Larval Behavior and Post-Larval Development in Parasmittina nitida Morphotype B (Bryozoa: Cheilostomata)

Larval behavior and metamorphosis in Parasmittina nitida morphotypeB from the Gulf of Mexico has been studied. The larvae havetwo basic types of movement: (1) a clockwise-counterclockwisemovement about the aboral-oral axis of the lobular larval formresulting in either slow horizontal or rapid vertical movement,and (2) a directed horizontal movement of the creeping larvalform, whereby either the oral lobe is pressed against the substrateor the aboral-oral axis is tilted forward. In both forms, thevibratile plume of the pyriform organ complex extends the leadingedge of the larva. Metamorphosis was observed with Nomarskidifferential interference microscopy in living specimens andwith scanning electron microscopy in fixed specimens. Polypidedevelopment— in particular, the formation and diminutionof the nutritive mass, the differentiation of the polypide rudiment,diaphragm, vestibular glands, operculum, major components ofthe musculature and alimentary canal, and the early stages ofastogenetic growth—is described. The tata ancestrula ofthis species is characterized by a frontal wall calcified distallyto the aperture, which is surrounded by nine erect spines. Thepolypide feeds actively within seven to eight days after theonset of larval attachment and metamorphosis under laboratoryconditions of 22°C.     

Colony–Substratum Relations in Scrupocellariidae (Bryozoa, Cheilostomata)

In the Bryozoa in general the colony is attached by means of the primary zooid, the ancestrula, which is permanently cemented to the substratum. The attachment is brought about, in the marine bryozoans, by the larva everting its interior sac into a basal adhesive disc secreting a thin layer of hardening mucus. In Scrupocellaria reptans no adhesive disc was found. The metamorphosing larva is fixed to the substratum by a column of loose, sticky secretion. This primary fixation is ephemeral and replaced by a secondary, permanent fixation by one pair of rootlets. Thus, the ancestrula body proper and the colony arising from it become permanently free from the substratum but anchored to it by rootlets, the primary pair and series of secondary rootlets. This unique and certainly secondarily evolved type of attachment is apparently realized in the Scrupocellariidae in general, to a more or less perfect degree. It appears as one of several possible models to meet efficiently with environmental disturbances.     

Systematic notes on some Antarctic Ascophora (Bryozoa, Cheilostomata)

Nine new species of ascophoran cheilostome Bryozoa are described from Antarctic localities. Five species are considered to be new to science ( Smittina favulosa, Smittina diffidentia, Smittoidea pugiuncula, Escharella mamillata, Fenestrulina antarctica ), while four others have been previously recorded under other names ( Smittoidea malleata, Escharella watersi, Lacerna watersi, Hippothoa belgica ). Escharella crozetensis Waters, formerly recorded from Antarctica, is considered to be limited to the Kerguelen region of the South Indian Ocean.     

Notes on some species of Parasmittina Osburn, 1952 (Bryozoa: Cheilostomatida)

Nine species of the cheilostomate bryozoan genus Parasmittina Osburn, 1952, are described. Neotype specimens are selected for P. parsevalii (Audouin) and P. raigii (Audouin). P. hastingsae Soule and Soule, P. agathae sp. nov., P. parsloeparsloei sp. nov., P. pectinata sp. nov. and P. solenosmilioides sp. nov. are described from Australian localities. P. fistulata (Harmer) is redescribed and P. decorata Soule and Soule is placed in the synonymy of P. delicatula (Busk).     

Some Antarctic and sub-Antarctic species of Celleporidae (Bryozoa, Cheilostomata)

Sixteen species of cheilostome Bryozoa, within the family Celleporidae Busk, 1852, are reported from Antarctica and the sub-Antarctic south-west Atlantic. Nine new species are described in the genera Osthimosia Jullien, 1888, Celleporina Gray, 1848 and Turbicellepora Ryland, 1963. Spigaleos gen. nov. is introduced for Cellepora horneroides Waters, 1904.     

