Stricosus gracilis Theriot and Ashworth, 2018

Sabir, J. S. M., Theriot, E. C., Lobban, C. S., Alhebshi, A. M., Al-Malki, A. L., Hajrah, N. H., Khiyami, M. A., Obaid, A. Y., Jansen, R. K. & Ashworth, M. A., 2018, Systematics of araphid diatoms with asymmetric rimoportulae or densely packed virgae, with particular attention to Hyalosynedra (Ulnariaceae, Bacillariophyta), Phytotaxa 347 (1), pp. 1-49 : 32

publication ID

https://doi.org/ 10.11646/phytotaxa.347.1.1

DOI

https://doi.org/10.5281/zenodo.13708503

persistent identifier

https://treatment.plazi.org/id/A57F87E7-FFDD-EA58-FF5B-FD46FDEDFAB6

treatment provided by

Felipe

scientific name

Stricosus gracilis Theriot and Ashworth
status

sp. nov.

Stricosus gracilis Theriot and Ashworth sp. nov. ( Figs 83–89 View FIGURES 83–86 View FIGURES 87–89 )

Holotype:— ANSP G. C. 59326

Isotype: — ECT 4116.

Type locality: —Rabbit Key Basin, Florida, USA, collected as a epiphyte on macrophytes (24 o 58.60’ N, 80 o 50.41’ W)

Material studied: —Wild and cultured (21IV14-4 E “synedroid12”) material, isolated from type locality: ECT 4116, epiphytes collected from Penicillus spp. thalli at Rabbit Key Basin, Florida, USA (24 o 58.60’ N, 80 o 50.41’ W).

Description: —Specimens ranged from 153.1–357.5 μm long, but only 4.7–5.7 μm in width ( Figs 83–85 View FIGURES 83–86 , 87 View FIGURES 87–89 ). Valves were lanceolate with nearly parallel sides. Apices were not distinguished from the remainder of the margin until the very end when they became rounded. The sternum was prominently lanceolate, being about 1 μm wide in the valve center. Virgae density was 44–52 in μm. External pores were again difficult to resolve, but appeared to be biseriate. The internal membrane was perforated by a row of pores at the junction of the face and mantle. The full pore field of the ocellulimbus was difficult to see because it was deeply sunken ( Fig. 88 View FIGURES 87–89 ). However, it appeared that the exterior pore field was 3–4 poroids tall and 10–15 wide. There were 4–7 prominent spines overhanging each ocellulimbus ( Figs 86 View FIGURES 83–86 , 88 View FIGURES 87–89 ). Each rimoportula was 2.1–3.1 μm from the end of the valve. Internally, the slit of each rimoportula was roughly transapical and had symmetric margins. Externally, the rimoportula was a simple pore located at the edge of the hyaline region above the ocellulimbus. Girdle bands were smooth and open ( Fig. 88 View FIGURES 87–89 ).

Remarks: —Specimens observed for this species nearly reach the same maximum length as S. blumbergii (described below), but S. gracilis specimens were narrower.

Etymology: —Specimens were very narrow for their great length, and were delicate looking, hence the epithet “gracilis ”, meaning slender, slim or svelte.

ANSP

Academy of Natural Sciences of Philadelphia

G

Conservatoire et Jardin botaniques de la Ville de Genève

C

University of Copenhagen

E

Royal Botanic Garden Edinburgh

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