Description
Genuine Astieriptychites stubendorffi Ammonite Fossil
This genuine fossil ammonite is identified as Astieriptychites stubendorffi and originates from the Pachsa Peninsula in Siberia. It dates from the Valanginian Stage of the Lower Cretaceous, making it an impressive remnant of a cold-water marine ecosystem that existed more than 130 million years ago.
Fossils of this type are particularly interesting because they represent the distinctive Boreal ammonite faunas that inhabited the high-latitude seas of northern Eurasia. Rather than being a replica, cast or artificial reproduction, this is an authentic geological specimen preserved through natural burial and mineralisation.
The listing photographs show the exact fossil you will receive. It has been individually selected for its identifiable ammonite form, scientific interest and Siberian provenance. Full sizing and scale information can be viewed in the photographs.
Species and Scientific Classification
Astieriptychites stubendorffi was an extinct marine cephalopod belonging to the ammonite order Ammonitida. The genus Astieriptychites is commonly placed within the polyptychitid ammonites, an important group that became especially characteristic of Boreal marine environments during the Early Cretaceous.
Its broad scientific classification includes:
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida
Superfamily: Perisphinctoidea
Family: Polyptychitidae
Genus: Astieriptychites
Species: Astieriptychites stubendorffi
Some scientific classifications treat Astieriptychites as a distinct genus, while others have historically placed it within Polyptychites as a subgenus. This reflects the close morphological relationship between these strongly ornamented Lower Cretaceous ammonites.
Ammonite Shell and Morphological Features
Ammonites in the polyptychitid group generally possessed planispirally coiled shells, with all whorls growing within approximately the same plane. Their shell ornamentation commonly consisted of pronounced primary ribs arising near the umbilical edge, which then divided into multiple secondary ribs across the flanks.
The name Polyptychitidae refers to this characteristic branching or folded rib pattern. Depending on the specimen’s growth stage and preservation, the ribs may appear strong and widely spaced on the inner flank before splitting into finer branches towards the venter, the outermost edge of the shell.
The shell would originally have been divided internally by curved partitions called septa. These created a series of chambers connected by a narrow tube known as the siphuncle. The living ammonite occupied the final and largest body chamber, while the earlier chambers helped regulate buoyancy.
Where visible, the complex junctions between the septa and the outer shell wall form suture lines. Rib structure, whorl proportions, umbilical width and suture patterns are all features used by palaeontologists when distinguishing ammonite genera and species.
Lower Cretaceous Valanginian Age
This fossil comes from the Valanginian Stage, an early division of the Lower Cretaceous Period. The Valanginian extended from approximately 139.8 to 132.6 million years ago and followed the Berriasian Stage.
During this interval, large areas of northern Siberia were periodically covered by a Boreal sea. These northern waters supported specialised ammonite communities that differed from those living in the warmer Tethyan seas farther south. Polyptychitid ammonites such as Astieriptychites became important elements of these high-latitude marine faunas.
Because ammonites evolved relatively rapidly and different species appeared during restricted intervals of geological time, they are valuable index fossils. Their remains allow geologists to identify, date and correlate marine sedimentary rocks between widely separated regions.
The presence of Astieriptychites stubendorffi provides valuable evidence for the age and Boreal character of the beds in which the specimen was preserved.
Boreal Marine Environment of Siberia
During the Valanginian, Siberia occupied a northern palaeogeographical position and experienced a marine environment very different from the region’s modern landscape. Shallow epicontinental seas extended across parts of the Siberian landmass and connected with wider Arctic marine basins.
Fine mud, silt and organic material accumulated on the seabed, forming sedimentary layers capable of preserving shells and other remains. The surrounding ecosystem would have included ammonites, belemnites, bivalves, gastropods, foraminifera and other marine organisms adapted to Boreal conditions.
The shell of this ammonite would have settled onto the seabed after the animal died. Burial beneath sediment protected parts of it from erosion and scavenging. Over immense spans of time, the sediment compacted into rock and mineral-rich groundwater altered or replaced the original shell material.
The resulting fossil may preserve an internal mould, external shell ornament or a combination of both. Natural fractures, matrix, mineral deposits, weathered areas and differences in colour are expected features of a genuine specimen and form part of its geological history.
Pachsa Peninsula Provenance
The Pachsa Peninsula locality lies within the extensive fossil-bearing regions of northern Siberia. Lower Cretaceous sections in this part of the Boreal Realm are scientifically important for their successions of ammonites, microfossils and marine sedimentary rocks.
Siberian ammonites are particularly valued by specialist collectors because they document evolutionary lineages associated with ancient Arctic and sub-Arctic seas. Their distinctive ornamentation and remote geographical origin make them notable additions to collections focused on Lower Cretaceous palaeontology, Boreal faunas or international ammonite localities.
A fossil with recorded species, geological stage and locality information provides substantially greater scientific context than an unprovenanced decorative ammonite.
Actual Specimen and Certificate of Authenticity
This carefully chosen Astieriptychites stubendorffi is the exact specimen shown in the listing photographs. The images allow you to inspect its natural shape, preservation, ribbing, colour, surrounding matrix and individual geological characteristics before purchasing.
Full sizing is shown in the photographs.
The fossil includes a generic Certificate of Authenticity card carrying a lifetime guarantee. Its combination of authentic Siberian provenance, Valanginian age, recognisable polyptychitid morphology and Lower Cretaceous geological significance makes it an excellent specimen for a fossil collection, natural-history cabinet, educational display or specialist ammonite collection.
Reviews
There are no reviews yet.