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New eugeneodontid sharks from the Lower Triassic Sulphur Mountain Formation of Western Canada

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Egeneodontid sharks, previously believed to have become virtually extinct during the great end-Permian extinction event, are here shown to be diverse in the Early Triassic of western Canada. Although the specimens are probably predominantly Olenekian in age, they show an abundance similar to that of the Late Permian of East Greenland. Similar in size and morphology to their Palaeozoic predecessors, this diverse assemblage is seen to have a short duration within the Early Triassic. A number of identifiable dentitions and postcranial skeletal remains suggest the presence of at least two caseodontid species (Caseodus varidentis sp. nov. and Fadenia uroclasmato sp. nov.) and an edestoid (Paredestus bricircum gen. et sp. nov.) Many other specimens recovered from the Lower Triassic Vega-Phroso Siltstone Member (Sulphur Mountain Formation) at Wapiti Lake are too poorly preserved for identification but help demonstrate the major taxonomic problems in eugeneodontid systematics. We discuss the survival of this highly specialized group of 'sharks' and comment on their biogeographical distribution across the Permo-Triassic boundary.
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doi:10.1144/SP295.3 2008; v. 295; p. 9-41 Geological Society, London, Special Publications
Raoul J. Mutter and Andrew G. Neuman
Mountain Formation of Western Canada
New eugeneodontid sharks from the Lower Triassic Sulphur
Geological Society, London, Special Publications
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© 2008 Geological Society of
New eugeneodontid sharks from the Lower Triassic Sulphur
Mountain Formation of Western Canada
RAOUL J. MUTTER1& ANDREW G. NEUMAN2
1
Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7
5BD, UK (e-mail: R.Mutter@nhm.ac.uk)
2
Royal Tyrrell Museum of Palaeontology, P.O. Box, Drumheller, Alberta, T0J 0Y0, Canada
(e-mail: Andrew.Neuman@gov.ab.ca)
Abstract: Eugeneodontid sharks, previously believed to have become virtually extinct during the
great end-Permian extinction event, are here shown to be diverse in the Early Triassic of western
Canada. Although the specimens are probably predominantly Olenekian in age, they show an
abundance similar to that of the Late Permian of East Greenland. Similar in size and morphology
to their Palaeozoic predecessors, this diverse assemblage is seen to have a short duration within the
Early Triassic. A number of identifiable dentitions and postcranial skeletal remains suggest the
presence of at least two caseodontid species (Caseodus varidentis sp. nov. and Fadenia uroclas-
mato sp. nov.) and an edestoid (Paredestus bricircum gen. et sp. nov.) Many other specimens
recovered from the Lower Triassic Vega-Phroso Siltstone Member (Sulphur Mountain Formation)
at Wapiti Lake are too poorly preserved for identification but help demonstrate the major taxo-
nomic problems in eugeneodontid systematics. We discuss the survival of this highly specialized
group of ‘sharks’ and comment on their biogeographical distribution across the Permo-
Triassic boundary.
The order Eugeneodontida sensu Zangerl, 1981
comprises ‘Edestida’ and ‘Helicoprionida’ sensu
Moy-Thomas & Miles (1971). Well-preserved
cranial material of eugeneodontid sharks was
described by Zangerl in 1966. Descriptions of frag-
mentary dentitions have also been published over
the past half century by Nielsen (1932, 1952),
Bendix-Almgreen (1966, 1975a, 1975b, 1976) and
Zangerl (1979, 1981). The highly specialized euge-
neodontid sharks bear tooth whorls and are predomi-
nantly known from the Carboniferous and Permian.
They are practically unknown from the Triassic.
Zhang (1976) reported a partial tooth-whorl from
the Lower Triassic of western China and one denti-
tion fragment has been described from the (?earliest)
Triassic of Greenland (Nielsen 1952).
The skeletons of all edestoids are believed to
have been very poorly calcified, even at their
latest stages in life, and the anatomy of crania, post-
crania and dentitions can only be partly recon-
structed by careful comparison of numerous
fragmentary specimens. It is also assumed that the
geologically younger (more advanced) members
were less extensively calcified than the geologically
older (more primitive) members (Zangerl 1981).
The taxonomic framework followed here was
established by Zangerl (1981) who subdivided the
order Eugeneodontida into two superfamilies each
with two families (Superfamily Caseodontoidea
Zangerl, 1981: Caseodontidae Zangerl, 1981 and
Eugeneodontidae Zangerl, 1981; and Superfamily
Edestoidea Hay, 1930: Agassizodontidae Zangerl,
1981 and Edestidae Jaekel, 1899). The superfamily
Caseodontoidea comprises at least 10 genera,
including the relatively well-known genera Caseo-
dus and Fadenia (both Caseodontidae), and the
superfamily Edestoidea comprises at least 12
genera including the relatively well-known agassi-
zodontid Sarcoprion. The fossil record of the best-
known members supports the currently proposed
sister-group relationship between Caseodontoidea
and Edestoidea (Zangerl 1981, p. 91), although
the taxonomic framework and intrarelationships
must be considered a working hypothesis.
The significance of Early Triassic
eugeneodontid sharks
Here we describe the first articulated remains,
partial dentitions and postcranial material of euge-
neodontids definitely of Early Triassic age. Pre-
vious reports of eugeneodontids from the Triassic
include only two poorly known species. Paraheli-
campodus spaercki Nielsen, 1952 from the Wordy
Creek Formation of East Greenland is known
from a single dentition fragment, and is the only
species described as coming from the Lower Trias-
sic of this area. The rock on which the specimen is
located has been abraded, so we believe the
From:CAVIN, L., LONGBOTTOM,A.&RICHTER, M. (eds) Fishes and the Break-up of Pangaea.
Geological Society, London, Special Publications, 295, 9– 41.
DOI: 10.1144/SP295.3 0305-8719/08/$15.00 #The Geological Society of London 2008.
specimen could also be reworked from Permian
rocks. All other eugeneodontid shark remains
from East Greenland, including remains from the
same locality as P. spaercki, are Late Palaeozoic
in age. Additionally, recent re-investigation of the
Wordy Creek Fm suggests that the most prolific
fish assemblage (fish zone II and possibly other
zones) described as Early Triassic in age, may in
fact be Late Permian (Stemmerik et al. 2003).
Zhang (1976) described two Helicampodus-like
dentition fragments from near Qubu in Dingri (Xian
County) as Sinohelicoprion quomolangma. These
finds may be Early Triassic in age but the speci-
mens’ taxonomic position is equivocal and in
need of re-description (Chang & Jin 1996; Chang
& Miao 2004).
Geological setting
The Wapiti Lake fossil site in Wapiti Lake Provin-
cial Park (British Columbia) yields a remarkable
‘Fossillagersta
¨tte’. The site, normally referred to
as ‘Ganoid Ridge’ or ‘Ganoid Range’, contains
various localities where numerous fish fossils have
been collected from outcrops of the Vega-Phroso
Siltstone Member. Wapiti Lake and coeval
localities contain the first Mesozoic strata yielding
articulated eugeneodontids. The approximate
Early Triassic age can be given with confidence,
although a more precise dating is currently not poss-
ible for the various reasons outlined below. For a
more detailed account of the geological setting
and collecting sites in the Wapiti Lake locality,
see Neuman & Mutter (2005). Over the past 20
years of extensive field work in this area, a great
number of well-preserved fish specimens, collected
from the slopes of the cirques on ‘Ganoid Range’,
have been curated in Canadian museums and col-
lections, and at AMNH (New York). Schaeffer &
Mangus (1976) provided the first detailed account
of the fish fauna from the Vega-Phroso Member
of the Sulphur Mountain Fm. They concentrated
on specimens mainly collected from the Ganoid
Ridge by far the most prolific of all fossil sites
in British Columbia and Alberta. Neuman (1992)
later outlined the fossil content of the two distinc-
tive vertebrate faunas – Early Triassic and Middle
Triassic in age respectively. The Laboratory for
Vertebrate Paleontology of the University of
Alberta (UALVP) in collaboration with the Royal
Tyrrell Museum (TMP) recently undertook
additional field work to expand their collection
and undertake more detailed and systematic investi-
gations of a suitable outcrop section (see Mutter &
Neuman 2006).
Eugeneodontid remains from contemporaneous
Alberta sites and horizons within the Sulphur
Mountain Fm were first noted by Lambe (1916) as
?Edestus from the Permian of Alberta’. Neuman
(1992) listed ‘?Edestodus Obruchev, 1953’ as
occurring in the Lower Triassic of the Sulphur
Mountain Fm.
We now understand there are probably several
different fish assemblages within the Lower Triassic
of the Ganoid Range at Wapiti Lake, ranging from
Induan to Ladinian in age (Neuman 1992; Neuman
& Mutter 2005; Mutter & Neuman 2006). A single
articulated hybodontoid specimen can be shown to
be Olenekian in age (see below and Mutter et al.
2006). According to our present understanding, the
eugeneodontid remains described here are most
likely of early Olenekian (early Smithian) or slightly
younger age. On the same block as the holotype
specimen TMP 86.42.4 (Fadenia uroclasmato sp.
nov.) is a specimen of Helmolepis cyphognathus
Neuman & Mutter, 2005, corroborating the mid-
Early Triassic age.
But no complete species lists have been compiled
of in situ fossils in any measured section. It seems
evident, however, that at least three major fish
faunas (yielding articulated fish skeletons),
currently termed ‘fish assemblages’, are stratigraphi-
cally distinct. Fragmentary fish fossils, brachiopods,
bivalves, ammonoids and phyllocarids are preserved
within and between the fish beds. Ammonoids and
conodonts from the fish beds indicate an Induan
to Olenekian age (Mutter & Neuman 2006). An
ammonoid species, presumably coming from
eugeneodontid-bearing concretions, is dated as Late
Olenekian (Spathian; cf. Xenoceltites subevolutus,
identification pers. comm., Hugo Bucher 2004).
Only a few fish remains are preserved in concre-
tions, and the exact stratigraphic provenience of the
majority of eugeneodontids from Wapiti Lake is
unknown except for a single specimen, which has
been recovered in situ. This single specimen recov-
ered from systematic collecting activities in a
section on top of the NW ridge of C-cirque (see
Neuman 1992 or Mutter 2004 for specific sites) is
an anterior body portion including the tail (speci-
men TMP 86.42.4) of Fadenia uroclasmato sp.
nov., This specimen indicates an approximately
Early Olenekian (Scythian) age.
Although the precise age of the majority of
specimens is not yet determined, all specimens are
Early Triassic in age. A single hybodontoid speci-
men (UALVP 19191) from Wapiti Lake, however,
is Late Olenekian (Spathian) in age, as suggested
by the conodont Neospathodus homeri (identifi-
cation pers. comm., Mike Orchard 2004). Specimen
TMP 86.42.4 (mentioned above) is the only in-situ
specimen whose stratigraphic origin is reportedly
Lower Olenekian (Upper Scythian). The calcareous
concretions with fish remains, including the holo-
type of Caseodus varidentis sp. nov., are occasion-
ally found in talus and are of uncertain stratigraphic
R. J. MUTTER & A. G. NEUMAN10
origin. OthocerasOphiceras-like ammonite
impressions are sometimes associated with flattened
eugeneodontids preserved in darkish, slightly bitu-
minous shales but no more precise age than Early
Triassic can at present be attributed to the speci-
mens found in scree.
The small actinopterygian Helmolepis cyphog-
nathus Neuman & Mutter, 2005 is preserved in an
immediately-underlying layer of specimen TMP
86.42.4 (Fadenia uroclasmato sp. nov.) and suggests
an Early Triassic age (early Olenekian) of that par-
ticular specimen (Neuman & Mutter 2005). Speci-
men TMP 89.127.43 (Eugeneodontida gen. et sp.
indet.) was collected high in the talus of D-cirque,
either immediately below or above the ‘marker
bed’ (see Mutter & Neuman 2006) and is hence
also most probably mid-Early Triassic (early Olene-
kian; Smithian) in age. Specimen TMP 2001.15.03
(Eugeneodontida gen. et sp. indet.) is particularly
interesting with regard to the stratigraphic prove-
nance; it comes from the southernmost part of the
Ganoid Ridge in ‘Mount Becker’. Systematic rock
samples in the same year and area yielded various
Induan and Olenekian conodont samples (‘Diener-
ian’, ‘Smithian’, ‘upper Smithian’, ‘c. Smithian–
Spathian Boundary’ and ‘Spathian’ samples [pers.
comm. Mike Orchard, Vancouver]). Specimen
UALVP 46539 (described in open nomenclature)
comes from high up in the talus of C-cirque just
underneath the overturned section, which is the
lowest part of the V– P Siltstone Member.
Neuman (1992) listed ?Edestodus in his first
comprehensive faunal list of the Wapiti Lake fish
material, but no detailed taxonomic study was poss-
ible at the time. Four of the eugeneodontid speci-
mens now identifiable at the species level were
recovered in recent field trips, and detailed investi-
gation revealed that complementing parts and
counterparts recovered on earlier field trips had
been stored under different collection numbers.
Some of these had been collected separately over
the course of several years or stored in different col-
lections. Here an attempt is made to include skeletal
information of poorly preserved specimens and in
particular, their cartilaginous elements. Very little
is yet known about the eugeneodontid skeleton in
general as it appeared to be often poorly calcified.
Among the remains from the Canadian Rockies,
however, we find almost every part of the eugeneo-
dontid shark body reasonably well-calcified, even if
poorly-preserved.
Material, methods and background
of investigations
Most vertebrate fossils from Wapiti Lake are pre-
served in exceedingly hard siltstone, predominantly
with low carbonate content, or in dark (slightly
bituminous) and silty shales. All specimens investi-
gated in this study come from Wapiti Lake Provin-
cial Park, the ‘Ganoid Ridge’, where much of the
lower part of the Sulphur Mountain Formation, the
Vega-Phroso Siltstone Member, is exposed. Exact
horizons, however, are not known for the majority
of specimens and specific sites in the ‘Ganoid
Ridge’ are referred to below as respective cirques
(see sections below; Neuman 1992; Mutter 2004).
All specimens are most probably Early Triassic in
age, presumably early Olenekian (‘Smithian’).
Most specimens are dorso-ventrally flattened and
preserved in parts and counterparts. Only minor prep-
aration can be successfully carried out. Rubber peels
were taken from specimens consisting of imprints
alone. Some specimens, however, are preserved
in 3D and are currently undergoing CT scanning.
Specimens used for thin sectioning were embedded
in resin and were ground using corundum powder.
