Odontidium neolongissimum Jüttner, D.M. Williams, Levkov, Falasco, Battegazzore, Cantonati, Van de Vijver, Angele & Ector, 2015

Jüttner, Ingrid, Williams, David M., Levkov, Zlatko, Falasco, Elisa, Battegazzore, Maurizio, Cantonati, Marco, Vijver, Bart Van De, Angele, Catalena & Ector, Luc, 2015, Reinvestigation of the type material for Odontidium hyemale (Roth) Kützing and related species, with description of four new species in the genus Odontidium (Fragilariaceae, Bacillariophyta), Phytotaxa 234 (1), pp. 1-36 : 13-18

publication ID	https://doi.org/ 10.11646/phytotaxa.234.1.1
persistent identifier	https://treatment.plazi.org/id/7A418011-FF83-677F-71DC-9A27FC82F9B4
treatment provided by	Felipe
scientific name	Odontidium neolongissimum Jüttner, D.M. Williams, Levkov, Falasco, Battegazzore, Cantonati, Van de Vijver, Angele & Ector
status	sp. nov.

Treatment

Odontidium neolongissimum Jüttner, D.M. Williams, Levkov, Falasco, Battegazzore, Cantonati, Van de Vijver, Angele & Ector , sp. nov. ( Figs 61–100 View FIGURES 61–73 View FIGURES 74–92 View FIGURES 93–100 )

LM ( Figs 61–92 View FIGURES 61–73 View FIGURES 74–92 ): Frustules rectangular in girdle view ( Fig. 61 View FIGURES 61–73 ). Valves linear to linear-lanceolate, valve margins tapering gradually to broadly rounded poles, small valves elliptic-lanceolate; valve length 32–113 μm, width 9.0–11.5 μm, length/width ratio 3.2–12.4 ( Figs 62–92 View FIGURES 61–73 View FIGURES 74–92 ). Transapical ribs nearly all primary, perpendicular or at a slight angle to the sternum, 3–5 in 10 μm. Striae between ribs appear parallel or at a slight angle, 2–8 rows between pairs of ribs. Cingulum composed of many bands. SEM ( Figs 93–100 View FIGURES 93–100 ): External valve face slightly rippled with several rows of spines (spinules) located on valve face, margin and mantle including the poles ( Figs 93, 94, 96, 97 View FIGURES 93–100 ). Spines on valve face and upper part of mantle smaller than those along valve margin. Large spines regularly positioned on virgae pointing in variable directions; one or several small spines positioned on virgae adjacent to large spines ( Fig. 96 View FIGURES 93–100 ). Virgae of varying widths, vimines considerably shorter ( Figs 96, 98, 100 View FIGURES 93–100 ). Striae uniseriate, parallel to slightly radiate towards poles. Irregular sternum 1/5 to 1/4 of valve width, extending into apical pore field ( Figs 94, 96, 98, 100 View FIGURES 93–100 ). Several rimoportulae in variable locations from centre of valve face to adjacent to pore fields, replacing 2–6 vimines within a stria, externally a simple slit, internally with protruding lips ( Figs 94, 96, 98, 100 View FIGURES 93–100 ). Large apical pore fields at each pole, composed of round porelli surrounded by a rim ( Figs 94, 100 View FIGURES 93–100 ). Outer surface of mantle and bands covered with many small granules ( Fig. 97 View FIGURES 93–100 ). Girdle composed of many bands (5–7 observed), with alternating orientation, a slightly wider valvocopula and adjacent copulae with rows of 1–3 series of poroids on pars exterior and a row with a single series of poroids on pars interior ( Figs 95, 97 View FIGURES 93–100 ). Internally ribs are parallel or at a slight angle to valve margin and wider than virgae ( Figs 98-100 View FIGURES 93–100 ).

Type:— ITALY. River Talfer at Castle Bier near Runkelstein, north of the town of Bolzano (W. Grunow 1214!, collected in a ditch in the river bed; “ Odontidium anomalum var. longissima, Herb. Mus. Palat. Vindob., Acqu. 1901 , No. 1824; Odontidium anomalum var. longissima, Bozen in einem Graben am Talferbetten bei Schloss Bier, 24. April 1863, v. Hausmann No.46”, holotype, Figs 61–73 View FIGURES 61–73 ).

Additional material examined: — MACEDONIA: Jablanica Mountain, peat bog above Lake Podgorecko, Macedonia, on bryophytes, (MKNDC, slide and material 2423!); ITALY: Gesso della Valletta, Regional Natural Park of the Maritime Alps, Italy, spring, (slide NMW.C.2012.021.2012. Italy.18!).

Observations:— Apart from type material, only one recently collected population from Macedonia has been found, which contained medium and small sized cells. Only very few valves of this population could be observed in SEM as the valves were corroded. There were fewer spines along the margins and granules on the cell walls were not visible, although this might be due to the poor state of preservation. In LM the two populations cannot be distinguished from each other.

Distribution and ecology:— Grunow provides no further information about the ditch in the bed of the Talfer River. The population shown from Macedonia was collected from bryophytes in a peat bog above Lake Podgorecko on the Jablanica Mountain. Other specimens have been found in the Gesso della Valletta Valley, Natural Park of the Maritime Alps, Piedmont, north-west Italy (not shown).

