Table Of Content© Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at
Nautiloid cephalopods – a review of their use and
potential in biostratigraphy
D.H. EVANS, A.H. KING, K. HISTON & M. CICHOWOLSKI
Abstract: In terms of their use as biostratigraphical tools, nautiloid cephalopods are the poor relations of ammonoids. Neverthe-
less, in certain situations, they may provide useful biostratigraphical data, particularly where other biostratigraphically valuable
taxa are not present; or in certain situations demonstrate a resolution as great as, or greater than ammonoids, trilobites, grapto-
lites or conodonts. Nautiloid cephalopods are of especial value in palaeobiogeographical studies, but their use for this purpose may
be hampered by the poor understanding of the stratigraphical ranges of individual taxa. The biostratigraphical value of nautiloid
cephalopods is demonstrated here through a number of case studies of Ordovician taxa, combined with a review of their biostrati-
graphical use in Palaeozoic and Mesozoic successions. These both demonstrate the potential of this group and indicate great scope
for further research.
Keywords: Nautiloids, cephalopods, biostratigraphy, Palaeozoic, Mesozoic
Introduction taxonomically without investigation of the internal
morphology of the phragmocone due to the similarities
The widespread stratigraphical and geographical
of the external features, thus entailing the preparation
occurrence of nautiloid cephalopods, particularly, but
of polished or thin sections for study, requiring more ef-
not exclusively during the Lower Palaeozoic is docu-
fort, and possibly resulting in more equivocal data than
mented in many substantial monographic works (e.g.
might be gained from the preparation of (for example)
HALL1847 [Ordovician and Silurian]; BARRANDE1865-
a conodont sample.
1877 [Ordovician to Devonian]; BLAKE 1882 [Ordovi-
cian and Silurian]; FOORD 1897-1903 [Carboniferous]; 3. Taphonomy: Amongst the many forms with or-
FOERSTE 1932, 1933 [Ordovician]; FLOWER 1946 [Or- thoconic shells, there is great potential for post-mortem
dovician]; KUMMEL 1953 [Triassic]; MILLER & – pre-burial breakage and preferential removal of parts
YOUNGQUIST 1949 [Permian]; STURGEON et al. 1997 of the phragmocone to bring about the selective preser-
[Carboniferous]; ZHURAVLEVA 1974 [Devonian]). Un- vation of parts of the shell on which the diagnosis of a
like ammonoids, which have been utilised as strati- particular taxon may be based. Taphonomic studies of
graphical tools since the early nineteenth century (e.g. the post-mortem behaviour and deposition of nautiloid
SMITH 1816; OPPEL 1865; BUCKMAN 1898; HOUSE cephalopod shells (REYMENT 1958; BOSTON & MAPES
1978; CALLOMANet al. 1989; KORN1996; KLUG2002; 1991; HEWITT & WESTERMANN 1996; HISTON 2012a)
BECKER2000; PAGE2009), and despite the great varia- deal with many aspects of their preservation. If there is
tion in conch morphology that ‘nautiloids’ display, ex- more than one mode of preservation for a particular
amples of their use in the development of biostrati- taxon, and particularly if these occur at different hori-
graphical schemes are relatively scarce. There are sev- zons, there is potential for mistakenly splitting that tax-
eral possible reasons for this: on and failing to recognise its full stratigraphical range.
For example, Polymeres demeterum MURCHISON from
1. Biostratigraphical markers: There are a range of
the Floian of England and Wales occurs at several dif-
other rapidly evolving and widely occuring taxa such as
ferent horizons where the preserved remnants of conch
graptolites, ammonoids, conodonts and foraminifera
represent either adoral, medial or apical portions,
that are of proven value, and may occur in great abun-
whilst their preservation may take the form of internal
dance, facilitating correlations using samples extracted
and external moulds, lacking original shell, or original Denisia 32,
from cores. zugleich Kataloge des
shell may have been replaced by pyrite followed by fur-
oberösterreichischen
2. Similarity of morphology: Many of the groups ther replacement with limonite. Without careful study Landesmuseums
Neue Serie 157(2014):
comprising these cephalopods cannot be determined of this material and an understanding of its taphonomy,
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it would be easy to determine these as separate taxa and relatively rare, as in the Durness Group of Northwest
set up spurious ranges for them. Scotland (EVANS2011) should not be underestimated.
4. Fidelity of palaeogeographical distribution: An The study of the distribution of nautiloid
important factor in this discussion is whether the nau- cephalopods for palaeobiogeography and as tools for
tiloid shell could float after death of the animal as then palaeogeographical reconstruction was strongly pro-
the original palaeoenvironmental setting and any hy- posed by CRICK in the 1980’s and 1990’s (CRICK 1980,
pothesis related to facies and assemblages would be 1988, 1990, 1993). He put forward valid arguments sup-
prone to error. This has led to the use of nautiloids as re- ported by a sound database of systematic works to sup-
liable biostratigraphic markers and precise indicators of port his hypotheses that these faunas are particularly
palaeoenvironment being treated with doubt or com- sensitive to distance or water depth separating land-
pletely dismissed in holostratigraphical studies. HEWITT masses and to fluctuations in sea level. As CRICKpoint-
& WESTERMANN (1996) concluded that post-mortem ed out faunas should be described using precise system-
buoyancy of nautiloid shells was limited as most individ- atic criteria within a strictly controlled biostratigraphic
uals lived on or near the seafloor and would sink soon
framework in order to fully exploit their potential.
