New cirripedes (Crustacea,Thoracica) from the Jurassic and Cretaceous of the United Kingdom

Extensive new material of scalpelliform cirripedes, including articulated individuals, from the Late Jurassic (Tithonian) Kimmeridge Clay of Dorset, southern England, is described and used as a basis for taxonomic revision of the family Zeugmatolepadidae. Two subfamilies, the Zeugmatolepadinae and Martillepadinae nov., are established and two new genera (Martillepas, Concinnalepas) in the latter subfamily are described from the Upper Jurassic and one (Icenilepas) from the Upper Cretaceous Chalk. Material from the Kimmeridge Clay of Dorset also includes the oldest fossil representative of the family Pollicipedidae for which a new genus and species, Etcheslepas durotrigensis, are erected, and the oldest calanticid, Cretiscalpellum sp. nov. Jurassic taxa established by T.H. Withers in 1928, on the basis of sparse material, are redescribed, and referred to the new genera as Martillepas ovalis, M. costata, M. hollisi, Concinnalepas concinna and Etcheslepas fragilis.     

The thoracican cirripede genus Concinnalepas Gale, 2014 (Crustacea) from the Middle and Upper Jurassic of southern England and northern France

New material of the cirripede genus Concinnalepas is described from the Kimmeridge Clay (Tithonian) of Dorset (UK) and the Marnes de Port (Bathonian) of Port-en-Bessin in Normandy (France). Articulated specimens of C. costata (Withers, 1928), attached to driftwood from Kimmeridge, provide hitherto unknown details of tiered lateral plate formation in the species, and Concinnalepas bessinensis sp. nov. and C. rugosa sp. nov. are described from Normandy and Dorset, respectively. Concinnalepas bessinensis sp. nov. is the oldest calcite-shelled cirripede known to date. A review of the distribution of Jurassic calcareous cirripedes demonstrates that pre-Kimmeridgian records are very sparse and scattered and the early evolutionary history of the group is poorly known. The late Kimmeridgian and Tithonian saw a radiation of the Family Zeugmatolepadidae and a great increase in abundance of cirripedes that mostly lived as epiplankton, attached to driftwood and ammonite shells.     

A truly gigantic pliosaur (Reptilia,Sauropterygia) from the Kimmeridge Clay Formation (Upper Jurassic,Kimmeridgian) of England

Four isolated cervical vertebrae from the Kimmeridge Clay Formation (Upper Jurassic, Kimmeridgian) of Abingdon, Oxfordshire, England are identified as from a pliosaurid plesiosaurian sauropterygian on account of their shortness relative to width and height, their near platycoelous nature and the location of tall rib facets on the centrum body. They are noteworthy for their size, with a maximum width of 269 mm, maximum height of 222 mm and maximum length of 103 mm. Simple scaling and comparisons with cervical vertebrae of Mid Jurassic pliosaurs Peloneustes and Liopleurodon, and the Early Cretaceous Stenorhynchosaurus and Sachicasaurus suggest a total body length of between ~ 9.8 m and 14.4 m for the Abingdon Kimmeridge Clay pliosaur. Likely the true length was towards the higher end of this range.A genus and species cannot be confidently determined on the basis of the described material, but they likely belong to Pliosaurus sp. or a similar animal, for which a precise neck length is not known. We estimate a neck length of 0.77 m for Pliosaurus ?brachyspondylus based on the average cervical lengths provided for specimen CAMSM J.35991.     

A new peculiar muensterellid coleoid (Cephalopoda) from the Kimmeridge Clay Formation of Dorset (England)

A concretion from the lower Tithonian Kimmeridge Clay Formation (Pectinatus Zone) found by Steve Etches yielded a gladius of a coleoid cephalopod. It is peculiar in shape and has an unusual ornamentation of radiating ribs and tubercles. The new form is named Etchesia martilli n. gen. n. sp. and preliminarily placed within the octobrachian family Muensterellidae based on its limpet-like gladius. Through the presence of radiating ribs as well as the absence of a narrow anterior rachis E. martilli n. gen. n. sp. is similar to Pearceiteuthis buyi from the Oxford Clay Formation (Callovian). The new muensterellid is unique in having an enrolled patella apex, which is located close to the posterior gladius rim. E. martilli n. gen. n. sp. represents the first muensterellid coleoid from the Kimmeridge Clay Formation. A phylogenetic relationship of E. martilli n. gen. n. sp. (and Pearceiteuthis) with cirrate and incirrate octopods is discussed, although further information on soft parts such as the muscular mantle is necessary.     

