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Dicroidium jordanensis

Gymnospermopsida - Corystospermales - Corystospermaceae

Taxonomy
Dicroidium jordanensis was named by Abu Hamad et al. (2008). It is considered to be a form taxon. Its type specimen is Specimen PbO UmIr 66, illustrated on Plate VIII, 1, a multi organs (Frond with cuticle), and it is a compression fossil. Its type locality is Wadi Himara, which is in a Lopingian fine channel fill siltstone/claystone in the Um Irna Formation of Jordan.

Sister species lacking formal opinion data

Synonymy list
YearName and author
2008Dicroidium jordanensis Abu Hamad et al. pp. 113-116 figs. Plates VIII–XVII; Plate XVIII, 1–6, 8–9

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RankNameAuthor
kingdomPlantae
superphylumTracheophyta
classGymnospermopsida
orderCorystospermalesThomas 1933
RankNameAuthor
familyCorystospermaceae
genusDicroidiumGothan 1912
speciesjordanensis

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.

Dicroidium jordanensis Abu Hamad et al. 2008
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Diagnosis
ReferenceDiagnosis
A. Abu Hamad et al. 2008Fronds small, bifurcated, bipinnate. Primary axis robust and smooth, bifurcating with an angle of approximately 25°. At least two pairs of pinnae are inserted below the bifurcation; frond portions above bifurcation more-or-less ovate in outline, tapering towards the apices and with their greatest width in the middle. Pinnae alternating to suboppositely attached, at angles of between 30° and 70°, bearing up to 17 pinnules at each side. Pinnules normally widely spaced but sometimes overlapping, in alternating or subopposite position; pinnules broadly attached, decurrent, asymmetrical, tongue-shaped to triangular in outline with rounded-to-acute apices pointing towards pinna apices. Basiscopic pinnules more obliquely attached than acroscopic pinnules; basal basiscopic pinnule semi-circular in outline. Pinnae ending in elongated, narrow terminal pinnules usually consisting of 2–3 strongly fused pinnules. Intercalary pinnules occasionally present, asymmetrically triangular and smaller than normal pinnules.

Leaves amphistomatic; stomata more abundant on lower than on upper leaf surface. Cells of upper leaf surface up to twice as large as those on lower surface. Normal epidermal cells isodiametric to elongated, rectangular. Stomatal complexes with two slightly sunken guard cells, partly underlying the adjacent subsidiary cells. Stomatal apparati monocyclic to incomplete dicyclic with a ring of four to seven subsidiary cells; subsidiary cells similarly cutinised as normal cells.
Measurements
No measurements are available
No ecological data are available

Age range: Lopingian or 259.90000 to 252.17000 Ma

Collections: one only


Time interval Ma Country or state Original ID and collection number
Lopingian259.9 - 252.17Jordan Dicroidium sp. A (type locality: 231024)