Comparison of diatom successions from Mazovian (Poland) and Alexandrian (Belarus) lacustrine interglacial deposits

Comparative analysis of two profiles (Gvoznitsa, Malorita district, southwestern Belarus and Krępiec, Lublin Upland, eastern Poland) of Alexandrian and/or Mazovian (=Likhvinian, Holsteinian) age shows different diatom successions which are correlated with pollen data. Various species of Cyclotella, Stephanodiscus and Aulacoseira predominate at Gvoznitsa, while the diatom flora at Krępiec is more diverse and includes also Synedra, Asterionella, and Fragilaria taxa. Certain apparently extinct taxa of Cyclotella (C. comta var. lichvinensis (Jousé) Loginova, C. comta var. pliocaenica Krasske, C. temperiana (Loginova) Loginova, C. michiganiana var. parvula Loginova (C. parvula Loginova), are typical of the Mazovian and/or Alexandrian Interglacial

Cyclotella pseudokansasica Khursevich & Kociolek 2013, sp. nov.

Cyclotella pseudokansasica Khursevich & Kociolek, sp. nov. (Figs 56–69) Type:— USA. Idaho: Owyhee County, Chalk Hills Formation, USGS Diatom Locality 5244, (Circled specimen (Fig. 61) on CAS Slide #381069, material CAS Accession Number 602190 (CAS!), holotype, designated here). Description: —Valves are circular, nearly flat, 10–23 µm in diameter, with a well-defined border between the central area and the marginal alveolate zone. Central area with a variable number of irregularly arranged areolae. Marginal zone extending from 1/3 to 1/2 of the valve radius consists of alveolate striae fascicles, 8– 12(14) in 10 µm, separated by hyaline interfascicles or costae. Striae fascicles are of equal length. They contain 3–4 rows of puncta, 40–60 in 10 µm. Alveoli are simple. Length of alveolar openings is not equal to the length of striae fascicles. Marginal fultoportulae with 3 satellite pores are located on every second–fourth costa separating alveolar openings internally. A single rimoportula occurs at one of the costae. Spines are present at the junction of the valve face and mantle at every interfascicle or costa. Remarks: — Cyclotella pseudokansasica is similar to C. kansasica in the structure of alveolae, in the location of rimoportula and marginal fultoportulae, but differs by the absence of one more or less welldeveloped depression at the center, as well as by the shorter length of alveolar openings as compared with the length of striae fascicles.Published as part of Kociolek, J. P. & Khursevich, G. K., 2013, Morphology of some fossil lacustrine centric species from the western United States assigned to the genus Cyclotella (Bacillariophyta), including four described as new, pp. 81-99 in Phytotaxa 127 (1) on pages 93-94, DOI: 10.11646/phytotaxa.127.1.11, http://zenodo.org/record/508551

Cyclotella kansasica Hanna 1932

Cyclotella kansasica Hanna (1932: 376) (Figs 10–24) Hanna 1932. University of Kansas Science Bulletin 20: 376, pl. 31, fig. 6. Material examined: — USA. Kansas: Wallace County, Diatom marl from center Sec. 11, T.11S., R 38W, Marshall ranch, North Fork Smoky Hill River, Ogallala Formation. CAS Accession Number 2383 (CAS!). This is the type material studied by Hanna (1932). USA. Kansas: Wallace County, Sec. 12, T.11S., R 38W. CAS Accession Number 604437, Slide numbers 423092, 423093 (CAS!). Description: —Valves are circular, nearly flat, 4.5–16.5 µm in diameter, with several girdle bands and a well-defined border between the central area and the marginal alveolate zone. Central area with one more or less well-developed depression at the center and a variable number of areolae which are arranged irregularly or in short radial rows. Marginal zone extending a little over 1/3 of the valve radius consists of alveolate striae fascicles, 8–12 in 10 µm, separated by hyaline interfascicles. Striae fascicles are of equal length. They contain 3–4 rows of puncta, 40–60 in 10 µm. Alveoli are simple. Length of alveolar openings is almost equal to the length of striae fascicles. Marginal fultoportulae with 3 satellite pores are located on every costa or every second costa separating alveolar openings internally. A single rimoportula occurs at the marginal ends of one of the costae. Spines are present at the junction of the valve face and mantle at every interfascicle, but they may be broken.Published as part of Kociolek, J. P. & Khursevich, G. K., 2013, Morphology of some fossil lacustrine centric species from the western United States assigned to the genus Cyclotella (Bacillariophyta), including four described as new, pp. 81-99 in Phytotaxa 127 (1) on page 85, DOI: 10.11646/phytotaxa.127.1.11, http://zenodo.org/record/508551

Cyclotella discostelliformica Kociolek & Khursevich 2013, sp. nov.