Eugeneodontid sharks are predominantly known
from isolated teeth and partial tooth-whorls. Numer-
ous mesial and distal teeth have been reported but
their taxonomic value is questionable, unknown or
reportedly equivocal (e.g. Zangerl 1981). More
complete skeletal remains and partially associated
sharks are rare but known from a variety of Palaeo-
zoic sites. The dental remains described from the
Upper Permian of East Greenland (Nielsen 1952;
Bendix-Almgreen 1976) come closest in stratigra-
phy and morphology to the material described
here. The eugeneodontid material in the Geological
Museum in Copenhagen, however, could not be
located and investigated. Because of this, most
cranial and postcranial remains are compared to iso-
lated material held at the American Museum of
Natural History (AMNH, New York) and the
Natural History Museum (NHM, London). A list
of comparative material used for this study is
given in Appendix 1.
Comparison with skeletal material from the
Carboniferous of East Greenland and from the Penn-
sylvanian Mazon Creek fauna and Logan quarry
shales of Illinois and Indiana (Zangerl 1966, 1979)
or from the Upper Devonian Cleveland Shale
(Bendix-Almgreen 1976) is largely restricted to pub-
lished accounts. However, the sample from Wapiti
Lake shows a similar range of diversity as previously
recorded from the Upper Permian of the Wordy
Creek Fm of East Greenland with symphysial teeth
assigned to three different genera. The little known
Latin ending ‘-ad’ is used in anatomical descriptions
(e.g. laterad) to indicate the direction.
Institutional abbreviations
AMNH, American Museum of Natural History
(New York, USA); BMNH, Natural History
TRIASSIC EUGENEODONTID SHARKS 11
Museum (London, UK); EOSUV, School of Earth
and Ocean Sciences, University of Victoria
(British Columbia, Canada); TMP, Royal Tyrrell
Museum of Palaeontology (Drumheller AB,
Canada); UAEAS, University of Alberta Earth and
Atmospheric Sciences (Edmonton AB, Canada);
UALVP, University of Alberta Laboratory for
Vertebrate Paleontology (Edmonton AB, Canada).
Systematic palaeontology
Class Chondrichthyes Huxley, 1880
Subclass Elasmobranchii Bonaparte, 1838
Order Eugeneodontida Zangerl, 1981
Superfamily Caseodontoidea Zangerl, 1981
Family Caseodontidae Zangerl, 1981
Note: Zangerl (1981, p. 79) provides a comprehen-
sive account of the family but refrains from provid-
ing observable caseodontid features in actual
species. Apparently, the caseodontids (Caseodus
Zangerl, 1981; Romerodus Zangerl, 1981; Ornitho-
prion Zangerl, 1966; Fadenia Nielsen, 1952 and
Erikodus Nielsen, 1952) can only be characterized
by tendencies resulting in fusion of haemal arch
elements in the tail and ‘more tumid or bulbous’
teeth: these features are in contrast to other
eugeneodontids who show acuminate teeth and
symphyseal teeth with cutting blades (tips of tooth
crowns) but the structure of the caudal fins in
these sharks is currently unknown. Abbreviations
used in text and text-figures are given before
the acknowledgements.
Genus Caseodus Zangerl, 1981
Type species. Caseodus basalis (Cope, 1894)
Diagnosis (emended from Zangerl [1981]). Teeth
lacking strong crenulations in lingual wall of
upper jaw teeth; notable variation; symphysial
teeth not particularly enhanced; crown angle
varying from 65 degrees in symphysial and up to
120 degrees in mesial teeth; structure of tooth
whorl unknown.
Caseodus varidentis. sp. nov. Figures 1–8
Holotype. TMP 86.42.3 (from C-cirque).
Etymology. Vari- (from Latin, meaning ‘different’)
and -dentis (from Latin, meaning ‘tooth’), referring
to the variable dentition.
Diagnosis. Small sharks, estimated body length 1 m
to 1.5 m and fairly broad skull in dorsal view; orna-
mentation on dentition highly variable, consisting
predominantly of blunt or pavement teeth; lower
jaws fused at symphysis where crown shoulders in
symphysial teeth meet at about 658(acuminate, roof-
shaped); mesial teeth with variably well developed
central cusp (linguo-labially expanded, crowns
enclose an angle of 100– 1208); extensive crenulation
at least in lateral teeth of lower jaw; mesial teeth in
upper jaw probably lack ornament on labial wall (or
ornament is poorly developed) but buttresses in
almost all teeth conspicuously developed.
Description. Specimen TMP 86.42.3 is an almost
complete, 3-D preserved neurocranium (Figs 1 2)
in a concretion with the lower jaws and many
teeth preserved in situ (Figs 1 6). The neurocra-
nium slants from the occipital region toward the
anterior region and possesses a very short postorbi-
tal portion. The tip of the rostrum and the extension
of the lower jaws are missing, and only part of the
ventral side of the neurocranium is exposed.
Additional preparation could expose more of the
ventral side of the skull if the exposed ventral and
lateral sides are stabilized (Figs 1 6).
The preserved parts of the neurocranium
measure 225 mm in length (from the posterior rim
of the neurocranium to the anterior tip of the
rostrum) and 200 mm in width. The skull is rela-
tively broad. The entire dorsal surface of the neuro-
cranium, including the rostrum, is covered by a
shagreen of single or multiple lepidomoria. The
supraorbital and central area of the skull are
covered by single lepidomoria whereas the entire
posterior portion of the skull is densely covered
by multiple lepidomorial denticles. Distinctive,
unique and unicuspid dermal denticles are pre-
served along the right postero-lateral rim of the
neurocranium (inset of Fig. 2). These denticles
measure at least 3 mm in length and are pointing
forward. The latter region looks as if it was more
strongly calcified and the surface, with scarce
covering of denticles, appears to have also been
underlain by uncalcified cartilage.
Fig. 1. Caseodus varidentis sp. nov., holotype specimen
TMP 86.42.3. The 3D preserved skull in dorsal view.
R. J. MUTTER & A. G. NEUMAN12
The rostral portion of the neurocranium is rela-
tively massive and broad anteriorly and tapers
slightly posteriad. The dorsal wall is slightly
curved and extends into a conspicuous sagittal
crest towards what appears to be the posterior
border of the neurocranium. Paired, small,
median circular or oblong-lateral depressions are
regularly arranged along both sides of the
dorsal crest.
The dorso-anterior portion of the neurocranium
is not as well calcified as the posterior portion.
Only the supraorbital and the postorbital processes
are thoroughly calcified. It is unclear what other
parts of the neurocranium are preserved within
the concretion.
The lower jaws (Figs 3–5) are deep anteriorly
and fused at the symphysis, containing or adjoining
a very well-calcified and massive tooth whorl (or
symphysial tooth battery) of which only a couple
of abraded tooth caps are ventrally exposed (in
the apparent cartilage [symt in Fig. 5a], see also
Fig. 6). The left lower jaw is much deeper anteriorly
than the right lower jaw; a difference that probably
resulted from dorso-ventral and slightly oblique
compression of the skull. Both halves of the lower
jaw taper posteriad and the left lower jaw shows a
double-articulation area, either with the upper jaw,
with the neurocranium or both (Fig. 3b).
There is no unequivocal evidence of upper jaws.
The right upper anterior region of the dentition,
however, is preserved partially in situ and is
visible in ventral and in dorsal view (see ‘dentition’
below). This suggests that upper jaws might have
been originally present (even if uncalcified) and
reached anterior to the level of the symphysis,
unless the upper tooth files were anchored in
the neurocranium.
Fig. 2. Caseodus varidentis sp. nov., holotype specimen TMP 86.42.3. Line drawing of dorsal view of neurocranium
and anterior portion of lower jaws. Note the inset with the unique, unicuspid denticles (spiden) covering, as preserved,
delimited parts of the posterior region of the skull.
Fig. 3. Caseodus varidentis sp. nov., holotype specimen
TMP 86.42.3. (a) neurocanium and right lower jaw in
right lateral view, showing the partly scattered, partly
in-situ dentition (close-up in Fig. 4). (b) left lower jaw
and rostral tip of neurocranium.
TRIASSIC EUGENEODONTID SHARKS 13
Dentition. The smallest preserved teeth measure
around 3 mm in width, whereas the largest ones
(although fragmentarily preserved) can be esti-
mated to have measured up to 25 mm in width.
Strong heterodonty is present. Several dozen teeth
are preserved, but only a small number of them
are preserved in articulated tooth-files (Figs 4–6).
Most teeth preserved are not found in situ, but are
partially visible; embedded in matrix or irregularly
scattered on top of each other. In general, most of
these teeth are small (several millimetres), adding
to the impression that the majority of tooth files
were made up of smallish, blunt pavement teeth
lacking a central cusp and cutting blades. Some of
the teeth in distal tooth files are quite slender in
occlusal and lateral views and have a conspicuous
longitudinal crest. Others lack this crest entirely.
There are several tooth files in mesial position.
Two different mesial tooth files are preserved with
tooth crown shoulders enclosing an angle of about
100–1208. These files show teeth oval in occlusal
view and a pronounced central cusp, which is
occasionally linguo-labially expanded or pyramidal
in occlusal outline. The symphysial tooth whorl
consists of teeth with an ornamented crown and a
pointed-acuminate apex.
Even though articulation is variable, certain
teeth can be assigned to their approximate position
in the jaws. A variety of different teeth can be ident-
ified, differing only in the presence or absence of
pronounced labial ridges and a central bulbous
cusp (see in particular Fig. 6). Upper mesial teeth
seem to have had smooth labial walls with no
ornamentation in-between the conspicuous and
well-spaced labial buttresses. Occasionally, strong
and obliquely running crests are found. Conspicu-
ous labial ridges and a vaulted central cusp are
probably present in crowns of mesial or symphysial
teeth in the upper jaw only. Some teeth, seemingly
associated with the lower jaw, show very little of
their buttresses and these may well be reduced in
the majority of these teeth. However, since these
teeth are embedded in matrix, it is possible that
these features that are otherwise quite obvious are
partly obscured. Symphysial teeth are well-
separated, seemingly erupting from cartilage, and
appear to have an acuminate cuspid tip with a
weak sagittal ridge similar to specimen UALVP
46535 (see below), but the teeth are worn and no
conspicuous blade (cutting edge of tooth crown)
can be made out. The crowns of all teeth tend to
be asymmetrical, and there is a tendency for large
teeth to develop more numerous and irregular cre-
nulations (compare Fig. 6a and b).
UALVP 46535. Specimen UALVP 46535 is a
portion of the symphysial area of a lower jaw
with 4 poorly preserved fragmentary teeth pre-
served in situ in the tooth whorl (Fig. 7). Several
other partly-preserved teeth are present and are
scattered beside the jaw elements. The majority of
tooth fragments belong to teeth that were less than
half the size of the teeth preserved in the tooth
whorl. A cluster of several fragmentary teeth
immediately to the left of the left ramus of the
lower jaw seem to have been teeth from near the
Fig. 4. Caseodus varidentis sp. nov., holotype specimen TMP 86.42.3. Lateral view of snout showing the dentition as
preserved in the right lower and upper jaw.
R. J. MUTTER & A. G. NEUMAN14
tooth whorl. The crowns of the teeth are stacked on
top of each other, are rigidly connected to the carti-
lage and may represent non-functional teeth. The
teeth of the partial tooth whorl show conspicuously
dome-shaped crowns each with a prominent sagittal
crest from which ridges descend vertically on both
shoulders. The shoulders of each symphysial tooth
crown meet at an angle of about 65708. Both
crowns of the in-situ symphysial teeth and of the
displaced stack of symphysial teeth show remnants
Fig. 5. Caseodus varidentis sp. nov., holotype specimen TMP 86.42.3. (a) sketch of the lower jaws in ventral view.
(b) enlarged details of the preserved dentition of the lower jaw.
TRIASSIC EUGENEODONTID SHARKS 15
of a very well-developed, bulbous projection on the
labial side. The blades (tips of tooth crowns) on
symphysial teeth are richly but delicately crenu-
lated, and one symphysial tooth shows a distinctive
sagittal crest. A displaced cluster of ?lateral teeth
(Fig. 7, dent) reveals that some functional teeth
had a root that was as deep as or deeper than
the crown.
Note: This specimen is associated with conodonts
that could not yet be positively identified. The
specimen may therefore provide valuable additional
Fig. 6. Caseodus varidentis sp. nov; holotype specimen TMP 86.42.3. (a) mesio-lateral teeth in occlusal view
presumably located in the lower jaw. (b) occlusal view of in-situ mesio-lateral teeth from the right upper jaw.
(c) latero-distal teeth in basal view. (d) two symphysial teeth (arrows), somewhat abraded and partly buried in cartilage.
(e) labial view of a distal tooth with slightly vaulted centre. (f) a bar-shaped distal tooth in occlusal view.
R. J. MUTTER & A. G. NEUMAN16
information in future research to determine the
relative age of this species and possibly other
eugeneodontids.
TMP 86.42.1. Specimen TMP 86.42.1 (counterpart
in the Royal British Columbia Museum, Victoria)
is similar in overall morphology to UALVP 46535
showing the two lower jaw rami in situ,an
additional cartilaginous element between the
lower jaw rami and several teeth, including the
tooth whorl. However, the lower jaw rami meet at
a less obtuse angle than in the latter specimen. In
addition, there is a long, bar-shaped cartilage
adjoining the anterior tip of the tooth whorl which
appears to be a separate, median element of the
lower jaw if compared to specimen UALVP
46535, where supposedly the same element
although more fragmentarily preserved adjoins
the anterior tip of the Meckel’s cartilages.
The teeth on the jaw cartilages are broken away
and difficult to interpret, but seem to match the
general arrangement observed in UALVP 46535.
Various tooth types are present but cannot be
easily assigned to their original position.
UALVP 47003. Specimen UALVP 47003 is a con-
cretion of a small fragment of a tooth whorl and
adjoining lateral tooth files preserved in 3D
(Fig. 8). This specimen closely matches the holo-
type specimen TMP 86.42.3 in body size. The
orientation of the tooth-bearing cartilages is diffi-
cult to assess. The largest teeth (presumably the
tooth whorl) are situated on a slightly elevated
area on the cartilage. Somewhat smaller teeth can
also be discerned immediately ?lateral to the sym-
physial tooth file. These teeth are relatively blunt
and about half as large as teeth in the tooth whorl,
diminishing gradually in size towards lateral pos-
itions. The cartilages comprising the tooth whorl
are preserved as two oblique sections (Fig. 8a
[2,3]) through the symphysial portion of the lower
jaw in UALVP 47003. Sections through the ante-
riormost portion of this specimen reveals that sym-
physial teeth and tooth files in mesial position may
look strikingly different.
