Dataset to: Kampouridis et al. (2025) "Unique pathological phalangeal fusion in the chalicothere subfamily Chalicotheriinae and the interphalangeal immobilization in chalicotheres"

<p>MicroCT scan of a phalange of Chalicotheriidae.</p><p>Chalicotheres are bizarre
extinct herbivore mammals closely related to today’s rhinoceroses, tapirs
and horses. Chalicotheriidae includes two subfamilies, the
Chalicotheriinae and the Schizotheriinae. Some members of the
schizotheriines form a duplex bone by fusing the proximal and the medial
phalanges of the second digit of the hand. Here, we report the only known
fused set of proximal and medial phalanges in a specimen of the subfamily
Chalicotheriinae from the Late Miocene of Höwenegg in Germany. This specimen
has been the center of some confusion regarding its identity and the
nature of the fusion. In our study, we conduct a detailed comparison to
chalicotheriines and schizotheriines, identifying the specimen as a
chalicotheriine. We additionally acquired CT-scans of this specimen and
two schizotheriines, <i>Metaschizotherium fraasi</i> from the Middle
Miocene of Steinheim (Germany) and <i>Ancylotherium pentelicum</i> from
the Late Miocene of Pikermi (Greece), to compare the internal structure of
the fused phalanges, which revealed great differences between the fusion
in the Höwenegg specimen and in schizotheriines. Furthermore, we found
that both subfamilies show a trend towards immobilizing their digits,
expressed in different ways, with chalicotheriines forming a notched-joint
between the phalanges in some digits that hinders their movement and
schizotheriines regularly fusing the phalanges.</p>