The present paper describes a bryozoan fauna from the Devonian of Holy Cross Mountains (Poland) which includes nine species. Six species were described from the Dobruchna Member of the Skały Formation (Eifelian) of Skały section: Cyclotrypa sp., Fistuliphragma gracilis, Leioclema passitabulatum, Intrapora leunisseni, Laxifenestella sp., Hemitrypella nodulosa. The cryptostome species Bigeyella indigena was identified from the Laskowa Góra Beds (upper Givetian) of Józefka Hill at Górno. The fenestrate Rectifenestella sp. is described from the lower Frasnian Kowala Formation (Kadzielnia Member) of Bolechowice and Kielce. The new monotypic fenestrate genus Juanopora elegans gen. et sp. nov. is described from the Wietrznia Beds (upper Givetian) of Wietrznia-I quarry at Kielce. The described bryozoans show palaeobiogeographical connections to the Middle–Upper Devonian of Germany, Spain, and Armenia. The bryozoan faunas of the Holy Cross Mountains are in accordance with the worldwide acme of the sessile filter-feeding benthos during the Givetian age, followed by a two-stage decline in diversity due to the Taghanic and Frasnian crises.

The Halevikdere Formation of southern Turkiye yields an under-explored archive of Late Ordovician marine ecosystems. Our knowledge about Ordovician bryozoans in Turkiye is restricted due to the poor preservation of material. The first report of the Hirnantian high-latitude north Gondwanan bryozoans from southeastern Turkiye (Mardin-Derik area, Halevikdere Formation) is presented here. The Late Ordovician (Sandbian-Hirnantian) predominantly fine-grained succession of Derik is among the most remarkable Early Palaeozoic successions in southeastern Turkiye, but its precise geological age is poorly constrained. New bryozoan-rich sequence of glacio-marine related deposits contains indeterminate crinoids and brachiopods. Here we describe a new fauna of bryozoans from the ice-distal glaciomarine succession of the Halevikdere Formation, corresponding to the northern margin of the Arabian Plate. Three palaeostomate bryozoan species were identified: the esthonioporate Esthonioporata sp. indet., cryptostomes Graptodictya sp., and Ptilodictyina sp. indet. (aff. Proavella proava). In this study, anew trace fossil assemblage comprising several ichnotaxa is also documented from the upper part of the bryozoan-bearing sequence of the Hirnantian Halevikdere Formation. The identified bryozoans are related to the typical Ordovician taxa, but their presence in the assemblage, previously reported only from the Upper Ordovician of the Baltic region, is noticeable. These bryozoans and ichnofossils are typically associated with shallow marine environments, reflecting the conditions that prevailed during the time of their formation. (c) 2025 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

The major animal body plans originated during the Cambrian explosion, yet the phylum Bryozoa has remained a conspicuous exception to this pattern1. The initial discovery of Protomelission gatehousei2 provided compelling evidence for a Cambrian origin for the Bryozoa, together with other major metazoan phyla and compatible with independent molecular clock estimates3-7. Nevertheless, the scarcity of definitive soft-tissue anatomy and diagnostic skeletal microstructure has left its phylogenetic affinities ambiguous and debated8,9. Here we report exquisite fossils of P. gatehousei and a new taxon, Dayingomelission hexaclitia gen. et sp. nov., from the early Cambrian Xiannüdong Formation of China. These specimens preserve in situ phosphatized soft tissues in modular skeletons, revealing critical anatomical structures, including styles, annular muscles, membranous sacs and ring septa. This suite of traits provides definitive evidence that these taxa belong to the Bryozoa. Phylogenetic analysis incorporating these new features identifies them as crown group stenolaemates. These results confirm a Cambrian origin for the phylum and reveal an unexpected early disparity in colonial architecture, demonstrating that bryozoan diversification was an integral component of the Cambrian radiation. Moreover, the early appearance of a differentiated stenolaemate crown group indicates a still deeper origin for the bryozoan stem lineage than was first apparent.

