Pollen cone anatomy of Classostrobus crossii sp. nov. (Cheirolepidiaceae)

Discovery of a permineralized fossil cone in Mesozoic deposits of southern England provides an opportunity to document the first detailed evidence of internal pollen cone anatomy for the extinct conifer family Cheirolepidiaceae. The specimen, described here as Classostrobus crossii sp. nov., occurs in a calcareous nodule recovered from Middle Jurassic marine sediments of the Lower Callovian Sigaloceras calloviense biozone, Kellaways, near Cirencester, England. The cone is 2.0 cm long and 1.8 cm wide. Sporophylls diverge helically from the axis. Each sporophyll displays a narrow stalk and a distal lamina approx. 11 mm long that tapers to a pointed tip. There is also a basal keel that bends inward at the bottom and sides to form a shallow pocket. A single vascular bundle diverges from the cone axis, extends distally into the sporophyll stalk at the contact of two distinctly different histological zones, and further expands into the distal lamina as transfusion tracheids. Several pollen sacs are attached abaxially at the juncture of the sporophyll stalk and keel. Pollen is roughly spheroidal, 26–35 μm in diameter, with unequal polar caps separated by a striated belt with a subequatorial furrow. This specimen helps clarify the range of variation in the morphology of Mesozoic conifer pollen cones.     

Evidence of freshwater dinoflagellates and other algae in the English Wealden (Early Cretaceous)

The remains of phytoplankton occur at many horizons in the Wealden succession of southern England. Some of these are dinocysts that are identical to known marine Early Cretaceous species but the sedimentological and palaeontological associations of others indicate fresh-water origins. Species of the cyst genera Australisphaera, Ripea and several new forms are among the members of this group. They commonly occur together with the chlorococcalean algae Pediastrum, Scenedesmus, Tetraedron and Tetrastrum. The last of these has not had a fossil record hitherto, and both Scenedesmus and Tetraedron have hardly ever been reported previously from pre-Quaternary deposits. These findings contradict the widely held opinion that dinoflagellates did not occupy freshwater habitats until the beginning of the Cenozoic Era.     

A new family of scorpionflies (Insecta; Mecoptera) from the Lower Cretaceous of England

Seven specimens of fossil scorpionflies (Mecoptera) not assignable to any known family were discovered in the Wealden Supergroup (Lower Cretaceous) of southern England. They were found at Rudgwick Brickworks, West Sussex and Smokejacks Brickworks, Surrey and came from the Upper Weald Clay Formation, dated as Barremian (∼129.4–125 Ma). A new family – Englathaumatidae fam. nov., new genus – Englathauma gen. nov. and two new species E. crabbi sp. nov. and E. mellishae sp. nov. are described. A discussion of systematic position of these new taxa within the order Mecoptera is given. Englathaumatidae fam. nov. has been a nomen nudum since the year 2002, due to the first author's untimely death.     

A new ornithischian dinosaur and the terrestrial vertebrate fauna from a bone bed in the Wealden of Ardingly,West Sussex

The Wealden Supergroup of south-east England has long been of interest to palaeontologists because of its diverse flora and fauna. The Supergroup is Early Cretaceous in age, occupying the time period immediately after the enigmatic end-Jurassic extinction. Wealden faunas therefore have the potential to be informative about the tempo and mode of post-extinction recovery, but due to lack of exposure in this densely populated part of southern England, are difficult to sample. In the summer of 2012, a number of ex situ fossiliferous blocks of sandstone, siltstone and limestone were discovered from building excavations at Ardingly College, near Haywards Heath in West Sussex. The sedimentology of the blocks indicates that they are from the Valanginian Hastings Group, and that Ardingly College is underlain by the Grinstead Clay Formation, rather than the Ardingly Sandstone Member. The blocks contain a diverse invertebrate fauna and flora, as well as vertebrate remains, which are found in a distinct sandstone horizon that probably represents the Top Lower Tunbridge Wells pebble bed. A tooth from an ornithschian dinosaur cannot be referred to any of the ornithischian taxa known from the Wealden Supergroup, and therefore represents a new taxon. Teeth of the crocodilian Theriosuchus extend the known range of this taxon in the Wealden, while teeth of an ornithocheird pterosaur confirm the presence of these animals in the skies above the Wealden sub-basins. Fusainized plant remains and the wing-case of a cupedid beatle indicate that wildfire was a ubiquitous feature of the Weald Sub-basin during the Valanginian.     