after death rather than float to the surface as the camer-
When CRICKpublished his major contributions this was
al chambers flooded. Therefore, it is considered that
not always the case and many systematic studies were
nautiloid shells were deposited on the seafloor shortly
lacking a precise stratigraphic context even at series lev-
after the death of the organism and would have re-
el, many taxa being referred to as “Upper Ordovician”,
mained buoyant for only a short period, if at all
“lower Silurian” etc. These seminal works by CRICK
(KRÖGERet al. 2009; KLUGet al. 2010; HISTON2012b). gave impetus to a broad array of studies over the last
As a probable consequence, examples of the direct twenty years by other authors (e.g. CICHOWOLSKI,
application of nautiloid cephalopods as biostratigraphi- EVANS, FREY, HERWIG& POSENATO, HISTON, HOLLAND,
cal tools are relatively few. However, this is principally KING, KLUG, KRÖGER, MAPES, and NIKOamong others:
due to the fact that nautiloid biostratigraphical zones/ see reference list for details) on these faunas from a va-
schemes have never been attempted, not as a result of riety of geographic locations ranging stratigraphically
failure in their application. More often, biostratigraphi- from the Ordovican to the Triassic that have shown
cal studies of these cephalopods are markedly descrip- without doubt that nautiloid cephalopods are indeed re-
tive, and may largely represent an extension of a mono- liable palaeobiogeographical indicators. Nautiloid stud-
graphic study (e.g. FREY 1995; STURGEON et al. 1997; ies are now much more accurate in this respect when
KRÖGER2008a; EVANS2005, 2011), or the provision of based on newly collected material, however, material
known ranges for a particular region/locale (e.g. WIL- being redescribed from historical collections is still a
SON 1961; CATALANI in SLOANE 1987). Rousseau major problem and as CRICKsuggested, is often only of
FLOWERwas probably one of the main exponents of the use from a taxonomic point of view.
use of these cephalopods as biostratigraphical tools, and
More recent studies of nautiloid cephalopods may
used his knowledge of their distribution, particularly in
recognise the difficulties that can arise when attempting
North America, to review the biostratigraphy of various
to use these organisms as biostratigraphical tools and
successions of Lower, Middle and Upper Ordovician age
make use of new collections sampled within a well-con-
and also as a tool to better understand the evolution of
strained biostratigraphical frame-work. Studies of the
this group of cephalopods (see FLOWER 1976; 1985 for
Silurian cephalopods from Europe in particular (e.g.
summaries). In one instance, FLOWER (1964) used his
knowledge of the stratigraphical distribution of Canadi- HISTON2012a; HISTONet al. 2010; MANDAet al. 2009)
make use of such a well-constrained biostratigraphical
an (= Lower Ordovician) cephalopods of North Ameri-
ca to date some of the larger clasts present in the Levis frame work to accurately constrain the range of taxa oc-
Conglomerate of Quebec, demonstrating that the boul- curring within the succession, and contributes, in com-
ders originated from carbonates ranging (in modern ter- bination with previous studies of other European faunas
minology) from Skullrockian to Blackhillsian in age, (see sections below for references) to their use in bios-
and indicating a source or sources further shoreward on tratigraphical correlation as well as a palaeobiogeo-
the Laurentian platform. In this case the general lack of graphical tool within the framework of Northern Gond-
other macrofossils made these cephalopods a key to the wana. Such an approach, which recognises that the
age determination of this material, and although today, stratigraphical distribution of these cephalopods should
age would probably be determined by conodont sam- be assessed within a background of other biostratigraph-
pling, the value of these cephalopods in assisting age de- ical constraints are more likely to yield useful results in
termination in situations where other macrofossils are terms of developing their biostratigraphical value.
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Examples from recent studies the Tremadoc-Floian boundary based on the strati-
graphical and palaeogeographical distribution of pelagic
There are a number of situations where the real or
trilobites (ADRAIN 2011) indicates that the delay be-
potential biostratigraphical value of these cephalopods
tween the appearance of the Orthoceratoidea in high
may be of significance. Where other biostratigraphical-
latitude sites on the west Gondwana margin and at low
ly critical fossil biota may be relatively rare, as is the sit-
latitudes (NW Scotland, Newfoundland, SW United
uation along parts of the Laurentian margin during the
States) is significantly less than previously thought.
