Martinique

Martinique (mq)

Blanche-Pont de l’Alma

A. Eulin

E. Lefrançois

2018-5-12

61° 5' 20.4'' S ; 14° 42' 25.2'' E

-61.089 ; 14.707

LM : Frustules convex, heterovalvar, slightly asymmetric about the apical plane. Valves lanceolate, elliptical-lanceolate with slightly rounded to sub-rostrate apices, 7.0–15.0 µm long and 4.0–4.5 µm wide. One valve with long raphe slits, thread-like and almost straight, incomplete on the other valve, reduced to a small helictoglossa, ‘ghost’ full raphe. Axial area linear and narrow in both valvae, central area small to very small, round to elliptical. Striae and areolae not visible in LM. SEM : Heterovalvar frustules. Proximal raphe ends externally expanded and internally simple (Figs 55, 58). Terminal raphe ends curved externally to the same side of the valve and internally ending in small helictoglossae (Figs 54, 56 and 58, 59). Reduced raphe valve with a smooth axial area without depressions (Figs 57, 59). Transapical striae are slightly radial to parallel towards the apices, 30–40 in 10 µm, composed of continuous lines of areolae, ca. 50 in 10 µm. Outer openings of areolae are round and occluded by a delicate hymen. Inner openings of areolae larger than the outer, round to oval.