Cyclotella discostelliformica Kociolek & Khursevich, sp. nov. (Figs 25 –39) Type:— USA. Oregon: Klamath County, Sprague River, Drews Road, diatomite, (Circled specimen (Fig. 31) on CAS Slide Number 1026029, material CAS Accession Number 701883 (CAS!), holotype, designated here; duplicate of CAS Slide Number 1026029 deposited in Khursevich Collection, Minsk, Belarus, isotype, designated here). Additional material examined: — USA. Oregon: Klamath County, NE Sprague River Bridge, CAS Accession Number 600180, Slide Number 433093 (CAS!) Description: —Valve outline nearly circular, with several girdle bands, 5.0–17.0 µm in diameter. Valve surface is divided into two distinct zones with different morphologies. The central area is distinctly concave or convex with irregularly arranged areolae (5 to 17) and one to three valve face fultoportulae. The latter have three satellite pores internally and open by small aperatures externally. This central zone is separated from the marginal zone by a wide hyaline ring. Small specimens have simple alveolae. Marginal fultoportulae are located in small fovae on the gentle slope of costae. A single rimoportula has internal elongated slit and is positioned within the alveolar opening close to one of the costae. The marginal zone extends from 1/3 to ½ of the valve radius and consists of alveolate and fasciculate striae, 8–10/ 10 µm, divided by hyaline interfascicles. Interfascicles become broader towards the margin. Each fascicle has one-two rows of smaller puncta, which have a row of larger puncta on each side. Striae fascicles are of equal length. A ring of marginal chambers, separated by thicker costae, is evident internally. Alveolar chambers appear simple and complex in larger specimens. Complex alveolae are comprised of alveolar openings divided by thinner costae. The thinner costae bear marginal fultoportulae. Each fultoportula has three satellite pores, and number 4 in 10 µm. Externally, marginal fultoportulae are represented by small, circular openings. A single rimoportula is located on a thinner costa or along the slope of one of the costae. External rimoportula opening is a small, but distinct, slit. Granules may occur along the edge of the mantle. FIGURES: 38–39: Cyclotella discostelliformica. SEM. Figure 38. External view showing opening of rimoportula and fine nature of the areolae. Scale bar = 1 µm. Figure 39. Internal view showing large rimoprotula (arrow) located on the side of a costa. Central fultoportula with 3 satellite pores is evident. Scale bar = 1 µm. Cyclotella discostelliformica differs from C. idahica by its smaller size, presence of strongly concave or convex central area, external expression of the rimoportula (a distinct slit in C. discostelliformica; a small circular opening in C. idahica) and the absence of spines. This new species appears in the light microscope to resemble Discotella stelligera (Cleve & Grunow) Houk & Klee (2004: 209, figs 23, 24) but differs in the position of the rimoportula and marginal fultoportulae, (between two costae in D. stelligera and on thinner costae in C. discostelliformica). Moreover, marginal fultoportulae in C. discostelliformica have three satellite pores; D. stelligera has marginal fultoportulae with two satellite pores.Published as part of Kociolek, J. P. & Khursevich, G. K., 2013, Morphology of some fossil lacustrine centric species from the western United States assigned to the genus Cyclotella (Bacillariophyta), including four described as new, pp. 81-99 in Phytotaxa 127 (1) on pages 86-90, DOI: 10.11646/phytotaxa.127.1.11, http://zenodo.org/record/508551

