Naturalis Biodiversity Center
Info
Platypodiella georgei belongs to the family of Xanthidae, which are also known as mud crabs, pebble crabs, or rubble crabs.
The vast majority of crabs are highly venomous, and it is only proven in a few cases how these crustaceans acquired their venom.
Platypodiella georgei is a fairly small crab, with a carapace of up to 1.72 mm long and 125 mm wide, and you have to look very closely to spot it.
Crabs like Platypodiella georgei warn humans by means of bright, sometimes very strong colors and particularly striking patterns of the high toxicity in their bodies.
Excursus.
The task of scientists is to develop theses and to verify or falsify them by experiment.
Scientists at the Universidad de La Laguna, Spain, set themselves the task of providing evidence for the toxicity of the crab Platypodiella picta. To do this, 60 crabs were brought together with two native Palythoa species, Palythoa caribaeorum and Palythoa aff. clavata, in laboratory experiments for five days.
Result:
The results of this study showed that Platypodiella picta is an active predator of Palythoa species.
The experimental colonies of the crust anemones showed a significant weight loss in the presence of Platypodiella picta for Palythoa aff. clavata and Palythoa caribaeorum, which was even more pronounced in the case of Palythoa caribaeorum!
For those interested, the following can be read here:
https://www.frontiersin.org/10.3389%2Fconf.fmars.2019.08.00160/event_abstract
From the original description:
Habitat:
All but two specimens of Platypodiella georgei were collected under or between encrusting colonies of one or two Palythoa species (Zoantharia). One extensive Palythoa colony in Ruperf's Bay, covering several square meters of irregular rocky substrate, was heavily infested with crabs.
This colony had many irregular, often lumpy elevations, open holes and slits. Most of these lumps, which were hollow inside, were occupied by a crab, with the largest lumps harboring the largest individuals. It is therefore obvious that the crabs themselves influence the growth form of the Palythoa host colony by creating their own cozy, well-protected habitat connected to the outside world by an open tunnel or slit.
The other Palythoa colonies were rather flat, with few irregularities, and contained only a few individuals of P. georgei. As mentioned in “Material”, two very small specimens were found in a large, empty sea cockle [Megabalanus azoricus (Pilsbry, 1921)], which was covered by a colony of Zoanthus cf. sanctaehelenae Carlgren, 1941.
In the case of other Platypodiella species, the conspicuous colors of P. georgei could indicate a warning function, but there is no evidence for this. First of all, the crabs usually live hidden under or embedded in their Zoanthus host colony (at least during the day); and, furthermore, the crabs are certainly not avoided by predatory fish; when the crabs were taken out from under and between their Palythoa host colonies, several fish species (Blennidae, Labridae) were eager to snap any living creature that came along, and one specimen of Platypodiella georgei was actually lost to a Saint Helena wrasses or “greenfish” (Thalassoma sanctaehelenae (Valenciennes, 1839)).
Etymology – The species is named after Mr. Basil A. George, education officer in Jamestown, St. Helena Island.
Many species of the family Xanthidae can be poisonous, although they themselves have no poisonous apparatus (poisonous teeth, poisonous spines, poisonous glands in the skin), the consumption of these crustaceans can even be fatal for humans. Such animals are considered passive-poisonous.
The toxins of crabs (saxitoxin and tetrodotoxin) are produced by endobacteria and stored in the flesh of the crab, these e are highly potent and similar to the neurotoxins of puffer fish and just as deadly.
In its raw and cooked meat, consumption of the crab meat is toxic to humans!
Please be sure to clarify whether the meat of these crabs is toxic or non-toxic before eating it!
Call an emergency doctor immediately at the first signs of poisoning (e.g. breathing problems, muscle cramps)!
The good news is there’s no way you can be exposed to these toxins if you don’t try to eat these crabs – a bite or a jab isn’t going to do the job.
The bad news for those who unwittingly consume these crabs is that cooking the meat isn’t going to make the toxins any less effective.
Fortunately, toxic crabs don’t want to be eaten just as much as we shouldn’t be eating them, so they help us out with their glorious warning colours.
