Taxonomy, ecology and zoogeography of the Recent species of Rhamphostomella Lorenz, 1886 and Mixtoscutella n. gen. (Bryozoa, Cheilostomata).

Twenty-four Recent species of the boreal-Arctic and Pacific cheilostome bryozoan genus Rhamphostomella are described. The species R. tatarica and R. pacifica are transferred to Rhamphostomella from Posterula and Porella, respectively. Eight species are new: R. aleutica n. sp., R. aspera n. sp., R. commandorica n. sp., R. echinata n. sp., R. microavicularia n. sp., R. morozovi n. sp., R. multirostrata n. sp. and R. obliqua n. sp. Neotypes are selected for six species, and lectotypes for eight species. Mixtoscutella n. gen. is established for several Rhamphostomella-like species, including M. androsovae [formerly Smittina androsovae Gontar], M. cancellata [formerly Escharella porifera forma cancellata Smitt], M. harmsworthi [formerly Schizoporella harmsworthi Waters], M. ovata [formerly Cellepora ovata (Smitt)], and M. ussowi [formerly Schizoporella ussowi (Kluge)]. In addition to taxonomic revision, the morphology (frontal shields, ovicells and multiporous septula), ecology and zoogeography of these cheilostomes are discussed, and identification keys are presented. Most species of Rhamphostomella have broad bathymetric distributions. Some have long protuberances on their basal walls that allow them to grow elevated above allelopathically active substrates such as sponges. The diversity of Rhamphostomella peaks in the northwestern Pacific.

The Cribrilina annulata" problem and new species of Juxtacribrilina (Bryozoa: Cheilostomata: Cribrilinidae) from the North Pacific.

Originally described from Greenland, Juxtacribrilina annulata (Fabricius, 1780) (previously known as Cribrilina annulata) has long been regarded as having a circumpolar, Arctic-boreal distribution. The genus Juxtacribrilina Yang, Seo, Min, Grischenko Gordon, 2018 accommodated J. annulata and three related North Pacific species formerly in Cribrilina Gray, 1848 that lack avicularia, have a reduced (hood-like, cap-like, or vestigial) ooecium closely associated with modified latero-oral spines to form an ooecial complex, and produce frontally or marginally positioned dwarf ovicellate zooids. While the recently described NW Pacific species J. mutabilis and J. flavomaris, which have a vestigial ooecium like a short, flattened spine, clearly differ from J. annulata, the differences between J. annulata and other Pacific populations remained unclear. Here we provide descriptions for five species from the North Pacific region. We identified a specimen from the Sea of Okhotsk as J. annulata. Among the other four species, J. ezoensis n. sp. has a trans-Pacific distribution (abundant at Akkeshi, Hokkaido, Japan; also detected in the Commander Islands and at Ketchikan, Southeast Alaska); J. pushkini n. sp. was found only at Ketchikan; J. dobrovolskii n. sp. was found only at Shikotan Island in the Lesser Kuril Chain; and J. tumida n. sp. was found only at Kodiak, Gulf of Alaska. These four species all differ from J. annulata in having one or two frontal pore chambers on the proximal gymnocyst of most zooids; in budding frontal dwarf ovicellate zooids from these chambers rather than from basal pore chambers; in producing dwarf zooids more abundantly; and in having ooecia that are somewhat to markedly more reduced (cap-like rather than hood-like) and more closely integrated with the modified latero-oral spines. Furthermore, in the Pacific species, the ooecium in basal zooids arises from the roof of the distal pore chamber of the maternal zooid; ovicellate zooids can thus also bud a distal autozooid and are often arranged in columnar series with other zooids. In J. annulata, the hood-like kenozooidal ooecium budded from the maternal zooid replaces the distal autozooid, and ovicellate zooids are thus usually not embedded in a columnar series.

Vasopora ceramica n. gen., n. sp.a new abyssal cyclostome bryozoan from polymetallic nodules in the Russian exploration area, ClarionClipperton Fracture Zone, eastern Pacific Ocean.

