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Aulacoseira giraffensis (diatom)
Taxonomy
Aulacoseira giraffensis was named by Siver et al. (2019). Its type specimen is CANA # 128319, an other, and it is a 3D body fossil. Its type locality is Giraffe pipe, Lac de Gras, which is in a Lutetian terrestrial horizon in Canada.
Synonymy list
| Year | Name and author |
|---|---|
| 2019 | Aulacoseira giraffensis Siver et al. p. 360 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Aulacoseira giraffensis Siver et al. 2019 [diatom]
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| P. A. Siver et al. 2019 | valves are cylindrical, range in diameter from 3.6 to 12 µm with a mean of 7.4 µm, and in mantle height from 3 to 11.3 µm with a mean of 6.2 µm (figs 3A–E & 5). The length to width ratio (L:W) ranges from 0.36 to 2 with a mean of 0.87 (fig. 5B). Mantle striae are straight, composed of broadly oval to rectangular areolae, and range from 17 to 20 per 10 µm with a mean of 19 per 10 µm (n = 30) (figs 3D–F, 4A & 4F). On most valves, the mantle areolae do not align neatly between adjacent striae (fig. 2A, F, G, I & K). Areolae are open to the exterior, but covered on the inside of the valve with a velum that is flush with the inner mantle wall (fig. 4C–E). A series of short volae ribs is attached to the outer velum surface within the areolae chamber (figs 3F & 4D). The valve face is smooth, except for a marginal ring of pores where each pore is situated between two spines (fig. 4A). The valve face is convex or concave, and form complementary fitting pieces on adjacent frustules (figs 2B, C, E, H, J, L & 3C). The collum is distinct, from 1.3 to 1.9 µm wide (n = 15), and consists of short, closely spaced, pervalvar parallel ribs each composed of a series of fused papillae (fig. 3E & F). Steps are commonly observed on the mantle just above the collum (fig. 3D & E). Linking spines are short, more or less of even length, expand distally and form a dichotomous branching pattern (fig. 3A–E). The primary branches of the spine branch a second and sometimes a third time, often becoming pressed against adjacent spines forming contorted shapes. Separating spines were not observed. The ringleiste is shallow, U-shaped, and extends only a short distance into the cell cavity (figs 2C L, 4E & F). Rimoportulae are small rounded knobs of silica situated on the mantle just above the ringleiste (fig. 4E–F), with small internal and external openings. Up to three rimoportulae were found on broken specimens. Girdle bands are open, covered with minute pores, narrow at the open end, and becoming approximately 1.2 µm wide where the ligule fits into the adjoining band (fig. 4B). The connecting edge of the girdle bands consists of a series of fimbriae. |
Measurements
No measurements are available
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| Source: c = class | |||||
| Reference: Kiessling 2004 | |||||