A new holomorphic specimen of the rare holocephalian fish, Chimaeropsis paradoxa, from the Late Jurassic Plattenkalk of Germany

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SVP 2018
A new holomorphic specimen of the rare holocephalian fish, Chimaeropsis paradoxa, from the
Late Jurassic Plattenkalk of Germany
Bruce Lauer1, Evgeny V. Popov2, 3, Christopher J. Duffin4, David J. Ward4and René Lauer1
Chimaeropsis paradoxa is amyriacanthoid
chimaeriform fish (Family Chimaeropsidae) from the
Late Jurassic Plattenkalk of Eichstätt in Bavaria,
described from asingle specimen by Karl Alfred von
Zittel in 1887.The material was never adequately
figured, and the unique holotype was destroyed in
World War II. A holomorphic specimen of the fish,
slightly smaller than the holotype, was recently
obtained by the Lauer Foundation for Paleontology,
Science and Education (LF 2317).
The specimen, comprising part and counterpart, is a
730 mm long male with ashort, bulky head lacking a
long rostrum, with adorsally curved trunk (post-
mortem position) containing representations of the
musculature and valvular intestine, scapulocoracoid,
homocercal tail, and poorly preserved pelvic fins with
pelvic claspers.
The head preserves the neurocranium and associated
right mandible, apartially preserved lateral line
system, 4pairs of tuberculated dermal plates (only 3
pairs were described in the holotype) and atypically
myriacanthoid dentition comprising paired anterior
and posterior upper tooth plates, mandibular tooth
plates and an unpaired lower symphyseal tooth plate
exposed in right lateral view.
The squamation consists of conical, star-like scales of
various sizes, depending on their location on the body,
with aseries of enlarged scales in the region of the
frontal midline.
The dorsal fin spine (145 mm long) is of myriacanthid
organization with tuberculate walls and an anterior
row of irregular, distally-directed denticles;no
posterior denticle rows are visible.
Details from the new specimen allow revised
diagnoses to be given for the type species, the genus
and the family.
Funding:Support of EAVP was from the Russian
Federation for Basic Research, grant 18-05 01045.
Abbreviations:
cfs –caudal fin, supracaudaal lobe;cfh –caudal fin,
hypocaudaal lobe;dfs -dorsal fin spine;dpl -paired
tuberculated dermal plates;efs -enlarged frontal
scales;fc –frontal clasper;lsc –lateral sensory
canal;mym -myotomic musculature;nc –
neurocranium;or –orbit;pc -pelvic claspers;rm -
right mandibular tooth plate;sc –scapulocoracoid;
stp -lower symphyseal tooth plate;uap -right upper
anterior tooth plate;upp -right upper posterior tooth
plate;vi -valvular intestine.
1Lauer Foundation for Paleontology, Science and Education, Wheaton, Illinois, USA.
2Department of Palaeontology, Saratov State University, Saratov, 410012, Russia.
Chris Duffin
cduffin@blueyonder.co.uk David J. Ward
david@fossil.ws
René Lauer
Rene@lauerfoundationpse.org Bruce Lauer
Bruce@lauerfoundationpse.org
Evgeny Popov
elasmodus74@gmail.com
3Institute of Geology and Petroleum Technology, Kazan Federal University, Kremlevskaya Str. 4/5, 420008 Kazan, Russia.
4Department of Earth Sciences, The Natural History Museum, London, SW7 5BD, U.K.
Star-like scales in UV light (enlarged from left
picture).Star-like scales covering neurocranium
(enlarged, scale in mm).
Star-like scales in midline frontal region (enlarged,
scale in mm).
Valvular intestine, myotomic musculature and part of the
pelvic fin in UV light (counterpart slab, reversed).