The early Aptian transgression event in the United Kingdom

In the United Kingdom the base of the Aptian transgression is located at the base of the Perna Beds (on the Isle of Wight), although recent work on the magnetostratigraphy has indicated that this dating may be in error. Micropalaeontological work on the Isle of Wight sections has shown that the Perna Beds represent a complex event at the transition from a non‐marine to a marine succession. Foraminiferal and palynological data agree on this transition, although no biostratigraphically diagnostic taxa are present. The base of the Aptian is tentatively moved downwards to the level of the Barnes, High Sandstone Member (Vectis Formation). If correct, this realignment of the boundary would necessitate a revision of many stratigraphic ranges and diversity calculations.     

New genus of leaf-mimicking katydids (Orthoptera: Tettigoniidae) from the Late Eocene–Early Oligocene of France and England

A new leaf-mimicking katydid (Orthoptera: Tettigoniidae: Pseudophyllinae), Archepseudophylla fossilis gen. et sp. nov. is described based on tegmina from the Early Oligocene of France. Lithymnetes laurenti Théobald, 1937 from the Late Eocene of France is transferred to Archepseudophylla comb. nov. The enigmatic ‘Poekilloptera’ melanospila Cockerell, 1921 from the Early Oligocene of the Isle of Wight (UK) is transferred to Archepseudophylla comb. nov. The present discoveries in the Palaeogene of the Isle of Wight, Céreste, and Marseilles Basins represent the first fossil records of Pseudophyllinae. In addition, these records support warm and humid forest conditions near the palaeolakes of the Isle of Wight, Camoins-les-Bains, and Céreste.     

First British Mesozoic Spider, From Cretaceous Amber Of The Isle Of Wight, Southern England

Cretamygale chasei , a new genus and species of spider, is described from a single specimen preserved in amber of early Barremian age from the Isle of Wight. This is the oldest (and second Cretaceous) amber spider to be described, and the first record of a Mesozoic spider from Britain. It belongs to the group Bipectina of the infraorder Mygalomorphae, and is tentatively referred to the family Nemesiidae. It is the oldest bipectinate, extending the record by around 90 myr, the only known fossil nemesiid, and the second oldest fossil mygalomorph.     

The occurrence of Fosliella limitata (Foslie) Ganesan (a new British record) and F. lejolisii (Rosanoff) Howe (Rhodophyta,Corallinaceae) on the Isle of Wight

The occurrence of Fosliella limitata and F. lejolisii at Bembridge, Isle of Wight is reported. F. limitata is newly recorded for Britain whilst F. lejolisii has been found only rarely since disease struck Zostera in the early 1930s. The two epiphytes both grow on Zostera; F. limitata also grows on large brown and red algae. Their vegetative and reproductive structures are described and illustrated and information given regarding their seasonal occurrence from May 1975 to April 1976. Previous records of both species are discussed and a table is given summarizing the differences between the species.     

Palaeofloristic assemblages and palaeoecology of the Lower Oligocene Bembridge Marls, Hamstead Ledge, Isle of Wight

A sequence of nine, plant-macrofossil-bearing horizons has been recognized in the Lower Oligocene from the Isle of Wight, England. The plant fossils are contained in finely laminated, olive-brown to black silty-clays and clays. Some horizons exhibit rhythmic alternation of sediment couplets; others show evidence of bioturbation and rootlet penetration. These horizons are included within a sequence of finely laminated greenish grey silty-clays and clays, largely devoid of plant macrofossil material. The plant-bearing horizons contain abundant fruits, seeds, fern sporangia, Azolla megaspores, and rare leaves. The nearest living relatives of the fossils all inhabit an aquatic or marginal aquatic environment. The associated fossil fauna includes lake bottom and lake margin species. The palynoflora of the plant-bearing and immediately underlying horizons includes large numbers of planktonic algae and limited representatives of a forest vegetation. It shows a strong relationship between the occurrences of Sparganiaceaepollenites pollen and of Typha macrofossils. Palaeoecological interpretations of this plant-fossil-bearing sequence are discussed with particular reference to modern environments.
One new genus and three new species are described. Emendations are presented for four other species. Stratiotes leaf margin teeth are described.     