The bryozoan fauna from the Samnuuruul Formation (Upper Devonian, Famennian) in southwestern Mongolia contains sixteen species of which nine are described in detail from the Hushoot Shiveetiin gol section. The studied fauna comprises two cystoporates, two trepostomes, two cryptostomes, and three fenestrates. One fenestrate species is new: Hemitrypa lui n. sp. The majority of species show palaeobiogeographic connections to the Middle Devonian to Upper Devonian successions from China, Russia and Kazakhstan. The studied fauna is numerically dominated by the cystoporates Cyclotrypa subtilis (Nekhoroshev, 1977) and Sulcoretepora hextolgayensis Xia, 1997, whereas other species are relatively rare. The bryozoans develop exclusively arborescent growth forms implying a low energy setting of the outer shelf.

Six new symbiotic associations between erect branching bryozoan colonies and tentaculitoid tubewormlike organisms have been described from argillaceous carbonate rocks of the Ludfordian of Saaremaa Island, Estonia. Several symbiotic associations occur in the Kuressaare Formation: Conchicolites sp.- Fistulipora sp. A and Fistulipora sp. B, Palaeoconchus sp. - Fistulipora sp. A, Conchicolites sp. - ?Eridotrypella sp., Conchicolites sp.- ?Anisotrypa proavus, Conchicolites sp. -?Leptotrypella versimilis and Monotrypa sp. - unknown endozoobiont association. The colonization of bryozoans by cornulitids and microconchids likely occurred because the former provided a suitable hard substrate on an otherwise soft clay sea floor. Most cornulitids had endobiotic life modes and were completely intergrown with their host bryozoans. There is no evidence of how cornulitids might have provided some advantage to the bryozoan host. However, given the likelihood of feeding competition, these associations are more appropriately qualified as mildly parasitic. (c) 2025 Elsevier Masson SAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Symbiotic (mutualistic) relationships are hypothesized for species of the tabulate coral genus Cladochonus McCoy, 1847 associated with trepostome and cryptostome bryozoans in the Devonian. The species Cladochonus isaacmariai n. sp. from the Birdsong Shale (Lower Devonian, middle Lochkovian) of Tennessee, USA, was an obligatory symbiont of the trepostome bryozoan Nakremella symbiotica n. gen. n. sp. Cladochonus sp. A and Cladochonus sp. B from the Givetian (Middle Devonian) of Sauerland, Germany, are intergrown with the cryptostome species Intrapora variabilis Ernst, 2008. This interrelation is interpreted to be obligatory for the coral and facultative for the bryozoan. The coral symbionts benefitted from the bryozoans due to the enhanced mechanical stabilisation and enhanced feeding, while the bryozoans benefitted from the provision of a substrate, access to the higher tiering (arborescent growth), and receiving protection from the corals.

Specimens of the rugose coral Streptelasma? sp. are found intergrown with a host bryozoan Oanduellina bella in the lower Katian of Estonia. Rugosa also occur in the bryozoan Proavella proava. This is the earliest and only known record of endobiotic rugose symbionts in cryptostome bryozoans from the Late Ordovician of Baltica. The erect bryozoan colonies provided symbiotic Rugosa with both a higher and more advantageous tier for feeding in the water column and a hard substrate that these encrusting Rugosa required. The rugose corals may have protected the bryozoans with their stinging cells against predators. The lack of malformations in the bryozoan zooid architecture and their normal dimensions around the Rugosa show that the relationship between the Rugosa and bryozoans could have been mutualistic, which is similar to many other Rugosa-bryozoan associations in the Late Ordovician of Baltica, although the exact nature of this association remains uncertain.

Bryozoans represent a dominant faunal element in the Lower Permian of Western Australia. Here, three new trepostome species are described from the Callytharra Formation (Sakmarian – Artinskian): Nikiforopora haigi sp. nov., Iraidina dendroidea sp. nov., and I. multicava sp. nov. The genera Nikiforopora and Iraidina were previously unknown from the Permian deposits of Australia. The genera have no contemporary equivalents from other areas, so their use for stratigraphic correlation and palaeobiogeography remains limited. Intensive studies of the Permian Bryozoa from Australia appear necessary to better understand the Gondwanan distributions of the genera and species.

