Pliciloricus undetermined
Creators: name: Sørensen, Martin V.
name: Herranz, Maria
name: Grzelak, Katarzyna
name: Shimabukuro, Mauricio
name: Kristensen, Reinhardt M.
name: Zeppilli, Daniela
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Loricifera
Nanaloricida
Pliciloricidae
Pliciloricus
Pliciloricus undetermined

description: Pliciloricus sp.
Figs 9, 10A
Material examined
CHILE • 1 Higgins larva; abyssal plain, on the west side of the Atacama Trench; st. 7; 22°56.22ʹ S, 71°37.08ʹ W; depth 5500 m; 20 Mar. 2018; R / V Sonne SO261; deep-sea mud; mounted for LM in Fluoromount G on HS slide; NHMD 1177415 • 2 Higgins larvae; continental slope off Iquique, and near the Atacama Trench; st. 9; 20°19.97ʹ S, 70°58.70ʹ W; depth 4050 m; 28 Mar. 2018; R / V Sonne SO261; deep-sea mud; mounted for SEM; see also Table 1 and Fig. 1; personal reference collection of MVS.
Short description of Higgins larvae
The single larva mounted for LM has its head retracted and contains another stage that appears to be a postlarva (Fig. 10A). The contracted trunk length is 224 µm and maximum width is 160 µm, measured on the anterior part of the abdomen. The thorax region has six transverse folds, and the abdomen has eleven longitudinal folds on each side, suggesting the presence of 22 plicae. Anterior setae are thin, simple and unbranched (anterolateral seta length =30 µm; anteroventral seta length = 45 µm). Posterodorsal (length =47 µm) and posterolateral (length =38 µm) setae have the same simple appearance as the anterior ones, whereas the terminal setae (length =34 µm) are slightly thicker and appear more rigid. Toes are slender and long (length= 118 µm), and divided into a thicker proximal part (length =83 µm) that narrows abruptly into a thinner, distal end-piece (length =35 µm).
Specimens mounted for SEM of what is assumed to be the same species have protruded mouth cones and introverts (Fig. 9A). The mouth cone has six oral styles surrounded by six oral teeth (Fig. 9B–C). A short seta is present in midventral position on the mouth cone (Fig. 9C–D). The introvert has five rows of scalids, with eight clavoscalids in the first row. Each clavoscalid is composed of a short basis, two broad and flattened mid-pieces, and a short, thin tip (Fig. 9A, E). Row 2 has 10 scalids, composed of a laterally flattened proximal part and a sickle-shaped end-piece. The exact number of scalids in Rows 3 and 4 could not be determined, but in both rows the scalids are composed of two, relatively uniform units. Scalids of Row 5 are shorter, and consist of a proximal plate with a short, flexible distal appendage (Fig. 9E). All scalids carry long, but extremely thin, undulating hairs.
The thorax region is partly contracted and difficult to examine, but it appears to have four or five transverse folds. Likewise, it was not possible to establish the exact number of plicae in the slender abdomen, but there seems to be around 20–22. The abdominal cuticle, as well as the cuticle of the toes, has a fine honeycomb ornamentation on their surface (Fig. 9F). Anterior setae were difficult to observe, but three pairs of posterior setae with similar morphology as those in the LM specimen are present (Fig. 9G–H).
description: Published as part of Sørensen, Martin V., Herranz, Maria, Grzelak, Katarzyna, Shimabukuro, Mauricio, Kristensen, Reinhardt M. & Zeppilli, Daniela, 2023, Living on the edge - first survey of loriciferans along the Atacama Trench, pp. 162-187 in European Journal of Taxonomy 879 (1) on pages 176-178, DOI: 10.5852/ejt.2023.879.2169, http://zenodo.org/record/8155359