Graeme T. Lloyd - Contributions, Data, Methods & Library

Me (left) in the Drakensburg, South Africa<br>Photo © E. Lloyd, 2004

Welcome to my web site. I am currently a post-doctoral research assistant at the University of Oxford (Oxford, UK). Below is a brief summary of some of my research interests. This site (like so many others) is a work in progress, but I hope one day it will be a useful resource for various palaeontological, phylogenetic and evolutionary methods and data.

Triassic Tetrapod Macroevolution
My Masters thesis involved the compilation of a genus-level tetrapod database tallying first and last appearances (i.e. range-through diversity), body size estimates, habitat, diet and geographic range to assess selectivity of Late Triassic events. Preliminary results of this work were presented at SVP, SVPCA and PalAss. Plans to publish this work "as is" have been shelved, but this project represents the seed of some collaborative efforts currently underway and planned for the future. More recently I have been involved in a related project looking at morphological disparity and rates of character evolution in the two main archosaur lineages through the same time period. This has resulted in publications in Science and Biology Letters (see the contributions page).

Character Acquisition Through Geological Time
The central theme of my PhD research concerned quantitatively exploring the temporal sequence of acquired morphological characters using cladistic datasets. My methodology is an updating of classic work by Stanley Westoll, who used a (pre-Hennigian) character-taxon matrix to demonstrate that modern lungfish acquired most of their modern character suite in the Middle Devonian to Early Carboniferous, with very little change recorded in the interim. My work explored whether this pattern is specific to so-called 'living fossils', or whether it was a more widespread evolutionary phenomenon. Preliminary results of my enquiries have been presented at IPC, PalAss and a NIEeS workshop and a manuscript is in preparation.

Towards a Tetrapod Supertree
It has been argued that nothing in evolution makes sense except in the light of phylogeny, but truly large phylogenies, particularly of fossil taxa, are immensely time-consuming to produce. Tetrapods in particular benefit from phylogenetic analysis, e.g. to fill in missing data (ghost ranges) and are comparatively well understood phylogenetically. Supertrees - the combination of multiple subtrees with overlapping taxon sets into a single larger tree - are perhaps our best way of attaining large phylogenies. I have played a minor role in producing a supertree of temnospondyls (the most diverse group of early tetrapods) and have led a collaborative effort to update the dinosaur supertree first produced by Davide Pisani and others in 2002. Both studies have been published (see the contributions page) and the dinosaur supertree has been presented at SVP, SVPCA and a poster will appear at this year's PalAss. The dinosaur tree, including details of its construction are available on the Department of Earth Science's supertree page.

Proteomics and Biologic Complexity
The complexity of any system is best defined by the number of interactions between it's parts. Understanding such networks in organisms is the goal of geneticists, but results can only be attained through the concentrated efforts of numerous workers over several years. An alternative approach is simply to look at the number of different components to a system, perhaps the best example of which is cell types (first suggested by Jim Valentine and colleagues). I am part of a collaborative effort to look at proteins in a similar way using a database which annotates genomes by the protein structural domains that they encode. Initial results have been presented at the BA Festival of Science and PalAss.


	Research \| Contributions \| Matrices \| Methods \| Library \| Photos \| Links

	Me (left) in the Drakensburg, South Africa (Photo © E. Lloyd, 2004) Welcome to my web site. I am currently a post-doctoral research assistant at the University of Oxford (Oxford, UK). Below is a brief summary of some of my research interests. This site (like so many others) is a work in progress, but I hope one day it will be a useful resource for various palaeontological, phylogenetic and evolutionary methods and data. Triassic Tetrapod Macroevolution My Masters thesis involved the compilation of a genus-level tetrapod database tallying first and last appearances (i.e. range-through diversity), body size estimates, habitat, diet and geographic range to assess selectivity of Late Triassic events. Preliminary results of this work were presented at SVP, SVPCA and PalAss. Plans to publish this work "as is" have been shelved, but this project represents the seed of some collaborative efforts currently underway and planned for the future. More recently I have been involved in a related project looking at morphological disparity and rates of character evolution in the two main archosaur lineages through the same time period. This has resulted in publications in Science and Biology Letters (see the contributions page). Character Acquisition Through Geological Time The central theme of my PhD research concerned quantitatively exploring the temporal sequence of acquired morphological characters using cladistic datasets. My methodology is an updating of classic work by Stanley Westoll, who used a (pre-Hennigian) character-taxon matrix to demonstrate that modern lungfish acquired most of their modern character suite in the Middle Devonian to Early Carboniferous, with very little change recorded in the interim. My work explored whether this pattern is specific to so-called 'living fossils', or whether it was a more widespread evolutionary phenomenon. Preliminary results of my enquiries have been presented at IPC, PalAss and a NIEeS workshop and a manuscript is in preparation. Towards a Tetrapod Supertree It has been argued that nothing in evolution makes sense except in the light of phylogeny, but truly large phylogenies, particularly of fossil taxa, are immensely time-consuming to produce. Tetrapods in particular benefit from phylogenetic analysis, e.g. to fill in missing data (ghost ranges) and are comparatively well understood phylogenetically. Supertrees - the combination of multiple subtrees with overlapping taxon sets into a single larger tree - are perhaps our best way of attaining large phylogenies. I have played a minor role in producing a supertree of temnospondyls (the most diverse group of early tetrapods) and have led a collaborative effort to update the dinosaur supertree first produced by Davide Pisani and others in 2002. Both studies have been published (see the contributions page) and the dinosaur supertree has been presented at SVP, SVPCA and a poster will appear at this year's PalAss. The dinosaur tree, including details of its construction are available on the Department of Earth Science's supertree page. Proteomics and Biologic Complexity The complexity of any system is best defined by the number of interactions between it's parts. Understanding such networks in organisms is the goal of geneticists, but results can only be attained through the concentrated efforts of numerous workers over several years. An alternative approach is simply to look at the number of different components to a system, perhaps the best example of which is cell types (first suggested by Jim Valentine and colleagues). I am part of a collaborative effort to look at proteins in a similar way using a database which annotates genomes by the protein structural domains that they encode. Initial results have been presented at the BA Festival of Science and PalAss.
Last updated 7th November 2008.