Taxonomy Online - Carboniferous spores part I - Species details


Species name
Spelaeotriletes cabotii Utting, Keppie & Giles, 1989

Description
Radial, trilete, camerate miospores. Amb sub-triangular with rounded apices and convex to straight sides. Intexinal inner body poorly defined but when visible conformable in outline with equatorial margin. Inner body occupies 50–80 % of overall diameter. Trilete mark distinct; sutures straight, extending almost to margin of intexine, accompanied by elevated sinuous exoexinal folds up to 2 µm high which extend, decreasing in height to the equatorial margin. Curvaturae rarely visible. Exoexine up to 2 µm thick; infragranulate. Distal surface of exoexine ornamented with closely spaced verrucae with rounded outlines and rounded profiles (up to 5.5 µm in basal diameter, 1–2 µm high); individual verrucae usually surmounted by single small spina or conus (up to 1 µm high and 1 µm in basal diameter). Rare small coni, spinae and baculae may occur between verrucae. Verrucae may coalesce towards distal pole to form rugulae. Small coni, spini and baculae more common in equatorial region than in distal polar region.

Other descriptions
Utting et al.,,1989, p. 133, pl. 5.3, figs. 8–13 and 15

Size
Overall 49(69)93 µm. Inner body 36(46)65 µm

Remarks
Smaller and with more densely distributed ornament of verrucae than Spelaeotriletes pretiosus (Playford) Neves & Belt 1970. In S. pretiosus, the verrucose ornament shows no tendency to form rugulae near the distal pole. S. balteatus differs in possessing an ornament of small simple spinae.

Range
Mississippian; Tournaisian to ?Visean (Utting et al.,1989)

Images

MPK 7738 MPK 7738 Figure 53a
Horton Bluff Formation, Nova Scotia, Canada; Tournaisian, VV Biozone, SC Sub-biozone (Utting et al., 1989), Sample P2618, Specimen MPK 7738. Equatorial focus showing outline of thin walled inner-body. Note apparent thickening at the equatorial margin, which may be a combination of exoexine wall thickness and feature coincident with narrow curvaturae imperfectae. Exoexine ornament variable, consisting of verrucae with smaller numbers of grana and coni. Specimen maximum dimension 70 µm.


MPK 7739 MPK 7739 Figure 53b
Horton Bluff Formation, Nova Scotia, Canada; Tournaisian, VV Biozone, SC Sub-biozone (Utting et al., 1989), Sample P2618, Specimen MPK 7739. Showing trilete rays extending to the equatorial margin of inner body. Thickening near equator not always coincident with equatorial margin, suggesting possible interpretation as curvaturae. Ornament dominated by fine coni and grana. Specimen maximum dimension 80 µm.