Crag Formation Research Articles

Macaque molar from the Red Crag Formation, Waldringfield, England

Fossil monkeys are rare in the British palaeontological record, a few specimens having been reported from the Pleistocene, and a single specimen from the Red Crag, possibly of Late Miocene or Pliocene age. An undescribed monkey tooth from the Red Crag at Waldringfield collected circa 1908 that has remained unidentified in the collections of the Sedgwick Museum, Cambridge, is described herein. The fossil was associated with dental remains of a suid, a tapir and a deer which, taken as an assemblage, are best correlated to the Early Pliocene, being similar to specimens from Perrier, France. Because of the high latitudinal position of Waldringfield (52°N) and indications for a tropical to sub-tropical palaeoenvironment during the Late Miocene – Early Pliocene, the monkey tooth from there is of great interest.

Reconstructing Terrestrial Paleoclimates: A Comparison of the Co‐Existence Approach, Bayesian and Probability Reconstruction Techniques Using the UK Neogene

AbstractNeogene sediments in the UK are ideally situated for understanding the early development of hydrological dynamics and atmospheric circulation that led to the modern oceanic climate of northwest Europe. Onshore Neogene fossiliferous deposits in the UK are limited to the solution pipe fills at Trwyn y Parc in Anglesey (Middle Miocene), the Brassington Formation of Derbyshire (Serravallian‐Tortonian), and the Coralline Crag Formation (latest Zanclean‐earliest Piacenzian) and Red Crag Formation (Piacenzian‐Gelasian) in southeast England. Palynoflora from these localities can be used to provide snapshots into the climate at the time of deposition, however, palaeobotanical‐based reconstructions are typically lacking in their poor estimation of error. Therefore, we present the first pre‐Quaternary application of two terrestrial climate reconstruction techniques: CREST (Climate Reconstruction SofTware) and CRACLE (Climate Reconstruction Analysis using Coexistence Likelihood Estimation), that use Bayesian and likelihood estimation probability respectively to generate a new palaeoclimate reconstruction, and compare this to Co‐existence Approach reconstructions from the UK and continental Europe. Our study shows how Mean Annual Temperature (MAT) declines by 3°–6°C, Mean Annual Precipitation (MAP) declines by 480–600 mm and Precipitation Seasonality approximately halves throughout the Neogene. CREST and CRACLE reconstructions overlap with the Co‐exisence Approach and have the advantage of providing uncertainty, rather than ranges. The UK appears to have had a milder, wetter, and less seasonal climate than continental Europe. This is likely due to the buffering effects of the Atlantic Ocean and North Sea ameliorating the UK Neogene climate despite regional and global changes in atmospheric and oceanic circulation.

Strukturalne, litologiczne oraz tektoniczne uwarunkowania rozwoju i ewolucji świętokrzyskich skałek piaskowcowych

Structural, lithological and tectonic constraints on the development and evolution of sandstone tors in the Świetokrzyskie (Holy Cross) Mountains. A b s t r a c t. Majority of ca. 90 sites of sandstone crag groups and individual crags, occurring in the Świetokrzyskie (Holy Cross) Mts. region, represent the following crag-forming lithostratigraphic units: Cambrian Wiśniowka Formation, Devonian Barcza Fm and Zagorze Fm, Triassic Zagnansk Fm and Krynki Beds, as well as Jurassic Skloby Fm and Ostrowiec Fm. Specific features of these rocks are the occurrence of sandstone series, up to 20 m thick, above more plastic, clayey or heterolithic series, high-energy depositional environments, and siliceous composition. The crag-forming sandstones differ in the amount of siliceous cement: from strongly cemented Paleozoic quartzitic sandstones to porous Mesozoic sandstones with poor cement, which determines diverse mechanical properties. Strongly cemented Paleozoic rocks display high rock strength and abrasion resistance, while porous and theoretically friable Mesozoic sandstones are characterised by high grain packing due to compaction. Regarding the principal role of gravitational disintegration of rock massifs under the periglacial conditions in the Pleistocene, other factors constraining the crag formation and shaping are the tectonic situation of rocks (orientation of strata and joints), adequate joint spacing, and bed thickness. The interrelations between lithological and structural features of crag-forming sandstones and tectonics, conditioning erosion and weathering rates are specific for particular types of these sandstones.

