Family Anthothelidae

Titanideum frauenfeldii (Kölliker, 1865)

Solanderia Frauenfeldii Kölliker 1865:141, pl. 19 figs 19-20,22.

Remarks. Titanideum frauenfeldii is a very common species occupying hardbottom habitats in the South Atlantic Bight. Generally the colonies are moderately branched (or unbranched if small), stiff, cylindrical, digitate branches reaching 8 mm in diameter. The calyces may be flush with the surface, slightly protruding, or slightly indented. They vary from yellow to deep red in color. The ring of boundary canals separating the cortex and medulla is indicative of this family and is generally very apparent when examining the branch in cross section. Also present is a layer of solenia, which divides the cortex into two layers, a thin, densely spiculated outer cortex and a thick, spongy inner cortex. The cortical sclerites consist of variable pink radiate bodies, and the medulla is filled with densely packed, colorless branching rods that are generally oriented longitudinally.
There are some colonies that have been examined (S2314, S2655, S2660) for this work that do not appear consistent with the typical T. frauenfeldii morphology. These colonies are not stiff, generally unbranched, and have protruding conical calyces. The width of the stems range from 2-4mm and the tips are somewhat inflated. Growing tips at both ends of some colonies suggests that they were unattached. The color of the colonies varies from pinkish orange to white. Spiculation of these colonies is consistent with the description of T. frauenfeldii in Bayer (1961) and distinguishes them from any other member of the western Atlantic Anthothelidae. Information on the nature of this morphological variation is not available, however all of the species examined for this work that display the variance were collected from 79-91 m, which is considerably deeper than some of the hardbottom habitats that the typical morphology of T. frauenfeldii occupies. This observation might suggest further investigation of the role of depth in the morphological differences exhibited by this species.
There are numerous lots of this species in the NMNH collections representing the shallow SAB.

Atlantic distribution: North Carolina to Cuba, north Gulf of Mexico, 13-293 m (Deichmann, 1936; Bayer, 1961; NMNH collections; SERTC collections).

Figure 1. Titanideum frauenfeldii whole colony (approximately 26 cm in height).

Figure 2. Titanideum frauenfeldii (in situ), showing expanded polyps.