Cnidarians | Cnidaria

Cnidarians | Cnidaria

Description
Description

Cnidarians, a diverse group including jellyfish, corals, sea anemones, and hydra, are distinguished by their radial symmetry and cnidocytes – specialized cells used for capturing prey. These aquatic invertebrates inhabit both salt and freshwater environments, from deep oceans to shallow reefs. Cnidarians are among the oldest multicellular organisms, with a fossil record dating back over 500 million years, indicating their resilience and adaptability. They play vital roles in marine ecosystems, with coral reefs providing habitats for numerous species. Cnidarian diversity reflects a broad evolutionary tree, showcasing various survival strategies and life cycles in their aquatic realms.

Anatomy
Anatomy

Cnidarians are simple yet fascinating creatures. They generally have a soft body made up of two layers: an outer protective layer and an inner layer for digestion. They lack bones and a centralized nervous system. Instead, they have a nerve net for basic movements and responses. Central to their anatomy are cnidocytes, unique cells that can sting and capture prey. Some, like jellyfish, drift with currents, while others, like corals, are anchored to the seafloor. They don't have organs for speech or complex senses, but they can detect changes in their environment, like touch and light, aiding in their survival.

Human Interaction
Human Interaction

Humans have a mixed relationship with cnidarians. Historically, jellyfish stings have plagued swimmers, while the beauty of coral reefs has fascinated divers. In popular culture, films like "Finding Nemo" have brought the vivid world of corals to the global audience. Medicinally, research on cnidarians has contributed to understanding nerve cell function and regeneration.

On the conservation front, efforts are underway to protect coral reefs, which are vital marine ecosystems threatened by climate change, pollution, and overfishing. The restoration of these underwater habitats is crucial, showcasing a growing human commitment to preserving these intriguing creatures and their environments.

Common Questions
Common Questions
What do cnidarians use for defense?

Cnidarians are aquatic animals with two body forms (the ectoderm and endoderm separated by a mesoglea). To capture prey or even defend themselves, cnidarians have unique and well-developed specialized cells in their mouths and tentacles for stinging attackers. These cells, called cnidocytes, have toxins that are released when their body is touched.

How do cnidarians reproduce?

Sexual and asexual reproduction are the forms of reproduction seen among cnidarians. Besides, some are hermaphrodites — capable of producing both eggs and sperms at the same time. However, asexual reproduction is the most common in this species. Sexual reproduction may occur only in one phase of a cnidarian’s life cycle.

Do cnidarians have brains?

What cnidarians have are diffuse nets of nerves that coordinate messages around their bodies. Research shows that these nets of nerves are just as complex as that of human beings. In addition, some like jellyfish, have no heart or eyes. Most cnidarians also have a transparent body covered in a chitinous exoskeleton.