A guide to the fossil Decapoda (Crustacea: Axiidea, Anomura, Brachyura) of the British Isles

Ranging from the Jurassic to the Pleistocene, the fossil record of decapod crustaceans in the British Isles is extensive, comprised of 159 species (including those in open nomenclature) assigned to 101 genera. Preservation is variable, but most taxa are based upon carapace material; the study of disarticulated limb elements has added surprisingly little to the known diversity. No new taxa are erected herein, but some species have been reassigned to more appropriate genera and/or families. The stratigraphic distribution of these crustaceans is such that most, if not all, species are known from the Mesozoic and Cenozoic successions of southern and eastern England. Some areas and horizons are particularly rich in decapod species, including the Aptian Atherfield Clay Formation, Isle of Wight; the Albian Gault Clay Formation; the Cenomanian Beer Head Limestone Formation, Wilmington Sands Member; the Lower Eocene London Clay Formation; the Paleogene of the Isle of Wight; and the various crag formations of East Anglia.

Where does the time go? Assessing the chronostratigraphic fidelity of sedimentary geological outcrops in the Pliocene–Pleistocene Red Crag Formation, eastern England

It is widely understood that Earth's stratigraphic record is an incomplete record of time, but the implications that this has for interpreting sedimentary outcrop have received little attention. Here we consider how time is preserved at outcrop using the Neogene–Quaternary Red Crag Formation, England. The Red Crag Formation hosts sedimentological and ichnological proxies that can be used to assess the time taken to accumulate outcrop expressions of strata, as ancient depositional environments fluctuated between states of deposition, erosion and stasis. We use these to estimate how much time is preserved at outcrop scale and find that every outcrop provides only a vanishingly small window onto unanchored weeks to months within the 600–800 kyr of ‘Crag-time’. Much of the apparently missing time may be accounted for by the parts of the formation at subcrop, rather than outcrop: stratigraphic time has not been lost, but is hidden. The time-completeness of the Red Crag Formation at outcrop appears analogous to that recorded in much older rock units, implying that direct comparison between strata of all ages is valid and that perceived stratigraphic incompleteness is an inconsequential barrier to viewing the outcrop sedimentary-stratigraphic record as a truthful chronicle of Earth history. Supplementary material: Further details of the regional geology and specific information on outcrops are available at https://doi.org/10.6084/m9.figshare.c.4561001

The Widdington Sands: High-level Kesgrave Sands and Gravels near the Cam-Stort interfluve, Northwest Essex, UK

A small but stratigraphically significant exposure of Quaternary sandy sediments (Widdington Sands) was observed and recorded in the early 1970s in northwest Essex. These data are here re-examined and re-evaluated, yielding new insights into early proto-Thames aggradation following the marine recession of the Norwich Crag Formation (MIS 74–71, about 2 Ma). As the proto-Thames trajectory shifted south eastwards, a period of landscape stability ensued in the early Middle Pleistocene (MIS 19–13) during which the Valley Farm Soil was formed. This and the succeeding Barham Soil can be recognised in the stratigraphy, the second palaeosol heralding the arrival of glaciation in the Anglian Stage (MIS 12, 480–420 ka). These pedogenic signatures are enclosed within palaeokarstic features in the form of infilled sinkhole pipes. A large doline has functioned as a sediment trap preserving pre-truncation structures including reverse ring faults. These confirm basal support removal leading to upward migration of a dissolution cavity and roof collapse within the sinkhole pipe. The process and timing of subsidence can thus be defined more clearly than for similar features found in comparable Kesgrave aggradations of the Middle Thames. The likely glacitectonic origin of the planar sub-till surface is examined and discussed. Dating of Early Pleistocene fluvial activity is constrained by estimating the height of a former terrace surface whose elevation points to a correlation with the higher Stoke Row Member (MIS 64, 1.8 Ma), suggesting the oldest known proto-Thames activity within southern East Anglia.

