Entomoneis annagodhei sp. nov., a new marine diatom (Entomoneidaceae, Bacillariophyta) from the west coast of Sweden

Figures & data

Table 1. Comparison of morphological features of Entomoneis annagodhei to similar species.

Species		E. japonica Osada & Kobayasi (1985) as E. alata var. japonica	E. punctulata Osada & Kobayasi (1990c)	E. vertebralis Clavero et al. (1999)	E. tenera Mejdandžić et al. (2017)	E. paludosa Osada & Kobayasi (1990c)	E. aequabilis Osada & Kobayasi (1991)	E. annagodhei sp. nov. present study
Feature
Valve	length	75–150 µm	18–99 µm	33–58 µm	11–22 µm	40–130 µm	47–57 µm	50–82 µm
	width	20–40 µm	10–19 µm	10–11 µm	3–7 µm	20–50 µm	7–9 µm	10–12 µm
	outline	linear-lanceolate	broadly linear	linear-lanceolate	broadly lanceolate	broadly linear	linear, weakly sigmoid	linear-lanceolate with slightly concave margins at centre
	apex	acuminate	acute	acute	scalpelliform	acute	broad scalpeliform	protracted in valve view; acuminate in girdle view
Junction line		bi-sinusoid	arcuate	np	straight to slightly arcuate	sinusoid	np	straight to slightly arcuate
Fibulae	basal	+	restricted to apical corner	+	+	np	np	restricted to the apex, irregularly shaped
	keel	at several levels	np	np		np	np	np
	raphe	+	+	+	29–40 in 10 µm	+	+	very dense, in form of a line; 60–64 in 10 µm
Keel		strongly sigmoid	sigmoid	sigmoid	sigmoid, often strong torsion	sigmoid, slight torsion	strongly sigmoid	narrow and sigmoid; torsion
Striae	density /10 µm	11–12	34–36	np	30–50 on valve body; 18–42 on the keel (SEM)	21–26	32–37	52–58 (SEM)
	structure	Biseriate; two rows of poroid areolae occluded by perforated hymenes	Hymenes perforated with parallel marginal linear perforations		Hymenes with rectangular perforations arranged in two parallel lines along the stria	Uniseriate; one row of elliptical poroid areolae, closed externally with hymeesn	Hymenes with perforations forming short lines	Uniseriate; areolae rounded, different in size, irregularly spaced within stria
Fascia	np	np	np	np	np	np	np	oblique transapical
Plastids	nd	nd	nd	two, plate-like	one, lobed	two, axial	nd	two, axial

np: not present.

nd: not defined.

junction line: Transition between keel and valve body.

Fig. 1. Map indicating sampling site, Nodre Älv Estuary, located at the west coast of Sweden.

Figs 2–11. LM micrographs of holotype specimen of Entomoneis annagodhei sp. nov. at different foci showing general size diminution of valves. Note oblique transapical fascia (Figs 2–6; 8 and 11) and central area of the raphe canal with lanceolate slit-like opening (Figs 7, 9 and 10). Scale bar = 10 µm.

Figs 12–20. LM (Figs 12–15) and SEM (Figs 16–20) micrographs of holotype specimen of Entomoneis annagodhei sp. nov. Fig. 12. Panduriform cell containing two plate plastids and numerous intercalary bands and straight to slightly arcuate transition between valve body and keel (arrows). Figs 13–14. Linear to lanceolate valves of same specimen observed with DIC (Fig. 13) and without (Fig. 14) showing slightly concave valve margins at the centre of valve length and slightly protracted apices. Oblique transapical fascia (Fig. 13, arrow). Central area of raphe canal showing lanceolate slit-like opening (Fig. 14, arrow). Fig. 15. Girdle view of the valve with acuminate apices and pronounced narrow raphe canal separated with raphe fibulae in form of a line (arrowhead). Fig. 16. Valve view showing sigmoid raphe canal, dense transapical striae and lanceolate slit-like opening at the central raphe canal area (arrow). Fig. 17. Girdle view of the valve showing depressions at the transition between valve body and keel (arrows). Fig. 18. Girdle view of the valve showing inner structure and oblique transapical fascia (arrow). Fig. 19. Details of Fig. 16, showing fine valve striation and lanceolate slit-like opening (arrow). Fig. 20. Acuminate valve apex showing hooked terminal raphe fissure (arrow). Scale bar = 10 µm.

Figs 21–28. SEM microghraphs of Entomoneis annagodhei sp. nov. Fig. 21. Internal valve view showing apical and central sub-compartments (arrows). Fig. 22. External valve view showing oblique transapical fascia and lanceolate slit-like opening of deep raphe canal. Fig. 23. Internal view of central valve area showing oblique transapical fascia with few isolated areolae (arrowheads), central raphe fissures opening into fascia and dense raphe fibulae forming a line (arrow). Fig. 24. External valve view showing acuminate apex and dense smooth and parallel transapical striae and virgae. Fig. 25. External valve view showing linear to undulate external ridges running more or less parallel, and adjacent to the raphe (arrows). Fig. 26. Internal valve view of the apical sub-compartments and irregularly shaped and thickened basal fibulae (arrow). Figs 27–28. External and internal valve view with areola details. Scale bar = 10 µm (Fig. 21), 2 µm (Figs. 22–24), 5 µm (Figs. 25–26), 1 µm (Figs. 27–28).

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