Haslea sigma Talgatti, Sar & Torgan, 2014

Talgatti, Dávia, Sar, Eugenia A. & Torgan, Lezilda C., 2014, Haslea sigma (Naviculaceae, Bacillariophyta) a new sigmoid benthic species from salt marshes of Southern Brazil, Phytotaxa 177 (4), pp. 231-238 : 233

publication ID

https://doi.org/ 10.11646/phytotaxa.177.4.4

DOI

https://doi.org/10.5281/zenodo.5151160

persistent identifier

https://treatment.plazi.org/id/038587F9-FFB6-A95D-3480-FD91FE01F834

treatment provided by

Felipe

scientific name

Haslea sigma Talgatti, Sar & Torgan
status

sp. nov.

Haslea sigma Talgatti, Sar & Torgan sp. nov. ( Figs. 2–35 View FIGURES 2–23 View FIGURES 24–35 )

Description in LM: —The cells have two apically elongated chloroplasts (in valvar view) with pyrenoids axially located ( Figs. 2–8 View FIGURES 2–23 ). The frustule is delicate, the striation is inconspicuous and it is possible to visualize only the raphe sternum, the pseudostauros and the valve sides ( Figs. 9–23 View FIGURES 2–23 ). The valves are sigmoid, lanceolate, with almost parallel sides in the middle ( Figs. 2–23 View FIGURES 2–23 ). The ends are curved towards opposite sides with cuneate apices. Raphe and raphe sternum are sigmoid.

Description in SEM: — External view: The central raphe fissures are almost straight, slightly bent towards primary side of the valve and drop-shaped ( Figs. 32, 33 View FIGURES 24–35 ). The terminal raphe fissures are slightly curved to opposite sides towards the concave side of the valve and expanded slightly ( Figs. 26 View FIGURES 24–35 ˗28). Valve surface has straight, parallel and longitudinal strips of silica ( Figs. 24, 27, 32, 33 View FIGURES 24–35 ), which cover the striae and are separated by narrow slits (arrows in Fig. 27 View FIGURES 24–35 ). Two of these slits go to the end of valve and come together at the far tip of the pole ( Fig. 26 View FIGURES 24–35 ). The cingulum appears to be composed by two open, plain bands: valvocopula and copula ( Figs. 25, 28 View FIGURES 24–35 ).

Internal view: The central raphe endings are coaxial, simple, straight and not expanded ( Figs. 29, 31 View FIGURES 24–35 ), whereas each polar raphe ending is expanded and terminates in a raised and straight helictoglossa ( Figs. 34, 35 View FIGURES 24–35 ). On the primary side there is an accessory rib that accompanies the raphe close to the helictoglossa, which is raised and overlaps the raphe sternum (black arrow in Fig. 30 View FIGURES 24–35 , black arrow-head in Fig. 34 View FIGURES 24–35 ). In the center, this rib merges with one thickened virga that almost reaches to the valve margin ( Figs. 25, 29–31 View FIGURES 24–35 ). On the secondary side there is also an accessory rib, however it is shorter than that of the primary side, it is raised, but does not overlap the raphe sternum, and in the center this rib merges with one or two thickened virgae ( Figs. 29–31 View FIGURES 24–35 ). These thickened virgae form a pseudostauros that is visible in LM ( Figs. 9–23 View FIGURES 2–23 ). Striae uniseriate, parallel, formed by quadrate areolae occluded by hymenes ( Figs. 31 View FIGURES 24–35 , white arrow in 34) and crossed at a right angle by a longitudinal pattern.

Valve dimensions (n = 26): 55.8–70 µm long, 5.8–7.2 µm wide, 30–40 transapical striae in 10 µm, and 35–40 longitudinal striae in 10 µm.

Holotype: — BRAZIL. Rio Grande do Sul State, Rio Grande city, Pólvora Island (32º01’14.424’’S – 52º05’59.095’’W), benthic sample, collected by D. Talgatti and L. Bertolli, May 17, 2013. Circled specimen on slide HAS 6699 About HAS ( Museu de Ciências Naturais-Fundação Zoobotânica do Rio Grande do Sul, Porto Alegre, Brazil), here designated. Figure 12 View FIGURES 2–23 corresponds to the holotype specimen. GoogleMaps

Isotype: — BRAZIL. Rio Grande do Sul State, Rio Grande city, Pólvora Island (32º01’14.424’’S – 52º05’59.095’’W), benthic sample, collected by D.Talgatti and L. Bertolli, May 17, 2013. Circled specimen on slide LPC 13001 (Herbarium of the División Ficologia “ Dr. Sebastián A. Guarrera ”, Faculdad de Ciencias Naturales y Museo, Argentina), here designated GoogleMaps .

Etymology: —The specific epithet refers to the valve shape that resembles an “S” (σίγμα in Greek).

Ecology: — Haslea sigma was found as the second most abundant species (14.79%) and the only unique representative of the genus on the sediment surface on Pólvora Island. Other abundant taxa were Nitzschia rautenbachiae Cholnoky (1957: 76) , Nitzschia spp. and Navicula spp. This sediment was composed mainly by clay (79%) and silt (13%). The taxon was found alive in oligohaline zone (salinity 3.0 ‰), at temperature 20 ºC and pH 7.1.

Diagnosis: — Haslea sigma differs from Haslea nipkowii (Meister) Poulin & Massé by having thickened virgae forming a pseudostauros, central raphe fissures almost straight (not overlapping), and terminal raphe fissures slightly curved (not T-shaped).

LPC

Museo de La Plata

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