Early Ordovician (above), areas of the North Gond-
Such a rapid dispersion (if that is what we are observ-
wana margin where Silurian cephalopod limestones
ing) of this group of cephalopods would appear to be in
dominate, or in parts of the Early Jurassic successions of
accord with a move to a more pelagic habitat (KRÖGER
the North Somerset coast (United Kingdom) described
et al. 2009) and would suggest that the adaptations not-
further below. Where these cephalopods are particular-
ed by KRÖGER (2005); particularly the appearance of a
ly abundant, as in parts of the Ordovician successions of
small subspherical protoconch that may have facilitated
Scandinavia and South China, some groups, such as the
the rapid dispersal of large numbers of offspring, took
lituitids (see below), underwent a rapid evolution, and
place very early in the history of the group and is likely
may be distinguished as a sequence of distinct taxa that
to be present in all the taxa referred to in Fig. 1, despite
in some cases can be recognised on both palaeoplates,
the lack of any evidence of this morphology in most of
and may potentially be used as correlative tools. Studies
these taxa as a consequence of the rarity of preservation
by MANDA(2009) of the phragmocerids from the classic of the apical portion of the phragmocone.
Silurian deposits of the Prague Basin also demonstrate
this aspect. Use of Silurian nautiloid assemblages by At present, with the exception of Slemmestadoceras
GNOLI(1990) and MANDA& KRIZ(2006) highlight the attavus(BROEGGER), the earliest known members of the
potential for correlation. Significant, and/or relatively Orthoceratoidea are represented by taxa possessing mar-
rapid evolutionary events during the history of these ginal siphuncles. These may be assigned to Bactroceras
cephalopods may also have some degree of biostrati- HOLM, or closely related genera, all of which so far have
graphical value, and examples from the early history of shown no evidence of the presence of cameral deposits,
the Orthoceratoidea and the Eothinoceratidae are de- and only Thoraloceras bactroceratoidesKRÖGER& EVANS
possesses endosiphuncular deposits that may be inter-
scribed here. Finally, where the stratigraphical distribu-
preted as a conical lining that is thicker at the septal
tion of cephalopods are well constrained, whilst they
necks than along the rest of the siphonal segment. Giv-
may not provide the primary evidence on which to
en that this taxon is known only from very fragmentary
found a biostratigraphical scheme, may provide a signif-
material and it is not known whether cameral deposits
icant contribution to more comprehensive, holostrati-
might have been present, some doubt will remain re-
graphical schemes.
garding its assignment to the Troedsonellidae (Dissido-
The examples provided below have a strong Ordovi-
cerida).
cian and lower Palaeozoic bias, reflecting the research
Uncertainty regarding an appropriate assignment
interests of the authors. As such, they provide an indi-
for Thoraloceras, together with the presence of Bactro-
cation of the potential for the use of nautiloid
cerasin the same assemblage, combined with a possible
cephalopods as biostratigraphical tools, and indicate,
Cochliocerasthat is marginally younger means that it is
together with the Mesozoic examples that these
not possible to resolve the relationships between these
cephalopods can be used in a biostratigraphical context.
taxa without additional data. A cladistic analysis
Ordovician (KRÖGER 2008b) generated over one hundred similarly
parsimonious trees, although it should be noted that
1. Orthoceratoidea. Research carried out during the
characters including the presence/absence and nature of
past decade has pushed back the origins of the Class Or-
endosiphuncular and cameral deposits were not includ-
thoceratoidea well into the late Tremadocian (KRÖGER
ed in the analysis. Comparison of the two trees figured
2008; KRÖGER& EVANS2011) whilst indicating that di-
by KRÖGER(2008b, fig. 3) illustrates the problem. Nev-
versification of these cephalopods was already taking
ertheless, if this group of taxa achieved their wide distri-
place in the Tremadocian (KRÖGER& EVANS2011) and
bution through (at least in part) the innovation of the
increased in the early Floian (EVANS 2005, 2011) as
small spherical protoconch, then this could provide the
demonstrated by the extended ranges of several Lau-
character that unites the Orthoceratoidea. This implies
rentian taxa (EVANS2011, and Fig. 1 herein).
that the late Tremadocian and the Floian was a period
The proposed revision of the position of the Stair- of rapid radiation for the Orthoceratoidea, much of the
sian-Tulean boundary to approximately coincide with documentation of which remains to be discovered.
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Fig. 1: Stratigraphical occurrences of members of the Orthoceratoidea in the areas forming the margins of the Iapetus Ocean during the
Early Ordovician.
2. Eothinoceratidae and Bathmoceratidae. Al- cations around Gondwana (EVANS2007; CICHOWOLSKI
though the families Eothinoceratidae and Bathmocer- & VACCARI2011; KRÖGER& EVANS2011) and certain-
atidae achieved a distribution across several palaeocon- ly underwent diversification as indicated by the assem-
tinents during the Floian and Darriwilian, the oldest blages from the Montagne Noire (KRÖGER & EVANS
member of the Eothinoceratidae known is considered to 2011). Proterocameroceras contrarium TEICHERT &
belong to Saloceras sericeum(SALTER), represented by S. GLENISTER from the Emanuel Limestone of northwest
cf. sericeum from the Floresta Formation of the Australia may belong to Saloceras (EVANS 2005, p. 11)
Cordillera Oriental of northwest Argentina (CI- or represent a new genus of eothinoceratid. Saloceras
CHOWOLSKI& VACCARI2011), and by the lost type ma- ranges into the mid and late Floian in the Welsh Basin
terial of Cyrtoceras praecoxSALTER, here considered like- (EVANS 2005) and the Central Andean Basin (CI-
ly to belong to S. sericeum (see discussion in EVANS CHOWOLSKIunpublished data).