A SPALACOLESTINE SPALACOTHERIID (MAMMALIA,TRECHNOTHERIA) FROM THE EARLY CRETACEOUS (BARREMIAN) OF SOUTHERN ENGLAND AND ITS BEARING ON SPALACOTHERIID EVOLUTION

Abstract: Bulk screening of Early Cretaceous (Barremian) Wealden Group strata of the Wessex Formation exposed on the south‐west and south‐east coasts of the Isle of Wight, southern England, has resulted in the recovery of fragmentary remains pertaining to a new spalacolestine spalacotheriid mammal, Yaverlestes gassoni gen. et sp. nov. These represent the first European record of the Spalacolestinae. The remains comprise a dentulous incomplete dentary and isolated upper and lower molariforms, the former representing the most substantial mammal remains yet recovered from the Wealden Group. Hitherto, six species of spalacotheriid mammal were known from the Lower Cretaceous of Europe. All are referred to the genus Spalacotherium but in the case of taxa diagnosed on the basis of isolated lower teeth and other specimens where the post‐canine dentition is incompletely known, it is now evident that these referrals should be treated with caution. Furthermore, the new Wessex Formation spalacotheriid and recently described spalacotheriids from the ?Barremian of Japan, and the Barremian and Aptian of China exhibit combinations of characters that suggest that spalacotheriids were more diverse and that their evolution was more complex than previously recognized. The systematic position of an isolated tooth from the basal Cretaceous Lourinhã Formation of Portugal is discussed and the tooth reassigned to the Spalacotheriidae. Together with the new Wessex Formation taxon, eight species are now known from the Lower Cretaceous of Europe. The discovery of a spalacolestine in the Barremian Wessex Formation supports the concept of faunal interchange between Europe, Asia and North America during the Early Cretaceous. It also supports derivation of North American spalacotheriids from a European or Eurasian ancestor.     

A New Small-Bodied Azhdarchoid Pterosaur from the Lower Cretaceous of England and Its Implications for Pterosaur Anatomy,Diversity and Phylogeny

Background

Pterosaurs have been known from the Cretaceous sediments of the Isle of Wight (southern England, United Kingdom) since 1870. We describe the three-dimensional pelvic girdle and associated vertebrae of a small near-adult pterodactyloid from the Atherfield Clay Formation (lower Aptian, Lower Cretaceous). Despite acknowledged variation in the pterosaur pelvis, previous studies have not adequately sampled or incorporated pelvic characters into phylogenetic analyses.

Methodology/Principal Findings

The new specimen represents the new taxon Vectidraco daisymorrisae gen. et sp. nov., diagnosed by the presence of a concavity posterodorsal to the acetabulum and the form of its postacetabular process on the ilium. Several characters suggest that Vectidraco belongs to Azhdarchoidea. We constructed a pelvis-only phylogenetic analysis to test whether the pterosaur pelvis carries a useful phylogenetic signal. Resolution in recovered trees was poor, but they approximately matched trees recovered from analyses of total evidence. We also added Vectidraco and our pelvic characters to an existing total-evidence matrix for pterosaurs. Both analyses recovered Vectidraco within Azhdarchoidea.

Conclusions/Significance

The Lower Cretaceous strata of western Europe have yielded members of several pterosaur lineages, but Aptian pterosaurs from western Europe are rare. With a pelvis length of 40 mm, the new animal would have had a total length of c. 350 mm, and a wingspan of c. 750 mm. Barremian and Aptian pterodactyloids from western Europe show that small-bodied azhdarchoids lived alongside ornithocheirids and istiodactylids. This assemblage is similar in terms of which lineages are represented to the coeval beds of Liaoning, China; however, the number of species and specimens present at Liaoning is much higher. While the general phylogenetic composition of western European and Chinese communities appear to have been approximately similar, the differences may be due to different palaeoenvironmental and depositional settings. The western Europe pterodactyloid record may therefore be artificially low in diversity due to preservational factors.     

