Orthoseira iserentantii Kochman-Kedziora & Van de Vijver, 2024

Kochman-Kedziora, Natalia & Van de Vijver, Bart, 2024, The genus Orthoseira (Orthoseiraceae, Bacillariophyta) in Papua New Guinea with the description of two new species, Plant Ecology and Evolution 157 (2), pp. 113-124 : 113

publication ID

https://dx.doi.org/10.5091/plecevo.115801

persistent identifier

https://treatment.plazi.org/id/30E387D4-5594-5475-92F9-0F2A480CF0DE

treatment provided by

by Pensoft

scientific name

Orthoseira iserentantii Kochman-Kedziora & Van de Vijver
status

sp. nov.

Orthoseira iserentantii Kochman-Kedziora & Van de Vijver sp. nov.

Fig. 3 View Figure 3

Type locality.

Mont Wilhelm, Papua New Guinea, 9 Apr. 1987, leg. M. Fagnant.

Type.

Mont Wilhelm, Papua New Guinea, sample 17; holotype: slide BR-4817, BR; the valve representing the type is illustrated here in Fig. 3F View Figure 3 ; isotype: slide 433, University of Antwerp , Belgium .

Registration.

http://phycobank.org/104292

LM description.

Frustules cylindrical in girdle view. Valves disc-shaped. Valve dimensions (n = 20): diameter 8.0-21.5 μm, mantle height 5.0-7.5 µm. Valve face flat, sloping abruptly at the valve face/mantle junction, visible in LM as a darker circular edge. Central area very small, maximum 1/5 of the total valve diameter, irregular in shape. Three large, rounded carinoportulae present, number constant irrespective of the valve diameter. Between the carinoportulae scattered areolae present. Striae on the mantle long, uniseriate, ca 24 in 10 μm. Valve face areolae small, arranged in radiate, uniseriate striae, 20-22 in 10 µm. Caverns, internal undulations or internal valves not observed. Figure 3A-G View Figure 3 .

SEM description.

Cingulum composed of open, ligulate girdle bands bearing several, often incomplete, rows of large, rounded poroids (Fig. 3H-I View Figure 3 ). Parallel, uniseriate series of rounded, fairly large areolae present on the valve mantle, ca 24 in 10 µm. Often a clear step present halfway the valve mantle (Fig. 3J View Figure 3 ). Valve face flat, plate-like structures, irregular in shape, surrounding the entire valve face (Fig. 3K, L View Figure 3 ). Plate-like structures lacking perforations become linking plates, continuing onto the mantle as weakly raised, sometimes bifurcated ridges, flattening in the middle of the mantle height (Fig. 3H, J-L View Figure 3 ). Irregular pattern of smaller siliceous ridges, varied in length, present in the central part of the valve face, also between carinoportulae (Fig. 3L, N View Figure 3 ). Usually three carinoportulae surrounded by a siliceous collar present in very small pore-free central area (Fig. 3L, N View Figure 3 ). Striae radial composed of rounded areolae. Striae between ridges continuing on the mantle (Fig. 3H, K View Figure 3 ). Internally areolae appearing as small poroids with irregular caltrop-like structure inside (Fig. 3M, O, P View Figure 3 ). Slit-like openings present between the areolae (Fig. 3P View Figure 3 ). Carinoportulae unoccluded, ornamented with small granules (Fig. 3O View Figure 3 ). Between the carinoportulae, three long slits present (Fig. 3O View Figure 3 ), arranged in a star-shaped manner. Internal caverns not observed. Figure 3H-P View Figure 3 .

Etymology.

The species is named in honour of our (retired) colleague Dr Robert Iserentant (UCL, Belgium) to honour his life-long career as a diatom scientist.