2005, p. 67) that originated from the Dol-cyn-afon For-
The earliest records of Eothinocerasare from the lat-
mation (tennelusgraptolite biozone) of North Wales. As
est Tremadoc and earliest Floian of low latitude Gond-
the material described by CICHOWOLSKI & VACCARI
wana (Western Australia [TEICHERT & GLENISTER
(2011) came from the deltifer conodont biozone, these
1954]) and Laurentia (ULRICH et al. 1944; KRÖGER &
two records are of broadly the same age, and appear to
LANDING 2008). The occurrence of the genus in the
mark the first appearance of cephalopods in high latitu-
Rochdale Formation of New York State suggests that it
dinal Gondwana.
may be slightly older than Protothinoceras CHEN & TE-
Whilst S. sericeumappears to range up into the ear- ICHERT from the early Floian Liangchiashan Formation
ly Floian in the Welsh Basin, it is not known with cer- of Hebei Province, North China and regarded as the an-
tainty beyond this area. The genus occurs at various lo- cestor of Eothinocerasby CHEN& TEICHERT(1987, text-
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Fig. 2: Worldwide stratigraphical distribution of members of the Eothinoceratidae and Bathmoceratidae during the Early and Middle
Ordovician.
fig. 3). Nevertheless, the fauna of the Liangchiashan America, Bathmoceras is present in western Gondwana
Formation clearly records what may have been a short- from the mid-Floian to the Darriwilian and is also pres-
lived proliferation of genera that could have arisen from ent in the Southern China and the Baltic during the
Eothinoceras and probably gave rise to the Cyrto- Dapinginian and Darriwilian.
cerinidae through Tangshanoceras CHEN (CHEN & TE-
Margaritoceras CECIONI & FLOWER from the Floian
ICHERT1987). The appearance of Eothinocerasat distant
of Bolivia and SarcerdosocerasEVANSfrom the Darriwil-
locations during the latest Tremadoc and early Floian is
ian of the Welsh Basin are similar, although the latter
difficult to explain unless it is accounted for by a longer
differs in its lower rate of conch expansion, narrower si-
history of the genus or a capacity for rapid dispersal.
phuncle, and compressed ovoid cross-section (EVANS
Eothinoceras renataeCECIONI& FLOWERfrom the Floian
2005). Although they are likely to be closely related,
of Bolivia, and E. marchaense BALASHOV from the
Margaritoceras is at present known only from the Cen-
Floian of Siberia provide further evidence of this wide,
tral Andean Basin of Bolivia and northwest Argentina,
if sporadic, distribution of this genus during the Floian.
where M. diploideis now known to be present in the mid
The occurrence of Eothinoceras and Saloceras? con- Floian possibly late Floian (CICHOWOLSKI unpublished
trarium(TEICHERT& GLENISTER) in the Canning Basin data) whilst a further species of Margaritocerasis known
of Western Australia, combined with the occurrence of from the late Floian (CICHOWOLSKI unpublished data).
Bathmoceras australe (TEICHERT) from the late Floian- Additional, undescribed taxa are known from the mid-
early Dapinginian Horn Valley Siltstone (COOPER1981, Floian of the Central Andean Basin (CICHOWOLSKIun-
fig. 5), as well as further occurrences of the latter species published data). As it stands, the evidence from South
and B. taichoutenseKRÖGER& LEFEBVRE, from horizons America suggests that the Eothinoceratidae underwent
regarded as of early to mid-Floian age in Morocco a radiation at least during the Floian that appears to be
(KRÖGER& LEFEBVRE2012) make for difficulty in iden- restricted to South America, although taxa such as
tifying the ancestor of Bathmoceras.Nevertheless, when Sarcerdosocerasmay suggest that some of these lineages
all records are considered, with the exception of South later extended into Avalonia.
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Fig. 3: Stratigraphical distribution of lituitid species in Baltica during the Darriwilian, demonstrating the high resolution provided by
these taxa in comparison with trilobites, graptolites and conodonts.
The Eothinoceratidae and Bathmoceratidae were YU 1930; LAI 1982; LAI 1986; QI 1980), Korea (YUN
widely distributed around Gondwana during the Early 1999, 2002), Estonia (BALASHOV 1953), Norway
and Middle Ordovician, and where the range of a (SWEET 1958), Sweden (ANGELIN & LINDSTRÖM 1880;
species is known, may resolve to a stage or even a time- HOLM1891; KING1999) and the ‘Diluvium-Geschiebe’
slice (Fig. 2). As some inshore assemblages of high lati- of northern Poland (DZIK 1984) and Germany (BOLL
tude Gondwana (e.g. parts of the early Floian, Bolahaul 1857; NOETLING1884; REMELÉ1880, 1881). A substan-
Member of the Ogof Hên Formation of Wales) may be tial number of lituitid genera have been described since
dominated by molluscs, whilst graptolites and trilobites the 19th century (e.g. HYATT 1894; TEICHERT et al.
are relatively rare (e.g. FANG & COPE 2004), these 1964) and the taxa are firmly established within
cephalopods may have the potential to constrain ages in cephalopod literature.
some cases.