All sections run obliquely through the tooth files
and expose the basal (and partly apical) osteoden-
tine and the apical orthodentine. The obliquely-cut
symphysial tooth shows an acuminate crown in
Fig. 7. Caseodus varidentis sp. nov., specimen UALVP
46535. Sketch of lower jaw symphysis with
fragmentarily preserved tooth whorl and disarticulated
mesio-lateral tooth families.
Fig. 8. Caseodus varidentis sp. nov., specimen UALVP 47003. (a) composite illustration of the obliquely cut
lower jaws and the tooth whorl with indication of presumed cutting angles (outline of block with polished surfaces at
top in [2]). (b) oblique cut through a symphysial tooth showing the extent of osteodentine (os) and orthodentine (od).
Arrows point approximately in indicated directions.
TRIASSIC EUGENEODONTID SHARKS 17
antero-posterior view and is laterally flattened
(Fig. 8b). The obliquely cut tooth clearly shows
the remainder of the ornamentation of the tooth
edge, probably consisting of cristae reaching fairly
high up the tooth crown (Fig. 8b). Apical ornamen-
tation in symphysial teeth can also be discerned in
specimen TMP 86.42.1 but the extent of wear
cannot be determined. Large vascular cavities are
located relatively far apically in these teeth. The
immediately adjoining mesial or mesio-lateral
teeth are blunt with a slightly vaulted central cusp
and show conspicuous linguo-labial projections
(cut buttresses in section Fig. 8a[1]).
The thin sections also reveal that the majority of
teeth and tooth files are covered by a quite dense
layer of lepidomoria. Lepidomorial scales are not
arranged in an obvious pattern but larger lepido-
moria always lie interior to the smaller, single lepi-
domoria, suggesting that the denticles sank into the
skin before and during decomposition of the soft
tissue. (For a description of denticles, see below.)
Comparisons. The specimens TMP 86.42.1,
UALVP 46535 and 47003 resemble the holotype
in overall morphology and state of preservation
and are thus most parsimoniously placed within
the same species.
Compared to other caseodontids, Caseodus var-
identis sp. nov. most closely resembles Caseodus
eatoni Zangerl, 1981 in overall morphology but
can readily be distinguished by tooth morphology.
Of all teeth, only the distal teeth resemble each
other in the two species, and these teeth are likely
least significant with respect to taxonomy.
Ornamented blades, as in the symphysial teeth
of Caseodus varidentis sp. nov., have not previously
been described in any other caseodontid. The mesial
teeth of the upper jaw most closely resemble the
‘symphysial teeth’ of Caseodus basalis Cope,
1894 but the mesial teeth of C. varidentis sp.
nov. have very strong crenulations. The symphysial
teeth of specimen UA 46535, although somewhat
more crenulated, resemble C. basalis (specimen
FMNH PF 2500 in Zangerl [1981; fig. 91]) closely.
Genus Fadenia Nielsen, 1932
Type species. Fadenia crenulata Nielsen, 1932
Diagnosis (emended from Zangerl [1981]).Fusiform
body shape; probably slender head (at least in some
species); articulating area of upper jaw present and
calcified; dentition consists of tumid and pavement
teeth; symphysial teeth much enlarged, bulbous and
tumid; pectoral fin with axially arranged elements
but lacking proximal series of basals; ceratotrichia
distally forked but this feature is questionably diag-
nostic (compare Bendix-Almgreen 1975b); haema-
pophysial and neurapophysial elements in caudal
fin slender-triangular and variable in number
(proximally fused to become very few elements).
Fadenia uroclasmato sp. nov. Figures 9–13.
Holotype specimen. TMP 86.42.4 (Figs 9–12). Ten-
tatively referred specimens: TMP 87.42.11,
UALVP 46526 (Fig. 13). Site: From D-ridge
[holotype], others from C-cirque (see Neuman
1992).
Etymology. Clasmato- (from Greek, meaning ‘frag-
ment’) and uro- (from Greek, meaning ‘tail’),
referring to the upper caudal fin lobe apically
supported by several short, bar-shaped
neurapophysial cartilages.
Diagnosis. The caudal fin is taken to be diagnostic of
this new species: upper lobe consisting apically of a
mosaic of small, long, asymmetrically triangular to
diamond-shaped cartilages; proximal portion of the
upper lobe supported by large triangular plates.
The morphology of the caudal fin, however, shows
strong affinities to the (yet undescribed) caudal fin
of Fadenia crenulata Nielsen, 1932 from Permian
strata of the Wordy Creek Formation in East Green-
land (figured by Zangerl 1981, fig. 89D) and is inter-
mediate in structure between Caseodus and Fadenia.
If the tentatively referred specimens (UALVP 46526
and TMP 87.42.11) are correctly placed in Fadenia
uroclasmato sp. nov., the diagnosis can be extended
as follows: slender sharks of about 1 m body size and
slender skull in dorsal view; moderate heterodonty,
consisting predominantly of smallish, blunt pave-
ment teeth; lateral teeth with extremely slender-
oblong, asymmetrical and vaulted cusp; tooth
whorl unknown.
Description. The holotype specimen TMP 86.42.4
consists of two major parts, showing the partial
anterior body (Fig. 9) and an almost completely
preserved caudal fin (Fig. 10). The remains of the
anterior body comprise the jaws and most of the
visceral skeleton elements and parts of the pectoral
girdle and fins. Two large, rectangular to oval carti-
lages and a maximum of about 15 ceratotrichia are
preserved. Two short, rod-shaped ?pectoral carti-
lages are present in front of the right pectoral fin.
The outlines of a series of at least 5 branchial
arches can be traced by the regular patches of
pharyngeal teeth/denticles (Fig. 9, bas). Both
lower jaws can be traced but the posterior end
(articulation site) is set apart and appears to have
been separately calcified. Alternatively, these
portions may represent lateral flanges of the neuro-
cranium, partly covered by the lower jaw elements.
Only imprints of very slender, slightly curved
‘?upper jaws’ are present immediately mesial to
R. J. MUTTER & A. G. NEUMAN18
the lower jaws. Along the central portion of the
lower jaws, relatively deep, slender-oblong
depressions with a broadened posterior end can be
found, which indicate the original presence of an
additional cartilage supporting the lower jaw on
each side. The mandibular rostrum is very short
and contains the entire tooth whorl, which, although
fragmentarily preserved, forms a near-complete
circle.
The pectoral fin supports include oblong, calci-
fied rods that are slightly curved distally. There
are at least 12 rays in the left pectoral fin whereas
the right pectoral contains 14 or 15 rays. Ray
number 7 is the broadest in both fins. The rays
increase in length up to ray number 9, which is
the first to fork clearly (the more anterior rays are
less clearly preserved distally in this respect).
Most of the support of the shoulder girdle is
missing but there is one short (30 mm long)
element (‘rods that are slightly curved distally’
mentioned above) on either side articulating with
the pectorals and several smaller, rod-shaped
elements that represent additional short rays of the
fins. These are lined up anterior to the fins. Two
extremely slender-oblong and curved elements
(partly covered by the right pectoral fin) are inter-
preted as scapulocoracoids (Fig. 9, ?scac), although
their shape is very unusual.
No cartilaginous elements of the branchial
arches are preserved leaving only the outline of
Fig. 9. Fadenia uroclasmato sp. nov., skull, visceral skeleton and pectoral fins as preserved in one part of specimen
TMP 86.42.4.
TRIASSIC EUGENEODONTID SHARKS 19
the basket. At least 5 branchial arches occur, which
can be traced by the shagreen of branchial teeth
lined up along the arches. There may have been a
very short or rudimentary sixth arch present at
least in the left side of the skull. Only an imprint
of part of the basibranchial is visible. Apparently,
there is a separate remnant of a cartilage abutting
the posterior end of the lower jaw on either side
and these may represent separate cartilages of the
upper jaw articulating with the neurocranium and
the lower jaws.
There are additional imprints of slightly curved
cartilages of the visceral skeleton preserved
between the lower jaws and these probably are the
remainder of the upper jaws. Both lower jaws,
including the proximal portion of the mandibular
rostrum, show well-calcified prismatic cartilage
around which numerous teeth are preserved partly
in situ and partly scattered (see below).
The caudal fin is composed of a dozen slender,
tapering and rod-shaped ceratotrichia in the lower
lobe and a complex arrangement of triangular,
diamond-shaped and rectangular haemapophysial
and, in particular, neurapophysial cartilages in the
upper lobe (Fig. 10). The rod-shaped elements in
the lower lobe may be arranged in two series but
the evidence is ambiguous. In the upper lobe, the
smallest elements enclose the distal portion of the
notochord anteriorly whereas a single, large and tri-
angular element supports the fin ventro-posteriorly.
The anterior series of cartilages in the upper lobe
decreases in size distally. In the caudal peduncle,
the preservation is less perfect and definite calci-
fications cannot be unambiguously identified.
However a short series of rod-shaped haemapo-
physes can be traced in front of the two uppermost,
horizontally oriented elements of the lower lobe.
The dentition is very incomplete but a variety of
different types of teeth are preserved. There is one
fragmentarily-preserved, but almost complete,
circle of a tooth whorl present in specimen TMP
86.42.4 (Figs 11–12). The tooth whorl is apparently
situated at the anterior tip of the lower jaw symphy-
sis and on the mandibular rostrum. The largest com-
pletely preserved tooth measures 6 mm in length
but there are several broken teeth suggesting a
maximum tooth length of 810 mm. As far as
visibly preserved, there are several tooth batteries
with enlarged teeth situated near the symphysis
(either from the upper or lower jaw).
These teeth are very poorly preserved but do not
seem to form a whorl-like series and are instead
regular tooth families, including teeth with blunt
crowns lacking the smooth and acuminate blade
of the symphysial teeth in the lower jaw. Although
the crowns in the tooth whorl are very
Fig. 10. (a) photograph and (b) sketch of the caudal fin of Fadenia uroclasmato sp. nov., as preserved in another part of
specimen TMP 86.42.4. Note the similarity with Fadenia crenulata Nielsen, 1932 in the pattern of proximal fused
neurapophysial cartilages. The relatively high counts of neurapophysial elements (ne) in the upper lobe are rather
reminiscent of the genus Caseodus.
R. J. MUTTER & A. G. NEUMAN20
fragmentarily-preserved, these teeth show evidence
that there is no significant increase in tooth size
from older to younger teeth, as in contrast in Pare-
destus gen. nov. (UALVP 46579), and the roots
form a single, solidly-fused, small and tightly
curled basis fused to the mandibular rostrum (Figs
11–12). The exact orientation of the roots is inde-
terminable as their outline cannot be followed.
Their depth measures about half the length of the
crowns. The shape of the crown is remarkably
similar to Paredestus bricircum gen. et sp. nov.
but the blade is not recurved and serration (again
poorly preserved in one tooth) may have occurred
on the lingual edge of the blade rather than on the
labial edge.
Tentatively referred specimens (UALVP 46526,
TMP 87.42.11). Specimen UALVP 46526
(Fig. 13a, b) is an anterior body section with two
pectoral fins, vague outlines and surface
depressions of the dorsoventrally flattened neuro-
cranium, the sclerotic rings, part of the branchial
skeleton with several arches and part of the tooth-
bearing jaws including a distinctive, asymmetrical
lateral tooth family. Only five to seven teeth are
Fig. 11. Close-up of specimen TMP 86.42.4, Fadenia uroclasmato sp. nov., showing the disarticulated dentition and
much of the symphysial tooth whorl in situ.
Fig. 12. Close-up of the symphysial tooth whorl of
specimen TMP 86.42.4, Fadenia uroclasmato sp. nov.,
describing a disrupted, but almost complete, circle.
TRIASSIC EUGENEODONTID SHARKS 21
visible. The weathered lateral teeth are very slender,
oblong and are conspicuously vaulted with their
highest elevation shifted towards the
distal shoulder.
Several skeletal elements of the anterior body
half are preserved: the neurocranium is seen in
ventral view with patches of elongated denticles
clustered in several distinctive areas. This shark
specimen was quite slender anteriorly, including
an oblong head and slender lower jaws. Accord-
ingly, the neurocranium is relatively slender
and elongate. Only the occipital region is well-
preserved and shows lateral processes situated far
posteriorly and a deeply cleft occipital process in
ventral view. The supraorbital rim of the neurocra-
nium appears to be located far posteriorly, roughly
in the vicinity of the preserved sclerotic rings
revealing a reinforced outer rim. The sclerotic
rings are solid and well-calcified, evidence of very
large eye-sockets and, thus, large eyes. The visceral
skeleton is partly calcified including the very
slender, oblong lower jaws and the left ?upper
jaw, which appears to be reduced to a small
element articulating with the posterior neurocra-
nium. Alternatively, it may be only partly-preserved
or partly-calcified. Branchial arches can be traced in
outline, due to preservation of pharyngeal teeth, and
they number at least five on either side. Poor evi-
dence of a sixth arch is present between arches 1
and 2 and underneath arch 1 of the right body
half. Several unidentifiable but well-calcified, bar-
shaped elements are preserved immediately in
Fig. 13. cf. Fadenia uroclasmato sp. nov., specimen UALVP 46526. (a) photograph and (b) line-drawing of the entire
specimen. (c) close-up of the partly preserved dentition, an asymmetrical lateral tooth family.
R. J. MUTTER & A. G. NEUMAN22
front of the fin region and are therefore interpreted
as the remainder of supporting elements of the pec-
toral girdle. Two partial fins with ceratotrichia and a
single basal cartilage are preserved. Despite their
strikingly different outlines, the preserved fins are
taken to represent the two pectoral fins, both con-
sisting of at least one dozen branched rays. Alterna-
tively, the more anteriorly situated fin may be
interpreted as a dorsal fin due to the ceratotrichia
being slightly re-curved at their tips. However,
branching ceratotrichia are not known to occur in
the dorsal fin of any other shark.
The dentition is heavily weathered and difficult
to interpret. There are at least two lateral tooth
families, one of which is clearly larger, centrally
vaulted and quite asymmetrical (Fig. 13c). The
extended shoulders of these larger teeth point ante-
riad. The teeth probably appear more asymmetrical
because they are heavily weathered and obliquely
embedded. These lateral teeth, however, taper
much more abruptly toward the distal (than
toward the proximal) shoulder of the crown. A
tooth family of much smaller and non-vaulted
teeth adjoin anteriorly. A number of tiny, blunt
teeth lacking a vaulted main cusp are preserved.
However, the state of preservation of those lateral
size and latero-distal teeth does not allow any
further assessment than that they formed a pave-
ment in lateral and distal positions.