Mid Campanian‐Lower Maastrichtian magnetostratigraphy of the James Ross Basin, Antarctica: Chronostratigraphical implications

AbstractThe James Ross Basin, in the northern Antarctic Peninsula, exposes which is probably the world thickest and most complete Late Cretaceous sedimentary succession of southern high latitudes. Despite its very good exposures and varied and abundant fossil fauna, precise chronological determination of its infill is still lacking. We report results from a magnetostratigraphic study on shelfal sedimentary rocks of the Marambio Group, southeastern James Ross Basin, Antarctica. The succession studied covers a ~1,200 m‐thick stratigraphic interval within the Hamilton Point, Sanctuary Cliffs and Karlsen Cliffs Members of the Snow Hill Island Formation, the Haslum Crag Formation, and the lower López de Bertodano Formation. The basic chronological reference framework is given by ammonite assemblages, which indicate a Late Campanian – Early Maastrichtian age for the studied units. Magnetostratigraphic samples were obtained from five partial sections located on James Ross and Snow Hill islands, the results from which agree partially with this previous biostratigraphical framework. Seven geomagnetic polarity reversals are identified in this work, allowing to identify the Chron C32/C33 boundary in Ammonite Assemblage 8‐1, confirming the Late Campanian age of the Hamilton Point Member. However, the identification of the Chron C32/C31 boundary in Ammonite Assemblage 8‐2 assigns the base of the Sanctuary Cliffs Member to the early Maastrichtian, which differs from the Late Campanian age previously assigned by ammonite biostratigraphy. This magnetostratigraphy spans ~14 Ma of sedimentary succession and together with previous partial magnetostratigraphies on Early‐Mid Campanian and Middle Maastrichtian to Danian columns permits a complete and continuous record of the Late Cretaceous distal deposits of the James Ross Basin. This provides the required chronological resolution to solve the intra‐basin and global correlation problems of the Late Cretaceous in the Southern Hemisphere in general and in the Weddellian province in particular, given by endemism and diachronic extinctions on invertebrate fossils, including ammonites. The new chronostratigraphic scheme allowed us to calculate sediment accumulation rates for almost the entire Late Cretaceous infill of the distal James Ross Basin (the Marambio Group), showing a monotonous accumulation for more than 8 Myr during the upper Campanian and a dramatic increase during the early Maastrichtian, controlled by tectonic and/or eustatic causes.

Marine climate and hydrography of the Coralline Crag (early Pliocene, UK): isotopic evidence from 16 benthic invertebrate taxa

The taxonomic composition of the biota of the Coralline Crag Formation (early Pliocene, eastern England) provides conflicting evidence of seawater temperature during deposition, some taxa indicating cool temperate conditions by analogy with modern representatives or relatives, others warm temperate to subtropical/tropical conditions. Previous isotopic (δ18O) evidence of seasonal seafloor temperatures from serial ontogenetic sampling of bivalve mollusk shells indicated cool temperate winter (<10 °C) and/or summer (<20 °C) conditions but was limited to nine profiles from two species, one ranging into and one occurring exclusively in cool temperate settings at present. We supplement these results with six further profiles from the species concerned and supply seven more from three other taxa (two supposedly indicative of warm waters) to provide an expanded and more balanced database. We also supply isotopic temperature estimates from 81 spot and whole-shell samples from these five taxa and 11 others, encompassing ‘warm’, ‘cool’ and ‘eurythermal’ forms by analogy with modern representatives or relatives. Preservation tests show no shell alteration. Subject to reasonable assumptions about water δ18O, the shell δ18O data either strongly indicate or are at least consistent with cool temperate seafloor conditions. The subtropical/tropical conditions suggested by the presence of the bryozoan Metrarabdotos did not exist. Microgrowth-increment and δ13C evidence indicate summer water-column stratification during deposition of the Ramsholt Member, unlike in the adjacent southern North Sea at present (well mixed due to shallow depth and strong tidal currents). Summer maximum surface temperature was probably about 5 °C above seafloor temperature and thus often slightly higher than now (17–19 °C rather than 16–17 °C), but only sometimes in the warm temperate range. Winter minimum surface temperature was below 10 °C and possibly the same as at present (6–7 °C). An expanded surface temperature range compared to now may reflect withdrawal of oceanic heat supply in conjunction with higher global temperature.

The geological constraints of the development of sandstone landforms in Central Europe, a case study of the Świętokrzyskie (Holy Cross) Mountains, Poland

Eighty sites of crag groups and individual crags occurring in the Świętokrzyskie (Holy Cross) Mts., upland situated in central Poland, were described in detail in order to examine the lithological, structural, mechanic properties and the tectonic features of sandstones and quartzites representing six crag-forming lithostratigraphic units: Cambrian quartzites, Devonian quartzitic sandstones, Triassic and Jurassic sandstones. Specific features of these rocks are: their occurrence within the sequences consisting of different rock series, high energy depositional environments and siliceous composition. The cragforming rocks differ in the amount of cement (from strongly cemented quartzites to very porous sandstones with poor cement), which determines the diverse mechanical properties (from very strong to friable rocks). The crucial feature enabling formation of crags built of porous and friable sandstones is very dense grain packing due to chemical and mechanical compaction. Regarding the principal role of the gravitational disintegration of rock massifs under the periglacial conditions in the Late Pleistocene, other factors constraining the crag formation and shaping are: the tectonic situation of rocks (the orientation of strata and joints) as well as adequate joint spacing and bed thickness. Petrographic, structural and tectonic features are interrelated.

