Charonia lampas (Linnaeus, 1758) - Knobbed Triton (Marine snail images)

Specimen One - 25 x 12.5cm.
Specimen Two - on left or at bottom in images, caught live off Black Head, Lizard, Cornwall in January 1996; 23 x 11.5cm.

Specimens featured above owned, photographed and images copyright to Dr. Paul Gainey. Added to APHOTOMARINE, with permission of copyright holder on 09.04.20.

Knobbed Triton
Charonia lampas
- reference specimen ventral 1

Knobbed Triton
Charonia lampas
- reference specimen dorsal 1

Knobbed Triton
Charonia lampas
- reference specimen lateral 1

Knobbed Triton
Charonia lampas
- with mm division rule 1

Knobbed Triton
Charonia lampas
- with mm division rule 2

Knobbed Triton
Charonia lampas
- with mm division rule 3

Knobbed Triton
Charonia lampas
- with mm division rule 4

The F+++ quality large dwarf specimen above is 137mm in length. It was live collected by local fishermen off Tabarka, Tunisia, having been caught in nets cast in deep water. Specimen obtained as a reference specimen and photographed by the author on 18.04.20.

Please report this species to the author here by e-mail. I am especially interested in Cornish reports and the potential toxicity of live individuals. More shells are also needed for reference purposes and for identifying this species correctly in the UK.

Charonia lampas or Knobbed Triton is a species chiefly found in the warm temperate / Mediterranean-climate zones, it can also be found to a lesser extent in the tropics and in the colder waters of the UK. It is a species that's at its northern limit in our waters but one that is becoming more frequently caught by fishermen, in lobster / crab pots, set nets and scallop dredges.

From 1976 to 2020 there were nine reports of this species in Cornwall (ERICA database), the majority being since the late 1990s. There is a record from the Channel Islands, from 1999, West of Sark, north of Les Hautes Boues and south of Brehou Is., the species being caught by a commercial fisherman. Three living specimens uncluding one from Hurd's Deep north of the Channel Islands, 1972. Four specimens were landed in Co. Kerry in 1970-71 (O'Riordan, 1972) and three landed off Dover in 1986, so this warmer water species has a history here, and one that is likely to continue with warming seas. The minimum depth for this species is recorded as 8m, the maximum depth 80m. Specimen caught at 80m by the Newlyn boat 'Karen', on 21st March 1975. Specimen from Hurd's Deep could be deeper than 80m. The species is thought to either feed on scallops or starfish, maybe both.

On a personal note I have been interested in this species ever since I started researching the toxic invasive alien nemertean Cephalothrix simula and TTX, like C. simula the gastropod Charonia lampas can contain the neurotoxin tetrodotoxin, TTX, which causes Pufferfish poisoning. In October 2007, in Malaga, Spain there was a non-fatal report of human TTX poisoning involving the ingestion of a Charonia lampas, and from a specimen that was caught off the south coast of Portugal.

Low levels of TTX have been detected in bivalves in the United Kingdom at a few sites on the south coast, the levels being well under EU permitted limits, these may be linked to the prescence of Cephalothrix simula, e.g. at Poole. Charonia lampas represents the first mollusc species that can be found in UK waters that is known to have caused TTX poisoning in humans. It is a known fact that with climate change our waters will warm, the question is, will Charonia lampas numbers increase and will the species then move into shallower warmer water, waters that in certain and unknown locations have been invaded by the TTX producing nemertean Cephalothrix simula.

At present governments are not interested in finding out the distribution of Cephalothrix simula in the UK, fact news! The species is currently considered a low risk non-native species here. This might be so, but the bacteria that produce the TTX within the nemertean must be considered high risk because they can live outside the nemertean and TTX can stay within the environment and can accumulate. Accumulation being more likely in large sheltered bodies of water and in ports and harbours. The question is, in what species will TTX be accumulated here and will it eventually affect critical / commercial food webs.

We will probably eventually find many more species contain and indeed utilize TTX to some degree, e.g. for protection. The ecology of TTX in the UK is not known which is why the report of Charonia lampas here is so important as it is one of the species we do know about. We can make informed judgements as to the species which may contain the neurotoxin here as they may be related in some way to others that are already known to contain it elsewhere, but without toxicity testing it is hard to predict anything. It is also the case that a specific species might contain TTX where found in a sheltered location but not on a highly exposed one, so there are no hard fast rules to follow.

TTX awareness in the UK should not be a ''Citizen Science'' project. We have some of the best marine labs and scientists in Europe, if not the world, the last thing we want is to play catch-up with something that remains hidden by the marine environment. The last thing we need is a TTX related death or for rates of severe food poisoning to increase because we have failed to investigate thoroughly, research and monitor problems or potential problems.

I am sincerely grateful to Dr. Paul Gainey (photography), Dr. Colin French (ERICA records), Simon Taylor (Conch. Soc. records) and Ian Smith for help with the production of this page.

References:
Andrew D. Turner, David Fenwick, Andy Powell, Monika Dhanji-Rapkova, Charlotte Ford, Robert G. Hatfield, Andres Santos, Jaime Martinez-Urtaza, Tim P. Bean, Craig Baker-Austin and Paul Stebbing.
New Invasive Nemertean Species (Cephalothrix simula) in England with High Levels of Tetrodotoxin and a Microbiome Linked to Toxin Metabolism.

Andrew D. Turner, Cowan Higgins, Wendy Higman and James Hungerford
Published: 11 December 2015
Potential Threats Posed by Tetrodotoxins in UK
Waters: Examination of Detection Methodology Used in Their Control

Rodriguez P, Alfonso A, Vale C, Alfonso C, Vale P, Tellez A, Botana LM. First toxicity report of tetrodotoxin and 5,6,11-trideoxyTTX in the trumpet shell Charonia lampas lampas in Europe.

Lisa Guardone, Andrea Maneschi, Valentina Meucci, Laura Gasperetti, Daniele Nucera & Andrea Armani (2019). A Global Retrospective Study on Human Cases of Tetrodotoxin (TTX) Poisoning after Seafood Consumption.

Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence"

Stella Turk.. J. Conch. 29: 29-30 (1976). Charonia lampas (L) (Gastropoda: Cymatiidae) Living off Cornish Coast.

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APHOTOMARINE

An educational resource dedicated mainly to the photography and diversity of marine life that can be found in coastal waters and intertidal areas of Great Britain and Ireland by David Fenwick.

An educational resource dedicated mainly to the photography
and diversity of marine life that can be found in coastal waters
and intertidal areas of Great Britain and Ireland by David Fenwick.