Kittonia gigantea De Toni 1894
Creators: name: Sims, Pat A.
name: Williams, David M.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Chromista
Ochrophyta
Bacillariophyceae
Hemiaulales
Hemiaulaceae
Kittonia
Kittonia gigantea

description: Kittonia gigantea (Greville) De Toni 1894: 898 (Figs 21–30)
Basionym:— Biddulphia gigantea Greville 1864: 13, pl. 2, fig. 9
The original description of Biddulphia gigantea Greville (1864: 13) was relatively simple, referring only to the shape of the valves and the ‘horns’: “Side view more or less broadly elliptical, subacute, inflated; horns long, cylindrical, capitate; cellules large, radiating. Longest diameter about.0080” (Greville 1864: 13). The specimens described were from the “Barbadoes deposit, Cambridge estate”, with a drawing of just one valve (Greville 1864: pl. 2, fig. 9, see our Figs 21, 22; Fig. 22 is a reproduction of the original drawing with the number 2770 and the Maltwood co-ordinates ‘15/31’ added in pencil enclosed in the black box added to the drawing by us; Fig. 21 is the published drawing from Greville 1864: pl. 2, fig. 9). The drawing was clearly a composite of several specimens as the published illustration was of a complete valve (Fig. 21) and the specimen identified as the type somewhat fragmented (BM 2770, Figs 23–5, Williams 1988: 19). Greville had referred to other specimens: “Of this magnificent species I have seen several tolerably entire valves, besides fragmentary ones. Perfect horns, however, are very rare, as, being long and slender, they are readily broken off” (Greville 1864: 13, as noted above for K. hannai with the detached ‘horn’ given the named ‘ Archaeomonadopsis incerta ’ by Ramp 1940). Rather graphically, Greville writes of the valves that they are “like the ears of the Scottish shallow drinking-cup called a Quaich [A shallow two-handled drinking cup, a ‘Scottish cup of friendship’]”, and notes that “the outline is much narrower, more or less oblong” (Greville 1864: 13). At first, Greville referred to this species by the name ‘ Cerataulus giganteus ’, which appears on some of the slide labels (Table 2), but when published it was as a species of Biddulphia (Table 2). Inspection of these slides yielded a few specimens in varying degrees of completeness (Figs 26–29). Only the specimen from BM 2965 (Fig. 30) had a whole ‘horn’ still in place (Figs 26–7, arrow in Fig. 26; specimen from BM 2798 in Figs 28–9 has a partial ‘horn’, arrow). The various speCimens have lengths of 165–205μm, and widths a little smaller, roughly about half of the length, 75–100 μm. Greville’s illustrations (Figs 21, 22) suggest that the width is more similar in size than the aCtual speCimens. It is hard to account for this as Greville was normally exceedingly accurate in drawing his specimens. Our thoughts turn to the composite nature of the illustration (see Ross 2002 for a discussion on the nature and meaning of original illustrations).
When Grove & Sturt described their genus Kittonia, they included Biddulphia gigantea. They first noted Greville’s species in their earlier description of Biddulphia elaborata Grove & Sturt (1886: 325, pl. 18, fig. 9, see also Witkowski et al. 2017: 378 and for SEMs see Round et al. 1990: 278, Jousé 1977: pl. 84, fig. 13 and Sims & Hendey 2002: 388, figs 13–15), where they considered both to be a new genus (Grove & Sturt 1886: 325, full quote given above). For Biddulphia gigantea, “[…] through the kindness of W. Carruthers, Esq., F.R.S., of the Nat. Hist. Mus., been enabled to examine Dr. Greville’s authentic specimens of his Biddulphia gigantea (“T. M. S.,” Vol. xii., p. 13, PI. 2, Fig. 9), we find that the hyaline stalked processes terminate in nodular cellulose expansions larger than the small capitate ends shown in his figure. We venture to remove the form to this genus under the name of Kittonia grevilliana ” (Grove & Sturt 1887: 75). Quite why they changed the specific name is not clear, but De Toni later provided the nomenclaturally correct name of Kittonia gigantea (Greville) De Toni (1894: 898).
In their monograph on the genus, Brigger & Hanna also understood Greville’s protologue for Biddulphia gigantea to be composed not of just one specimen: “It seems quite obvious that Greville’s figure is a composite and stylized drawing. Grove & Sturt recognized this after examining authentic material but they did not clear the matter up by simply renaming the species without a good illustration. The specimens which we have shown here may or may not agree with one or more of the species represented by the original fragments [Brigger & Hanna 1965: figs 6, 7, 17, reproduced here as our Figures 31–33]. Possibly some day an opportunity will be presented to re-examine and check the original material and thereby determine if there be any diatom which can bear the name Kittonia gigantea according to the rules of nomenclature” (Brigger & Hanna 1965: 2–3). That request was partially satisfied by Williams (1988: 19), who had the opportunity of examining the original pencil drawing of Biddulphia gigantea that Greville noted to have come from slide BM 2770 and the specimen found at Maltwood Finder co-ordinates 15/31 named as ‘ Cerataulus giganteus ’ (Fig. 22), which would be considered the holotype specimen (Williams 1988: pl. 23, figs 3, 4). But no further commentary was included.
Of the Greville specimens since identified as Kittonia gigantea, five were labelled ‘ Cerataulus giganteus ’ and four as Biddulphia gigantea (Table 2). Most specimens are fragments of valves with just a few retaining the ‘horns’ or parts of them (Figs 26–9). No detached ‘horns’ were noticed.
Of the illustrations given by Brigger & Hanna of Kittonia gigantea (Brigger & Hanna 1965: figs 6, 7 and 17, reproduced here as our Figures 31–33), the most accurate is their figure 7 (our Figure 31).
description: Published as part of Sims, Pat A. & Williams, David M., 2022, Description of the new species Kittonia kempii (Biddulphiales: Kittoniaceae) with comments on Kittonia hannai P. Lefébure & Chenevière and Kittonia gigantea (Greville) De Toni, pp. 275-285 in Phytotaxa 573 (2) on pages 280-282, DOI: 10.11646/phytotaxa.573.2.7, http://zenodo.org/record/7349988