Provisionally referred specimen: in specimen
TMP 87.42.11 (collected in C-cirque), the pectoral
fin also shows about 15 ceratotrichia, many of
which are distally branched. The base of the
pectoral fin is supported by a slender-triangular,
tripod-like structure that may be equivalent to
several, short, bar-shaped elements as preserved in
disarticulation in the holotype specimen.
Comparisons. This new species resembles speci-
men UALVP 38822 (þpart UALVP 46536
[Fadenia sp. indet.]) in overall anatomy of the pre-
served anterior postcranial region but the diagnostic
significance of these features is not currently settled
(see below and Fig. 13).
The caudal fin is intermediate in morphology
between the genus Caseodus and the (undescribed)
line drawing of a caudal fin of Fadenia crenulata
figured by Zangerl (1981, fig. 89D) following a
sketch drawn by S. E. Bendix-Almgreen (prelimi-
nary drawing erroneously attributed to E. Nielsen
[pers. comm. H.-P. Schultze, 2004]). The upper
lobes of the caudal fin differ in composition of the
supporting cartilages.
Fadenia sp. Figure 14.
Specimen. UALVP 38822 (þpart UALVP 46536),
46532, 47016 (from C-cirque and R-cirque).
Description. Specimen UALVP 38822 (þpart
UALVP 46536, superimposed view in Fig. 14)
comes from R-cirque (south wall) and consists of
several parts and counterparts collected separately
during several field trips. The pieces belong
undoubtedly to one individual and only differ in
degree of weathering. A composite sketch of parts
and superimposed counterparts is shown in
Fig. 14. Fadenia sp., composite photograph (a) and line-drawing (b) of several parts and counterparts superimposed as
preserved in specimen UALVP 38822 (þUALVP 46536). Major parts of the pectoral girdle are visible: the pectoral
fins, branchial arches, dermal denticles and unidentifiable cartilaginous ‘elements’.
TRIASSIC EUGENEODONTID SHARKS 23
Figure 14b. Some parts are heavily weathered but
show interesting features mainly as imprints of
cartilages and in situ pharyngeal teeth on the rem-
nants of the posterior visceral arches (ba3-5),
arranged in gently curved rows in the posterior
throat region. The structure of the pharyngeal
teeth/denticles is identical with those figured in
specimen UALVP 17936 (Eugeneodontida gen. et
sp. indet.). Some of the pharyngeal teeth on arch 3
look like the one displayed in Figure 22, with a pro-
minent central spike-like cusp and short lateral
cusps, whereas most of the other teeth show 7
slender-oblong cusps projecting from a well-
developed base. Slender and elongate, bar-shaped
visceral elements are scattered between the clusters
of pharyngeal teeth. Adjacent to what is interpreted
to have been the hyoid-visceral area, are four large
elements (one of which is very poorly preserved)
that must have represented parts of the shoulder
girdle. The two elements of the left pectoral fin
enclose a number of small, fragmentarily-preserved
elements but it is not clear whether they were frac-
tured post-mortem or actually represent small
elements close to the base of the pectoral
fin (Fig. 14b, ?pbas). The four large cartilages are
probably separate elements of the pectoral girdle
(basal and sternal cartilages). These elements are
roughly square, thin plates with rounded edges.
Two elements (pbas [1] and [2] in Fig. 14b)
that are larger than the slender, oblong and distal
ceratotrichia, are preserved adjacent to the basal
cartilage of the right pectoral fin (view as in
Fig. 14). Some of the ceratotrichia of both pectoral
fins are preserved with their proximal portions
intact. None of the ceratotrichia are jointed but
at least 5 distal radials of the right pectoral fin
are distally branched. The basal cartilage
of the left pectoral fin (view as in Fig. 14) is
fragmentarily-preserved but actually shows part of
the articulation with the enlarged proximal basal
cartilages (?pbas).
UALVP 47016. Figures 15–16. Specimen UALVP
47016 reveals numerous teeth including the tip of
a symphysial tooth crown. In overall morphology,
the remnants of the skull resemble Fadenia uroclas-
mato sp. nov. The slender tip is also reminiscent of
tips of teeth of Sarcoprion edax Nielsen, 1952 (plate
7) but the state of preservation does not allow ade-
quate comparison and assignment at the
species level.
Note: This specimen probably represents a new
species but its overall poor preservation does not
allow us to establish diagnostic features with confi-
dence (see Figs 15–16). Only two tips of symphy-
sial teeth are preserved partly as imprints and
these show almost smooth and laterally flattened
high-acuminate cusps (Fig. 16a). Mesial teeth are
moderately vaulted and distal teeth may lack promi-
nent labial buttresses altogether (Fig. 16b, c). The
dermal denticles preserved along with the cartilage
and the oral teeth, however, are reminiscent of case-
odontids, and this specimen is provisionally
assigned to Fadenia sp.
The specimen also shows the mid-portion of the
neurocranium (including the broad supraorbital
rim) and numerous ‘durophagous’ teeth on the
ventro-lateral margins. These teeth are fairly large
and lack a main cusp, sharing a very prominent
crenulation. The tooth whorl is not preserved but
Fig. 15. ?Fadenia sp.; a cranial portion associated with dermal denticles as preserved in specimen UALVP 47016. The
lower case letters refer to close-ups Figure 16a, b and c.
R. J. MUTTER & A. G. NEUMAN24
the scattered fragments of high-acuminate teeth are
almost perfectly smooth showing very few and faint
crenulations. Judging from the preserved fragments
of symphysial teeth, it appears they have a long,
slender and acuminate blade (tip), which is sagittal
in orientation and their ornamentation consists of
oblong, fine ridges running down the blade. The
precise outlines of none of these teeth can be
restored, because most exposed parts are broken
off. The majority of distal teeth are very long and
flat (Fig. 16c).
UALVP 46532. Specimen UALVP 46532 (Fig. 17)
is a relatively complete large pectoral fin tentatively
referred to Fadenia (see Discussion). This fin shows
the characteristic distal branching in the numerous
at least 19 ceratotrichia. In general, the mid-
portion of the anterior elements are broadest but
the ceratotrichia also broaden toward the distal tip
of the fin, where some of the radials fork just
before adjoining the border of the fin.
Caseodontidae gen. et sp. indet. Figure 18.
Specimens. TMP 88.98.100, ?TMP 86.154.94,
?TMP 95.114.8 (collected in C-cirque and
D-cirque).
Description. TMP 88.98.100: Specimen TMP
88.98.100 (from D-cirque talus along south wall)
is a disarticulated head region of a small, presum-
ably juvenile edestid which is not further identifi-
able. The cartilaginous remains represent the
neurocranium, rostrum and presumably, the upper
jaw, but details of respective cartilages could not
be assigned to specific skull elements. This speci-
men shows a series of distal teeth (Fig. 18), but
these are not readily comparable with those of
other specimens due to their small size and the pre-
sumably young age of the specimen.
Tentatively referred: Specimen TMP 86.154.94
(C-cirque from talus slope) is a portion of the post-
cranial skeleton showing a fin articulation that is not
further identifiable and TMP 95.114.8 (collected
from talus low below a fold containing Palaeozoic
to Lower Triassic rock) is an unidentified cranial
fragment with numerous and small durophagous
teeth that do not show any features that allow assign-
ment of the specimen to a lower taxonomic rank.
Superfamily Edestoidea Hay, 1930
?Family Edestidae Zangerl, 1981
Genus Paredestus gen. nov.
Type species. Paredestus bricircum gen. et sp. nov.
Diagnosis. See below.
Etymology. Par- (from Latin, meaning ‘to bring
forth’). The name Paredestus refers to the affinities
with the genus Edestus Leidy, 1855.
Paredestus bricircum gen. et sp. nov.Figure 19.
Holotype and single preserved specimen. UALVP
46579 (from C-cirque).
Etymology. Bri- (from Latin, meaning ‘short’) and
circ- (from Latin, meaning ‘wheel’), referring to the
small tooth whorl consisting of very few teeth.
Diagnosis. Very short symphysial tooth whorl with
teeth rapidly increasing in size; edges in symphysial
Fig. 16. Close-up of exposed teeth as preserved in
Fadenia sp., specimen UALVP 47016. (a) blades (tips)
of symphysial teeth; left blade as imprint, right blade
broken. (b) broken mesial teeth (arrow: note the vaulted
central portion of the crown). (c) flat distal teeth.
TRIASSIC EUGENEODONTID SHARKS 25
teeth possibly serrated; roots of symphysial teeth
directed posteriad; mesial teeth with variably and
moderately vaulted cusp; oblong pavement teeth are
blunt showing a pronounced longitudinal crest.
Description. The partial jaw UALVP 46579
(Fig. 19) shows very informative views of the sym-
physial tooth whorl in the lower jaw and the adja-
cent tooth files presumably mesio-lateral teeth.
The former teeth show the general arrangement
characteristic of tooth whorls arranged in a half-
circle, sharing the site of root attachment and appar-
ently completely fused roots. As far as visible (parts
of the teeth are covered by other teeth and a sha-
green of denticles), the tooth crowns of teeth in
the tooth whorl are largest proximally and smallest
towards the anterior tip of the lower jaw. The roots
are poorly-preserved and the crowns are partially
fragmented but intact. The crowns are broad but
acuminate and are clearly delimited from the
joined roots, although swinging gently posteriad
with the basally expanded portion. Although imper-
fectly preserved, weathered and partly covered, the
crowns clearly show a rounded lateral wall in lateral
aspect and the second hindmost preserved tooth of
the tooth whorl shows a serrated sagittal edge
above the posterior ‘saddle’ of the root. It appears
that the serration in the second tooth from the
right is due to weathering (see Fig. 19c).
The roots on the symphysial teeth are broken off
and poorly preserved but appear to have extended
posteriorly at an oblique angle to the axis of the
tooth crown as is common in edestids.
In contrast to the teeth of the tooth whorl that
show entirely smooth tooth crowns, teeth of the
mesial tooth files are unicuspid teeth with a con-
spicuously broadened middle portion (or cusp)
with a more or less blunt apex and extensive crenu-
lation (Fig. 19). One sagittal and one transverse
crest respectively divide these teeth into four dis-
cernible sectors, and numerous crenulations, partly
branching, run down the apex. The transverse
crest is faintly but better developed than in symphy-
sial teeth. A large number of flat teeth lacking main
cusps but showing prominent crenulations and a
pronounced longitudinal crest are distributed over
the slab and seem to have represented a pavement
dentition lining the ventral wall of the neurocra-
nium or an (unpreserved, ?cartilaginous) upper
jaw element merged with the neurocranium,
against which the symphysial teeth may have
abraded. As far as discernible, the crown ornament
is much more prominent on the labial wall of the
crowns than on the lingual wall. In addition to the
numerous (?upper) pavement teeth, there are at
least two additional tooth families with
enlarged teeth.
Comparisons. The mesial and lateral teeth pre-
served along with the symphysial teeth show little
affinities with other known eugeneodontid denti-
tions but the overall pattern in dental morphology
and variation is remotely similar to a number of
Fig. 17. Photograph (a) and sketch (b)of?Fadenia sp., pectoral fin of specimen UALVP 46532. Note the distally
branched (anterior and posterior) ceratotrichia (cer).
Fig. 18. Caseodontidae gen. et sp. indet., specimen
TMP 88.98.100. Gently vaulted, long distal teeth
in lingual view.
R. J. MUTTER & A. G. NEUMAN26
other edestoids. The central vaulting of teeth, inter-
preted as being mesial, is reminiscent of the genus
Agassizodus St. John & Worthen, 1875. The mor-
phology and root orientation, however, are interpre-
tive due to the poor preservation and the crowns
show similarity with the edestid Helicampodus
Branson, 1935 and Sinohelicoprion Zhang, 1976
(which may be closer to Helicampodus; see
Chang & Miao 2004) in outline and gross mor-
phology. With reservation, the latter taxon may
therefore also be alternatively placed within Edesti-
dae Jaekel, 1899 (sensu Zangerl 1981). The pattern
of a half-circle symphysial tooth whorl abrading
against upper pavement teeth in Paredestus
bricircum gen. et sp. nov. is also reminiscent of
Sarcoprion edax Nielsen, 1952.
Eugeneodontida gen. et sp. indet.
Figures 20–26.
The specimens have been collected in C-cirque
(except for TMP 89.127.43 [D-cirque]), but do not
allow assignment to any recognized species.
Fig. 19. (a) photograph and (b) line drawing of Paredestus bricircum gen. et sp. nov., specimen UALVP 46579. Note
the teeth in the symphysial tooth whorl decrease in size rapidly anteriad. (c) close-up of the partly preserved symphysial
tooth whorl. Arrow points anteriad.
TRIASSIC EUGENEODONTID SHARKS 27
Description.
TMP 86.42.2: This specimen (TMP 95.118.1 is part
of the same individual) is preserved in several parts
and counterparts in ventral view and its estimated
standard length is about 1 m (Fig. 20). The large
slab shows major, disarticulated elements of the
rostrum and the visceral skeleton associated with
a partial fin in part and counterpart (the presumed
dorsal fin does not necessarily belong to the same
specimen and hence is not shown in Fig. 20). This
dorsal fin resembles specimen TMP 89.131.2 (see
Fig. 20. (a) photograph and (b) sketch of specimen TMP 86.42.2 (þTMP 95.118.1; Eugeneodontida gen. et sp. indet.);
parts of the visceral skeleton associated with the neurocranium. The counterpart TMP 95.118.1 was discovered 10 years
after collection of TMP 86.42.2 in the same slope of C-cirque and shows nicely disarticulated elements in fine
preservation. The lack of dental remains prevents more definite assignment and comparison with other eugeneodontids.
Fig. 22. Eugeneodontida gen. et sp. nov., anterior view
of flattened and weathered, raker-like teeth with broad
and spike-like extended central cusp as preserved in
specimen UALVP 17937.
Fig. 21. Isolate patches of dermal denticles (and
pharyngeal ‘teeth’) as preserved in Eugeneodontida gen.
et sp. indet. (a) specimen UALVP 22108 (type I
denticles): these denticles occur quite spaced and similar
lepidomorial scales cover large areas. (band c),
specimen UALVP 17936 (type II denticles): these
denticles, visible in ventral view, were probably
pharyngeal teeth or gill-raker like teeth found only in the
gill area (b ¼anterior view; c ¼posterior view).
R. J. MUTTER & A. G. NEUMAN28
below: ‘Specimens showing fin girdles and fins’) in
having similarily arranged ceratotrichia. The
imprints of anterior neurocranial ‘projections’ of
the neurocranium are reminiscent of Caseodus sp.
