Circothecida

Schematic drawings of Loculitheca kunka, from Kruse (2002).

Belongs within: Hyolitha.

The Circothecida are a group of hyoliths in which the dorsum and venter are undifferentiated or weakly differentiated (Kruse 2002).

<==Circothecida
    |--Paragloborilidae K02
    |--Spinulitheca KB09 [Extentithecidae, Spinulithecidae K02]
    |    `--S. billingsi KB09
    |--Circothecidae K02
    |    |--Guduguwan Kruse 1990 K02
    |    |    `--*G. hardmani (Etheridge in Foord 1890) [=Salterella hardmani, Biconulites hardmani] K02
    |    |--Larawa [Larawidae] K02
    |    |    `--L. djanin Kruse 1990 K02
    |    `--Circotheca Syssoiev 1958 F62
    |         `--*C. stylus (Holm 1893) [=Hyolithes stylus] F62
    `--Turcuthecidae K02
         |--Loculitheca Sysoyev 1968 K02
         |    |--*L. anulata (Sysoyev 1959) [=Circotheca anulata] K02
         |    `--L. kunka Kruse 2002 K02
         `--Turcutheca K02
              |--T. bituba K02
              `--T. cylindrica K02

*Type species of generic name indicated

REFERENCES

[F62] Fisher, D. W. 1962. Small conoidal shells of uncertain affinities. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt W. Miscellanea: Conodonts, Conoidal Shells of Uncertain Affinities, Worms, Trace Fossils and Problematica pp. W98–W143. Geological Society of America, and University of Kansas Press.

[KB09] Kouchinsky, A., S. Bengtson, W. Feng, R. Kutygin & A. Val’kov. 2009. The Lower Cambrian fossil anabaritids: affinities, occurrences and systematics. Journal of Systematic Palaeontology 7 (3): 241–298.

[K02] Kruse, P. D. 2002. Biostratigraphic potential of Middle Cambrian hyoliths from the eastern Georgina Basin. Alcheringa 26: 353–398.