Scott Hartman
← Research

Physiological modeling

Linked microclimate and heat-balance models that ask where extinct animals could actually live.

Daily body-temperature curves for Varanus and Coelophysis in hot and cold microclimates
Daily body-temperature curves for Varanus and an uninsulated Coelophysis in hot and cold microclimates (Lovelace et al. 2020, fig. 11).

In 2012 I joined Warren Porter, David Lovelace, and Paul Mathewson to apply Niche Mapper, a mechanistic model of the heat and water exchange between an animal and its environment, to extinct vertebrates.

Niche Mapper pairs a microclimate model, which rebuilds the hour-by-hour temperatures, wind, humidity, and radiation an animal would experience, with an animal model built from body size and shape, posture, insulation, and metabolism. Rather than asking whether a dinosaur was “warm-blooded,” it lets us ask which combinations of metabolic rate, insulation, and body size could survive in a given environment, and where.

Schematic of a Niche Mapper simulation: solar and thermal radiation, wind and temperature profiles, and burrow and shade microhabitats around a model animal
Schematic of a Niche Mapper simulation: the microclimate model supplies radiation, wind, and temperature profiles above and below ground.

Our first test case, Modeling Dragons (Lovelace et al. 2020), examined Late Triassic dinosaurs from the Chinle Formation. It found support for elevated, ratite-like metabolic rates, and suggested that large prosauropods would have been heat-stressed in open, hot environments. Follow-up work extended the approach to predict the biogeographic distribution of Late Triassic terrestrial amniotes (Hartman et al. 2022), and my dissertation applied it to macroevolution, thermal ecology, and extinction in Mesozoic tetrapods.

Papers

  1. 2022

    Mechanistic Thermal Modeling of Late Triassic Terrestrial Amniotes Predicts Biogeographic Distribution

    Hartman SA, Lovelace DM, Linzmeier BJ, Mathewson PD, Porter WP

    Diversity 14(11): 97310.3390/d14110973

  2. 2020

    Modeling Dragons: using linked mechanistic physiological and microclimate models to explore environmental, physiological, and morphological constraints on the early evolution of dinosaurs

    Lovelace DM, Hartman SA, Mathewson PD, Linzmeier BJ, Porter WP

    PLOS ONE 15(5): e022387210.1371/journal.pone.0223872

  3. 2020

    Macroevolution, thermal ecology and extinction in terrestrial Mesozoic tetrapods

    Hartman SA

    PhD dissertation, University of Wisconsin–Madison

Conference abstracts & talks

  1. 2021

    Thermal ecology drove survivorship patterns of terrestrial vertebrates across the end-Triassic extinction

    Hartman SA

    Triassic Vertebrate Paleontology Meetup

  2. 2016

    Mechanistic physiological modelling predicts geographic distribution of Late Triassic tetrapods

    Hartman SA

    Society of Vertebrate Paleontology 76th Annual Meeting

  3. 2015

    Using ecological modelling to quantify thermal constraints on two Late Triassic dinosaurs

    Hartman SA, Lovelace DM, Linzmeier BJ

    Society of Vertebrate Paleontology 75th Annual Meeting