Taxonomy Online - Carboniferous spores part I - Species details


Species name
Spelaeotriletes arenaceus Neves & Owens, 1966

Description
Radial, trilete, camerate miospores. Amb convexly triangular, or subcircular to oval when secondarily folded. Trilete mark distinct; sutures simple, straight, extending to equatorial margin of spore body, commonly accompanied by narrow elevated folds of the exoexine which extend, decreasing in height, almost to the equatorial margin of the spore, where they fuse into the invaginated narrow ridge of the curvaturae. Curvaturae coincident with equatorial margin over most of their length. Intexine thin, forms indistinct inner body. Intexine thin, attached to exoexine, only in the region of the proximal surface, forms saccus-like structure. Exoexine surface infrapunctate, bears a composite ornament of small squat bacula, rounded and flat topped verrucae, pila, and pointed and truncated coni; elements 1–2 µm high and 1–2.5 µm in basal diameter. Ornament variably distributed but mainly on distal surface with minor encroachment onto proximal surface in the radial positions. Elements normally discrete but occasionally showing basal fusion with adjacent elements to create short irregular ridges.

Other descriptions
Neves and Owens, 1966, p. 345–346, pl. 2, figs. 1–3

Size
Overall equatorial diameter 82–144 µm. Diameter of inner body 44–90 µm

Remarks
Spelaeotriletes arenaceus is distinguished from S. triangulus Neves & Owens 1961 and S. balteatus (Playford) Higgs 1975 by the fine character of the ornamentation of the exoexine. S. balteatus is also smaller.

Range
Mississippian to Pennsylvanian; late Visean to Bashkirian [early Langsettian]; NM to SS biozones (Clayton et al., 1977)

Images

MPK 7147 MPK 7147 Figure 51a
Shales above Mousegill Marine Band, Crag House Gill, Stainmore, Cumbria, England; Bashkirian [Kinderscoutian], KV Biozone, Sample CHG 1, Specimen MPK 7147. Rounded triangular camerate miospore. Intexine forms poorly defined rounded triangular inner body. Trilete mark distinct, sutures extend to margin of inner body, accompanied by elevated exoexinal folds that extend to equatorial margin where they fuse with invaginated equatorial thickening, which may represent curvaturae. Exoexine densely ornamented with small coni, grana and baculae, some of which show basal fusion between adjacent elements to form short irregular ridges. Specimen maximum dimension 122 µm.


MPK 7149 MPK 7149 Figure 51b
Shales below Hurlet Limestone, Hurlet Borehole, 37.50 m, Scotland; Visean, VF Biozone, Sample MPA 9147, Specimen MPK 7149. Note evidence on uppermost trilete ray to indicate that exoexinal folds accompanying trilete sutures merge in the radial position with narrow curvatural ridge just inside the equatorial margin. Curvaturae extend laterally and become coincident with the limbate equatorial margin. Specimen maximum dimension 110 µm.