Pristiograptus dubius parvus Ulst, 1974

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 : 600

Pristiograptus dubius parvus Ulst, 1974

Figs. 5J, 6H, 10C, D .

1974 Pristiograptus parvus sp. nov.; Ulst 1974: 111–113, pl. 12: 43, pl. 11: 5.

1991 Pristiograptus dubius parvus Ulst, 1974 ; Jaeger 1991: 316–318, pl. 25: 2–6, 8.

1996 Pristiograptus dubius “ parvus ” Ulst, 1974 ; Gutierrez−Marco et al. 1996: 660, pl. 1: 1–3.

1998 Pristiograptus parvus Ulst, 1974 ; Kozłowska−Dawidziuk et al. 1998: 99, pl. 1G.

1999 Pristiograptus parvus Ulst, 1974 ; Kozłowska−Dawidziuk 1999: 356, fig. 3a.

2000 Pristiograptus parvus Ulst, 1974 ; Radzevičius and Paškevičius 2000: 95–96, pl. II: 2, 3; pl. VI: F.

2001 Pristiograptus parvus Ulst, 1974 ; Kozłowska−Dawidziuk et al. 2001: 159–161, fig. 8: 11–13, fig. 9: 6–8.

2004 Pristiograptus parvus Ulst, 1974 ; Porębska et al. 2004: 276, fig. 3R.

2010 Pristiograptus parvus Ulst, 1974 ; Radzevičius et al. 2010: 56, fig. 3B, D.

Material.— About 100 rhabdosomes and fragments from the Kurtuvėnai−161 (1323.2– 1321.1 m), Parovėja− 9538 m), Šiupyliai−69 (1004– 1000.8 m) boreholes, Lithuania and Bartoszyce IG−1 borehole (1660– 1657.8 m), Poland .

Description.—The rhabdosome is straight, sometimes slightly curved to the ventral side, the ss angle is obtuse ( Fig. 5J). The first theca begins at the level of the sicula aperture ( Fig. 6H). P. parvus is like a small version of P. dubius pseudodubius .

Discussion.—The type of P. parvus Ulst, 1974 was described using non−isolated, flattened material. This species is specific having very small rhabdosome.

Stratigraphic and geographic range.— P. parvus Biozone , East European Platform ( Poland, Latvia, Lithuania, Sweden), Czech Republic, Germany, Spain, Canada.

Figures

Fig. 10. SEM micrographs of two Homerian (Wenlock) graptolite Pristiograptus forms. A, B. Pristiograptus dubius paezerensis subsp. nov., mature rhabdosomes; Cyrtograptus lundgreni Biozone. A. ZPAL G.44/17, Bartoszyce IG−1 borehole, Poland, depth 1663.2 m. B. ZPAL G.44/19, Zawada borehole, Poland, depth 1555.9–1562 m. C, D. Pristiograptus dubius parvus Ulst, 1974 growing rhabdosomes, Bartoszyce IG−1 borehole, Poland, depth 1660.7 m; Pristiograptus parvus Biozone. C. ZPAL G.44/25. D. ZPAL G.44/26.