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| Váldodahkkit: | , , , , , |
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| Materiálatiipa: | Recurso digital |
| Giella: | |
| Almmustuhtton: |
Zenodo
2025
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| Fáttát: | |
| Liŋkkat: | https://doi.org/10.5281/zenodo.17955973 |
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Sisdoallologahallan:
- <p><i>Mayamaea densestriata</i> sp. nov.</p><p>Fig. 1, Table 2</p><p><b>Description.</b></p><p>In LM (Fig. 1 A – G), valves small, elliptic to linear elliptic, with pronounced sternum and broadly rounded apices, 7.6–9.0 μm in length and 3.4–4.8 μm in width (n = 20). Raphe narrow, straight. Axial area lanceolate, broad towards valve center, fusing with transverse expanded central area. Central area wide, irregular, bordered on each margin by 7–10 shortened striae. The striae radiate throughout, 32–40 in 10 μm.</p><p>In SEM (Fig. 2), internally, raphe linear with thick distinct sternum (Fig. 2 A). Central raphe endings slightly deflected to the same side of the valve (Fig. 2 B). Distal raphe fissures terminated in small helictoglossae (Fig. 2 C). Areolae small and round. Striae composed of 2–9 areolae. Central area wide. Externally, proximal raphe ends expanded and pore-like, surround by a shallow grove and slightly deflected in one direction (Fig. 2 D, E). Terminal fissures bend markedly to the opposite direction of the proximal ends (Fig. 2 F). Areolae small, round, and occluded by hymens. Striae composed of 6–8 round areolae and extended slightly onto the shallow margin of the valve.</p><p><b>Holotype.</b></p><p>The holotype is represented by the specimen illustrated in Fig. 1. The slide MBMCAS 288335 is deposited in the Marine Biological Museum, Chinese Academy of Sciences (MBMCAS), Qingdao, China.</p><p>nd = not documented.</p><p><b>Type locality.</b></p><p>Surface of moist agricultural soil (35°05.40'N, 114°08.59'E) in Yuanyang County, Henan Province, China. The type material was collected by Feichao Du on 10 May 2024.</p><p><b>Etymology.</b></p><p>The specific epithet <i>Mayamaea densestriata</i> refers to the unusually high number of areolae per stria observed in this species. It highlights a key diagnostic feature that distinguishes it from its morphologically similar congeners.</p><p><b>Distribution and ecology.</b></p><p><i>Mayamaea densestriata</i> is currently known only from its type locality. It is a terrestrial species associated with moist soil environments within cultivated agricultural landscapes.</p><p><b>Gene sequences.</b></p><p>The two sequences of <i>Mayamaea densestriata</i> have been deposited in the GenBank (SSU rDNA: PV 733928, <i>rbc</i> L: PV 740453).</p><p><b>PhycoBank registration.</b></p><p>http://phycobank.org/105610</p><p>Molecular phylogenetic analyses</p><p>The BLASTn search results showed that the SSU rDNA sequence of <i>Mayamaea densestriata</i> shares 89.37 % identity with <i>M. permitis</i> (GenBank accession PV 156110), while the <i>rbc</i> L gene exhibits 91.50 % identity with <i>M. atomus var. permitis</i> (JN 418670). Phylogenetic analyses based on concatenated SSU rDNA and <i>rbc</i> L genes place <i>M. densestriata</i> firmly within the well-supported clade comprising all currently recognized <i>Mayamaea</i> species (Fig. 3). Within this clade, <i>M. densestriata</i> occupies an independent branch and is placed at the basal position relative to a subclade including <i>M. terrestris</i>, <i>M. pseudoterrestris</i>, <i>M. arida</i>, <i>M. vietnamica</i>, <i>M. atomus var. atomus</i>, <i>M. permitis</i>, <i>M. atomus</i>, <i>M. fossalis var. fossalis</i>, and <i>M. atomus var. permitis</i> (ML = 92, BI = 0.68). Together, they are resolved as the sister to another <i>Mayamaea</i> subclade, including <i>M. sweetloveana</i> and <i>M. ectorii</i> with high support (ML = 100, BI = 1.00). The clade of <i>Mayamaea</i> is resolved as the sister group to a clade composed of <i>Pinnularia</i> Ehrenberg and <i>Caloneis</i> Cleve species (ML = 99, BI = 1.00), forming a monophyletic lineage of the family Pinnulariaceae.</p>