Cosmioneis regigeorgiensis Zidarova, Kopalová & Van de Vijver, 2016

Zidarova, Ralitsa, Kopalová, Kateřina & Vijver, Bart Van De, 2016, Ten new Bacillariophyta species from James Ross Island and the South Shetland Islands (Maritime Antarctic Region), Phytotaxa 272 (1), pp. 37-62 : 42-43

Cosmioneis regigeorgiensis Zidarova, Kopalová & Van de Vijver , sp. nov. ( Figs 35–45 )

LM observations ( Figs 35–42 ): Frustules in girdle view rectangular ( Fig. 35 ). Valves linear with parallel margins, showing occasionally a slight concavity in the middle ( Fig. 41 ). Valve apices protracted, rostrate, bluntly rounded. Pseudosepta present ( Fig. 38 ). Valve dimensions (n=10): length 35–50 μm, width 9.5–10.5 μm. Axial area very narrow, linear. Central area small, elliptic ( Fig. 37 ) to rounded ( Fig. 42 ). Raphe filiform, straight to weakly undulated. Proximal raphe endings almost straight, drop-like. Distal fissures elongated, sickle-shaped. Striae coarsely punctate, weakly to moderately radiate in the middle, where more distantly spaced, 8–11 in 10 μm, becoming more radiate and denser towards the apices, 16–18 in 10 μm. Areolae visible in LM, ca. 22–24 in 10 μm. SEM observations ( Figs 43–45 ): Mantle margin clearly undulating ( Fig. 43 ). Girdle consists of several perforated bands ( Fig. 43 ). Striae uniseriate, composed of small, rounded areolae ( Fig. 44 ). Proximal raphe endings spathulate. Distal fissures shortly continuing onto the mantle ( Fig. 44 ). Internally, large pseudosepta clearly visible ( Fig. 45 ). Central nodule well developed, clearly raised ( Fig. 45 ). Proximal raphe endings anchor-shaped ( Fig. 45 ). Distal endings terminating onto small helictoglossae. Striae forming one long groove, covered by porous hymenes. Virgae weakly raised ( Fig. 45 ).

Type: — ANTARCTICA. South Shetland Islands: King George Island, Fildes Peninsula, sample KGI9 (62° 11’ 34.0” S, 58° 55’ 47.6” W), B. Uzunov, 30 January 2013 (holotype BR! 4451, isotype PLP! 305).

Etymology: —The specific epithet ‘ regigeorgiensis ’ refers to the island where the species was described from: King George Island, ‘ regi ’ (from Latin ‘ rex ’, meaning king) and ‘ georgiensis ’ (from George).

Ecology and confirmed distribution: — Cosmioneis regigeorgiensis has only been found in the type locality on King George Island. The sample was an endolithic algal sample, taken from a cracked coastal rock. The dominant species in the sample was Humidophila vojtajarosikii Kopalová et al. in Kopalová et al. (2015: 126) and contained, besides other Humidophila taxa and several Luticola species, Achnanthes taylorensis D.E. Kellogg et al. (1980: 174– 175) and several marine species, probably blown on the rock surface by seasprays.

Family Naviculaceae

Genus Mayamaea Lange-Bertalot (1997: 71)

Figures

FIGURES 35–45. Cosmioneis regigeorgiensis sp. nov. LM & SEM pictures taken from the holotype population (sample KGI9) from King George Island, South Shetland Islands. 35–42. LM views of 8 valves from the type population. Fig. 35 shows the girdle view. 43. SEM view of the mantle and girdle bands. 44. SEM of an entire valve, external view. 45. SEM of an entire valve, internal view. Scale bar represents 10 μm.