10.5061/DRYAD.RFJ6Q576V
Giles, Sam
0000-0001-9267-4392
University of Birmingham
University of Birmingham
Mondéjar-Fernández, Jorge
0000-0003-0853-929X
National Museum of Natural History
Friedman, Matt
University of Michigan–Ann Arbor
Redescription of the cranial skeleton of the Early Devonian (Emsian)
sarcopterygian Durialepis edentatus Otto, 2007 (Dipnomorpha;
Porolepiformes)
Dryad
dataset
2020
computed tomography
Sarcopterygii
stem-lungfish
cranial skeleton
Natural Environment Research Council
https://ror.org/02b5d8509
NE/J500045/1
Royal Society
https://ror.org/03wnrjx87
2020-04-08T00:00:00Z
2020-04-08T00:00:00Z
en
https://doi.org/10.1002/spp2.1315
7923993087 bytes
4
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Porolepiforms represent a clade of Devonian stem lungfishes, divided into
the cosmine-bearing and likely paraphyletic ‘Porolepidae’ (e.g.,
Porolepis, Heimenia) and the cosmine-free and stratigraphically younger
Holoptychiidae (e.g., Holoptychius, Glyptolepis, Laccognathus). Data on
the dermoskeleton are available for both groups, but are more limited for
‘porolepids’. Here we present new information on the ‘porolepid’
Durialepis edentatus from the Emsian (Early Devonian) of Germany based on
micro-CT scanning. The material comprises an articulated skull of a single
three-dimensionally preserved individual. The arrangement of the
cheekbones of Durialepis edentatus recalls that of Porolepis brevis, with
the occurrence of two subsidiary squamosals. However, the
parieto-ethmoidal and postparietal shields are roughly equal in size, a
condition similar to that of Glyptolepis groenlandica and intermediate
between Porolepis brevis and holoptychiids. A large parasymphysial tooth
plate displays five tooth rows with three large tusks in the median row,
another intermediate arrangement between the primitive condition of
Porolepis sp. (eight rows) and holoptychiids (five or fewer rows).
Remarkably among porolepiforms, this dental plate is perfectly
symmetrical. Despite the occurrence of cosmine and rhombic scales, the
combination of traits displayed in Durialepis deviates from Porolepis in
several ways, reflecting features shared with holoptychiids to the
exclusion of other ‘porolepids’. Durialepis edentatus is thus a key
addition to our knowledge of ‘porolepid’ anatomy. Because Durialepis
edentatus preserves much of the cranial and postcranial skeleton in a
single individual, it represents a suitable early dipnomorph
representative for inclusion in phylogenetic analyses on sarcopterygians
and early osteichthyans.
The specimen was scanned using a Nikon Metrology HMX ST 225 CT scanner at
the Natural History Museum, London, with the following settings: 205 kV;
160 µa; 6284 projections; 0.5 mm copper filter; with a resulting voxel
size of 85.7 µm. Data were segmented manually in Mimics Innovation Suite
V.18.0 (http://biomedical.materialise.com/mimics; Materialise, Leuven,
Belgium) and resultant PLY files exported into and rendered in Blender
V.2.77a (http://www.blender.org; Blender Institute, Amsterdam,
Netherlands). The following data are made available: raw TIFF stack
(converted in ImageJ from .vol file) and associated metadata file; Mimics
file containing loaded dataset and segmentation; 3D PLY files exported
from Mimics.