Anthoptilum decipiens Thomson & Henderson, 1906

Williams, Gary C. & Alderslade, Philip, 2011, Three new species of pennatulacean octocorals with the ability to attach to rocky substrata (Cnidaria: Anthozoa: Pennatulacea), Zootaxa 3001, pp. 33-48 : 36

Anthoptilum decipiens Thomson & Henderson, 1906

( Fig. 10 )

Anthoptilum decipiens Thomson & Henderson, 1906: 109 .

Remarks. Part of Thomson and Henderson’s (1906: 109) inadequately illustrated description of this species, follows. “The stalk is short and conical; it expands gradually from its junction with the rachis downwards, and has a large knob in the centre of the base. The base thus resembles a “tam o’ shanter”; or, to put it another way, the stalk ends in a large knob, but before reaching the knob it expands into a large collar-like fold …. The most noteworthy features of this species are: …. 3. The shape of the basal expansion with its knob-like termination into which the end of the axis extends. …. Locality: …. 7° 55’ N., 81° 47’ E: 506 fathoms.”

As a result of this detailed account of the proximal end of the peduncle, we regard A. decipiens as a rock-inhabiting sea pen. Other aspects of the description (elongate colony 720 mm in length, ratio of colony length to rachis diameter 180:1, siphonozooid distribution, minute rod-like sclerites in the peduncle that may form star-shaped groups) indicate that this is a fourth species of this type of sea pen, despite Kükenthal (1915) listing it as a synonym of A. grandiflorum . We are, however, unable to confirm this, as the specimen is probably in the Indian Museum in Kolkata (where the bulk of the samples from the Investigator expedition are stored), and we have never been able to obtain information or loans from this institution. Thomson and Henderson (1906) did not designate type specimens, but some of their specimens labeled as holotypes, or as parts of holotypes, are in the Natural History Museum, London—unfortunately A. decipiens is not among them.

Figures

FIGURE 10. World map showing known geographic locations of rock-inhabiting sea pens: = Anthoptilum gowlettholmesae sp. nov.; = Anthoptilum lithophilum sp. nov.; = Calibelemnon francei sp. nov.; + = Anthoptilum decipiens; * = taxa indeterminate; from specimen CAS 179456 (Hawai’i) and / or underwater images (Hawai’i and New Zealand).