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| Haplograptus wisconsinensis Cambrian, Wisconsin, U.S.A. Holotype. |
| From Ruedemann. |
| Haplograptus wisconsinensis, the type species of the genus Haplograptus, was described by Rudolf Ruedemann from the Cambrian (Trempealeau formation) of two localities in Wisconsin. Later, it was listed also by Decker (1936) from the middle Arbuckle limestone of Oklahoma. Description by Ruedemann (1947, p. 264): "Rhabdosome consisting of a single sicula or theca or a few thecae produced by irregular budding. Sicula (?) an arched or straight slender cone, about 9-12 mm long and 1-1.5 mm wide at aperture. First theca originates close to aperture of supposed sicula, the others irregularly wide at aperture. They probably do not reach size of sicula for the first theca in the specimen measures but 0.4 mm long when it has already produced two budding thecae in its turn." |
| List of species: Haplograptus canadensis Ruedemann, 1947; Ordovician, Canada. Haplograptus fruticosus Yu Jian-hua, Liu Huai-bao & Fang Yi-ting, 1985 Haplograptus sinicus Mu et al. Haplograptus sinicus minutus Yu Jian-hua, Liu Huai-bao & Fang Yi-ting, 1985; early Ordovician, China. Haplograptus vermiformis Ruedemann, 1947; Upper Cambrian, U.S.A. Haplograptus wisconsinensis Ruedemann, 1933; Cambrian, U.S.A. |
| Diagnosis of Haplograptus by O.M. B. Bulman (1955, 1970): "Elongate conical or vermiform thecae associated to form an irregularly dendroid rhabdosome." |
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| R e f e r e n c e s : Decker, C. E. 1936. Some tentative correlations on the basis of graptolites of Oklahoma and Arkansas. - American Assoc. Petrol. Geol., Bull., 20, 3, 301-311. Ruedemann, R. 1933. Cambrian graptolite faunas of North America. - Milwaukee Pub. Museum, Bulletin, 12, 3, 307-348. Ruedemann, R. 1947. Graptolites of North America. - Geological Society of America, Memoir 19. Sennikov, N.V. 1996. Paleozoic graptolites from the Central Siberia. Published by Siberian Branch SPC UIGGM SB RAS, Novosibirsk, 227pp. |
| The graptolite-like fossil genus Haplograptus was proposed by Ruedemann (1933) in order to embrace two species: Haplograptus wisconsinensis Ruedemann, 1933 (type species of the genus) and H. vermiformis Ruedemann, 1933. These forms were recovered from the Cambrian of U.S.A. Further findings of this genus were obtained from the Cambrian of China and Siberia, and from the Ordovician of Canada. Ruedemann (1947) and some other writers placed Haplograptus among the Dendroidea. Bulman (1955) treated this form as representative of his dendroid family Chaunograptidae. Finally, he placed it among graptolite-like fossils of uncertain taxonomic position (Bulman 1970). |
| Haplograptus Ruedemann, 1933 |
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