(see Zangerl 1981, fig. 84B, C). The disarticulated
head and visceral region can, at present, not be
unambiguously interpreted and we were unable to
identify some of the elements preserved as vague
imprints due to lack of suitable comparative
material. The preserved parts clearly show sym-
metrical arrangement of rather small and ridged
elements, triangular or rectangular in outline, that
are suggestive of parts of calcified visceral carti-
lages (mandibular and hyal elements).
UALVP 22108. Specimen UALVP 22108 (Fig. 21a)
shows reasonably well-preserved denticles (‘type
I’). The state of preservation of the denticles does
at present not allow to recognize distinctive features
(see ‘Discussion’ below). The multiple lepidomor-
ial scales (sensu Stensio
¨1962) displayed using
this specimen are quite uniform and flat, and they
cover major parts of the body as is seen in various
other specimens.
UALVP 17936. Specimen UALVP 17936
(Fig. 21b–c) shows favourably preserved ‘pharyn-
geal teeth’ (denticles ‘type II’) in sharply delimited
areas originally probably covering much of the
branchial arches. Type II–denticles (or pharyngeal
teeth/denticles) are seemingly more variable
among specimens but depending on their orien-
tation, these denticles may look quite different in
anterior (Fig. 21b) and posterior view (Fig. 21c).
Type II–denticles are easily identified by the 6 8
Fig. 23. Eugeneodontida gen. et sp. indet., tooth ultrastructures as preserved in an isolated tooth in specimen TMP
98.127.43. (aand b, close-up), tooth basis (bs) and crown (cr) histology is predominantly osteodont (developed as a
tubular pulp cavity, tpc) with an apically restricted band of orthodentine (od) reaching into the enameloid layer (el). (c
and d, close-up; section etched 5 seconds in 5% HCl), the thick tooth enameloid is composed of cross-bundled fibres of
slender crystals in well-defined orientation.
Fig. 24. Eugeneodontida gen. et sp. indet., sketch of the
basal cartilage and the dorsal fin of specimen UALVP
17928.
TRIASSIC EUGENEODONTID SHARKS 29
Fig. 25. Eugeneodontida gen. et sp. indet. (a) Photograph and (b) sketch of the relatively large, weathered ?pectoral
girdle elements as preserved in specimen UALVP 31751.
Fig. 26. Eugeneodontida gen. et sp. indet. (a) photograph and (b) sketch of imprints of a portion of probable caudal fin
as preserved in specimen TMP 95.118.2.
R. J. MUTTER & A. G. NEUMAN30
long and acuminate cusps radiating from the basal
plate which bulges out anteriad and posteriad, and
which is apically re-curved. The central cusps
may be considerably extended in some specimens
but the evidence also suggests that the excessive
length of the central cusp may be due to embedding
and preservation in favourable aspect, because the
denticles’ morphology may look strikingly different
when flattened, weathered or seen in different views
(compare also specimen UALVP 17937 [Fig. 22]).
TMP 89.127.43: A thin section through the crown
shoulder of an isolated mesio-lateral tooth (TMP
89.127.43 (Fig. 23) reveals that the root is larger
than the crown and highly vascularized. The
crown is oval-shaped in cross-section, consists of
tubular pulp cavities (tpc), orthodentine (od) enter-
ing the enameloid (el) and an outermost thin layer
of apical vitrodentine (vd; according to terminology
of Zangerl 1981). The enameloid-vitrodentine layer
is much more thickly developed apically than on the
crown shoulders but covers the entire crown.
Tooth histology in eugeneodontids is hence
apparently primitive in being osteodont with a dis-
tinctly restricted apical band of orthodentine pene-
trating the enameloid layer. The thick tooth
enameloid is composed of cross-bundled fibres of
slender crystals in irregular but well-defined orien-
tation (Fig. 23c, d). The thin apical layer we identify
here as Zangerl’s vitrodentine, has been considered
synonymous with the enameloid layer by Bendix-
Almgreen (1983).
Specimens showing fin girdles and fins
The fin in specimen TMP 95.118.1 has ceratotrichia
reminiscent in organization but slightly smaller in
number than specimen TMP 89.131.2. Both speci-
mens represent portions of dorsal fins. Specimen
UALVP 17928 shows an almost completely pre-
served dorsal fin and its supporting cartilage
(Fig. 24). The cartilage supporting the fin is only
partly preserved but is clearly deeper than long.
There were at least 22 ceratotrichia, of which
most are preserved as imprints. The rays are all
gently curved, increase in width posteriad and
taper to a point. The anterior rays are all re-curved
whereas the more posterior ones are rather
s-shaped.
Specimen UALVP 31751 (Fig. 25) shows the
weathered scapulocoracoids of both halves of the
pectoral girdle, seen in lateral (external) view and
an additional, unidentified cartilage beside the
right scapulocoracoid. The slender scapulocora-
coids are sickle-shaped and have an acuminate
apical tip. The apical portion appears most
thoroughly calcified with a prominent thick anterior
border. The middle and distal portions are slightly
detached from each other and this may indicate
originally poor calcification. The middle portions
share postero-external surfaces developed as
thickened rims that probably served as articulation
sites for the pectoral fin’s basal cartilage and its
radials. The distal portions are thin cartilages and
are very weakly-calcified. Scattered in-between
the elements are small to tiny shreds, fragments
and imprints of additional, unidentifiable cartilages.
Specimen UALVP 17930 is probably a fragment
of the central portion of the main shoulder girdle
element, the scapulacoracoid but this element and
the following specimens can not be more precisely
identified at present. Specimen TMP 86.154.94 is a
portion of the postcranial skeleton showing a fin
articulation and TMP 2001.15.03 is part of a
caudal fin.
Specimen TMP 95.118.2 (Fig. 26; collected from
middle of C-cirque directly below quarry) shows
imprints of the lower lobe of a partially preserved
caudal fin, associated with smeared shagreens of
dermal denticles. At least 7 ceratotrichia and
2-calcified cartilages are preserved as imprints, the
surface is largely broken or weathered. The most
proximal element is slender, oblong and abuts (with
its knob-like head) the proximal, concave face of
the distally adjoining second cartilage. The latter
element has the shape of an arched rectangle and
articulates distally with at least 7 extremely slender
rays, composed almost entirely of prismatic cartilage.
The ?anterior rim is delimited by several (only partly-
preserved)narrow ridges, also consistingof prismatic
cartilage. Beside these elements, there are also a
number of more fragmentary cartilages preserved
immediately posterior to the large cartilages (basal
elements?), but their outlines and shapes are too
poorly-preserved to allow identification.
The dermal denticles are minute, often smeared
or broken but the smallest ones are rounded or
diamond-shaped in outline, flat and bear several
(4–7) antero-posteriorly running ridges. Slightly
larger, thicker denticles with entirely smooth sur-
faces are also present.
?Eugeneodontida gen. et sp. indet. The following
specimens are tentatively referred to eugeneodon-
tids. Specimen UALVP 46684 probably represents
the snout tip of a rostral cartilage of a shark, poss-
ibly an edestoid. Thin section through the posterior-
most portion reveals the prismatic cartilage only,
not associated with dermal denticles. However, on
the same slab is an edestoid tooth fragment associ-
ated with coelacanth remains (scale and fin ray).
Specimen TMP 95.114.8 is a cranial fragment
with numerous ‘durophagous’ teeth that do not
show any features that allow assignment to a recog-
nized group. However, the blunt crown morphology
and their large number clearly suggest eugeneodontid
TRIASSIC EUGENEODONTID SHARKS 31
affinities, although many teeth are almost completely
buried in matrix in various views.
Specimen UALVP 46533 shows the distal
portion of a partial ?pectoral fin. The tips of the 3
ceratotrichia taper distally and there are narrow
gaps in between as in other specimens referred to
eugeneodontids (see above).
Specimen TMP 89.131.2 (collected from talus in
C-cirque) appears to be a dorsal fin as it possesses at
least 21 slender ceratotrichia, each one progress-
ively thickening in width posteriad while tapering
distally. They are all jointed ventrally by the
dorsal cartilage. The specimen is badly weathered
and is mainly preserved as an imprint. The scales
are badly weathered and smeared but both types
of denticles observed are comparable to specimen
TMP 95.118.2.
Description in open nomenclature
Eugeneodontida gen. et sp. indet. (unnamed
eugeneodontid, Fig. 27).
Specimen UALVP 46539 (from C-cirque): This
specimen is part of a thick slab of brownish weath-
ered, compact siltstone with a partial, disarticulated
dentition showing many partially preserved teeth
and their peculiar features in various aspects. The
labial side of some lateral teeth has about a dozen
very pronounced large ridges (Fig. 27a), whereas
the lingual side shows a much more shallow
ornament that is distantly reminiscent of tooth
crowns of acrodontids (Fig. 27b). No conspicuous
longitudinal crest along the tooth shoulder is devel-
oped. The visible teeth range in length from a few
millimetres to about 25 mm. The large lateral
teeth are highly ornamented lingually, whereas
distal teeth are asymmetrical and almost devoid of
any ornament.
Comparisons. The range of tooth variation in this
specimen is close to that observed in Caseodus
varidentis sp. nov. but the significance and variation
in lower v. upper dentitions is not known in any
other eugeneodontid taxon and we therefore
refrain from assigning this specimen to the
same taxon.
This specimen also stands out in its type of pres-
ervation. The teeth are widely scattered across the
bedding plane on top of this single (approximately
15 cm thick) siltstone slab suggesting a different
postmortem depositional history than all other
eugeneodontid specimens recovered to date from
Wapiti Lake.
Discussion of comparisons with
described taxa
Dentitions and teeth
Eugeneodontid taxa reported from the Induan
Olenekian of Wapiti Lake display an astonishing
diversity. These new specimens exhibit body sizes
comparable to some of the latest Palaeozoic
members of that group, and suggest eugeneodontids
may have represented some of the largest marine
predators during the Early Triassic. This contrasts
with the occurrence of dwarfism during the
marine Early Triassic – occurring in vertebrates
and invertebrates (Wignall & Benton 1999;
Twitchett 2001; Hautmann & Nu
¨tzel 2005; Mutter
2005). However, compared to their Palaeozoic pre-
decessors, the tooth whorls of these Triassic forms
are only of moderate size and often half-circles
(not spiral-shaped, cf., e.g., spirals of Helicoprion
Karpinsky, 1899), suggesting that differing
feeding adaptations prevailed among the Early
Mesozoic members.
The actual extent of reduction of the upper jaw
in Late Palaeozoic caseodontids has been suggested
by Zangerl (1981). It is not clear what role the poss-
ible upper jaw elements played in eugeneodontids,
and there is currently no unequivocal evidence of
a completely-calcified upper jaw of the length of
the lower jaw in any eugeneodontid specimen
from Wapiti Lake. Caseodus varidentis sp. nov.
and Paredestus bricircum gen. et sp. nov. yield
evidence of partial in-situ tooth files that are most
Fig. 27. Unnamed eugeneodontid (possibly a
caseodontoid), specimen UALVP 46539. (a) smaller
distal tooth crown in occlusal view with a smooth labial
wall. (b) fragment of a larger lateral tooth in
lingual view.
R. J. MUTTER & A. G. NEUMAN32
parsimoniously reconstructed as located in an upper
jaw element. However, we are unable to identify
additional jaw cartilages in this position. The
anterior upper jaw was probably adapted to accom-
modate the modified jaw action using the lower jaw
symphysial dentition in a specialized feeding strat-
egy. In contrast, the lateral and distal posterior
(lower and upper) jaw regions were well adapted
to durophagous feeding habits. The variable
degree of calcification in these remains does to
some degree support the view of Zangerl (1981)
that the lack of preserved skeletal remains in Late
Palaeozoic forms could be due to lack of calcifica-
tion, but we find no support for an evolutionary
process favouring loss of calcification towards the
end of the Palaeozoic. It is likely that partial calci-
fication of head and anterior skeleton was also
imperative for functions of jaws and associated
levers in support of the presumed partly duropha-
gous feeding habit. It is unclear whether the
absence of anterior jaw elements is due to fusion,
loss or lack of calcification (or a combination of
these states) in the eugeneodontids studied here.
The assessment of individual tooth variation
within a single lower v. upper tooth family or
entire jaw dentition is problematic. However, it
seems that heterodonty has previously been
greatly underestimated. For instance, teeth of the
same specimen show varying degrees of crown
ornamentation, development of buttresses, tooth
size, angle between crown shoulders and complex
crown morphology.
The central vaulting in mesial teeth may have
diagnostic significance in addition to, or even
instead of, a ‘smooth lingual wall’ (cf. Zidek
1976). Paredestus bricircum gen. et sp. nov. (speci-
men UALVP 46579) remotely resembles Edestus
giganteus Newberry, 1888 (specimen AMNH 225)
in overall morphology of the tooth crown. Tooth
file curvature is stronger in the crown in the
former taxon and edges and roots are poorly pre-
served. In Paredestus bricircum gen. et sp. nov.,
the anterior teeth in the file are strikingly small
but the curvature and size of the tooth whorl see-
mingly rules out the specimen being a juvenile indi-
vidual. Unfortunately, the only cranial material
available for comparison with the material
described here is Ornithoprion hertwigi Zangerl,
1966. Cranial morphology of the latter species
does not match the cranial morphology of the new
specimens: the jaws of this species are particularly
massive, long and peculiarly shaped.
The postulated synonymy of Campodus de
Koninck, 1844 and Agassizodus St. John &
Worthen, 1875 (hinted at by Zangerl 1981, p. 77)
cannot yet be resolved. In contrast, specimen
TMP 86.42.3 further complicates the matter by
providing evidence for intradental variation in
Caseodus with the upper jaw dentition lacking
lingual crenulations, considered to be typical for
the genus Campodus. However, teeth assigned to
Campodus do show other assumingly diagnostic
features that distinguish this genus from all other
eugeneodontids: the coarse ridges bulge out on
both lingual and labial walls, all teeth are remark-
ably uniform (AMNH 8853) and rather Orodus-like
in lingual and labial outline.
The holotype of Campodus variabilis is a pur-
ported ‘symphysial row of teeth’ from the Upper
Carboniferous Coal Measures of Cedar Creek,
Nebraska (USA). Remarkably similar teeth occur
in mesial or near symphysial position in the holo-
type of Caseodus varidentis sp. nov. (although the
crown shoulders in these teeth enclose a much
greater angle) and these teeth belong in the same
dentition together with completely differently
shaped lateral teeth.
