Calibelemnon francei, Williams, Gary C. & Alderslade, Philip, 2011

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 : 42-45

publication ID 10.5281/zenodo.200521


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scientific name

Calibelemnon francei

sp. nov.

Calibelemnon francei View in CoL sp. nov.

Figs. 7 View FIGURE 7. A C, 8C, 10

Material examined. HOLOTYPE: CAS 179455, Sta. No. ELE210-1, Bahamas—Bahama Escarpment, Eleuthera Island West, 25°40.1191’ N, 76° 46.2572’ W, 1969 m depth, 28 March 2009, coll. S.C. France; Bahamas Deep–Sea Coral Expedition, RV F.G. Walton Smith, ROV Global Explorer.

Diagnosis. Axis straight, autozooids arranged more-or-less in sub-alternate to opposite pairs along length of rachis with each pair separated by areas of bare rachis. Basal terminus of peduncle enlarged to form a plungershaped structure with a conical proximally protruding knob covering the end of the axis. No sclerites found in tissues sampled from several areas.

Description. The damaged holotype ( Fig. 7 View FIGURE 7. A C) is slender, straight, and 122 mm long. The approximately 0.5 mm diameter rachis occupies 90% of the colony and the axis is clearly observable beneath the thin coenenchyme. There are 25 autozooids, mostly 4–6 mm long, which are arranged biserially, opposite to alternately along the rachis in pairs. Areas of bare rachis between adjacent autozooids or pairs of autozooids vary from 4 to 12 mm long. The swollen and oblong basal regions of some autozooids contain several spherical ova, each approximately 0.25 mm in diameter. The siphonozooids are ovoid, approximately 0.2 mm long, and are arranged in two longitudinal rows along the bare areas of rachis. The peduncle represents approximately 10% of the total colony length and the proximal terminus, 5 mm long by 3–4 mm wide ( Figs. 7 View FIGURE 7. A C, 8C), is structurally similar to that of the other known species of rock-inhabiting pennatulaceans. No sclerites were found in numerous samples taken throughout the colony. The opaque autozooids of the wet-preserved colony are deep chocolate brown; the rachis is dark red, the peduncle tan, and the siphonozooids brown.

Etymology. We name this species for Scott C. France, University of Louisiana at Lafayette, for his discovery and collection of the holotype.

Distribution. This new species is presently known only from the type locality, Bahama Escarpment in the western Atlantic, 1969 m depth ( Fig. 10 View FIGURE 10 ).

Differential diagnosis. There are three nominal species of Calibelemnon , C. symmetricum Nutting, 1908 (the type species), C. indicum ( Thomson & Henderson, 1906) , and C. hertwigi ( Balss, 1909) , of which the last is considered invalid (Williams 1995: 117). Calibelemnon francei sp. nov. can be distinguished from the former two of these by its remarkably small peduncle, which occupies only 10% of the total colony length compared to 30%–46% for C. indicum and 47% for C. symmetricum . It also differs from C. symmetricum by having the siphonozooids arranged in two longitudinal rows compared to them being distributed all over the rachis in that species, except for a longitudinal band along the ventral and dorsal tracks.

Remarks. The holotype is the only known specimen of this species and does seem to have two characteristics that agree with the definition of the genus—more-or-less biserial polyps and bare regions of rachis between polyp pairs. However, since there are no other specimens for comparison at this point, it is possible these features may be at least partially due to specimen damage and/or poor preservation. If undamaged material is found that conforms to the description of Calibelemnon francei sp. nov., specialists may eventually agree that all known rock-inhabiting sea pens should be allocated to Anthoptilum . But without further evidence we assign the new species to Calibelemnon ..


California Academy of Sciences

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