TAXONOMIC NOTES ON MEGAPNOSAURUS AND 'SYNTARSUS' (THEROPODA: COELOPHYSIDAE)

Abstract

The genus name Syntarsus Raath 1969 is preoccupied by the genus Syntarsus Fairmaire 1869. The replacement name Megapnosaurus Ivie et al. 2001 was proposed but its usage is inconsistent due to both controversy on the validity of the nomenclatural act proposing Megapnosaurus and possible synonymy between it and Coelophysis Cope 1889. The nomenclatural act proposing Megapnosaurus is found to be valid, while synonymy between the genera Megapnosaurus and Coelophysis is considered uncertain. Therefore, the names Megapnosaurus rhodesiensis and Coelophysis rhodesiensis are both considered possibly correct names for the type species of Syntarsus Raath 1969, though here the name Megapnosaurus rhodesiensis is preferred.

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The Mosasaur
Volume 12, July 2022
The Journal of the Delaware Valley Paleontological Society
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TAXONOMIC NOTES ON MEGAPNOSAURUS AND
‘SYNTARSUS’ (THEROPODA: COELOPHYSIDAE)
SKYE N. MCDAVID1 and JEB E. BUGOS2
1 Independent, 33 Norman Drive, Rye, NY, 10580, United States (corresponding author)
mail@skyemcdavid.com https://orcid.org/0000-0003-2529-1812
2 Elevation Science Institute, 1900 Benjamin Franklin Parkway, Philadelphia, PA, 19103, United
States jbugos@elevationscience.org https://orcid.org/0000-0003-2336-1442
ABSTRACT - The genus name Syntarsus Raath 1969 is preoccupied by the genus Syntarsus
Fairmaire 1869. The replacement name Megapnosaurus Ivie et al. 2001 was proposed but its usage
is inconsistent due to both controversy on the validity of the nomenclatural act proposing
Megapnosaurus and possible synonymy between it and Coelophysis Cope 1889. The nomenclatural
act proposing Megapnosaurus is found to be valid, while synonymy between the genera
Megapnosaurus and Coelophysis is considered uncertain. Therefore, the names Megapnosaurus
rhodesiensis and Coelophysis rhodesiensis are both considered possibly correct names for the type
species of Syntarsus Raath 1969, though here the name Megapnosaurus rhodesiensis is preferred.
Keywords: Megapnosaurus, Coelophysis, Theropoda, Taxonomy
INTRODUCTION
The theropod dinosaur genus Syntarsus Raath 1969,
with type species Syntarsus rhodesiensis Raath
1969, was named based on fossils from
Nyamandhlovu, Zimbabwe (then Rhodesia). (Raath,
1969) Its generic name is preoccupied by the genus
Syntarsus Fairmaire 1869, a modern beetle from
Madagascar. (Ivie et al., 2001) In accordance with
the International Code of Zoological Nomenclature,
Ivie et al. (2001) proposed the replacement name
Megapnosaurus. Most recent authors (e.g., Griffin
and Nesbitt, 2016; Barta et al., 2018; Griffin, 2018;
Ezcurra et al., 2021; Brody, 2021, Spiekman et al.,
2021) have followed this and used the name
Megapnosaurus rhodesiensis to refer to the species
originally described as Syntarsus rhodesiensis.
However, this has not been followed universally.
The genus Syntarsus Raath 1969 has been
considered by some authors to be synonymous with
the genus Coelophysis Cope 1889. (Paul, 1993;
Bristowe and Raath, 2004; Yates, 2005; Paul, 2016).
Some authors have continued to refer to the
dinosaur genus as Syntarsus despite a replacement
name being proposed. (Bristowe and Raath, 2004;
Tyloski and Rowe, 2004.) Additionally, Ezcurra
(2007) considers rhodesiensis a species of
Coelophysis but treats Syntarsus as a valid genus
containing the species Syntarsus kayentakatae
Rowe 1989, which was originally described as a
second species of Syntarsus Raath. (Rowe, 1989)
Ezcurra and Brusatte (2011) follow Ezcurra (2007) in
their usage of Coelophysis rhodesiensis, though they
refer to the species originally described as Syntarsus
kayentakatae as ‘Syntarsus’ kayentakatae, with
quotation marks in recognition of the preoccupied
status of Syntarsus, despite the replacement name
Megapnosaurus having been proposed.
INSTITUTIONAL ABBREVIATIONS
AMNH - American Museum of Natural History, New
York, United States

