In today's world, Helcionelloida continues to be a topic of great relevance and interest to a large sector of the population. Over time, Helcionelloida has managed to remain at the center of attention of academics, professionals and amateurs, demonstrating its importance and impact in different areas of society. Throughout history, Helcionelloida has been the subject of numerous studies, debates and reflections, which has contributed to enriching knowledge on this topic. In this article, we will explore some key aspects related to Helcionelloida, with the aim of delving into its meaning, its evolution and its relevance today.
Helcionelloida Temporal range:
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Latouchella costata | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Subphylum: | Conchifera |
Class: | †Helcionelloida Peel, 1991 |
Orders | |
and see text |
Helcionelloida is an extinct group of ancient molluscs (phylum Mollusca). These are the oldest known conchiferan molluscs, that is, they had a mineralised shell. Some members of this class were mistaken for Monoplacophorans. The class was erected by Peel in 1991.
These animals were untorted and they had a coiled, cone-shaped shell. The majority of species were small (shells being about two millimeters in length and or diameter). Modern reconstructions depict them as resembling snails. The shells of some genera, particularly Yochelcionella, also possessed a "snorkel"-like opening which was most likely used for breathing.
The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005 categorizes members of this taxon within the Paleozoic molluscs of uncertain systematic position, but that taxonomy to not use the name Helcionelloida.
Taxonomy of helcionelloid according to the opinion of P. Yu. Parkhaev:
Gastropoda Cuvier, 1797
Subclass Archaeobranchia Parkhaev, 2001
Subclass Divasibranchia Minichev & Starobogatov, 1975
Subclass Dextrobranchia Minichev & Starobogatov, 1975