Echiniscoides sigismundi

Geographic Range

Echiniscodies sigismundi individuals are found in aquatic environments. They have very high species richness, though populations tend to be rather small. Populations are mostly present in the Mediterranean Sea, but also have populations located in the Arctic Ocean, the Caribbean, the North Atlantic Ocean, and the South Pacific Ocean. There are several different subspecies that scientists are debating elevating to the species level which is making it more difficult to find the geographic range of these tardigrades. (Gąsiorek and Kristensen, 2022; Guidetti and ver der Land, 2016; Ocean Biodiversity Information System, 2015)


Echiniscodies sigismundi individuals are typically found in intertidal barnacles and seaweeds. Water bears need to stay close to water, otherwise they will dry out, so they have also been found living on moss or lichen, but those are less common examples. They live close to the surface, typically from 0-10 meters of depth. This tardigrade lives in salty environments with a PSU scale of 30-35 and temperatures ranging from 0-20, however, many have been seen expanding past this typical view. (Dimery, 2019; EOL, 2022; Gąsiorek and Kristensen, 2022; Guidetti and ver der Land, 2016; Hobart and Crisp, 1954; Jo, et al., 2022; Nelson, 2002; Ocean Biodiversity Information System, 2015)

  • Range depth
    0 to 10-15 m
    0.00 to ft
  • Average depth
    25 m
    82.02 ft

Physical Description

Echiniscoides sigismundi individuals are microscopic organisms with 8 legs and a mouth on the center of their face. They are translucent and only the females develop eyes. They are cylindrical and each leg can have a range of 7-13 claws, with the fourth pair of legs having one claw less than the others. (Gąsiorek and Kristensen, 2022; Grzimek's Animal Life Encyclopedia, 2023)

  • Sexual Dimorphism
  • female larger
  • sexes shaped differently
  • Average length
    0.002 mm
    0.00 in
  • Average wingspan
    0.5 mm
    0.02 in


Females will lay 30 eggs on average per ovulation. Once laid, the eggs will take roughly 40 days to hatch. Echiniscodies sigismundi individuals experience ecdysis and incomplete metamorphosis, and can perform this up to 4 times during their lifetime. (Glime, 2017; Glime, 2020; Grzimek's Animal Life Encyclopedia, 2023)


Not much is known about the mating systems of Echiniscoides sigismundi individuals. Some other species of tardigrade have both polyandrous and polygynous mating systems, sometimes even in the same population, but more research needs to be done to see if this is replicated in E. sigismundi. (Rebecchi, et al., 2007)

Echiniscoides sigismundi individuals breed during the fall and winter seasons and roughly produce 30 offspring in that time frame. Eggs hatch 40 days after being laid on average. They are able to reproduce asexually through parthenogenesis. Females also have a structure that allows them to grab sperm out of the male through insertion. (Glime, 2017; Grzimek's Animal Life Encyclopedia, 2023)

  • Breeding interval
    49-50 Days
  • Breeding season
  • Range number of offspring
    30 to 40
  • Average number of offspring
  • Average gestation period
    40 days
  • Average age at sexual or reproductive maturity (female)
    9-10 days

Not much is known about the parental investment of Echiniscoides sigismundi. However, most species of tardigrades do not show any form of parental investment, so it is likely Echiniscoides sigismundi also do not show any.

  • Parental Investment
  • no parental involvement


In most cases, Echiniscodies sigismundi individuals will live around a few months to 2 years. However, when they enter cryptobiosis, E. sigismundi individuals can last decades without food or water. (Glime, 2017; Grzimek's Animal Life Encyclopedia, 2023)

  • Average lifespan
    Status: wild
    30+ years
  • Average lifespan
    Status: captivity
    2.5 years
  • Average lifespan
    Status: wild
    2 years
  • Average lifespan
    Status: captivity
    Few months


The main behavioral pattern Echiniscoides sigismundi individuals are known for, as well as all other species of tardigrade, is cryptobiosis. This defines when a creature enters a state of inactivity due to environmental stressors. E. sigismundi individuals will perform this by curling up into a ball. In this state, E sigismundi individuals has been shown to survive in extreme hot and cold, UV radiation, being frozen, the vacuum of space, and more. E. sigismundi have been recorded to be in this state for over 30 years without needing any additional food or water. The name tardigrade also means "slow walker", first described in 1776. (EOL, 2022; Gąsiorek and Kristensen, 2022; Glime, 2017; Glime, 2020; Grzimek's Animal Life Encyclopedia, 2023; Ocean Biodiversity Information System, 2015)

Home Range

Most of the life of an Echiniscoides sigismundi is suspected to be spent on the barnacle or seaweed where they are first born due to its slow speed and environmental needs, though more research is needed to be done to confirm this. (Gąsiorek and Kristensen, 2022; Glime, 2017; Grzimek's Animal Life Encyclopedia, 2023)

