Carboniferous

The use of multivariate statistics to determine the paleoenvironmental distribution of Lower Carboniferous Foraminifera from Ireland

by Stephen Gallagher

Late Dinantian (Lower Carboniferous) platform carbonate stratigraphy of the Buttevant area North Co. Cork, Ireland

by Stephen Gallagher

A thick sequence of late Dinantian (Asbian±Brigantian) carbonates crop out in the Buttevant area, North Co. Cork,more A thick sequence of late Dinantian (Asbian±Brigantian) carbonates crop out in the Buttevant area, North Co. Cork,
Ireland. A mud-mound unit of early Asbian age (the Hazelwood Formation) is the oldest unit described in this work.
This formation is partly laterally equivalent to, and is overlain by, over 500 m of bedded platform carbonates which
belong to the Ballyclogh and Liscarroll Limestone Formations. Four new lithostratigraphic units are described within
the platform carbonates: (i) the early Asbian Cecilstown Member and (ii) the late Asbian Dromdowney Member in
the Ballyclogh Limestone Formation; (iii) the Brigantian Templemary Member and (iv) the Coolbane Member in the
Liscarroll Limestone Formation.
The Cecilstown Member consists of cherty packstones and wackestones that are inferred to have been deposited below
fair-weather wavebase. This unit overlies and is laterally equivalent to the mud-mound build-up facies of the Hazelwood
Formation. The Dromdowney Member is typi®ed by cyclic-bedded kamaenid-rich limestones possessing shell bands,
capped by palaeokarst surfaces, with alveolar textures below and shales above these surfaces. The carbonates of this unit
were deposited at or just below fair-weather wavebase, the top of each cycle culminated in subaerial emergence. The
Templemary Member consists of cyclic alternations of subtidal crinoidal limestones capped by subtidal lagoonal crinoid-
poor, peloidal limestones possessing coral thickets. Intraclastic cherty packstones and wackestones characterize the
Coolbane Member, which is inferred to have been deposited below fair-weather wavebase but above storm wavebase.
The early Asbian Cecilstown Member has a relatively sparse micro- and macrofauna, typi®ed by scattered Siphono-
dendron thickets, archaediscids at angulatus stage and common Vissariotaxis. Conversely, macro- and microfauna is
abundant in the late Asbian Dromdowney Member. Typical late Asbian macrofossils include the coral Dibunophyllum
bipartitum and the brachiopod Davidsonina septosa. The base of the late Asbian (Cf6g Subzone) is recognized by the ®rst
appearance of the foraminifers Cribrostomum lecompteii, Koskinobigenerina and the alga Ungdarella. The Cf6g Subzone
can be subdivided into two biostratigraphic divisions, Cf6g1 and Cf6g2, that can be correlated throughout Ireland.
Relatively common gigantoproductid brachiopods and the coral Lonsdaleia duplicata occur in the Brigantian units. The
base of the Brigantian stage (Cf6d Subzone) is marked by an increase in the abundance of stellate archaediscids,
the presence of Saccamminopsis-rich horizons, Loeblichia paraammonoides, Howchinia bradyana and the rarity of
Koninckopora species.
Changes in facies at the Cecilstown/Dromdowney Member and the Ballyclogh/Liscarroll Formation boundaries
coincide closely with the changes in fossil assemblages that correspond to the early/late Asbian and the Asbian/Brigantian
boundaries. These facies changes are believed to re¯ect major changes in relative sea-level on the Irish platforms. The sea-
level variations that are inferred to have caused the facies changes at lithostratigraphic boundaries also brought in the new
taxa that de®ne biostratigraphic boundaries. Moreover, many of the Dinantian stage boundaries that are de®ned bio-
stratigraphically in Great Britain, Belgium and the Russian Platform also coincide with major facies boundaries caused
by regressive and transgressive episodes. The integration of detailed biostratigraphic analyses with facies studies will lead
to better stratigraphic correlations of Dinantian rocks in northwest Europe.

he stratigraphy and cyclicity of the late Dinantian platform carbonates in parts of southern and western Ireland

by Stephen Gallagher

Controls on the distribution of calcareous Foraminifera in the Lower Carboniferous of Ireland

by Stephen Gallagher

Biostratigraphy, microfacies and depositional environments of Upper Visean limestones from the Burren region, County Clare, Ireland

by Stephen Gallagher

Combined methodologies for three-dimensional reconstruction of fossil plants preserved in siderite nodules: Stephanospermum braidwoodensis nov. sp. (Medullosales) from the Mazon Creek lagerstätte.

by Alan R. T. Spencer

Spencer, A.R.T, Hilton, J. & Sutton, M.D. In Review. Rev. Palaeo. & Paly.