Shape variation in the rough periwinkle Littorina saxatilis on the west and south coasts of Britain

Variation in the shape of the shell in Littorina saxatilis Olivi has been shown to be due largely to the same variables on both the west and the south coasts of Britain, and it exhibits various clines. Two important aspects are the size of the aperture, which becomes relatively larger from the Isle of Man southwards to Cornwall and eastwards from Devon to the Isle of Wight, and the jugosity of the shell, which increases with distance from Cornwall both northwards as far as the Isle of Man and eastwards as far as Kent. Superimposed on the clines are domains of shape, notably one in Lewis/Harris, where the shells have a relatively large aperture, which is long and narrow, coupled with a rather globose second whorl. The local and geographical aspects of shell shape variation are discussed.     

Middle Aptian biostratigraphy and ammonoids of the Northern Caucasus and Transcaspia

The Middle Aptian deposits of the central and eastern regions of the Northern Caucasus and Transcaspia (Turkmenistan) are described and discussed, including the history of their studies, lithology, and characterization of ammonite zones in each region. Ammonites of the superfamilies Parahoplitoidea and Douvilleiceratoidea, which form the basis for the Middle Aptian stratigraphic framework, are discussed and their origin and taxonomic composition are briefly considered. Forty species of 12 genera and 5 families are described. The historical stratotype section of the Gargasian stage of the French Lower Cretaceous scale is discussed, including the history of its recognition and subsequent study, and its present state. The authors’ concept of the tripartite subdivision of the Aptian Stage in the Russian Scale is substantiated. The Middle Aptian deposits are described in detail, and the range and zonal subdivision of the Middle Aptian France, Great Britain, Germany, and other regions of the world are discussed. The correlation of the Middle Aptian in the Boreal and Tethyan realms is given.     

The effect of environmental change on early Aptian ostracods faunas in the Wessex Basin,southern England

A major phase of transgression in the Wessex Basin (southern England) during the earliest Aptian resulted in the collapse of the generally fresh water Barremian environment and the initiation of the marine milieu.Cypridea-rich faunas in the Shepherd's Chine Member (Vectis Formation), were gradually replaced by faunas dominated by Sternbergella cornigera, Mantelliana mantelli and Theriosynoecum fittoni. This change is interpreted as indicating that salinities had passed from fresh-oligohaline to meso- and pliohaline and that ephemeral water bodies were replaced by more widespread, permanent, lagoonal waters. The ostracods from the highest part of the Vectis Formation appear to be heralding the major transgression that was about to engulf the Wessex Basin.The marine incursion during the obsoletus Ammonite Subzone brought with it newly formed environmental niches that were rapidly occupied by microfaunas. Several ostracod species are interpreted as euryhaline, but others appear to have been restricted to marine or near marine salinities. The earliest marine ostracod faunas were recorded from the Perna Bed Member, Isle of Wight, and include abundant Asciocythere albae and frequent to common Schuleridea derooi, Neocythere gottisi, N. bordeti and Cytherelloidea sp. Other species include rare Cythereis geometrica, C. semiaperta, Eocytheropteron stchepinskyi and Protocythere croutesensis. In addition, elsewhere in southern England, Protocythere mertensi langi, Dolocytheridea intermedia, Paranotacythere (P.) oertlii and P. (P.) atypica occur. The relationship of this earliest Aptian population with that of the Paris Basin cannot be mistaken.     

Dinoflagellate cyst biostratigraphy of the Coniacian–Santonian (Upper Cretaceous): New data from the English Chalk

