Stauroneis spauldingiae Bahls, 2012

Bahls, Loren, 2012, Five new species of Stauroneis (Bacillariophyta, Stauroneidaceae) from the northern Rocky Mountains, USA, Phytotaxa 67 (1), pp. 1-8 : 4

Stauroneis spauldingiae Bahls , sp. nov. ( Figs 16–21 )

Type: — USA. Idaho: Copper Lake , Shoshone County, 46.9422 o N, 115.2664 o W, 1750 m elevation, collected at 3 m depth from aquatic macrophytes by John Pierce, 29 September 1998. MDC sample 179601 ; holotype slide MDC P4- 1-1, Figs 16–18, 20–21 .

Valves lanceolate to linear-lanceolate with narrowly rostrate apices. Pseudosepta absent. Valve length 48–76 µm; valve width 12–15 µm. Raphe lateral, straight with weakly inflated proximal ends. Distal raphe ends hooked to same side. Axial area 3 x wider than raphe, expanding slightly near central area. Central stauros narrow, nearly rectangular, hardly expanding towards valve margins where shortened striae may be present. Striae radiate throughout, 19–21 in 10 µm. Areolae in striae 20-28 in 10 µm.

Etymology:— Stauroneis spauldingiae is named after Sarah Spaulding, a modern day explorer of diatoms, distant lands, and big rock walls.

Observations: — Stauroneis spauldingiae was reported by Bahls (2010: 45) as S. anceps Ehrenberg (1843: 34) . Valves of S. spauldingiae are somewhat larger, and have a lower stria density and a smaller, more rectangular stauros than specimens designated by Reichardt (1995: 25) as the lectotype of S. anceps (Sippe 1, Tafel 16, Figs 1–12 ). The occurrence of S. anceps — one of the most frequently misidentified species of Stauroneis — remains to be confirmed in the USA. In addition to the type locality, S. spauldingiae has been collected from several small lakes and ponds in western Montana and northern Idaho ( Bahls 2010). These waters have circumneutral pH and very low concentrations of dissolved solids.

Figures

FIGURES 9–24: Stauroneis sacajaweae, S. spauldingiae, and S. thompsonii. Figs 9–15: Stauroneis sacajaweae. Figs 9, 11–15: Type locality. Fig. 10: Haystack Seep, Going-To-The-Sun Road, Glacier National Park, Montana. Figs 16–21: Stauroneis spauldingiae. Figs 16–18, 20, 21: Copper Lake, Shoshone County, Idaho (type locality). Fig. 19: Lily Lake, Lemhi County, Idaho. Figs 22–24: Stauroneis thompsonii from the type locality.

FIGURES 1–8: Stauroneis clarkii and Stauroneis lewisii. Figs 1–4: Stauroneis clarkii from the type locality. Figs 5–8: Stauroneis lewisii from various locations. Figs 5–6: Blodgett Lake, Selway-Bitterroot Wilderness, Montana (type locality). Fig. 7: Fred Burr Lake, Selway-Bitterroot Wilderness, Montana. Fig. 8: Bloody Dick Pond No. 6, Beaverhead County, Montana.