Taxonomy Online - Carboniferous spores part I - Species details


Species name
Reticulatisporites carnosus (Knox) Neves, 1964

Description
Radial, trilete, cingulate miospores. Amb broadly rounded triangular to subcircular, margin usually smooth, but occasionally undulate to uneven or highly involute. Trilete mark distinct, sutures straight, simple or with low narrow labra, extending to inner margin of the cingulum. Intexine relatively thin forming subcircular to rounded triangular inner body. Exoexine extended equatorially to form differentially thickened cingulum consisting of three zones, each varying from 5 to 17 µm in width. The inner thickened zone is broader and more prominent than the outer marginal thickened zone, which is commonly reduced or discontinuous. The thinner median zone may be reduced to a mere line but in other specimens may be of significant width. Radially orientated thickenings may be present on the distal surface and take the form of a Y-shaped structure attached to the cingulum in the inter-radial positions. Faint proximal thickenings may arise from the radial positions but they scarcely extend poleward beyond the inner thickened zone of the cingulum.

Other descriptions
Knox, 1950, p. 329, p1. 19, fig. 290. Smith and Butterworth, 1967, pp. 220–221, pl. 14, figs. 11–12

Size
Overall equatorial diameter 67(84)90 µm

Remarks
Distinguished from other species assigned to the genus by the absence of any elaborate pattern of distal thickenings. In some specimens assigned to this species a distal pattern of thickenings comparable to those in Reticulatisporites polygonalis (Ibrahim) Neves 1964 may occur, in which case R. carnosus is distinguished by the discontinuous nature of the outermost thickened zone of its cingulum.

Range
Mississippian to Pennsylvanian; late Visean to Bashkirian [early Langsettian]; NC to SS biozones (Clayton et al., 1977; Smith and Butterworth, 1967)

Images

MPK 7019 MPK 7019 Figure 43a
Diddup Borehole, 7.20 m, Scotland; Bashkirian [early Langsettian], SS Biozone, Sample MPA 4597, Specimen MPK 7019. Equatorial focus of specimen with polygonal equatorial outline but rounded triangular–subcircular inner body. Trilete mark distinct, open, sutures extend to outer margin of inner body. Cingulum thick and weakly trizonate. Minor thickenings developed on proximal surface of cingulum extending from equatorial margin to ends of trilete rays. Specimen maximum dimension 72 µm.


MPK 7024 MPK 7024 Figure 43b
Diddup Borehole, 7.20 m, Scotland; Bashkirian [early Langsettian], SS Biozone, Sample MPA 4579, Specimen MPK 7024. Trilete mark open but with sutures which appear to extend to equatorial margin of body. Well-developed differentially thickened cingulum with relatively wide thickened inner zone, narrow thinner median zone and discontinuosly developed thicker outer zone. Radial thickenings well developed on proximal surface, extending from equatorial margin to join up with ends of trilete rays. Specimen maximum dimension 82 µm.