Invertebrate Zoology Week 2

Ctenophores

How big can Ctenophores get?

a few millimeters to about 5ft.

What is the common name for Ctenophores?

Comb jellies.

Where are Ctenophores native to?

The North Atlantic.

How many species and cryptic species of Ctenophores are there?

150-200 species. ~50 cryptic.

What is the type of symmetry that Ctenophores have?

Rotational.

Are Ctenophores a saltwater and/or freshwater species?

Exclusively marine.

What is the human importance of ctenophores?

Idirectly in commercial use.

What is the larva of ctenophores called?

Cydippid.

What is the Coloblast in ctenophores?

Sticky structure along tentacles, used in prey capture, they stick rather than sting.

What is a sister group of ctenophores?

Cnidaria.

What were ctenophores considered in the 19th century?

The Golden Age of Gelata.

How do you describe the body of a ctenophore?

Translucent, gelatinous.

What is the Macrocilia?

Small teeth-like structure in mouth.

What reproduction does most pelagic ctenophores have?

They are hermaphrodites.

What is an exception of ctenophores who are hermaphrodites?

Genus Ocryopsis.

Where does fertilization happen with ctenophores?

Occurs externally,

What does a cyddipid larva look like?

It’s spherical with 8 ctene rows, apical organ and mouth.

What are benthic ctenophores known as?

Platyctenids.

How do Platyctenids embryos incubate?

Externally in masses attached to a parent or internally inside reproductive chambers.

What is the distribution of ctenophores?

Marine and worldwide, coastal and deep water. Most are pelagic, with large distributions.

What is the distribution of benthic ctenophores?

Narrower range, Indian and Western Pacific Pacific Oceans.

What do benthic species of ctenophores eat?

Crustaceans.

What do benthic species of ctenophores eat?

Copepods.

What else can ctenophores potentionally eat?

Comb jellies.

What is the main sensorial structure of ctenophores?

Apical Organ.

What is the Apical organ composed of?

4 long tufts of cilia (balancers), supporting a statolith. Each balancer controls the movement of a pair of ctene rows.

What are some physiologic features that ctenophores could have?

Photoreceptors, chemoreceptors, and bioluminescence

What do some ctenophores release as an escape behavior?

Luminescent particles.

where does digestion occur in ctenophores?

In the Stomoderm.

How is the size of genomes of ctenophores compared to the rest of the metazoas?

One of the smallest.

What are some facts about ctenophore genetics?

Smallest animal mtDNA and strongly divergent- high rates of sequence evolution.

What is the Position of ctenophores in TOL.

Position in metazoan phylogeny uncertain, for now it shows Ctenophora, Profera, and all other metazoa arising around the same time.

Are there many collections of ctenophores?

Few since they are very fragile to preserve.

What does Polemical mean?

Strongly attract or defend a position.

What are the 3 Classes of Cnidaria?

Scyphozoa (True Jellyfish), Cubozoa (Box Jellyfish), and Staurozoa (Stalked Jellyfish).

How many species and cryptic species are there of Class Scyphozoa?

~230 species, Uknown # of cryptic.

How big does macroscopic Class Scyphozoa grow?

1-2cm

What depths can Class Scyphozoa be found at?

From surface to deep sea.

What is the human importance of Class Scyphozoa?

They are used in commercial fishing in Southeast Asia and China.

What is the biological importance of Class Scyphozoa?

They have a large contribution to the food chain (124 fish species eat jellyfish).

What are Synapomorphies?

An apomorphy that is shared by two or more taxa, hypothesized to have evolved in the most recent common ancestor.

How can a Class Scyphozoa be described?

Umbrella saucer-shaped, hemispherical, flat-dish or high conical.

What are Lappets?

Rounded lobes at the edge of the bell of a Class Scyphozoa.

What is the Rhopalia?

Marginal sense organs at the edge of the umbrella containing statocysts, sensory niches, and sometimes ocelli.

What are the oral arms of a Class Scyphozoa?

It’s 4 developed extensions of manubrium that surrounds the mouth.

What is the larvae of Class Scyphozoa that develop into a medusa?

Ephyrae.

When was the Class Scyphozoa class established?

1883

What is contained in the central stomach of Class Scyphozoa ?

Gastric filaments (cirri) and gonads.

What kind of reproduction do most Class Scyphozoa have?

Gonochoristic reproduction.

What is Gonochoristic?

Separate sexes, that do not change over the organism’s lifetime.

What kind of fertilization does most species of Class Scyphozoa do?

External fertilization.

What is Strolilation?

Asexual reproduction that produces a free-swimming stage called ephyra that grow into a medusa.

Do Class Scyphozoa live in freshwater and/or saltwater?

Both freshwater and saltwater.

What zone does Class Scyphozoa live in?

Epipelagic (surface-200m), neritic (low tide-200m), and bathypelagic (1,000-4,000m) zones.

What kind of waters does Class Scyphozoa live in?

Mainly temperate, but also cold temperate and polar waters.

What are some skills that Class Scyphozoa have?

Light receptors, mechanoreceptors, chemoreceptors, gravity receptors, and hydrostatic pressure receptors.

What are Class Scyphozoa sensitive to?

Salinity and touch.

Class Scyphozoa are ___, they move to catch prey

Planktivorous.

What kind of Class Scyphozoa has a symbiotic relationship with zooxanthellae?

Jellyfish in tropical oligotrophic waters, such as Cassiopea.

What do we have genetics wise for Class Scyphozoa?

Very few whole genomes available due to it being harder to replicate.