Calyptrophora distolos Cairns, 2018

Bribiesca-Contreras, Guadalupe, Dahlgren, Thomas G., Amon, Diva J., Cairns, Stephen, Drennan, Regan, Durden, Jennifer M., Eleaume, Marc P., Hosie, Andrew M., Kremenetskaia, Antonina, McQuaid, Kirsty, O'Hara, Timothy D., Rabone, Muriel, Simon-Lledo, Erik, Smith, Craig R., Watling, Les, Wiklund, Helena & Glover, Adrian G., 2022, Benthic megafauna of the western Clarion-Clipperton Zone, Pacific Ocean, ZooKeys 1113, pp. 1-110 : 1

Calyptrophora distolos Cairns, 2018

Fig. 18

Material.

Clarion-Clipperton Zone • 1 specimen; APEI 4; 7.2874°N, 149.8578°W; 4125 m deep; 04 Jun. 2018; Smith & Durden leg.; GenBank: ON400712 (COI), ON406604 (16S); USNM 1550968; Voucher: CCZ_131 .

Description.

Branching uniplanar, colony ~ 20.8 cm tall, with polyps perpendicular to the stem in in situ images (Fig. 18A ). Downward-oriented polyps, arranged parallel to the branch, mostly paired, but a few whorls with three to four polyps are present; polyps are ~ 2.7 mm tall and with an operculum longer than either of the body wall scales (Fig. 18B, C ).

Remarks.

Morphological characters are concordant with the description of Calyptrophora distolos ( Cairns 2018). In addition to the paired polyps mentioned in the species description, this specimen also presents a few whorls with three or four polyps (Fig. 18C ). Polyps are downward-oriented, therefore belonging to the wyvillei complex ( Cairns 2018). The species is most similar to C. persephone Cairns, 2015, which has been described for the UK-1 and BGR areas in the CCZ ( Cairns 2015). However, C. persephone is characterised as having polyps oriented upwards, therefore belonging to the japonica complex, and that are consistently arranged in whorls of three or four, with each basal scale bearing two prominent distal spines. Calyptrophora distolos was described from the Enigma Seamount, south of Guam, at 3737 m depth, and has also been recorded for American Samoa at 2994 m depth ( Cairns 2018). There are no genetic sequences available for other specimens of C. distolos , but the sequences generated here cluster with other species of the genus (Fig. 15 ). However, the genus was not recovered as monophyletic.

Ecology.

The specimen was found attached to a polymetallic crust on the slope of a seamount on APEI 4, at 4124 m depth.

Comparison with image-based catalogue.

A similar primnoid morphotype (i.e., Calyptrophora distolos sp. inc., ALC_016) was catalogued from seabed imagery (also collected on a seamount) in the eastern CCZ (e.g., Cuvelier et al. 2020), but not in abyssal areas of the Kiribati EEZ.

Order Pennatulacea Verrill, 1865

A total of 79 records of Pennatulacea occurring at> 3000 m depth in the CCZ have been recorded in OBIS, but none represent preserved specimens ( OBIS 2022). We recovered a single specimen, for which sequences of both 16S and COI genes were obtained, and which were included in the phylogenetic analysis of the Octocorallia (Fig. 15 ).

Suborder Sessiliflorae Kükenthal, 1915

Family Protoptilidae Kölliker, 1872

Figures

Figure 15. Rooted Bayesian phylogeny of Octocorallia. Concatenated (16 S, COI, mtMutS, NADH 2) median consensus BEAST tree with posterior probability (PP) and bootstrap (BS) values indicated. Only values of PP> 0.70 and BS> 50 are shown, with values of PP> 0.95 and BS> 90 indicated with a circle. Nodes not recovered on the RAxML tree are indicated with a hyphen. Sequences generated in this study are highlighted in violet.

Figure 18. Calyptrophora distolos Cairns, 2018. Specimen CCZ _ 132: A in situ image B whole colony C detail of polyps before preservation. Scale bars: 2 cm (A, B); 5 mm (C). Image attribution: Durden and Smith (A); Wiklund, Durden, Drennan, and McQuaid (B, C).