Scleractinian Coral Family, Dendrophylliidae

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Family Dendrophylliidae: (Gk. dendron, tree; Gk. phyllon, leaf).... presumably relating to the branched, tree-like growth form of some species. Colonies are solitary or colonial, mostly azooxanthellate, thus non-reefbuilding. Corallites are prominent and well separated; their walls are very porous and are usually composed of a coenosteum. The septa are fused in a distinctive pattern (Pourtalès plan, most obvious in immature corallites); 4 septal cycles in which the three primary cycles stand free, while the 4th is curved over the smaller 3rd cycle and merges with the 4th of the next cycle).
This is an essentially azooxanthellate family with distinctly different Cretaceous and Cenozoic genera. The zooxanthellate genera (containing endosymbionts) include Turbinaria, Rhizopsammia, Duncanopsammia, Balanophyllia, and Heteropsammia) are very dissimilar. Duncanopsammia is morphologically much closer to azooxanthellate relatives. Turbinaria is the only real reef-building genus. The most abundant reef-associated azooxanthellate genera are Denrophyllia, Balanophyllia, and Tubastraea. These groups, especially Tubastrea, can be locally a dominant group, and in some instances the term ahermatypic (i.e. non reef-building) is not justified.	Some members of the family Dendrophylliidae (130kB)
For example, Tubastrea micrantha (forma Dendrophyllia micrantha) forms dense aggregations on current-swept reefs, where the colonies can be up to 1.5m in hight. Since these genera are azooxanthellate, they do not require sunlight to survive and are thus able to occupy a wide range of habitats. While Tubastrea aurea is found mainly in clear-water habitats, usually seaward reef slopes and drop-offs, Tubastrea micrantha has been found in very turbid, but current-swept environments, where it grows in profusions. It has frequently been stated that T.micrantha feeds only at night, since polyps are withdrawn during the day. However, it seems that polyp expansion in this and some other species can be induced by currents above a certain velocity. The majority of species in the family Denrophylliidae (e.g. Turbinaria mesenterina) seem to be gonochoric brooders. However, Tubastrea coccinea was reported to be a hermaprodite. (Harrison and Wallace, 1990). Not much is known about the other genera, but most likely T.aurea is a gonochoric brooder as well (Fadlallah, 1983).
Key to the family Dendrophylliidae Colony attached to substrate Colony with fronds or encrusting: Genus *Turbinaria* Colony composed of branches Branches subdivide: Genus *Duncanopsammmia* Branches do not subdivide: Genus *Balanophyllia* Colony not attached to substrate: Genus *Heteropsammia*
Zooxanthellate genera are restricted to the Indo-Pacific and Mediterranean region, while azooxanthellates are found worldwide: Indo-Pacific genera: ---------------------------------------------------------------------------------------------------------- Turbinaria (L. turbinatus, cone-shaped; -aria, suffix denoting resemblance): On both western and eastern Australian coasts, and to a lesser extent in Japan, Turbinaria species have distinctive distribution patterns, most species being more abundant, and forming larger colonies in non-reef habitats of high-latitude locations. In general, there are greater similarities between coralla from high-latitude locations on the eastern and western Australian coasts than there are between high- and low-latitude locations on the same coast. Most Turbinaria species exhibit very great environment-correlated variation and lack conservative skeletal characters, making some species especially difficult to separate. This genus is by far, the most species rich, with approximately 11 species, while the most common, and the most widely distributed members are Turbinaria frondens, T.peltata, T.mesenterina, and T.reniformis. The representatives of the genus Turbinaria are easily recognizable. However, many species exhibit environmentally controlled phentotypic plasticity to such an extent that species separation can become very difficult. T.mesenterina can grow in very turbid reef flats while forming large cabbage-like colonies. Turbinaria is an important reef-building species in PNG, often found to dominate non-reef substrates, such as old volcanic rocks and fluvial sediments. T.frondens formes large colonies and is very abundant on the turbid inner reefs. The shallower parts of the reef slopes are often covered by monospecific stands extending beyond 100m² of T.mesenterina, whose foliaceous plates are a significant component of reef sediments. Colonies often form vase-shaped convolutions or spreading leaf-like fronds, fans, or folds. In other cases layers of lobed plates produce massive irregular heads; only T.heronensis is branched. Colonies are usually about 20-50cm in diameter but may be considerably larger. The corallum as a whole is generally brownish, but the polyps, tentacles, may be more brightly yellow or white and the peristome greenish. Coenosteum is smooth with the skeleton being spongy and porous. Tentacles are (partly) extended during the day and have a flower-like