Neil Brocklehurst
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    • Pelycosaur Phylogeny
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  • Home
  • Research
  • Methods
    • RAC Beta Diversity
    • Defining Bioregions
    • Forbes' Metric
    • Biogeography Simulation
    • Diversity Simulation
    • Tooth-row Evolution Simulation
    • Pelycosaur Phylogeny
    • Analysis of Constraint
  • Publications
  • Contact

Phylogenetic analysis of Pelycosaurian-Grade Synapsids

Pelycosaurs are a grade of six families that lie at the very base of the mammalian stem. Yes, these guys include our ancestors. Also there are some exciting forms like the macro-predator Dimetrodon (left), earliest herbivore Edaphosaurus (middle) and pinhead ​Cotylorhynchus​ (right).
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In working out the phylogeny of pelycosaurs, researchers have, for the most part, been building iterations of one study: Roger Benson's 2012 paper in Systematic Palaeontology. This was at the time by far and away the most comprehensive evolutionary tree of the six families, both in terms of species and morphological characters included. Over the subsequent 8 years, this analysis has been expanded, modified and refined (by, amongst many others, myself), and forms the basis of much of our understanding of the earliest evolution of our lineage. 
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What I wanted to do here was collate all the morphological data from all the subsequent analyses into one place. The thing is, the research has not followed a linear trajectory. Each study builds on the most recent one out at the time of starting the research but, as research is a slow process and in the last couple of years there has been a slew of pelycosaurs added to the available datasets by different working groups, we get a branching tree of trees. No study contains all the available data. 
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The complete character list is also not currently available in any single publication. Sure, you can piece together all the additions and state modifications if you go through the supplements of three different papers, but let's face it, no one wants to do that.

So here i'm uploading the most up-to-date version of the character list with the sources of each character. I've also created a matrix of all the available taxa that have been scored into the matrix. This was done by taking the Maddin et al (2020) matrix, and adding to it Martensius (as scored by Berman et al. 2020), Alierasaurus (same source), M. efremovi (as scored by Maho et al. 2019) and updating Echinerpeton (as scored by Mann & Paterson 2019). All scores are as published in the peer-reviewed paper; I wanted the matrix to represent all the peer-reviewed data. What that did mean was that M. efremovi has not been assessed for character 245, as this was added in an iteration later than the one Maho et al. used as their source.

So all the available data is here, feel free to use it:
Character List
Matrix (Nexus File)

And references:
Benson, R. B. (2012). Interrelationships of basal synapsids: cranial and postcranial morphological partitions suggest different topologies. Journal of Systematic Palaeontology, 10(4), 601-624.

Berman, D. S., Maddin, H. C., Henrici, A. C., Sumida, S. S., Scott, D., & Reisz, R. R. (2020). New Primitive Caseid (Synapsida, Caseasauria) from the Early Permian of Germany.
Annals of Carnegie Museum, 86(1), 43-75.

Brocklehurst, N., & Fröbisch, J. (2017). A re-examination of the enigmatic Russian tetrapod Phreatophasma aenigmaticum and its evolutionary implications.
Fossil Record, 20(1), 87-93.

Brocklehurst, N., & Fröbisch, J. (2018). A reexamination of Milosaurus mccordi, and the evolution of large body size in Carboniferous synapsids.
Journal of Vertebrate Paleontology, 38(5), e1508026.

Brocklehurst, N., Reisz, R. R., Fernandez, V., & Fröbisch, J. (2016). A re-description of ‘Mycterosaurus’ smithae, an Early Permian eothyridid, and its impact on the phylogeny of pelycosaurian-grade synapsids.
PLoS One, 11(6).

Maho, S., Gee, B. M., & Reisz, R. R. (2019). A new varanopid synapsid from the early Permian of Oklahoma and the evolutionary stasis in this clade.
Royal Society Open Science, 6(10), 191297.

Maddin, H. C., Mann, A., & Hebert, B. (2020). Varanopid from the Carboniferous of Nova Scotia reveals evidence of parental care in amniotes.
Nature Ecology & Evolution, 4(1), 50-56.

Mann, A., & Paterson, R. S. (2020). Cranial osteology and systematics of the enigmatic early ‘sail-backed’synapsid Echinerpeton intermedium Reisz, 1972, and a review of the earliest ‘pelycosaurs’.
Journal of Systematic Palaeontology, 18(6), 529-539.

Reisz, R. R., & Fröbisch, J. (2014). The oldest caseid synapsid from the Late Pennsylvanian of Kansas, and the evolution of herbivory in terrestrial vertebrates.
PloS one, 9(4).
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