Radiolarian Micropalaeontology: Morphology and Taxonomy Professor Simon K. Haslett Centre for Excellence in Learning and Teaching 23 rd February 2010

Introduction Radiolaria are classified as a Subclass of Sarcodine Protozoa (single-celled). Three Orders: Acantharia, Phaeodaria, and Polycystina (the latter is the most significant in micropalaeontology). Secrete silica (SiO 2 ) tests (cf. shells). They are marine holoplankton.

Polycystine Radiolaria Polycystine Radiolaria comprise two major Suborders: 1) Spumellaria2) Nassellaria. Spine Cortical Shell with Pores Inner Medullary Shell(s) connected to the Cortical Shell by radial bars or beams Cephalis Thorax Abdomen Post-abdominal segments

Spumellarian Morphology 1 a) Cortical shell only, usually with pores. b) Medullary and cortical shells and spines. c) Shells and polar spines that are connected by an external circular ring. d) Medullary and a constricted cortical shell with polar caps.

Spumellarian Morphology 2 a) discoidal and lenticular forms, with medullary and cortical shells, sometimes with protruding spines. b) spongy shells are common in a number of different forms. c) gated forms occur due to encircling girdles.

Nassellarian Morphology 1 Spicule –Apical spine –Sagittal ring –Vertical spine –Cephalis (elementary) –Median bar (short) –Lateral spine (vestige) –Dorsal spine (vestige)

Nassellarian Morphology 2 a) cephalis only (here with some feet). b) cephalis and thorax only (here with large cephalic horns and abdominal feet). c) cephalis, thorax, and abdomen only (with horn). d) as in c) plus one post- abdominal segment e) as in d) plus three or four post- abdominal segments

Other Morphological Features a) perforate plate pores. b) spongy pores.c) rectangular (left) and polygonal or honey-combed (right) pores. d) circular pores. e) cephalic tube. f) peristome around the aperture. g) teeth around the aperture.

Major Taxonomic Groups There are numerous taxonomic groups and thousands of species, but their classification has proved problematic to generations of taxonomists. Examples of a number of the most frequently encountered Quaternary Spumellarian and Nassellarian taxa are:

Collosphaerids

SaturnalinsCubosphaerins

ArtiscidsPhacodiscids

SpongopylinsSpongasterins

Dictyocorins

Spongurins

PylonidsAcanthodesmids

Carpocanids

Eucyrtidins

Theocalyptrins

Plectopyramins

Pterocorids

Artostrobids

Cannobotryids

Summary This presentation included: –An introduction to Polycystine Radiolaria. –General morphology of Spumellarian and Nassellarian Polycystine Radiolaria. –An introduction to radiolarian taxonomic forms common in Quaternary studies. –A guide to further reading on the topic.

Further Reading Anderson, O. R., Radiolaria. Springer-Verlag, New York. Armstrong, H. A., Brasier, M. D., Microfossils (2 nd Ed). Blackwell, Oxford.Microfossils Casey, R. E., Radiolaria. In: Lipps, J. H. (ed.) Fossil Prokaryotes and Protists. Blackwell, Oxford, pp Nigrini, C., Moore, T. C. Jr, A Guide to Modern Radiolaria. Cushman Foundation for Foraminiferal Research, Special Publication No. 16.A Guide to Modern Radiolaria

This resource was created by the University of Wales, Newport and released as an open educational resource through the 'C-change in GEES' project exploring the open licensing of climate change and sustainability resources in the Geography, Earth and Environmental Sciences. The C-change in GEES project was funded by HEFCE as part of the JISC/HE Academy UKOER programme and coordinated by the GEES Subject Centre. This resource is licensed under the terms of the Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales license ( However the resource, where specified below, contains other 3 rd party materials under their own licenses. The licenses and attributions are outlined below: 1.The name of the University of Wales, Newport and its logos are unregistered trade marks of the University. The University reserves all rights to these items beyond their inclusion in these CC resources. 2.The JISC logo, the C-change logo and the logo of the Higher Education Academy Subject Centre for the Geography, Earth and Environmental Sciences are licensed under the terms of the Creative Commons Attribution -non-commercial-No Derivative Works 2.0 UK England & Wales license. All reproductions must comply with the terms of that license. AuthorProfessor Simon K. Haslett Research AssistantJonathan Wallen Institute - OwnerUniversity of Wales, Newport TitleRadiolarian Micropalaeontology: Morphology and Taxonomy DescriptionAn introduction to Polycystine Radiolaria Date Created2010 Educational LevelHigher KeywordsUKOER, GEESOER, Microfossil, Radiolaria Creative Commons LicenseAttribution-Non-Commercial-Share Alike 2.0 UK: England & Wales