures govern the shape of the external surface or vice versa? I am currently trying to answer this kind of questions by using CT scans, geometric morphometrics, and phylogenetic comparative methods to finally gain knowledge on the mammalian skull evolutionary history.
Another potential aspect that involves the study of internal skull structures is the inference of different visual parameters from the morphology and orientation of the orbits (eye sockets). My Ph.D. student Alejandro Pérez-Ramos, my undergraduate student Carlos Casares and I are exploring, by means of three-dimensional landmarks, the inference of visual parameters from dry skulls.