Orthothecida

Belongs within: Hyolitha.

The Orthothecida are a group of hyoliths defined by Kruse (2002) as including those species in which the dorsum and venter were clearly differentiated, but without a ligula along the venter. Families of Orthothecida are primarily distinguished by the shape of the cross-section. Orthothecidae have the transverse section triangular or subtriangular with a planar venter (Kruse 2002).

<==Orthothecida
    |  i. s.: ‘Hyolithes’ glabra Walcott 1911M90
    |--GracilithecaL95 [GracilithecidaeK02]
    |    |--G. bayonet (Matthew 1899)L95
    |    `--G. ternata Sysoiev 1968W93
    |--Ceratotheca Novak 1891F62 [CeratothecidaeW93]
    |    |--*C. adunca (Barrande 1867) [=Hyolithes aduncus]F62
    |    `--C. abundica (Barrande 1867)W93
    |--Tetratheca [Tetrathecidae]W93
    |    |--‘Quadrotheca’ clinisepta Syssoiev 1960 [=Costatheca clinisepta]M02
    |    `--T. hexagona Sysoiev 1968W93
    |--Quadrotheca Syssoiev 1958 [Quadrothecidae]M02
    |    |--*Q. quadrangularis (Holm 1893) (see below for synonymy)M02
    |    |--Q. rediviva Marek 1967M02
    |    `--Q. shipaiensis Qian, Cheng & Chen 1979M02
    |--Istithecidae [Lentithecidae, Nikathecidae]K02
    |    |--Istitheca lenae Sysoiev 1968W93
    |    |--Plicitheca sulcata Sysoiev 1968W93
    |    `--Lentitheca Syssoiev 1958F62
    |         `--*L. peracuta (Holm 1893) [=Hyolithes peracutus]F62
    |--Obliquatheca [Obliquathecidae]W93
    |    |--O. acostae Sysoiev 1968W93
    |    |--O. aldanica (Sysoiev 1960)W93
    |    |--O. bicostata (Missarzhevsky 1969)W93
    |    |--O. inermis Sysoiev 1968W93
    |    `--O. pulchella Valkov 1975W93
    |--OrthothecidaeF62
    |    |--Bactrotheca Novák 1891F62
    |    |    `--*B. teres (Barrande 1867) [=Hyolithes teres]F62
    |    |--Cryptocaris Barrande 1872F62
    |    |    `--*C. suavis Barrande 1872F62
    |    |--Semielliptotheca Syssoiev 1958F62
    |    |    `--*S. rosmara (Holm 1893) (see below for synonymy)M02
    |    `--Orthotheca Novak 1886M90
    |         |--*O. intermedia Novak 1886F62 [=Hyolithes (Orthotheca) intermediusMB-M99]
    |         |--O. bayonet Metthew 1899M90
    |         |--O. corneola (Holm 1893) (see below for synonymy)MB-M99
    |         |--O. groedbyensis Poulsen 1967MB-M99
    |         |--O. johnstrupi (Holm 1893) [=Hyolithes (Orthotheca) johnstrupi]MB-M99
    |         |--O. pervilis Poulsen 1967MB-M99
    |         |--O. pugio Matthew 1899M90
    |         |--O. sica Matthew 1899M90
    |         `--O. stiletto Matthew 1899M90
    |--Allathecidae [Aldanothecidae, Chelsonellidae, Curtithecidae, Exilithecidae, Fistulosithecidae, Tchuranithecidae]K02
    |    |--Mooritheca Val’kov 1975K02
    |    |--Egdethica aldanica Missarzhevsky 1969W93
    |    |--Majatheca Missarzhevsky 1969W93, D78
    |    |    `--M. tumefacta Missarzhevsky 1969W93
    |    |--Micatheca stupenda Sysoiev 1968W93
    |    |--Ovalitheca rasa Sysoiev 1968W93
    |    |--Chelsonella vanuxemi (Walcott 1884)MB-M99
    |    |--TchuranithecaW93
    |    |    |--T. simplicis Sysoiev 1968W93
    |    |    `--T. sinuata Sysoiev 1968W93
    |    |--UniformithecaW93
    |    |    |--U. jasmiri (Sysoiev 1959)W93
    |    |    `--U. rhombiformis (Sysoiev 1963)W93
    |    |--ExilithecaW93
    |    |    |--E. ancestralis Sysoiev 1968W93
    |    |    |--E. multa Sysoiev 1968W93
    |    |    `--E. oblongata Sysoiev 1968W93
    |    |--Allatheca Missarzhevsky 1969MB-M99
    |    |    |--A. canaKB09
    |    |    |--A. concinna Missarzhevsky 1969W93
    |    |    `--A. corrugata Missarzhevsky 1969W93
    |    `--LenathecaW93
    |         |--L. dolosa Sysoiev 1972W93
    |         |--L. groenlandica (Poulson 1932)W93
    |         |--L. pyramidata (Sysoiev 1968)W93
    |         `--L. triconcava (Sysoiev 1968)W93
    `--NovitatidaeM02
         |--Panitheca Marek 1967K02
         |--Tcharatheca Syssoiev 1972M02
         |--Eonovitatus Syssoiev 1968M02
         |--Devoniotheca Malinky 1987M02
         |--Contitheca Syssoiev 1972M02
         |    `--C. corMW04
         |--Nephrotheca Marek 1966K02
         |    `--N. housina Marek 1967MB-M99
         |--Decoritheca Syssoiev 1972 [Decorithecidae]M02
         |    |--D. affinis (Holm 1893) [=Hyolithus (Orthotheca) affinis, Hyolithes affinis]MB-M99
         |    `--D. lineatulaM02
         |--Foersteotheca Malinky 1987M02
         |    |--*F. newsomensis (Foerste 1903) [=Hyolithes newsomensis]K02
         |    `--F. dubecensis (Marek 1967) [=Nephrotheca dubecensis]K02
         |--Novitatus Syssoiev 1968M02
         |    |--N. incompletus (Meshkova 1974)W93
         |    |--N. lermontovae Sysoiev 1968W93
         |    |--N. oblongus (Meshkova 1974)W93
         |    `--N. tarynicus Sysoiev 1968W93
         |--Holmitheca Syssoiev 1968M02
         |    |--*H. obvia Syssoiev 1968K02
         |    |--‘Hyolithes’ quadricostatus Shaler & Foerste 1888M02
         |    |--H. ulterior (Sysoiev 1968)W93
         |    `--H. zhuravlevae Sysoiev 1972W93
         `--Trapezotheca Syssoiev 1958M02
              |--*T. aemula (Holm 1893) [=Hyolithus (Orthotheca) aemulus]M02
              |--T. aldanica Syssoiev 1960M02
              |--T. bicostata Missarzhevsky 1969W93
              |--T. dens (Holm 1893) [=Hyolithus (Orthotheca) dens, Bactrotheca dens, Semielliptotheca dens]M02
              |--‘Hyolithes’ hexagonus Barrande 1867M02
              |--T. novaki Syssoiev 1960 [=Hyolithes quadricostatus Novák 1891 non Shaler & Foerste 1888]M02
              `--T. pistrinis Poulsen 1967MB-M99