Arm hooks of coleoid cephalopods from the Jurassic succession of the Wessex Basin,Southern England

The Jurassic succession of the Wessex Basin – especially that cropping out within the Dorset and East Devon Coast World Heritage Site – contains important lagerstätten for coleoid cephalopods. The Blue Lias and Charmouth Mudstone formations of West Dorset, the Oxford Clay Formation of North Wiltshire and the Kimmeridge Clay Formation of Purbeck have provided large numbers of important body fossils that inform our knowledge of coleoid palaeobiology, including the hooks present in the arms. Isolated hooks are also found in the processed residues studied by micropalaeontologists and these occurrences can be used – in some cases – to record the presence of key taxa in the absence of well-preserved body fossils. While some hook morphotypes can be attributed to known species, there are many forms of hook described where the parent animal remains unknown. The present state of our knowledge of the Jurassic assemblages in the Wessex Basin is presented and remaining issues identified.     

A new neoselachian shark from the marine Early Cretaceous of Southern England

Rare, isolated teeth of Corysodon multicristatus sp. nov. are described from two levels in the Atherfield Clay Formation (Early Aptian, Early Cretaceous) of Atherfield Point on the Isle of Wight, UK. Ten teeth of the new species were recovered from 1095 kg of washed and graded sediment residues. The teeth themselves are very small (around 0.5 mm high) and possess a distinctive crown bearing a tiered series of transverse crests adapted for rasping. Details of the dental architecture of the Atherfield Clay Formation specimens clearly indicate that the Cretaceous material differs significantly from the teeth of the type species for the genus, Corysodon cirinensis, recorded from the Kimmeridgian of northern France and Switzerland. C. multicristatus is the first substantiated record of the genus from the Early Cretaceous, thereby extending the stratigraphic range of the genus from the latest Jurassic, and the geographical range from continental Europe to the UK.     

Field meeting in the Isle of Purbeck,September 2012, to examine the Upper Kimmeridge Clay and the Lulworth district

An account is given of a Geologists’ Association meeting in the Isle of Purbeck held on 28th–30th September 2012 and the stratigraphy and structures of the rocks examined during the weekend are described. Uppermost Jurassic Stage nomenclature and recent changes to stratigraphical nomenclature in the uppermost part of the Kimmeridge Clay Formation are discussed and the conclusion reached that the long-established divisions (Members) of this Formation are both readily recognisable and have nomenclatorial priority. The recent change to the position of Pallasioides-Rotunda zonal boundary ignores the ammonite fauna and is inappropriate. For the Lulworth district the stratigraphy of the uppermost Jurassic (Portlandian) through Lower and Upper Cretaceous formations are described and their associated structures discussed. The coastal evolution of the Lulworth coast is briefly discussed.     

Thoracican cirripedes (Crustacea) from the Hauterivian (Lower Cretaceous) of Hannover,northern Germany

Diverse thoracican cirripedes from the Hauterivian of the Hannover district of northern Germany are described, including seven species, belonging to five genera. Of these, a new genus belonging to the Scalpellidae, Jaegerscalpellum, includes one Hauterivian species, J. elegans sp. nov., an Aptian species, J. comptum (Withers, 1910) and an Albian species, J. politum (Darwin, 1851) are also referred to it. A new Cretiscalpellum, C. mutterlosei sp. nov. is described from the Hauterivian, and C. matrioni sp. nov. is described from the Middle Albian of France. The oldest record of the Unilatera Gale, 2018, Pedupycnolepas pulcher sp. nov. is described from the Hauterivian; this displays typical shell structure of the group, retained by living Verrucidae. Finally, four species of Zeugmatolepadidae, subfamily Martillepadinae, are recorded from the Hauterivian, including Martillepas hausmanni (Koch and Dunker, 1836), M. decoratus sp. nov., M. auriculum sp. nov. and Etcheslaepas borealis (Collins, 1990). The Hauterivian fauna from Hannover shows affinities both with Late Jurassic and later Cretaceous (Aptian-Cenomanian) forms, and includes the earliest scalpellids, unilateran (Pedupycnolepas) and Cretiscalpellum species known. It constrains the age of the Cretaceous cirripede evolutionary radiation to the earliest Cretaceous.     

