Biostratigraphy and Facies Analysis of Upper Valanginian-Upper Hauterivian (Sarmord Formation) in Maten Anticline, Northern Iraq

Biostratigraphical and sedimentological study of the Sarmord Formation (Upper Valanginian - Upper Hauterivian) at the southern limb of Maten anticline is conducted within a well-exposed section. The formation is composed of marl, marly limestone, limestone, and dolostone, which yielded moderately diversified benthonic foraminiferal fauna, green algae, echinoderms, gastropods and some bioclast. The stratigraphic distribution of the benthonic species permits the recognition of two well-defined biozones. These are Everticyclammina kelleri Assemblage Zone, which represents the Late Valanginian age and Pseudocyclammina lituus Assemblage Zone, indicating Hauterivian age. These larger benthonic foraminiferal biozones are correlated with other zonal schemes inside and outside of Iraq, which indicates that the age of the Sarmord Formation in Maten anticline extends from Late Valanginian to Late Hauterivian age. The Sarmord Formation in the studied section is composed of limestone, dolomite, marl and conglomerate lithofacies types. Limestone lithofacies is represented by lime wackestone microfacies. According to the characteristic features of these facies, the depositional environments extend from tidal flat to shallow open marine environments.

First report of Acanthochaetetes (Porifera: Demospongiae) from the Cretaceous Khalsi Formation, Ladakh Himalaya, India

The Cretaceous chaetetid sponge Acanthochaetetes huauclillensis Sánchez-Beristain and García-Barrera is reported for the first time from the Aptian–Cenomanian Khalsi Formation, Ladakh Himalaya, India. Its low- to high-domical growth form could suggest an adaptation to either an environment with constant sedimentation rates, or to an irregular substrate. However, these growth forms also may indicate an absence of important environmental/sedimentological changes during the lifespan of the sponges. In addition, the growth form of this species suggests a calm, non-turbulent, reef-like microenvironment. Along with the other faunal assemblages, such as the rudists, corals, and the gastropod Nerinea, A. huauclillensis indicates a tropical to subtropical shallow marine carbonate platform setting. This new finding extends its stratigraphic range from the upper Hauterivian to the Aptian–Cenomanian interval in the eastern Tethyan realm.

A new elasmosaurid plesiosaurian from the Early Cretaceous of Russia marks an early attempt at neck elongation

Plesiosaurian marine reptiles evolved a wide range of body shapes during the Jurassic and Cretaceous, including long-necked forms. Many Late Cretaceous members of the clade Elasmosauridae epitomized this part of the plesiosaurian morphological spectrum by evolving extremely long necks through somitogenesis (resulting in an increase in the number of cervical centra) and differential growth (resulting in the elongation of cervical centra). However, the early evolution of elasmosaurids remains poorly understood because of a generally poor Lower Cretaceous fossil record. We describe a new elasmosaurid, Jucha squalea gen. et sp. nov., from the upper Hauterivian (Lower Cretaceous) of Ulyanovsk (European Russia), in addition to other elasmosaurid remains from the same area. Jucha squalea is one of the oldest and basalmost elasmosaurids known and lacks a series of features that otherwise characterize the group, such as the heart-shaped intercoracoid fenestra and the median pectoral bar. However, Jucha squalea marks an early attempt at cervical elongation through differential growth. The data we gathered on the shape of cervical centra among elasmosaurids suggest multiple episodes of elongation and shortening. However, the precise patterns are obscured by an unstable phylogenetic signal.

Campanellula herishtensis n. sp. (Foraminifera; Orbitolinidae?) from the upper Aptian (Lower Gargasian) of Central Iran

The new orbitolinid foraminifer Campanellula herishtensis n. sp. is described from the upper Aptian (Gargasian) of the Yazd Block, Central Iran. Campanellula herishtensis n. sp. occurs within a small interval of the Herisht section near Ardakan, displaying more or less uniform microfacies types (foraminiferal wackestones/packstones). The Iranian form differs from Campanellula capuensis De Castro (upper Hauterivian – lower Barremian of Italy, and Algeria), the only species described of the genus so far, in size and morphology (shape, apical angle). The generic assignment of the new taxon is discussed including also the genus Orbitolinopsis Henson. The suprageneric placement of Campanellula within the Orbitolinidae according to current classifications (but contrasting the original description) still remains doubtful.

Upper Hauterivian-upper Barremian Planktonic Foraminiferal Assemblages from the Arroyo Gilico Section (southern Spain)

Late Hauterivian−earliest late Barremian planktonic foraminifera from the Arroyo Gilico section (Subbetic domain, Betic Cordillera) have been investigated to correlate their distribution to ammonite zonation and calcareous nannofossil bioevents. The 72-m-thick section spans the interval between the upper Hauterivian ammonite Crioceratites binelli Subzone, Crioceratites baleraris Zone and the lowermost upper Barremian ammonite Barrancyloceras barremense Subzone, Toxancyloceras vandenheckii Zone. Planktonic foraminiferal assemblages are rich and relatively diverse. At the base of the section in the C. binelli Subzone, as already known, Hedbergella sigali, H. infracretacea, H. daminiae, and Lilliputianella semielongata are recorded. New findings include common Hedbergella praetrocoidea and H. aptiana along with rare specimens resembling H. excelsa based on their long and elevated spire. Early appearances of taxa continue up-section with the lowest occurrences (LOs) of H. ventriosa, then Lilliputianella eocretacea in the overlying Crioceratites krenkeli Subzone, followed by H. gorbachikae, while the LO of the ‘clavate’ Lilliputianella pauliani occurs just before the end of the Hauterivian within the topmost Pseudothurmannia picteti Subzone. The lower Barremian is punctuated by a number of successive appearances, including the typical Globigerinelloides blowi recorded in the upper lower Barremian Kotetishvilia compressissima Zone. The acme of the ‘clavate’ morphotypes occurs in the Moutoniceras moutonianum Zone across the Mid-Barremian Event (MBE); besides common L. semielongata, the taxa consistently present are L. pauliani with both typical and transitional morphologies, L. eocretacea, and to a minor extent “Globigerinelloides” sigali.