Molecular composition and chemosystematic aspects of Cretaceous amber from the Amazonas,Araripe and Recôncavo basins,Brazil

Amber occurrences in Brazil are rare. In this regard, the molecular composition of three such fossil resin samples from Brazilian Cretaceous sedimentary basins has been analyzed to determine the botanical origin of the resins. The samples were collected from the Amazonas (Alter do Chão Formation), Araripe (Santana Formation, Crato Member) and Recôncavo (Maracangalha Formation, Caruaçu Member) basins. The mono-, sesqui- and diterpenoids in the extracts were used as chemosystematic markers when compared with terpenoids in extant conifers. The compounds were mainly diterpenoids and their degradation products from the labdane, podocarpane, pimarane and isopimarane classes, in addition to paraffins, methoxyphenols and carboxylic acids. Tetracyclic diterpenoids such as phyllocladane, kaurenol and kauranol were also present. The biomarker compositions are certainly typical for conifers and, given the absence of triterpenoids and diterpenoids such as ozic acid, angiosperms can be excluded as a botanical source. The absence of phenolic diterpenoids (ferruginol, totarol) and their derivatives excludes podocarpaceous affinities for the ambers from the Amazonas and Araripe basins. The fossil records of the embedding sediments (e.g. Araucariaceae pollen and leaves) support the proposal of an Araucariacae origin for these ambers, but Cupressaceae and Cheirolepidiaceae cannot be excluded. On the other hand, the presence of phyllocladane and kaurane derivatives is evidence for Araucariaceae or Podocarpaceae origins for the amber from the Recôncavo basin, but Cupressaceae cannot be excluded.     

欧洲白垩纪非海相软体动物及其地层分布

本文综述了欧洲白垩纪非海相软体动物群,列出了主要产自英格兰南部、法国和西班牙早白垩世的16个不同沉积层的59个分类单元。淡水动物群以珠蚌类双壳类和田螺类腹足类为主,但在有些地点也存有肺螺类腹足类。这些化石类群与现代类型很相似,说明白垩纪淡水中的水草、氧气与营养环境良好。在欧特里沃期和巴列姆期,淡水与边缘海环境中的动物群组成都发生了显著的变化。欧洲的淡水生物群落早在巴列姆期就已存在,此时的有些类群,如著名的Mar garitifera(s.l.)valdensis在欧洲西部有着广泛的分布。英格兰南部的早白垩世韦尔登群被认为是欧洲最连续的非海相白垩纪地层,其上部的生物群可与西班牙的LasHoyas动物群和法国的Wassy动物群相对比。这3个动物群,以及法国侏罗(汝拉)和英格兰南部波倍克的侏罗纪-白垩纪的过渡生物群——Purbeck动物群,是了解欧洲白垩纪淡水动物群的关键动物群。     

Consideration of the genus Ginkgoites Seward and a redescription of two species from the Lower Cretaceous of Germany

Genera used for fossil ginkgoalean leafy shoots, especially Baiera F. Braun,Ginkgoites Seward and Ginkgo L., are discussed both in their historical context and in the light of recent discoveries. Use of Ginkgoites Seward as a form- or organ-genus for fossil leaves lacking associated reproductive structures is readopted. Two species, Ginkgoitesbrauniana (Dunker) comb. nov. and Ginkgoites pluripartita (Schimper) Seward, from the Lower Cretaceous Wealden facies of Germany, are rediagnosed and neotypes selected. The occurrence of G. pluripartita in the Lower Cretaceous of western Greenland, Montana, U S A, Canada and Siberia is confirmed.     

A Wealden guide II: the Wessex Sub-basin

Part 1 of 'A Wealden guide' ( Geology Today , 2006, v.22, n.3) provided an introduction to the non-marine Early Cretaceous Wealden strata of southern England, and an account of the succession that outcrops within the Weald Sub-basin. This second article focuses on the Wealden of the Wessex Sub-basin, exposed on the Isle of Wight and Dorset coasts of southern and south-west England.     

The non-marine Lower Cretaceous Wealden strata of southern England

The non-marine Lower Cretaceous Wealden strata of the Wessex-Weald Basin (southern England) are introduced, with reference to the depositional model developed by Professor Percival Allen FRS (Allen, 1975). To demonstrate this model and the development of Wealden palaeoenvironments through time, Wealden sites have been selected for the Geological Conservation Review programme. Site selection rationale is briefly outlined.     