New coelacanth material from the Middle Triassic of eastern Switzerland, and comments on the taxic diversity of actinistans

New coelacanth material from the Middle Triassic Prosanto Formation of the Ducan and Landwasser area near Davos in eastern Switzerland, Canton Graubünden, is described. A sub-complete individual is visible in ventral view, and shows details of its branchial apparatus. In particular, it possesses relatively large teeth on the ceratobranchials, and possible ossified hypobranchials. Few diagnostic characters are observable, and most of them are visible on the mandibles preserved in lateral view. This specimen shares characters with Ticinepomis peyeri, a smaller form from the Middle Triassic of Monte San Giorgio, whose holotype is re-described in part here. A second specimen, a fragmentary caudal skeleton shows the typical supplementary lobe of coelacanths, and meristic characters indicating probable close affinities with T. peyeri. We refer this material to Ticinepomis cf. T. peyeri. Because the new specimen is larger than the holotype, we refute the possible juvenile status of the small specimen from Monte San Giorgio. The new material of Ticinepomis from Canton Graubünden shows anatomical features not preserved on the holotype and allows the addition of new characters to a previously published data matrix of actinistians. A phylogenetic analysis is performed, which supports that Ticinepomis is nested among the Latimeriidae. The diversity of post-Palaeozoic coelacanths is assessed. The taxic diversity of observed occurrences shows a peak in the Early Triassic and a peak in the Late Jurassic, as detected in previous studies. When ghost lineages are included in the computation, the Late Jurassic peak is smoothened. By comparing the taxic diversity curves with the curve of average ghost lineage duration, we conclude that the Early Triassic peak of diversity was probably caused by a biological radiation, whereas the Late Jurassic peak of observed diversity is probably the result of a Lagerstätten effect.     

A new afrograptid (Diplostraca: Estheriellina) from the Lower Cretaceous of southern England

The Family Afrograptidae is a ‘conchostracan’ group with multiple radial costae reaching to the umbo on their carapaces. It comprises four described genera: Afrograpta, Camerunograpta, Congestheriella and Graptoestheriella with a total of thirteen described species which are occasionally reported from the Jurassic and the Cretaceous in Africa, Europe and South America (i.e. Afrograpta from the Upper Cretaceous of Cameroon; Camerunograpta from the Jurassic to Cretaceous of Cameroon; Congestheriella from the Jurassic to Upper Cretaceous of the Congo Basin, Brazil, Bulgaria, Venezuela and Argentina; and Graptoestheriella from the Upper Jurassic to Lower Cretaceous of Brazil). A new genus and a new species, Surreyestheria ockleyensis gen. et sp. nov., belonging to the Family Afrograptidae from the Lower Cretaceous (lower Barremian) Upper Weald Clay Formation of Ockley Village, Surrey County, southern England is described in this paper. The new genus mainly differs from the other four genera by the special reticulate ornamentation on its carapace. It indicates that the Family Afrograptidae was more diverse and more widely distributed in the late Mesozoic than previously supposed. Afrograptidae is a special branch of Estheriellina the latter originating in the late Palaeozoic and the former in the early Mesozoic. Afrograptids, as a whole had been widespread across Pangea in the Early Jurassic.     

