Species can be subdivided into three groups: species with nearly uniform polypar spines, species with slightly irregular polypar spines and normal hypostomal spines and species with slightly irregular polypar spines and reduced hypostomal spines.[2] Comparing four members of the genus, as described by Opresko, Aphanipathes sarothamnoides, Aphanipathes salix, Aphanipathes verticillata, and Aphanipathes pedata all exhibit bushy, irregular branching corallum with mostly straight, elongated, upward branches.[2]
Members of this genus tend to have uniserially arranged branches and branchlets, except for A. salix.[2] A. columbiana colonies take a fan-shape that exhibits 9th order and greater branching with colonies growing in height usually less than 12 cm, but as high as 25 cm.[2] Branchlets are ≤0.15mm in diameter, have smooth, needle-like spines usually 25mm tall or shorter and spaced 0.18-0.31 mm apart; polyps are spaced 0.27-0.36mm apart and are 0.55-0.65mm in transverse diameter.[2] Polyps living on branchlets grow on one side, in rows of 9-10 per cm.[2] A. columbiana colonies resemble those of Antipathes expansa, but expansa has spines which are more uniform in size.[2] Compared to two common fan-shaped coral species also in the western Atlantic: Antipathes atlantica and Antipathes gracilis, Aphanipathes colombiana has long, smooth spines, not small (0.1mm) triangular ones.[2]
Aphanipathes thyoides, a Caribbean species has similar spines and a similar branching shape, but unlike A. columbiana, its hypostomal spines are smaller or not present.[2] Aphanipathes verticillata is a morphologically plastic species with large colonies branched to the 12th or greater order, with compressed conical spines covered in small conical tubercles, longitudinally arranged in rows. Polypar spines can be as long as 0.3 mm, and abpolypar spines 0.09-0.15 mm. Spines in rows are spaced 0.28-0.36 mm apart usually, but not more than 0.5mm. A. verticillata polyps are typically 1.2-1.5 mm in transverse diameter and are spaced 0.3-0.4 mm apart in single rows on branchlets. Colonies collected in Hawaii range in height from 0.25-1.5m tall.[2] Aphanipathes sarothamnoides has 5-10 cm long branchlets, spaced 1.5-2.5cm apart with 0.2mm long spines,[6] with tubercles covering the top third or half of spines at an average density of 2.3/1000μm2.[2] A. verticillata mauiensis and A. verticillata verticillata (found in Japan) are different only in tubercle density.[2] The Hawaiian subspecies exhibits tubercle density of 2.4/1000μm2 and the Okinawa subspecies exhibits tubercle density of 2.9/1000μm2.[2] Aphanipathes salix has 2-3 cm long branchlets, spaced 0.3-2 cm apart, with 0.22 mm tall polypar and 0.13 mm abpolypar spines.[6] A. salix has few spine tubercles, mostly near the apex with an average density of 2.2/1000μm2.