1. A study of the present knowledge and missing information
of the order Corallimorpharia (Cnidaria: Zoantharia)
I am Ha-Rim Cha, and a second-year graduate student of the department of EEB
I am really happy that I get a chance to give a presentation and to introduce my research project in SigmaXi competition.
As you can see in the title, today I would like to talk the the order Corallimorpharia.
Ha-Rim Cha
Department of Ecology and Evolutionary Biology
The University of Kansas

2. Corallimorpharia One of six orders of Zoantharia
Coral-like sea anemones
Solitary or colonial polyps without skeleton
Current Classification
- four families, 13 genera, and 50 species
Widely distributed
- from tropical to polar areas and
from shallow to deep water
Corallimorpharia is one of six orders of Zoantharia, also called Hexacorallia. Because of intermediate characters between stony corals and sea anemones, this group often called coral-like sea anemones, and the common name is mushroom corals.
Corallimorpharians are solitary or colonial polyps without skeleton, and according to the current classification, four families, 13 genera, and 50 species are included.
These animals distribute very widely in the seas. From tropical to polar area and from shallow to deep water.
The horizontal and vertical wide range of distribution allow the significance of the global scale research of this taxon.
Also these animals are very famous and common in aquariums. So, I believe that you already have seen these animals at least once. Even though they just called mushroom corals, you can see corallimorpharians in PET WORLD on 23rd St. in Lawrence.

3. What do they look like? Plate-like body Family Ricordeidae Watzl, 1922
Family Discosomatidae Duchassaing de Fombressin and Michelotti, 1864
Here are some more visual information about the morphology.
Corallimorpharians can be fall into two groups based on morphology.
The first group has plate-like body, and can be characterized by numerous short and blunt tip tentacles.
Family Ricordeidae and family Discosomatidae are included.
Among them, a member of this group, Amplexidiscus fenetrafer is the largest species, which has the width of oral disk up to 450 mm.
(Photos by Vincent B. Hargreaves)

4. Family Sideractiidae Danielssen, 1890
Cylindrical body
Family Sideractiidae Danielssen, 1890
Family Corallimorphidae Hertwig, 1882
The second group comprising two families, Sideractiidae and Corallimorphidae, has cylindrical body which is similar to sea anemones.
The members of second group have capitate tentacles.
Most of members are small and the size of species of genus Corynactis is around 10 to 20 mm in width of column.

5. Characters Examined Body shape / size Tentacles shape / number /
arrangement
Sphincter muscles
Nematocysts composition and distribution
Ecology
In addition to body shape and tentacle shape, corallimorpharians have many characters significantly considered in taxonomy. I listed five main categories examined. First is body shape and size, and second category is tentacle shape, number and arrangement.
Tentacle shape of corallimorpharians can be distinguished to four types. This is capitate tentacles, which has globular ends which contains dense nematocysts at the tip of each tentacle. The other three are short and simple, or branched, or dot-like tentacles. The number and arrangement of tentacles varies within group.
Third character category is sphinter muscle. This is located at the upper part of column and the development of this muscle is related with the contraction and expansion of animals.
Fourth is the nematocysts composition and distribution. Nematocysts are stinging cells all cnidarians have, and each species has different kinds and different size of nematocysts at different part of body. This type of nematocyst, which is large up to 200 um in length and has thick thread in capsule, is called holotrichs. Especially, the presence of holotrichs in corallimorpharians is the similarity to stony corals.
The last category is ecology. Ecological character includes symbiotic relationship with golden brown algae, called zooxanthellae, and with other marine animals. Also habitat character,for example, the depth, temperature, and other oceanography of a certain area, can be included
(by Scott R. Santos)

6. Problems Now, we know corallimorpharians.
Then, what is the problem in this group?
Previously I mentioned, the order Corallimorpharia comprises 13 genera.
However, each genus has incomplete information for comparing between genera. So, people have had hard time to find clear boundary of each genus. Then, finally, it is almost impossible to study at the species level.

7. What is known? Body shape - cylindrical or plate-like Tentacle shape
Family Corallimorphidae
Family Sideractiidae
Family Ricordeidae
Family Discosomatidae
Occurrence depth
Capitate tentacles
So, I looked through literature including original descriptions, and figured out which information is known and what is not known. There are three characters clearly diagnosed for each genus.
First is the morphology of body, second is tentacle shape. Capitate tentacles are common in the cylindrical body group, and the other three are short and simple, or branched, or dot-like tentacles. These three types are common in the first group that has plate-like body.
The third well-known character is the depth of habitat.
For example, the members of genus Corallimorphus occur in 4 km deep, and a species of genus Nectactis lives in 5 km deep.
While, the member of genus Corynactis and genus Discosoma are abundant in shallow water.
Short, simple or branched, and
dot-like tentacles

8. What is unknown or partially known?
Most detailed information
The problem of the order Corallimorpharia come from unknown or partially known information of genera.
Except recently described three genera, Amplesidiscus, Pseudocorynactis, and Sphincteractis, most genera lack many detailed information including type related.
In taxonomy, each genus has to have type specimens of type species. Type specimens of type species represents the typical morphology of a certain newly described taxon.
However, as you can see in the table, in some of old studies, even in original descriptions, there are missing records about type designation and type deposition in some genera of corallimorpharians.
As a result, we have literature, but there is no way to make certain that description with a material.

9. Primary Research Objective One. Revision of genera
- based on completed information
Objective Two. Validity of each genus
- valid?
- synonymous?
- new genus?
So, the completion of information at the genus level is very urgent. My research will focus on the completion as the first step, and the result of this study will be the revision of corallimorpharian genera.
Related to types, if necessary, neotype or lectotype will be designated followed by the International Nomenclatural Rule.
After that, the validity of each genus will be tested. Some genera may be valid. But may be some genera have very close character with other genera, and they will be synonymized. Or a new genus may be described.
These two primary studies are for the further study of this group.
As a conclusion, I would like to give you bigger picture of my research.

10. This research provides source for…
Relationship within the order
Relationship between orders
Other fields of biology
- conservation, biochemical and molecular biology
Scleractinia
(stony corals)
Actiniaria
(Sea anemones)
Corallimorpharia
Revision of genera, and testing validity can provide some source of my ultimate research.
The first further study is for the relationship within orders. Based on the different two group of morphology within corallimorpharians, the order Corallimorpharia may not be a monophyletic group.
More expanding study is the relationship between corallimorpharia and two closest orders, stony corals and sea anemones.
There are three three hypothesis for the relationship.
My animals are different but may be close to stony corals rather than with sea anemones.
OR, three orders may have evolved independently,
OR Corallimorpharia may not an order and a part of two other orders.
Also, in future, the result of my research will provide information about this taxon, for other fields of biology. For example, conservation research, or other applied study in biology.

11. Acknowledgment THANK YOU! My research is supported by
US NSF grant
in the program Partnerships to Enhance Expertise in Taxonomy
(PEET)
to Dr. Daphne Fautin
THANK YOU!