Possible animal body fossils from the Late Neoproterozoic interglacial successions in the Kimberley region, northwestern Australia

New specimens of the enigmatic Ediacara-type fossil Palaeopascichnus have been identified from the upper part of the Neoproterozoic Ranford Formation in the Kimberley region, northwest Australia. New material is morphologically similar to Palaeopascichnus and represents the largest species of this genus. They resemble the present-day xenophyophore protists in chamber morphology and growth patterns, supporting the interpretation that Palaeopascichnus is possibly a xenophyophore body fossil rather than a trace fossil. Stratigraphic correlation reveals that the new Palaeopascichnus specimens are preserved in the interglacial successions between the Landrigan/Marinoan and Egan/Ediacaran glaciations. If correlation with the early Ediacaran formations of South Australia is accepted, this represents the earliest known identifiable member of the Ediacara biota. New fossil record fills the evolutionary gap between the Cryogenian and Ediacaran animal assemblages and well-known Ediacaran biota. The new Palaeopascichnus specimens represent the first record of Ediacara-type fossils in Kimberley, and suggest the probability that additional Ediacaran fossils may be found in northwestern Australia.     

Upright crinoids of the Thornton Reef,Wenlock (Silurian) of Illinois,USA

The rare preservation of columns perpendicular to bedding may provide convincing evidence that ancient crinoids adopted an upright attitude during life. However, taphonomic and sedimentological analyses are important in determining whether such occurrences are truly in situ or represent unusual allochthonous accumulations. The Crinoid Biosome of the Thornton Reef Complex, Silurian of Illinois, USA, includes pluricolumnals preserved perpendicular to bedding, in association with more common specimens parallel or angled to bedding. Upright pluricolumnals are relatively shorter (<150 mm) than the longest non-upright specimens; they sometimes occur as imbricate accumulations and lack attachment structures (although these are preserved separately). Brachiopod valves and colonial corals may also be preserved perpendicular to bedding. These features suggest that the Thornton beds were formed as viscous mass flow deposits and that the upright crinoid columns are allochthonous or, at best, parautochthonous. © 1996 John Wiley & Sons, Ltd.     

Leptolepid otoliths from the Hauterivian (Lower Cretaceous) Lower Weald Clay (southern England)

Teleostean saccular otoliths from the upper part of the late Hauterivian Lower Weald Clay Formation of the Wealden Supergroup exposed at Langhurstwood Quarry, West Sussex, UK, and Clockhouse Brickworks, Surrey, UK are described for the first time. Two new species of the genus Leptolepis, Leptolepis wealdensis and Leptolepis toyei are described. Many of the specimens are densely packed on individual bedding planes and they are interpreted as coprocoenotic accumulations. Additional mechanisms of deposition and concentration are discussed, in particular wave action. Ontogenetic series show isometric growth of the otoliths, and some specimens show growth rings on two orders of magnitude.     

Compositions,sources and depositional environments of organic matter from the Middle Jurassic clays of Poland

The comprehensive biomarker characteristics from previously undescribed Middle Jurassic clays of Poland are presented. The molecular composition of the organic matter (OM) derived from clays of Aalenian to Callovian age has not changed significantly through time. High relative concentrations of many biomarkers typical for terrestrial material suggest a distinct dominance of OM derived from land plants. Increasing concentrations of C₂₉-diaster-13(17)-enes towards the northern part of the basin indicate an increase in terrestrial input. This terrestrial material would have originated from the enhanced transport of organic matter from land situated at the northern bank of the basin, i.e., the Fennoscandian Shield. The organic matter was deposited in an oxic to suboxic environment, as indicated by relatively low concentrations of C₃₃–C₃₅ homohopanes, moderate to high Pr/Ph ratio values, an absence of compounds characteristic for anoxia and water column stratification, such as isorenieratane, aryl isoprenoids and gammacerane, as well as common benthic fauna and burrows. δ¹⁸O measurements from calcitic rostra of belemnites suggest that the mean value of the Middle Jurassic sea-water temperature of the Polish Basin was 13.1 °C. It is suggested that this mirrored the temperature of the lower water column because belemnites are considered here to be necto-benthic. The organic matter from the Middle Jurassic basin of Poland is immature. This is clearly indicated by a large concentration of biomarkers with the biogenic configurations, such as ββ-hopanes, hop-13(18)-enes, hop-17(21)-enes, diasterenes and sterenes. The identification of preserved, unaltered biomolecules like ferruginol, 6,7-dehydroferruginol and sugiol in Protopodocarpoxylon wood samples from these sediments present particularly strong evidence for the presence of immature OM in the Middle Jurassic sediments. Moreover, the occurrence of these polar diterpenoids is important due to the fact that they are definitely the oldest known natural products detected in geological samples.     

