Angursa lanceolata Renaud-Mornant, 1981

Fujimoto, Shinta & Hansen, Jesper Guldberg, 2019, Revision of Angursa (Arthrotardigrada: Styraconyxidae) with the description of a new species from Japan, European Journal of Taxonomy 510, pp. 1-19 : 7-8

Angursa lanceolata Renaud-Mornant, 1981

Fig. 4

Emended diagnosis

Angursa with bulbous primary clavae terminating in apices shorter than lateral cirri; pedestals of primary clavae and lateral cirri present; flat secondary clavae present; morphology of tertiary clavae unknown; lance-like cirri E; Leg I sensory organs present; legs II and III sensory organs absent; leg IV sensory organs each as elongate papilla with short apical spine; anal papillae absent.

Material examined

Paratype

ATLANTIC OCEAN • 1 adult; mounted with the dried out holotype; Dinet leg.; AE128.

Remarks

The primary clavae were described as leaf-shaped by Renaud-Mornant (1981), but the primary clavae of the paratype we observed were bulbous papillae (8 μm long, 6 μm in diameter) with blunt apices (the apex were only recognised in one of the clavae) ( Fig. 4A ). Their neighbouring sensory organs, the lateral cirri (17 μm) ( Fig. 4A ), were apparently longer than reported in the original description (11 μm) ( Renaud-Mornant 1981). As it was drawn in the original description, the pedestals that support the primary clavae and the lateral cirri were apparent ( Fig. 4A ). We recognised the flat secondary clavae ( Fig. 4A ) which had already been mentioned as slightly hollow formations by Renaud-Mornant (1981), but their contours were difficult to observe. The presence and morphology of the tertiary clavae could not be revealed in this study. The characteristic cirri E ( Fig. 4B ) were confirmed, but their proportion seem slightly different that the drawing provided by Renaud-Mornant (1981). We recognised the short, apical spines of the leg IV sensory organs ( Fig. 4B ) which were overlooked in the original description ( Renaud-Mornant 1981). Other measurements of the paratype are as follows: body length. 136 μm; median cirrus, 3 μm; internal cirrus, 6 μm; external cirrus, 6 μm; cirrus E, 11 μm; leg I sensory organ, 6 μm; leg IV sensory organ, 5 μm.

Angursa lanceolata closely resembles A. lingua by the bulbous primary clavae shorter than the lateral cirri, the apparent pedestals that support these two sensory organs, and the elongate leg IV sensory organs with apical spines ( Renaud-Mornant 1981; Bussau 1992). However, these two species are easily distinguished from each other by the longer cephalic cirri and cirri E in A. lingua (median cirrus, 10 μm; internal cirrus, 9 μm; external cirrus 13 μm; lateral cirrus 28 μm; cirrus E, 20 μm (body length, 145 μm)) and by the lance-shaped cirri E in A. lanceolata versus tongue-shaped cirri E in A. lingua (Renaud- Mornant 1981; Bussau 1992).

Figures

Fig. 4. Micrographs of Angursa lanceolata Renaud-Mornant, 1981 paratype. A. Cephalic region. B. Caudal region with leg IV sensory organ terminating in short, apical spine (white arrowheads).