Semigothograptus, Kozłowska, Anna, 2016

Kozłowska, Anna, 2016, A new generic name, Semigothograptus, for Gothograptus? meganassa Rickards & Palmer, 2002, from the Silurian post- lundgreni Biozone recovery phase, and comparative morphology of retiolitids from the lowermost upper Homerian (upper Wenlock), Zootaxa 4208 (6), pp. 534-546 : 536

Genus Semigothograptus new genus

Etymology. The generic name Semigothograptus is derived from semi (half in Latin) and Gothograptus Frech, 1897 indicating some similarity to the genus Gothograptus .

Type and only species. Gothograptus ? meganassa ( Rickards & Palmer, 2002)

Type locality. Aston Piggot , Long Mountain , Shropshire, UK; material deposited in the Sedgwick Museum, Cambridge ( Rickards & Palmer 2002).

Diagnosis. Tubarium widening gradually from proximal end, nema free. Ancora umbrella simple, a pair of large looping meshes on each side of tubarium. Proximal ventral orifices of triangular shape; lateral orifices kidney-shaped. Ventral wall represented by mid-ventral lists, lips, genicular list, and long lateral apertural rods convex towards the centre of lateral wall, which become distinctly sigmoidal the more distal they are. Oblique clathrial lists on lateral walls.

Remarks. The new genus Semigothograptus has a free nema, which therefore does not affect the pattern of the lateral wall, whereas Gothograptus , to which the described species was tentatively designated by Rickards and Palmer, has the nema connected to the lateral (obverse) side of the tubarium ( Fig. 1 A). The long lateral apertural rods, convex towards the centre of lateral wall, are unique to Semigothograptus .

Figures

FIGURE 1. Tubaria of A – C. Gothograptus nassa Holm, 1890 and D. Semigothograptus meganassa (Rickards & Palmer, 2002) from dubius / nassa Biozone, Bartoszyce IG- 1 drill core, Poland. A. Gothograptus nassa, obverse view of mature tubarium with destroyed distal end, long morphotype, ZPAL G. 54 / 5, 1655.8 m, B. latero-ventral view of mature tubarium with appendix, short morphotype, ZPAL G. 54 / 8, 1658.8 m, C. long appendix, ZPAL G. 54 / 10, 1656.8 m. D. Semigothograptus meganassa, obverse view, ZPAL G. 54 / 1, 1649.2 m, uppermost part of dubius / nassa Biozone.