Results are presented here for the first chalk-based, high-resolution quantitative study of organic-walled dinoflagellate cysts (dinocysts) from the entire Coniacian–Santonian Chalk successions in east Kent and on the Isle of Wight. The lithostratigraphy and dinocyst records (137 taxa) of seven sections are presented, and the stratigraphic ranges of taxa are constrained relative to stage and zonal boundaries, located using extensive macrofossil data. Results are integrated with a previous complementary study of the Isle of Wight Santonian to test and refine existing dinocyst bioevent schemes. Sixteen dinocyst events are proposed as a sequence of biostratigraphic datum levels for the lower Coniacian to uppermost Santonian which, based on average sedimentation rates, represent an average temporal resolution of around 360 kyr. The event stratigraphy forms a basis for the first high-resolution correlation study of quantitative dinocyst data from the Upper Cretaceous of NW Europe. A new genus Culversphaera Prince, Jarvis, Pearce et Tocher gen. nov. is proposed with the new combination Culversphaera velata Prince, Jarvis, Pearce et Tocher gen. et comb. nov. Five new species: Ellipsodinium membraniferum Prince, Jarvis, Pearce et Tocher sp. nov., Senoniasphaera macroreticulata Prince, Jarvis, Pearce et Tocher sp. nov., Senoniasphaera whitenessii Prince, Jarvis, Pearce et Tocher sp. nov., Xenascus spinatus Prince, Jarvis, Pearce et Tocher sp. nov. and X. yunii sp. nov., and the new subspecies S. protrusa congrensa Prince, Jarvis, Pearce et Tocher subsp. nov. are described.     

Dispersed Fern Sporangia from the British Tertiary

Dispersed fern sporangia have been recovered from the BembridgeMarls of the Isle of Wight and from Bracklesham deposits ina borehole West of Poole, Dorset. These fern sporangia confirmthe presence of the family Polypodiaceae s.1. in the BritishTertiary flora. Previously records of this family have beenbased solely on vegetative material, usually fragmentary, forwhich taxonomic assignment is inevitably insecure. The sporangia,containing spores and with adherent paraphyses, are shown tobe most comparable with the Recent genus Acrostichum L. andare described as Acrostichum anglicumsp. nov. The distributionand occurrence of these sporangia suggests the extensive developmentof Acrostichum in the lacustrine environments of Bembridge times.     

Habitat requirements for the conservation of wood cricket (Nemobius sylvestris) (Orthoptera: Gryllidae) on the Isle of Wight, UK

In the UK, wood cricket (Nemobius sylvestris) is a ‘Species of Conservation Concern’, being restricted to only three areas in southern England. Little information is available on the specific habitat requirements of this species. In 2006, a field investigation within three woodlands on the Isle of Wight was undertaken to identify its habitat preferences. Factors positively influencing wood cricket presence within woodlands included the presence of a well-developed leaf litter layer, relatively low ground vegetation cover and height, low canopy cover and relatively short distances between individual populations. Regression models identified the degree of isolation and variables describing vegetation structure as the main predictors for wood cricket presence within woodland fragments. The results of this study indicate the preference of wood cricket for open wooded edges. Conservation efforts for this species should focus on continuation of regular management activities aimed at providing permanent open edge habitat within woodlands, to maintain viable populations.     

Eocene Spiders from the Isle of Wight With Preserved Respiratory Structures

A new fossil spider, Vectaraneus yulei gen. et sp. nov., from the Eocene Bembridge Marls Insect Bed of the Isle of Wight, shows internal anatomy, including book lungs and tracheae, preserved by calcium carbonate replacement. The wide, medially positioned, tracheal spiracle and large tracheae which enter the prosoma are adaptations for an amphibious mode of life. The spider is placed in Cybaeidae Simon, 1898, Argyronetinae Menge, 1869, a subfamily which includes the Recent European Water Spider, Argyroneta aquatica (Clerck, 1757). The only previously described Bembridge Marls spider, Eoatypus woodwardii McCook, 1888, is redescribed; it is unrelated to Vectaraneus . The holotype of Argyroneta antiqua Von Heyden (1859) is redescribed; it is not an Argyroneta . Specimens referred to A. antiqua by Bertkau (1878) probably belong in Argyronetinae Menge, 1869, and this subfamily is emended herein.     

A mineralogical method to determine cyclicity in the taphonomic and diagenetic history of fossilized bones

The study of authigenic minerals within the voids of a fossilized bone can reveal its diagenetic history. When the order of precipitation of minerals is plotted on an Eh/pH diagram any cyclicity in the diagenetic history is revealed. If one cycle is displayed then it can be assumed that the bone has been found in its original bed of deposition; if two cycles or more are revealed then reworking or environmental change may have taken place. This is demonstrated in a case study of two bones from the Wealden Group (Lower Cretaceous) from the Isle of Wight, UK.     

