Description
Genuine Kotetishvillia compressissima Ammonite Fossil
This carefully chosen fossil is a genuine Kotetishvillia compressissima ammonite from the Alpes-Maritimes department of south-eastern France. Dating from the Lower Barremian Stage of the Lower Cretaceous, it represents an extinct marine cephalopod that inhabited the ancient Tethyan seas more than 120 million years ago.
The specimen is particularly interesting because Kotetishvillia compressissima is an important Barremian ammonite used in the detailed biostratigraphic classification of Lower Cretaceous marine rocks. Its identifiable species, classic French Alpine provenance and recognised geological interval make it an appealing addition to a fossil collection, educational display or specialist ammonite cabinet.
The photograph shows the actual fossil specimen you will receive. Its individual coiling, ribbing, preservation, colour, matrix and natural geological features can therefore be examined before purchase. Full sizing and proportions are shown in the accompanying photograph.
This authentic fossil includes a generic Certificate of Authenticity card with a lifetime guarantee.
Fossil Classification and Geological Details
Scientific name: Kotetishvillia compressissima
Fossil type: Ammonite
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida
Suborder: Ammonitina
Superfamily: Desmoceratoidea
Geological period: Cretaceous
Epoch: Early Cretaceous
Stage: Lower Barremian
Biozone: Kotetishvillia compressissima Zone
Locality: Alpes-Maritimes, France
The species name compressissima refers to the characteristically compressed shell form associated with this ammonite. Kotetishvillia is part of an important group of Barremian ammonites recognised from the Mediterranean or Tethyan palaeogeographical province.
Ammonites are especially valuable to palaeontologists because their shell forms evolved rapidly and many species were distributed across broad marine areas. Distinctive species can consequently be used to identify the relative ages of sedimentary rocks and correlate fossil-bearing layers between different regions.
Distinctive Compressed Shell Morphology
Kotetishvillia compressissima possessed a planispirally coiled shell in which the whorls grew around a central umbilicus. The shell is characteristically compressed from side to side, producing relatively narrow whorls compared with more inflated or globose ammonite forms.
Successive whorls partly overlap the earlier growth, creating a moderately involute profile. The flanks may appear flattened or gently convex, while the outer edge of the shell, known as the venter, is comparatively narrow. This compressed architecture gives the species its recognisable streamlined appearance.
The shell ornamentation may include ribs, growth lines and periodic constrictions crossing the flanks. Constrictions represent pauses or changes in shell growth and can form pronounced grooves that continue towards the venter. The exact visibility and strength of these features depend upon the ammonite’s growth stage and the preservation of the individual specimen.
Any areas of natural wear, attached matrix, mineral deposits, fractures or incomplete shell are authentic geological characteristics. They record the fossil’s long history of burial, mineral alteration and eventual exposure.
Lower Barremian Compressissima Zone
The Barremian is a stage of the Lower Cretaceous, positioned between the Hauterivian and Aptian stages. It records an important interval in the development of Cretaceous marine ecosystems and is divided into Lower and Upper Barremian substages.
The Kotetishvillia compressissima Zone is a recognised ammonite biozone within the Lower Barremian succession of the Tethyan region. It lies above ammonite intervals associated with species such as Nicklesia pulchella and below younger Barremian zones.
A biozone is a body of sedimentary rock characterised by the presence of a particular fossil species or assemblage. Because ammonites changed rapidly through geological time, their fossils enable palaeontologists to divide extensive rock sequences into comparatively precise intervals.
The association of this species with the Compressissima Zone therefore gives the fossil more detailed geological significance than a general Lower Cretaceous age alone. It represents a recognisable chapter within the evolutionary succession of Early Cretaceous ammonites.
Cretaceous Geology of the Alpes-Maritimes
The Alpes-Maritimes region of south-eastern France contains extensive exposures of Mesozoic marine sedimentary rocks. During the Barremian, this area lay beneath part of the western Tethys Ocean, far removed from the mountainous landscape visible there today.
Fine carbonate mud, clay and the remains of marine organisms accumulated on the seabed. These sediments were gradually compacted and cemented into limestone and marl. Later tectonic movements associated with the formation of the Alps uplifted and deformed the ancient seabed deposits, eventually exposing them at the surface.
The Barremian marine environments of south-eastern France supported ammonites alongside belemnites, nautiloids, bivalves, gastropods, brachiopods, echinoids and other invertebrates. Fish and marine reptiles occupied higher levels within the food web.
Many fossil-bearing deposits in the region represent relatively open marine conditions. Their ammonite faunas have played an important role in developing the detailed biostratigraphic framework used to compare Lower Cretaceous rocks across the Mediterranean region.
Life in the Early Cretaceous Sea
Ammonites were extinct marine molluscs related to modern squid, cuttlefish and octopuses. The living animal occupied the final and largest section of its shell, called the body chamber.
The older coiled portion was divided into a sequence of chambers by curved internal walls known as septa. A narrow tube called the siphuncle connected these chambers and allowed the ammonite to regulate the proportions of liquid and gas within them. This chambered construction provided buoyancy control and helped the animal maintain its position within the water column.
Movement was achieved through jet propulsion. Water was drawn into the mantle cavity and expelled through a muscular funnel, pushing the animal in the opposite direction. A crown of tentacles around the mouth was probably used to capture small prey and explore the surrounding environment.
As the ammonite matured, new calcium carbonate shell material was added around the aperture. Additional chambers formed behind the animal as it moved forwards into an enlarged living chamber, creating the spiral growth pattern preserved in the fossil.
Natural Fossilisation and Preservation
After death, the ammonite shell descended to the Barremian seabed. The soft tissues decayed while sediment entered and accumulated around the shell. Continued burial helped protect the remains from currents, scavengers and complete physical destruction.
Over millions of years, mineral-rich groundwater altered the shell and surrounding sediment. The original aragonitic shell material could recrystallise, dissolve or be replaced by other minerals. Sediment filling the shell hardened into an internal mould capable of preserving the coiling, constrictions and other morphological details.
This Kotetishvillia compressissima ammonite is suitable for fossil collectors, Cretaceous enthusiasts, geology students and natural-history displays. The photograph shows the exact carefully selected specimen you will receive. Full sizing is shown in the photo. A generic Certificate of Authenticity card with a lifetime guarantee is included.
Reviews
There are no reviews yet.