Fossils and Las Hoyas

The unique fossils of this site represent the ecological structure of a Lower Cretaceous wetland  (Barremian, 124-129 My) with unprecedented biological detail. There are myriads of organisms (plants and animals), including the earliest angiosperms along with ferns and conifers, insects and other arthropods--aquatic and terrestrial--, thousands of fishes and tiny sharks, large and small reptiles, predatory and herbivore dinosaurs, early birds, and mammals. The fidelity to the diversity of a modern ecosystem is so high that we feel as looking to the real physiongnomy of a long-extinct ecosystem. In fact, the  degree of preservation of soft tissue in the fossils further enhances this picture by enabling access to structural detail of hard (bone) and soft (skin) tissues. For instance, we can see bone layers at microscopic level, but also a hair's microstructure inside its skin pore. We have a new project in which, added to the historical search for new fossils and the experimental setting to understand their formation (taphonomy), we are taking the first steps to understand the complex ecological structure of the wetland using networks.

Take a look at the Las Hoyas book

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Spinolestes xenarthrosus

(Martin et al., 2015)

Isolated feathers of Las Hoyas

(Marugán-Lobón and Vullo, 2011)

Fossil skulls, dinosaurs and avian evolution

The emergence of an avian skull encompassed quite complex evolutionary processes. A great part of my research has been devoted to study avian skull evolution at macroevolutionary scales using shape analysis (Geometric Morphometrics). Much of the focus has been both in skull and brain organization, the assessment of their interplay, and developing hypotheses about how development might be underlying these macroevolutionary patterns.

3D landmarks in the avian brain

(Marugán-Lobón et al., 2016)

The evolution of the avian skull

(Buhllar et al., 2012)

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Mesozoic Birds and the evolution of avian life histories

Confuciusornis sanctus

Confuciusornis is the most abundant of all the fossil birds unearthed from the Lower Cretaceous Jehol biota in Liaoning Province (China). Actually, it is estimated that nearly a thousand of specimens have been unearthed since its discovery in the late 90's. Using large samples of these fossils, Dr. Chiape at the Dinosaur Institute of the NHM (Los Angeles, CA) and I, have unveiled intriguing features of the life history of this primitive birds.  For instance, we showed that this bird's growth was prolongued, entailing that populations encompassed individuals of multiple sizes, quite unlike modern birds. We were able to determine that the long tail feathers of several specimens were secondary sexual characteristics, and we are now studying its unique beak.

Connectivity structure of the human skull

(Esteve-Altava et al., 2013)

Fossils, macroevolution and complexity

 

Together with my dear colleagues at the Theoretical Biology lab at the University of Valencia (and at the Institute de Biología Evolutiva, Barcelona) we devised the early steps of the AnNA (Anatomical Netowrk Analysis), a methodological and conceptual framework to study the evolution of morphology  via complex network analysis (i.e., graphs)

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Human skull bone connectivity graph

(Esteve-Altava et al., 2013)

Biological form and shape analysis

 

Using Geometric Morphometrics, we've studied multiple aspects of the evolution of organisms, such as the skull of birds. 

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Morphospace of raptor skull shape evolution

(Brght et al., 2016)

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Complex interations between ecology, shape variation and biomechanics shaping the avian beak

(Navalón et al., 2018)

The evolutionary integratiof the beak and the cranium in finches

(Navalón et al., 2019)

Multivariate growth of the chicken skull

(Marugán-Lobón et al., 2014)

We've also developed a new tool to study articulated structures using Procrustes Methods, which we called the One Dimensional Procrustes approach (OPA). We succesfully demonstrated its potential to address the evolution of the maniraptoran hand.

Nebreda et al, (2020)

And exploited the potential of such methods to explore features of shape variation in unexplored settings, such as dinosaur trackways  (Costa et al., 2019)