Dondersiidae, Simroth, 1893

Cobo, M. Carmen & Kocot, Kevin M., 2021, On the diversity of abyssal Dondersiidae (Mollusca: Aplacophora) with the description of a new genus, six new species, and a review of the family, Zootaxa 4933 (1), pp. 63-97 : 90

Dondersiidae sp. D

( Figure 8 , Table 2 )

Examined material. DZMB-HH-14021-17 (DZMB-Senckenberg Biozentrum Grindel und Zoologische Museum). Serial sections (eight slides) and sclerite preparations (two stubs, three slides). Brazil Basin. DIVA 3 Me 79/1, station 609 (area 4); 03º 57.54’S, 28º 03.07’W 5170.4 m depth .

Description. White, scaly animal (in 70 % ethanol) with the anterior end truncated and the posterior end pointed (2.1 mm long, 0.27, 0.25, 0.2 mm of width in the anterior and middle region respectively ( Figure 8 D ). Sclerites as scales inserted in a single layer in the thin cuticle (<15 μm): 1) Leaf-shaped scales ( Figure 8 D-1) that are the main type. These are broad, but narrow towards the apex, with a flat proximal end (64.25 to 79.95 μm in length, 27.95 to 28.16 μm in width). 2) Leaf-shaped scales with a flat proximal end ( Figure 8 D-3). These are the second most abundant variety; they are small (40 to 46.3 μm long, 22.5 to 23.6 μm wide) and more damaged (with longitudinal grooves). 3) Oval scales ( Figure 8 D-2), which are very small (25 μm long, 10 to 15 μm wide) and few in number, are considered a different variety because of their shape and size but could be leaf-shaped scales that have not yet developed. 4) Solid curved acicular sclerite ( Figure 8 D-4), which are concentrated in the dorsal region of the body (97 to 115.6 μm long, 3.6 to 4 μm wide in the middle region and 1.7 to 2 μm wide at the ends). This combination of sclerite types and the shape of the leaf-shaped scales are typical of Helluoherpia .

Figures

FIGURE 8. Habitus and sclerites of the undetermined specimens. A. Dondersiidae sp. A. A1. Leaf-shaped scales with a long and narrow acuminate end. A2. Oval leaf-shaped scales. A3, A4. Laminar scales B. Dondersiidae sp. B. B1. Leaf-shaped scales B2. Asymmetric leaf-shaped scales B3. Acicular sclerites. C. Dondersiidae sp. C. C1, C2. Lanceolate leaf-shape scales C3. Rounded leaf-shaped scales C4, C5. Laminar scales. C6. Oar-shaped scales. D. Dondersiidae sp. D. D1. Leaf-shaped scales. D2. Leaf-shaped scales with a flat proximal end D3. Oval scales. D4. Solid, curved acicular sclerites.