Cyclotella jonesii McLaughlin 1992

Cyclotella jonesii McLaughlin (Figs 70–77) McLaughlin 1992, Diatom Research 7: p. 96, figs 1–11. Materials examined:— Oregon, Klamath Co., Forest Road, No. 3683-A, 6.6 miles W of Beatty, N of highway 140. CAS Accession Numbers 600120, 600121, 600122, Slide Numbers 436069, 436070, 436071, 436072, 436073, 436074 (CAS!) We observed two morphotypes in populations we examined. They are almost exactly the same except for size and valve outline. We present descriptions for both morphotypes even though at this time we recognize them as the same taxon, C. jonesii. Morphotype 1 (Figs 70, 72, 73, 75) Description:—Valve outline rhomboid to ellipsoid, but large forms are nearly circular. Major axis is 20 to 95 µm, minor axis 11 to 93 µm. Central area is elongated, asymmetrically undulate with the depressed portion shallower than the rise of the elevated part. Central area occupies 1/3 to 1/2 of the total valve face and contains areolae arranged in more or less radial rows. Valve face fultoportulae are absent. Striae number 7–9/ 10 µm, consisting of 2–3 rows of small puncta (with up to 30 puncta in 10 µm measured radially), and separated by interstriae. Alveolae are complex and simple. Marginal fultoportulae have three satellite pores and are located on all recessed costae within alveolar chambers internally. They open by short tubes on the external valve surface. One or two rimoportulae are present also on recessed costae between two alveolar openings. A closed valvocopula and several open copulae without puncta are present. Morphotype 2 (Figs 71, 74, 76, 77) Description:—Frustules solitary, elliptical-lanceolate in valve view, with several girdle bands. A closed valvocopula has numerous plaques along the valve. Several open bands, as a valvocopula, lack areolae. Dimensions of major axis of valves vary from 11.7 to 42.7 µm, of minor axis from 7 to 30 µm. Valve face is distinctly divided into two zones: a marginal alveolate zone and a transversely undulate, elongated areolate central area. A narrow, irregular hyaline area separates these two zones. Central area is elliptical, symmetrically undulate: elevated and depressed parts are almost equal. Areolae with internal domed cribra and external foramina are arranged mainly irregularly. One valve face fultoportula with two satellite pores internally and a round thickened aperture externally can be seen within the central area, rarely can be absent. Striae, 10–12 in 10 µm, are slightly radiate in the middle part of the marginal zone and strongly radiate towards the valve ends. Striae consisting of two-four rows of small puncta (40–50 puncta in 10 µm) are divided by interstriae (costae). Alveolae are complex and simple, 10–12 in 10 µm. Marginal fultoportulae have three satellite pores internally and open by short tubes externally. They are positioned on all recessed costae within alveolar chambers on the internal valve surface. One or two rimoprtulae are sessile internally, and each is located on a costa between two alveolar openings in the pole area. Rimoportulae open by a round apertures externally. Spines can be present on the valve face/mantle junction, but they are often broken.Published as part of Kociolek, J. P. & Khursevich, G. K., 2013, Morphology of some fossil lacustrine centric species from the western United States assigned to the genus Cyclotella (Bacillariophyta), including four described as new, pp. 81-99 in Phytotaxa 127 (1) on page 94, DOI: 10.11646/phytotaxa.127.1.11, http://zenodo.org/record/508551

The age of the oldest Scandinavian glaciations in mid-eastern Poland and southwestern Belarus

Analysis of type localities of Pleistocene deposits from mid-eastern Poland (Kozi Grzbiet, Łuków, Biała Podlaska and Wilczyn) and southwestern Belarus (Smolarka and Postolovo) has provided a new view on the age, limits and correlation of the oldest Scandinavian glaciations in the area. Integration of palaeontological data with determination of the Brunhes/Matuyama boundary (780 ka) at Kozi Grzbiet and Smolarka suggests that the first glaciation (Narevian) preceded this boundary and had a slightly smaller extent in SW Belarus than hitherto considered. The second glaciation (Nidanian) occurred slightly above or at this palaeomagnetic boundary. In Poland it is the first South Polish Glaciation, a till of which can be traced as far as the Holy Cross Mts. In SW Belarus it is represented by a till to the south of Brest and Bereza, and connected there with the oldest glaciation