Animals

* Under Development *

2.36”-4.33” | 6-11 cm
5”-9.84” | 12.7-25 cm
17.7”-35” | 45-89 cm
6-18 months
Atlantic Sea Nettle
11.000
25.000
89.000
1.50
300
GUIDE
3D
Atlantic Sea Nettle
.79”-6.7” | 2-17 cm
.79”-6.7” | 2-17 cm
1.6”-13.8” | 4-35 cm
Atolla Jellyfish
17.000
17.000
35.000
1200
GUIDE
3D
Atolla Jellyfish
12.6”-47” | 32-119 cm
15.75”-59” | 40-150 cm
29”-108” | 74-274 cm
55-88 lb | 25-40 kg
2-6 months
Barrel Jellyfish
119.000
150.000
274.000
40.000
0.50
6400
GUIDE
3D
Barrel Jellyfish
8.3”-18.9” | 21-48 cm
16”-36” | 40.6-91.4 cm
44”-104” | 112-264 cm
6-12 months
Black Sea Nettle Jellyfish
48.000
91.400
264.000
1.00
350
GUIDE
3D
Black Sea Nettle Jellyfish
.59”-6.3” | 1.5-16 cm
.47”-3.94” | 1.2-10 cm
.59”-6.3” | 1.5-16 cm
Bloodybelly Comb Jellyfish
16.000
10.000
16.000
100
GUIDE
3D
Bloodybelly Comb Jellyfish
27.6”-35.4” | 70-90 cm
31.5”-39.4” | 80-100 cm (Diameter)
31.5”-39.4” | 80-100 cm (Diameter)
Blue Coral
90.000
100.000
100.000
17400
GUIDE
3D
Blue Coral
7.1”-13.8” | 18-35 cm
9.84”-17.72” | 25-45 cm
24.8”-44.9” | 63-114 cm
1 year
Blue Jellyfish
35.000
45.000
114.000
1.00
5800
GUIDE
3D
Blue Jellyfish
9.8”-19.7” | 25-50 cm
11.8”-23.6” | 30-60 cm (Diameter)
11.8”-23.6” | 30-60 cm (Diameter)
Bubble Coral
50.000
60.000
60.000
5300
GUIDE
3D
Bubble Coral
5.5”-7.9” | 14-20 cm
7.1”-9.84” | 18-25 cm
7.5”-10.6” | 19-27 cm
.31-3 lb | .14-1.38 kg
3-6 months
Cannonball Jellyfish
20.000
25.000
27.000
1.380
0.50
12000
GUIDE
3D
Cannonball Jellyfish
3.5”-6.3” | 9-16 cm
5.9”-10” | 15-25.4 cm
16.5”-27.2” | 42-69 cm
.44-5.3 lb | .2-2.4 kg
1 year
Compass Jellyfish
16.000
25.400
69.000
2.400
1.00
5600
GUIDE
3D
Compass Jellyfish
8.7”-19.7” | 22-50 cm
9.84”-23.62” | 25-60 cm
13”-30.7” | 33-78 cm
.04-.89 lb | .02-.4 kg
3-6 months
Crowned Jellyfish
50.000
60.000
78.000
0.400
0.50
5
GUIDE
3D
Crowned Jellyfish
.5”-5.9” | 1.2-15 cm
.8”-10” | 2-25.4 cm
1.2”-14.2” | 3-36 cm
2-6 months
Crystal Jellyfish
15.000
25.400
36.000
0.50
1500
GUIDE
3D
Crystal Jellyfish
.3”-.63” | .8-1.6 cm
.39”-.79” | 1-2 cm
.67”-1.34” | 1.7-3.4 cm
Darth Vader Jellyfish
1.600
2.000
3.400
40
GUIDE
3D
Darth Vader Jellyfish
4’-8’ | 1.22-2.43 m
11.5’-13’ | 3.5-3.96 m (Diameter)
11.5’-13’ | 3.5-3.96 m (Diameter)
Elkhorn Coral
243.000
396.000
396.000
1450
GUIDE
3D
Elkhorn Coral
5.1”-6.3” | 13-16 cm
5.9”-7.9” | 15-20 cm (Diameter)
5.9”-7.9” | 15-20 cm (Diameter)
Finger Coral
16.000
20.000
20.000
1340
GUIDE
3D
Finger Coral
4.7”-5.9” | 12-15 cm
4.72”-5.91” | 12-15 cm
8.3”-10.6” | 21-27 cm
4-6 months
Flower Hat Jelly
15.000
15.000
27.000
0.50
150
GUIDE
3D
Flower Hat Jelly
1.6”-8.7” | 4-22 cm
2.36”-11.8” | 6-30 cm
2”-10.2” | 5-26 cm
4-6 months
Fried Egg Jellyfish
22.000
30.000
26.000
0.50
2000
GUIDE
3D
Fried Egg Jellyfish
10.2”-41.3” | 26-105 cm
15.75”-78.75” | 40-200 cm
28.3”-143” | 72-362 cm
200-480 lb | 91-217 kg
1 year
Lion’s Mane Jellyfish
105.000
200.000
362.000
217.000
1.00
6900
GUIDE
3D
Lion’s Mane Jellyfish
.79”-2.75” | 2-7 cm
1.18”-3.94” | 3-10 cm
3.15”-11” | 8-28 cm
6-9 months
Mauve Stinger
7.000
10.000
28.000
0.75
2300
GUIDE
3D
Mauve Stinger
3.94”-9.1” | 10-23 cm
5.91”-13.78” | 15-35 cm
7.1”-16.5” | 18-42 cm
.01-.07 lb | .01-.03 kg
8-12 months
Moon Jellyfish
23.000
35.000
42.000
0.030
1.00
56000
GUIDE
3D
Moon Jellyfish
7.9”-11.8” | 20-30 cm
11.8”-19.7” | 30-50 cm (Diameter)
11.8”-19.7” | 30-50 cm (Diameter)
Organ Pipe Coral
30.000
50.000
50.000
2400
GUIDE
3D
Organ Pipe Coral
22”-27.2” | 56-69 cm
30”-36” | 76.2-91.4 cm
55”-67” | 140-170 cm
30-50 lb | 14-23 kg
Pink Meanie Jellyfish
69.000
91.400
170.000
23.000
1200
GUIDE
3D
Pink Meanie Jellyfish
2”-5.1” | 5-13 cm
4.72”-11.8” | 12-30 cm
8.7”-23.2” | 22-59 cm
1 year
Portuguese Man o' War
13.000
30.000
59.000
1.00
17000
GUIDE
3D
Portuguese Man o' War
3.5”-5.1” | 9-13 cm
2.95”-3.94” | 7.5-10 cm
6.7”-9.1” | 17-23 cm
Red Paper Lantern Jellyfish
13.000
10.000
23.000
5
GUIDE
3D
Red Paper Lantern Jellyfish
3’-5’ | .91-1.52 m
3.3’- 9.8’ | 1-3 m (Diameter)
3.3’- 9.8’ | 1-3 m (Diameter)
Staghorn Coral
152.000
300.000
300.000
2500
GUIDE
3D
Staghorn Coral
13.4”-14.2” | 34-36 cm
17.7”-19.7” | 45-50 cm
36.2”-41.7” | 92-106 cm
20-24 lb | 9-11 kg
1 year
White-Spotted Jellyfish
36.000
50.000
106.000
11.000
1.00
410
GUIDE
3D
White-Spotted Jellyfish
Crowned Jellyfish (Cephea cephea)
Measured comparison illustration of the size of a Crowned Jellyfish to a typical person and jellyfish