Unfortunately, only a few teeth of Fadenia have
been found and are described here but, neverthe-
less, the new caseodontid Caseodus varidentis sp.
nov. clearly reveals affinities in its dentition to the
former genus. For instance, the large lateral teeth
of Fadenia gigas Eaton, 1962 from the Lower
Pennsylvanian of the Upper Cherokee Shale
(Lexington Coal) in Lucas (Henry County,
Missouri, USA), come close in overall morphology
to the respective tooth file in the holotype of
Caseodus varidentis sp. nov.
Variation in the dentition found in Caseodus
varidentis sp. nov. holotype specimen TMP
86.42.3 is comparable in range to the variation in
Fadenia crenulata as illustrated by Nielsen (1932,
pls 2-6), although teeth of the former species
show more extensive crenulation. Crowns of
Fadenia crenulata are less massively developed
linguo-labially and have less extremely vaulted
central cusps in lateral tooth files.
The slant of the root and lower portion of the
crown in Paredestus gen. nov. are of ambiguous
morphology but of crucial importance with
respect to the genus’ systematic position. The orien-
tation of the root is interpretive (namely posteriad)
and not similar to other geologically young taxa
such as the agassizodontid Sarcoprion edax
Nielsen, 1952 (see below). The symphysial teeth
are broad but less widely separated than in
Edestus Leidy, 1855. In Edestus heinrichi New-
berry & Worthen, 1870 the teeth are similar in
being closely positioned but differ greatly in many
respects, including shape of the tooth crown. The
orientation of the root slant and the affinities of
this genus to both superfamilies of edestoids are
therefore interpreted with caution. In edestoids, no
similar-sized mesial and lateral teeth beside the
tooth whorl are known and all other teeth in the den-
tition are of pavement-type and much smaller than
TRIASSIC EUGENEODONTID SHARKS 33
teeth in the tooth whorl (see also Nielsen [1952]
below). All previously described edestoids are
quite unlike Paredestus gen. nov. in this respect.
Helicampodus kokeni Branson, 1935, Lestrodus
Obruchev, 1953, Helicoprion (see Bendix-
Almgreen [1966] and Zangerl [1981]) and various
other ‘true’ edestids match the crown morphology
and possibly the root organization by pointing
posteriad (Fig. 19), but differ in lower crown
morphology and in being more tightly joined. The
‘helicoprionid’ fragmentary tooth whorl, ‘Sinoheli-
coprion’ (cf. Helicampodus)qomolangma Zhang,
1976 (the only other unquestioned Early Triassic
eugeneodontid) from western China, looks remark-
ably similar to the abovementioned four taxa and its
taxonomic status is in need of re-assessment
(see also Chang & Miao 2004). Some of the poorly-
preserved eugeneodontid tooth crowns such as the
one in specimen UALVP 46539 (described here in
open nomenclature), come close to ‘Sinohelicoprion
(cf. Helicampodus)Qomolangma (Zhang 1976).
Nielsen (1952) described various edestoids from
the Upper Permian Wordy Creek Fm of East Green-
land, but except for Fadenia crenulata, none of the
edestoids closely resemble the material recovered
from Wapiti Lake. In fact, we have found no
evidence of agassizodontid edestoids. This is
surprising, as the Greenland eugeneodontids are
stratigraphically close to the Wapiti Lake sample.
In particular, no agassizodontid remains compar-
able in root morphology to Sarcoprion edax
Nielsen, 1952, and represented by several speci-
mens from Greenland, can be positively identified
in the Wapiti Lake sample. The edestid Paredestus
bricircum gen. et sp. nov. comes close in symphy-
sial and anterior tooth file morphology but unam-
biguously possesses enlarged mesial teeth, too.
As discussed above, some of the features that are
believed to be diagnostic for eugeneodontid teeth
are probably linked to functional needs and the pos-
ition of the teeth in the dentition. For example, we
identify as such the strong buttresses combined
with smooth crown surfaces both in labial and in
lingual walls respectively in upper jaw teeth of
Caseodus varidentis sp. nov. Also, the varying
angle between the tooth crown shoulders in sym-
physial and mesial teeth of the same species and
the general dissimilarities in tooth crowns in
upper and lower jaws of eugeneodontids prevent
us from reconstructing dentitions with confidence.
It seems likely that some isolated tooth files
described in the literature as ‘symphysial tooth
whorls’, may in fact be near-symphysial
(¼mesial) tooth files in the symphysis of the
lower or the upper jaw. ‘Genuine’ symphysial
tooth whorls are always found anterior to these
symphysial teeth and often on an extended or separ-
ate rostral cartilage adjoining the lower jaw
symphysis. The distance between the lower jaw
symphysis and the tooth whorl may differ consider-
ably between eugeneodontid taxa, and isolated
tooth whorls should ideally be preserved on the
rostral cartilage or as near-complete tooth batteries
to be justifiably identified as such. In at least some
caseodontoids such as Caseodus or Fadenia, the
mandibular rostrum may be reduced or absent
and/or tooth whorls may be flanked by transitional
mesio-symphysial tooth files. It is also conceivable,
that agassizodontid edestoids such as Sarcoprion
and Agassizodus differ in lacking the mesial/sym-
physial tooth type found in the lower jaw symphysis
of caseodontoids, because teeth of the tooth whorl
in the former taxa are greatly enlarged if compared
to all other tooth types found in the same dentition.
Cranial and postcranial skeleton
Zangerl (1966) reconstructed Ornithoprion hertwigi
with six gill arches but in 1981 he revised his recon-
struction of the gill basket to having only five
arches. The evidence from Wapiti Lake eugeneo-
dontids is also unclear in this respect and there
may have been a sixth gill arch preserved beneath
the first ray in Fadenia uroclasmato sp. nov. even
though we can see only five gill arches clearly
developed in specimen UALVP 46526 (Fig. 13).
This alternative interpretation would also be sup-
ported by the large gap between neurocranium
and shoulder girdle (cf. Zangerl [1979, p. 457]).
Pectoral fins are preserved in several of the
specimens in association with remains of Fadenia
but there is also an isolated fin (Figs 14, 17). All
are assigned to Fadenia primarily on the basis of
the branching ceratotrichia (cer). This feature is
highlighted by Bendix-Almgreen (1976) and listed
by Zangerl (1981) as diagnostic of Fadenia.
However, Bendix-Almgreen (1975b) showed that
distally forked rays and similarly organized pectoral
girdles also occur in other, not closely related
groups of sharks including several species of
Cladoselache. However, the branching occurs in
Fadenia in posterior and anterior rays, and the
branching in anterior rays is not known in any
other shark.
Dermal denticles
There are three different kinds of denticles found in
the eugeneodontids from Wapiti Lake, each showing
a varying distribution and abundance. The denticles
located in the posterior head region consist of a
single ?anteriorly projecting cusp that do not
resemble any other denticle currently known (see
inset Fig. 2). The second kind of denticles are of
‘classic’ lepidomorial shape (single or multiple
elements; primary and secondary sensu Stensio
¨
R. J. MUTTER & A. G. NEUMAN34
1962). These ‘type I’ denticles appear in many body
regions, are abundant, and resemble a general type of
lepidomorial aggregate found in many chondrichth-
yans that are not closely related such as Eugeneodus
Zangerl, 1981 and Orodus Agas
´z, 1844 (see
Fig. 21a; compare Zangerl 1981).
The third kind of denticles (see Fig. 21b, c
and Fig. 22, ‘type II’ denticles) have not been
described previously in eugeneodontids. They are
pharyngeal or raker-like-teeth (or specialized denti-
cles) apparently sitting on and restricted to
visceral elements.
Conclusions
The youngest record of eugeneodontid
sharks
The remains described here are the first articulated
eugeneodontids recovered from any Triassic strata
and likely represent one or several assemblages
possibly spanning a few million years in time
(Induan–Olenekian; early Smithian [possibly
Griesbachian] to Spathian). Few of the specimens
were recovered in situ but there is convincing
evidence (from data collection and lithology) that
all specimens weathered out of Lower Triassic
(not Upper Palaeozoic) rock. For instance, conodont
samples of late Induan and early Olenekian
(Dienerian to Smithian) ages were taken from the
same area where specimen TMP 2001.15.03 was
found, and specimen TMP 89.127.43 was collected
high in the talus of D-cirque, in which locality
there are no Palaeozoic rocks present in the
overturned section.
Several lineages of eugeneodontids hence sur-
vived the end-Palaeozoic crisis and are recovered
in astonishing diversity from the Vega-Phroso Silt-
stone Member at Wapiti Lake. Helicoprionid-type
spirals and agassizodontids, widely spread in the
Permian, are apparently absent from this assem-
blage. All species are of similar body size to their
latest Palaeozoic relatives. However, the current
state of eugeneodontid taxonomy and systematics
is still unsatisfactory. The present paper adds
to an already biased picture, in which most
species and genera are almost exclusively known
by fragmentary dental remains, and the genus
Fadenia yields information based predominantly
on non-dental material.
Many skeletal elements cannot yet be identified
and assigned to a distinctive species because of the
lack of adequate comparative material and because
the taxonomic significance of differences in dental
v. skeletal features cannot yet be assessed. More
complete specimens are needed to improve the
current taxonomic concept.
A wide variety of eugeneodontid dentitions
evolved in the Late Palaeozoic. However, the fact
that almost all taxa are established on the basis of
very fragmentary material must not be underesti-
mated. As outlined above, the probable dental vari-
ation present in lower v. upper jaws and the
individual, intraspecific and interspecific variation
in teeth is just beginning to be explored.
Teeth preserved in partial view and reported ‘fea-
tures’ in isolated material must be interpreted with
caution. In general, features in teeth, other than sym-
physial tooth whorls and mesial teeth, presumably
bear less diagnostic significance. The entire tooth
battery may show a strikingly different organization
in different taxa but such assessment must await the
discovery of more completely articulated dentitions.
According to the present taxonomic concept and our
study, a wide variety of dental ‘architectures’ may
indeed have existed in spite of a comparatively
uniform postcranial skeleton. The pectoral girdle is
apparently variably developed and may consist of
broad plates and slender-oblong scapulocoracoids
(cf. Figs 9, 13, 14 and 25). The caudal fin skeleton
appears to yield diagnostic features in the degree of
fusion of haemapophysial v. neurapophysial
elements in caseodontids. Unfortunately, this infor-
mation has not yet been seen in association with
differences established on the basis of diagnostic
dental features.
The fact that none of the specimens recovered
from Wapiti Lake can be referred to previously
described species reflects the incompleteness of
the group’s fossil record across the Permo-Triassic
boundary and also evokes important corollaries on
future taxonomic work. First, a re-investigation of
the most completely preserved dentitions is
needed to establish diagnostic features. Second,
crania should be examined closely, because it is
likely that eugeneodontids possessed, among other
characters, either a relatively broad or a slender
skull together with differing types of dentitions
(cf. e.g. Figs 2 and 13). Third, caudal fin skeletons
add to our knowledge in only a few species. This
area may contribute significantly to the improve-
ment of diagnoses, despite the generally assumed
absence of diagnostic features in the postcranium
(see also Zangerl [1981]).
Dental variation, jaw reconstruction and
jaw suspension
Due to the rarity and fragmentary state of preser-
vation of eugeneodontid sharks, almost all aspects
of dental variation, including monognath or
dignath heterodonty, individual, intraspecific and
interspecific variation and upper jaw anatomy, are
poorly known. According to this study, major
TRIASSIC EUGENEODONTID SHARKS 35
differences can be expected to occur in the arrange-
ment and morphology of upper and lower jaw den-
tition in eugeneodontids. The most complete
dentition of Caseodus varidentis sp. nov. (in holo-
type specimen TMP 86.42.3) shows striking discre-
pancy in degree of tooth surface crenulation
(ornament) in upper and lower dentition. The
upper jaw can be traced in radiographs of Caseodus
basalis and Eugeneodus richardsoni (see Zangerl,
1981, fig. 32) and appears to be anteriorly reduced
yet firmly attached to the neurocranium. Zangerl
(1981; p. 26) refrains from using the term
‘hyostylic’ and suggests the caseodontoid condition
is derived, but in a different way than in neosela-
chians. Following Zangerl’s (1981; p. 2426)
interpretation of upper jaw morphology and jaw
suspension, the lower symphysial tooth whorl
would actually not act against teeth of the palato-
quadrate but against teeth of an additional anterior
cartilage in the upper jaw or against teeth embedded
in the ventral surface of the rostral tip of the neuro-
cranium. Fadenia uroclasmato sp. nov. may have
upper jaws not fused with the neurocranium
(compare Fig. 9). The holotype specimen TMP
86.42.3 of Caseosus varidentis sp. nov. suggests
that relatively large mesial teeth occur in the
upper dentition immediately behind the tooth
whorl but we currently lack enough information
on upper jaw structure in Caseodus varidentis sp.
nov. to comment on the reconstruction provided
by Zangerl (1981). Further study of the internal
structure of the skull of TMP 86.42.3 may reveal
in more detail how the caseodontoid jaw suspension
was constructed.
In any case, the generally accepted reconstruc-
tion of the upper jaw/tooth whorl as a functional
‘tin-opener’, suggests a solid (dental) anatagonist
for the lower jaw symphysial tooth whorl. As
outlined in the Discussion, we can only assume
upper jaw elements were either absent, weakly cal-
cified (thus, not preserved) or firmly integrated into
the neurocranium.
Implications for the end-Permian extinction
event and palaeobiogeographic
considerations
The Permo-Triassic boundary has long been held as
the turning point in environmental history due to
magmatic events, palaeoclimatic change, seawater
isotope changes, magnetic polarity shift and pro-
posed biota extinctions (e.g. Veevers et al. 1994).
The discovery of this group of elasmobranchs in
surprising diversity in the open marine Early
Triassic is set against this global picture. While
many marine clades dwindled or became extinct
towards the boundary, the presence of
eugeneodontids in the Early Triassic of western
Canada in relatively high diversity suggests this
group was much less affected by the major environ-
mental turning point than previously believed.
Investigation and comparison of Parahelicampodus
spaercki Nielsen, 1952 and Fadenia crenulata
Nielsen, 1952 from Kap Stosch, East Greenland,
and ‘cf. Helicampodus qomolangma’ (Zhang,
1976) from Dingri (Xian County), should be the
next, highly valuable studies to further explore
this phenomenon. There is no sign of extinction or
decrease in body size of the group as a whole: it
has been suggested this would have occurred
during the recovery phase due to dwarfism
(Twitchett 2001) and has recently been shown for
an isolated group of stem actinopterygians (Mutter
2005) and was documented in clams (Hautman &
Nu
¨tzel 2005). Although the evidence does not
yet allow precise assessment of relative diversity
of this particular group during the entire Permo-
Triassic turnover, these new findings support the
view that the marine end-Permian extinction event
was highly selective.
