Margined Ramshorn
Planorbis planorbis
This record describes Planorbis planorbis (species). Recorded family: Planorbidae. Recorded order: Hygrophila.
Identification and Appearance
Shell size: 9-18mm, height: 2.5-4 mm. A rather thick and strong shell. It is not glossy and it has a paler keel towards the periphery, past the mid-line but not right at the edge. There are 5 or 6 whorls which increase regularly in size. The mouth may be slightly expanded and sometimes bears a narrow rib inside. The main confusion is likely to be with the Keeled Ramshorn, Planorbis carinatus , which also has a keel. They can be distinguished by the position of the keel and the profile of the shell joining the keel. P. planorbis is flattened on one side with the keel very much at the edge with a rounded shell joining this keel. In P. carinatus the keel is off-centre but not right at one side with the shell more sloping at an angle to reach this keel. Ponds, ditches, and in quiet slow flowing canals and rivers, usually in the shallower parts amongst the water weeds. It is found in most counties of England, and many in Ireland, but is recorded only infrequently from Wales and Scotland.
Classification
- Kingdom
- Animalia
- Phylum
- Arthropoda
- Order
- Hygrophila
- Family
- Planorbidae
- Genus
- Planorbis
Imported taxonomy record. Source availability varies; see the source references and editorial policy below.
Habitat and Range
Habitat
Ponds, ditches, and in quiet slow flowing canals and rivers, usually in the shallower parts amongst the water weeds.
Seasonal Activity
All year round.
Additional species information
Recorded status
It is found in most counties of England, and many in Ireland, but is recorded only infrequently from Wales and Scotland.
About Hygrophila: the wider group
Order-level background for Hygrophila, the group containing Planorbis planorbis. Species-specific details appear above.
Group overview
This is a smaller arthropod order with specialized ecological roles. Arthropods are the most diverse animal phylum, comprising over 80% of all known animal species with approximately 1.2 million described species globally.
Ecological role of the group
Members of this order contribute to broader arthropod ecosystem functions including decomposition, predation, and serving as food sources for vertebrates. Arthropod biodiversity is essential for ecosystem resilience.
Economic and practical significance of the group
While this order has limited direct economic impact, arthropods collectively provide ecosystem services worth trillions of dollars annually through pollination, decomposition, pest control, and nutrient cycling.
Recorded sources for this group: General entomology and arthropod research. Imported estimates may describe particular regions or reporting periods.
Photos of Margined Ramshorn (9)
Frequently Asked Questions About Margined Ramshorn
What is Margined Ramshorn?
Margined Ramshorn (Planorbis planorbis) is a species in the family Planorbidae, within the order Hygrophila.
How big is Margined Ramshorn?
9-18mm, height: 2.5-4 mm. A rather thick and strong shell. It is not glossy and it has a paler keel towards the periphery, past the mid-line but not right at the edge. There are 5 or 6 whorls which increase regularly in size. The mouth may be slightly expanded and sometimes bears a narrow rib inside.
Where is Margined Ramshorn found?
Habitat: Ponds, ditches, and in quiet slow flowing canals and rivers, usually in the shallower parts amongst the water weeds.
When is Margined Ramshorn active?
Margined Ramshorn: seasonal activity - All year round..