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Class Graptolithoidea and Graptolite Taxonomy by N.V. Beklemishev (1951, 1970)

 

Phylum XIII. HEMICHORDA

 

 

 

Class 52. GRAPTOLITHOIDEA n.

 

 

 

Ordo STOLONOIDEA †

Ordo CAMAROIDEA †

Ordo TUBOIDEA †

Ordo DENDROIDEA †

Ordo GRAPTOLOIDEA †

Ordo RHABDOPLEUROIDEA n.

Ordo CEPHALODISCOIDEA n.

 

 

 

 

 

 

 

 

The system proposed in:

Beklemishev, V.N. 1951. Toward the building of system of animals. Deuterostomia, their origin and composition. [in Russian]. - Uspekhi Sovremennoy Biologii 32, 256-270.

See also:

Beklemishev, V.N. (1970). Principles of Comparative Anatomy of Invertebrates, v. 1 490 pp., vol 2., 529 pp. Oliver and Boyd, Edinburgh.

 

Mierzejewski & Kulicki (2001, p. 169) wrote:

"Beklemishev (1951, 1970) [...] proposed the class Graptolithoidea to embrace two diverse taxa: the extinct class Graptolithina (with orders Stolonoidea, Camaroidea, Tuboidea, Dendroidea, and Graptoloidea), and the extant class Pterobranchia (with the orders Rhabdopleuroidea and Cepahlodiscoidea). The most important common feature of the Graptolithoidea (with the exception of the enigmatic living Atubaria Sato, 1936) is the presence of an organic sclerotized exoskeleton composed of growth bands called fusellar increments or simply fuselli. As stated by Kozłowski (1947, 1949, 1966), fusellar tissue is not known in any other fossil or living animal (for summary of ultrastructural and biochemical study of this tissue see Armstrong et al. 1986; Urbanek 1986; Mierzejewski & Kulicki 2001). The presence of such a peculiar structural element makes the Graptolithoidea a very coherent group. It is remarkable that morphological differences between some living and fossil sessile Graptolithoidea are less pronounced than the differences between the sessile and the planktic orders within this class (Urbanek 1986). Beklemishev (1951, 1970), as pointed out by Urbanek (1986), erected the class Graptolithoidea, anticipating the results of future submicroscopic and molecular investgations and eliminated the actualistic bias in the recognition of the Graptolithina and the Pterobranchia as taxa of the same rank. Recent morphological and ultrastructural investigations by Urbanek & Dilly (2000) and Mierzejewski & Kulicki (2001) on the stolon system and periderm of the fossil and living Rhabdopleuroidea seem to support decisively Beklemishev's (1951, 1970) concept of the class Graptolithoidea. Similarly as Beklemishev (1951, 1970), we retain the names Pterobranchia and pterobranchs as common, non-taxonomic names given to cephalodiscids and rhabdopleurids, i.e., extant orders of the Graptolithoidea."