Cymatosirella taylorii Dąbek & Witkowski, 2013

Dąbek, Przemysław, Sabbe, Koen, Witkowski, Andrzej, Archibald, Colin, Kurzydłowski, Krzyszof J. & Zgłobicka, Izabela, 2013, Cymatosirella Dąbek, Witkowski & Sabbe gen. nov., a new marine benthic diatom genus (Bacillariophyta) belonging to the family Cymatosiraceae, Phytotaxa 121 (1), pp. 42-56 : 50

Cymatosirella taylorii Dąbek & Witkowski sp. nov. ( Figs 44–51 [LM], Figs 52–58 [SEM])

Frustules rectangular in girdle view with undulated outline. Valves lanceolate to elliptical, 4–13 µm long and 1–4 µm wide. Central part of valve face and apices elevated. Valve surface areolated, with ca. 50 areolae in 10 µm. Areolae distributed over the whole valve face.

Type: — SOUTH AFRICA. Western Cape Province: eastern part of Langebaan Lagoon, Saldanha Bay , sandy sediment from the intertidal sandbank (33°6’788’’S; 18°2’631’’E) collected on 19 th February 2011 by Dąbek, Witkowski & Archibald ( SZCZ 17582 , holotype!) .

Habitat: —The eastern part of Langebaan Lagoon is a shallow, sandy tidal pool. High and low tide occur twice a day. Sea surface water temperature exceeds 18° C

Etymology: —Named after and dedicated to our friend and prominent South African diatomologist Dr. Jonathan Taylor (North-West University, Potchefstroom, South Africa).

Observations: —The frustules are rectangular in girdle view with an undulated outline ( Figs 44–47, 52 ). Cells are predominantly solitary, but occasionally two cells were found joined together ( Fig. 44 ). The girdle is broad, and composed of numerous bands bearing one row of fine puncta ( Fig. 52 ). The valves are lanceolate to elliptical, 4–13 µm long and 1–4 µm wide ( Figs 48–51, 53 ). The central part of the valve face and apices are elevated ( Figs 54, 56 ). The valve surface is strongly ornamented with areolae, ca. 50 in 10 µm ( Figs 53–56 ). Near the central elevation, areolae are randomly distributed; further towards the apices they are arranged in longitudinal rows ( Figs 53, 55, 56 ). Occlusions have not been observed. Each valve bears two ocelluli, composed of 7–10 porelli, with 1–2 central ones ( Figs 57, 58 ). The ocelluli are surrounded by a hyaline ring of silica ( Figs 53, 55, 57 ). No areolae occur near the ocelluli ( Figs 53, 57 ). Spines were observed only rarely. Processes, pili, fascia nor pseudosepta have not been observed.

Ecology and geography: — Cymatosirella taylorii has been found in only one sandy sample ( SZCZ 17582 , the holotype) from an intertidal sandbank in the eastern part of the Langebaan Lagoon. Only a dozen valves have been found. This species most probably belongs to the epipsammon .

Figures

FIGURES 44–58: Cymatosirella taylorii Dąbek & Witkowski sp. nov., Langebaan Lagoon, South Africa. All images originate from the holotype slide SZCZ 17582. Figs 44–51: LM images. Scale bar = 10 µm. Figs 52–58: SEM images. Fig. 52: Frustules in girdle view with complete cingulum, girdle band perforated by one row of poroids (arrowhead). Figs 53–55: Valve face view. Note the poroids on the valve surface without occlusions and ocelluli surrounded by the rim. Fig. 55: Valve with spines (arrowhead). Fig. 56: Internal view of the valve. Fig. 57: Ocellulus in external view, composed of 8 porelli (1 central), surrounded by an unperforated rim. Fig. 58: Ocellulus in internal view, composed of 10 porelli (2 central).