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Phylogenetic analysis of Paleozoic limbed vertebrates + Crocodyliform footprints from Morocco



Ben Creisler
bcreisler@gmail.com

A number of recent non-dino papers in open access:


David Marjanović & Michel Laurin (2015)
Reevaluation of the largest published morphological data matrix for
phylogenetic analysis of Paleozoic limbed vertebrates.
PeerJ PrePrints 3:e1995
doi: https://doi.org/10.7287/peerj.preprints.1596v1
https://peerj.com/preprints/1596/

The largest data matrix for phylogeny of early limbed vertebrates
(Ruta M, Coates MI. 2007. J. Syst. Palaeont. 5:69–122) has supported
controversial hypotheses; e.g., it has recovered Seymouriamorpha,
Diadectomorpha and (in some trees) Caudata as paraphyletic and found
the “temnospondyl hypothesis” on the origin of Lissamphibia (TH) to be
one step more parsimonious than the “lepospondyl hypothesis” (LH).
Scrutiny of the matrix reveals thousands of suboptimal scores (many
clearly due to typographic and similar errors) as well as logically
linked (redundant) characters, characters with only one described
state, and even cases where taxa were scored after presumed relatives.
Moreover, all characters – even obviously continuous ones – were
unordered, effects of ontogeny were not sufficiently taken into
account, and the authors mostly excluded data published after 2001,
even their own. Our revised version – we document and justify all
changes – yields much longer trees with a different topology, e.g.
monophyletic Caudata, Diadectomorpha and (sometimes) Seymouriamorpha,
Ichthyostega more rootward than Acanthostega, Anthracosauria more
rootward than Temnospondyli, and the LH, which is 10 steps more
parsimonious than the TH and 15 more than the “polyphyly hypothesis”
(PH). Bootstrap values, though, are low, and few of the topologies are
statistically distinguishable. For another set of analyses, we added
48 OTUs to the original 102. This destabilizes parts of the tree, e.g.
the relationships of Anthracosauria and Temnospondyli. However, many
of the added taxa have a fully resolved position or nearly so; this
concerns the well-known Chroniosaurus (sister to a clade containing
Solenodonsaurus, Seymouriamorpha, Diadectomorpha, Amniota and
Amphibia), but also isolated lower-jaw material from the Devonian and
Carboniferous. Despite the addition of Gerobatrachus, Micropholis and
Tungussogyrinus and the extremely peramorphic salamander Chelotriton,
the difference between LH and TH only shrinks to 9 steps, that between
LH and PH to 13 steps. The “lepospondyl” Brachydectes is neither found
as sister to Lissamphibia nor in the “microsaur” grade. Bootstrap
values plummet, though, and all three hypotheses become statistically
indistinguishable at p = 0.05. We then duplicated all analyses after
coding all losses of bones as irreversible. Anthracosauria is then
consistently placed more rootward than Temnospondyli; given the
original taxon sample, the LH is 12 steps shorter than the
“temnospondyl hypothesis” and 17 steps shorter than the PH, while the
expanded taxon sample makes the LH 10 steps shorter than the TH and
only 12 steps shorter than the PH. More robust results could likely be
obtained by adding the many characters used in other analyses or
discussed in the literature. We discuss phylogeny, approaches to
coding, and certain character complexes, in particular the supposed
middle ear of temnospondyls.

==

M. Hadri, M. Boutakiout, F. Gómez and F. Pérez-Lorente (2015)
Crocodyliform footprints from “les couches rouges” of the Middle
Jurassic of Msemrir, High Atlas, Morocco / Icnitas cocodriliformes de
las “couches rouges” del Jurásico Medio de Msemrir, Alto Atlas,
Marruecos.
Geogaceta 58: 39-42
http://www.sociedadgeologica.es/archivos/geogacetas/geo58/geo58pag39-42.pdf

Two Crocodyliform footprints from "les couches rouges" of the Middle
Jurassic of the High Atlas are described.We highlight it for its
scarcity in the global record. Footprints cannot be compared with
other known ichnogenus. The pes print is incomplete.We assume that it
is a continental crocodyliform because the footprints are in fluvial
deposits. Finally there follows, although with wide margins of
uncertainty, the size that we assume for the trackmaker.

===

A paper that may be of interest; posted online in advance some months
back, but now officially published. The pdf is free:


Lothar Herbert Vallon, Andrew Kinney Rindsberg & Richard Granville
Bromley (2016)
An updated classification of animal behaviour preserved in substrates.
Geodinamica Acta 28(1-2): 5-20
DOI:10.1080/09853111.2015.1065306
http://www.tandfonline.com/doi/full/10.1080/09853111.2015.1065306


During the last few decades, many new ethological categories for trace
fossils have been proposed in addition to the original five given by
Seilacher. In this article, we review these new groups and present a
version of the scheme of fossil animal behaviour originally published
by Bromley updated with regard to modern ethological concepts,
especially those of Tinbergen. Because some behaviours are more common
in certain environments than others, they are useful in
palaeoecological reconstructions, forming the original basis of the
ichnofacies concept. To simplify, we summarise some ethological
categories as previously done by others. However, the tracemaker’s
behaviour in some cases is so distinctive that subcategories should be
employed, especially in ecological interpretations of certain
environments where a special behaviour may be dominant.