Parent document
Non-Scleractinian Cnidaria:

Even though scleractinian corals are the primary builders of present-day coral reefs, skeletal meterial of other groups, both plant and animal, is incorporated into the construction of the reef matrix. On reefs of PNG, the octocorals are a consequential component of the coral reef community in terms of abundance, biomass, as well as diversity. The contribution of this group to the reef matrix consists of calcite sclerites (e.g. Alcyonacea, soft corals), and branched (e.g. Gorgonacea - sea fans), or unbranched (e.g. Pennatulaceae, sea pens). Among the Alcyonacea, there are two conspicious groups that in regard to their size contribute substantially to the calcium carbonate (CaCO3) deposition on PNG reefs.

Class Anthozoa - subclass Octocorallia (polyps with 8 tentacles) - order Helioporacea Family Helioporidae (Blue Coral; Gk. helios, sun; L. porus, pore): possibly relating to the arrangement to the pores, with the small ones grouped around the larger ones. The most prominent member in the genus Heliopora is the species H.coerulea , (formely known as Millepora coerulea). Colonies grow in intertidal reef flats and consists of encrusting or semi-massive base from which arise a mass of branches or lobes. They are only a few cm in height and width, have blunt ends and are usually slightly flattened laterally. Corallum is laminate or encrusting and lacks branches; they are tall, wholly branched colonies. The polyps (anthozoids) are less than 0.5mm in diameter. Heliopora's skeleton consists of fibro-crystalline aragonite and is permanently colored in blue.
PRESENT DISTRIBUTION: Indo-Pacific region and the Red Sea.
FOSSIL RECORD: Cretaceous.
NUMBER OF EXTANT SPECIES: 1 known species: Heliopora coerulea .


Some members of the family Helioporidae and Tubiporidae (167kB)

Class Anthozoa - subclass Octocorallia (polyps with 8 tentacles) - order Alcyonacea Family Tubiporidae (Organpipe Coral; L. tubus, tube; porus, pore): possibly relating to the small tubes in which the polyps are situated. The most consicious member in the genus Tubipora is the species T.musica. Colony forms rounded heads that may reach 1m or more in diameter. Each polyps has a ring of 8 feather-like tentacles, several mm long. The tentacles are green bluish, gray, white, or brown in color. Tubipora's skeleton is bright red in color. Mass of vertical tubes bound together by horizontal platforms resemble the arrangement of pipes of an organ.
PRESENT DISTRIBUTION: restricted to the wider Indo-Pacific region.
FOSSIL RECORD: Pleistocene.
NUMBER OF EXTANT SPECIES: 1 known species: Tubipora musica.

The fire and rose corals do not belong to the anthozoan but in the hydrozoan class. They represent a group of cnidarians with characteristic "alternation of generations" between sessil hydroid and planktonic medusoid forms. Hydrozoan polyps, although cnidarians, lack mesenterial partitions and their endoderm lacks nematocysts.

Class Hydrozoa - order Anthoathecata - suborder Capitata Family Milleporidae (Firecoral; L. mille, thousand; porus, pore): refers to the numerous small pores that cover the surface of the coral.
Firecorals are a group of colonial hydrozoans that produce sometimes massive, but brittle, calcareous skeletons. The genus Millepora is found on reefs throughout the tropical seas, where it inflicts painful burning stings to the unwary visitor with its minute multiple club tentacles.
Millepora forms branch, platelike, massive and incrusting colonies. The branches are rounded or flattened; the plates are upright. Other forms are box-like structures. Millepora is white, yellow, or brown in color. They appear smooth and structureless. Microscopic polyps (0.1mm in diameter) are in the skeleton; the larger ones are called gastropores housing feeding polyps; the smaller ones the smaller defensive polyps are the dactylopores.
FOSSIL RECORD: none (?).
NUMBER OF EXTANT SPECIES: 14 known species:
M.boschmai, M.brasiliensis, M.complanata, M.dichotoma, M.exaesa, M.foveolata, M.intricata, M.latifolia, M.nitida, M.platyphylla, M.squarrosa, M.striata, M.tenella, M.tenera.


Some members of the family Milleporidae and Stylasteridae (154kB)

Class Hydrozoa - order Anthoathecata - suborder Filifera Family Stylasteridae (Rose corals; Gk. stylos, style; aster, star): the pillar-like structure in the center of each gastropore.
The rose coral order is quite large and are distributed from the Arctic through the tropics to the Antarctic, where they occupy a veriety of habitats ranging from shallow, subtidal environments to depths greater 500m. Unlike the order Milleporina, the Stylasterina do not have a free medusa stage, and gametes are formed on aborted medusae in sporosacs. Dystichopora and Stylaster are the dominant genera among this family and are present in the PNG archipelago with several species (Erina, Stenohelia, Crypthelia, and Conopora are represented to a lesser extent). Their characteristic feature is the presence of cyclostomes, which are groups of dactylozooids and gastrozooids.
All members have fragile, branched colonies that are no more than 10cm in hight; the branches are oriented in one plane and the colonies are fan-like in shape. They are usually pink, purple, red, or white. In the skeleton there are larger gastropores (about 0.1mm in diameter) and have a stylus in the center.
PRESENT DISTRIBUTION: throughout the Indo-Pacific and Atlantic.