A new abyssal cyclostome bryozoan genus and species, Vasopora ceramica n. gen., n. sp., is described from the eastern Russian exploration area of the ClarionClipperton Fracture Zone based on newly collected material from Yuzhmorgeologiya GLD419 station 421 (13.23408 N, 134.22180 W, 4809 m depth). Generic characters include an erect pedunculate colony with a distinct boundary between column and flared capitulum, short autozooidal peristomes in a single whorl, numerous alveoli, a central unidirectional sac-like gonozooid covered by a surficial network of crossed ridges continuous with adjacent rims of alveoli, a laterally opening ooeciopore, and the entire capitulum surface being minutely densely granular to subspinulate. Whereas the skeletal microstructure of the capitulum surface comprises irregular imbricated crystallites, the column has a planar-spherulitic fabric of acicular crystallites in fan-like arrays, and there are no pseudopores. The sharp boundary between capitulum and column, with their different microstructure separates Vasopora n. gen. from the two existing genera of Alyonushkidae that are found in the same environment. Vasopora n. gen. has a stalk formed of calcified exterior wall, whereas it is interior-walled in Alyonushka and Calyssopora.

Morphology of ctenostome bryozoans: 4. Pierrella plicata.

The genus Pierrella was originally created for a single fossil ctenostome bryozoan species from the Late Cretaceous, which is characterized by runner-like colonies, with zooids possessing a distinctive radial, folded aperture. Not long ago, a few specimens of a recent deep-sea congener, Pierrella plicata, were discovered and described from the Russian exploration area of the Clarion-Clipperton Fracture Zone, eastern Central Pacific Ocean. Owing to the lack of data on the internal morphology of this species, we investigated the soft-body morphology of P. plicata using serial sectioning and 3D-reconstruction in order to compare it to other more recently investigated ctenostome bryozoans and to infer the systematic position of the genus. The most striking peculiarity of the examined species is the radial aperture formed by multiple cuticular, pleated folds of the cystid wall. The cuticle is thickened into triangular-shaped folds in this area. An orifical sphincter underlies the folded aperture. Apertural muscles are present as a single pair of parieto-diaphragmatic muscles and four duplicature bands. The remaining polypide anatomy is mainly characterized by its miniature design: the lophophore has eight short tentacles and the digestive tract is one of the shortest and most compact ever observed in any bryozoan. A small intertentacular organ was detected at the lophophoral base. Taken together the genus Pierrella shows unique characters, such as the radial apertural folds that are closed by a series of orificial sphincter muscles, and its particularly small polypide. The general colony morphology resembles arachnidioidean ctenostomes whereas its internal morphology resembles alcyonidioidean species.

Morphology of ctenostome bryozoans: 2. Haywardozoon pacificum, with implications of the phylogenetic position of the genus.

The genus Haywardozoon represent a little known genus of ctenostome bryozoans that has only been found in the deep-sea. It forms small, mostly uniserial colonies lacking polymorphs. Zooids have a conspicuous apertural closure mechanism consisting of a cuticular lower lip that closes the aperture. The systematic placement of the genus remains uncertain, detailed morphological studies that include soft-body morphological traits are missing. Consequently, this is the first study analyzing H. pacificum by means of histological serial sections and 3d-reconstruction. Zooids are ovoid and in some cases solitary, that is, showing no interconnected zooids. Most prominent is the large vestibular wall that can be more than half of the total length of the zooid. Its vestibular wall is particularly lined by a complex, multilayered and branched cuticle. A single pair of lateral parieto-diaphragmatic muscles is present. The polypide is small and comprises about 17 tentacles. The digestive tract is short, has an elongated cardia, a vestigial caecum and a vestibular anus. An ovipositor/intertentacular organ and several oligolecithal oocytes were detected. Several aspects of zooidal morphology, including the structure of the bilateral aperture, parieto-diaphragmatic muscles, general structure of the gut and the thick cuticle, clearly indicate an association to the ctenostome superfamily Alcyonidioidea. Therefore, we reject the previous placement into Hislopioidea and suggest a possible association to pherusellid ctenostomes. New reproductive characters show that H. pacificum is a broadcaster contrary to some other deep-sea forms that are brooding. RESEARCH HIGHLIGHT: Morphology of ctenostome bryozoans remain little investigated. This contribution is the second of a series of detailed morphological analyses of this understudied clade of bryozoans. The morphological investigation of Haywardozoon pacificum revealed numerous characters that show a closer relationship to Flustrellididrae rather than Hislopiidae as previously assumed.