Synonyms:
Atergatis cristatissimo Lockington, 1877 · unaccepted > junior subjective synonym
Atergatis rotundatus Stimpson, 1860 · unaccepted > superseded combination
The vast majority of crabs are highly venomous, and it is only proven in a few cases how these crustaceans acquired their venom.
Platypodiella georgei is a fairly small crab, with a carapace of up to 1.72 mm long and 125 mm wide, and you have to look very closely to spot it.
Crabs like Platypodiella georgei warn humans by means of bright, sometimes very strong colors and particularly striking patterns of the high toxicity in their bodies.
Excursus.
The task of scientists is to develop theses and to verify or falsify them by experiment.
Scientists at the Universidad de La Laguna, Spain, set themselves the task of providing evidence for the toxicity of the crab Platypodiella picta. To do this, 60 crabs were brought together with two native Palythoa species, Palythoa caribaeorum and Palythoa aff. clavata, in laboratory experiments for five days.
Result:
The results of this study showed that Platypodiella picta is an active predator of Palythoa species.
The experimental colonies of the crust anemones showed a significant weight loss in the presence of Platypodiella picta for Palythoa aff. clavata and Palythoa caribaeorum, which was even more pronounced in the case of Palythoa caribaeorum!
For those interested, the following can be read here:
https://www.frontiersin.org/10.3389%2Fconf.fmars.2019.08.00160/event_abstract
From the original description:
Habitat:
All but two specimens of Platypodiella georgei were collected under or between encrusting colonies of one or two Palythoa species (Zoantharia). One extensive Palythoa colony in Ruperf's Bay, covering several square meters of irregular rocky substrate, was heavily infested with crabs.
This colony had many irregular, often lumpy elevations, open holes and slits. Most of these lumps, which were hollow inside, were occupied by a crab, with the largest lumps harboring the largest individuals. It is therefore obvious that the crabs themselves influence the growth form of the Palythoa host colony by creating their own cozy, well-protected habitat connected to the outside world by an open tunnel or slit.
The other Palythoa colonies were rather flat, with few irregularities, and contained only a few individuals of P. georgei. As mentioned in “Material”, two very small specimens were found in a large, empty sea cockle [Megabalanus azoricus (Pilsbry, 1921)], which was covered by a colony of Zoanthus cf. sanctaehelenae Carlgren, 1941.
In the case of other Platypodiella species, the conspicuous colors of P. georgei could indicate a warning function, but there is no evidence for this. First of all, the crabs usually live hidden under or embedded in their Zoanthus host colony (at least during the day); and, furthermore, the crabs are certainly not avoided by predatory fish; when the crabs were taken out from under and between their Palythoa host colonies, several fish species (Blennidae, Labridae) were eager to snap any living creature that came along, and one specimen of Platypodiella georgei was actually lost to a Saint Helena wrasses or “greenfish” (Thalassoma sanctaehelenae (Valenciennes, 1839)).
Etymology – The species is named after Mr. Basil A. George, education officer in Jamestown, St. Helena Island.
Many species of the family Xanthidae can be poisonous, although they themselves have no poisonous apparatus (poisonous teeth, poisonous spines, poisonous glands in the skin), the consumption of these crustaceans can even be fatal for humans. Such animals are considered passive-poisonous.
The toxins of crabs (saxitoxin and tetrodotoxin) are produced by endobacteria and stored in the flesh of the crab, these e are highly potent and similar to the neurotoxins of puffer fish and just as deadly.
In its raw and cooked meat, consumption of the crab meat is toxic to humans!
Please be sure to clarify whether the meat of these crabs is toxic or non-toxic before eating it!
Call an emergency doctor immediately at the first signs of poisoning (e.g. breathing problems, muscle cramps)!
The good news is there’s no way you can be exposed to these toxins if you don’t try to eat these crabs – a bite or a jab isn’t going to do the job.
The bad news for those who unwittingly consume these crabs is that cooking the meat isn’t going to make the toxins any less effective.
Fortunately, toxic crabs don’t want to be eaten just as much as we shouldn’t be eating them, so they help us out with their glorious warning colours.
Synonyms:
Atergatis cristatissimo Lockington, 1877 · unaccepted > junior subjective synonym
Atergatis rotundatus Stimpson, 1860 · unaccepted > superseded combination
