Bowmanites brasensis, Libertín & Bek & Drábková, 2008

Libertín, Milan, Bek, Jiří & Drábková, Jana, 2008, Two new Carboniferous fertile sphenophylls and their spores from the Czech Republic, Acta Palaeontologica Polonica 53 (4), pp. 723-732 : 725

publication ID

https://doi.org/ 10.4202/app.2008.0414

persistent identifier

https://treatment.plazi.org/id/C712DC09-FFCD-A86F-D99F-139873FAFE99

treatment provided by

Felipe

scientific name

Bowmanites brasensis
status

sp. nov.

Bowmanites brasensis sp. nov.

Figs. 2 View Fig , 3 View Fig .

Etymology: After Břasy, the type locality.

Type material: Holotype: NMP−E 6293; paratypes: WBMP−F 03760 , WBMP−F 01334 , and WBMP−F 00188 .

Type locality: Břasy (Matylda Mine), Radnice Basin, Czech Republic .

Type horizon: Base of the Whetstone volcanic horizon, directly overlying the Lower Radnice Coal, Radnice Member, Radnice Basin, Kladno Formation, Lower Bolsovian, Pennsylvanian, Carboniferous.

Material.—Specimens NMP−E 6293, WBMP−F 03760, WBMPF 01334 and WBMP−F 00188 from the Břasy (Matylda Mine) locality.

Diagnosis.—Monopodially branched sterile stems with internodes. Leaves divided into three or four lobes with sharp tips. Six leaves in whorls. Strobili borne terminally. Circular sporangia. The surface of sporangia grooved, terminal sporangia among the axis and sterile bracts. Trilete circular to subcircular spores. Rays of trilete mark three−quarters of the radius. Exine 3–6 µm thick.

Description.—Shoots are branched monopodially ( Fig. 2C, E View Fig ) and from 0.5 to 4 mm wide but thicker at the nodes. The internodes are 2–5 mm long. The narrow, elongate leaves can be divided into three or four segments, each with a prominent sharp tip ( Fig. 2A, D View Fig ). Leaves are arranged in verticills ( Fig. 2E View Fig ), up to six, deeply divided along single vein. The length of lobes is 2–5 mm. Reproductive organs are terminally borne ( Figs. 2B View Fig , 3A View Fig ). The strobili are 40–60 mm long and their width, including bracts, is 5–6 mm. The cone axis is relatively narrow, approximately 0.5 mm wide ( Fig. 3D View Fig ). Circular sporangia 1 mm in diameter ( Figs. 2B View Fig , 3B–D View Fig ) are connected to the cone axis by sporangiophores about 0.2 mm long ( Fig. 3B, C View Fig ). The surface of the sporangia is prominently grooved. Sporangiophores with terminal sporangia lie between the axis and sterile bracts ( Fig. 3D View Fig ). Sterile bracts are 4–5 mm long, hook−shaped, prominently deflected at the area with sporangiophores. Trilete spores are circular to subcircular 88(96)106 µm in diameter. Inner body 75(88)100 µm in diameter. The spores are three−dimensionally preserved ( Fig. 3E–H View Fig ). The outer exine layer, probably exospore, is almost always broken or is not preserved ( Fig. 3E–H View Fig ). Its thickness is 3–6 µm ( Fig. 3I View Fig ). Almost all spores are, therefore, preserved as isolated circular trilete inner bodies about 88 µm on average.

Discussion.—All the spores are closely similar and are comparable to the dispersed species Punctatisporites obesus .

Stratigraphic and geographic range.—Radnice Member,

Lower Bolsovian, Carboniferous, the Radnice Basin, Czech Republic.

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