The encrusted bivalve steinkerns in the Upper Ordovician of Estonia suggest that the rapid sea-floor cementation facilitated the early lithification of the sediment within the bivalve shell and the shell valves, likely aragonitic in composition, were dissolved due to calcite sea conditions similarly to many other regions in the Ordovician. The abandoned bivalve shells contained cryptic invertebrates. The coelobite fauna was dominated by encrusting brachiopods, followed by bryozoans and cornulitids. The bryozoans and cornulitids do not prefer specific regions of the shell interior, indicating that the waters within the shell were sufficiently nutrient-rich throughout. Encrusting brachiopods are always confined to valve margins, suggesting that the waters were nutrient-rich enough for the brachiopods only at the edge of the outer environment. Thus, it is possible that bryozoans and cornulitids were better adapted for a cryptic life than the encrusting brachiopods in the Late Ordovician of Estonia.

Lower Devonian (Pragian-Emsian) reefal deposits of Sierra Morena (SW Spain) contain locally abundant calcified cyanobacteria, calcareous algae, and various microfossils including foraminifers. Calcified cyanobacteria are represented by Girvanella spp. A–C, which form crusts and clumps of various shapes. Supposed green algae (?Dasycladales) are represented by a new genus with one new species, Bediaella hispanica gen. et sp. nov. Algospongia include Vasicekia margaritula (Saltovskaya, 1986) n. comb. Microproblematica are represented by Rothpletzella sp. The studied assemblages indicate photic and warm conditions in a shallow and well-agitated environment with normal salinity, and probably mirror episodes of shallowing due to eustatic sea level fluctuations.

This paper presents the first contribution to the study of bryozoans from the Frasnian–lower Famennian successions of Armenia. The latter were examined in two distinct localities (Ertych and Noravank) of Central Armenia; abundant fragments of branched ramose and encrusting bryozoans were observed in them, belonging to the orders Trepostomata and Cryptostomata. Their taxonomic assessment led us to recognize four species: two cryptostomes – Euthyrhombopora tenuis Ernst et al., 2017 and Bigeyella indigena (Morozova and Weiss in Morozova et al., 2002) from the Noravank section (Frasnian) – and two trepostomes – Eostenopora sp. and Eridotrypella sp. from the Ertych section (lower Famennian). No cystoporate and fenestrate bryozoans were observed. The identified bryozoans are characteristic of shallow marine or middle shelf paleoenvironments. The presence of Euthyrhombopora tenuis and Bigeyella indigena suggests palaeobiogeographic affinities to contemporary faunas from Iran and Poland, respectively. In addition to our results, an overview of previously published data reveals that the upper Famennian assemblages of bryozoans from the Lesser Caucasus contain more endemic species than those known from the Frasnian and the lowermost Famennian.

The ichnogenus Anoigmaichnus is redefined as a cecidogenus. A new bioclaustration Anoigmaichnus soervensis V iNN & E RNsT csp. nov. has been identified within the cystoporate bryozoan Fistulipora przhidolensis from the upper Pridoli of Saarema Island, Estonia. The bioclaustration associated with this species features cavities with a smooth sheath made of host bryozoan's skeletal material. Directly below the bioclaustration there is a Trypanites boring. The apertures of this bioclaustration shaft rise above the host's growth surface, forming a well-developed apertural rim. Ordovician trepostomes typically exhibited up to four Anoigmaichnus bioclaustrations per colony, whereas Silurian cystoporates showed a prevalence up to ten times higher. It is conceivable that host bryozoan exhibited greater tolerance towards A. soervensis csp. nov. compared to other species of Anoigmnaichnus due to its potentially lower virulence. The polychaetes could potentially have been responsible for creating Anoigmaichnus bioclaustrations in Fistulipora .

