TY - JOUR
T1 - Morphology and reconstruction of the retiolitines
T2 - Silurian graptolites of the Paraplectograptus lineage (Graptolithina)
AU - Bates, Denis E.B.
AU - Kirk, Nancy H.
AU - Kozlowska, Anna
N1 - Publisher Copyright:
© 2023 Elsevier Masson SAS. All rights reserved.
PY - 2023/2/6
Y1 - 2023/2/6
N2 - The long ranging Silurian retiolitines belonging to the Paraplectograptus lineage (Spirograptus turriculatus to Cyrtograptus/lundgreni Biozone), represented by the genera Paraplectograptus Bouček & Münch, 1952 and Pseudoplectograptus Obut & Zaslavskaya, 1983 are described in detail based on well preserved, three-dimensional material from the Canadian Arctic and Poland. For the first time, reconstructions of their structure are attempted, and comparisons are made with the related genera, Stomatograptus Tullberg, 1883 and Retiolites Barrande, 1850. Ultrastructural details vary somewhat between the genera: the bandaging on the Paraplectograptus lineage and Pseudoplectograptus has a characteristic pustulose ornament, while that of Retiolites and Stomatograptus shows a surface of longitudinal striations. Prosicular preservation is generally incomplete, represented merely by the prosicular apex and prosicular rim. The thecal part of the Paraplectograptus and Pseudoplectograptus tubaria (rhabdosomes) possesses transverse rods, connecting rods, lateral apertural rods and lips. The ancora sleeve lists are variably developed but lack a dorsal/zigzag list, which is present in Stomatograptus and Retiolites. The Paraplectograptus lineage appears to mark an intermediate stage in the evolution of the retiolitines, from the early Silurian forms, with strong thecal and ancora sleeve frameworks (e.g. Retiolites, Stomatograptus), to late Silurian descendants with strong ancora sleeves, minimal thecal frameworks and pustular ornament, with no transverse rods.
AB - The long ranging Silurian retiolitines belonging to the Paraplectograptus lineage (Spirograptus turriculatus to Cyrtograptus/lundgreni Biozone), represented by the genera Paraplectograptus Bouček & Münch, 1952 and Pseudoplectograptus Obut & Zaslavskaya, 1983 are described in detail based on well preserved, three-dimensional material from the Canadian Arctic and Poland. For the first time, reconstructions of their structure are attempted, and comparisons are made with the related genera, Stomatograptus Tullberg, 1883 and Retiolites Barrande, 1850. Ultrastructural details vary somewhat between the genera: the bandaging on the Paraplectograptus lineage and Pseudoplectograptus has a characteristic pustulose ornament, while that of Retiolites and Stomatograptus shows a surface of longitudinal striations. Prosicular preservation is generally incomplete, represented merely by the prosicular apex and prosicular rim. The thecal part of the Paraplectograptus and Pseudoplectograptus tubaria (rhabdosomes) possesses transverse rods, connecting rods, lateral apertural rods and lips. The ancora sleeve lists are variably developed but lack a dorsal/zigzag list, which is present in Stomatograptus and Retiolites. The Paraplectograptus lineage appears to mark an intermediate stage in the evolution of the retiolitines, from the early Silurian forms, with strong thecal and ancora sleeve frameworks (e.g. Retiolites, Stomatograptus), to late Silurian descendants with strong ancora sleeves, minimal thecal frameworks and pustular ornament, with no transverse rods.
KW - Graptolithina
KW - Paraplectograptus
KW - reconstruction
KW - Retiolitinae
KW - Silurian
KW - tubarium (rhabdosome) morphology
UR - http://www.scopus.com/inward/record.url?scp=85169081910&partnerID=8YFLogxK
U2 - 10.5852/cr-palevol2023v22a4
DO - 10.5852/cr-palevol2023v22a4
M3 - Article
SN - 1631-0683
VL - 22
SP - 45
EP - 57
JO - Comptes Rendus Palevol
JF - Comptes Rendus Palevol
IS - 4
ER -