Pandanipora fragilis-a new deep-water cyclostome bryozoan from the subequatorial Mid-Atlantic Ridge, Atlantic Ocean, and a review of Pandanipora worldwide.

A new cyclostome bryozoan, Pandanipora fragilis n. sp., is described from 3453 m depth on the subequatorial Mid-Atlantic Ridge. It differs from the type species, P. helix Grischenko, Gordon Melnik, 2018, by a combination of colonial and zooidal characters. These include regular branching of a uniserial stem along the entire colony length; a straight or just slightly elevated and gently curved distal autozooidal peristomial component, forming a sharp angle with the frontal wall of the next zooid; the pattern of zooidal budding, achieved via development of a partition from the floor of the parent zooid in its distal quarter to third, leaving the proximal portion of daughter zooids not overlapping, so that preceding and subsequent zooids are not appressed along their proximal segments; props are uniformly straight and filiform, with their diameter much smaller than in P. helix; the exceptionally rare presence of slit-like pseudopores, restricted to props; and wedge-shaped crystallites on the internal surface of developing zooids, with irregular, ragged edges. The discovery of P. fragilis suggests that Pandanipora is most likely a relict element of a more-widespread ancient distribution that existed in tropical and boreal zones of both the Atlantic and Pacific Oceans prior to formation of the Isthmus of Panama in the Pliocene.

Erratum: ANDREI V. GRISCHENKO, DENNIS P. GORDON amp; TARAS B. MOROZOV (2018) Fatkullina imitata n. sp., second species of a unique cheilostome bryozoan genus with reversed-polarity zooidal budding, and new family Fatkullinidae. Zootaxa, 4508: 068-084.

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Fatkullina imitata n. sp., second species of a unique cheilostome bryozoan genus with reversed-polarity zooidal budding, and new family Fatkullinidae.

A second species of the unique cheilostome bryozoan genus Fatkullina, with reversed-polarity zooidal budding, has been discovered. Fatkullina imitata n. sp. is described from the western Kamchatka shelf and upper slope of the Sea of Okhotsk. It differs from the type species, F. paradoxa, by the combination of orificial characters, the convex distal third of the frontal shield, and predominantly crimson coloration of dry colonies. A new family, Fatkullinidae, is erected to accommodate Fatkullina (as the type genus) and also Stomacrustula, Pachyegis and Lepralioides. The origin of reversed polarity zooidal budding is considered to arise as a consequence of the unique T-shaped geometry of the ancestrula and transverse daughter zooid followed by spiral budding of periancestrular and succeeding generations of zooids within the zone of astogenetic change.

Bryozoa (Cyclostomata and Ctenostomata) from polymetallic nodules in the Russian exploration area, Clarion-Clipperton Fracture Zone, eastern Pacific Ocean-taxon novelty and implications of mining.