Communication and Perception

The specific method of communication for Echiniscoides sigismundi individuals is currently unknown. Female E. sigismundi individuals will develop large black eyes that now comprise a single pigment cup cells and one or two microvillous sensory cells. (Gąsiorek and Kristensen, 2022)

Food Habits

Echiniscoides sigismundi individuals are omnivorous predators, having to go out and hunt food for themselves. Because of their slow disposition, their most common food source tends to be algae, but they will also eat certain species of rotifers, nematodes, fungi, cyanobacteria, and even smaller tardigrades. E. sigismundi individuals have a pair of stylets that form essentially a straw where they are able to suck out the cell contents of their prey. (Gąsiorek and Kristensen, 2022; Glime, 2017; Grzimek's Animal Life Encyclopedia, 2023)

  • Animal Foods
  • aquatic or marine worms
  • other marine invertebrates
  • Plant Foods
  • algae
  • Other Foods
  • fungus
  • microbes


No predatory defenses are currently known for Echiniscoides sigismundi. Some related species have flat proteins that resemble glass known as the Tardigrade Disordered Protein (TDP) which has been used to stop predators, but more research needs to be done to see if this protein exists in E. sigismundi. Predators for E. sigismundi include nematodes and larger tardigrades. (Glime, 2017)

  • Known Predators
    • Nematodes, Other Tardigrades

Ecosystem Roles

Because of the patchiness of their populations, there is not enough information to find out a lot about Echiniscoides sigismundi’s role in the ecosystem. They do tend to be predators of a lot of species in their habitat, but that can vary depending on location. There have been a few instances of commensal or parasitic relationships with adult barnacles, but the exact relationship is unknown. (Gąsiorek and Kristensen, 2022; Glime, 2017)

Commensal/Parasitic Species
  • Adult Barnacles

Economic Importance for Humans: Positive

Echiniscoides sigismundi have had nearly no impact on the human population. However, the cryptobiosis observed in them has sparked interest in the medical community, specifically provoking research into the preservation of cells and organs. (Grzimek's Animal Life Encyclopedia, 2023)

Economic Importance for Humans: Negative

Currently there are no known negative impacts on humans due to Echiniscoides sigismundi.

Conservation Status

There are no special conservation measures put in place for Echiniscoides sigismundi.


Killian Garnand (author), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.


Arctic Ocean

the body of water between Europe, Asia, and North America which occurs mostly north of the Arctic circle.

Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map


on or near the ocean floor in the deep ocean. Abyssal regions are characterized by complete lack of light, extremely high water pressure, low nutrient availability, and continuous cold (3 degrees C).


reproduction that is not sexual; that is, reproduction that does not include recombining the genotypes of two parents

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


the nearshore aquatic habitats near a coast, or shoreline.


a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease


animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.


union of egg and spermatozoan


An animal that eats mainly plants or parts of plants.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body

intertidal or littoral

the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


having the capacity to move from one place to another.


an animal that mainly eats fungus

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.


an animal that mainly eats all kinds of things, including plants and animals


development takes place in an unfertilized egg


An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).


Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).


the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.


having more than one female as a mate at one time


structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

seasonal breeding

breeding is confined to a particular season


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


lives alone


uses touch to communicate


uses sight to communicate


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Jo, S., H. Stop Kim, Y. Na Choi. 2022. Seasonal Fluctuations in the Abundance of Marine Tardigrades (Heterotardigrada: Echiniscoides sigismundi, Styraconyx haploceros) Inhabiting Fistulobalanus albicostatus, an Intertidal Barnacle on the West Coast of Korea. Ocean Science Journal, 57: 334-344. Accessed February 12, 2023 at

Jønsson, K., T. Hygum, K. Andersen, L. Clausen, N. Møbjerg. 2016. "Tolerance to Gamma Radiation in the Marine Heterotardigrade, Echiniscoides sigismundi" (On-line). PLOS One. Accessed February 12, 2023 at

Nelson, D. 2002. Current Status of the Tardigrada: Evolution and Ecology. Integrative and Comparative Biology, 42/3: 652-659. Accessed February 12, 2023 at,arthropods%20also%20ablate%20tardigrade%20populations..

Ocean Biodiversity Information System, 2015. "Echiniscoides sigismundi (M. Schultze, 1865)" (On-line). Ocean Biodiversity Information System. Accessed February 12, 2023 at

Rebecchi, L., V. Rossi, T. Altiero, R. Bertolani, P. Menozzi. 2007. "ResourceGate" (On-line). Reproductive modes and genetic polymorphism in the tardigrade Richtersius coronifer (Eutardigrada, Macrobiotidae). Accessed April 30, 2023 at