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Pertonella dactylethra
Pertonella dactylethra Fanning, D. Edwards, J.B. Richardson Neues Jahrb. Geol. Paläontol., Abh., 183(1-3): 39. Nov 1991
- Name
- Pertonella dactylethra
- Rank
- Species
- Generic Name
- [Genus] Pertonella
- Authors (Pub.)
- Fanning U.
Edwards D.
Richardson J. B.
- Publication
- A new rhyniophytoid from the late Silurian of the Welsh Borderland [1991/11]
- Journal
- Neues Jahrbuch für Geologie und Paläontologie Abhandlungen
- Volume
- 183
- Issue
- 1-3
- Page number
- 39
- Year
- 1991
- Fossil Status
- stems (with sporangia)
- Stratigraphy
- Pridoli
- Location
- Perton Lane Quarry, near Stoke Edith, Herefordshire, U.K.
- Paleoregion
- Laurussia (Avalonia)
Data for Holotypus
- Repository
- National Museum of Wales, Cardiff, U.K.
- Repository Number
- NMW 84.14 G1
- Diagnosis
- Plant with isotomously branching smooth axes 0.16 mm - 0.42 mm (i = 0.27 mm, n = 16) terminating in discoidal sporangia 0.62 - 1.69 mm wide (i = 1.12 mm, n =28) and 0.2 - 0.4 mm high (i = 0.3 mm, n = 3). Subtending axes increase in width below sporangia, so that diameter of contact area is at least a third of the width of the sporangium. Sporangial emergences on side, proximal and distal parts of sporangia, 130 - 180 p,m wide and 130 - 250 p,m long are broadest at base, ± parallel-sided for most of length and have rounded apices; emergences ± circular in cross section. Isospores 34 - 45 p,m in diameter (i< = 39 p,m, n = 20) with subcircular to subtriangular ambs. Trilete mark consisting of prominent folds (tectum) which increase in height towards the equator. Exine 2 - 4 p,m slightly thickened equatorially. Contact areas well-defined. Proximal sculpture consists of a band (3 - 4 p,m wide) of variable sculpture following the curvaturae perfectae and confluent with a broad band of grana and microconi flanking the trilete mark. Curvatural band consists of sculpture which varies radially on an individual spore and also between specimens. As seen on the SEM, from the equator polewards, the sculptural type changes from low ridges separated by canaliculae, to crowded ridges surmounted by sharply pointed coni decreasing in size to grana and microconi (> 1 p,m); this innermost band is confluent with the broad sculptural band (2 - 6 p,m wide) enclosing the trilete folds. The tectum (trilete fold) also bears sparse grana and microconi. Distal surface laevigate, "roughened" and punctate or sparsely granulate. Distal exine c. 2 p,m.
