Red Devil Vampire Crabs are decapod

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s part of Brachyura (from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''βραχύς'' = short, ''οὐρά'' = tail/abdomen). They are land living, freshwater crabs from tropical areas and are endemic to Indonesia. Like all other crabs, they have a carapace, two

chelae A chela ()also called a claw, nipper, or pinceris a pincer (biology), pincer-like organ at the end of certain limbs of some arthropods. The name comes from Ancient Greek , through New Latin '. The plural form is chelae. Legs bearing a chela are ...

and ten jointed legs. They are omnivores The species is named after the

Rolf C. Hagen Group Hagen Inc. (officially The Rolf C. Hagen Group of Companies) is a pet supplies company headquartered in Montreal, Quebec, Canada, and founded in 1955 by Rolf C. Hagen with the help of his brothers, Dieter and Horst. Dieter and Horst Hagen join ...

, which supported work by Christian Lukhaup and Christoph D. Schubart, two of the authors of the describing article. G. hagen is often found in the

aquarium trade Fishkeeping is a popular hobby, practiced by aquarists, concerned with keeping fish in a home aquarium or garden pond. There is also a piscicultural fishkeeping industry, serving as a branch of agriculture. Origins of fishkeeping Fish have ...

and it is relatively inexpensive. The common name was given as a marketing move in order to attract more attention to the crab from buyers and keepers. This is a shared characteristic of all ''Geosesarma'' crabs

Environment

''Geosesarma hagen'' is a species of small land-living

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s only found in

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

. The crabs prefer a humid environment with elements from both terrestrial and freshwater aquatic habitats. They steer clear of drier land and although the younger crabs tend to live in closer proximity to the water, they are not aquatic crabs. Young Red Devil crabs spend most of their time in the water as a way to avoid predators. They are used to living in warm humid conditions and their preferred temperature ranges from 24-28 degrees Celsius (75-82 F). There are many species of ''Geosesarma'' crabs living in the same natural habitat in Java, and they can all be easily identified by their bright and unusual colors. They are all known as Vampire Crabs

Morphology

They can reach up to 7 cm (3 in) in length counting the full leg span. Amongst their distinguishing features, ''G. hagen'' has a wider, square shape body, dark brown anterior

carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

and legs, while the posterior of the carapace and the claws/

are instead orange/red. Their

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

is usually gray and they have bright yellow eyes.

Reproduction and Life Cycle

''G. hagen'' can live up to 2 years, but they average about 1.5 years. They undergo molting in order to grow and recover lost legs and limbs within a few months of losing them. They can go through several molts during their lifetime. The Red Devil Vampire crabs are

sexually dimorphic Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

and males have a narrow and slimmer plate while females have a broad plate on their belly and they might also be carrying around some fertilized eggs. Another difference between male and female crabs is in their claws: males have larger and brighter claws while females have smaller claws. Mating occurs when the female is ready to mate and it lasts for several minutes. The females release their eggs in freshwater and each female can carry about 12-24 eggs. Incubation lasts around 30–50 days and the larval stage is completely absent. The hatched crab develops directly and they lack coloration when they are young (they become dark brown and then eventually develop bright adult coloration).

Behavior

Red Devil Crabs are

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

and spend most of their life hidden from the light in order to avoid predation. At night, they become active hunters and scavengers. They will engage in fights over territory, especially between males. They should be housed with plenty of space, even individually, unless breeding is desired. Like with many crabs, ''G. hagen'' shows higher social and behavioral complexity than most invertebrates. They are however often aggressive with crabs of other species, including other ''Geosesarma'' species. They often create their shelters by digging up small amounts of dirt near bodies of water. Though they are not generally thought of as true burrowers, they spend most of their time hidden in these dens.

Ecology

The Red Devils are

omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...

s (though they show a preference for carnivorous prey), and their diet ranges from small detritus and dead plants to fruit flies, woodlice and other bugs. They also are key animals in the microbial loop in the tropics as well as key players for biogeochemical nutrient cycling. (Lidquist et al. 2009)

Relationship with Humans

It is popular in the aquarium trade, where it is sometimes called "Geosesarma red devil"Archived a
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and th
Wayback Machine
or "''Geosesarma'' sp "rot" (''rot'' means "red" in German). All species of '' Geosesarma'' crabs are often called "vampire crabs" in the aquarium trade. The crabs are not known to pose any danger to humans, though their bright coloration may suggest otherwise at a first glance.

References

3. Michael. (2022, February 18). ''Red Devil Crab – Detailed Guide: Care, Diet, and breeding''. Shrimp and Snail Breeder. Retrieved April 7, 2022, from https://aquariumbreeder.com/red-devil-crab-detailed-guide-care/ 4. Freitag, H., Manuel-Santos, M., & Ng, P. K. L. (1892). ''Two new species of Geosesarma de Man, 1892 (crustacea: Brachyura: Sesarmidae) from Palawan, the Philippines''. Archīum Ateneo. Retrieved April 12, 2022, from https://archium.ateneo.edu/biology-faculty-pubs/8/ 5. Lindquist, E. S., et al. (2009). ''Land Crabs as key drivers in ... - Wiley Online Library''. Retrieved from https://onlinelibrary.wiley.com/doi/full/10.1111/j.1469-185X.2008.00070.x 6. Burggren, W., & McMahon, B. R. (2009). ''Biology of the land crabs''. Cambridge University Press. 7. Ng, Peter K. L.; Wowor, Daisy (2019). ''The vampire crabs of Java, with descriptions of five new species from Mount Halimun Salak National Park, West Java, Indonesia (Crustacea: Brachyura: Sesarmidae: Geosesarma).'' https://web.p.ebscohost.com/abstract?site=ehost&scope=site&jrnl=02172445&AN=140243800&h=IzfZIqXBjIe1tn4LM%2brOJNoz6ywTBYFug362mxESHsvblTfmmb4aYlSch3cnPIAPL9gEJ692HYuqQ%2bOwJqCdvQ%3d%3d&crl=c&resultLocal=ErrCrlNoResults&resultNs=Ehost&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d02172445%26AN%3d140243800 8. Yeo, D. C. J., Ng, P. K. L., Cumberlidge, N., Magalhães, C., Daniels, S. R., & Campos, M. R. (1970, January 1). ''Global diversity of crabs (crustacea: Decapoda: Brachyura) in freshwater''. SpringerLink. Retrieved April 25, 2022, from https://link.springer.com/chapter/10.1007/978-1-4020-8259-7_30

External links

*
New species of “vampire crabs” (Geosesarma De Man, 1892) from central Java, Indonesia, and the identity of Sesarma (Geosesarma) nodulifera De Man, 1892 (Crustacea, Brachyura, Thoracotremata, Sesarmidae)Geosesarma crabs mating
- Video of G. hagen crabs mating * Grapsoidea Freshwater crustaceans of Asia Crustaceans described in 2015 Taxa named by Peter Kee Lin Ng {{crab-stub