The Late Jurassic ray Kimmerobatis etchesi gen. et sp. nov. and the Jurassic radiation of the Batoidea

The laminated marine mudstones of the Late Jurassic of Kimmeridge, southern England, yield two exceptionally well-preserved partial skeletons of a previously unrecognised species of early batoid. These are described as a new genus and species, Kimmerobatis etchesi gen. et sp. nov. which has a general “guitarfish” bauplan as in all other batoids known from the Jurassic. This species possesses a combination of primitive characters such as centra present within the majority of the synarcual and antorbital cartilages that fail to reach the pectoral skeleton along with more derived characters, such as the lack of fin spines. Until now, little study has been carried out on the affinities of Jurassic batoids, despite their key role in understanding batoid evolution. Results from parsimony and likelihood phylogenetic reconstruction indicates that the whole-bodied Jurassic batoids Spathobatis, Belemnobatis, and Kimmerobatis gen. nov. form their own clade, Spathobatidae, and do not lend support to a monophyletic “Rhinobatidae”. Among Jurassic batoids, Kimmerobatis gen. nov. is most derived, but with derived characters being independently acquired compared to modern batoids (e.g. presence of a postpelvic process). The inclusion of whole bodied Jurassic fossils have generated a more resolved hypothesis of batoid evolution throughout the Cretaceous and into the Cenozoic.     

New Fossil Palaeontinids from the Middle Jurassic of Daohugou,Inner Mongolia,China (Insecta,Hemiptera)

Two new genera and species of fossil Palaeontinidae are described from Daohugou Village, Inner Mongolia, China: Cladocossus undulatus gen. et sp. nov. and Cricocossus paradoxus gen. et sp. nov. Both new genera are described based on well-preserved forewings. This discovery confirms the high diversity of palaeontinids during the Middle Jurassic. Both specimens have interesting modal structures which are new to Palaeontinidae: M five-branched and M3 with two branches. Based on this character, wing structural characteristic is discussed.     

Asterozoan ichnofossils (Asteriacites lumbricalis von Schlotheim) from the Middle Jurassic (Aalenian) Birdlip Limestone Formation (north Cotswolds,central England)

Well preserved asterozoan ichnofossils (Asteriacites lumbricalis von Schlotheim) are documented from calcareous sandstone lenses within the upper part of the Harford Member of the Middle Jurassic (Aalenian) Birdlip Limestone Formation, in the north Cotswolds, central England. The ichnofossils are interpreted as undertraces, generated by the activity of small ophiuroids in a storm-influenced muddy coastal lagoon or bay margin setting.     

Ammonites from the Lias Group (Lower Jurassic,Sinemurian and Pliensbachian) of White Park Bay,Co. Antrim,Northern Ireland

Northern Ireland's Jurassic succession has received relatively little detailed investigation. Late Sinemurian and early Pliensbachian strata are present in parts of north Antrim but they are poorly exposed at outcrop and have been penetrated by just a single borehole, at Portmore, in which parts of the succession are missing. Collecting from White Park Bay over more than two decades, augmented by examination of museum material, has established the presence within the Rathlin (North Antrim) Basin of ammonite zones and subzones additional to those proven in the Portmore Borehole. This suggests that parts of the Sinemurian and Pliensbachian stages, from the Obtusum Zone through to the Davoei Zone, and possibly even higher, may be preserved in onshore or nearshore parts of the basin. Despite the generally poor exposure, the material recovered encompasses more than 40 ammonite species, including several taxa that are poorly represented elsewhere in the UK, of which two, Vicininodiceras dalriatense sp. nov. and Cheltonia howarthi sp. nov., are previously undescribed.