Valves are small. Valves are elliptic-lanceolate with cuneate apices. The axial area is narrow. The central area forms a distinct, asymmetric fascia, broadly expanded near the margin on one side and narrow on the other. The fascia may contain shortened, marginal striae. The raphe is linear, with relatively widely separated and inflated proximal ends. The striae are radiate throughout. Areolae are coarse, punctate and visible in LM.
Note that this taxon lacks the features of the genus Navicula sensu stricto. While it was transferred into Mayamaea, as Mayamaea ingenua (Hust.) Lange-Bert. and G.Hofmann 2011 (Hofmann et al. 2013), there is no discussion of the rationale for the transfer.
SEM images on this page show that the internal surface of the valve possesses depressed (closer to the external surface of the valve) areolae. The areolae also have hymenate. This character might distinguish Mayamaea from small Sellaphora that have occlusions at the level of the internal valve surface. Future work may demonstrate that this taxon is aligned with yet another genus.
This taxon was verified in piedmont rivers of the southeast US, particularly those impacted by pollutants (Bishop et al. 2017).
Valvae rhomico-ellipticae apicibus obtuse rotundatis, circiter 7,5 μ longae et 3,5 latae. Rhaphe directa poris centralibus distantibus, area axialis angustissima, area centralis lata, asymmetrica, usque ad marginem dilatata. Structura valida, striae transapicales randiantes circiter 24 in 10 μ, grosse punctatae.
Nur im Maschinenfleet, sehr selten im Gundschlamm vor dem Gröpelinger Fleet, aber an diesem Fundort vielleicht kaum autochthon. Ökologisch nach diesem Einzelfund nicht zu charakterisieren.
From 10/14/2015 until 4/25/2025, this taxon appeared as Navicula ingenua Hust. 1957. We tentatively make the update to recognize the transfer to Mayamaea ingenua (Hust.) Lange-Bert. and G.Hofmann 2011 (Hofmann et al. 2013). The taxon clearly does not belong to Navicula, but further work may show a closer alignment to another genus - Marina Potapova and Sarah Spaulding
Polaskey, M., Bishop, I. (2016). Mayamaea ingenua. In Diatoms of North America. Retrieved April 26, 2025, from https://diatoms.org/species/50885/mayamaea_ingenua
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Mayamaea ingenua 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.