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BP - Bernard Price Institute for Palaeontological
Research (University of the Witwatersrand),
Johannesburg, South Africa
CMNH - Cleveland Museum of Natural History,
Cleveland, United States
NHMUK - Natural History Museum, London, United
Kingdom
QG - Zimbabwe Natural History Museum, Bulawayo,
Zimbabwe
TAXONOMIC VALIDITY OF Syntarsus Fairmare
1869
The genus Syntarsus Fairmaire 1869 is a modern
beetle (Insecta: Coleoptera) from Madagascar.
(Marie and Lesne, 1940) According to Ivie and
Ślipiński (1990), the genus is a junior synonym of
Cerchanotus Erichson 1845. The publication
proposing the name is found to fulfill the
requirements of the International Code of
Zoological Nomenclature. Furthermore, multiple
later sources refer to it (e.g., Marie and Lesne,
1940; Ślipiński, 1985, Ivie and Ślipiński 1990; Ivie
et al., 2001) and none question the validity of the
nomenclatural act. Therefore, it is here
considered to have been validly named. Even
though it is a junior synonym of Cerchanotus, the
name Syntarsus remains unavailable for a new
genus per the Code. (Ivie et al., 2001; ICZN 1999)
TAXONOMIC VALIDITY OF Megapnosaurus Ivie et
al., 2001
Megapnosaurus was proposed as a replacement for
the preoccupied Syntarsus Raath 1969 by Ivie et al.,
(2001). The publication proposing this name fulfills
all requirements of the International Code of
Zoological Nomenclature for a replacement name.
It is therefore considered to have been validly
named, despite a possible synonymy with
Coelophysis discussed later.
ETHICS OF THE NAMING OF Megapnosaurus
If a taxonomic name is invalid (preoccupied or
incorrectly formulated), then it is considered ethical
to contact its original describer or describers to
inform them of the problem so that they can correct
their own error. If the original describer or
describers are unreachable (for example if they are
deceased or do not respond to correspondence)
then the person who learns of the error will typically
publish a correction. Ivie attempted to contact
Raath but never received a reply. He and coauthors
proceeded with publication of the replacement
name after two years, and after being (incorrectly)
told by dinosaur paleontologist John “Jack” Horner
that Raath was deceased. (Michael Ivie, pers.
comm.)
The naming of Megapnosaurus was described as
“facetious” by Bristowe and Raath (2004), likely due
to it having a humorous etymology.
Megapnosaurus is derived from Ancient Greek and
translated by Ivie et al. (2001) as “big dead lizard,”
though perhaps a more accurate translation would
be “big lizard without breath.” They say they chose
this name because “to the scale of an entomologist,
[Megapnosaurus] looks like a big dead lizard.”
Although humorous etymologies are uncommon in
vertebrate paleontology, they are common in
entomology. The entomologists who named
Megapnosaurus were acting in a manner that is
standard in their field, and compliant with the Code
of Ethics of Zoological Nomenclature, which
requires waiting one year before considering the
original describer unreachable. (Appendix A of ICZN,
1999)
Regardless of the ethics surrounding the naming of
Megapnosaurus, the publication naming it is
taxonomically valid, and it remains the correct
name for the dinosaur originally described as
Syntarsus Raath 1969 if it is not considered a
member of the genus Coelophysis.