This work describes Bryozoa of the orders Cyclostomata and Ctenostomata found associated with polymetallic nodules collected by box-coring in the eastern part of the Russian exploration area of the Clarion-Clipperton Fracture Zone (CCFZ) under contract to Yuzhmorgeologiya. Scanning electron microscopic study of 358 cyclostome colonies and 14 ctenostome colonies from 4510-5280 m depth has resulted in the recognition of two new species of Ctenostomata, and 14 new species, nine new genera and two new families of Cyclostomata; three additional species of Cyclostomata are left in open nomenclature pending the discovery of missing reproductive characters. The taxonomic novelty is thus notable. One of the new Ctenostomata represents the first living example of the previously monotypic Late Cretaceous genus Pierrella. Twelve of the new cyclostome taxa have well-developed gonozooids, indicating that embryonic cloning (polyembryony) is normal in this deep-sea environment. On the other hand, one indeterminate tubuliporine and two rectangulates have dimorphic peristomes. In the latter two cases, enough mature colonies were found to suggest that this feature is normal, and that the dimorphic zooids are possibly female-in other words, capacious incubation chambers are apparently lacking, and therefore polyembryony would also be lacking or reduced. In one of these species, evidence is presented to suggest that the ancestrular zooid can reproduce precociously. Of the species reported here, only one has previously been found outside the exploration area, highlighting both the limited knowledge we have of bryozoans in the deep Pacific and/or a fauna that is largely endemic to the nodule environment. An additional 31 species of Cheilostomata have also been discovered that will be described in a subsequent publication. Most bryozoans are macrofaunal-sized, so are both inadequately determinable and overlooked in images obtained by remotely operated vehicles; yet, with 50 species, Bryozoa is the most speciose sessile macrofaunal phylum on the nodules. Nodules constitute hard substrata in an area otherwise mostly inhospitable for Bryozoa, hence mining would lead to loss of critical habitat. Further, as suspension-feeders, bryozoans are highly susceptible to smothering by suspended sediment, and non-mined areas closely adjacent to extraction zones would likely also be affected and their associated bryozoan fauna obliterated. More data are required on the distribution of the CCFZ bryozoan species elsewhere in the east Central Pacific to determine if mining would lead to local taxon extirpation or global extinction at both low and high taxonomic levels.

Cribrilinidae (Bryozoa: Cheilostomata) of Korea.

The cribrilinid Bryozoa of Korea are described for the first time. Eight species are recognized, distributed in five genera: Cribrilina, Reginella, Jullienula, Figularia and Puellina. Juxtacribrilina n. subgen. is recognized as comprising a group of species within Cribrilina characterized, inter alia, by having adventitious avicularia, reduced and/or vestigial ooecia, a pair of proportionately long protective latero-oral costae that cross the front of the ooecium and fuse in the midline, and a cribrimorph ancestrula. Cribrilina (Juxtacribrilina) flavomaris n. sp., Jullienula erinae n. sp. and Puellina paracaesia n. sp. are so far known only from the west and southwest coasts of the Korean Peninsula. The following six new combinations are recognized: Cribrilina (Juxtacribrilina) annulata (Fabricius, 1780) n. comb., Cribrilina (Juxtacribrilina) corbicula O'Donoghue O'Donoghue, 1923 n. comb., Cribrilina (Juxtacribrilina) mutabilis Ito, Onishi Dick, 2015 n. comb., Reginella multipora (Sakakura, 1935) n. comb., Reginella biporosa (Okada, 1923) n. comb. and Jullienula ortmanni (Silén, 1941) n. comb.

Megafauna of the UKSRL exploration contract area and eastern Clarion-Clipperton Zone in the Pacific Ocean: Annelida, Arthropoda, Bryozoa, Chordata, Ctenophora, Mollusca.