The Swedish lituitid fauna extends mainly from the
3. Lituitida. Lituitid nautiloids are common and dis- early Kundan to Uhakuan stages. This general succes-
tinctive components of Middle Ordovician cephalopod sion of taxa closely corresponds with lituitid faunas de-
faunas in the ‘Orthoceratite Limestone’ facies of Bal- scribed elsewhere, especially China (CHEN& LIU1976).
toscandia (especially Sweden) and coeval carbonate se- In the Swedish ‘Orthoceratite Limestone’ sequence,
quences, such as the Dawan Formation in China. They biostratigraphical data from the latest Volkhovian and
are virtually cosmopolitan in occurrence, and are earliest Kundan stages of Öland and Östergötland indi-
known from the USA and Newfoundland (FLOWER cate that the weakly cyrtoconic Sinoceratidae occur be-
1975), Wales (EVANS 2005, and in prep.), China (e.g. low the coiled Lituitidae. The former are represented by
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Fig. 4: Occurrence ranges of Cenocerasspecies in the Early Jurassic of southern England, compared with the standard ammonite
zonation. Inset: Cenoceras intermedium(SOWERBY, 1816), reproduced from D’ORBIGNY(1843: pl. 27, fig. 1).
Rhynchorthocerasand related genera that extend up into Within Sweden, the use of some lituitid taxa as
the Aserian and Lasnamägian stages. The earliest Litu- stratigraphical indicators has long been recognised (e.g.
itidae occur in the mid Kundan and are represented by JAANUSSON & MUTVEI 1953; JAANNUSSON 1963) and
forms such as Holmiceras praecurrens(HOLM, 1891). An- their common occurrence in some beds has given rise to
cistroceras, with its very rapidly expanding conch is former names such as ‘Ancistroceras Limestone’ (now
recorded from the late Kundan of Kinnekulle, termed Furudal Limestone). Closer examination of the
Västergötland, and extends through the Aserian and Darriwilian lituitid faunas (KING1990, unpublished and
Lasnamägian, but is more typical of and numerous in in prep.) demonstrates that these lituitids have consid-
the late Lasnamägian and Uhakuan stages. An- erable potential as zonal fossils, and achieve a resolution
gelinoceras latum (ANGELIN & LINDSTRÖM, 1880) is at least as good as, and for the Aserian and Lasnamägian
recorded only from the lower part of the Segerstad portion of the succession, potentially finer than that
Limestone (Aserian) and the maximum development currently recognised using established trilobite, grapto-
and diversity of Lituitidae is attained within the Las- lite or conodont zonal schemes (Fig. 3).
namägian-aged Seby and Folkeslunda limestones where
various species of Lituites, Trilacinocerasand Cyclolituites Silurian-Devonian
are of common occurrence.
In recent years concentrated efforts have been made
Apart from the possession of complex sutures, litu- to improve the knowledge of the distribution and tax-
itids possess all the attributes typically associated with onomy of Silurian nautiloid cephalopod faunas and
ammonoids (especially ammonites) which make them many existing collections have been revised using up to
such valuable and reliable biozonal indicators and capa- date taxonomic criteria as well as collection of new ma-
ble of biostratigraphic correlation with a high degree of terial from horizons with precise biostratigraphic data.
resolution. Namely, lituitids possess distinctive, easily Consequently systematic studies of Silurian nautiloid
recognisable conchs whose form and ornament enables cephalopods from a variety of geographical settings and
taxa to be readily distinguished; they evolved rapidly the observed temporal and spatial data from these fau-
and have a wide geographical occurrence; and although nas may now be considered a reliable tool for palaeobio-
they are more commonly found in shallow water, plat- geographical reconstruction. In Europe the main work
form carbonate sequences, they also occur in mudstone on Silurian faunas has been done in the British Isles
facies, such as those of the Llanfawr Mudstone Forma- (EVANS1994; EVANS& HOLLAND1995; HOLLAND1998,
tion of central Wales (EVANSin prep). 1999, 2000a–c, 2002, 2003, 2004, 2007, 2010; HOL-
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LAND& STRIDSBERG2004), Sweden (STRIDSBERG1985), Sphooceras truncatum(Wenlock), Pseudocycloceras dupon-
Prague Basin (DZIK1984; GNOLI1997; KOLEBABA1975, ti-Kionoceras doricum(early Ludlow) and Pseudocycloceras
1977, 1999, 2002; MANDA1996, 2008; MANDA& KŘÍŽ nereidum-Sphooceras truncatum (Ludlow). Taxa such as
2006, 2007; MANDA & TUREK 2009a,b; MAREK 1971; Deirocerasand Jovellaniahave been seen to dominate in
MAREK & TUREK 1986; STRIDSBERG & TUREK 1997; certain intervals of the Devonian in Morocco (KRÖGER
TUREK1975, 2008), South West Sardinia (GNOLI1990; 2008) and may prove useful for recognition of marker
GNOLI & SERPAGLI 1977, 1991; GNOLI & SERVENTI beds deposited within sequences.