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SYNONYMY OF Megapnosaurus AND Coelophysis
The genus Megapnosaurus was validly named as a
replacement for the preoccupied name Syntarsus,
and therefore is the correct name for the dinosaur
genus if there is no older synonym. (ICZN, 1999)
There are no older names that are definitively
synonymous with Megapnosaurus, though there is
one possible senior synonym: Coelophysis. In fact,
Paul (1993) suggested that Coelophysis bauri was a
possible nomen dubium and suggested the use of
Syntarsus colberti for the Ghost Ranch theropods. A
diagnostic neotype (AMNH 7224) was later selected
from among the Ghost Ranch specimens to replace
the possibly non-diagnostic lectotype of
Coelophysis bauri, making Coelophysis bauri the
correct name for the Ghost Ranch theropods. (ICZN,
1996)
Bristowe and Raath (2004) argued that Coelophysis
and Megapnosaurus were synonymous and treated
the name Megapnosaurus as invalid, instead using
the name ‘Syntarsus’ rhodesiensis with the genus in
quotation marks to indicate that the species
rhodesiensis could not be assigned to the
preoccupied genus Syntarsus. In this same paper,
they described a juvenile skull (QG165) which they
referred to Coelophysis rhodesiensis. This skull is
similar to CMNH 50957, a juvenile Coelophysis bauri
skull from Ghost Ranch, which will be described by
us in detail in a later publication.
On the other hand, phylogenetic analysis by Ezcurra
et al. (2021) found that the genus Coelophysis
would be polyphyletic if it included both bauri and
rhodesiensis, supporting the separation of the
genera Megapnosaurus and Coelophysis. Another
analysis by Martínez and Apaldetti (2017) found
that Coelophysis bauri was the sister taxon to the
clade containing Coelophysis rhodesiensis,
Camposaurus Hunt et al. 1998, and Lucianovenator
Martínez and Apaldetti 2017, with the relationships
between the latter three being uncertain, making
the genus Coelophysis either paraphyletic or
polyphyletic if rhodesiensis is included. Barta et al.
(2018) also noted anatomical differences between
the two species. They treated Megapnosaurus as a
separate genus from Coelophysis, but the
differences they described could be argued to
represent differences between congeneric species.
The genus Megapnosaurus is here considered to be
likely distinct from Coelophysis, but in need of
further research.
OTHER SPECIES AND SPECIMENS OF ‘Syntarsus’
Raath 1969
Rauhut and Hungerbühler (1998) referred a
theropod specimen from Wales, UK to Syntarsus sp.
This specimen (NHMUK PV R 37591) was later
determined by Spiekman et al. (2021) to be a non-
Coelophysid Coelophysoid and placed in the new
genus and species Pendraig milnerae Spiekman et
al. 2021. This interpretation is followed here, and
Pendraig is considered valid and distinct from
Coelophysis and Megapnosaurus.
Munyikwa and Raath (1999) described a snout tip
(BP/1/5278) which they referred to Syntarsus
rhodesiensis from the Early Jurassic Elliot Formation
of South Africa. This specimen was reassessed by
Yates (2005) who tentatively referred it to
Dracovenator regenti Yates 2005. Here we follow
Yates’ (2005) tentative referral but want to
emphasize that this referral is tentative.
Syntarsus kayentakatae was named as a second
species of the genus Syntarsus Raath 1969, not as a
species of the genus Syntarsus Fairmaire 1869.
(Rowe, 1989) Syntarsus Raath 1969, if not
synonymous with Coelophysis, is properly called
Megapnosaurus, so the species Syntarsus
kayentakatae would normally be transferred to the
genus Megapnosaurus as Megapnosaurus
kayentakatae. Indeed, this combination is proposed
by Ivie et al., (2001) and used by some subsequent
authors (e.g., Senter and Robins, 2015). However,
multiple phylogenetic analyses found that the
placement of kayentakatae in either
Megapnosaurus or its possible synonym

4 THE MOSASAUR
Coelophysis would render its genus polyphyletic.
(Martínez and Apaldetti, 2017; Ezcurra et al, 2021)
It therefore cannot be considered part of the genera
Megapnosaurus or Coelophysis, most likely
representing its own genus. It is thus recommended
that this species provisionally be referred to as
‘Megapnosaurus’ kayentakatae, with quotation
marks indicating a problematic genus assignment,
until a new genus is formally described for this
species.
CONCLUSION
The species originally described as Syntarsus
rhodesiensis cannot correctly be called Syntarsus
rhodesiensis. The proper replacement name is
Megapnosaurus rhodesiensis. Megapnosaurus is
possibly a junior synonym of Coelophysis, but until
this is firmly proven or disproven, the placement of
the species in either the genus Megapnosaurus or
Coelophysis is considered acceptable. Usage of the
name Megapnosaurus rhodesiensis is
recommended. Usage of the name Coelophysis
rhodesiensis is neither recommended nor
discouraged. Usage of the name Syntarsus
rhodesiensis is discouraged. The species originally
described as Syntarsus kayentakate most likely
represents a different genus from Megapnosaurus
rhodesiensis, but until this genus is formally named,
the provisional name ‘Megapnosaurus’
kayentakatae is recommended.
ACKNOWLEDGEMENTS
The authors wish to thank Tyler Greenfield for
help finding nineteenth-century literature.
REFERENCES
Barta, D., Nesbitt, S.J., Norell, M.A. (2018) The
evolution of the manus of early theropod
dinosaurs is characterized by high inter- and
intraspecific variation. Journal of Anatomy 232(1):
80-104
Bristowe, A. and Raath, M. (2004) A juvenile
coelophysoid skull from the Early Jurassic of
Zimbabwe, and the synonymy of Coelophysis and
Syntarsus. Palaeontologia africana, 40(40), 31-41.
Brody, E. M (2021) Darting towards Storm Shelter:
A minute dinosaur trackway from southern Africa.
South African Journal of Science 117(5-6), 1-11
Cope, E.D. (1889). On a new genus of Triassic
Dinosauria. The American Naturalist. 23(271):
626.
Ezcurra, M. D. (2007). The cranial anatomy of the
coelophysoid theropod Zupaysaurus rougieri
from the Upper Triassic of Argentina. Historical
Biology, 19(2), 185–202.
Ezcurra, M.D. and Brusatte, S.L. (2011) Taxonomic
and phylogenetic reassessment of the early
neotheropod dinosaur Camposaurus arizonensis
from the Late Triassic of North America.
Palaeontology. 54:4, 763-772
Ezcurra, M. D., Butler, R.J., Maidment, S.C.R,
Sansom, I.J., Meade, L.E., Radley, J.D. (2021) A
revision of the early neotheropod genus
Sarcosaurus from the Early Jurassic (Hettangian-
Sinemurian) of Central England. Zoological
Journal of the Linnaean Society 191:1, 113-149
Fairmaire, L. (1869) Notes sur les Coléptères
recueillis par Charles Coquerel à Madagascar et
sur les côtes d’Afrique, 2e Partie. Annales de la
Société Entomologique de France 4:9, 179-260 [in
French]
Griffin, C.T. and Nesbitt, S.J. (2016) Anomalously
high variation in postnatal development is
ancestral for dinosaurs but lost in birds.
Proceedings of the National Academy of Sciences
of the United States of America, 113(51) 14757-
14762
Griffin, C.T. (2018), Developmental patterns and
variation among early theropods. Journal of
Anatomy, 232: 604-640.

