• Category
  • Diameter
    8.5–16.2 µm
  • Width Range
    5.4–9.2 µm

Identification

Description

Frustules are cylindrical and joined by anchor-shaped linking spines into colonies. Both the outer and inner mantle walls are straight and parallel. The valve face is flat to slightly convex and covered with round areolae. Areolae on the mantle are sparse, irregularly shaped, appear secondarily occluded, and fail to form complete striae.

The ringleist is solid and shallow. Each valve possesses multiple rimoportulae. The external and internal expression of the rimoportulae are joined by a sinusoidal channel.

This taxon should be compared with A. biseriata (Grunow in Van Heurck) Houk, R.Klee and H.Tanaka, which was described from sediments dated to 45,000 ybp from Pudasjärvi, Finland (Sutinen 1984). Until Houk et al. (2017) illustrated extant specimens, A. biseriata was considered to be an extinct taxon. The lectotype of A. biseriata was examined (Houk 2003, Houk et al. 2017) and showed similar features to the areolae of A. newjerseyana. That is, areolae are similarly sparse or absent on the mantle. However, A. biseriata differs by having a row of areolae at the valve face/mantle interface. Aulacosiera biseriata also possesses a transverse row of coarse areolae at the collum/mantle interface, a smooth valve face, thick mantle, and notably, a deep ringleist.

Autecology

To date, this taxon is known from the Highlands ecoregion of New Jersey (Enache et al. 2022). The species is based on the type material from Surprise Lake, a site with low pH (4.8), low conductivity (18 μS/cm), moderate total phosphorus (21 μg/L), and moderate total nitrogen (0.49 mg/L). Surprise Lake is located in an undisturbed, forested watershed.

The second lake, Cedar Lake, had higher pH (7.6) and conductivity (271 μS/cm), lower total phosphorus 10 μg/L and similar total nitrogen 0.42 (mg/L).

This taxon was verified within the 2000 year sediment record of Surprise Lake. It reached its greatest relative abundance (8%) in the 31–33 cm core interval representing the year 1600 AD ± 140 (Enache et al. 2022).

Original Description

Aulacoseira newjerseyana Enache, Potapova, Polaskey & Spaulding sp. nov. (Figs 1–27)

Description. Frustules cylindrical, with moderately thick silica walls, forming straight colonies. Outer and inner mantle walls straight and parallel with a slight curvature towards the collum and valve face. Valve face flat to slightly convex. Mantle height varies between 5.4–9.2 μm, and valve diameter 8.5–12.5 μm, based on measurements of 35 and 30 valves, respectively. Collum about a quarter of the mantle height (Figs 1–9). Mantle areolae sparse, oval to oval-elongated or with oval-irregular outline, aligned into incomplete rows (Figs 1, 3, 5, 6, 8, 9). A transverse row of smaller areolae with a density of 10–14 areolae in 10 μm present near the top of the collum, and a row of larger mantle areolae present near the valve face. Mantle areolae become more elongated near the valve face/mantle junction, sometimes with two areolae fused together (Figs 1, 3, 5, 6, 8, 9). Areolae oval or elongated and irregularly placed inside wall depressions that are straight or slightly undulate and parallel to the pervalvar axis. The areolae located between the mantle and collum form a transverse row with droplike, occasionally irregular or comma shape openings (Figs 16–18, 25, 26). The collum displays a ring of striations on its bottom half (Figs 18, 25, 26). The ringleist is solid, relatively shallow, and bell-shaped in cross-section (Figs 20, 21, 23, 24, 27). The mantle is covered externally by thin, porous, and finely reticulated copulae (Figs 16, 17, 26).

Internally, the mantle wall is straight and parallel to the outer wall, with areolae covered by a reticulated velum (Figs 20–24). There are multiple rimoportulae per valve with two to three openings observed on the half portion of valve perimeter (Figs 18, 20, 21, 25). The internal openings of the rimoportulae are positioned on a gently elevated portion of the wall, slightly above the row of areolae adjacent to collum (Figs 20, 21), while the external openings are positioned below the same row (Figs 18, 25, 26). A sinusoidal channel links the internal and external openings (Figs 20, 21, 27).

Valve face entirely covered with rounded areolae, 12–14 in 10 μm. A row of more prominent areolae marks the valve face/mantle interface (Figs 10–15). Short, anchor-like linking spines (1–2 μm) are present at the valve face/mantle junction originating between two areolae (Figs 10, 11). They display anchor-like branching with secondary branching sometimes visible, providing a strong interlocking system between sibling valves, occurring every second row of areolae (Figs 16–18, 25, 26). Separation spines not observed.

Holotype. Encircled specimen on slide ANSP GC 59350, Academy of Natural Sciences, Philadelphia. The holotype specimen is illustrated in Figs 1–2, core depth interval 31–33 cm, collected 19 June 2013, by B. Taylor and J. Franken, NJDEP.

Etymology. The specific epithet refers to New Jersey, the state where the new species was found.

Ecology and distribution. So far, A. newjerseyana has only been found in two lakes, both located in the New Jersey Highlands. Surprise Lake is an acidic, soft-water, low nutrient lake, with a maximum depth of 3.4 m, located within a forested, undisturbed watershed. The lake water pH was 4.8, conductivity 18 μS cm−1, total phosphorus (TP) concentration 21 μg/L and total nitrogen (TN) 0.49 mg/L at the time of sample collection in June 2013. Cedar Lake, at the time of core collection in October 2011, had pH 7.6, conductivity 271 μS cm−1, TP 10 μg/L, and TN 0.42 mg/L.

  • Length Range
    8.5–12.5 µm
  • Width
    5.4–9.2 µm

Original Images

Aulacoseira newjerseyana orig ills
Aulacoseira newjerseyana orig des

Cite This Page

Enache, M., Potapova, M., Polaskey, M., Spaulding, S. (2022). Aulacoseira newjerseyana. In Diatoms of North America. Retrieved May 30, 2024, from https://diatoms.org/species/aulacoseira-newjerseyana

Responses

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