Development of the graptoloid rhabdosome

Cooper, Roger A.; Fortey, Richard A.

doi:10.1080/03115518308619621

Cited by 30 publications

(27 citation statements)

References 16 publications

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“…For example, extremely elongate metathecal folds were also found in Llandovery Lapworthograptus knockensis group (see Elles and Wood 1913;Rickards 1970;Zalasiewicz 1995), which are very similar to Sinograptus in most respects except the adpressed metathecal folds. The paired lateral lobes similar to those in Tylograptus, and genicular hoods similar to that in Sinograptus, also occur in Llandovery Pribylograptus (Rickards and Rushton 1968;Rickards et al 1977;Loydell 1991;Lukasik and Melchin 1997).…”

Section: T H E T H E C a E O F T Y L O G R A P T U S A N D S I N O G mentioning

confidence: 99%

“…th1 1 dicalycal). However, it has been widely accepted that isograptid-type proximal development is a primitive character, whereas artus-type is a derived character Fortey 1982, 1983;Fortey and Cooper 1986;Fortey and Owens 1987). Since we know now that Tylograptus and Sinograptus have isograptid development, it is unlikely that sinograptids were derived from any ancestor with th1 1 dicalycal.…”

Section: R E L a T I O N S W I T H O T H E R G R O U P Smentioning

confidence: 99%

“…The stipe reduction series is in parallel with the lineages of dichograptids lacking prothecal folds. However, this proposal does not take proximal development and thecal apertural structure into account suf®ciently and therefore is not acceptable on present knowledge (see Mu et al 1979;Fortey and Cooper 1986;Williams and Stevens 1988).…”

Section: R E L a T I O N S W I T H O T H E R G R O U P Smentioning

confidence: 99%

“…Superfamily DICHOGRAPTOIDEA Lapworth, 1873 (sensu Fortey andCooper, 1986) Family SINOGRAPTIDAE Mu, 1957 Genus TYLOGRAPTUS Mu, 1957, emend. Type species. Tylograptus regularis Mu, 1957;Ningkuo Formation, Changshan, Zhejiang;Darriwilian. Emended diagnosis.…”

Section: S Y S T E M a T I C P A L A E O N T O L O G Ymentioning

confidence: 99%

“…Taking D. callotheca sensu stricto as type species, Kozlowski (1954) erected Holmograptus, and reiterated the proximal development as`bi®dus' stage of dichograptid type, as did Bell (1960). The`bi®dus' development type has subsequently been renamed the artus type (Cooper and Fortey 1982) following the description of the type specimen of D. bi®dus, which shows a different development. Jaanusson (1960) re-examined type specimens of Holmograptus lentus (To Èrnquist, 1911), and some additional, partially pyritized material from southern Sweden.…”

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confidence: 99%

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The Proximal Development and Thecal Structure of the Ordovician Graptolites Tylograptus and Sinograptus

Zhang

Fortey

2001

Palaeontology

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ABSTRACT. A study of pyritic and three-dimensional specimens of sinograptids from the early Middle Ordovician Ningkuo Formation of western Zhejiang Province, south-east China, indicates that the proximal development of both Tylograptus and Sinograptus is of modi®ed isograptid type. The thecal apertures of the two genera are reconstructed and display a complex morphology more typical of stratigraphically younger graptoloids. Because of differences in its prothecal folds and thecal apertures Tylograptus is distinguished from Holmograptus and regarded as a valid genus. In Sinograptus, a tongue-shaped structure, and constriction of the thecal tube after the metathecal fold, are illustrated for the ®rst time. The proximal development and thecal structures of Tylograptus and Sinograptus imply a possible origin of sinograptids from earlier didymograptids or sigmagraptids. Four species, Tylograptus intermedius, T. globiformis, Sinograptus typicalis and S. rastritoides, are revised.

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Section: T H E T H E C a E O F T Y L O G R A P T U S A N D S I N O G mentioning

confidence: 99%

Section: R E L a T I O N S W I T H O T H E R G R O U P Smentioning

confidence: 99%

Section: R E L a T I O N S W I T H O T H E R G R O U P Smentioning

confidence: 99%

Section: S Y S T E M a T I C P A L A E O N T O L O G Ymentioning

confidence: 99%

mentioning

confidence: 99%

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The Proximal Development and Thecal Structure of the Ordovician Graptolites Tylograptus and Sinograptus

Zhang

Fortey

2001

Palaeontology

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References

2017

Graptolite Paleobiology

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Ordovician graptolite evolutionary radiation: a review

2006

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Based on the global graptolite genera and higher rank taxa, we propose three radiation stages through the Ordovician. The isograptid type of development is present within anisograptids predominating in the Tremadocian. Thus, the evolutionary radiation of the Anisograptid fauna from Tremadocian is proposed as the beginning of the Ordovician graptolite radiation. The second graptolite radiation event is the radiation of the Dichograptid fauna, which began from the T. fruticosus Biozone. The third radiation event, the radiation of Diplograptid fauna began immediately after that of the dichograptids. This radiation includes the peak in total diversity of all the Ordovician graptoloids in the Nemagraptus gracilis Biozone. The radiation extended through the Sandbian and Katian and then was interrupted by a major extinction during the early Hirnantian. Thus, the Ordovician graptolite radiation events coincide with those of the three graptolite faunas proposed by Bulman. The distribution and expansion of the Ordovician graptolites in South China may exemplify the graptolite origination pattern, which begins from the slope belt and expanded into both the shelf and oceanic zones.

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Development of the graptoloid rhabdosome

Cited by 30 publications

References 16 publications

The Proximal Development and Thecal Structure of the Ordovician Graptolites Tylograptus and Sinograptus

The Proximal Development and Thecal Structure of the Ordovician Graptolites Tylograptus and Sinograptus

References

Ordovician graptolite evolutionary radiation: a review

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