Tryblionella ornata Bertolli, Talgatti et Torgan, 2019

Bertolli, Lucielle Merlym, Talgatti, Dávia Marciana, Nascimento, Thamires Mariah Da Silveira & Torgan, Lezilda Carvalho, 2019, Two new species of Tryblionella W. SMITH (Bacillariaceae, Bacillariophyta) from a southern Brazil salt marsh, Phytotaxa 399 (3), pp. 173-186 : 178-180

Tryblionella ornata Bertolli, Talgatti et Torgan sp. nov. ( Figs 22–40 )

LM observations: Valves broadly lanceolate with cuneate apices and median longitudinal fold remarkable, 85.71– 108.33 μm long and 31.43–35.00 μm wide. Raphe eccentric and distinct equidistant fibulae (6–8 in 10 μm), the median two farther apart. Striae inconspicuous and axial area absent. Transapical ribs very remarkable, 5–7 in 10 μm, sometimes branched.

SEM observations: There are thin apical silica projections connecting two consequent transapical ribs, forming a pattern that reminds a lace texture ( Fig. 39 ). Striae (36 in 10 μm) formed by single rows of transapically elongate poroids (40 in 10 μm), but within the “lace texture” pattern the rows may be unmade and the elongate poroids may assume apical or transversal disposals ( Fig. 39 ). This pattern is restricted to the median region of the valve, the striae closer to the valve margin are more regular ( Figs 32, 33 ), formed by rounded poroids and transapically elongate apertures are observed close to the margins ( Figs 35, 36 ). Proximal raphe endings deflected towards the valve face, forming a small obtuse central nodule ( Fig. 40 ). The valve margins are thicker than the valve face ( Figs 32, 33 , 35, 36 ) and present irregular grooves throughout its extension ( Fig. 40 ). The mantle is striated, 10 striae in 10 μm ( Figs 32, 33 , 35 ). Internally the longitudinal fold is remarkable, the poroids openings are rounded ( Fig. 34 ) and a very small helictoglossa is visible at each valve end ( Figs 35, 36 ).

Holotype: — BRAZIL. Rio Grande do Sul State, Rio Grande city, Ilha da Pólvora (32º01’14.424’’S – 52º05’59.095’’W), benthic sample collected by D. Talgatti and L. Donadel, February 18, 2011. Circled specimen on slide 6244 ( HAS — Museu de Ciências Naturais - Fundação Zoobotânica do Rio Grande do Sul, Porto Alegre, Brazil). Figures 25 and 31 corresponds to the holotype specimen.

Isotype: — BRAZIL. Rio Grande do Sul State,Rio Grande city,Ilha da Pólvora(32º01’14.424’’S – 52º05’59.095’’W), benthic sample collected by D. Talgatti and L. Donadel, February 18, 2011. Circled specimen on slide 76087 ( UPCB — Herbarium of the Universidade Federal do Paraná, Curitiba, Brazil).

Etymology: the epithet “ ornata ”, which means ornate in Latin, was attributed due to the singular ornamentation of the valves in SEM, similar to a lace texture.

Occurrence in the sites: T. ornata was observed in Ilha da Pólvora’s epiphyton and microphytobenthos in both periods, in Saco do Silveira microphytobenthos in winter and in São José do Norte in both substrates in winter and microphytobenthos in summer.

Figures

FIGURES 22–31. Tryblionella ornata sp. nov. in LM. Scale bar = 10 μm.

FIGURES 32–34. Tryblionella ornata sp. nov. in SEM. 32, 33. General external valve view. 34. General internal valve view. Scale bars = 10 μm.

FIGURES 35–40. Tryblionella ornata sp. nov. in SEM. 35, 36. Details of the valve apices in external view. 37, 38. Detail of the valve apices in internal view. Note the small helictoglossae (white arrow heads). 39. Detail of the “lace texture” ornamentation. 40. Detail of the proximal raphe endings. Scale bars = 10 μm (35–38), 2 μm (39), 1 μm (40).