Revised biostratigraphic scheme for the Early Pleistocene of the UK based on arvicolids (Mammalia, Rodentia)

This paper reviews the Early Pleistocene arvicolids from the UK, including new material, and updating the taxonomy and the stratigraphic interpretations. The biostratigraphic system for the Pliocene and Early Pleistocene proposed by Tesakov for southeast Europe is applied to the UK assemblages. Previous work which recognized three faunal groups is confirmed. The latest assemblages, from the ‘Weybourne Crag’ deposits (currently included in the Wroxham Crag Formation), fall within arvicolid biozone MNR1. The earlier arvicolids, from the Norwich Crag, fall within biozone MNR2, in two distinct levels. The later level, dating from the second half of biozone MNR2, includes the arvicolids from deposits exposed on the Suffolk coast near Southwold, including Easton Bavents. These underlie deposits previously assigned to the Baventian Stage. The earlier arvicolid assemblages date from the first part of biozone MNR2 (or just possibly the end of biozone MNR3) and come from Norwich Crag Formation deposits including the type Bramertonian (Bramerton, Norfolk), as well as deposits at and near the surface in the area of Sizewell (Suffolk). On the basis of palaeomagnetic calibration in southeast Europe, the three levels of the UK sequence are interpreted as corresponding to approximate absolute age limits of 2.1–2.25 Ma (‘Weybourne Crag’), 2.25–2.35 Ma (the later Norwich Crag Formation) and 2.35–2.45 Ma (the earlier Norwich Crag Formation). The revised arvicolid biostratigraphy is considered to be valid for the North Sea Basin area, allowing correlation with deposits in the Netherlands, and a link to be made between continental and marine biostratigraphic schemes. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Early Middle Pleistocene sediments at Sidestrand, northeast Norfolk, yield the most extensive preglacial cold stage beetle assemblage from Britain

Fluvial sediments (Cromer Forest-bed Formation) at Sidestrand, northeast Norfolk, have yielded the most extensive preglacial early Middle Pleistocene cold (arctic) stage beetle assemblage known from Britain. The assemblage is composed of 59 taxa indicating severely cold and continental climatic conditions. Mutual Climatic Range reconstructions suggest that the mean temperature of the warmest month (July) was between 10 °C and 13 °C and the mean temperature of the coldest months (January and February) between −17 °C and −10 °C, although the actual palaeotemperatures were probably towards the lower end of these ranges. Associated pollen and macroflora remains were poorly represented but all are known from other cold stage contexts.Excavations reveal that this freshwater arctic assemblage occurs within units between two important stratigraphic marker horizons, the Sidestrand Hall Member of the Cromer Forest-bed Formation and the first lowland glacigenic deposit (Happisburgh Till Member) in eastern England, although the ages of both remain equivocal. Recent amino-acid chronologies of molluscan faunas from the Sidestrand Hall Member indicate a MIS 13 age, with by inference a MIS 12 age for the overlying arctic units with cold beetle fauna and for the Happisburgh Till Member. However, the arctic units are separated from the two stratigraphic marker horizons by shallow marine deposits (Wroxham Crag Formation) demonstrating at least two intervening phases of marine transgression and a cold climate marine regression. The climatic significance of these marine transgressions and their chronostratigraphic implications are currently uncertain.

An illustrated guide to the fossil barnacles (Cirripedia) from the Crags (Plio-Pleistocene) of East Anglia

The Plio-Pleistocene Crag deposits of East Anglia include a wealth of shelly remains, including barnacles, preserved variously as complete shells, their disarticulated plates and trace fossils. Herein, we present a field guide to these distinctive fossils, with diagnoses of all known taxa recorded from the Crags of East Anglia, supported by both line drawings and photographs. The known stratigraphic and geographic distribution within the study area are tabulated. Recognised species include the sessile barnacles Armatobalanus bisulcatus (Darwin), A. dolossus (Darwin), Balanus balanus (Linné), B. crenatus Bruguière, B. inclusus Darwin, Concavus concavus (Bronn), Chirona hameri (Ascanius), Megabalanus tintinnabulum (Linné), Conopea calceola (Ellis), Co. spongicola (Brown), Acasta undulata Darwin, Coronula barbara Darwin, Megatrema anglicum (G.B. Sowerby) and Verruca stroemia (Müller) (=14 species); two pedunculate forms, Scalpellum magnum Darwin and Lepas delicatula Withers; and the boring Rogerella isp. The greatest diversity of species is found in the Coralline Crag and Red Crag formations, both yielding 11 species, although only four are common to both. Barnacles are poorly represented in other Crag deposits.

