Taxonomy Online - Carboniferous spores part I - Species details


Species name
Vallatisporites verrucosus Hacquebard, 1957

Description
Radial, trilete, camerate, cingulizonate miospores. Amb convexly rounded triangular. Trilete mark distinct or indistinct if obscured by ornament; sutures straight, extending to margin of inner body, simple or accompanied by elevated flexuous folds of the exoexine, up to 4 µm high in polar region, which extend, decreasing in height, to the margin of the body or onto the cingulum. Exine two layered. Intexine thin, laevigate, forms inner body conformable with the equatorial outline. Exoexine closely adpressed to intexine in proximal and distal positions but separated from intexine in the equatorial plane where a well-developed cuniculus is located. Exoexine extended in the equatorial plane to form poorly differentiated bizonate cingulum. Inner thicker zone of cingulum overlaps the equatorial margin of inner body and may contain numerous internal radially orientated vacuoles. Outer zone of cingulum thinner and narrower. In some specimens differentiation of the cingulum is difficult to discern. Distal surface of exoexine densely ornamented with discrete or confluent verrucae up to 6 µm in diameter. Elements may fuse to form short irregular ridges. Verrucae are most densely distributed in the distal polar region where the largest elements are also located. Towards the equatorial margin, elements become progressively smaller and more sparsely distributed. Equatorial margin uneven but rarely displays coarse projecting ornamentation. Verrucae surmounted by small mammoid coni may be present in the distal polar region.

Other descriptions
Hacquebard, 1957, p. 313, pl. 2, fig. 13

Size
Overall equatorial diameter 55–75 µm. Diameter of inner body 41–47 µm

Remarks
Almost identical in structure to Vallatisporites vallatus Hacquebard 1957, but distinguished by possessing an ornament of verrucate elements and by the poorly differentiated bizonate cingulum.

Range
Late Devonian to Mississipian; Strunian to Tournaisian; LN to CM biozones (Higgs et al., 1988)

Images

MPK 7311 MPK 7311 Figure 68a
Horton Bluff Formation, Horton Bluff, Nova Scotia, Canada; Tournaisian, VV Biozone, AD Sub-biozone (Utting et al., 1989), Sample P6400, Specimen MPK 7311. Specimen with well-defined inner body and wide differentiated cingulum. Cingulum separated from inner body by well-defined cuniculus. Inner zone of cingulum appears lighter in colour as a result of internal vacuolation. Outer zone more or less uniform in thickness. Distal surface of exoexine bears coarse verrucae, variable in shape and size, normally discrete. Ornament reduced in size and density over cingulum where it may be at least in part replaced by conate elements. Specimen maximum dimension 70 µm.


MPK 7312 MPK 7312 Figure 68b
Horton Bluff Formation, Horton Bluff, Nova Scotia, Canada; Tournaisian, VV Biozone, AD Sub-biozone (Utting et al., 1989), Sample P6400, Specimen MPK 7312. Distal focus showing coarse verrucate ornament on exoexine with tendency for elements to be arranged in a loose concentric manner and showing basal fusion to form short ridges. Ornament reduced on cingulum. Inner part of cingulum shows development of internal vacuolation. Specimen maximum dimension 60 µm.