Family Pectiniidae: (Gk. pectinis, comb).... probably relating to the comb-like appearance of the walls,
which are often tall, thin and striated. In general morphology, pectiniid colonies are usually laminar, composed of thin plates of
varying thickness. Corallites, which are visible to the naked eye, are highly visible and prominent, do not have definite walls
(but if present are only rudimentary, and are formed by the nonporous costate coenosteum of the laminae (Veron 1986).
There seems to be some variation in the strength of the corallum within and among species, depending on environmental
conditions. Most members of this family are usually found of reef slopes and off-reer floor.
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There are five extant genera (i.e. Echinophyllia, Echinomorpha, Oxypora, Mycedium and Pectinia) all found in PNG
waters. The family is characterized by thick fleshy, sometimes colorful, polyps which have a superficial resemblance to some
faviids and mussids.
Colonies of Mycedium elephantotus were observed to be thicker and sturdier on reefs where strong currents presominate,
and where tidally-induced upwelling events are common (i.e. daily phenomena). According to most sources, the polyps are expanded
only at night, when the animal presumably feeds. However, an interesting observation was made, where a juvenile colony of
Mycedium elephantotus was feeding during the day. The colony was situated in a hydrothermal vent, where temperatures
reached 42°C. |
Some members of the family Pectiniidae (131kB)
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Pectiniidae can be found in a variety of habitats, from shallow upper reef slopes to deeper fore-reef slopes, as well as from clear
offshore habitats to fringing reefs in turbid coastal waters. The general morphology of the corallum makes most pectiniids highly
efficient passive sediment rejectors. Their abundance, especially of Pectinia spp. in turbid coastal areas, may be directly
related to their sediment-rejection ability.
All pectiniidae studied thus far are hermaphroditic and spawn gametes. Echinophyllia aspera, E.orpheensis, Mycedium
elephantotus, Oxypora glabra, Pectinia alcicornis, P.lactuca, and P.paeonia have been observed to spawn during
mass-spawning events.
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All genera are only found in Indo-Pacific waters:------------------------------------------------------------------------------
Echinophyllia (Gk. echinos, hedgehog, spiny; phyllon, leaf):
Low-growing corals with irregular foliaceous or encrusting growth form. Center of corallum is attached and solid. Margins are free
and thinner. Colonies are brown, with the calices green or pink. Corallites which are scattered in a pattern of concentric rows,
are prominent and are often separated by a gap of several mm or more. Corallites may be 10-20mm in diameter and are generally
elevated several mm above the surface of the corallum (plocoid). Calices are roundish in cross section, and connected
with neighborung calices by numerous and exsert septa. Paliform lobes are usually present with elaborately worked
dentate costal margins. (8 known species).
Echinomorpha (Gk. echinos, hedgehog, spiny; morphus, ?):
There is only one species member of this family, E.nishihirai which predominantly occurs as a solitary individual which are
thin and delicate. Corallites of colonial individuals are very large. Skeletal characters include mussid-like septal teeth.
(1 known species).
Oxypora (Gk. ox, sharp; porous, pore):
Semi-encrusting with free-foliaceous margins. Brittle and fragile corallum, with a warty appearance; colonies are brown in color
with pink, green, or gray calice centers. Spider-like corallites are well separated and distinct, others are crowded and partially
joined together. The coenosteum is perforated with grooves. Calices are rounded to elliptical in shape (3-8mm in diameter)
and are superficially or slightly raised. Each calice houses 8-12 septo-costae that are thickened and exsert at the outer edge.
Costae and septa have sharp spines. (5 known species).
Mycedium (Gk. mykes, knobbed; -idion, diminutive suffix):
Foliaceous or semi-encrusting colonies that may measure 2m across. Edges tend to be delicate and easily broken; colonies are
brown with pink or greenish tinges and brightly colored green or red oral disks. Coralites are well spaced, crowded in places with
diameters ranging 5-15mm and inclied, facing outwards to the edge of the colony margins. Sometimes they protrude 3-4mm
from the corallum. Septa are numerous with sharp spines and continue as costae on perithecal areas. Costal margins are
spiny. (5 known species).
Pectinia (Gk. pectinis, comb):
Forms encrusting, foliaceous, or branching colonies with a distinct semi-meandrine arrangement of collines which form thin, delicate
convulated leaves (or even fluted walls) over the surface of the corallum (up to 5cm high and few mm wide). Calices are superficial
and lack true walls, circular and oval inappearance (2-10mm in diameter), are widely spaced and scattered over the coral surface.
Colony color is brown, or gray with green tints on top; top of the walls are pale. Margins of septa and septo-costae are finely and
irregularly serrated (9 known species).
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