Ctenophora saxonica D. M. Williams & Van de Vijver 2023, comb. nov.
Creators: name: Williams, David M.
name: Vijver, Bart Van De
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Chromista
Ochrophyta
Bacillariophyceae
Fragilariales
Fragilariaceae
Ctenophora
Ctenophora saxonica

description: Ctenophora saxonica (Kütz.) D.M.Williams & Van de Vijver, comb. nov. (Figs 32–52)
Basionym: Synedra saxonica Kütz. 1844, Die kieselschaligen Bacillarien oder Diatomeen: 68, pl. 15, fig. XIV (see Figs 32–34)
Synonym: Synedra pulchella var. saxonica (Kütz.) Grunow in Van Heurck 1881, pl. 41, fig. 3 (see Figs 39, 40)
Ctenophora pulchella var. saxonica (Kütz.) H.Schönf. 1907: 104, 248, invalid
Registration: http://phycobank.org/104111 (name); http://phycobank.org/104119 (type)
TYPE:— GERMANY, “[…] in süssen und salzigen Gewässern an Conferven […]” (Kützing 1833: 561, 1834a: 33); “In lacu salso ad Confervam flavescentenem [Cladophora flavescens] prope Rollsdorf, fl. Halens” (Kützing 1834b [1833], Dec. VIII, no. 74), see https://data. nhm.ac.uk/object/44e566fe-37b5-45b6-8e47-9da9a9e79d08; “An C. flavescens im Salzsee bei Rollsdorf” (in Flora 17(45): 716, 1834); “Im salzigen See [Salzsee] bei Eisleben an Cladophora flavescens! im Flensburger Meerbusen an Ectocarpus: Binder!” (Kützing 1844: 68), BM 18344!, https://data.nhm.ac.uk/object/44e566fe-37b5-45b6-8e47-9da9a9e79d08, “Salzsee” (‘Kützing 166’, see Fig. 34, specimens Figs 35–8), “Salzee | Kützing”, see https://data.nhm.ac.uk/object/ 24051470 -3546-4bb4-b01d-c5262e934f85, lectotype designated here.
Valves lanceolate, gradually tapering towards sub-capitate poles; length ca. 51–97μm, width ca. 4–6μm (Figs 35–38, 41, measurements based on type specimens only). Sternum narrow, but linear, regular, slightly narrowing towards poles (Figs 35–38, 41–44). Meeting square to broadly circular-oblong shaped ‘central area’, not buttressed, simply series of infilled virgae and vimines, not extending on mantle (Figs 42, 47, arrows on Fig. 47); ‘ghost striae’ present, faint (Fig. 42). Sternum meeting and integrated with virgae, both same size; vimines reduced in size relative to virgae (Figs 45, 47, 49), appearing as mesh-work with ca. 6–8 strutted closing plate, circular with smaller pores at centre (Figs 45, 47, 49). Striae (= virgae+vimines) 13–14 (?) in 10μm, areolae ca. 20 (?) in 10μm, regularly spaced, parallel, extending onto mantle, in ca. 4 ‘rows’ (Figs 45, 47, 49). Apical pore field as ocellulimbus (sunken pore field), composed of 5 x 7 rows/ columns of pores, situated entirely on valve mantle (Figs 45, 47, 49). Spines absent. Rimoportulae simple, composed of (internally) paired lips situated on or adjacent to virga, externally occur between virgae, one at each pole, externally centred (Figs 43–6, arrow in Fig. 45). Girdle composed of two (?) open bands, VC plus one C (Fig. 49); VC plain, pi with crenulated edge to fit virgae, central smooth area to fit ‘central area’; pe separated with ridge, ca. four times larger than pi (Fig. 49, arrows). Open portions of VC meet at pole, aligned horizontally (Fig. 49).
In the protologue for Synedra saxonica, Kützing (1844: 68) refers to specimens he had previously named Exilaria fasciculata (Kützing 1833: 561, taf. 15, fig. 40, Kützing 1834a: 33, taf. III, fig. 40; Kützing 1834b [1833]: Dec. VIII, no. 74, see Figs 50–52). In this earlier account, Kützing attributed the name Exilaria fasciculata to Greville and provided a list of synonyms (Kützing 1833: 561, and Kützing 1834a: 32; in Kützing 1834b [1833]: no. 74, he cites just the two Greville publications; all of these synonyms are summarised in Table 4). In addition, he offered an additional sub-taxon (with no specified rank) with the name “β Frustulis longioribus ” itself with two synonyms (Table 4). Inspection of all the specimens related to these names is beyond the scope of this paper but potential synonym to one side, the name Synedra saxonica can be interpreted as the given valid name for Exilaria fasciculata sensu Kützing (1834b [1833]: Dec. VIII, no. 74). The locality details given for Synedra saxonica in Kützing (1844) and Exilaria fasciculata sensu Kützing are (almost) identical and one might conclude they are based on the same material.
Kützing wrote “Diese Art ist sehr häufig verbreitet, in süssen und salzigen Gewässern an Conferven, auch fand ich sie an Melosira varians und orichalcea und sogar an den Frustulen der Exilaria crystallina in der Soole bei Artern, aus der Ostsee erhielt ich sie von Herrn Lieutenant v. Suhr und Herrn Pastor Frölich” (Kützing 1833: 561, Kützing 1834a: 33). The reference to Lieutenant v. Suhr (Johannes Nicolaus von Suhr, 1792–1847) implies that Kützing may have been referring to the specimens later named ‘ Exilaria notata’ Suhr (in Kützing 1849: 47, nom. nud.). This name (‘designation’) was invalidly published as it was placed directly into synonymy with Synedra fasciculata (C.Agardh) Kütz. by Kützing (1849: 47, “ Exilaria notata Suhr Herb. ”; In Prep.; Baltic Sea [‘mer Baltique’], BM 18319, ‘Kützing 1166’). The name ‘ Exilaria notata ’ occurs only rarely in synonymy lists and is most likely derived from the entry in de Toni (1892: 662, e.g. Hustedt 1931: 218). It is unlikely anyone has studied Kützing’s “ Exilaria notata Suhr ”: the specimens are actually of a species of Tabularia (Kütz.) D.M.Williams & Round see Williams pers. obs.).
No material has yet been identified as original specimens of ‘ Exilaria fasciculata β Frustulis longioribus ’.
Synedra pulchella var. saxonica (Kütz.) Grunow (in Van Heurck 1881: pl. 41, fig. 3) is based on material from “Salzsee” (‘Kützing 166’).
description: Published as part of Williams, David M. & Vijver, Bart Van De, 2023, The diatom genus Ctenophora: A discussion on its morphology, relationships, and some species, pp. 1-26 in Phytotaxa 632 (1) on pages 9-13, DOI: 10.11646/phytotaxa.632.1.1, http://zenodo.org/record/10435352