2006, 2009 and references therein; SERPAGLI & GNOLI
There have been numerous studies of the well-
1977), Spain (BOGOLEPOVA 1998a), France (RISTEDT
known Silurian-Devonian in age ‘Orthoceras lime-
1968; SERVENTI& FEIST2009) the Carnic Alps of Aus-
stones’ or Cephalopod Limestone Biofacies both with re-
tria and Italy (BOGOLEPOVA 1998b; GNOLI & HISTON
gard to their depositional cycles and biotic content. The
1998; GNOLI& SERVENTI2008; GNOLIet al. 2000; HIS-
Carnic Alps of Austria is a key locality along the North-
TON 1997, 1998, 1999a, b, 2002, 2012a, b; RISTEDT
ern Gondwana margin regarding Silurian biostratigraph-
1968, 1969, 1971; SERVENTI& GNOLI2000; SERVENTIet
ical correlation where the Silurian Cephalopod Lime-
al. 2006, 2010) and the Graz Palaeozoic of Austria (HIS-
stone Biofacies is well preserved. The Cellon section has
TONet al. 2010). Tentative correlations are now possi-
been utilized as a geographic reference district (RD) for
ble between Avalonia (British faunas), some areas posi-
both conodont correlation studies (KLEFFNER 1989,
tioned along the Northern Gondwana Margin (Carnic
1995) and for evaluation of global eustatic changes
Alps, Sardinia, France and Spain) and Bohemia and
(JOHNSON2010) for the North Gondwana area. Recog-
Baltica, although problems do still exist in recognition
nition of environmental and water depth changes based
of faunas at both generic and specific level due to poor
on the fossil assemblages (mostly trilobites, brachiopods
preservation and lack of precise taxonomic diagnoses.
and bivalves) from the Silurian depositional sequences
Detailed study of Silurian-Devonian nautiloid fau- developed there (BRETTet al. 2009) places a tight con-
nas from Morocco by (KRÖGER2008) presented togeth- trol on small scale bioevents within well-defined con-
er with precise stratigraphic and lithofacies data for the odont (WALLISER 1964), graptolite (JAEGER 1975) and
collection localities has highlighted further exchange of chitinozoan (PRIEWALDER1997) biozones. Particular em-
faunas between Peri-Gondwana Terranes. Studies of phasis has been placed in these studies on establishing
particular taxa and nautiloid biodiversity, again within the response of marine faunas to oscillations in sea-level
precise stratigraphic biozones and detailed facies studies, and to the oceanic variations (chemistry, temperature,
in the Silurian of the Prague Basin in relation to palaeo- currents) recorded (WENZEL1997; KŘÍŽ1998, KŘÍŽet al.
biogeographical distribution and oceanic states of the 2003) during this time interval on a local scale for com-
North Gondwana area and Perunica by MANDA et al. parison with data from other North Gondwana terranes
(2009, 2010) and others (see list above) are important such as Sardinia and Bohemia and on a global scale with
contributions to these fields and confirms that nautiloid some sectors of Avalonia (the British Isles) and Lauren-
cephalopods are indeed reliable indicators for this inter- tia (North America).
val. Studies of faunas at both a local and regional scale
Correlation of the nautiloid faunal assemblages from
within single biozones are still preferable for building a
the cephalopod limestone biofacies levels and their
consistent database for future reference.
taphonomic signatures within the contexts outlined
Certain taxa show potential as biostratigraphical in- above with evidence for pronounced redox changes, sur-
dicators for the Silurian-Devonian interval as has been face currents, regression/transgression sequences within
shown by various studies (see list above): Orthocycloceras, precise intervals from the Carnic Alps (Austria) succes-
Hemicosmorthoceras, Plagiostomoceras, Pseudocycloceras, sions may identify common controlling factors in the
Columenoceras, Parakionoceras, Kionoceras,Dawsonoceras, palaeogeographic distribution and migrational routes of
Sphaerorthoceras, Temperoceras as well as representatives these faunas (HISTON 2012b). Current studies, in line
of the Phragmocerids, Oncocerids and Tarphycerids such with those of MANDA(2009), MANDA& FRYDA(2010)
as Ophioceras. Nautiloid cephalopod assemblages were and others, attempt to identify controlling factors on a
broadly defined by GNOLI & SERPAGLI (1991) and by local scale for nautiloid distribution within precise time
MANDA& KŘÍŽ(2006) using a suite of taxa which dom- slices that may then be recognized in other areas where
inated in certain Silurian series: Pseudocycloceras tran- these faunas occur along the North Gondwana Margin
siens-Columenoceras grande(Wenlock–early Ludlow), Me- (HISTON2012a). This is an on-going study done in par-
rocycloceras declive-Cryptocycloceras deludens (early Lud- allel with revision of historical collections (GNOLI &
low), Kopaninoceras thyrsus-Orthocycloceras fluminese(late HISTON1998; HISTON1999; GNOLIet al. 2000), system-
Ludlow–Pridoli/Early Devonian, Pseudocycloceras duponti- atic collection and description within precise biozones
14
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(HISTON 2002; HISTON et al. 2010) and taphonomic some species may be assigned lineages and may be com-
studies (HISTON 1999, 2002, 2012a and references pared with assemblages described by TEICHERT& KUM-
therein;). This holostratigraphical approach may pro- MEL(1973) from the Late Permian of northwest Iran.
vide further evidence for the reconstruction of reliable
nautiloid assemblages or identification of precise mark- Triassic
er taxa.