BACKGROUND: There is growing interest in mining polymetallic nodules from the abyssal Clarion-Clipperton Zone (CCZ) in the tropical Pacific Ocean. Despite having been the focus of environmental studies for decades, the benthic megafauna of the CCZ remain poorly known. To predict and manage the environmental impacts of mining in the CCZ, baseline knowledge of the megafauna is essential. The ABYSSLINE Project has conducted benthic biological baseline surveys in the UK Seabed Resources Ltd polymetallic-nodule exploration contract area (UK-1). Prior to ABYSSLINE research cruises in 2013 and 2015, no biological studies had been done in this area of the eastern CCZ. NEW INFORMATION: Using a Remotely Operated Vehicle and Autonomous Underwater Vehicle (as well as several other pieces of equipment), the megafauna within the UK Seabed Resources Ltd exploration contract area (UK-1) and at a site ~250 km east of the UK-1 area were surveyed, allowing us to make the first estimates of megafaunal morphospecies richness from the imagery collected. Here, we present an atlas of the abyssal annelid, arthropod, bryozoan, chordate, ctenophore and molluscan megafauna observed and collected during the ABYSSLINE cruises to the UK-1 polymetallic-nodule exploration contract area in the CCZ. There appear to be at least 55 distinct morphospecies (8 Annelida, 12 Arthropoda, 4 Bryozoa, 22 Chordata, 5 Ctenophora, and 4 Mollusca) identified mostly by morphology but also using molecular barcoding for a limited number of animals that were collected. This atlas will aid the synthesis of megafaunal presence/absence data collected by contractors, scientists and other stakeholders undertaking work in the CCZ, ultimately helping to decipher the biogeography of the megafauna in this threatened habitat.

Intertidal Bryozoa from Korea-new additions to the fauna and a new genus of Bitectiporidae (Cheilostomata) from Baengnyeong Island, Yellow Sea.

Eight species are added to the intertidal bryozoan fauna of South Korea, all collected from the extreme northwestern part of the country at Baengnyeong Island. Five of the species (Hippothoa imperforata, Celleporella hyalina, Celleporella nodasakae, Porella donoghueorum and Suhius rubescentis) are new records. Cauloramphus dicki n. sp., Cauloramphus spencerjonesae n. sp., and Exochella cryptodontia n. sp. are new to science; Suhius n. gen. is a newly recognized genus in Bitectiporidae. The close morphological similarity of umbonuloid-shielded P. donoghueorum to Australasian and Antarctic species of lepralioid-shielded species of Aimulosia is discussed in relation to ascophoran phylogeny. The described cheilostome fauna from South Korea is herein increased to 121 species.

Systematics of some calloporid and lacernid Cheilostomata (Bryozoa) from coastal South Korean waters, with the description of new taxa.

Six species in two families of Cheilostomata-Calloporidae and Lacernidae-are described from the southern coasts of the Korean Peninsula, resulting in a new distributional record and four new species to the Korean fauna. Further, Woosukia n. gen. is described, based on an existing species. Two species names (Crassimarginatella crassimarginata and Arthropoma cecilii) are deleted from the Korean faunal list owing to previous misidentification, with the net result that the Korean cheilostome fauna is increased to 125 species. The new additions to the fauna are: Crassimarginatella kumatae (Okada), Retevirgula asiana n. sp., Woosukia subhexagona (Ortmann), Arthropoma magniporosum n. sp., Arthropoma minus n. sp., and Phonicosia crena n. sp. The biogeographic relationships of some western Pacific taxa are discussed.

Two new species of the cheilostome bryozoan Cheilopora from the Aleutian Islands.

Two new species of Cheilopora-C. peristomata and C. elfa-are described from the shallow water around Adak and Amchitka of the Andreanof and Rat island groups of the Aleutian Islands. Zooids of both new species have cormidial peristomes, composed by the distal (originating from neighbouring zooid) and proximal lappets. In contrast to previously described species, the strongly elevated peristomial lappets defining the secondary orifice confer the overall shape of an incomplete circle with deep U-shaped proximolateral pseudosinuses. Depending on angle of view, this gives a campanuliform or trifoliate outline to the secondary orifice, by which the new species differ from congeners. Together with previous discoveries from the Aleutians, these two new Cheilopora species are indicative of incomplete knowledge of the marine biodiversity of the region, including the distinctive character of the bryozoan fauna. There is a need for intensification of taxonomic effort along the island arc.

