Description
Sonninia (Papilliceras) arenata Ammonite Fossil – Inferior Oolite Group, Bajocian, Dorset
This genuine Sonninia (Papilliceras) arenata ammonite fossil is a collectable Middle Jurassic marine cephalopod specimen from the Inferior Oolite Group at Milborne Wick, Dorset, UK. Dating from the Bajocian Stage of the Middle Jurassic, specifically the Sauzei Zone, this fossil is approximately 170 million years old and represents an ancient ammonite from the warm shallow seas that once covered southern Britain.
This fossil is a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card. It has been carefully chosen as an individual fossil specimen, with a photo that shows the actual piece you will receive. Full sizing please see photo.
Geology and Geological Age
Sonninia (Papilliceras) arenata comes from the Inferior Oolite Group, a classic Middle Jurassic rock unit of southern England. The Inferior Oolite is well known for its fossil-rich limestones, oolitic sediments, shell beds and important ammonite faunas. These rocks were deposited during the Bajocian Stage, when Britain was positioned much further south than today and was covered by warm, shallow, tropical to subtropical seas.
The term “oolite” refers to small rounded carbonate grains called ooids, which formed in shallow, agitated marine water. These grains accumulated with shell fragments, carbonate mud and the remains of marine organisms, later hardening into limestone. Fossils from the Inferior Oolite Group commonly include ammonites, belemnites, bivalves, brachiopods, gastropods, echinoids, corals and other marine invertebrates.
Fossil Type and Species
This specimen belongs to Sonninia (Papilliceras) arenata, a Middle Jurassic ammonite associated with Bajocian marine deposits. Sonninia is a recognised Jurassic ammonite genus within the order Ammonitida and is generally placed within the family Sonniniidae. The subgenus Papilliceras is known for distinctive shell characters within the broader Sonninia group.
Ammonites were extinct marine cephalopods related to modern squid, octopus and cuttlefish. Unlike their living relatives, ammonites possessed an external coiled shell divided internally into chambers. The living animal occupied the outer body chamber, while the earlier internal chambers helped regulate buoyancy. This allowed ammonites to move through the water column in search of food and suitable marine habitats.
Sauzei Zone Stratigraphic Interest
This fossil is from the Bajocian Sauzei Zone, an important ammonite biozone used in Middle Jurassic stratigraphy. Ammonite zones are especially valuable because ammonites evolved rapidly and had distinctive shell forms, allowing geologists to date and correlate marine rock layers with precision.
A specimen with a named species, formation, locality and biozone carries strong geological value for collectors. The Sauzei Zone places this ammonite within a well-recognised part of the Bajocian succession, adding scientific interest beyond its display appeal.
Morphology and Collectable Features
Sonninia (Papilliceras) arenata displays the classic appeal of a Jurassic ammonite, with a naturally coiled shell form and attractive palaeontological character. Depending on preservation and growth stage, specimens may show visible whorls, ribbing, shell curvature, chamber structure, natural matrix contact, mineral replacement or sutural detail.
The ribbing and shell ornament were part of the original shell structure and may have helped strengthen the shell. These features are also important for identification, as ammonite shell shape, rib style, whorl profile and suture pattern can help distinguish different genera and species. In well-preserved examples, sutures may appear as intricate lines marking where the internal chamber walls met the outer shell.
This specimen is especially desirable for collectors interested in British Jurassic fossils, Dorset ammonites, Inferior Oolite specimens, Sauzei Zone fossils and Middle Jurassic marine life.
Milborne Wick, Dorset Fossil Locality
Milborne Wick in Dorset is part of a region strongly associated with classic Jurassic fossil-bearing strata. The surrounding geology preserves evidence of shallow marine environments that existed during the Bajocian, when ammonites were abundant and diverse across the seas of Europe.
Dorset is internationally valued for its Jurassic fossils, and specimens from named localities such as Milborne Wick are sought after by collectors because they combine visual appeal with clear geological provenance. A Sonninia (Papilliceras) arenata ammonite from this locality is suitable for fossil collections, educational displays, geology study sets, cabinet display and natural history collections.
Depositional Environment
This ammonite was preserved in sediments laid down beneath a warm Middle Jurassic sea. The environment likely included shallow carbonate waters, oolitic shoals, shell banks and sea floors rich in marine life. After the ammonite died, its shell settled into the sediment and became buried among carbonate grains, shell debris and fine marine material.
Over millions of years, burial, compaction and mineral-rich groundwater transformed the remains into a fossil. The resulting specimen is a natural record of marine life from Bajocian Dorset, when ammonites were highly successful animals in the Jurassic seas.
Authenticity and Display
This is a genuine Sonninia (Papilliceras) arenata ammonite fossil from the Inferior Oolite Group, Middle Jurassic, Bajocian, Sauzei Zone of Milborne Wick, Dorset, UK. It includes a Certificate of Authenticity lifetime guarantee generic card and is suitable for fossil collectors, geology enthusiasts, educational collections, natural history displays, cabinet display or as a distinctive gift for anyone interested in prehistoric marine life.
The fossil has been carefully selected, and the photo shows the actual specimen you will receive. Full sizing please see photo.
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