THE MOSASAUR 5
ICZN - International Commission on Zoological
Nomenclature (1996). Opinion 1842: Coelurus
bauri Cope, 1887 (currently Coelophysis bauri;
Reptilia, Saurischia): lectotype replaced by a
neotype. Bulletin of Zoological Nomenclature.
53(2): 142–144.
ICZN - International Commission on Zoological
Nomenclature (1999). International Code of
Zoological Nomenclature. Fourth Edition. The
International Trust for Zoological Nomenclature,
London.
Ivie, M. A. and Ślipiński, S. A. (1990). Catalog of the
genera of world Colydiidae (Coleoptera) Annales
Zoologici 43(supp1)
Ivie, M. A., Ślipiński, S. A., and Wegrzynowicz, P.
(2001). Generic homonyms in the Colydiinae
(Coleoptera: Zopheridae). Insecta Mundi 15(1)
63-64
Marie, R. and Lesne, P (1940) Supplément au
catalogue des Coléoptères de la région malgache
décrits ou mentionnés par L. Fairmaire (1849-
1906) Bulletin du Muséum national d'histoire
naturelle 2(4) 170-171 [in French]
Martínez, R. N. and Apaldetti, C. (2017) A Late
Norian—Rhaetian Coelophysid Neotheropod
(Dinosauria, Saurischia) from the Quebrada Del
Barro Formation, Northwestern Argentina.
Ameghiniana 54(5):488-505
Munyikwa, D. and Raath, M.A. (1999) Further
material of the Ceratosaurian Dinosaur Syntarsus
from the Elliot Formation (Early Jurassic) of South
Africa. Paleontologia africana 35 55-59
Paul, G. S. (1993). Are Syntarsus and the Whitaker
quarry theropod the same genus? in Lucas, S. G.,
and Morales, M. The Nonmarine Triassic: Bulletin
of the New Mexico Museum of Natural History
and Science No. 3
Paul, G.S. (2016) The Princeton Field Guide to
Dinosaurs, 2nd edition. Princeton University
Press.
Raath, M. A. (1969). A new Coelurosaurian dinosaur
from the Forest Sandstone of Rhodesia. Arnoldia
4(28) 1-25
Rauhut, O.W.M. and Hungerbühler A. (1998) A
review of European Triassic Theropods. GAIA 15:
75-88
Rowe, T. (1989) A new species of the theropod
dinosaur Syntarsus from the Early Jurassic
Kayenta Formation of Arizona. Journal of
Vertebrate Paleontology 9(2): 125-136
Senter, P., Robins, J.H. (2015) Resting Orientations
of Dinosaur Scapulae and Forelimbs: A Numerical
Analysis, with Implications for Reconstructions
and Museum Mounts. PLoS ONE 10(12):
e0144036.
Ślipiński, S. (1985). Notes rectificatives concernant
les publications de Roger Dajoz relatives aux
Colydiidae et Cerylonidae (Coleoptera) Revue
suisse de zoologie 92:613-619 [in French]
Spiekman, S.N.F., Ezcurra, M.D., Butler, R.J., Fraser,
N.C., and Maidment, S.C.R. (2021) Pendraig
milnerae, a new small-sized coelophysoid
theropod from the Late Triassic of Wales. Royal
Society Open Science 8:210915
Tyloski, R. S., and Rowe, T. (2004) Ceratosauria in
Weishampel, D.B., Dodson, P., Osmólska, H. The
Dinosauria, 2nd edition. University of California
Press
Yates, A. M. (2005) A new theropod dinosaur from
the Early Jurassic of South Africa and its
implications for the early evolution of theropods.
Paleontologia africana 41: 105-122
.

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