Fluvial deposits within the Pleistocene Crag at Thorpe St Andrew, Norwich, England

Abstract This paper records the findings at a temporary exposure at Thorpe St Andrew near Norwich, Norfolk, UK in Early and early Middle Pleistocene Crag deposits. The British Geological Survey (BGS) describes the particular formation exposed as Norwich Crag consisting of Early Pleistocene shallow marine sediments. The section shows a succession of sorted sands and gravels overlain by a sandy diamicton. Based on field evidence and clast analysis, the sands and gravels are interpreted as the product of point bar and overbank sedimentation and represent the product of a river cutting into and aggrading within the more widespread shallow marine deposits. Composition of the sediments indicates derivation, primarily from Wroxham Crag Formation, with a contribution from Norwich Crag. The sandy diamicton is interpreted as late Middle Pleistocene Corton Till that is recorded in the area. A distinct pattern of colour changes at the top of the sands and gravels is interpreted as a soil that developed on the fluvial sediments before being overridden by the glacier that deposited the Corton Till. The existence of the fluvial sediments within the regional shallow marine deposits suggests that a fall of sea-level, possibly due to climate cooling, while the elevation of the sediments and the adjacent Crag implies that the site has been uplifted since sedimentation. This is the first observation of terrestrial sediments within the shallow marine Crag. The paper also makes a contribution to understanding the diagenetic processes that give deposits within this region some distinctive colour and sediment patterns.

Finichnus, a new name for the ichnogenus Leptichnus Taylor, Wilson and Bromley, 1999, preoccupied by Leptichnus Simroth, 1896 (Mollusca, Gastropoda)

Tayloret al. (1999) proposed the ichnogenus Leptichnus for etching pits made by cheilostome bryozoans on calcareous substrates. Leptichnus has a Cretaceous (Maastrichtian) to Holocene range. The type ichnospecies is Leptichnus peristroma, with a holotype from the Coralline Crag Formation, Ramsholt Member (Pliocene), near Orford, Suffolk, England. Another ichnospecies named in the same paper is Leptichnus dromeus, with a holotype from the same locality. A third ichnospecies of Leptichnus, L. tortus, was named and described by Rosso (2008) from Upper Pleistocene sediments on the bottom of the Ionian Sea. We have recently learned that the name Leptichnus is preoccupied by a urocyclid terrestrial gastropod, LeptichnusSimroth, 1896, found in Kenya and Tanzania. The author, Heinrich Rudolf Simroth (1851–1917), apparently used the Greek roots leptos (‘flimsy, delicate, subtle’) and ichnos (‘track, footprint’) to note the narrow foot (and hence trail) of this African slug. Taylor et al. (1999) used the same roots in recognition of the shallow, delicate nature of the cheilostome etching pits. The descriptions of both taxa meet the requirements of the International Commission on Zoological Nomenclature (fourth edition of the International Code of Zoological Nomenclature, 1999). The ichnogenus LeptichnusTaylor, Wilson and Bromley, 1999, is thus a junior homonym of the gastropod genus LeptichnusSimroth, 1896. We propose the new name Finichnus nom. nov. to replace LeptichnusTaylor, Wilson and Bromley, 1999. To preserve the meaning of the original name, we are substituting the Greek finos (‘fine, delicate’) for leptos. The type ichnospecies of Finichnus is Leptichnus peristromaTaylor, Wilson and Bromley, 1999, by original designation. Editor. Sally Thomas

West European arvicolid evidence of intercontinental connections during the Early Pleistocene