appearance. Rounded corallites are separated from each other and distinct and may be present on both sides of the fronds (bifacial) or unifacial in flatter fronds and protrude 1-15mm in the form of a truncated cone (phaceloid). Corallites are usually 1.5-3mm (sometimes 5mm) in diameter with wide walls and narrow fossa. Insert septa are visible, with adult forms displaying a reduced septal cycle. A columella is well developed. Occur in deeper or silty locations. PRESENT DISTRIBUTION: Red Sea and western Indian Ocean to southern Pacific. GENERAL ABUNDANCE: very common, very conspicuous. FOSSIL RECORD: Oligocene of the Caribbean, Miocene ol the Tethys. NUMBER OF EXTANT SPECIES: 11 known species. Duncanopsammia (?. ?, ?; Gk. psammon, sand): D.axifuga, as the only member of this genus, is a deep-water species has rerely been recorded as most surveys are generally restricted to shallow-water habitats. Thus, this genus, more than any other genus, blends zooxanthellate with non-zooxanthellate characters. Based on corallite morphology alone, D.axifuga would fit comfortably in the azooxanthellate genus Balanophyllia, indicating a Cenozoic origin from azooxanthellate ancestors independently of other Dendrophylliidae. Colonies like D.axifuga consist of long tubular corallites as diverging branches. This rare genus is limited to the central to eastern pacific areas. PRESENT DISTRIBUTION: central Indo-Pacific. GENERAL ABUNDANCE: uncommon, very conspicuous. FOSSIL RECORD: Miocene (?) of the Pacific. NUMBER OF EXTANT SPECIES: One. 1 known species. Rhizopsammia (Gk, rhiza, root; psammon, sand) PRESENT DISTRIBUTION:. GENERAL ABUNDANCE: . FOSSIL RECORD: . NUMBER OF EXTANT SPECIES: several unverified species. Balanophyllia (Gk. balanos, acorn; phyllon, leaf) Solitary corals that are cylindrical to trochoid in shape. Corallites are about 10-15mm tall and about 10mm wide at the top. They are brilliant orange or red in color. Fine ridges are visible beneath the living outer theca. Septa are numerous and drop steeply to a well developed spongy columella. Perforated septa are arranged in cycles (Pourtalès plan) with their margins being smooth or granular, occasionally weakly dentate. Costal margins have small teeth. The skeleton is porous and perforated. PRESENT DISTRIBUTION: Mediterranean and Indo-Pacific GENERAL ABUNDANCE: sometimes common. FOSSIL RECORD: Miocene of the Thetys (doubtful record). NUMBER OF EXTANT SPECIES: 2 known species. Heteropsammia (Gk. heteros, unlike; psammon, sand): Heteropsammia so far has not been considered an important reef building coral. Corals are free-living, with a flat or keeled base. The pale gray, orange-brown, or greenish colony may be up to 25mm in diameter with well developed septa. Colonies usually house up to 5 corallites. The columella is broad, compact and deeply seated. Coenosteum is porous Commensal relationship with peanut worms (the sipunculid Aspidosiphon corallicola) and endolithic mussels (Lithophaga lessepsiana or H.cochlea ). Species occur on the dandy off-reef areas. PRESENT DISTRIBUTION: Red Sea and western Indian Ocean to western Pacific. GENERAL ABUNDANCE: uncommon, occurs on inter-reef sand flats. FOSSIL RECORD: Oligocene of the Tethys. NUMBER OF EXTANT SPECIES: 2 known species. Circum-tropical genera: ------------------------------------------------------------------------------------------------------- Tubastrea (L. tubus, tube; Gk. aster, star): This azooxanthellate coral (lacks photosynthetic symbionts) forms low-growing, tufted clumps of corallites that arise from a common base; some Tubastrea colonies are taller and tree-like. They are red, brilliant orange or dark green in color. Most cryptic reef habitats as well as underhangs and cave walls are often densely covered by Tubastrea aurea and Tubastrea diaphana. Polyps are sometimes partially extended during the day, and at night the corallum is hidden by a ring of bright yellow tentacles. The rest of the polyp is orange or red in color. Corallites are cylindrical or tubinate, with a diameter across the top of about 5 to 15mm. They are well separated (except newly budded ones) and distinct; intervening perithecal areas appear smooth or faintly ridged. Living tissues are fleshy and obscure the smaller septa (smooth to the touch), but the major ones are just visible. Septa are numerous and arranged in cycles. In young calices the inner ends of smaller septa curve and unite with their neighbors (Pourtalès plan), but in mature calices they are free and normal. Septal margins are smooth or finely and irregularly dentate. Costae are present as low ridges. The skeleton is porous. Occurs in clumps on the sides of reef patches, in caves, and in underhangs. PRESENT DISTRIBUTION: Central Indo-Pacific. GENERAL ABUNDANCE: locally very common. FOSSIL RECORD: . NUMBER OF EXTANT SPECIES: 2 known species. Dendrophyllia (Gk. dendron, tree; Gk. phyllon, leaf): This azooxanthellate coral can only be separated from Tubastrea by skeletal features, where the secondary septa are joined into a wishbone formation. The GBR host only one species (D.gracilis). PRESENT DISTRIBUTION: . GENERAL ABUNDANCE: . FOSSIL RECORD: . NUMBER OF EXTANT SPECIES: 1 known species.