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Anazyga orbis
Taxonomy
Zygospira orbis was named by Reed (1917) [Lectotype designated by Williams (1962).]. Its type specimen is B.54337, a shell (complete shell), and it is a 3D body fossil.
It was recombined as Anazyga orbis by Candela and Harper (2014).
It was recombined as Anazyga orbis by Candela and Harper (2014).
Sister species lacking formal opinion data
Synonymy list
| Year | Name and author |
|---|---|
| 1917 | Zygospira orbis Reed pp. 944 - 945 figs. Plate XXIV, figs. 24-27 |
| 1962 | Zygospira orbis Williams pp. 242 - 243 figs. PI. XXIV, figs. 41, 47, 48; P1. XXV, figs 12-14 |
| 2014 | Anazyga orbis Candela and Harper pp. Supplement 1 |
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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.
†Anazyga orbis Reed 1917
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| F. R. C. Reed 1917 | Shell subcircular, flattened, very gently biconvex. Pedicle-valve uniformly convex, with small elevated slightly incurved beak, apical foramen, and false area. Brachial valve with small inconspicuous and not elevated beak, and with traces of broad shallow median depression holding 4-5 ribs. Surface of valves bearing 20-22 small straight equal regular equidistant rounded ribs separated by interspaces of equal size. | |
| A. Williams 1962 | Subcircular, unequally biconvex Zygospira; pedicle valve just over one-quarter as deep as wide with a suberect umbo and an indistinct fold; brachial valve slightly wider than long and less than one-fifth as deep as wide, sulcus weakly developed and vaguely defined but embracing up to 2 pairs of submedian costae; radial ornamentation consisting of about 19 flat-topped costae with narrower interspaces and with a wave-length of 0.5 mm. at a distance of 5 mm. from the dorsal umbo; dental lamellae narrowly divergent and receding but continued anteriorly as a pair of low ridges on the floor of the valve for about one-fifth of the length of the pedicle valve; dorsal hinge-plate divided, median ridge low, but extending towards the anterior margin. |
Measurements
No measurements are available
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| Source: g = genus, f = family, c = class, p = phylum, uc = unranked clade | |||||
| References: Nesnidal et al. 2013, Hendy 2009, Aberhan et al. 2004, Meyer et al. 2009 | |||||
Age range: base of the Burrellian to the top of the Cheneyan or 456.60000 to 451.30000 Ma
Collections (2 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Burrellian | United Kingdom (Scotland) | Zygospira orbis (165046) | |
| Cheneyan | United Kingdom (Scotland) | Zygospira orbis (164412) |