Trepostomata

Abstract: The most widely recognized classification of the class Stenolaemata requires that all post-Triassic members belong to the order Cyclostomata and that all were derived from simple Permo-Triassic stomatoporid cyclostomes. This results from pre-Triassic and post-Triassic classifications, independently developed, using different characters and juxtaposed at the Triassic-Jurassic boundary with no consideration of possible phylogenetic connections. Preliminary evidence based on using the same taxonomic characteristics suggests that post-Triassic stenolaemates were also derived from the Paleozoic orders Trepostomata, Cystoporata, and possibly the Cryptostomata, making the present concept of the order Cyclostomata polyphyletic.--Modified journal abstract.

Abstract: The Stenolaemata comprise both basically single-walled forms (Cyclostomata) and doublewalled forms (Trepostomata, Cystoporata and Cryptostomata) from their first appearance in the geological record. At the end of the Palaeozoic the main groups of apparently double-walled stenolaemates died out, and only the single-walled cyclostomates survived. During the Mesozoic, evolution within the Stenolaemata was apparently repeated by the further development of double-walled forms such as cerioporids, lichenoporids and cancelloids, from single-walled ancestors. These double-walled groups are all remarkable homeomorphs of the major Palaeozoic groups of Bryozoa. A monophyletic origin of the post-Palaeozoic Cyclostomata from Palaeozoic single-walled forms is thus suggested.

Abstract: From the Norian-Rhaetian Nayband Formation in the Hambast Mountains near the town of Wali-Abad, Abadeh area, Central Iran, several new bryozoan species belonging to the stenolaemate orders Cyclostomata, Trepostomata, and Cystoporata are described. The bryozoan fauna holds a transitional position between Paleozoic and post-Paleozoic stenolaemate clades. The fauna indicates a close biogeographic connection to Eurasian (Carpathian, Southern Alpine and Caucasian) bioprovinces. Following species are described as new:Diaphragmopora margaritata n.gen., n.sp.,Diaphragmopora cf.D. margaritata, Dyscritella clausa n.sp., andReptonoditrypa abadehnensis n.sp.

Abstract: The Lower to Middle Devonian Santa Lucia Formation of NW Spain contains a rich and well-preserved bryozoan fauna. An assemblage containing 14 species is described from two localities in Cantabrian Mountains, Abelgas, and Paradilla. One new genus with one new species is described: Isostylusabelgasensis n. sp. n. gen. Another two new species have been found: Microcampylusminor n. sp. and Acanthoclema parvula n. sp. Additionally, the following species were identified: Cyclotrypa communis (Ulrich 1890), Fistuliphragma gracilis Ernst 2008a, Leioclema attenuatum Duncan 1939, Hemitrypa cf. tenella Barrande in Pocta 1894, Fenestella aff. parallela Hall 1881, Anastomopora adnata (Hall 1883), Semicoscinium rhombicum Ulrich 1890, Quadrisemicoscinium discretum (Prantl 1932). Three species are described in open nomenclature: Trepostomata sp. indet.1 and 2, and Semicoscinium sp. The described bryozoan fauna shows connections to the Lower Devonian of Bohemia, and to the Middle Devonian of Rhenish Massif and North America.