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Araucaria readiae
Taxonomy
Araucaria readiae was named by Hill and Bigwood (1987). Its type specimen is RPE-045, housed in the Botany Department, University of Tasmania., a sterile axis (Cuticle), and it is a compression fossil. Its type locality is Regatta Point Eocene, which is in an Eocene fluvial-deltaic mudstone/sandstone in Australia.
Sister species lacking formal opinion data
Synonymy list
| Year | Name and author |
|---|---|
| 1987 | Araucaria readiae Hill and Bigwood p. 326 figs. 1A, C-E |
| 1990 | Araucaria readiae Hill p. 217 figs. 11-14 |
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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.
†Araucaria readiae Hill and Bigwood 1987
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| R. S. Hill and A. J. Bigwood 1987 | Leaves arranged on the axis in a close helix. Leaf length 6-7 mm, width 3-4 mm, leaves strongly keeled. Leaf base as broad as the widest point, petiole absent, apex acute. Margins entire, not appreciably thickened. Venation unknown. Leaf amphistomatous. Stomatal arrangement predominantly oblique, at a variable angle to
the long axis of the leaf. Stomata on lower epidermis in longitudinal rows in two triangular areas separated by a wide central zone. Stomata on upper epidermis with a similar distribution, but less frequent. Guard cells sunken below subsidiary cells. Florin rings inconspicuous on lower epidermis, absent from upper epidermis. Stomatal apparatus 43 µm long (36-55 µm), 30 µm wide (24-36 µm). Mean number of subsidiary cells 4.4 (4-5). Stomatal plugs present. | |
| R. S. Hill 1990 | Leaves arranged on the axis in a clise spiral. Leaf length 6-7 mm, width 3-4 mm, leaves strongly keeled. Leaf base as broad as the widest point, petiole absent, apex acute. Margins entire, not appreciably thickened. Leaf amphistomatous. Stomata on lower epidermis in longitudianl rows in two triangular areas separated by a wide central zone. Stomata on upper epidermis with a similar distribution, but less frequent. Subsidiary cells usually four, sometimes five or six. Stomatal plugs spongy. Cuticle on subsidiary cells slightly granular, outer flange smooth, oval to rectangular, rim thickened. Flange between guard and subsidiary cells small, thick and irregular, thinner around guard cell poles. Polar extensions well developed. Flange between guard cells thick, slightly granular, with small polar extensions. Epidermal cell walls not sinuous, buttressing absent. |
Measurements
No measurements are available
No ecological data are available
Age range: Early/Lower Eocene or 56.00000 to 48.07000 Ma
Collections: one only
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Early/Lower Eocene | Australia (Tasmania) | Araucaria readiae (type locality: 166977) |