Hostname: page-component-77c89778f8-m8s7h Total loading time: 0 Render date: 2024-07-20T23:29:00.297Z Has data issue: false hasContentIssue false
  • English
  • Français

Virgellar meshworks and sicular spinosity in Llandovery graptoloids

Published online by Cambridge University Press:  01 May 2009

R. B. Rickards  and
T. N. Koren'
R. B. Rickards
Affiliation:
Sedgwick MuseumCambridge CB2 3EQEngland
T. N. Koren'
Affiliation:
T. N. Koren' VSEGEILenigrad V-26U.S.S.R
Get access Rights & Permissions [Opens in a new window]

Summary

Orthograptus obuti sp.nov. and Orthograptus insectiformis Nicholson are shown to exhibit a complex proximal meshwork developed from a much-divided virgella which closely resembles retiolitid clathrial and lacinial networks. The virgellar meshworks tend to enclose the rhabdosome, at least for the first few thecal pairs, and may support a tenuous periderm. This kind of virgellar complexity is contrasted with a newly discovered form of sicular spinosity represented by the species Glyptograptus (Pseudoglyptograptus) tabukensis sp.nov. and G. (P.) rhayaderensis sp.nov

Type
Articles
Information
Geological Magazine , Volume 111 , Issue 3 , May 1974 , pp. 193 - 204
Copyright
Copyright © Cambridge University Press 1974

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bulman, O. M. B. 1957. In Ladd, H. S. (Ed.): Treatise on Marine Ecology and Paleoecology. 2. Paleoecology. Mem. geol. Soc. Amer. 67.Google Scholar
Bulman, O. M. B. 1964. Lower Palaeozoic plankton. Q. JI geol. Soc. Lond. 120, 455–76.Google Scholar
Bulman, O. M. B. 1970. In Teichert, C. (Ed.): Treatise on Invertebrate Paleontology.Part V. Graptolithina, with sections on Enteropneusta and Pterobranchia (2nd edition), i–xxxii, 1–63. Geol. Soc. Amer. & Univ. Kansas Press.Google Scholar
Bulman, O. M. B, & Rickards, R. B. 1968. Some new diplograptids from the Llandovery of Britain and Scandinavia. Palaeontology, 11, 1–15.Google Scholar
Elles, G. L. & Wood, E. M. R. 1901–1918. A Monograph of British Graptolites. Edited by Lapworth, C. Palaeontogr Soc. [Monogr.], pls. 1–11, i–clxxi, 1–539.Google Scholar
Hutt, J. E., Rickards, R. B. & Skevington, D. 1970. Isolated Silurian graptolites from the Bollerup and Klubbudden stages of Dalarna, Sweden. Geologica et Paleontologica, 4, 1–23.Google Scholar
Lapworth, C. 1873. On an improved classification of the Rhabdophora. Geol. Mag. 10, 500–4, 555–60.Google Scholar
Lapworth, C. 1875. In Hopkinson, J. & Lapworth, C. 1875. Description of the graptolites of the Arenig and Llandeilo rocks of St Davids. Q. JI geol. Soc. Lond. 31, 631–72.Google Scholar
Nicholson, H. A. 1869. On some new species of graptolites. Ann. Mag. nat. Hist. 4, 231–42.CrossRefGoogle Scholar
Obut, A. M., Sobolevskaya, R. F. & Merkuryeva, A. P. 1968. Graptolity Ilandoveri v kernakh burovykh skvazhin noryl'skogo rayona. Akad. Nauk SSR. Otdel. Inst. Geol. Geofiz. 1–136. (In Russian.)Google Scholar
Rickards, R. B. 1970. The Llandovery (Silurian) Graptolites of the Hougill Fells, Northern England. Palaeontogr. Soc. [Monogr.] 123, 1–108.Google Scholar
Rickards, R. B. 1972. Climacograptus scalaris (Hisinger) and the Subgenus Glyptograptus (Pseudoglyptograptus). Geol. För. Förh. 94, 271–80.Google Scholar
Stein, W. 1965. Stratigraphische und paläontologioche Untersuchungen im Silur des Frankenwaldes. Neues Jb. Geol. Paläont. Abh. 121, 111–200.Google Scholar
Toghill, P. 1968. The graptolite assemblages and zones of the Birkhill Shales (Lower Silurian) at Dobb's Linn. Palaeontology 11, 654–68.Google Scholar