Pristiograptus dubius dubius ( Suess, 1851 )

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 : 598-600

Pristiograptus dubius dubius ( Suess, 1851)

Figs. 5A, 7A.

1851 Graptolithus dubius sp. nov.; Suess 1851: 115, pl. 9: 5a, b.

1913 Monograptus dubius (Suess, 1850) ; Elles and Wood 1913: 376– 378, text−fig. 247a, b.

1943 Pristiograptus dubius dubius (Suess, 1850) ; Přibyl 1943: 3–4, pl. 1: 4–6.

1952 Pristiograptus dubius dubius (Suess, 1850) ; Münch 1952: 85, pl. 18: 1.

1958 Pristiograptus dubius dubius (Suess, 1850) ; Přibyl 1958: 117.

2000 Pristiograptus dubius dubius (Suess, 1850) ; Radzevičius and Paškevičius 2000: 91–92, pl. 1: 2.

Material.— Ten fragments of rhabdosomes of different preservation from the Kurtuvėnai−161 (1420.5– 1396.9 m) and Parovėja−9 boreholes (651.3– 638 m), Lithuania .

Description.—The ss angle is obtuse. The thecal lips are distinct, not extending onto the ventral wall of the succeeding

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

thecae and ending in the beginning of the ventral wall ( Figs. 5A, 7A). No sicular rings are observed.

Discussion.—The type material of the P. dubius ( Suess, 1851) is flattened and poorly illustrated. It has never been redescribed and refigured. Details of the P. dubius dubius rhabdosome structures are not visible at the type material. The P. dubius morphotype is considered to be P. dubius dubius subspecies, which thecal apertural lip not extending onto the ventral wall of succeeding thecae and ending at the beginning of the ventral wall and without sicular rings.

Stratigraphic and geographic range.—Lower Wenlock Monograptus riccartonensis – M. antennularius Biozones. P. dubius dubius is widespread, having been recorded from all continents.

Pristiograptus dubius pseudodubius ( Bouček, 1932) Figs. 5B, 6A, 7C, D.

1943 Pristiograptus pseudodubius ( Bouček, 1932) ; Přibyl 1943: 8–9, pl. 1:. 1, 3.

1952 Pristiograptus pseudodubius ( Bouček, 1932) ; Münch 1952: 86, pl. 18: 7.

1965 Pristiograptus pseudodubius ( Bouček, 1932) ; Obut et al. 1965: 72, pl. 13: 2.

1965 Pristiograptus pseudodubius ( Bouček, 1932) ; Rickards 1965: 260, pl. 29: 10, text−fig. 2I.

1967 Pristiograptus pseudodubius ( Bouček, 1932) ; Gailite et al. 1967: 243–244, pl. 18: 8, 9, text−fig. 57.

1974 Pristiograptus pseudodubius ( Bouček, 1932) ; Ulst 1974: 108– 109, pl. 11: 1, pl. 12: 1, 2.

2000 Pristiograptus pseudodubius ( Bouček, 1932) ; Radzevičius and Paškevičius 2000: 92–94, pl. 2: 1.

Material.— More then 200 rhabdosomes and fragments from Kurtuvėnai−161 (1351.9– 1328.1 m), Likënai−369 (630.0– 582.1 m), and Parovėja−9 (621.5– 588.6 m) boreholes, Lithuania and Zawada−1 borehole (1590.65– 1584.9 m), Poland .

Description.—The ss angle is obtuse. The thecal apertural lip reaches only the middle of the free ventral wall of the succeeding theca ( Figs. 5B, 7C, D). No sicular rings are observed.

Discussion.—The type material of P. dubius pseudodubius has been described from flattened material and detailed account of the structures of its rhabdosome are not visible. In this work P. dubius pseudodubius is considered to be as dubius morphotype with ss angle obtuse, which thecal apertural lip reaches only the middle of the free ventral wall of the succeeding theca.

Stratigraphic and geographic range.—Wenlock Monograptus belophorus – Cyrtograptus lundgreni Biozones ; P. dubius pseudodubius is widespread, known from all continents.