Haslea tsukamotoi Sterrenburg & Hinz, 2015

Sterrenburg, Frithjof A. S., Tiffany, Mary Ann, Hinz, Friedel, Herwig, Wulf E. & Hargraves, Paul E., 2015, Seven new species expand the morphological spectrum of Haslea. A comparison with Gyrosigma and Pleurosigma (Bacillariophyta), Phytotaxa 207 (2), pp. 143-162 : 151-152

Haslea tsukamotoi Sterrenburg & Hinz , sp. nov. ( Figs 14, 15 : LM, 33–38: SEM)

Type:— “ Toque-Toque Grande Beach, Sao Sebastiao, Sao Paulo, Brazil, June, 30, 2012, leg. R. Y. Tsukamoto ”, geographic coordinates 23°83’ S, 45°51’ W. Holotype BRM ZU9 /88, slide coordinates 13.0 E, 6.1 S., isotypes in collections Sterrenburg #724 and (SP) Herbario Maria Eneyda P. K. Fidalgo, Instituto de Botanica de Sao Paulo #SP428.775.

Valve ( Figs 14, 15 , 33, 34 ) robust, lanceolate, 40–55 μm long, 8–9.5 μm wide, with acute ends. Striae transverse slightly radiate, 16–19 in 10 μm, longitudinal finer, 18–21 in 10 μm. In LM, axial and central area so narrow that there is no visible hyaline space separating striae and raphe sternum. In SEM, the tegumental layer shows marked surface relief ( Fig. 36 ). External central raphe fissure endings approximate, forming tiny “crooks” tightly curved over about 270° around a tooth-like projection ( Fig. 36 and inset); apical endings undulating, terminating as retrograde hooks ( Fig. 38 ). At the apex a small accessory pore perforates the solid margin of the valve ( Figs 37, 38 , arrows). Basal layer: foramina apically elongated oblong, becoming about twice as wide near the margin ( Fig. 35 ). The broader peripheral foramina are not reflected as wider puncta spacing in the LM, as the widening of the foramina is at the expense of the width of the longitudinal bars of the basal layer grate. Entire internal raphe fissure and internal central raphe node (which is slightly depressed in the middle) fully tilted sideways ( Fig. 35 and inset).

Etymology:— Named after the collector, Dr. Ricardo Tsukamoto.

Habitat:— Wet beach.

Distribution:— Type locality only so far, fairly abundant.

Observations:— The marked difference in width of the median and the more peripheral internal foramina of the basal layer is a special feature in this new Haslea species and its internal and external raphe morphology is particularly unusual. The tightly curved “crooks” of its external central raphe endings have not yet been described in Haslea , where the fissures are generally described as almost straight or very slightly curved, as they are in H. feriarum and H. staurosigmoidea . Whilst sideways twisting of the internal raphe fissure over most of its length is considered a typical feature of Haslea species, at least its central portion is perpendicular to the valve plane in the species previously described, whereas in H. tsukamotoi the entire internal raphe system is fully sideways tilted, including the central raphe node. Saepes not satisfactorily visualized, no fragmented valves found.

H. tsukamotoi has much finer striae than H. howeana and H. nautica ; it is longer and has more markedly radiate striae than H. brittanica .

Figures

FIGURES 10–20. New Haslea species, LM images (DIC).All bars = 10 μm. All except Fig. 11 are stacks of 12–22 separate images. FIGURES 10, 11. H. staurosigmoidea sp. nov. Fig. 10. Holotype, Fig. 11. Isotype, aspect in normal DIC corresponding to what is seen on visual inspection.

FIGURES 33–38. H.tsukamotoi sp. nov. SEM, isotypes. Fig. 33. Large specimen, general aspect, interior view, bar = 5 μm. Fig. 34. Average specimen, general aspect, exterior view, bar = 10 μm. Fig. 35. Centre, interior, bar = 2 μm. Inset (2x enlargement): note sideways tilted central raphe node. Fig. 36. Centre, exterior, bar = 2 μm. Inset (2x enlargement): detail of crook-shaped raphe endings. Fig. 37.Apex, interior, bar = 2 μm. Note apical pore (arrow). Fig. 38. Apex, exterior, bar = 2 μm. Note apical pore (arrow).