Cribrimorph and other Cauloramphus species (Bryozoa: Cheilostomata) from the Northwestern Pacific.

We provide original descriptions for nine new species in the cheilostome bryozoan genus Cauloramphus (C. gracilis, C. Ordinarius, C. amphidisjunctus, C. cheliferoides, C. oshurkovi, C. infensus, C. parvus, C. peltatus, and C. ascofer) and a redescription of C. disjunctus Canu and Bassler, 1929 . We delineate a group of eight species, here termed the 'C. disjunctus clade,' that have the opesial spine joints calcified to a greater or lesser extent in mature zooids; most also have paired, hypertrophied avicularia. This group includes C. amphidisjunctus, C. cheliferoides, C. infensus, C. parvus, C. peltatus, and C. ascofer in the Aleutian Islands, Alaska; C. oshurkovi in the Commander Islands; and C. disjunctus in Japan. High levels of apparent endemism in two unrelated bryozoan genera (Cauloramphus and Monoporella), and geographical population differentiation in C. ascofer indicating ongoing allopatric speciation, suggest high speciation rates for deep benthic bryozoans in the western Aleutians. A phylogenetic hypothesis for the C. disjunctus clade indicates that populations of Cauloramphus dispersed between the Aleutians and Asia on at least three separate occasions, and that the polarity of at least two of these dispersal events was from the Aleutians to Asia.

Comparative anatomical study of internal brooding in three anascan bryozoans (Cheilostomata) and its taxonomic and evolutionary implications.

The anatomical structure of internal sacs for embryonic incubation was studied using SEM and light microscopy in three cheilostome bryozoans-Nematoflustra flagellata (Waters,1904), Gontarella sp., and Biflustra perfragilis MacGillivray, 1881. In all these species the brood sac is located in the distal half of the maternal (egg-producing) autozooid, being a conspicuous invagination of the body wall. It consists of the main chamber and a passage (neck) to the outside that opens independently of the introvert. There are several groups of muscles attached to the thin walls of the brood sac and possibly expanding it during oviposition and larval release. Polypide recycling begins after oviposition in Gontarella sp., and the new polypide bud is formed by the beginning of incubation. Similarly, polypides in brooding zooids degenerate in N. flagellata and, sometimes, in B. perfragilis. In the evolution of brood chambers in the Cheilostomata, such internal sacs for embryonic incubation are considered a final step, being the result of immersion of the brooding cavity into the maternal zooid and reduction of the protecting fold (ooecium). Possible reasons for this transformation are discussed, and the hypothesis of Santagata and Banta (Santagata and Banta1996) that internal brooding evolved prior to incubation in ovicells is rejected.

Doryporella smirnovi sp. nov. (Bryozoa: Cheilostomata) and its impact on phylogeny and classification.

A new species of Doryporella, D. smirnovi sp. nov. is described from the area of the Commander Islands. Inclusion of this species in a revised phylogenetic analysis of Doryporella and its relatives permits the recognition of a clade comprising Doryporella and Doryporellina. This clade is accorded family-level status as the Doryporellidae fam. nov., thereby removing Doryporella (and Doryporellina) from the large and paraphyletic Calloporidae.

A new cheilostome bryozoan with gigantic zooids from the North-West Pacific.

Gontarella gigantea gen. et sp. nov. is described from two stations, one in the Sea of Okhotsk and the second on the Pacific side of the Small Kuril Arc. This membraniporiform anascan cheilostome bryozoan has very large zooids, the largest known among extant sheet-like encrusting anascans. Comparative data on similar sheet-like cheilostomes gathered from the literature shows that the new species represents a conspicuous outlier in size, with the surface area of the zooid being approximately twice that of the next largest species. Skeletal evidence, including the lack of ovicells, indicates that G. gigantea belongs within the malacostegan family Electridae. The gigantic ancestrula suggests that the species has a cyphonautes larva about 1 mm in maximum dimension.