Longinata fueloepi (Hajós) D.M.Williams & P.A.Sims 2023

Williams, David M. & Sims, Pat A., 2023, The diatom genus Longinata Hajós (Bacillariophyta): structure, relationships and distribution, Phytotaxa 591 (3), pp. 209-219 : 213-215

Longinata fueloepi (Hajós) D.M.Williams & P.A.Sims comb. nov.

Registration: http://phycobank.org/103525

Basionym:— Eunotogramma fueloepi Hajós in Hajós & Stradner 1975: 936, pl. 13, fig. 19.

Holotype:— NEW ZEALAND, Campbell Plateau, South Pacific ( Hajós & Stradner 1975: fig. 1), “ DSDP Leg 29, Sample 275-1-2, 130- 132 cm […] Upper Cretaceous” ( Hajós & Stradner 1975: 935); there 5 slides in BP, of which only one is marked as ‘/1’ and is hence the holotype, BP 2800/1! = Hajós & Stradner 1975: pl. 13, fig. 19 = reproduced as our Figure 7 , additional specimen in Figure 6 )

Illustrations:— Chambers 1997:291, pl.13, fig. 35 (as ‘ Longinata acuta ’ recorded from ‘1-23, 24, 2-21, DSDP 275’, illustrated from ‘275-2-5-115/117, Slide 1-23 A’ = BM s.n.!); Harwood 1988: [pl.] 10, fig. 19 (as 19, ‘ Eunotogramma producta var. recta, J.A.Long, Fuge & James Smith , SI-19’, a wider specimen with no evidence of any ‘pegs’ or bars, questionable, but not Eunotogramma producta var. recta ).

The description given by Hajós is brief but sufficient without having further specimens (apart from Figure 6 ): “Elongate valves with two asymmetrically bent ends. The longer central part is round and separated from the shorter, pointed ends by transverse costae. Surface sparsely dotted. Length, 75μ; width, 7μ in the middle, 4μ at the ends” ( Hajós & Stradner 1975: 936). This can be slightly emended as follows:

Elongate valves with two asymmetrically poles bent in same direction ( Figs 6, 7 ). Valve centre gently swollen, tapering to shorter, pointed poles with faint transverse costae ( Fig. 7 ). Surface punctate, no sternum visible, valve length, 75μm, width 7μm at centre, 4μm at poles.

The recorded stratigraphic range indicated is summarised in Table 2 .

Longinata fueloepi appears to have one, maybe two, cross-members, but the published images in both Hajós & Stradner and Chambers are not that clear. The valve depicted in Hajós & Stradner has a kink in the valve at either end towards each pole, one third of the way down. Longinata fueloepi is retained as a separate species for the time being and assumed, unsatisfactorily, on its general appearance rather than any specific character, to be a species of Longinata .

Longinata acuta is recorded from DSDP 275, 2-1; 130-132, which may be specimens of Longinata fueloepi .

Figures

FIGURES 1–11: Longinata acuta Figs 1, 2, LM holotype BP 2800/1!, New Zealand, Campbell Plateau, South Pacific, “DSDP Leg 29, Sample 275–1-2, 40-42 cm […] Upper Cretaceous”, specimen length = 90μm, width = 5μm (at widest point); Figs 3, 4, BP 2800/1!, Fig. 5, L. acuta reproduced from Hajós & Stradner 1975: pl. 13, fig. 12; Figs 6, 7, Longinata fueloepi, “DSDP Leg 29, Sample 275-1-2, 130-132 cm […] Upper Cretaceous” (Hajós & Stradner 1975: 935), Fig. 6, SEM of while valve, internal view, scale bar = 20μm, Fig. 7, reproduced from Hajós & Stradner 1975, pl. 13, fig. 19; Figs 8–11, SEM, Fig. 8, detail of poles, Fig. 9, internal view of pole showing ‘pore-field’-like structure, two arrows, Fig. 10, external view of surface of valve with ‘pegs’ arrowed; Fig. 11, external view of pole showing ‘pore-field’-like structure, arrow. Scale bars = 20μm (Figs 1–4, 6), = 2μm (Fig. 8), = 5μm (Figs 9–11, 13, 14)