Eunotia mugecuo, Luo & You & Yu & Pang & Wang, 2019

Luo, Fen, You, Qingmin, Yu, Pan, Pang, Wanting & Wang, Quanxi, 2019, Eunotia (Bacillariophyta) biodiversity from high altitude, freshwater habitats in the Mugecuo Scenic Area, Sichuan Province, China, Phytotaxa 394 (2), pp. 133-147 : 136-137

Eunotia mugecuo sp. nov. ( Figs 2–18 ; holotype = Fig. 6 )

Valves arched, clavate, dorsal margin slightly curved or straight in the smaller specimens, ventral margin moderately concave to straight and almost parallel to the dorsal margin, ends broadly rounded, length 9–23 μm, and breadth 3–4 μm. Striae parallel at the center of the valve, becoming radial at the ends, 18–20/10 μm. Areolae indistinct under LM. In SEM, external raphe fissures at the junction between valve face and mantle and terminal raphe fissures extend slightly onto the valve face ( Figs 14–15 ). Areolae rounded, ca. 50/10 μm ( Figs 15–16 ). Internal valve view shows one sesile rimportula present at one apex, with a large opening ( Figs 16–18 ).

Locality: China. Sichuan Province: Mugecuo Scenic Area, 30º10′15″N, 101º52′24″E. This new species was found in Qisehai Lake, collected by Q-X. Wang, J-G. Cao, & Y. Cao et al. in August 2015.

Holotype: SHTU! slide and material SC201508079, Biology Department Diatom Herbarium , Shanghai Normal University, Shanghai, China, here illustrated as Fig. 6 .

Isotypes: COLO! material 628100, University of Colorado, Museum of Natural History Diatom Herbarium, Boulder, USA.

Etymology: The species is named for its type locality within Mugecuo Scenic Area.

Remarks: E. mugecuo sp. nov. is similar to E. faba (Ehrenberg) Grunow ( Lange-Bertalot et al., 2011: 97) and E. botuliformis Wild, Nörpel & Lange-Bertalot ( Lange-Bertalot, 1993: 29). E. mugecuo differs from E. faba mainly in the latter’s valve being longer and wider, as well as a notch on the ventral side, and it occasionally appears weakly broadly nose-like ( Lange-Bertalot et al., 2011). The apices of E. mugecuo are obviously broader than E. botuliformis ( Lange-Bertalot, 1993) .

Habitats: This species has been identified in two samples from Qisehai Lake (sample numbers: SC201508079 and SC201508081). The collected material was a mixture of floating viscous or flocculent substance and filamentous algae. This species was rare in our samples, as only 1–2 were observed in a slide.

Distribution: China (This paper)

Figures

FIGURES 2–18. E. mugecuo sp. nov.. 2–13. LM images; 6. Holotype; 14–18 SEM images; 14. External valve end; 15. External valve view; 16. Internal valve view; 17–18. Terminal ends of internal valve, arrow show a rimoportula. LM scale bars, 10 μm.