Percival Allen FRS (1917–2008): a personal tribute

This paper summarises the author's research association with Percival (‘Perce’) Allen FRS (1917–2008), whose wide-ranging and seminal contributions to Wealden (non-marine Lower Cretaceous) sedimentological and palaeoenvironmental interpretation spanned seven decades. The Geological Conservation Review (GCR) Special Issue on the Wealden was initiated as a collaborative research programme initiated during the late 1990s. Stemming from this, the GCR accounts are seen very much as the summation of Perce Allen's lifelong Wealden studies, as demonstrated by GCR sites throughout southern England.     

Molecular composition and chemotaxonomic aspects of Eocene amber from the Ameki Formation,Nigeria

The molecular composition of fossil resin from the Eocene Ameki Formation, southern Nigeria has been analyzed by infrared spectroscopy, pyrolysis–gas chromatography–mass spectrometry and thermochemolysis gas chromatography–mass spectrometry to determine the structural class and botanical source of the resin. The pyrolysis products were dominated by bicyclic products derived from regular labdatriene structure and lacked succinic acid indicating Class Ib type amber. The biomarker compositions in the pyrolysates are dominated by sesquiterpenoids of the cadinane and bisabolane classes that are common constituents of higher plants and labdane type diterpenoids. The exclusive presence of labdane type diterpenoids and the absence of higher plant triterpenoids strongly suggest that the amber was derived from a gymnosperm (conifer) botanical source. This observation contrasts with the angiosperm source previously suggested for the resin based on the palaeobotanical studies of the host sediments. The specific family source within the conifers could not be ascertained based on the molecular composition of the resin. However, the presence of methyl-16,17-dinor-callitrisate pointed to the Cupressaceae family although other Cupressaceae biomarker indicators were not detected in the resin.     

A re-evaluation of Ophiomorpha burrows in the Wealden Group (Lower Cretaceous) of southern England

Attribution of burrows in the Wealden Group of southern England to Ophiomorpha is rejected. The burrows are essentially cylindrical, unlined and with a meniscate fill. Any outer knobbly appearance is due to diagenetic poikilotopic cementation or to differential weathering of a mudchip-sand fill. The variable nature of meniscate fill reflects passage of the producer through the thin-bedded, alternating sand-mud sediments or along sand-mud interfaces. The burrows are assigned to Beaconites, though, since the identity of this ichnotaxon has been questioned, reference is also made to Taenidium. Two ichnoassociations are recognized: (1) a Beaconites antarcticus-Scoyenia (or Taenidium-Scoyenia) association (Weald Clay) of marginal lacustrine situation with fluvial input, and (2) a Beaconites barretti-Planolites (or Taenidium-Planolites ) association of the fluvial (lacustrine delta) of the Lee Ness Sandstone (Ashdown Formation). The Wealden burrows offer no inherent indications of palaeosalinity, and inferences made on supposed occurrences of Ophiomorpha in the Wealden Group must be reassessed. Other occurrences of Ophiomorpha in non-marine facies are questioned.     

The Wealden (non-marine Lower Cretaceous) of the Weald Sub-basin,southern England

The Wealden strata (non-marine Lower Cretaceous) of the Weald Sub-basin outcrop in the Weald district of south-east England; the Wealden type-area. The succession is made up of the mixed alluvial–lacustrine–lagoonal Hastings Beds Group below and the predominantly lacustrine–lagoonal Weald Clay Group above. Deposition was strongly influenced by tectonism amongst surrounding massifs, and the warm to hot, periodically wet Wealden climate. Geological Conservation Review sites within the Weald district are dominated by inland sites, but also include extensive coastal cliff and foreshore exposures near Hastings, East Sussex. The Wealden strata have been documented and interpreted since the earliest days of geological enquiry in Great Britain. Collectively, the selected sites demonstrate the key elements of a depositional model for the Wealden of the Weald, developed and published by Professor Percival Allen FRS (1917–2008) in these Proceedings (Allen, 1975). The sites are documented and interpreted, with special reference to research history, chronostratigraphy, structural context, palaeoenvironments, palaeobiology and palaeoclimatology. New directions for research are proposed, as applicable.     

First fossil insect from Lower Cretaceous Lebanese amber in Syria (Diptera: Ceratopogonidae)

Lebanoculicoides bloudani a new species of Ceratopogonidae from the Lower Cretaceous ambers of Syria and Lebanon is studied. The new species is characterized, described, illustrated, and compared with the other fossil taxa of the same extinct genus. A key to the species of the genus Lebanoculioides is proposed.     

