Taxonomy Online - Carboniferous spores part I - Species details


Species name
Hystricosporites multifurcatus (Winslow) Mortimer & Chaloner, 1967

Description
Radial, trilete, acamerate miospores-megaspores. Amb, excluding projecting ornament, rounded triangular with straight or slightly convex sides and rounded apices. Proximal surface flattened, low, pyramidal; distal surface inflated, hemispherical. Trilete mark distinct, sutures straight, extending at least four-fifths of spore radius, accompanied by elevated flexuous folds of the exoexine which form an apical prominence up to 50 µm high. Folds decrease in height toward the equator. No obvious indication of separation of exine layers. Exine thick, surface scabrate, ornamented with long, parallel-sided or gently tapering processes which have expanded bases. Fusion between adjacent processes may occur at their bases and in the lower parts of the processes. Shafts of the processes appear hollow and have finely striated surfaces. Process termini are solid and characteristically ornamented with up to five recurved spinae producing a grapnel-like appearance. Processes 70–120 µm long, and excluding the expanded base, up to 10 µm wide. Recurved spinae creating grapnel terminations 1–5 µm long and 1–1.5 µm wide. Processes appear to be developed over entire distal surface with concentration in the equatorial region; 8–15 elements project at the equatorial margin. Some specimens show weak indication of ill-defined internal body.

Other descriptions
Winslow, 1962, p. 52, pl. 11, figs. 4–5; p1. 12, fig. 5, p1. 22, fig. 15

Size
Overall equatorial diameter excluding projecting ornament 90(173)233 µm

Remarks
The distinctive ‘grapnel’ termini of its long slender processes distinguishes H. multifurcatus from all other taxa assigned to the genus. Mid and Late Devonian species of Hystricosporites have characteristic radially orientated ribs within the contact areas of the proximal surface; these are not present in H. multifurcatus.

Range
Devonian to Mississippian; Strunian to early Visean (from unpublished information).

Images

MPK 7267 MPK 7267 Figure 23a
Bedford Shale, Big Walnut Creek, Sudbury, Ohio, USA; Late Devonian, Strunian, LL Biozone, Sample SB3, Specimen MPK 7267. Lateral compression showing almost flat proximal surface and inflated distal hemisphere. Proximal surface has elevated apical prominence formed by folds of the exoexine protecting the trilete mark. Surface of body scabrate. Specimen has prominent ornament of long processes that terminate in distinctive multifurcate appendages (see detail). Some processes appear to be bifurcate, while others split into up to five recurved spinae. Specimen maximum dimension, excluding projecting ornament, 131 µm.


MPK 7267_detail MPK 7267_detail


MPK 7268 MPK 7268 Figure 23b
Bedford Shale Big Walnut Creek, Sudbury, Ohio, USA; Late Devonian, Strunian, LL Biozone, Sample SB3, Specimen MPK 7268. Specimen maximum dimension, excluding projecting ornament, 94 µm.