Pyrgodiscus armatus Kitton ex Cleve 1885: 173

Williams, David M. & Sims, Pat A., 2023, Notes on the diatom collection of the Natural History Museum, London (BM) VII: An account of some original specimens of Pyrgodiscus (Bacillariophyta) with notes on Stephanogonia (Bacillariophyta), Phytotaxa 589 (3), pp. 213-229 : 217-219

Pyrgodiscus armatus Kitton ex Cleve 1885: 173 , pl. 13, fig. 13a–b, reproduced as our Figures 1, 4 (see Journal of the Royal Microscopical Society 1885: 1042); Witt 1885: 30, pl. VI, figs 7, 8; Witt 1886: 166, pl. VI, figs 7, 8, reproduced as our Figures 2, 5 (‘Arkhan- gel’skoye-Kurojedovo, Ulyanovsk’, formerly Simbirsk, USSR, see Ross & Sims 1985: 280) ( Figure 7–23 , summarised in Table 3 ).

TYPE LOCALITY:— CZECH REPUBLIC, Moravia, Augarten near Brno (= Bŗnn) (fossil, ‘Tegel’ [= marl, clay]), Miocene–Pliocene?, E. Thum (see Thum 1885: 11 [Kl̂nne & M̧ller 1885: 11], no. ‘6638, Purgodiscus [sic] armatus Kitton’; Thum 1889: 14, no. 1473: 25, no. 2991, “Tegel aus Mähren ”; Thum 1895 [1891]: 32, no. 2073: 59, no. 4226, “Tegel v. Mähren ”)

Material

CZECH REPUBLIC (MORAVIA), Augarten near Brno (= Bŗnn) (fossil, ‘Tegel’ [= marl, clay]), Miocene—Pliocene?: BM 7333! ( Figs 9, 10 ), ‘Thum, Abt. II, ---’; BM 7334! ( Figs 11–15 , two specimens, Figs 21-23 ), BR III-2-B8, BR III-2-B9, ‘Thum, Abt. VI, no. 6638’, see Thum 1885: 11 and Kl̂nne & M̧ller 1885: 11, ‘6638, Purgodiscus [sic] armatus Kitton’ slide label corrected from Purgodiscus to Pyrgodiscus ,; BM 14428! (Tempère & Peragallo, Diat. Monde entier, 1 st edn, no. 174), BM 46164! (Sturt A1101, Kitton) = Figs 21–23 , BM 46649! (Sturt A1588) = Figs 7, 8 , BM 46653! (Sturt A1592), BM 52996!, Tegel Bŗnn Mähren, ‘Thum Abt. VI, 7125’, see Thum 1885: 18 and Kl̂nne & M̧ller 1885: 18, BM 52997! (Thum, no details on label), BM 52998!, BM 56043! (Wynne Baxter 1415, Weissflog), BM 56854! (Wynne Baxter 2225), BM 57612! (Wynne Baxter 2985, Kitton) = Figs 16–18 , BM 57613 (Wynne Baxter 2986, Kitton), BM 57620 (Wynne Baxter 2993, Kitton), BM 63386! (Barker [July 1932]), BM 73527! (“Brunn”, Wise 1355), BM 73528! (“ Mähren 2088 | Thum | Abth. I IV 1423 ”, Wise 1356), BM Adams C 422! (Thum, Abt. II, ---), BM Adams GC 2630! (Kitton), BM Adams GC 2631! (Thum, Abt. VII, no. 2073), BM Adams J552! (Thum, Abt. VI, no. 6638), BM Adams J3765! (Alfredo Truan, Sep [18]86) = Figs 19, 20 , BM Adams Bess 867!, BM Adams TS320! (Thum, Abt. II, ---), BM Adams TS263! (Alfredo Truan, Julio [18]88), BM Adams F1061 (Weissflog?), ANSP Febiger 693 (Weissflog, isotype, see Mahoney & Reimer, 1997: 173), BR VIII-66-B2 (Weissflog), BR VIII-66-B3 (Weissflog 1583), BR VIII-66-B4 (Weissflog 1314); ANSP Shulze 1028, ANSP Shulze 1136, ANSP Shulze 1537, ANSP Boyer 0-5-11, ANSP Boyer E-5-5; BRM DA- 71, DA- 72 “Bŗnn Mähren Tegel”; W3075a–c?, W 3086a–f, “Bŗnn”.

