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Streblotrypa
Classification
Phylum:
Bryozoa
Subphylum:
Ectoprocta
Class:
Gymnolaemata
Order:
Cryptostomata
Suborder:
Rhabdomesina
Family:
Hyphasmoporidae
Formal Genus Name and Reference:
Streblotrypa VINE, 1885, p. 391
Type Species:
S. nicklisi; M; Carb.; Yorkshire, Eng.}
Images
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Synonyms
Lanopora
Geographic Distribution
USSR, S.E.Asia, Japan, Australia, N.Am.
Age Range
Beginning Stage in Treatise Usage:
U.Miss. (Meramec.)
Beginning International Stage:
Visean
Fraction Up In Beginning Stage:
28
Beginning Date:
342.13
Ending Stage in Treatise Usage:
U.Perm.
Ending International Stage:
Changhsingian
Fraction Up In Ending Stage:
100
Ending Date:
251.9
Description
Branch diameters 0.7 to 2.5 mm, usually constant between bifurcations. Weak to well-developed longitudinal ridges separating apertural rows. Metapores usually densely spaced between autozooecia, rarely scattered in exozone; present or absent beyond distolateral margins of zooecial apertures, arising in exozone or rarely in late endozone. Axial region varied; ranging from few axial zooecia to large, well-defined axial bundles. Individual zooecia rarely diverging from well-defined axial bundles, but commonly diverging and developing morphology typical of autozooecia in species with few axial zooecia. Autozooecial bases attenuated to weakly inflated. Autozooecial cross sections polygonal in endozone, irregular or hexagonal. Zooecial divergence from axial region approximately 20°to 30°. Zooecial bend generally abrupt. Living chamber flattened proximally in exozone, chamber oriented about 90°to branch surface. Autozooeciallength usually 8 to 12 times diameter. Longitudinal arrangement of autozooecia usually regular. True hemisepta rare or lacking; single, straight, slender hemiseptum may be present on distal wall in late endozone; proximal wall at zooecial bend inflated. Scattered diaphragms may be present. Exozonal width usually between one-third and half branch radius, rarely greater. Zooecial boundary usually well defined, irregular, rarely not visible; discontinuous, nonlaminated wall material may be present. Lamellar profile rounded in exozone. Stylets usually absent; paurostyles and weakly developed acanthosyles may be present. [VINE'S ( 1885) one specimen of S. nicklisi from England is lost. DUNCAN (1949) recommended replacement of VINE'S specimen by a suite of fossils in collections of the U.S. National Museum, but such replacement does not fulfill ICZN requirements for designation of a neotype. Nevertheless, the concept ofS. nicklisi has been generally based on the North American specimens illustrated here. Lanopora ROMANCHUK (1975) differs from Streblotrypa only in presence of swellings on longitudinal ridges, a feature I consider to be of no generic significance, and Lanopora is herein synonymized with Streblotrypa. Some species of Streblotrypa and Streblascopora BASSLER, 1952, are distinct, but others combine features of both genera; therefore, Streblascopora is herein reduced to subgenus rank under Streblotrypa. Streblotrypa is similar to the nikiforovellid Streblotrypella in zooecial orientation, trend toward stylet loss, and concentration of metapores proximal to zooecial apertures.}
References
Bassler, R. S., ,, , 1929, The Permian Bryozoa of Timor: Paläontologie von Timor, Lief. 16, no. 28, p. 36-89, pl. 225-247 (Stuttgart).
Museum or Author Information
Classification
Phylum:
Bryozoa
Subphylum:
Ectoprocta
Class:
Gymnolaemata
Order:
Cryptostomata
Suborder:
Rhabdomesina
Family:
Hyphasmoporidae
Formal Genus Name and Reference:
Streblotrypa VINE, 1885, p. 391
Type Species:
S. nicklisi; M; Carb.; Yorkshire, Eng.}
Images
(Click to enlarge in a new window)Synonyms
Lanopora
Geographic Distribution
USSR, S.E.Asia, Japan, Australia, N.Am.
Age Range
Beginning Stage in Treatise Usage:
U.Miss. (Meramec.)
Beginning International Stage:
Visean
Fraction Up In Beginning Stage:
28
Beginning Date:
342.13
Ending Stage in Treatise Usage:
U.Perm.
Ending International Stage:
Changhsingian
Fraction Up In Ending Stage:
100
Ending Date:
251.9
Description
Branch diameters 0.7 to 2.5 mm, usually constant between bifurcations. Weak to well-developed longitudinal ridges separating apertural rows. Metapores usually densely spaced between autozooecia, rarely scattered in exozone; present or absent beyond distolateral margins of zooecial apertures, arising in exozone or rarely in late endozone. Axial region varied; ranging from few axial zooecia to large, well-defined axial bundles. Individual zooecia rarely diverging from well-defined axial bundles, but commonly diverging and developing morphology typical of autozooecia in species with few axial zooecia. Autozooecial bases attenuated to weakly inflated. Autozooecial cross sections polygonal in endozone, irregular or hexagonal. Zooecial divergence from axial region approximately 20°to 30°. Zooecial bend generally abrupt. Living chamber flattened proximally in exozone, chamber oriented about 90°to branch surface. Autozooeciallength usually 8 to 12 times diameter. Longitudinal arrangement of autozooecia usually regular. True hemisepta rare or lacking; single, straight, slender hemiseptum may be present on distal wall in late endozone; proximal wall at zooecial bend inflated. Scattered diaphragms may be present. Exozonal width usually between one-third and half branch radius, rarely greater. Zooecial boundary usually well defined, irregular, rarely not visible; discontinuous, nonlaminated wall material may be present. Lamellar profile rounded in exozone. Stylets usually absent; paurostyles and weakly developed acanthosyles may be present. [VINE'S ( 1885) one specimen of S. nicklisi from England is lost. DUNCAN (1949) recommended replacement of VINE'S specimen by a suite of fossils in collections of the U.S. National Museum, but such replacement does not fulfill ICZN requirements for designation of a neotype. Nevertheless, the concept ofS. nicklisi has been generally based on the North American specimens illustrated here. Lanopora ROMANCHUK (1975) differs from Streblotrypa only in presence of swellings on longitudinal ridges, a feature I consider to be of no generic significance, and Lanopora is herein synonymized with Streblotrypa. Some species of Streblotrypa and Streblascopora BASSLER, 1952, are distinct, but others combine features of both genera; therefore, Streblascopora is herein reduced to subgenus rank under Streblotrypa. Streblotrypa is similar to the nikiforovellid Streblotrypella in zooecial orientation, trend toward stylet loss, and concentration of metapores proximal to zooecial apertures.}
References
Bassler, R. S., ,, , 1929, The Permian Bryozoa of Timor: Paläontologie von Timor, Lief. 16, no. 28, p. 36-89, pl. 225-247 (Stuttgart).