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Pseudocyrtodonta obtusa
Taxonomy
Nucula obtusa was named by Barrande (1881). It is a 3D body fossil. Its type locality is Sterboholy (= Štěrboholy), Prague, which is in a Zahorany transition zone/lower shoreface limestone/limestone in the Zahorany Formation of the Czech Republic.
It was recombined as Myoplusia obtusa by Kříž and Steinová (2009); it was recombined as Pseudocyrtodonta obtusa by Pfab (1934) and Steinová (2012).
It was recombined as Myoplusia obtusa by Kříž and Steinová (2009); it was recombined as Pseudocyrtodonta obtusa by Pfab (1934) and Steinová (2012).
Synonymy list
| Year | Name and author |
|---|---|
| 1881 | Nucula obtusa Barrande figs. pl. 272 f. I/1-17 |
| 1934 | Pseudocyrtodonta obtusa Pfab figs. pl. 3 f. 12 |
| 2009 | Myoplusia obtusa Kříž and Steinová pp. 421 - 422 figs. 4f, G, I, J |
| 2012 | Pseudocyrtodonta obtusa Steinová pp. 342 - 343 fig. 5 |
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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.
†Pseudocyrtodonta obtusa Barrande 1881
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| J. Kříž and M. Steinová 2009 | Myoplusia with obese shell, very short anterior part of hinge and with the teeth increasing in size anteriorly and posteriorly from umbo.
Shell is small, equivalve, inequilateral, inflated, posteriorly elongated; anterior part of the shell is shorter. Umbones are prominent, in anterior position, and beeks prosogyrate. Posterior dorsal margin of the shell is slightly convex. Anterior, ventral and posterior margins are evenly rounded. Hinge is taxodont, teeth row continues below the umbo without interruption. Teeth below the umbo are smaller and their size slightly increases anteriorly and posteriorly. Internal surface is smooth. Anterior adductor muscle scar is relatively large, broadly elliptical. Posterior adductor muscle scar is larger than anterior muscle scar, broadly elliptical. Two pairs of pedal muscle scars are developed posteriorly of the anterior adductor muscle scar. First pair of elliptical pedal protractor muscle scars is close to the anterior adductor and close to hinge line. Second pair of transversely narrowly elliptical anterior pedal retractor muscle scars is developed posteriorly from the protractors, which are close and subparallel to the hinge line. Other deeply impressed elliptical accessory muscle scar is developed on the left valve close to the umbo and ventrally from the second pair of the pedal muscle scars. We suppose that it was probably the third pair of the pedal muscle scars or a median muscle scar. | |
| M. Steinová 2012 | Pseudocyrtodonta with obese shells having pronounced projection in anterior part, large and strong pseudotaxodont teeth in anterior part increasing anteriorly.
Shell small (length maximally 11.1 mm, height maximally 7.8 mm and width maximally 5.8 mm), equivalve, inequilateral, obese and slightly longitudinally elongated. Anterior and posterior margin of the shell rounded. Anterior part is much smaller than posterior part. A strong projection is developed in the anterior part. Strongly prosogyrate umbos are situated in the anterior part of the shell. Hinge actinodont, in the anterior part with 3–5 pseudocardinal (pseudotaxodont) teeth, lying under hinge line. The most anterior teeth are larger (Fig. 5D, J, M). In the posterior part of the shell one straight pseudolateral tooth (Fig. 5J, M) is developed parallel to the hinge margin. Anterior adductor muscle scar rounded (Fig. 5F, I). Posterior adductor muscle scar not well preserved. In the umbo region of lectotype three accessory rounded muscle scars (Fig. 5J) are developed. Inner surface sculpture is smooth. Shell thickness and outer surface sculpture unknown. |
Measurements
No measurements are available
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| Source: f = family, c = class | |||||
| References: Meyer et al. 2009, Aberhan et al. 2004 | |||||
Age range: base of the Zahorany to the top of the Hirnantian or 457.50000 to 443.40000 Ma
Collections (4 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Zahorany | Czech Republic (Prague) | Nucula obtusa (52739) | |
| Katian | Czech Republic (Praha) | Pseudocyrtodonta obtusa (149357) | |
| Katian | Czech Republic (Bohemia) | Pseudocyrtodonta obtusa (149356) | |
| Hirnantian | Czech Republic (Praha) | Myoplusia obtusa (149320) |