Nomenclature:— In 1862, Grunow published a brief description of a new variety of Odontidium anomalum W. Smith : O. anomalum var. longissimum (longissima) ( Grunow 1862: 357). His description is brief and only mentions the maximum length (in inches) of the frustules as “0.0045” (= 114 μm), in contrast to that of the valves of Smith’s O. anomalum which were “ 0.0005 –0.0012 ” (12–29 μm). Grunow provided a single drawing of a valve ( Grunow 1862: pl. 4, fig. 4, see Fig. 105 View FIGURES 101–108 ), which has the appearance of O. anomalum ( Fig. 102 View FIGURES 101–108 ). Grunow noted that the variety was apparently rare and had only been found between the bryophyte Hypnum commutatum Hedw. (≡ Palustriella commutata (Hedw.) Ochyra ) in the Arpatscher Alps, Austria ( Grunow 1862: 357). In the summary of the contents of the plates, Grunow used a different name for the single illustration of Odontidium anomalum var. longissimum (longissima), calling it instead Odontidium anomalum var. maximum ( maxima ) ( Grunow 1862: 471, pl. 4, fig. 4). Whatever the reason for this alternative name, the epithet “ maxima ” is illegitimate and superfluous as it is based solely on a figure that was previously described in the same paper under a different name, O. anomalum var. longissimum (longissima).

Here we need to digress briefly to discuss Smith’s Odontidium anomalum . William Smith described Odontidium anomalum illustrating it with line drawings of two valve views and two colonies of frustules ( Smith 1855: 7, pl. 1, fig. 8, figure reproduced here as Figs 104, 108 View FIGURES 101–108 ). Smith provided another brief description in the second volume of the Synopsis, this time offering four line drawings of frustules in girdle view, to illustrate the variation in size, and two in valve view ( Smith 1856: 16, pl. LXI, fig. 376, reproduced here as Figs 101, 103 View FIGURES 101–108 ; Smith’s specimens are very rare on slide BM 24007!, which is engraved ‘Braemar’, syntype material; specimens illustrated in Fig. 102 View FIGURES 101–108 ). Smith’s Odontidium anomalum was subsequently identified as Diatoma anceps var. anomala ( anomalum ) (W. Smith) Van Heurck (1896: 350, pl. 11, fig. 473, reproduced here as Fig. 106 View FIGURES 101–108 ), Diatoma anomala ( anomalum ) (W. Smith) Schönfeldt (1907: 98, pl. 5, figs 32, 32a, reproduced here as Fig. 107 View FIGURES 101–108 ), and Diatoma anceps (Ehrenberg) Kirchner (≡ Meridion anceps (Ehrenberg) D.M. Williams ); Odontidium anomalum is Diatoma anceps with internal cells. Subsequent studies on Meridion anceps (e. g., Williams 1990a) suggest that its identity is still far from clear and should probably be in its own genus. This will be dealt with in a subsequent paper (Williams et al., in prep.).

Grunow (1862:357) distinguished his Odontidium anomalum var. genuinum (genuina) from the variety Odontidium anomalum var. longissimum (longissima) Grunow (1862: 357), but cited Smith’s illustration of Odontidium hyemale instead of Odontidium anomalum ( Grunow 1862: 357, “…brit. Diat. XXXIV. 289” = Smith 1856: pl. 34, fig. 289). This may have been a simple error or Grunow may have mistaken the appearance of the girdle structure of Odontidium hyemale in Smith’s illustration for the internal cells of Odontidium anomalum . In girdle view, the sloping valvocopula of Odontidium hyemale appears not unlike the internal cells of Odontidium anomalum , which may have been a possible interpretation of Smith’s illustrations which are cited correctly for O. anomalum ( Smith 1856: pl. 61, fig. 376).

Grunow’s Odontidium anomalum var. longissimum (longissima) ( Grunow 1862: pl. 4, fig. 4) is distinguished from O. anomalum merely by the length of its frustules (114 μm vs. 12–29 μm); later Mayer (1919) also rejected Odontidium anomalum var. longissimum (longissima) as an independent taxon suggesting that it was just a particularly long valve of O. anomalum .

In 1863, specimens of Odontidium anomalum var. longissimum (longissima) were collected in a ditch in the bed of the River Talfer at Castle Bier near Runkelstein, north of the town of Bolzano, Italy. In Grunow’s collection in W this material has been retained in an envelope and labelled “ Odontidium anomalum var. longissima, Collectio Grunow 1214 !, Herb. Mus. Palat. Vindob., Acqu. 1901, No. 1824”. Additional comments on paper enclosed with the material states: “ Odontidium anomalum var. longissima 1214, Bozen in einem Graben am Talferbetten bei Schloss Bier, 24. April 1863, v. Hausmann No. 46”. The envelope contains the material and one line drawing of a valve view and two girdle views. Several line drawings exist made from Grunow’s collection 1214 (Sheet 5088, Acqu. 1901 in the Bildersammlung in W). The drawings made using material 1214 are labelled “ Odontidium hiemale form longissima ” (other drawings of specimens resembling those in 1214 were made from material 524 Schladming). All the line drawings based on material 1214 and 524 are of specimens that are morphologically different from the published drawing of Odontidium anomalum var. longissimum (longissima) ( Grunow 1862: pl. 4, fig. 4). Thus none of these collections in W can be considered type material and, in the absence of any relevant material, Odontidium anomalum var. longissimum (longissima) has to be typified by the illustration alone.

Grunow’s alternative specimens, those discussed above and named in manuscript by him as “ Odontidium hiemale form longissima ”, are not Odontidium anomalum var. longissimum (longissima) as represented in Grunow (1862: pl. 4, fig. 4) and hence the specimens studied here have to be considered a new species rather than a new combination based on Odontidium anomalum var. longissimum (longissima), hence we propose the name Odontidium neolongissimum . As Grunow collected specimens that we recognised as belonging to Odontidium neolongissimum , we have used his material to typify this species (Grunow 1214, Figs 61–73 View FIGURES 61–73 ).