A new species of Medullosan ovule from the Mazon Creek Carboniferous lagerstätte is documented using a novel... more A new species of Medullosan ovule from the Mazon Creek Carboniferous lagerstätte is documented using a novel combination of non-invasive X-Ray Micro-Tomography (XMT) and orientated precision sectioning based on the XMT results. 3-D reconstruction of the ovule has correlated geometries of different layers with tissue characteristics gathered from wafered sections, with the methodological combination presenting a virtual reconstruction of the specimen and also enabling positioning of serial sections of the holotype in pre-determined positions. Stephanospermum braidwoodensis sp. nov. has four longitudinally orientated sarcotestal wings, two to each side of the major plane that demonstrate 180° rotational (bilateral) symmetry, while the sclerotesta has three prominent longitudinal commissural ribs and the pollen chamber has three small ribs and triangular nucellar beak, both demonstrating radial (threefold) symmetry. This demonstration of both radial and bilateral symmetries in different tissues emphasises the complexities of inferring systematic affinities of fossil seeds from symmetry alone. We consider S. braidwoodensis to be closely related to the co-occurring S. konopeonus Drinnan et al., and postulate that it was born on a fertile truss similar to that of the latter species. Finally implications of our findings for the utility of these methods in identifying additional species from the Mazon Creek biota are discussed, and the advantages and disadvantages of different methods of nodule preparation are considered. We conclude that additional species are likely to be recognised from the Mazon Creek flora by application of the same methodologies used in this investigation.

The geology and terrestrial life of the Carboniferous.

by Alan R. T. Spencer

Garwood, R.J. & Spencer, A. 2011. The geology and terrestrial life of the Carboniferous. Deposits Magazine. 28:38-47

The Carboniferous Period is a fascinating time in earth history. It spanned 60myrs (359.2 to 299.0mya), towards the... more The Carboniferous Period is a fascinating time in earth history. It spanned 60myrs (359.2 to 299.0mya), towards the end of the Palaeozoic era, falling between the Devonian and Permian. During the Carboniferous, the supercontinent Pangaea was assembling and the oceans were home to invertebrates such as corals, bryozoa, ammonoids, echinoderms, trilobites and crustaceans. Fish were also well represented (especially sharks), which were rapidly diversifying at the time. The continents were no barren wasteland either – they were host to some of the first widespread terrestrial forest and swamp ecosystems. In these lived both invertebrates, which had crawled onto land by the Silurian period (at least 423mya) and vertebrates, which were relative newcomers to this realm. This article provides us with an excuse to write about the Carboniferous. We will first introduce the geology and palaeogeography of the Carboniferous, including an overview of the most common mode of preservation we see in terrestrial fossils. Then, we will provide an overview of terrestrial life during the period, as land-based ecosystems of this age are among the best known from the Palaeozoic and an exciting time in the history of life.

The Late Palaeozoic trilobites of Iran and Armenia and their palaeogeographical significance.

by Rudy Lerosey-Aubril

LEROSEY-AUBRIL, R. in press. The Late Palaeozoic trilobites of Iran and Armenia and their palaeogeographical significance. Geological Magazine.

The Iranian territory is composed of a mosaic of tectonic units, several of which underwent in the Permian and... more The Iranian territory is composed of a mosaic of tectonic units, several of which underwent in the Permian and Triassic periods a migration from northern Gondwana to southern Laurussia associated with the opening of the Neo-Tethys Ocean. Although this broad outline of Permo-Triassic palaeogeographical evolution of Iranian microplates is now widely accepted, the individual timing of migration of these blocks, and their biogeographical relationships, remain insufficiently known. Here I review the Late Palaeozoic record of trilobites in Iran and Armenia, and discuss their palaeobiogeographical affinities in an attempt to shed light on the Permian palaeogeographical evolution of Iranian and Armenian terranes. Seven Iranian or Armenian localities, representative of five tectonic units, have yielded Carboniferous and Permian trilobites. Ten species are recognized, including two new taxa, Persia praecox gen. nov. sp. nov. and Pseudophillipsia (s.l.) parvizii sp. nov. P. praecox is the only Carboniferous (Tournaisian) species. The others are Wordian to Wuchiapingian in age and can be separated into three morphological groups, probably representing clades. One is composed of representatives of Acropyge, while the two others (armenica-group and paffenholzi-group) comprise species of Pseudophillipsia. Only P. (s.l.) parvizii sp. nov. from the Zagros Mountains (Arabian Plate) is not attributed to one of these groups. The distribution of trilobites in Iran and Armenia strongly suggests that the Alborz, Central Iran, and Transcaucasia microplates represented a single biogeographical unit in the Middle and Late Permian. Special relationships of this biochore with South China can also be stressed.