Tabulate corals of the genus Favosites Lamarck, 1816 from the Middle Devonian of Mad & egrave;ne el Mrakib (eastern Anti-Atlas, Morocco) were qualitatively and quantitatively studied with respect to their encrusting and boring organisms (skeletobionts). The assemblage, comprising 18 taxa, is numerically dominated by bryozoans, microconchid tubeworms, and auloporid tabulates. Although less diverse, the recognised Favosites-hosted skeletobiont fauna contains taxa described previously from co-occurring brachiopods. As evidenced by the lower mean abundance and density of the skeletobionts, in contrast to the brachiopod hosts, the favositid corals were, however, not preferred substrates for colonisation. Although the skeletobionts occur on both the upper and lower sides of the host colonies, the majority of colonisers thrived on the latter. Such a colonisation pattern may indicate that the favositids were colonised first on the surfaces devoid of the hosts' soft tissue. The upper sides, in turn, were largely covered by polyps, so these areas might have been either colonised post mortem, or the larvae settled on those parts of the living hosts that were devoid of soft tissue. The lack of any skeletobiont group present exclusively on the lower sides indicates that none of the abundant taxa were obligate cryptobionts. The favositids lack any traces after parasitic endobionts, such as, e.g., Chaetosalpinx Sokolov, 1948 and allied cecidotaxa, which may either point to the general absence of such endobionts in the habitat, limited survival of their larvae, or an efficient immune system of the hosts, preventing their settlement.

Four species of Conchicolites and two species of Cornulites occur in the Hirnantian of Estonia. Two new cornulitids Conchicolites corbalengus sp. nov. and Cornulites levigatus sp. nov. have been described from the Siuge Member. This Hirnantian cornulitid tubeworm association is dominated by species of Conchicolites. Most likely, the studied tubeworms represent true dwarf forms among the cornulitids. It is possible that local waters above the organic rich mud on the seafloor were especially rich in nutrients and allowed cornulitid tubeworms to flourish. The Hirnantian fauna of small cornulitids resembles very much that of late Katian of Estonia and shows no decline in the diversity. It appears that the Late Ordovician mass extinction did not immediately affect small cornulitids, if it did at all.

Bryozoan material from the Ferques Formation (Upper Devonian, Frasnian), Boulonnais, France contains two cystoporates Cystiramus cf. kondomensis Morozova, 1959 and Canutrypa francqana Bassler, 1952, a new trepostome species Dyoidophragma bigeyae n. sp., as well as two fenestrates Hemitrypa sp. and Anastomopora inflata (Bigey, 1988b). The diagnosis of the genus Dyoidophragma Duncan, 1939 is revised. The species composition reveals palaeobiogeographic relations to the Middle and Upper Devonian of Belgium, Germany and Poland, as well as possible relation to the Upper Devonian of Kuznetsk Basin in Russia.

Study of extensive bryozoan material from the Middle Devonian (Eifelian-Givetian) of the Eifel (western Rhenish Massif) revealed the presence of four hemitrypid bryozoans (Fenestrata), which are characterised by a peculiar protective superstructure produced by fusion of lateral extensions of keel nodes. Three species are new: Hemitrypa vanessae sp. n., H. sinuosa sp. n., and Hemitrypella nodulosa sp. n. Besides the Eifel occurrences, the species Hemitrypella tubulosa Nekhoroshev, 1948 is known from the Middle Devonian (Eifelian-Givetian) of Mongolia and Russia (Altai), as well as the Lower Devonian (Emsian) of the Cantabrian Mountains, Spain. However, compilation of published records of hemitrypid bryozoans in the Middle Devonian of Europe shows our patchy knowledge about the distribution of this group. The status of the Family Hemitrypidae is discussed. Re-evaluation of the genera Hemitrypa , Hemitrypella , and Neohemitrypa resulted in conclusion that the latter genus is synonymous with Hemitrypella . Kurzfassung: Untersuchung von umfangreichem Bryozoenmaterial aus dem Mitteldevon (Eifelium-Givetium) der Eifel (westliches Rheinisches Schiefergebirge) zeigte die Pr & auml;senz von vier hemitrypiden Bryozoen (Fenestrata), welche sich durch besondere Schutzstrukturen auszeichnen, die durch Verschmelzen von lateralen Erweiterungen der Knoten am Kiel entstanden sind. Drei Arten sind neu: Hemitrypa vanessae sp. n., H. sinuosa sp. n. und Hemitrypella nodulosa sp. n. Au ss erhalb der Eifel ist die Art Hemitrypella tubulosa Nekhoroshev, 1948, aus dem Mitteldevon (Eifelium-Givetium) von Mongolei und Russland (Altai) sowie aus dem Unterdevon (Emsium) von Kantabrischem Gebirge, Spanien, bekannt. Allerdings zeigt die Auswertung der ver & ouml;ffentlichten Daten & uuml;ber die hemitrypiden Bryozoen unser l & uuml;ckenhaftes Wissen & uuml;ber die Verbreitung dieser Gruppe. Der Status der Familie Hemitrypidae wird diskutiert. Neubewertung der Gattungen Hemitrypa , Hemitrypella und Neohemitrypa f & uuml;hrte zu der Schlussfolgerung, dass die letztere Gattung ein Synonym von Hemitrypella ist.

