Benthodytes cf. sanguinolenta Theel , 1882

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

Benthodytes cf. sanguinolenta Theel, 1882

Fig. 44

Material.

Clarion-Clipperton Zone • 1 specimen; APEI 1; 11.2953°N, 153.742°W; 5245 m deep; 09 Jun. 2018; Smith & Durden leg.; GenBank: ON400720 (COI); NHMUK 2022.70; Voucher code: CCZ_178 .

Description.

Single specimen (Fig. 44A ). Colouration of live specimen is light pink dorsally (Fig. 44B ), darker ventrally (Fig. 44C ). Tentacles 18, yellow, digitiform. Numerous dorsal papillae scattered on dorsal. Brim wide. Tube feet in double rows along the mid-ventral ambulacrum, ~ 30 pairs, yellowish. Ossicles not found.

Remarks.

The closest match for the COI sequence is a sequence from B. sanguinolenta (GenBank: HM196505.1; 93.54% similarity) from the Ross Sea, Antarctica. A genetic study revealed two separate clades within B. sanguinolenta ( O’Loughlin et al. 2011): (1) specimens from northwest Australia, and (2) Ross Sea. None of the samples included in O’Loughlin et al. (2011) are from the type locality (34.1167° S 73.9399°'W, off Chile, Pacific Ocean; 4000 m), but they identified at least two separate genetic species. The COI sequence of the specimen collected in the CCZ forms a third clade within the B. sanguinolenta species complex (Fig. 34 ). Genetic divergence (K2P distance) between the CCZ specimens and both NW Australia and Ross Sea clades is 10.1% and 7.3%, respectively, corresponding to values of intraspecific divergence in the group. In original description, Théel (1882) describes the body to be 6-7 × longer than wide, whereas the preserved specimen collected in the CCZ is only ~ 3 × longer than wide, but might be due to preservation as in in situ images it appears longer. However, the number of digitiform tentacles and appearance of small processes are concordant with the description of B. sanguinolenta . The sequence of Benthodytes cf. sanguinolenta from Glover et al. (2016b) does not form a clade with the CCZ specimen, with COI genetic distance being large (K2P 23%).

Ecology.

The specimen was found on the sedimented seafloor of an abyssal plain in APEI 1 at 5249 m depth.

Comparison with image-based catalogue.

No exactly similar Benthodytes sp. morphotypes have been so far catalogued from seabed imagery collected in the eastern CCZ or in abyssal areas of the Kiribati EEZ. Consequently, the in situ image of specimen CCZ_178 was catalogued as a new morphotype (i.e., Benthodytes sanguinolenta sp. inc., HOL_124).

Figures

Figure 34. Phylogenetic tree of the class Holothuroidea. Concatenated (12 S, 16 S, 18 S, 28 S, COI, and H 3) 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 44. Benthodytes cf. sanguinolenta Theel, 1882. Specimen CCZ _ 178: A in situ image B dorsal view of specimen before preservation C ventral view. Scale bars: 2 cm (A); 1 cm (B, C). Image attribution: Durden and Smith (A); Wiklund, Durden, Drennan, and McQuaid (B, C).