RUSSIA, SINGILIEWSKY ( BM 103893 !, Hendey 5075 ex Meakin, July 1952, one specimen)

ILLUSTRATIONS:— Schmidt 1886 [Jan. 1 st 4]: pl. 92, figs 15, 16, reproduced as Figures 3, 6 [= Scḩtt 1896: 76, fig. 115A, B; = Karsten 1928: 224, fig. 247A, B; = Proschkina-Lavrenko, 1949: pl. 91, figs 4a, b], “Bŗnn (Präp. v. Thum in Janisch’s S) 660 […] Pyrgodiscus armatus F. Kitton […]”); Schmidt 1886 [Jan. 1 st]: pl. 91, fig. 8, “Szent Peter (Thum)”; Haeckel 1904, Kunstformen der Natur: pl. 84; Taylor 1929: pl. II, fig 14 (“ Pyrgodiscus armatus , ad. Nat. Bŗnn, Moravia ”); Lefébure 1947: pl. X, fig. 7 (= Jousé 1963: 121, figs 122a, b); Baranov 1942: pl.1, figs 6, 7.

Valves circUlar, diameter 70–90μm, with central dOme Or pillar, ca. 18–28μm in height, ca. 35–40μm. SUrface surrounding pillar areolate with evenly spaced stout spines, ca. 8 in all, broad at base, tapering towards tips. Surface undulates with spine at each undulation. Similar series of spines surrounding surface of pillar, stouter than those on lower part of valve, but not equal in length. Appearance when viewed from top down suggests lower series of spines alternates with those on pillar.

Thum’s various issues of the ‘ Typen Platten’ series have been briefly discussed above. All material found in BM is listed in the ‘Material’ section above, along with a note on specimens from the ANSP, BR and W collections (specimens other than BM have not been examined). There are 25 slides in all; excepting the strewn slides and those from BR and ANSP, there are 29 specimens, all structurally more or less the same as can be determined from LM ( Figs 16–23 ). All the specimens (bar two) come from the ‘Augarten near Brno (= Bŗnn)’ material. Some raw material from ‘Augarten near Brno (= Bŗnn)’ was examined but no specimens were found so electron microscopy could not be used .

4 Dates from Hanna (1969)

Several slides in BM from various Russian deposits were said to have specimens of Pyrgodiscus armatus . One, from ‘Singiliewsky’ (BM 103893!, Hendey 5075 ex Meakin, July 1952), had a single specimen mounted in girdle view. Another, from Kamishev, Russia (BM 65720! ex Swatman), was said to have a specimen of Pyrgodiscus armatus but did not, and three further slides from Russian deposits (BM 32625!, BM 32627! and BM 33210!), all strewn slides, were also said to have specimens of Pyrgodiscus armatus but no specimens could be found in any of these either.

Figures

FIGURES 1–8. Pyrgodiscus armatus Kitton ex Cleve. 1, 4. Reproduction from Cleve 1885: pl. 13, fig.13a–b. 2, 5. Reproduced from Witt 1885: 30, pl. VI, figs 7, 8. 3, 6. Reproduction from Schmidt 1886: pl. 92, figs 15, 16. 7, 8. LM of Pyrgodiscus armatus: BM 46649, Sturt A1588, d= 85 µm; cdw = 43 µm; sp = 29µm. Scale bar = 10 µm (Figs 7, 8).

FIGURES 9–15. Pyrgodiscus armatus Kitton ex Cleve LM. 9, 10. BM 7333, d= 78 µm; cd = 26 µm; sp = 29 µm. 11, 12. BM 7334, d= 72 µm; sp = 30 µm. 13–15. BM 7334, d= 73 µm; cd = 28 µm; sp = 32 µm. Scale bars = 10 µm (Figs 9–12), 20 µm (Figs 13–15).

FIGURES 16–23. Pyrgodiscus armatus Kitton ex Cleve. 16–18. BM 57612, Wynne Baxter 2985, Kitton, d= 70 µm; cd = 33 µm. 19, 20. BM Adams J3765, Alfredo Truan, Sep [18]86), d= 78 µm; sp = 19 µm. 21–23. BM 46164, Sturt A1101, Kitton, d= 70 µm; cd = 28 µm; sp = 29 µm. Scale bars = 5 µm (Figs 16–18), 10 µm (Figs 19–23).