Valves are linear-lanceolate with a slight marginal inflation at mid-valve, and have protracted, narrow, rostrate to subcapitate apices. Axial area is linear and narrow. The central area is transversely oriented and rectangular to bow tie-shaped. Striae are dense and unobservable under LM, except at mid-valve, where they are radiate and curved. Raphe is filiform, with inflated, unilaterally deflected proximal ends.
It should be noted that at a later date Kulikovskiy et al. also transferred this taxon from Naviculadicta to Sellaphora (2010). This later homonym is superfluous and does not have priority.
This taxon has been confirmed in samples collected from southeastern Piedmont region, from eastern Georgia up to central Virginia. It is also found farther west in relatively undisturbed lower order creeks in Mississippi and Arkansas.
Navicula stauroneoides Lange-Bertalot nov. spec. Taf. 109: 22-27
Valvae lineari-elliptico-lanceolatae apicibus obtuse protractis polis plusminusve late rotundatis. Longitudo 20-27µm, latitudo 5,5-6,5µm. Rami raphis filiformes distincte unilateraliter curvatae poris centralibus distinctis. Area axialis angusta, area centralis transapicaliter late dilatata ad instar papilio similis, areae apicales parvae sed satis aspectabiles. Striae transapicales extra partes protractas valde radiantes, in partibus protractis abrupte valde convergentes, 35-40 in 10µm. Striae utrimque areae centralis graviter abbreviatae item breviter extra area una stria brevis vel duae striae breves intermissae sunt (in microscopo photonico) non aspectabiles itaque striae ibi minus dense positae apparentes.
Typus: Praep. Eu-SF 44 in Coll. Lange-Bertalot, Bot. Inst. der J. W. Goethe - Universität Frankfurt a. M. (Fig. 80: 21,22).
Locus typicus: Petäijä Lampi, oligo-dystropher See in Zentral-Finnland, leg. A. & R. Dorn, Juni 1992
Bishop, I. (2016). Sellaphora stauroneioides. In Diatoms of North America. Retrieved October 30, 2024, from https://diatoms.org/species/sellaphora_stauroneioides
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Sellaphora stauroneioides from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:
ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.