Despite the relative paucity of works on Triassic
nautiloid cephalopods, there is strong evidence of their
Carboniferous
potential value to some aspects of Triassic biostratigra-
The monographic works by HYATT, MILLERand oth- phy. KUMMEL (1953) reviewed many Triassic nautiloid
ers in the USA, SHIMANSKYin Russia, FOORDand TURN- genera, indicating their stratigraphical ranges and a po-
ER in the British Isles, and DE KONINCK from Belgium tential for their biostratigraphical use. This potential
constituted the foundations for the study on Carbonifer- has been realised through the development of a detailed
ous nautiloid cephalopods (see papers listed under refer- zonal scheme using nautiloids (SOBOLEV 1994) for the
ences). In recent years some taxonomic revision of these Boreal Triassic of Siberia. Such a scheme clearly demon-
nautiloids has been carried out (see studies listed by HIS- strates the value of the organisms as biostratigraphical
TON, MAPES, NIKO, STURGEONand others), but the use tools.
of rapidly evolving goniatite lineages to establish a bios-
tratigraphy, particularly for the Upper Carboniferous is Jurassic and Cretaceous
predominant and consideration of the stratigraphical po-
After the disappearance of seven families and ap-
tential of nautiloid cephalopods has been neglected.
proximately thirty genera during the Late Triassic ex-
However, several taxa are worthy of mention and are
tinctions (KUMMEL1964, fig. 294), only the Nautilidae,
known to to be abundant at certain intervals in a diverse
represented by the single genus Cenoceras is conven-
range of palaeogeographical settings. Large specimens of
tionally regarded as having survived into the Jurassic
Rayonnoceras are known to be markers within Lower
where it underwent a radiation that led to all subse-
Carboniferous strata of Europe and the USA where they
quent nautiloid genera including Nautilus. Analysis of
are common in the Brigantian /Mississippian. The annu-
the distribution of Middle Jurassic nautilids in western
lated Cyclocerasand taxa of the Oncocerida such as Po-
France by BRANGER(2004) indicates that the ranges of
terioceras and Welleroceras are common in the Lower
some taxa may be no more than one or two ammonite
Carboniferous. Several Pseudorthocerataceae taxa are
zones, indicating a potential utility as biostratigraphical
restricted to the Carboniferous such as Mitorthoceras.
tools. The same appears to be true for Lower Jurassic
The distinctively ornamented Brachycyclocerasis a com-
nautilids.
mon element in the Upper Carboniferous. A variety of
Historically the name Cenoceras has been broadly
coiled nautiloid taxa such as Vestinautilus, Trigonoceras,
applied to a diverse range of Late Triassic to early Mid-
Aphelaeceras, Epistroboceras, Maccoyoceras, Asymptoceras,
dle Jurassic nautilids that constitute a “plastic evolving
Acanthonautilus and Bistrialites are typical of the Lower
Carboniferous of the British Isles, Belgium, Asia and the complex” (KUMMEL1956, p. 361). It is now recognised
USA. More precise biostratigraphical data may be ob- that this masks a number of distinct lineages within a
tained through further study of the ranges of these taxa rapidly evolving nexus of Lower Jurassic nautilid faunas
at species level. However, to date, such a zonal scheme (TINTANT 1984, 1987; RULLEAU 2008). Previous work-
has not been developed. ers (HYATT 1894; SPATH 1927) recognised a number of
different morphotypes within the ‘Cenoceras complex’
Permian and provided names for several forms (including Digo-
nioceras, Ophionautilus and Sphaeronautilus). The taxo-
The papers by MILLERet al. (1942, 1949) of the Per-
nomic status of these taxa requires revision.
mian nautiloids of the USA still stand as reference
works for taxonomy of the group. However, there are More recently, TINTANT(1984) described three sub-
few studies in relation to the development of the bios- genera within Cenoceras: Cenoceras (in a restricted
tratigraphical potential of nautiloid cephalopods for this sense) for forms with relatively stout, involute conchs
interval. An investigation of the Late Permian nautiloid possessing a spiral ornament on the ventral and lateral
faunas of the Bellerophon Formation from the surfaces of the whorls; Hemicenoceras for compressed
Dolomites of Northern Italy (POSENATO & PRINOTH forms possessing spiral ornament that is mainly confined
2004, 2007; POSENATO2010) indicates that certain nau- to the ventral area, and Metacenocerasfor forms with a
tiloid taxa representing species of Tainoceras, Tirolonau- flattened venter and an ornament consisting only of
tilus, Liroceras and Foordiceras may indeed be used as weak transverse growth lines. The earliest Metaceno-
markers for precise levels within the succession whilst ceras occur in the early Sinemurian (Shales-with-Beef
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© Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at
Member, Charmouth Mudstone Formation near Lyme ic larval stage. Furthermore, the skeletal morphology of
Regis, Dorset, UK [KINGunpublished data]); Hemiceno- nautilids in general, and of these genera in particular, is
ceras is typically first encountered in the Carixian, markedly homogeneous with respect to the characters
where it is represented by H. arare(DUMORTIER, 1869) used to diagnose different species.
and H. egregium(PIA, 1914). In this paper, Cenocerasis
All these considerations suggest that attempts to use
used in the restricted sense employed by TINTANT.