Palaeonisciform fishes are also represented by
several isolated lineages in the Triassic (Mutter
2003), and some other fish groups do not conform
with the end-Permian extinction scenario. For
example, actinistia may or may not peak in diversity
in the Early Triassic (compare Forey 1998 and
Schultze 2004). Although it is true for many fish
groups that a major faunal change took place
across the Permo-Triassic boundary, we lack accu-
rate dating for many of these fossil sites and are still
unable to trace and reconstruct the events leading to
faunal turnover in a temporal sequence during the
Early Triassic. Establishing reliable time-control
is essential for understanding and reconstructing
relevant historic events.
The reconstruction of outlines of Pangaean ‘sub-
continents’ and borders of Triassic marine habitats
and their interconnections is problematic,
eventhough continental plate movements following
the break-up of the super-continent Pangaea (at the
beginning of the Jurassic) are fairly well under-
stood. It is generally assumed that (according to
the theoretical computer fit, in which the relevant
coastlines of today’s continents are displayed to
match perfectly) there were no apparent seaways
present, for instance, between the Americas and
Africa or that there was no passage between the
Proto-Atlantic and the west coast of central
America connecting marine realms of the southern
and northern hemisphere. The fact that we find
similar faunal assemblages in both hemispheres
(‘cosmopolitan’ taxa) very early in the Triassic, is
normally explained as rapid dispersal events in
impoverished habitats following the great extinc-
tion event (recovery process). Palaeoichthyology
R. J. MUTTER & A. G. NEUMAN36
is capable of providing important contributions to
more accurate delineation of ancient coastlines,
because fish fossils are ubiquitous and often ident-
ifiable once a taxonomical framework is in place.
In addition, certain Late PalaeozoicEarly
Mesozoic sharks were stenohaline (eugeneodonts),
euryhaline (some hybodonts) or occured predomi-
nantly in freshwaters (xenacanths) and are hence
excellent indicators for palaeoenvironments.
But should we continue to observe a rising
number of ‘Lazarus taxa’ in ever earlier stages in
the Early Triassic, we may be forced to think about
alternative explanations for the ‘reappearance’ of
taxa and will have to attempt a quantification of
the Early Triassic sedimentation rates and their
bearing on the rock and fossil gap. Recent research
confirmed that the Induan represents an extremely
short timeframe (see Ogg 2004) during which a
smaller volume of sedimentary rock, and hence
fossil preservation, may be expected.
The pre-break-up phase of Pangaea, the Triassic,
is particularly interesting because it spans a time-
frame that holds a key to understanding Mesozoic
and even extant biotic diversity. From today’s
perspective it seems improbable that global
environmental changes on the scale of the Permo-
Triassic boundary event or the Jurassic Pangaea
break-up event have been paralleled by an event
comparable in significance during the Triassic.
Turnovers in faunal composition also occurred
during the Triassic, and the causes for these alleg-
edly minor changes may no longer be negligible
for reconstruction of the Triassic recovery scenario.
Establishing a temporal sequence of small-scale
(non-global) environmental changes is a necessity
in identifying more localized ‘turning points’ in
Pangaean history that clearly pre- or clearly post-
date the Permo-Triassic boundary. Only this data
will provide a more detailed scenario of Late
Palaeozoic/Early Mesozoic palaeobiogeography
and disappearance of certain groups of vertebrates.
It may be concluded that although environ-
mental and faunal changes occurred during the
Triassic at a smaller scale, these events may not
necessarily have had a less severe effect on the
faunal turnover.
The importance of including detailed alpha-
taxonomical studies of Lower Triassic fish
remains when interpreting the scenario of the
Permo-Triassic faunal turnover can hardly be over-
estimated because the assessment of changing
diversity is always based on taxonomy and not on
the fossil record itself. It is likely that poorly-
preserved fish groups such as eugeneodontids tend
to be overlooked due to the lack of an established
taxonomical framework. From this perspective,
the eugeneodontids are an extraordinary example,
because not only has their stratigraphical
distribution been underestimated, but also their
diversity and geographical occurrence apparently
mainly due to the lack of appropriate preservation
(poor calcification and fragmentary condition).
Eugeneodontids are most probably strictly marine
and highly specialized fishes that are now known
to co-occur in astonishing diversity across the
Permo-Triassic boundary in the eastern Panthalassa
and in the Proto-Atlantic. The single find in the
eastern Palaeo-Tethys (cf. Helicampodus? From
Dingri, Xian County) further expands the eugeneo-
dontids’ strato-palaeogeographic distribution.
Future investigation of the undescribed eugeneo-
dontid material from the Permo-Triassic of East
Greenland may significantly amend our comprehen-
sion of palaeobiology of these sharks. It is also
possible that Permo-Triassic eugeneodontid oral
teeth remain unidentified in various collections
because their dental remains were previously not
expected to occur in the Smithian and because
their minute distal and some of their lateral
teeth are not easily distinguished from other,
non-eugeneodontid shark teeth.
Apart from the serious difficulties in accurate
dating of classical Late Permian and Early Triassic
fish sites, as discussed above, there are a number of
other uncertainties linked to that particular fossil
record in general (e.g. hiatuses, reworking and
sampling) and to taxonomy and phylogeny of
organisms across the Permo-Triassic biotic bound-
ary transition. These problems are reminiscent
of those encountered when interpreting the
CretaceousTertiary biotic transition (see
MacLeod et al. 1997).
In the case of relatively high faunal diversity in a
geographically remote area and in stratigraphically
close proximity to the boundary, a peak in diversity
would be interpreted as a biotic refugium following
the extinction event (see e.g. Cope et al. 2005). This
scenario would be likely to change with a more
complete record at hand and does not explain the
occurrence of archaic, taxonomically diverse
sharks in an open marine habitat during the early
Olenekian.
Abbreviations used in text and text-figures
art, articulating area of lower jaw; ba(s), branchial
arch(es); bc, basal cartilage; bs, base or root (of
tooth or denticle); cart, unidentifiable cartilaginous
element(s); cer, ceratotrichia; cirdep, circular
depressions; cr, crown (of tooth or denticle);
dcrest, dorsal crest; dent, dentition; el, enameloid
layer; he, haemapophysial elements; mt, mesial
tooth family; nc, neurocranium; ne, neurapophysial
elements; ns, nasal septum; ldep, lateral depression;
lj, lower jaw; ne, elements; occr, occipital rim of
neurocranium; od, orthodentine; orb, orbit; os,
TRIASSIC EUGENEODONTID SHARKS 37
osteodentine; pbas, basal element of pectoral girdle;
pf, pectoral fin; pg, pectoral girdle; porb, postorbital
process (of the neuocranium); prorb, preorbital
process; rb, rostral bar; rcav; superficial rostro-nasal
cavities; scac, scapulocoracoid; scl, sclerotic ring;
sdd, shagreen of dermal denticles; slep, single lepi-
domorial denticles; sorb, supraorbital process (of
the neurocranium); spiden, denticles with elongate
central cusp (on the neurocranium); ste, sternal
element; sym; symphysial area of lower jaws;
symt, symphysial tooth of the lower jaw; tpc,
tubular pulp cavity; uj, upper jaw; vd, vitrodentine;
visc, visceral elements.
We acknowledge review and critical comments by
C. Underwood, M. Richter and A. Longbottom. Numerous
colleagues helped with collection of specimens and with
field and lab assistance: M. Johns (Pacific PaleoQuest,
Brentwood Bay), L. Pyle (EOSUV), B. Chatterton,
S. Gibb and R. McKellar (UAEAS), J. Bruner,
T. Bullard, A. Lindoe, M. V. H. Wilson (UALVP),
many staff and volunteers of the RTMP, P. McClafferty
and Y. Mutter. Thin sections were made by D. Resultay
(UAEAS). Financial support was received with research
and travel grants from following foundations: SNF
(81ZH-68466 and PA002-109021), J. de Giacomi (Swiss
Academy of Sciences, travel grant), R. L. Thyll-Du
¨rr,
Arlesheim (research grant), Theodore Roosevelt Fund,
New York, USA (research grant), Zu
¨rcher Universita
¨ts-
verein (FAN grant: all to RJM) and NSERC grant (to
Mark VH Wilson, UALVP). Transport of fossils was
kindly arranged and partly sponsored by Veritas Energy
Services Ltd. (Ed Schreuder, Calgary), and TMP sup-
ported part of the field trips and CT studies. The final
stage of this research was supported by a Marie Curie
Intra-European Fellowships within the 6
th
European Com-
munity Framework Programme (MEIF-CT-2006-023691).
Appendix 1
Additional material studied
This list contains important specimens housed at AMNH
and BMNH used for comparison
Agassizodus variabilis (Newberry & Worthen, 1870):
AMNH 6662 from upper Pennsylvanian, Holt Shale -
Virgil Series, quarry Kaser Bros & Bartlett, Iowa
(section of jaw). AMNH 6663 from the Pennsylvanian
of Wea Shales, quarry Papillion, Nebraska, USA (dis-
articulated jaws with scattered teeth, shoulder girdle
element). AMNH 6664 from the middle Pennsylva-
nian, Greenfield, (quarry) Stark-Shale Missourian,
Iowa, USA (shagreen of denticles).
Agassizodus sp.: AMNH 19623 from the ?Carboniferous
Oolagh Formation, locality Dewey Cement, Tolsa,
Oklahoma, USA (Gilmore collection, ‘Itano nr. 5’) (a
tooth fragment). Also: unlabelled specimen, in the
Cope Collection AMNH from the Lower Permian
Red Beds, Texas, USA (7 teeth).
Campodus agassizianus de Koninck, 1844: BMNH
P. 28754 (part of type) from the Lower Carboniferous
of Chockier near Lie
`ge, Belgium (disarticulated distal
teeth in concretion).
Campodus rectangulus Trautschold, 1879: BMNH
P. 7053/4 from the ?Middle/Upper Carboniferous of
Myachkovo, Moscow, Russia (4 fragmentary teeth).
Campodus variabilis Newberry & Worthen, 1870: BMNH
P. 9673/4 from the Upper Carboniferous Coal
Measures in Cedar Creek, Nebraska, USA (casts of
?symphysial and other tooth files).
?Campodus sp.: AMNH 7084 from Upper Coal Measures,
Cedar Creek, Nebraska, USA (cast of partial
symphysial tooth whorl). AMNH 8853 from
U. Pennsylvanian, near Topeka, Kansas, USA – same
species comes also from Osaga County, Kansas (denti-
tion of left lower jaw in place). Unlabelled specimen
AMNH from Black Hills, Powder River, South
Dakota, USA (broken lateral tooth file with 4 teeth).
Campodus sp.: BMNH P. 12931 from the Lower Carbon-
iferous (Pendleside Beds) of High Greenwood,
Hardcastle Croggs Valley in Sowerby, West Riding,
Yorks, UK (isolated mesial and lateral teeth embedded
in various views).
Campyloprion ivanovi (Karpinsky, 1922): BMNH P.
37767/8 from the Upper Carboniferous (C
3
, Ghzhel
stage) of Rusavkino (near Moscow), Russia (casts of
partial tooth whorls). See also Eastman (1902).
Edestus giganteus Newberry, 1888: AMNH 225 (holo-
type) from the Pennsylvanian (Coal Measures) of
Illinois, USA (symphysial teeth).
Edestus heinrichi Newberry & Worthen, 1870: AMNH
488 (cast of holotype)from Pennsylvanian, Coal
Measures, Belleville, Illinois (symphysial teeth).
BMNH P. 2231/2, 3151, 4795 and unlabelled BMNH
specimens from the Upper Carboniferous of Coal
Measures, Belville, Illinois, USA (casts of lower sym-
physial tooth whorls and isolate fragmentary teeth).
Edestus karpinskii Missuna, 1908: BMNH P. 37770 from
the Upper Carboniferous (C
2
; Myachkovian) near
Kolomna, Moscow District, Russia (cast of holotype,
a fragmentary symphysial tooth whorl).
Edestus newtoni Woodward, 1917 [Lestrodus Obruchev,
1953]: BMNH P. 12362 from the ?Upper Carbonifer-
ous of the Millstone Grit, Brockholes, Yorks, UK
(3 tooth fragments in situ).
Edestus protospirata (Trautschold, 1888): BMNH
P. 37769 from the Upper Carboniferous (C
2
; Myatch-
kovo horizon) of Akishino, River Oka, Ryazansk
District, Russia (cast of symphysial tooth whorl). See
also Obruchev (1951).
Edestus sp.: BMNH P. 16195 from the Lower Devonian
near Bundenbach, Hunsru
¨ck Shale, Rhenish Prussia,
Germany (almost complete, obliquely flattened tooth
whorl).
Fadenia gigas Eaton, 1962: AMNH 8780 (cast of holo-
type) from Lower Pennsylvanian, U. Cherokee Shale
(Lexington Coal), Lucas, Henry County, Missouri,
USA (2 casts of symphysial teeth).
R. J. MUTTER & A. G. NEUMAN38
Helicoprion bessonowi Karpinsky, 1899: AMNH 7212
from the Permo-Carboniferous of Artinsk Fm,
Krasnoufimsk, Ural, Russia (cast of holotype of sym-
physial tooth whorl; AMNH 7213 is another cotype).
BMNH P. 9693/4, 15640-3 from the Lower Permian
(Ph
A Artinskian-Divia Beds), quarry near Krasnou-
fimsk, Stonspits, west of Divia-Gora, Russia (quarter
of tooth whorl and casts of tooth whorls).
Helicoprion davisi Woodward, 1886: BMNH P. 5122
from the Lower Permian of Gascoyne District, West
Australia (cast of holotype partial tooth whorl).
Helicoprion ferrieri Hay, 1907 (in Hay [1909]) (Lisso-
prion ferrieri Hay, 1907): AMNH 7549 (cotype) from
the Permo-Carboniferous, near Montpellier, Bear
Lake, Idaho, USA (fragment of symphysial tooth file,
for name see Romer [1960]). BMNH P. 47782/3
from the Middle Permian Phosphoria Fm of Waterloo
Mine, Montpelier Canyon, SE Idaho, USA (casts of
symphysial tooth whorls)
Ornithoprion hertwigi Zangerl, 1966: unlabelled remains
AMNH from Bradfield quarry (small quarry prepared
for the 9
th
International Carboniferous Congress, May
1979, at Urbana, Illinois; location: along Highway
41; 1
8mile up the highway from discovery site of
Mecca Quarry Shale, just south of Section line 29,
T15 N, R8W; Wabash Township; Parke County,
Indiana, USA), Mecca Quarry Shales, Kansas, USA,
and found in 1979 (lower jaw, tail and unidentified
remains). BMNH P. 62284/5 and unlabelled specimens
BMNH from the Upper Carboniferous (Westphalian D)
of the Carbondale Fm, Bethel Quarry, Pike County,
Indiana, USA (various skeletal remains, unprepared).