Quantitative approach of diversity and decline in late Palaeozoic trilobites. (PDF available on request)

by Rudy Lerosey-Aubril

LEROSEY-AUBRIL R. & FEIST R. 2012. Quantitative approach of diversity and decline in late Palaeozoic trilobites. In: Talent, J.A. (Ed.), Earth and Life: Global Biodiversity, Extinction Intervals and Biogeographic Perturbations through Time, pp. 535-555. Springer Publishing.

Quantitative data reveal a complex evolution of late trilobite diversity. In the Mid- to early Late Devonian, a series... more Quantitative data reveal a complex evolution of late trilobite diversity. In the Mid- to early Late Devonian, a series of extinction events led to a drastic taxonomic impoverishment. In the Famennian, while only two orders remained, originations started to compensate still high extinction rates marking the onset of a remarkable diversification. Though interrupted by the major Hangenberg turnover, the general diversification trend accelerated in the Tournaisian whilst extinctions became modest. Originations notably diminished during the Viséan and the Serphukovian, making the diversity to step down at the level of the Frasnian. It has never been much higher thereafter, despite a profound restructuring of trilobite communities in the early Pennsylvanian permitting the progressive domination of ditomopygines. After another drop in the Kasimovian a period of stasis occurred with very low diversity levels and almost no renewal. The last diversification burst took place in the Wordian, but it ceased rapidly in the Capitanian when the degradation of environmental conditions started to inhibit originations. Thus, the extinction of the Trilobita at the end of the Permian resulted from the disappearance of merely a handful of genera.

First record of the Carboniferous trilobite Bollandia from the Moravian Karst (Czech Republic) and its significance.

by Rudy Lerosey-Aubril

RAK Š. & LEROSEY-AUBRIL R. 2009. First record of the Carboniferous trilobite Bollandia from the Moravian Karst (Czech Republic) and its significance. Bulletin of Geosciences, 84(4): 741-746.

The presence of bollandiine trilobites is reported for the first time in the early Carboniferous of Moravia, the Czech... more The presence of bollandiine trilobites is reported for the first time in the early Carboniferous of Moravia, the Czech Republic. Bollandia persephone (Hahn & Hahn, 1970) and B. cf. megaira (Hahn & Hahn, 1970) were recovered from pelitic shales of late Tournaisian age within the Březina Formation exposed in Mokrá quarry, near Brno. Along with other taxa, these two species constitute a trilobite assemblage with few affinities to other Carboniferous associations known from the Czech Republic, but resemble an assemblage from the late Tournaisian of the Harz Mountains. Morphological characters of Bollandia species are interpreted as being indicative of an epibenthic mode of life, with possible adaptations for digging and for predatory/scavenging feeding habits.

First Carboniferous protaspid larvae (Trilobita)

by Rudy Lerosey-Aubril

LEROSEY-AUBRIL R. & FEIST R. 2005. First Carboniferous protaspid larvae (Trilobita). Journal of Paleontology, 79(4): 702-718.

The recovery of well-preserved silicified larvae from the early Tournaisian of Montagne Noire, southern France, allows... more The recovery of well-preserved silicified larvae from the early Tournaisian of Montagne Noire, southern France, allows the first description of the early ontogeny of proetoid trilobites, survivors of the end-Devonian Hangenberg extinction event. The fauna comprises various taxa that can only partly and tentatively be assigned to the genera Liobolina, Diacoryphe, and Pedinocoryphe without specific attribution. The close resemblance of these larvae to previously described proetoid larvae from the Ordovician and Devonian emphasizes the ontogenetic homogeneity of this superfamily. Moreover, it supports the view that the Proetida is composed of two clades: the Aulacopleuroidea / Bathyuroidea group and the Proetoidea. The Carboniferous anaprotaspides exhibit an unusually wide size range that may provide evidence of the acquisition of an extended planktonic period in the early ontogeny of at least some Carboniferous proetoids. This change in the ontogenetic strategy may have enabled proetoid trilobites to survive during the end-Devonian biocrises.

A reevaluation of early amniote phylogeny

by Michel Laurin

The evolution of body size, Cope's rule and the origin of amniotes

by Michel Laurin

Cranial morphology and affinities of Microbrachis, and a reappraisal of the phylogeny and lifestyle of the first amphibians

by Michel Laurin

Anatomy and relationships of Haptodus garnettensis, a Pennsylvanian synapsid from Kansas

by Michel Laurin

The importance of global parsimony and historical bias in understanding tetrapod evolution. Part II. Vertebral centrum, costal ventilation, and paedomorphosis

by Michel Laurin

The oldest stegocephalian from the Iberian Peninsula: evidence that temnospondyls were euryhaline

by Michel Laurin

The osteology and relationships of Haptodus garnettensis and the origin of therapsids

by Michel Laurin

Phylogeny and Apomorphies of Temnospondyls

by Michel Laurin

How Vertebrates Left the Water

by Michel Laurin