The Crowned jellyfish, known as Cephea cephea, is a crown jellyfish usually found in the cold water up to 3,000 feet below the surface in the Indo-Pacific ocean. The Crowned jellyfish is purple and blue in color, bioluminescent, and has the distinctive bell shape of crown jellies. The Crown jellyfish also has warts that protrude off its body. The Crowned jellyfish is one of the most venomous jellyfish, yet not to humans; therefore, it is eaten as a delicacy and even used medically in certain Asian countries. The Crowned jellyfish, like most other jellies, has tentacles that can be used to stun and capture its prey.

Crowned Jellyfish have a bell width between 9.84”-23.62” (25-60 cm), bell height of 8.7”-19.7” (22-50 cm), and overall length of 13”-30.7” (33-78 cm). The typical lifespan of the Crowned Jellyfish is 3-6 months with a weight between .04-.89 lb (.02-.4 kg).

Scaled collection of drawings of Crowned Jellyfish in front and side poses
The Crowned jellyfish, known as Cephea cephea, is a crown jellyfish usually found in the cold water up to 3,000 feet below the surface in the Indo-Pacific ocean. The Crowned jellyfish is purple and blue in color, bioluminescent, and has the distinctive bell shape of crown jellies.

Crowned Jellyfish have a bell width between 9.84”-23.62” (25-60 cm), bell height of 8.7”-19.7” (22-50 cm), and overall length of 13”-30.7” (33-78 cm). The typical lifespan of the Crowned Jellyfish is 3-6 months with a weight between .04-.89 lb (.02-.4 kg).

Scaled collection of drawings of Crowned Jellyfish in front and side poses
Crowned Jellyfish (Cephea cephea)
Height:
8.7”-19.7” | 22-50 cm
Width:
9.84”-23.62” | 25-60 cm
Length:
13”-30.7” | 33-78 cm
Depth:
Weight:
.04-.89 lb | .02-.4 kg
Area:
Scientific Name
Cephea cephea
Lifespan
3-6 months

Drawings include:

Crowned Jellyfish side elevation, front, top

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Bubble Coral (Plerogyra sinuosa)
Scale illustration of an average Bubble Coral compared to other coral species and a person

In the Red Sea and even the Indo-Pacific oceanic environment, the Bubble Coral (Plerogyra sinuosa) is often seen bubbling or showing a variety of bubble sizes. During the day, the bubbles are large but small at night, leaving the coral to display long sweeping tentacles that can bite. The bubbles are translucent or have pale strips when inflated and less translucent when retracted. Other communities call it bladder coral, grape coral, pearl coral, and octobubble coral. The Bubble coral prefers moderately lit areas and can be tan, pale green, or pink.