There was a sudden increase in the diversity of bioclaustrations in the Sandbian (Late Ordovician) that continued somewhat more slowly in the Katian. The Sandbian was also the time when bioclaustrations became common, at least in Baltica. The major increase in the diversity of bioclaustrations in the Late Ordovician was an outcome of the GOBE, and we term it the Ordovician Bioclaustration Revolution. The Ordovician Bioerosion Revolution may partially be responsible for beginning of the Ordovician Bioclaustration Revolution in the Sandbian, as a number of these early bioclaustrations started their growth from initial borings. The diversification of bioclaustrations in the Sandbian involves mostly bryozoans and, to a lesser extent, brachiopods as hosts. The Katian increase in bioclaustration diversity involves mostly corals as the hosts and was likely unrelated or at least less influenced by the Ordovician Bioerosion Revolution. A new broadly conical bioclaustration, Kuckerichnus kirsimaei nov. cgen., nov. csp., is here described from the growth surfaces of hemispherical trepostome bryozoan colonies of Diplotrypa bicornis, Mesotrypa orientalis and Mesotrypa excentrica from the early Sandbian (Late Ordovician) of Estonia.

A new bryozoan genus with one new species is described from the Kukruse Stage (Sand-bian, Ordovician) of Estonia: Toomipora kohtlaensis gen. nov., sp. nov. The new genus is placed in the Family Monticuliporidae (Trepostomata) and is characterized by the presence of biconvex cys-tiphragms and hemisepta-like projections in exozones. Function of these structures were apparently re-shaping and reducing of autozooecial living chamber space as well as strengthening of autozooe-cial wall. The described bryozoan developed encrusting and branched colonies with thin exozones.

Trepostome bryozoans, with their thick calcitic skeletons, formed the largest number of symbiotic associations with endobionts in the Phanerozoic. Such associations were also formed by cystoporates, fenestrates, cyclostomes and cheilostomes. Bryozoans formed most of their symbiotic associations with endobiotic cnidarians, and markedly fewer with endobiotic worms and endobiotic lophophorates. The majority of Ordovician endobionts colonized borings in living bryozoans, or bored themselves into living hosts, during the Ordovician Bioerosion Revolution, which created new niches for the evolution of symbiotic relationships. The bryozoans likely became more selective and less symbiont tolerant over the time. Assumed mutualistic endobionts were more common than likely parasites in Phanerozoic bryozoans. The decrease in diversity of parasitic associations and the increase in the number of mutualistic associations from the Ordovician to Devonian can be explained by the evolution of possible bryozoan defense mechanisms likely in the form of chemical secretions. Paleozoic endobiont faunas were more diverse than their Mesozoic and Cenozoic counterparts because of endobiont-friendly Paleozoic trepostomes, and because of the peak in diversity of bryozoans with massive colonies in the early and middle Paleozoic.

Thin sections of three Palaeozoic bryozoans reveal fossilized soft tissues that show the position of organic cuticle and internal structures such as the membranous sac and gut. The fossilization occurred apparently due to fast burial under anoxic conditions. The position of a membranous sac in the Permian trepostome Rhombotrypella superangustata is indicative of a progressive polypide cycle. The position of the polypide in the Ordovician Graptodictya delicata behind the superior and interior hemisepta suggests a protective function of the hemisepta.