Dumortieria striatulocostata Ammonite Fossil Toarcian Jurassic Germany Rare Find | Levesquei Subzone Aalen Specimen

Description

Rare Genuine Dumortieria Ammonite Fossil

This carefully selected fossil is a genuine and uncommon Dumortieria striatulocostata ammonite from Hammerstadt near Aalen in Baden-Württemberg, Germany. It is recorded from the Levesquei Subzone of the Toarcian stage, the final part of the Lower Jurassic. The photographs show the actual specimen you will receive, including its natural shape, colour, preservation, matrix and visible fossil detail. Please use the sizing shown in the photographs for full dimensions and scale.

Toarcian Lower Jurassic Geology

The Toarcian Age spans approximately 182 to 174 million years ago and closes the Early Jurassic Epoch. During this interval, much of central Europe lay beneath marine waters connected to the developing Tethys Ocean. Mud, carbonate sediment and other material accumulated on the seabed, sometimes burying ammonite shells quickly enough for them to enter the fossil record. Later compaction, mineralisation and geological uplift transformed these sediments into rock and ultimately exposed them at collecting localities.

Ammonites are among the most important fossils for dating Jurassic marine strata. Their lineages evolved rapidly and individual species had comparatively restricted time ranges, while ocean currents allowed populations to spread across broad areas. This combination enables palaeontologists to use ammonite assemblages as biostratigraphic markers and compare rock layers between distant regions.

Dumortieria striatulocostata

Dumortieria is an extinct genus within the order Ammonitida. Ammonites were marine cephalopods related to living squid, octopus and nautilus. Their shells grew as a coil divided internally into chambers. The animal occupied the outer body chamber, while sealed older chambers helped control buoyancy. Identification of Dumortieria species considers whorl shape, the degree of coiling, umbilical width and shell ornament such as ribbing.

The species name striatulocostata refers to its characteristic ornament, and specimens are assessed by comparing the preserved rib pattern and shell proportions with established material. Fossil preservation is naturally variable. Shell material may remain, be mineral-replaced, or survive as an impression or internal mould after sediment filled the shell. Matrix, worn surfaces, small fractures and irregular edges record the specimen’s geological history and are not manufactured defects.

Levesquei Subzone

The Levesquei Subzone is a refined biostratigraphic division within the Upper Toarcian. Subzones allow geologists to describe narrower intervals of time than a stage alone. A fossil assigned to this subzone therefore carries useful locality and age information, adding scientific interest beyond its visual appeal. Dumortieria ammonites are particularly associated with late Toarcian successions and help characterise this closing phase of Early Jurassic ammonite evolution.

Hammerstadt near Aalen

Aalen and the surrounding region of Baden-Württemberg are internationally known for Jurassic geology. Indeed, the Aalenian Stage of the Middle Jurassic takes its name from Aalen, although this specimen comes from the older Toarcian interval. Fossils from the area document changing marine environments through the transition from the Early to Middle Jurassic. Hammerstadt material provides collectors with a direct geological connection to this historically important German region.

Actual Specimen and Authenticity

You will receive the exact fossil shown in the photographs. Its rare species identification, Levesquei Subzone attribution and German locality make it suitable for a specialist ammonite collection, geological study, educational display or distinctive natural-history gift. It is supplied with a generic Certificate of Authenticity card carrying a lifetime guarantee of authenticity.

Handle the fossil carefully and avoid soaking, harsh cleaning products, excessive humidity or sudden temperature changes. Support it securely during display so natural edges, matrix and any exposed shell ornament remain protected.