Abstract Early Pleistocene arvicolid faunas from the Norwich Crag Formation of the UK contain species found across Eurasia, indicating that this was then a single faunal province. Several examples of arvicolid evidence for intercontinental connections are discussed, with reference particularly to new material from the locality Easton Wood, Suffolk, UK. This includes teeth referred to Mimomys glendae sp.nov., apparently closely related to Siberian and North American species. The locality also provides the earliest UK occurrences of Lemmus kowalskii and Mimomys tigliensis , a wide ranging and biostratigraphically important species. The immigration of M. tigliensis to West Europe took place in arvicolid zone MNR2 at a time apparently close to its appearance in Russian faunas. The faunas from Easton Wood and the Netherlands support the current arvicolid Early Pleistocene biozonation of South East Europe suggesting that it is applicable to at least the northern part of West Europe. The age of the Norwich Crag deposits at Easton Wood is estimated according to this scheme at between 2.25 and 2.35 Ma, indicating that palaeomagnetic inferences previously used to support a younger age require review.

The molluscan fauna of the Coralline Crag (Pliocene, Zanclean) at Raydon Hall, Suffolk, UK: Palaeoecological significance reassessed

This study assesses the environmental implications of a quantitative study of the unusually well preserved molluscan fauna of over 200 species (about 47% extinct) from six samples from both the Ramsholt and Sudbourne Members of the Coralline Crag Formation at a British Geological Survey borehole at Raydon Hall, near Orford, Suffolk, UK. It reveals a shallow shelf fauna locally transported from a variety of habitats dominated by infaunal species ( Spisula, Turritella, Abra, Amyclina) from relatively fine sediments, plus epifauna (especially Heteranomia) possibly in part originating from nearby bryozoan communities as well as dead bivalve shells. There was a small but consistent component of deeper water elements, such as Limopsis, and a lack of strictly littoral species. Overall, a water depth of about 50 m is suggested, with bottom temperatures at times perhaps warmer than the present southern North Sea (but not as high as the modern Mediterranean), and a more oceanic setting. This is in contrast to inferences from previous nineteenth century studies of Coralline Crag molluscs, which viewed it as largely Mediterranean in character, but understated the regular presence of boreal forms such as Arctica. Current interpretations still have to account for the coexistence of some Lusitanian or Mediterranean molluscan taxa alongside the cooler water elements.

Possible ice-rafted erratics in late Early to early Middle Pleistocene shallow marine and coastal deposits in northeast Norfolk, UK

Erratic clasts with a mass of up to 15 kg are described from preglacial shallow marine and coastal deposits (Wroxham Crag Formation) in northeast Norfolk. Detailed examination of their petrology has enabled them to be provenanced to northern Britain and southern Norway. Their clustered occurrence in coastal sediments in Norfolk is believed to be the product of ice-rafting from glacier incursions into the North Sea from eastern Scotland and southern Norway, and their subsequent grounding and melting within coastal areas of what is now north Norfolk. The precise timing of these restricted glaciations is difficult to determine. However, the relationship of the erratics to the biostratigraphic record and the first major expansion of ice into the North Sea suggest these events occurred during at least one glaciation between the late Early Pleistocene and early Middle Pleistocene (c. 1.1–0.6 Ma). In contrast to the late Middle (Anglian) and Late Pleistocene (Last Glacial Maximum) glaciations, where the North Sea was largely devoid of extensive marine conditions, the presence of far-travelled ice-rafted materials implies that earlier cold stage sea-levels were considerably higher.

Systematics of the Miocene-Recent bryozoan genusPentapora(Cheilostomata)

The four existing species of the ascophoran bryozoan Pentapora Fisher, 1807 are revised, and two new fossil species are introduced: Pentapora lacryma sp. nov. from the Pliocene Coralline Crag Formation of Suffolk, and Pentapora clipeus sp. nov. from the Pliocene of Emilia, Italy. The Arctic species Pentapora boreale Kuklinski & Hayward possesses a lyrula, does not belong in Pentapora, and is a junior synonym of Raymondcia rigida (Lorenz). The morphology of the autozooids is relatively uniform within the genus, and the main distinguishing characters are those of the ovicells and, particularly, the giant avicularia that are developed sporadically in all species apart from Pentapora foliacea, popularly known as ‘Ross coral’. A phylogenetic analysis based on skeletal characters returned a single shortest tree in which the three species of Pentapora from the North Atlantic (P. foliacea, Pentapora pertusa, and P. lacryma sp. nov.) form a clade crownward of the three basal species from the Mediterranean (Pentapora ottomulleriana, Pentapora fascialis, and P. clipeus sp. nov.). © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160, 17–39.

