Laetmonice stet. CCZ_060
|
publication ID |
https://dx.doi.org/10.3897/zookeys.1113.82172 |
|
persistent identifier |
https://treatment.plazi.org/id/48F3C09C-E045-5C58-9162-DB85853E9B6E |
|
treatment provided by |
|
|
scientific name |
Laetmonice stet. CCZ_060 |
| status |
|
Fig. 3 View Figure 3
Material.
Clarion-Clipperton Zone • 1 specimen; APEI 7; 4.8897°N, 141.75°W; 3096 m deep; 27 May. 2018; Smith & Durden leg.; GenBank: ON400687 View Materials (COI); NHMUK 2022.76; Voucher code: CCZ_060 GoogleMaps .
Description.
Single specimen (Fig. 3A View Figure 3 ). Body short, ovoid, flattened ventrally and somewhat arched dorsally. Specimen ~ 1 cm at widest point and 2 cm long, with 31 chaetigers. Dorsal felt not present. Specimen caked dorsally in dense layer of pale sediment (Fig. 3B, E View Figure 3 ), easily removed from dorsum but adhering to prostomium, parapodia, chaetae, and pygidium, obscuring respective features. Elytra 15 pairs, semi-translucent, smooth, and overlapping to cover dorsum (Fig. 3C View Figure 3 ). Dorsal cirri long, fine and tapering, extending beyond parapodia. Ventrum smooth. Ventral cirri, short, mostly broken off, not extending to base of neurochaetae. Parapodia biramous. Notochaetae include long, dark, brassy spines (Fig. 3E View Figure 3 ) with simple, tapered tips or with harpoon-shaped tips bearing four or five recurved fangs (Fig. 3D View Figure 3 ); both types of notochaetae with tuberculated shafts (Fig. 3G View Figure 3 ); neurochaetae include finer, shorter, paler chaetae with subdistal lateral spur and distal fringe of filamentous hairs (Fig. 3F View Figure 3 ), tips frequently broken off or covered in sediment.
Remarks.
The presence of harpoon-shaped notochaetae supports the placement of this specimen within the genus Laetmonice ( Fauchald 1977). Forms a monophyletic clade with other species of the genus Laetmonice based on COI sequences. Genetically distinct from Laetmonice stet. CCZ_060, the closest match is with Laetmonice filicornis Kinberg, 1856 (90.8% similarity). Laetmonice filicornis is described from shelf depths near Sweden in the North Atlantic.
Ecology.
This specimen was observed crawling on the sedimented seafloor on the seamount of APEI 7 at 3096 m depth.
Comparison with image-based catalogue.
No exactly identical Aphroditiformia 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 Laetmonice stet. CCZ_060 was added as a new morphotype (i.e., Laetmonice sp. indet., ANN_019) in the megafauna imagery catalogue. Only one other Aphroditiformia morphotype (i.e., Aphroditidae gen. indet., ANN_022; with much larger spines and no sediment coating), was catalogued from seabed imagery in the eastern CCZ, also found on a seamount. In vertically-facing seabed images, Aphroditiformia morphotypes could potentially be confused with plate-shaped Xenophyophore tests (e.g., Psamminidae ), particularly a dense layer of sediment is found coating specimens, as observed in Laetmonice stet. CCZ_060 (Fig. 3A View Figure 3 ).
Phylum Arthropoda von Siebold, 1848
Subphylum Crustacea Brünnich, 1772
Superclass Multicrustacea Regier, Shultz, Zwick, Hussey, Ball, Wetzer, Martin & Cunningham, 2010
Class Thecostraca Gruvel, 1905
Subclass Cirripedia Burmeister, 1834
Infraclass Thoracica Darwin, 1854
Superorder Thoracicalcarea Gale, 2015
Order Scalpellomorpha Buckeridge & Newman, 2006
Family Scalpellidae Pilsbry, 1907
To date, there is a single record at> 3,000 m depth for the order Scalpellomorpha in the CCZ ( OBIS 2022), but no collected material. Three specimens were collected during the DeepCCZ expedition; these belong to three different species from which only one was confidently assigned to a previously described species. Sequences for the COI and 18S genes were generated for the three specimens and included in a phylogenetic tree estimated from 18S and COI sequences (Fig. 4 View Figure 4 ).
Scalpellomorpha have been commonly found in image-based megafauna surveys across the north Pacific abyss, usually attached to sponge stalks or nodules. However, their classification beyond family level (e.g., Scalpellidae ) from seabed imagery is constrained by their generally small size; only large specimens (> 3 cm) which are rarely encountered can sometimes be classified to genus level from in situ images. Consequently, scalpellid specimens usually are collated into a single, generic morphotype (i.e., Scalpellidae gen. indet., ART_010) in image-based quantitative analyses.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.