Certesella larai Bobrov & Duckert & Mitchell 2021, sp. nov.
Creators: name: Bobrov, Anatoly
name: Duckert, Clément
name: Mitchell, Edward A. D.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Protozoa
Amoebozoa
Lobosa
Arcellinida
Nebelidae
Certesella
Certesella larai

description: Certesella larai sp. nov. (Fig. 1–7, Sup. Fig. 1; Table 3)
Description: Shell elongated pear-shaped (Figs. 1, 2, 4 & Sup. Fig. 1), compressed with two large, rounded to irregular-elongated elliptical pores clearly visible in broad view, connected by tubes. No visible lateral pore. Punctuations and inner teeth on the neck usually absent but visible in some specimens (Fig. 3). In broad view shell outline oval elongated at the fundus (aboral end of the shell), then narrowing slightly until a bulge near the area of the two large pores where the sides are approximately parallel, and narrowing again at the base of the neck. Neck relatively short with a slight bulge and then again approximately parallel near the aperture (Figs. 1, 2 & 4). Shell colourless, covered with oval plates of different sizes and shapes (Fig. 4), most likely recycled idiosomes from euglyphid testate amoebae. Pores surrounded by smaller recycled idiosomes than the main body (Fig. 4). Pseudostome rim smooth and somewhat wavy, lip 2–2.5 µm thick (Figs. 2–4).
Measurements: Shell length: 135.8–153.4 µm, shell breadth: 56.8–68.2 µm, shell depth ca. 50 µm, aperture maximum dimension: 24.0–29.8 µm, distance from the fundus to the pores: 73.0–92.3 µm, distance from the fundus to the base (narrowest point) of the neck: 104.6– 125.0, distance between the pores: 22.8–34.1 µm, width of the neck at its narrowest point – 18.5–29.5 µm, pore length – 5.1–12.8 µm, pore width – 3.0–6.4 µm, shell length/breadth ratio 2.03–2.58 (Table 3). The variability of morphological characteristics is generally low (e.g. <6% for characters 1–6 Table 3), and only somewhat higher for the smallest dimensions for which the accuracy of measurements is lower.
Type locality and habitat: Parque Nacional Alerce Costero, Los Ríos Region, Chile, Small Sphagnum peatland, with Fitzroya trees. In Sphagnum. Coordinates: –40.171975°; –73.491841°, elevation 1028 m. a.s.l., EM-1453 / Chi 2. Locality of the paratype specimen: Ebano Verde National Park, Dominican Republic. Broadleaf forest litter Forest approximatively three quarters of way up from the river to the ridge. Elevation 1423 m. above sea level. Coordinates: 19.0399°; –70.5193°.
Type specimen: Type: Natural History Museum of Neuchâtel, Rue des Terreaux 14, 2000 Neuchâtel, Switzerland, slide No. 95–2. Paratype: Laboratory of Soil Bioindication, Department of Soil Geography, Faculty of Soil Science, Lomonosov Moscow State University, slide No. 4–2020.
Etymology: The species name was chosen to honour our esteemed colleague Enrique Lara, as a recognition for his major contribution to the molecular taxonomy and phylogeny of testate amoebae. We believe he may be amused by the fact that we name in his honour a species which is not straightforward to classify based solely on morphological data and clearly calls for molecular phylogenetic analyses … to which he has so greatly contributed.
Comparison between the two populations: The two populations largely overlap in length and width (Fig. 5) and do not differ either in general shape (Sup. Fig. 1) and other characters (not illustrated).
Related species: There is no possible confusion with C. australis and C. murrayi as their shape is very different (Figs. 6 & 7). The two most similar species are C. certesi and C. martiali. The shell of the new species is more elongated (length/width ratio: 2.03–2.58) than Certesella martiali (1.83-1.90). The length/width ratio overlaps with C. certesi (range 1.75–2.92 based on the original description and several subsequent studies (Certes 1889; Deflandre 1936; Heinis 1914; Penard 1911). The contrast is even clearer with the two known species of the genus Porosia – P. bigibbosa and P. paracarinata (Table 4). Indeed, the dimensions of the new species do not overlap with any known species of genera Certesella and Porosia in a biplot of length vs. width (Fig. 7). The somewhat irregular, wavy pseudostome lip of Certesella larai may be specific to this species; but this should be assessed by a thorough comparative morphological study.
The outline of Certesella larai is similar to other species in genus Certesella (Figs. 6 & 7). However, most specimens lack the inner teeth on the neck that are considered as one of the characteristic features of this genus. While we consider it unlikely that the lack of internal teeth is an effect of phenotypic plasticity as observed for shell size in Hyalosphenia papilio (Mulot et al. 2017), we evaluate that the new species fits best in genus Certesella.
description: Published as part of Bobrov, Anatoly, Duckert, Clément & Mitchell, Edward A. D., 2021, Certesella larai (Amoebozoa: Arcellinida: Hyalospheniformes) a new soil testate amoeba species from the Dominican Republic and Chile challenges the definition of genera Certesella and Porosia, pp. 61-75 in Acta Protozoologica 60 on pages 62-66, DOI: 10.4467/16890027AP.21.007.15381, http://zenodo.org/record/10994561