Pristiograptus sardous ( Gortani, 1922 )

Urbanek, Adam, Radzevičius, Sigitas, Kozłowska, Anna & Teller, Lech, 2012, Phyletic evolution and iterative speciation in the persistent Pristiograptus dubius lineage, Acta Palaeontologica Polonica 57 (3), pp. 589-611 : 604-606

Pristiograptus sardous ( Gortani, 1922)

Figs. 5E, 6B, 8B, D.

1943 Pristiograptus sardous sardous ( Gortani, 1922) ; Přibyl 1943: 14–15, pl. 1: 3, text−fig. 2C.

1943 Monograptus sardous Gortani, 1922 ; Přibyl 1943: pl. 8: 1, text−fig. 9.

1952 Pristiograptus sardous ( Gortani, 1922) ; Münch 1952: 86, pl. 18: 10.

Material.—About 5 rhabdosomes from Zawada−1 borehole (1590.6–1597.7 m), Poland.

Description.—The apertural lips of symmetrically flattened thecae form an acute or right ss angle. Overall, thecal apertures are perpendicular to the rhabdosome axis in the medial and distal parts of the rhabdosome. The λ angle is 30°. There are no sicular rings.

Discussion.—The type material of P. sardous is flattened. P. sardous is P. dubius type Pristiograptus with wide proximal end of rhabdosome.

http://dx.doi.org/10.4202/app.2010.0070

Stratigraphic and geographic range.—Wenlock Cyrtograptus rigidus , Cyrtograptus perneri biozones; Poland, Czech Republic, Italy.

Pristiograptus dubius praelodenicensis subsp. nov. Figs. 5I, 6F, 8A, C, E.

Etymology: From Latin prae, before; supposedly P. dubius praelodenicensis is the ancestor of P. lodenicensis .

Holotype: ZPAL G.44/5, isolated rhabdosome with sicula and 6 thecae, Fig. 8A.

Type locality: Zawada IG−1 borehole, depth 1546.5–1552.7 m, Poland.

Type horizon: Upper Wenlock, Cyrtograptus lundgreni Biozone.

Material.—About 25 rhabdosomes and many fragments from Zawada IG−1 borehole (1546.5–1552.7 m), Poland.

Diagnosis.— ss angle acute. Thecal lips straight and perpendicular to the rhabdosome axis. No sicula rings.

Description.—The rhabdosome is narrow, the proximal end is slightly curved ventrally up to th 4 or th 5. L is more than 30 mm. W is 0.7 mm at th 1, 0.85 mm at th 2, 1 mm at th 3, 1.2 mm at th 4, and 1.2 mm at th 5 level. Wmax is usually 1.5 mm. The interapertural W is 0.65 mm at th 1, 0.7 mm at th 2, 0.8. 5 mm at th 3, 0.9 mm at th 4, and 1 mm at th 5. The ss angle is acute. The thecae are uniform. Thecal lips are perpendicular to the rhabdosomal axis. The th 1 L is 0.9–1 mm, W is 0.3 mm and overlaps th 2 for 1/3 to 1/2 of its length. The λ angle is 29–32°. The sicula is slightly curved ventrally, L is 1.5–2.0 mm, and W 0.25 –0.3 mm at apertural level. The sicular apex is on a level between the middle and the top of th 2. No sicula rings.

Discussion.— P. dubius praelodenicensis subsp. nov. is similar to P. lodenicensis Přibyl, 1943 in having an acute to right β angle.

Stratigraphic and geographic range.—Upper Wenlock, Cyrtograptus lundgreni Biozone , Poland.