Tubarium construction in the Retiolitinae (Graptolithina, Axonophora)

Maletz, Jörg

doi:10.1016/j.earscirev.2022.104131

Cited by 2 publications

(7 citation statements)

References 38 publications

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“…The specimen clearly shows similarities to a Paraplectograptus with few lists, but a definite identification is impossible. If this specimen represents Paraplectograptus, the origin of the genus would be found much earlier than suggested elsewhere in this paper, filling part of the gap in the Telychian to early Sheinwoodian discussed by Maletz (2022). Bates et al (2023) based their interpretation of the early evolution of the Retiolitinae and the phylogenetic connection on the genera Retiolites and Stomatograptus entirely on this possible early record of Paraplectograptus.…”

Section: Introductionmentioning

confidence: 50%

“…1D), but the latter (Fig. 1f) indicated a theoretical zigzag homologue of the reverse zigzag lists of Retiolites, suggesting that the transverse lists in Maletz (2022) may include parts of the lateral apertural lists on the reverse side of the tubarium.…”

Section: Previous Interpretationsmentioning

confidence: 96%

“…Kozłowska-Dawidziuk 1990;Lenz, 1993). Eisenackograptus eisenacki (Obut and Sobolevskaya, 1965) possesses an undulating, reticulated ventral thecal wall that reaches deep into the tubarium at least in the first thecal pair (Maletz 2022, fig. 3C) and does not bear a geniculum (Fig.…”

Section: Reticulate Ventral Thecal Wallsmentioning

confidence: 99%

“…Considerably diverging interpretations have been published in recent years regarding the genera Paraplectograptus and Pseudoplectograptus and their potential evolutionary relationships to the robust retiolitine genera Retiolites and Stomatograptus. Lenz et al (2018) and Maletz (2022Maletz ( , 2023a considered Paraplectograptus and Pseudoplectograptus to be synonymous as they possessed no definitive constructional characters to show a sufficient separation of the included species, but Kozłowska-Dawidziuk (1995, 2004 and Bates et al (2023, p. 52) separated the genera based largely on their tubarium dimensions ('Pseudoplectograptus has a more robust and wider rhabdosome whereas that of Paraplectograptus is slender and parallel-sided'). Bates et al (2023) supported the long-held view of a long ranging genus Paraplectograptus from the lower Telychian (Llandovery) Spirograptus turriculatus Biozone to the lower Homerian (Wenlock) Cyrtograptus lundgreni Biozone (see also Lenz and Melchin 1997, fig.…”

Section: Introductionmentioning

confidence: 99%

“…Lenz and Melchin 1987;Melchin et al 2017). Maletz (2022) indicated a more limited range of the genus from the Sheinwoodian (Wenlock) Monograptus riccartonensis Biozone to the Cyrtograptus lundgreni Biozone, rejecting the poorly known ?Paraplectograptus sp. of Melchin et al (2017) as a member of the genus Paraplectograptus.…”

Section: Introductionmentioning

confidence: 99%

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The identity of the Silurian retiolitine genera Paraplectograptus and Sagenograptoides (Graptoloidea, Retiolitinae)

Maletz

2023

Palaeobio Palaeoenv

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The genus Paraplectograptus includes a small number of retiolitine species with an identical development of the main thecal and ancora sleeve lists. A complete virgella-virga-nema development with connecting lists is formed on the obverse side of the tubarium, while the only thecal lists on the reverse side are the lateral apertural lists, connected through the pleural lists of the ancora sleeve. Obverse and reverse sides of the tubarium are connected by the thecal lips on the ventral sides. The characteristic zigzag thecal lists of the reverse side of many early retiolitines are not present in the genus. The development and extent of the reticular ancora sleeve lists on the obverse and reverse sides of the tubarium are quite variable and range from lacking entirely to dense. The genus Pseudoplectograptus is regarded as a junior synonym of Paraplectograptus. Pseudoplectograptus sagenus is transferred to the genus Sagenograptoides. Its type species ‘Sagenograptoides arctos’ was known only from small, immature or fragmentary specimens of the associated Sagenograptoides sagenus. This species bears a characteristic reticulum on the ventral thecal walls, not found in the genus Paraplectograptus, but which is present in other Cyrtograptus lundgreni Biozone retiolitines.

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Section: Introductionmentioning

confidence: 50%

Section: Previous Interpretationsmentioning

confidence: 96%

Section: Reticulate Ventral Thecal Wallsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The identity of the Silurian retiolitine genera Paraplectograptus and Sagenograptoides (Graptoloidea, Retiolitinae)

Maletz

2023

Palaeobio Palaeoenv

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The tubarium construction in Holoretiolites, Neogothograptus and related taxa (Graptolithina, Retiolitinae): clues to their astogeny and species identification

Maletz

2023

Palaeobio Palaeoenv

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The Homerian (Wenlock) to Ludfordian (Ludlow), late Silurian, retiolitine genera Neogothograptus and Holoretiolites and their relatives are revised. These are often considered as the youngest and smallest retiolitine taxa, characterised by a finite growth indicated by the appendix, leading to the extinction of the clade. The tubarium construction of the genera is analysed and compared, showing the loss of the pleural and parietal lists in Holoretiolites and the development of a central zigzag construction on the obverse and reverse sides of the tubarium. This construction is not homologous to similar constructions in earlier retiolitines, as it is based on the modification of the lateral apertural lists. It is also found in the closely related Semiplectograptus and Plectodinemagraptus. Useful details to understand the astogeny of these taxa include the development of the reticulum, the genicular processes and the outer ancora. These features are described for the first time for most species. Details of the outer ancora and its construction in the genus Neogothograptus are still poorly understood. Holoretiolites helenaewitoldi is synonymised with Holoretiolites atrabecularis. Holoretiolites manckoides is transferred to Semiplectograptus.

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Tubarium construction in the Retiolitinae (Graptolithina, Axonophora)

Cited by 2 publications

References 38 publications

The identity of the Silurian retiolitine genera Paraplectograptus and Sagenograptoides (Graptoloidea, Retiolitinae)

The identity of the Silurian retiolitine genera Paraplectograptus and Sagenograptoides (Graptoloidea, Retiolitinae)

The tubarium construction in Holoretiolites, Neogothograptus and related taxa (Graptolithina, Retiolitinae): clues to their astogeny and species identification

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