Spicaticribra kodaikanaliana Karthick & Kociolek, 2011

Karthick, B. & Kociolek, J. P., 2011, Four new centric diatoms (Bacillariophyceae) from the Western Ghats, South India, Phytotaxa 22 (1), pp. 25-40 : 29-32

Spicaticribra kodaikanaliana Karthick & Kociolek , sp. nov. ( Figures 3–4 ; holotype is illustrated in Fig. 3–A )

Frustula 8–23 µm diametro. Fultoportulae marginales 8–14 in quoque valva, 2–3µm distantes. Rimoportulae 1–3 in quoque valva, intra annulum fultoportularum. Striae radiales, rectae, aliquandro centro extensae, aliquandro prae centro terminates, 16–22 in 10 µm. Areolae 25–32 in 10µm intra strias, areolis centralibus 2-4 grandibus noncenteris.

Frustules 8–23 µm in diameter. Marginal fultoportulae 8–14 per valve, with 2–3 µm between adjacent fultoportulae. Rimoportulae number 1–3 per valve with internal extensions at same height as fultoportulae. Striae radial, straight, extending from margin to center, others extending only partially to center, 16–22 in 10 µm. Areolae 25–32 in 10 µm within striae, with central areolae 2-4 times the size of other areolae.

Type: — Kodaikanal Lake (10°14’03” N, 77°29’13”E, altitude 2090 meters above sea level), Dindigul District , Tamil Nadu, Collected by Dinesh Kumar , 22 nd December 2008 (holotype CESH-5-1882, Centre for Ecological Science Herbarium Diatom Collection , Indian Institute of Science, Bangalore, INDIA; isotypes BM 101458) .

Habitat: —Sample collected from a floating aquatic plant. This species occurs in slightly acidic water (pH: 6.25±0.12) with phosphates 0.06± 0.02 mg l -1; Nitrates: 0.55± 0.13 mg l -1 and dissolved oxygen 3.95± 0.55 mg l-1.

Distribution: —Currently known only from the type locality.

Etymology: —Named after the type locality, Kodaikanal Lake.

Observations: —In the SEM the external valve face is domed slightly ( Figs 4–A, C). Areolae are arranged into uniseriate striae, which alternate with wide, raised fascicles. The central areolae appear slightly enlarged, perhaps 2–3× greater than the diameters of other valve face areolae. There are small, siliceous nodules scattered across the periphery of the valve face and mantle ( Figs 4–A, C, D). Internally, there is a covering across the valve face, creating an internal covering over the areolae ( Figs 4–E, F, G). There is a ring of marginal fultoportulae; each bearing three satellite pores ( Figs 4-E, F). Rimoportulae number 2–3/valve, and are located at the same level as the fultoportulae ( Figs 4–E, F, G). The valvocopulae has a fimbriate margin ( Fig. 4–B). Central fultoportulae are absent.

Spicaticribra kodaikanaliana differs from Spicaticribra kingstonii Johansen et al. by the presence of small siliceous plaques on the periphery of the valve and the absence of larger sized areolae in the center of the valve (Figs 19, 20 in Johansen et al. 2008). The raised external pores of the fultoportulae (Fig. 20 in Johansen et al. 2008) are very prominent in S. kingstonii .

Order Rhizosoleniales Silva 1962

Family Rhizosoleniaceae De Toni 1890

Genus Urosolenia F.E. Round & R.M. Crawford in Round et al. 1990

Figures

FIGURE 3. Spicaticribra kodaikanaliana LM. Valves showing the size diminution series. Scale bar = 10 µm.