Reconstruction of a Lower Cretaceous conifer

Remains of Pseudofrenelopsis parceramosa (Fontaine) Watson (Cheirolepidiaceae) from the Wealden of the Isle of Wight have been examined from the point of view of the branching and mode of growth of the plant. Evidence is presented that the tree exhibited seasonal growth and that the young extension shoots bore numerous temporary ultimate branch? is of limited growth. The tree was probably adapted to warm seasonally arid conditions.     

A NEOSELACHIAN SHARK FROM THE NON-MARINE WESSEX FORMATION (WEALDEN GROUP: EARLY CRETACEOUS, BARREMIAN) OF THE ISLE OF WIGHT, SOUTHERN ENGLAND

Abstract:  Bulk screening of Early Cretaceous (Barremian) Wessex Formation strata exposed on the south-east coast of the Isle of Wight, southern England, has resulted in the recovery of neoselachian shark teeth referred to the scyliorhinid Palaeoscyllium . These are the first neoselachian remains from the British Wealden Group and represent the geologically oldest neoselachian yet recovered from a freshwater deposit. This is also the only known example of a non-marine occurrence of a member of the Scyliorhinidae.     

A possible case of necrotizing dermatitis in the crocodylian Diplocynodon,from the Oligocene of the Isle of Wight,United Kingdom

Here we describe a pathological osteoderm from the crocodylomorph Diplocynodon hantoniensis (Bouldnor Formation, earliest Oligocene, Isle of Wight, United Kingdom). The specimen bears a porous, erosive branching channel that distorts the surface ornamentation and periosteum over 60% of the preserved dorsal surface area. We diagnose this condition as necrotizing dermatitis: a surficial bacterial or fungal infection that can penetrate the dermal layers to affect the underlaying penosteum of osteoderms. This condition has been previously reported for an extant tortoise and caiman; however, this is the first reported occurrence in the fossil record.     

The palaeoecology of the dinosaurs of the Wessex Formation (Wealden Group, Early Cretaceous), Isle of Wight, Southern England

The Wessex Formation on the Isle of Wight yields an Early Cretaceous dinosaur fauna. Sedimentological evidence shows that this represents a mosaic of fluvial, floodplain and lacustrine environments within a relatively narrow east-west oriented valley. The vegetational cover on the alluvial plain had a savannah-or chaparral-like aspect, probably of low productivity. The relative scarcity of small aquatic vertebrates, absence of coals, abundance of oxidixed sediments and the presence of immature calcretes indicate seasonal water supply. The dinosaur taxa compising the Wessex Formation faunal assemblage represent a single palaeocommunity which inhabited the local alluvial plain, although some species may have been transient. The fauna had a relatively low diversity and this is attributed to the low productivity of the local vegetation. Iguanodontids and Hypsilophodon were the dominant elements in the fauna. In contrast to Late Jurassic dinosaur faunas, sauropods are less abundant in the Wessex Formation, although they remain taxonomically diverse. It is concluded that climatic changes which took place in the Late Jurassic or Early Cretaceous resulted in the appearance of low productivity vegetation and that this was incapable of supporting large sauropod populations.     

Two new species of Constrictoceras nov. gen. (Ammonoidea) from the Early Cretaceous (Aptian) of Hungary

The new genus Constrictoceras is described below, and is represented in Hungary by two new species: Constrictoceras foezyi sp. nov. and Constrictoceras steineri sp. nov. According to morphological similarities, they are provisionally assigned to Acanthohoplitinae, but the lack of sutures cannot keep us from the idea of a possible relationship with Puzosiinae or Silesitidae, therefore its phylogenetic position of Constrictoceras gen. nov. is uncertain. Morphologically similar forms are described from the Aptian of Madagascar (Collignon, M., 1962) and from the Middle Aptian of Colombia (Sharikadze et al., 2004). Stratigraphical and paleobiogeographical use is very limited for the new genus.