The Bubble Coral has an overall colony diameter between 11.8”-23.6” (30-60 cm) and height of 9.8”-19.7” (25-50 cm). The diameters of the individual branches are roughly 1”-1.6” (2.5-4 cm) with individual heights between 1.6”-2.75” (4-7 cm).

Series of illustrations of the Bubble Coral from multiple views
In the Red Sea and even the Indo-Pacific oceanic environment, the Bubble Coral (Plerogyra sinuosa) is often seen bubbling or showing a variety of bubble sizes. During the day, the bubbles are large but small at night, leaving the coral to display long sweeping tentacles that can bite.

The Bubble Coral has an overall colony diameter between 11.8”-23.6” (30-60 cm) and height of 9.8”-19.7” (25-50 cm). The diameters of the individual branches are roughly 1”-1.6” (2.5-4 cm) with individual heights between 1.6”-2.75” (4-7 cm).

Series of illustrations of the Bubble Coral from multiple views
Bubble Coral (Plerogyra sinuosa)
Height:
9.8”-19.7” | 25-50 cm
Width:
11.8”-23.6” | 30-60 cm (Diameter)
Length:
Depth:
11.8”-23.6” | 30-60 cm (Diameter)
Weight:
Area:

Individual Height: 1.6”-2.75” | 4-7 cm

Individual Diameter: 1”-1.6” | 2.5-4 cm

Scientific Name
Plerogyra sinuosa
Lifespan

Drawings include:

Bubble Coral top view, side (assorted)

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Atlantic Sea Nettle (Chrysaora quinquecirrha)
Measured comparison illustration of the size of a Atlantic Sea Nettle to a typical person and jellyfish

The Atlantic Sea Nettle, known as Chrysaora quinquecirrha, is a relatively small jellyfish of various colors found along the Atlantic coast of the United States. When compared to the Pacific Sea Nettle, the Atlantic Sea Nettle is smaller. The Atlantic Sea Nettle, though small, is capable of delivering a potent sting. The Atlantic Sea Nettle’s tentacles are covered in coiled stinging filaments ready to release once they are touched. This sting, while not inherently dangerous to humans, is able to kill small prey and deter predators. The Atlantic Sea Nettle is carnivorous and feeds on small marine critters and uses its powerful sting to stun and kill its food.

Atlantic Sea Nettles have a bell width between 5”-9.84” (12.7-25 cm), bell height of 2.36”-4.33” (6-11 cm), and overall length of 17.7”-35” (45-89 cm). The typical lifespan of the Atlantic Sea Nettle is 6-18 months.

Scaled collection of drawings of Atlantic Sea Nettle in front and side poses
The Atlantic Sea Nettle, known as Chrysaora quinquecirrha, is a relatively small jellyfish of various colors found along the Atlantic coast of the United States. When compared to the Pacific Sea Nettle, the Atlantic Sea Nettle is smaller.

Atlantic Sea Nettles have a bell width between 5”-9.84” (12.7-25 cm), bell height of 2.36”-4.33” (6-11 cm), and overall length of 17.7”-35” (45-89 cm). The typical lifespan of the Atlantic Sea Nettle is 6-18 months.

Scaled collection of drawings of Atlantic Sea Nettle in front and side poses
Atlantic Sea Nettle (Chrysaora quinquecirrha)
Height:
2.36”-4.33” | 6-11 cm
Width:
5”-9.84” | 12.7-25 cm
Length:
17.7”-35” | 45-89 cm
Depth:
Weight:
Area:
Scientific Name
Chrysaora quinquecirrha
Lifespan
6-18 months

Drawings include:

Atlantic Sea Nettle side elevation, front, top

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Black Sea Nettle Jellyfish (Chrysaora achlyos)
Measured comparison illustration of the size of a Black Sea Nettle Jellyfish to a typical person and jellyfish

The Black Sea Nettle, known scientifically as Chrysaora achlyos, regarded as a giant jelly has a large purplish bell with long, lacy arms that function as mouths. In addition to its mouth-arms, the Black Sea Nettle has tentacles that are even longer than its mouth-arms. The Black Sea Nettle is usually found in the warm waters of the Pacific ocean from Monterey Bay to Baja California. Overall, Black Sea Nettle sightings are rare, but when they are seen they usually appear in large swarms coinciding with red seas and abundance of zooplankton.

