Catherinum cf. albatrossianum (Pilsbry, 1907)

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

Catherinum cf. albatrossianum (Pilsbry, 1907)

Fig. 6

Material.

Clarion-Clipperton Zone • 1 specimen; APEI 7; 5.0442°N, 141.8165°W; 4875 m deep; 28 May. 2018; Smith & Durden leg.; GenBank: ON400697 (COI), ON406623 (18S); WAM C74109 ; Voucher code: CCZ_073 .

Description.

Single specimen 21 mm long, attached to glass sponge stalk (Fig. 5A ; upper, green arrow). Capitulum elongated, white, ~ 2 × as long as wide (L = 16 mm, W = 8 mm); widest in the middle, tapering towards summit and base; short peduncle (4 mm) with small scales (Fig. 6A, B ). Fourteen capitular plates fully calcified, showing growth lines, and separated by very narrow chitinous spaces. Carina is strongly arched in the distal half, tapering proximally, with flat roof and apical umbo. Tergum is almost a right triangle, longer than wide, with slightly convex occludent margin. Scutum is more than twice as wide as long, with arcuate occludent margin, with a distal indent on the lateral margin for the reception of the apex of the upper latus; baso-lateral margin rounded and next to the infra-median latus. Upper latus is pentagonal; with apical umbo projecting into notch on the scutum; scutal margin in concave; very short basal margin and carinolateral margin longer than carinal margin. Rostrolatus has an umbo projecting from the rostral margin. Rostrum minute. Large carinolatus, ~ 2 × as long as wide, umbo sub-basal, abutting base of carina, apex slightly extending approximately one fifth of the carina. Inframedian latus is> 2 × as long as the widest section, widest distally and with rostral and carinal margins concave, with umbo sub-basal.

Remarks.

Morphological characters are in accordance with the description of C. albatrossianum . The 18S sequence matches three genera within the subfamily Arcoscalpellinae Zevina, 1978, while the closest match (85% similarity) for the COI sequence is to another species of Catherinum . Like, C. cf. novaezelandiae it differs morphologically from C. tortilum , reported from the CCZ by Poltarukha and Mel’Nik (2012), in the form of the inframedian latus. The type locality of C. albatrossianum is off Cape Hatteras, in the northwest Atlantic, at ~ 3740 m depth, but it has been reported for the North Atlantic, Gulf of Mexico, and Indian Ocean between 760 and 4180 m depth ( Zevina and Poltarukha 2014). The original description states that the species lacks a rostrum, however, a minute rostrum is present in the specimen examined herein. This in addition to the documented range of this species is the reason for the use of cf. in the identification.

Ecology.

Specimen was collected in a muddy abyssal area of APEI 7, at 4874 m depth. It was attached to a glass sponge stalk (Fig. 5A ; upper, green arrow), along with another barnacle ( Trianguloscalpellum gigas , specimen CCZ_074; lower, yellow arrow), and an anemone ( Metridioidea stet. CCZ_072; specimen CCZ_072). It had hydrozoans and two serpulid polychaetes attached to it.

Comparison with image-based catalogue.

A very similar morphotype ( Catherinum sp. indet., ART_032) has been encountered (e.g., large specimens> 3 cm in length) in seabed image surveys conducted across the eastern CCZ and in abyssal areas of the Kiribati EEZ.

Figures

Figure 5. Trianguloscalpellum gigas (Hoek, 1883). Specimen CCZ _ 074: A in situ photograph, attached to a glass sponge stalk B left C and right lateral views. Scale bars: 5 cm (A); 1 mm (B, C). Image attribution: Durden and Smith (A), Hosie (B, C). Arrows indicate position of T. gigas (specimen CCZ _ 074; lower, yellow) and Catherinum cf. albatrossianum (specimen CCZ _ 073; upper, green).

Figure 6. Catherinum cf. albatrossianum (Pilsbry, 1907). Specimen CCZ _ 073: A left B right lateral views. Scale bars: 2 mm. Image attribution: Hosie (A, B).