Acropora fastigata
Nemenzo, 1967
Corallum caespitose; base creeping closely to substratum. Branches vertical at center, oblique to edge. Old branches stout, markedly tapering at narrow, conical apex; 15-20 mm across at base, up to 6 cm high; surface made irregular by numerous proliferous radials. Young branches cylindrical, appearing as consisting of tall axial corallite carrying few low nariform corallites at sides. Branches of all ages mixed up.
Axial corallites large, up to 4 mm wide, 3-4 mm exsert but appears more prominent because young radials around base tiny. Wall finely spongy, nonstriate, thick, thicker than calicinal diameter, evenly echinulate, edge rounded. Septa very thin; primaries reaching around radius midpoints, directives hardly distinguishable; secondaries about half as wide as primaries or less.
Radial corallites of unequal heights, unevenly distant – very tiny hemicotyloid around base of axial, gradually becoming prominent and wider downward; beyond 1.5 cm below apex, radials of various heights. Most are nariform or tubonariform with oblique calices, lower wall slightly thicker, more prominent than inner; calice elliptical, few facing sideward, even downward. Several tall tubulars, bearing buds mark older portion of branch, grading into branchlets, giving bristly appearance to branches. Septa very narrow, 2 complete cycles, directives seldom distinguishable. Smaller, subimmersed corallites on depressed areas between branches – some with very thin ring around calice; their septa similar to those in upper regions.
Intercalinical areas relatively dense – some have meshes wider than threads and echinules unevenly disposed; others have fine reticulation with echinules evenly disposed.
Remarks:This species doubtless belongs to the humilis group but for the very prominent, slender apices, with axial corallite cylindrical or slightly tapering; sides of branches bristly due to very tall bud-bearing radials into branchlets.
Type Specimen Location: 
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