• Category
  • Length Range
    20.0-42.9 µm
  • Width Range
    9.9-15.2 µm
  • Striae in 10 µm



Valves outline is elliptic-lanceolate in large specimens and more elliptical in smaller specimens. Apices are narrowly round in large specimens becoming broadly rounded in small specimens. Valve faces are flat and may be exceptionally maculose (covered with shallow surficial depressions).

Areolae are punctate to slightly elongate along the transapical axis. Areolae bordering axial area are aligned, but other areaolae are scattered.

Striae are radiate across the valve face, becoming more pronounced toward the apices. The central area is not easily distinguished, because it is ornamented with scattered areolae and irregular depressions. There is an internal thickening of silica across the central area. The stigma is difficult to distinguish from the scattered areola, but may become apparent in deep planes of focus.

Proximal raphe ends deflect away from the stigma before curving back toward the transapical axis. This is easily distinguished on large specimens but becomes difficult to resolve in small specimens. Distal raphe ends are sickle shaped, first curving away from the stigma before reversing course as it wraps onto the mantle.

Raphe branches are straight in most specimens, though in some specimens the raphe curves slightly away from the stigma. The axial area is hyaline and tapers as it approaches the apices, becoming closest to the raphe on the side of the valve bearing the stigma.

Under SEM it can be resolved that the stigma is a slit externally and opens as a semicircle on the inside (Levkov et al. 2013)

The specimens observed in Colorado are slightly wider (< 1 µm) than those observed by Levkov et al. (2013). This difference appears to be an acceptable level of morphological variability within geographically isolated populations.

The identity of the widely reported Luticola mutica is rather uncertain. Further work is needed to determine the type of L. mutica and how L. hamiltonii compares.


Specimens presented here were collected from a high alpine wetland (~10,000 ft a.s.l.) where water was seeping out of a hillside and trickling into a small pool. This taxon was a minor member of a community dominated by Meridion anceps. This community included large taxa in the genera Neidium and Pinnularia, as well as a population of Iconella delicatissima.

JW Wetland 1
Credit: Lane Allen
Close up of some periphyton covered bryophytes that were sampled.
JW Wetland 2
Credit: Lane Allen
This is the wetland where the specimens were collected, on the north shore of Joe Wright Reservoir.

Original Description

67. Luticola hamiltonii sp. nov. (Figs 42: 1-12; 43: 1-8)

Frustules rectangular in girdle view. Valve mantle with single row of elliptic areolae. Each girdle band with single row of small, round poroids. Valves elleptic-lanceolate in larger specimens and elliptic in smaller specimens, with broadly rounded to truncate and not protracted valve apices. Valve length 18-43 µm, valve width 8.5-13.5 µm. Axial area linear throughout. Central area on both valve margins bordered by 3-5 isolated round areolae. Central area ornamented with several scattered areolae and shallow, irregular depressions. Internally, central nodule strongly thickened forming stauros. Single isolated, slit-like stigma present in central area, located close to valve margin. Internally, stigma with prominent semi-lunate opening covered with large, tongue-like occlusion. Raphe branches straight to slightly curved. In some specimens raphe branches bordered by narrow ridges. Proximal raphe endings prolonged, hook shaped, or just doubly curved, deflected to side opposite to stigma. Distal raphe fissures hooked, first deflected towards the same side as proximal raphe endings and then hooked towards the opposite side, continuing onto the valve mantle, terminating shortly before valve edge. Internal raphe slit simple. Proximal raphe endings weakly deflected towards stigma, while distally, raphe branches terminating with small helictoglossae. Transapical striae composed of 3-4 round or elongated areolae. External foramina of areolae recessed, giving uneven appearance of valve face. Internally, areolae, occluded by hymenes, forming continuous strip across valve. Transapical striae in LM punctate, radiate throughout, 12-15 in 10 µm. Marginal channel, located on valve face/mantle junction, narrow, indistinct and occluded with hymenes.

Holotype (designated here): Slide BRM 101/96. Holotype specimen is represented by Fig. 42: 6. Finder no. 379.3.

Isotype Slide BRM 101/95.

Type locality Yellowstone Park, Moorerde, USA. Leg. J. D. Möller.

Etymology: The species is named in honor of Paul Hamilton, Canadian Museum of Nature, Ottowa, Canada, for his contribution to diatom research.

Distribution Observed from several samples from Yellowstone Park

Main differential characters: Valve outline and size, shape of the valve apices.

Similar species: Luticola pseudocharcotii sp. nov., L. plausibiloides Metzeltin, Lange-Bertalot & García-Rodríguez and L. modica Li, Metzeltin & Levkov sp. nov.

Remarks: Luticola hamiltonii resembles Luticola pseudocharcotii with respect to valve outline and the stria density, however, the latter taxon has higher number of areolae per stria (6-7 areolae per stria). Luticola plausibiloides (Figs 117: 1-11) can be differentiated by the shape of the valve apices and by being consistently wider than L. hamiltonii for any given valve length. Larger Valves of L. modica (Figs 41: 6-11) have a slight constriction at the valve apices, a narrower central area and a different shape and position of the stigma.

  • Author
    Z. Levkov, D. Metzeltin & A. Pavlov 2013
  • Length Range
    18-43 µm
  • Width
    8.5-13.5 µm
  • Striae in 10µm

Original Images

Luticola hamiltonii original SEM
Luticola hamiltonii original LM
Luticola hamiltonii original images caption
Luticola hamiltonii original description

Cite This Page

Allen, L. (2023). Luticola hamiltonii. In Diatoms of North America. Retrieved September 23, 2023, from https://diatoms.org/species/luticola-hamiltonii


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Luticola hamiltonii 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.