Specimens of Amplexograptus, probably A. perexcavatus, photographed by Mark Wilson.

Belongs within: Bireclinata.

The Diplograptidae are a group of graptoloids known from the Lower Ordovician to the Lower Silurian. Members of this family have a biserial rhabdosome with a symmetrical proximal end (Fortey & Cooper 1986), with the second theca having a right-handed origin from the first theca. They include the distinctive Lower Ordovician genus Dicaulograptus, which possesses a minute rhabdosome with introverted apertures adjacent to long slender spines at the base of the pleural lists (Bulman 1970).

    |--Dicaulograptus Rickards & Bulman 1965 FC86, B70 [Dicaulograptidae]
    |    `--*D. hystrix (Bulman 1932) [=Lasiograptus hystrix] B70
    |--Cystograptus Hundt 1942 B70
    |    |--*C. vesiculosus (Nicholson 1869) [=Diplograpsus vesiculosus; incl. C. speciosus Hundt 1942] B70
    |    `--C. penna B70
    |--Cephalograptus Hopkinson 1869 [=Cephalograpsus] B70
    |    |--*C. cometa (Geinitz 1852) [=Diplograpsus cometa] B70
    |    |--C. acuminatus [=Akidograptus acuminatus] B70
    |    `--C. tubulariformis B70
    |--Petalograptus Suess 1851 [=Diprion Barrande 1850, Petalolithus Suess 1851] B70
    |    |--*P. folium (Hisinger 1837) [=Prionotus folium] B70
    |    |--P. altissimus M79
    |    |--P. insectiformis [=Orthograptus insectiformis] B90
    |    |--P. obuti [=Orthograptus obuti] B90
    |    `--P. speciosus B70
    |--Pseudoclimacograptus Přibyl 1947 B70
    |    |--*P. (Pseudoclimacograptus) scharenbergi (Lapworth 1876) [=Climacograptus scharenbergi] B70
    |    |--P. (Clinoclimacograptus Bulman & Rickards 1968) B70
    |    |    `--P. (*C.) retroversus Bulman & Rickards 1968 B70
    |    `--P. (Metaclimacograptus Bulman & Rickards 1968) B70
    |         `--P. (*M.) hughesi (Nicholson 1869) [=Diplograpsus hughesi] B70
    |--Amplexograptus Elles & Wood 1907 (see below for synonymy) B70
    |    |--*A. perexcavatus (Lapworth 1876) [=Diplograptus perexcavatus] B70
    |    |--A. arctus F71
    |    |--*Comograptus’ comatus Obut & Sobolevskaya in Obut, Sobolevskaya & Merkureva 1968 B70
    |    |--A. confertus B70
    |    |--*Hedrograptus’ janischewskyi Obut 1949 B70
    |    `--A. maxwelli FC86
    `--Diplograptus M’Coy 1850 [=Diplograpsis; incl. Mesograptus Elles & Wood 1907] B70
         |--*D. pristis (Hisinger 1837) B70 [=Prionotus pristis W77, Graptolithus (Diplograptus) pristis W77]
         |--D. carnei Hall 1902 F71
         |--D. decoratus B70
         |--D. foliaceus (Murchison 1839) [=Graptolithus foliaceus, *Mesograptus foliaceus] B70
         |--D. hypniformis (White 1874) [=Graptolithus (Diplograptus) hypniformis] W77
         |--‘Mesograptus’ ingens F71
         |--D. magnus [=Mesograptus magnus] RG04
         |--D. manduramae Hall 1900 F71
         |--D. maxwelli B70
         `--D. multidens B70

Amplexograptus Elles & Wood 1907 [incl. Comograptus Obut & Sobolevskaya in Obut, Sobolevskaya & Merkureva 1968, Hedrograptus Obut 1949] B70

*Type species of generic name indicated


[B90] Bates, D. E. B. 1990. Retiolite nomenclature and relationships. Journal of the Geological Society 147: 717–723.

[B70] Bulman, O. M. B. 1970. Graptolithina with sections on Enteropneusta and Pterobranchia. In: Teichert, C. (ed.) Treatise on Invertebrate Paleontology pt V 2nd ed. pp. V1–V149. The Geological Society of America, Inc.: Boulder (Colorado), and the University of Kansas: Lawrence (Kansas).

[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1–167.

[FC86] Fortey, R. A., & R. A. Cooper. 1986. A phylogenetic classification of the graptoloids. Palaeontology 29: 631–654.

[M79] Müller, A. H. 1979. Fossilization (taphonomy). In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A2–A78. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[RG04] Racheboeuf, P. R., R. Gourvennec, M. Deynoux & D. Brice. 2004. The Devonian of the Hodh area (Islamic Republic of Mauritania): paleontology and stratigraphy. Journal of Paleontology 78 (1): 98–110.

[W77] White, C. A. 1877. Report upon the invertebrate fossils collected in portions of Nevada, Utah, Colorado, New Mexico, and Arizona, by parties of the expeditions of 1871, 1872, 1873, and 1874. U.S. Geographical Surveys West of the One Hundredth Meridian 4 (1): 1–219, pls 1–21.

No comments:

Post a Comment

Markup Key:
- <b>bold</b> = bold
- <i>italic</i> = italic
- <a href="http://www.fieldofscience.com/">FoS</a> = FoS