Cretaceous nautilids for biostratigraphical purposes are
The Hettangian to Carixian sequence of Cenoceras likely to be disappointing. This is compounded when
malherbii (TERQUEM, 1855) – C. intermedium(SOWERBY, the long stratigraphical ranges of some of the species are
1816) – C. striatum (SOWERBY, 1817) – C. pertextum taken into consideration. Cymatoceras perstriatum
(DUMORTIER, 1867) – C. simillimum (FOORD & CRICK, (STEUER) is a typical example of such a species. C. pers-
1890) was recognised in French successions by TINTANT triatum(STEUER) occurs in strata of Tithonian-Hauteri-
(1984). In the United Kingdom, the same sequence of vian age in the Neuquén Basin (CICHOWOLSKI 2003);
taxa is present (in part) in the Lower Jurassic of South the late Tithonian-early Berriasian of the Chilean
Wales, and on the North Somerset and Dorset coasts Aconcagua platform (CORVALÁN1959; BIRÓ-BAGÓCZKY
(Fig. 4). Within this lineage there is a tendency for 1964), and the late Valanginian-early Albian of the
conchs to become more involute (from 20% in Hettan- Chañarcillo Basin (northern Chile: HOFSTETTER et al.
gian forms to <10% in Carixian taxa); for the siphuncle 1957; SEGERSTROM1960). The whorl cross-section, the
to migrate from a ventrocentral to central position; for sutural pattern, and overall shape of the conch all ex-
the whorl section to become more rounded and arched, hibit a marked ontogenetic and intraspecific variability
and less quadrate; and for suture lines to become more (CICHOWOLSKI2003). Such a range of variation implies
sinuous, culminating with C. jourdani (DUMORTIER, that an extra effort may be required in order to positive-
1874) in the Toarcian (KING2011). ly identify individual members of this particular taxon.
Late Hettangian and early Sinemurian strata on the However, there are some nautilid species possessing
Somerset coast (particularly within the angulata and easily recognisable morphologies that present low vari-
bucklandi zones) include several monotonous beds of ability within and between individuals. When such taxa
dark grey to black shales and bituminous mudstones have a relatively short stratigraphical range, and other
which are virtually devoid of ammonites. These units biostratigraphic markers are lacking, they may provide
contain fossil nautilids that are embedded in the sub- valuable information with regard to the age of the stra-
strate at orientations that range from horizontal to ver- ta in which they are found. One such example may be
tical, and provided hard attachment surfaces for a range provided by Eutrephoceras dorbygnianum (FORBES in
of organisms of which oysters and crinoids are the most DARWIN, 1846), known from the Antarctic Peninsula,
abundant. Quiriquina Island in Chile, the Austral Basin of south-
ern Argentina, and possibly from Angola (STEINMAN
Wherever ammonites are present in the Lower
1895; SPATH1953; HOWARTH1965; STINNESBECK1986;
Jurassic, by comparison, nautilids make relatively poor
CICHOWOLSKI et al. 2005; NIELSEN & SALAZAR 2011).
biostratigraphical indicators. However, when am-
This species is characterized by an almost straight su-
monites are absent, cenoceratid nautilids can be used
ture, combined with a small, acute, umbilical saddle,
for biostratigraphical purposes and provide a resolution
and a semilunate whorl cross-section (CICHOWOLSKI et
of at least stage or even substage level. Unlike Middle
al. 2005). Based on its occurrence, this species ranges
Jurassic nautilids (BRANGER2004), there are, at present,
through the Campanian and Maastrichtian, becoming
no known Lower Jurassic cenoceratid taxa that are char-
particularly abundant during the Maastrichtian. Thus,
acteristic indicators of an individual ammonite zone, al-
like the Lower Jurassic Cenoceras, the stratigraphical
though further research may change this picture.
range of some Late Cretaceous nautilids may resolve to
Cretaceous nautilids from southern South America one or two stages.
are relatively scarce and of low diversity. Most belong to
one or two genera: Cymatoceras HYATT, and Eutrepho-
Concluding remarks
cerasHYATT. Both genera possess a strongly involute, in-
flated and globose conch with an orthochoanitic, sub- This survey of the use and potential use of nautiloid
central siphuncle, as well as simple sutures. Both genera cephalopods in biostratigraphy is inevitably, incom-
are cosmopolitan in distribution, but at species level, plete. Nevertheless, examples provided by the lituitids
cosmopolitan distributions are almost nonexistent (CI- (above) and the Triassic nautiloids of Siberia (SOBOLEV
CHOLOWSKI 2003) which may reflect the nektobenthic 1994) demonstrate that when diversification rates are
habit of these animals, as well as the lack of a plankton- high, these organisms may be used to define biostrati-
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