Charbeckia macrophylla gen. et sp. nov. from the Lower Mississippian Price (Pocono) Formation of southeastern West Virginia.
A fossil plant discovery from the Price (Pocono) Formation of southeastern West Virginia provides new information on the poorly known compression floras of the Lower Mississippian of North America. The new plant described herein consists of long tapering bipinnate fronds with imbricate basal pinnae, planate apical pinnae, and unlobed, elliptical to obovate pinnules with open dichotomous venation. Veins concentrated in the medial region of the pinnule curve toward the lateral margin, suggestive of an early stage in the evolution of a midrib. Pinnules exhibit a distinctly revolute or otherwise reinforced margin. The exceptional length of some fronds (over 1m) and pinnule size (some over 3cm by 2cm) strongly contrast with the generally diffusely branched fronds and small or highly dissected pinnule morphology that typify Early Mississippian leaf taxa. A new generic assignment, Charbeckia macrophylla, is thereby justified. The rigid appearance of the tapering rachis, the imbricate pinnae that appear to have resisted compression, and the reinforced pinnule margins imply thick evergreen leaves, perhaps adapted for drought tolerance. A possible Calamopityalean affinity is indicated by the size of the fronds and the stout petioles, which fall within the expected size range of the Kalymma-type petiole bases described from the nearby New Albany Shale of Tournaisian age.
Department of Biology, Southwest Texas State University, 78666, San Marcos, TX, USA
MJ
Knaus
GR
Upchurch
WH
Gillespie