Black Sea Nettle Jellyfish have a bell width between 16”-36” (40.6-91.4 cm), bell height of 8.3”-18.9” (21-48 cm), and overall length of 44”-104” (112-264 cm). The typical lifespan of the Black Sea Nettle Jellyfish is 6-12 months.

Scaled collection of drawings of Black Sea Nettle Jellyfish in front and side poses
The Black Sea Nettle, known scientifically as Chrysaora achlyos, regarded as a giant jelly has a large purplish bell with long, lacy arms that function as mouths. In addition to its mouth-arms, the Black Sea Nettle has tentacles that are even longer than its mouth-arms.

Black Sea Nettle Jellyfish have a bell width between 16”-36” (40.6-91.4 cm), bell height of 8.3”-18.9” (21-48 cm), and overall length of 44”-104” (112-264 cm). The typical lifespan of the Black Sea Nettle Jellyfish is 6-12 months.

Scaled collection of drawings of Black Sea Nettle Jellyfish in front and side poses
Black Sea Nettle Jellyfish (Chrysaora achlyos)
Height:
8.3”-18.9” | 21-48 cm
Width:
16”-36” | 40.6-91.4 cm
Length:
44”-104” | 112-264 cm
Depth:
Weight:
Area:
Scientific Name
Chrysaora achlyos
Lifespan
6-12 months

Drawings include:

Black Sea Nettle Jellyfish side elevation, front, top

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Portuguese Man o' War (Physalia physalis)
Dimensioned comparison drawing of the Portuguese Man o' War compared to other jellyfish and a person

The Portuguese Man O’ War, known scientifically as Physalia physalis, is often mistaken for a jellyfish, when in reality it is a siphonophore, a colonial organism made up of multiple smaller zooids. The Portuguese Man O’ War is considered to be the same species as the Pacific Man O’ War. The Portuguese Man O’ War consists of its top, called a pneumatophore, which is mainly translucent blue with hints of purple, that is filled with carbon monoxide and acts as a sail and flotation device for the organism. Dangling from its top are the Portuguese Man O’War’s killer tentacle zooids which kill fish, and have even killed humans, as it floats along the top of the ocean surface. The Portuguese Man O’ War lives solely on the ocean’s surface making it a member of the neuston, a highly complex ecology of ocean surface dwelling creatures, of which little is known.

Portuguese Man o' Wars have a bell width between 4.72”-11.8” (12-30 cm), bell height of 2”-5.1” (5-13 cm), and overall length of 8.7”-23.2” (22-59 cm). The typical lifespan of the Portuguese Man o' War is 1 year.

Set of scaled elevation drawings of the Portuguese Man o' War viewed from the front and side
The Portuguese Man O’ War, known scientifically as Physalia physalis, is often mistaken for a jellyfish, when in reality it is a siphonophore, a colonial organism made up of multiple smaller zooids. The Portuguese Man O’ War is considered to be the same species as the Pacific Man O’ War.

Portuguese Man o' Wars have a bell width between 4.72”-11.8” (12-30 cm), bell height of 2”-5.1” (5-13 cm), and overall length of 8.7”-23.2” (22-59 cm). The typical lifespan of the Portuguese Man o' War is 1 year.

Set of scaled elevation drawings of the Portuguese Man o' War viewed from the front and side
Portuguese Man o' War (Physalia physalis)
Height:
2”-5.1” | 5-13 cm
Width:
4.72”-11.8” | 12-30 cm
Length:
8.7”-23.2” | 22-59 cm
Depth:
Weight:
Area:
Scientific Name
Physalia physalis
Lifespan
1 year

Drawings include:

Portuguese Man o' War side elevation, front, top

Downloads

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