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Alkaidia
Taxonomy
Alkaidia was named by Blake and Reid (1998). It is not extant. Its type is Alkaidia sumralli.
It was assigned to Paleobenthopectininae by Blake and Reid (1998); to Notomyotida by Sepkoski (2002); and to Terminasteridae by Ewin and Gale (2020) and Gale and Jagt (2021).
It was assigned to Paleobenthopectininae by Blake and Reid (1998); to Notomyotida by Sepkoski (2002); and to Terminasteridae by Ewin and Gale (2020) and Gale and Jagt (2021).
Species
A. megaungula, A. sumralli (type species)
Synonymy list
| Year | Name and author |
|---|---|
| 1998 | Alkaidia Blake and Reid p. 529 fig. 9 |
| 2002 | Alkaida Sepkoski |
| 2020 | Alkaidia Ewin and Gale p. 944 |
| 2021 | Alkaidia Gale and Jagt p. 183 |
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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.
G. †Alkaidia Blake and Reid 1998
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†Alkaidia megaungula Ewin and Gale 2020
†Alkaidia sumralli Blake and Reid 1998
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| D. B. Blake and R. Reid 1998 | Paleobenthopectinid with thick arms, attenuated arm tips. Carinals, laterals both large, flat, cross-shaped, articular facets prominent; one lateral row on each side of carinals reaching arms tips. Marginals flat, triangular, with very large spine bases; marginals flat, triangular, flat, with very large spine bases; marginal spines flat, pointed, about 3.5 mm long in holotype. Robust 3-piece Pedicellariae on dorsal arm surfaces, possibly ventral as well. Proximal adambulacrals with single enlarged subambulacral spine. | |
| T.A.M. Ewin and A.S. Gale 2020 | Terminasteridae with elongated rhombic superomarginals directed obliquely towards the radials; inferomarginals with tall, distally swollen, central spine bases and prominent groove for spine attachment; radials (except primary radial) rhombic in outline. | |
| A.S. Gale and J.W.M. Jagt 2021 | Terminasteridae with elongated rhombic superomarginals directed obliquely towards radials; inferomarginals with tall, distally swollen central spine bases and prominent groove for spine attachment; radials (except primary radial) rhombic in outline. |
Measurements
No measurements are available
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| Source: c = class, p = phylum | |||||
| References: Aberhan et al. 2004, Aberhan 1992 | |||||
Age range: base of the Late/Upper Albian to the top of the Early/Lower Cenomanian or 105.30000 to 93.50000 Ma
Collections (7 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Late/Upper Albian | USA (Texas) | A. sumralli (59875 59876 59878 59880) | |
| Early/Lower Cenomanian | USA (Texas) | A. sumralli (59881 59882 59883) |