A Wealden guide I: the Weald Sub-basin

The Wealden strata of southern England provide a range of evidence for Early Cretaceous non-marine environments and their inhabitants, and a climate of warm to hot, 'Mediterranean' aspect. Because of its exposure, and its range of facies, distinguishing a variety of sedimentary environments, the Wealden has long fascinated geologists intent on providing an environmental model. This article is one of two intended to give an overview of Wealden environments, providing the geological framework of these strata. In this article, the type-succession in the Weald Sub-basin of south-east England is summarized and briefly interpreted.     

Chalk and landscape of the South Downs, England

The Upper Cretaceous Chalk hills of the South Downs form the southern flank of the Wealden anticline in south-east England, with older Wealden and Purbeck sediments exposed at its core. With prominent chalk escarpments on each side of it, this major structure is up to 70 km wide, and extends eastwards for over 200 km from eastern Hampshire to the area around Boulogne-sur-Mer in Northern France, dissected by the English Channel.     

Early Cretaceous dinoflagellate cysts and chlorococcalean algae from freshwater and low salinity palynofacies in the English Wealden

A number of dinoflagellate cysts occur in Wealden deposits that are considered to have accumulated in fresh to slightly brackish water conditions. Most of the forms that have been encountered in the Weald Clay Group (Hauterivian-Barremian) of southeast England and the Wessex and Vectis Formations on the Isle of Wight are described and/or illustrated in this paper. Of these, the following are new: Australisphaera longicornis sp. nov., Cassiculosphaeridia parvula sp. nov., Microdinium? fibratum sp. nov., Kallosphaeridium? inornatum sp. nov., K.? spongiosum sp. nov., Pannosiella perforata gen. et sp. nov., Vectensia varians gen. et sp. nov., Corculodinium uniconicum gen. et sp. nov., Lobionella hirsuta gen. et sp. nov. and Spicadinium akidoton gen. et sp. nov. Commonly associated with several of the cysts are chlorococcalean algae referable to the genera Botryococcus, Tetraedron, Pediastrum, Scenedesmus and Tetrastrum. Four of these are also newly diagnosed, namely Tetraedron paraincus, Scenedesmus bifidus, Tetrastrum ciliatum and T. multifilorum.     

A tubiculous perspective: New caddisfly cases (Insecta: Trichoptera) from the Lower Cretaceous of southern England and comparison with the Chinese indusifauna

New finds reveal that cases of larval caddisflies (indusifauna) are widespread aquatic domichnia in Eurasian non-marine deposits. 16 new ichnospecies are described in 6 ichnogenera from the Wealden Supergroup (Lower Cretaceous) of southeast England, mainly from the Ashdown Formation (Valanginian), but some also from the Weald Clay Group (Hauterivian–Barremian). New ispp. are: Terrindusia valdensis isp. nov., T. anomala isp. nov.; Secrindusia sarahae isp. nov.; Conchindusia dianae isp. nov., C. elderi isp. nov., C. goodmani isp. nov.; Pelindusia duprati isp. nov.; ?Ostracindusia mixta isp. nov.; Folindusia stouti isp. nov., F. bipennis isp. nov., F. ruffordi isp. nov., F. chiasma isp. nov., F. woodhamsi isp. nov., F. boothi isp. nov., F. avancnae isp. nov., and F. whitei isp. nov. Two new forms, a variety and aberration of Conchindusia (an igen. with no modern analogue) are also recognised. The first Chinese isp. (Conchindusia sinensis isp. nov.) is described from the Yixian Formation (Aptian) and 31 morphotypes are listed from eight Lower Cretaceous Chinese formations.The aquatic palaeoenvironment and palaeoecology are discussed. The UK indusifauna is dominated by Conchindusia–Folindusia in contrast to a Terrindusia dominance in China; furthermore, the UK EPT (Ephemeroptera–Plecoptera–Trichoptera) richness is skewed towards Trichoptera. This reflects differences in the fluvio-lagoonal and fluvio-lacustrine settings, respectively.     

The southern English Wealden (non-marine Lower Cretaceous): overview of palaeoenvironments and palaeoecology

Geological Conservation Review sites representing the non-marine Lower Cretaceous Wealden strata provide field evidence for the physical and biological development of what is now southern England, between approximately 120 and 135 million years ago. Knowledge of Wealden climates, palaeogeology, landscapes, hydrology and palaeobiology is synthesized and summarised, with reference to the Weald and Wessex sub-basins.