Ornithoprion nevadensis Wheeler, 1938: BMNH P. 22976
from the Lower Permian of Koipato Fm, University of
Nevada locality 28, Rochester District, Lovelock
quadrangle, Pershing County, Nevada, USA (cast of
symphysial tooth whorl).
Orodus variabilis’ Newberry, 1875: AMNH 11545
(cotype) from the ?Carboniferous of Waverly Group,
Vanceburg County, USA (1 tooth, 1 tooth fragment) and
numerous BMNH teeth, not referred to in the paper.
Unidentified eugeneodontids (?Caseodus): unlabelled
specimens AMNH from Ace Hill quarry, Upper
Permian, Queen-Hill Shale-Virgilian (scattered teeth
and imprints with partial jaws) and (also AMNH) from
Mecca Quarry Shales (Liverpool cyclothem; Linton
Formation; Des Moines Series), Westphalian Upper C
(or Lower D), Pennsylvanian localities, Indiana, USA
(neurocranium and posterior visceral elements?).
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TRIASSIC EUGENEODONTID SHARKS 41
... The species ' Polyacrodus ' contrarius Johns , Barnes & Orchard , 1997 was grouped with ' P . ' bucheri Cuny , Rieppel & Sander , 2001 and provisionally placed in the family Homalodontidae by Mutter et al . ( 2007 , 2008 ...
... on into ' Polyacrodus ' bucheri of some teeth described as Acrodus sp . from the Middle Triassic of Saudi Arabia by Vickers - Rich et al . ( 1999 ) . Saudi Arabia was close palaeogeo - graphically to Oman , thus strengthening the suggested relationship between the discussed taxa . The provisional inclusion of the two species in Homalo - dontidae ( Mutter et al . 2007 , 2008 ) , the taxonomic posi - tion of which is still unclear ( Mutter et al . 2007 ) , was more definitively followed by Pla et al . ( 2013 ) . However , we doubt that Omanoselache belongs to Homalodontidae : the characteristic blunt posterior teeth are also present in the Homalodontidae ( Mutter et al . 2007 ) but the monocus - pid mesial t ...
... 2001 , 2007 ; Dorka 2003 ; Bender & Hancox 2004 ; B»a_ zejowski 2004 ; Yamagishi 2004 , 2006 , 2009 ; Mutter et al . 2007 ; Romano & Brinkmann 2010 ) as well as eugeneodontiform taxa ( Nielsen 1952 ; Obruchev 1965 ; Zhang 1976 ; Mutter & Neuman 2008 ) . The only published records of Early Triassic neoselachian dental remains to date are of a ? ...
Article
Elasmobranchs are reported for the first time from Lower Triassic deposits in Oman. The well-preserved remains consist of isolated teeth, dermal denticles and fin spines, recovered from conodont residues. The low-palaeolatitude sections consist of Lopingian–Olenekian shallow and pelagic carbonates in exotics, olistoliths and breccia blocks that have been redeposited in younger allochthonous strata of the Hawasina Basin throughout the Oman Mountains at Jabal Safra (olistoliths within the Jurassic Guwayza Formation, Olenekian), as well as at Wadi Alwa (exotic Alwa Formation, Lopingian–Olenekian) and Wadi Wasit Block (slope breccia in the Al Jil Formation, Induan), both of which occur in the Ba’id region. The recovered fauna contains a small number of pre-existing genera, but is mainly composed of new hybodont and neoselachian taxa. They are identified as: Omanoselache halli Koot & Cuny sp. nov., cf. Omanoselache sp., Safrodus tozeri Koot & Cuny gen. et sp. nov. and Polyfaciodus pandus Koot & Cuny gen. et sp. nov., based on the majority of the recovered dental remains. Spine fragments are identified as cf. Amelacanthus sp. This fauna represents the second published record of neoselachian teeth from the Induan and the most extensive record from the Lower Triassic in terms of abundance and diversity. The fauna is dominated by Neoselachii, whereas other Early Triassic faunas are hybodont-dominated, and histological study of the neoselachian enameloid significantly adds to our knowledge of the early stages of their evolution. All described taxa are new to the Oman fossil record and that of western Neotethys, apart from Omanoselache and Amelacanthus, which have been recognized from Wordian deposits, and Omanoselache is the second genus from Oman known to have survived the late Permian mass extinction. The level of faunal diversity recognized here is comparable to other Early Triassic faunas but is much reduced compared to the Wordian pre-extinctions fauna.
... There is no doubt that top predators must have persisted in some refugia, otherwise they would have disappeared during the EPME. Predatory groups have been reported from younger strata of the Early Triassic, for instance, eugeneodontid sharks from the Griesbachian substage (Mutter and Neuman, 2008), hybodont sharks from the early Spathian of the Olenekian Stage (Wang et al., 2001), perleidid fishes from the Dienierian substage of the Induan (Beltan, 1996), and actinopterygians such as Birgeria and Saurichthys from the Griesbachian substage (Stensiö, 1932;Kogan, 2011). Other large predators such as diverse marine reptiles in the Olenekian, belong to entirely new clades; therefore, they are not exactly survivors through the crisis (Benton et al., 2013). ...
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The end-Permian mass extinction led to the disappearance of >81% of marine species and the collapse of marine ecosystems. Despite the progress made in recent years, the severity of the impact of the mass extinction upon some groups still remains unclear. Horseshoe crabs are a typical example among these groups. Here we report a new fossil horseshoe crab, Guangyuanolimulus shangsiensis gen. et sp. nov. from the Permian-Triassic transitional beds in South China, representing the earliest putative fossil record of Limulidae. The occurrence of horseshoe crabs during the Permian-Triassic transition indicates the existence of a trophic web containing at least three levels immediately after the main pulse of the end-Permian mass extinction. Horseshoe crabs might have played an important role as predators in marine communities during the Permian-Triassic transition and the earliest stage of recovery.
... Lower Triassic marine successions yield a few fish faunas worldwide, including South China, India, Madagascar, Spitsbergen, Greenland, and Western Canada (Beltan, 1996 Jin, 2006;Tong et al., 2006;Weitschat, 2008;Mutter and Neuman, 2008b;Romano and Brinkmann, 2010;Falconnet and Andriamihajia, 2012;Romano et al., 2012;Scheyer et al., 2014;Romano et al., 2016aRomano et al., , 2016b, and their detailed faunal compositions are listed in Table 1 (Liu et al., 2002). Perleidus piveteaui, re-assigned to Plesioperleidus jiangsuensis (Jin et al., 2003;Tong et al., 2006), was also identified by Liu et al. (2002) from Jurong. ...
... Records of Late Permian xenacanthiforms and jalodontids are unknown. But, some Palaeozoic groups such as xenacanthiform (genus Mooreodontus), ctenacanthiforms (genera Carinacanthus and Pyknotylacanthus), eugeneodontiforms (genera Caseodus, Paredestus, Fadenia, Helicampodus, Parahelicampodus) and probably jalodontids survived to the Triassic (Nielsen, 1952;Obruchev, 1965;Maisey, 1975;Mutter and Rieber, 2005;Mutter and Neuman, 2008;Ginter et al., 2010;Ivanov, 2013b). The hybodonts were a group of sharks that persisted to the end of the Cretaceous. ...
Article
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... The latter condition is shared with the platysiagiforms, and possibly shared with certain acrolepiforms (see Aldinger, 1937). Recent research on chondrichthyans has yielded evidence that the end-Permian extinction event may have been rather 'selective', possibly enhancing survival or extinction, in relation to certain biological specialisations leading to ecological adaptations (Mutter and Neuman, 2006, 2008a, 2008b, 2009. At present, it is unclear what specific cause and effect scenarios took place at the two 'extinction boundaries', and it is evident that only more detailed fieldwork at suitable boundary sections and investigations into latest Palaeozoic and early Mesozoic fish groups will enable us to track putative phylogenetic lineages and palaeobiogeographic patterns across both boundaries in order to better tackle extinction/recovery scenarios. ...
Chapter
The early Mesozoic has recently received much attention with respect to the recovery of marine life from the greatest ever (end-Permian) extinction event and another major extinction event at the end of the Triassic (overviews in Erwin, 2006; Smith, 2007; and references therein). The Permian/Triassic Boundary (PTB) in particular may play a pivotal role in assessing putative cause-and-effect scenarios during the Palaeozoic-Mesozoic transition (Algeo et al., 2007). However, ‘sh species-normally making up at least 50% of the fossil record of vertebrates and a key to understanding the Palaeozoic-Mesozoic faunal turnover-are remarkably rare in PTB localities, yet quite abundant in a number of classical localities of Late Permian and early Mesozoic age. Due to the scarcity or even absence of ‘sh remains in known PTB sections and rocks immediately on either side of the PTB, these Permian-Triassic localities have recently attracted considerable scienti’c attention. At the family level (Pitrat, 1973; Schaeffer, 1973; Benton, 1993), the composition of the respective ichthyofaunas seems to be fundamentally different. And indeed, numerous Triassic ‘sh genera cannot be traced back to Palaeozoic ancestors, whereas ichthyofauna diversity increased during the early Middle Triassic (Mutter, 2003).
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Sauropterygia, one of the main clades of Mesozoic marine reptiles, diversified shortly after the Permo-Triassic biotic crisis and afterwards remained one of the major components of Early Triassic and later Mesozoic marine ecosystems. On the other hand, actual specimens of marine reptiles of Olenekian age are still rare in the fossil record, coming only from a few localities worldwide. Here we describe associated remains of a larger marine reptile of around 4 m body length, with nothosauroidean affinities from the Sulphur Mountain Formation exposed at the L cirque locality of Wapiti Lake area in British Columbia. Although the specimen records only scattered parts of the posterior vertebral column, some gastral ribs and most notably, the proximal portion of one hind limb together with a fan-shaped ischium, it represents one of the oldest records of Sauropterygia and larger representatives of aff. Nothosauroidea specifically, as well as the northernmost occurrence of such animals in the Triassic. As such, the new specimen is important for understanding the biogeography and early evolution of the group and that of Sauropterygia, in general. Key words: Reptilia, Eosauropterygia, paleobiogeography, biotic recovery, apex predator, Olenekian, British Columbia, Ganoid Ridge.
Article
A new, diverse and complex Early Triassic assemblage was recently discovered west of the town of Paris, Idaho (Bear Lake County), USA. This assemblage has been coined the Paris Biota. Dated earliest Spathian (Olenekian), the Paris Biota provides further evidence that the biotic recovery from the end-Permian mass extinction was well underway ca. 1.5 million years after the event. This assemblage includes mainly invertebrates, but also vertebrate remains such as ichthyoliths (isolated skeletal remains of fishes). Here we describe first fossils of Chondrichthyes (cartilaginous fishes) from the Paris Biota. The material is composed of isolated teeth (mostly grinding teeth) preserved on two slabs and representing two distinct taxa. Due to incomplete preservation and morphological differences to known taxa, the chondrichthyans from the Paris Biota are provisionally kept in open nomenclature, as Hybodontiformes gen. et sp. indet. A and Hybodontiformes gen. et sp. indet. B, respectively. The present study adds a new occurrence to the chondrichthyan fossil record of the marine Early Triassic western USA Basin, from where other isolated teeth (Omanoselache, other Hybodontiformes) as well as fin spines of Nemacanthus (Neoselachii) and Pyknotylacanthus (Ctenachanthoidea) and denticles have been described previously.
Article
A new, diverse and complex Early Triassic assemblage was recently discovered west of the town of Paris, Idaho (Bear Lake County), USA. This assemblage has been coined the Paris Biota. Dated earliest Spathian (Olenekian), the Paris Biota provides further evidence that the biotic recovery from the end-Permian mass extinction was well underway ca. 1.5 million years after the event. This assemblage includes mainly invertebrates, but also vertebrate remains such as ichthyoliths (isolated skeletal remains of fishes). Here we describe first fossils of Chondrichthyes (cartilaginous fishes) from the Paris Biota. The material is composed of isolated teeth (mostly grinding teeth) preserved on two slabs and representing two distinct taxa. Due to incomplete preservation and morphological differences to known taxa, the chondrichthyans from the Paris Biota are provisionally kept in open nomenclature, as Hybodontiformes gen. et sp. indet. A and Hybodontiformes gen. et sp. indet. B, respectively. The present study adds a new occurrence to the chondrichthyan fossil record of the marine Early Triassic western USA Basin, from where other isolated teeth (Omanoselache, other Hybodontiformes) as well as fin spines of Nemacanthus (Neoselachii) and Pyknotylacanthus (Ctenachanthoidea) and denticles have been described previously.
Article
Full-text available
Present paper gives an updated summary of research history on the Chon-drichthyes and Osteichthyes of the Early Triassic (Griesbachian, Dienerian, Smithian, Spathian) and primarily of the early Anisian. Early Triassic and Anisian marine and freshwater ichthyofaunas are found on all continents except South America, and much more fish assemblages are known from the Northern than from the Southern Hemisphere. The Early Triassic and the Anisian are times of major importance for the phylogeny of the Chondrichthyes and Osteichthyes. After the end-Permian mass extinction the surviving groups of the cartilaginous and bony fishes recovered, and many new forms appeared in the Early Triassic. The neosela-chians as well as close relatives of the teleosteans evolved, clades to which nearly all extant fishes belong. Present publication also provides a revised data base for the distribution of Early Triassic and early Anisian chondrichthyan and osteichthyan fishes in time and space on which future research on their paleo biodiversity shall be guided.
Chapter
Five new chondrichthyans from the Pennsylvanian Mazon Creek fauna are described. Two are elasmobranchs, belonging to the order Ctenacanthoidei. The remainder belong to that varied group of cartilaginous fishes that are clearly not elasmobranchs, and for which the traditional group name Holocephali is no longer applicable. For this group, the sister group of the Elasmo-branchii, the name Subterbranchialia is proposed. Of the three forms in the Mazon Creek fauna that belong to this group, one is interpreted as a chimaeroid, one a very juvenile individual of a bradyodont species, and one, Polysentor gorbairdi, does not have any close relatives among the presently known Subterbranchialia. Of the ctenacanthoid sharks, one is another species of the genus Bandringa, also of this fauna, the other is a species with morphological features that clearly indicate an evolutionary trend within this group toward the hybodont level of organization.