Orthotheca corneola (Holm 1893) [=Hyolithus (Orthotheca) corneolus, Circotheca corneola, Hexitheca corneolus, Hyolithes (Orthotheca) corneolus; incl. Hyolithus (O.) corneolus mut. avus Holm 1893, Circotheca ava, Hyolithes (O.) avus, Hyolithus (O.) atavus]^MB-M99

*Quadrotheca quadrangularis (Holm 1893) [=Hyolithes (Orthotheca) quadrangularis, Bactrotheca quadrangularis, Hyolithus (l. c.) (O.) quadrangularis]^M02

*Semielliptotheca rosmara (Holm 1893) [=Hyolithes (Orthotheca) rosmarus, Bactrotheca rosmarus, Hyolithus (l. c.) rosmarus, Semielliptotheca (Hyolithes) rosmarus (l. c.)]^M02

*Type species of generic name indicated

References

[D78] Durham, J. W. 1978. The probable metazoan biota of the Precambrian as indicated by the subsequent record. Ann. Rev. Earth Planet Sci. 6: 21–42.

[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.

[L95] Landing, E. 1995. Upper Placentian–Branchian series of mainland Nova Scotia (middle–upper Lower Cambrian): faunas, paleoenvironments, and stratigraphic revision. Journal of Paleontology 69 (3): 475–495.

[M90] Malinky, J. M. 1990. Cambrian Hyolitha from northeast Canada: reappraisal of the hyolith orders Camerothecida and Diplothecida. Journal of Paleontology 64 (4): 587–595.

[M02] Malinky, J. M. 2002. A revision of Early to Mid Ordovician hyoliths from Sweden. Palaeontology 45: 511–555.

[MB-M99] Malinky, J. M., & V. Berg-Madsen. 1999. A revision of Holm’s Early and early Mid Cambrian hyoliths of Sweden. Palaeontology 42: 25–65.

[MW04] Malinky, J. M., M. A. Wilson, L. E. Holmer & H. Lardeux. 2004. Tube-shaped incertae sedis. In: Webby, B. D., F. Paris, M. L. Droser & I. G. Percival (eds) The Great Ordovician Biodiversification Event pp. 214–222. Columbia University Press.

[W93] Wills, M. A. 1993. ?Mollusca incertae sedis. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 265–270. Chapman & Hall: London.