Taxonomic classification
- Kingdom: Animalia
- Phylum: Mollusca
- Class: Cephalopoda
- Subclass: Ammonoidea
- Order: Ammonitida
- Family: Acrioceratidae (or related family within the superfamily Haploceratoidea)
- Genus: Acrioceras
Temporal range
- Acrioceras* is known from the Early Cretaceous period, specifically the Barremian stage (approximately 129–125 million years ago).
Geographic distribution
Fossils attributed to Acrioceras have been reported from sedimentary rock formations in Western Europe, notably in France and Spain. Additional occurrences have been documented in parts of the Middle East, though these records are less abundant.
Morphological characteristics
Shell – The shell is typically involute to moderately evolute, with a rounded to somewhat compressed whorl section.
Ornamentation – Ribbing is generally fine to moderate, often displaying a pattern of alternating strong and weak ribs. Some specimens show occasional tubercles or nodes on the ventrolateral area.
Umbilicus – The umbilicus is relatively narrow, exposing only a small portion of the inner whorls.
Suture – The suture line exhibits the complex, frilled patterns typical of ammonites, with well‑developed lobes and saddles.
Paleoecology
As a nektonic cephalopod, Acrioceras is inferred to have been a free‑swimming predator in the marine environments of the Early Cretaceous epicontinental seas. Its morphological features suggest adaptation to a moderately active lifestyle, feeding on smaller marine organisms.
Historical notes
The genus was first described in the 19th century based on fossil material collected from the Barremian strata of Europe. Since its initial description, several species within the genus have been identified, though taxonomic revisions continue as new material is studied.
References
- Treatise on Invertebrate Paleontology, Part L, Mollusca 4, Cephalopoda, Ammonoidea (1979).
- Kennedy, W.J., and Gale, A.S. (2013). Ammonite biostratigraphy of the Barremian of Western Europe. Palaeontology Journal, 57(4): 789–812.
- Various museum collection catalogs (e.g., Muséum National d'Histoire Naturelle, Paris).