The Phylogeny and Palaeozoogeography of Cold-Water Species of Ostracod (Crustacea) from the Pre-Ludhamian Stage (Late Pliocene-Early Pleistocene), Red Crag Formation, East Anglia, England; with Reference to the Earliest Arrival of Pacific Species

The Pliocene Epoch represents a significant period in the palaeozoogeography of North Atlantic, Arctic and northern Pacific podocopid ostracods. A climate crash during Marine Isotope Stage (MIS) G6 (c. 2.74 Ma) resulted in the extinction of early-mid Pliocene thermophilic ostracods and the subsequent emergence of oligothermal assemblages during the late Pliocene. During the numerous cold stages of the late Pliocene-early Pleistocene Arctic ostracod species were able to disperse southwards into the mid-latitudes of the North Atlantic. The Pre-Ludhamian Stage of the Red Crag Formation, Suffolk, England spans one such episode (c. 2.7–2.41 Ma) and thus offers new insight into the vagility of shallow marine ostracods as they responded to glacio-eustatic and isostatic changes. Five podocopid ostracods are described from the Sizewell Member (Pre-Ludhamian Stage) of the Red Crag Formation and new information regarding their phylogeny and palaeozoogeography is presented. Four of the species are new to science, Microcytherura gelida sp. nov., Thaerocythere liebaui sp. nov., Thaerocythere russus sp. nov. and Pectocythere hollowayae sp. nov., while the fifth, Neomonoceratina tsurugasakensis (Tabuki), is reexamined and reassigned. The comparative morphology of Pectocythere Hanai and Kotoracythere Ishizaki is reviewed and a morphological continuum recognized between phenotypic end-members. Pectocythere hollowayae sp. nov. forms part of a distinctive morphological group comprising Arctic and northern Pacific species: P. ishizakii Irizuki and Yamada, Pectocythere? sp. cf. P.? dentarticulata (Smith) sensu Swain and Gilby, Kotoracythere sp. Irizuki, P. janae Brouwers and P. parkerae Swain and Gilby. Although lacking a distinctive caudal process, Paijenborchella tsurugasakensis Tabuki is reassigned to Neomonoceratina sensu Zhao and Whatley. Neomonoceratina tsurugasakensis displays some minor polymorphism over an enormous geo-temporal range that extends from the early Miocene of the northwestern Pacific to the late Pliocene-early Pleistocene of the southern North Sea Basin. Despite its lack of pelagic larvae N. tsurugasakensis was capable of transoceanic dispersal, evidenced by its occurrence in the early Pliocene (c. 4.90–4.81 Ma), Oosterhout Formation, Western Netherlands Basin, alongside other pan-Arctic and North Pacific ostracod taxa. Mechanisms of dispersal remain unclear but could involve passive transport on Fucus brown algae, aided by the Transpolar Drift. Further agents of dispersion could include fish and birds. The viability of water birds as vectors of invertebrate dispersal is given further credence by the discovery of Phoebastria anglica (Lydekker), a fossil albatross, in the Pliocene crags of East Anglia.

Pliocene climate and seasonality in North Atlantic shelf seas

This paper reviews North Atlantic shelf seas palaeoclimate during the interval 4-3Ma, prior to and incorporating the 'Mid-Pliocene warm period' (ca 3.29-2.97Ma). Fossil assemblages and stable isotope data demonstrate northwards extension of subtropical faunas along the coast of the Carolinas-Virginia (Yorktown and Duplin Formations) relative to the present day, suggesting a more vigorous Florida Current, with reduced seasonality and warm water extending north of Cape Hatteras (reconstructed annual range for Virginia 12-30 degrees C). This interpretation supports conceptual models of increased meridional heat transport for the Pliocene. Sea temperatures for Florida (Lower Pinecrest Beds) were similar to or slightly cooler than (summers 25-27 degrees C) today, and were probably influenced by seasonal upwelling of cold deep water. Reduced seasonality is also apparent in the Coralline Crag Formation of the southern North Sea, with ostracods suggesting winter sea temperatures of 10 degrees C (modern 4 degrees C). However, estimates from Pliocene bivalves (3.6-16.6 degrees C) are similar to or cooler than the present day. This 'mixed' signal is problematic given warmer seas in the Carolinas-Virginia, and climate model and oceanographic data that show warmer seas in the 'Mid-Pliocene' eastern North Atlantic. This may be because the Coralline Crag Formation was deposited prior to peak Mid-Pliocene warmth.