Cryptic species in the cosmopolitan Bugula neritina complex (Bryozoa,Cheilostomata)

Previous analyses of the mitochondrial gene cytochrome c oxidase subunit 1 (COI) and γ‐proteobacterial endosymbiont diversity have suggested that the marine bryozoan Bugula neritina is a complex of three cryptic species, namely Types S, D and N. Types D and N were previously reported to have restricted distributions along California (western USA) and Delaware and Connecticut (eastern USA), respectively, whereas Type S is considered widespread in tropical, subtropical and temperate regions due to anthropogenic transport. Here, Bayesian species delimitation analysis of a data set composed of two mitochondrial (COI and large ribosomal RNA subunit [16S]) and two nuclear genes (dynein light chain roadblock type‐2 protein [DYN] and voltage‐dependent anion‐selective channel protein [VDAC]) demonstrated that Types S, D and N correspond to three biological species. This finding was significantly supported, in spite of the combinations of priors applied for ancestral population size and root age. Furthermore, COI sequences were used to assess the introduction patterns of the cosmopolitan Type S species. Two COI haplotypes of Type S (S1a and S1d) were found occurring at a global scale. Mantel tests showed correlation between these haplotypes and local sea surface temperature tolerance. Accordingly, the distributions of Type S haplotypes may reflect intraspecific temperature tolerance variation, in addition to the role of introduction vectors. Finally, we show that the Type N may also have been introduced widely, as this species was found for the first time in Central California and north‐eastern Australia.     

Growth aspects of Flustra foliacea(Bryozoa, Cheilostomata) in laboratory culture

Flustra foliacea is a cheilostome marine bryozoan which, after initial horizontal growth during the first year, changes to erect growth thereafter. Appraising this slow-growing species for biotechnological use, required the development of cultivation methods for economical biomass production. Vegetative reproduction via cuttings, as employed in the horticulture of various plants, was tested. Fronds of F. foliacea were cut into pieces (10–150 mg fresh weight) and fixed in longitudinally cut silicon tubes. Bryozoa were fed with a mixture of Isochrysis galbana, Dunaliella tertiolecta and Cryptomonas sp. yielding growth rates of 0.3% ± 0.02 day^?1of the initial fresh weight. Growth of the colony occurred firstly at the original growth margin, but later also at the transections, including the side fixed in the silicon tube, opposite to the growth margin. After three months of growth, the two layers of zooids split at the growth margin, forming two monolayers. This growth feature, not described previously for Flustra foliacea,was observed under experimental and natural conditions, and is interpreted as the beginning of one type of ramification. According to our findings, vegetative reproduction of F. foliacea under laboratory conditions is possible and might be an alternative to natural resources regarding biomass of this species.     

Petraliellidae Harmer, 1957 (Bryozoa: Cheilostomata) from Queensland,Australia

Several species of the family Petraliellidae were first described from the coast of Queensland, including the type species of Sinupetraliella, S. litoralis. These species are redescribed from type, or topotype specimens, and include Petraliella concinna, which has not been certainly found since its introduction in 1891; lectotype material is designated for P. buski and P. magna. Six other species are described from Queensland, P. crassocirca, P. dentilabris, P. dorsiporosa, Mucropetraliella bennetti, M. serrata and M. tuberosa. The species Mucropetraliella tuberosa is a new addition to the Queensland fauna and is described and illustrated here for the first time since its introduction in 1884. The characters of the family Petraliellidae are briefly discussed and the genera to which the Queensland species are assigned is reviewed. A taxonomic key to the ten Queensland petraliellid species described is also provided.     

Systematic notes on some British Ascophora (Bryozoa: Cheilostomata)

A review of the British ascophoran cheilostomes has revealed several instances of synonymic confusion, and necessitated the introduction of two new generic names. Porelloides gen. nov. is instituted for two species formerly included in Porella , with P. laevis (Fleming) as type species, and Phaceostachys gen. nov. is introduced for Lepralia spinifera Johnson. Smittoidea amplissima sp. nov. was hitherto not distinguished from Smittina landsborovii (Johnston). Porella minuta (Norman), reported from localities as far afield as the western Mediterranean and the Canadian Arctic, is shown to comprise two species, and the northern records are here attributed to P. alba Nordgaard. Exharella labiosa (Busk) and E. klugei sp. nov. (=E. ventricosa var. peristomata Kluge) are redescribed, and E. laqueata and E. abyssicola are discussed. The case for retaining Cellepora Linnaeus is argued and Lepralia quincuncialis Norman is referred to Buskea Heller.     

Body wall morphology of Pentapora foliacea (Ellis and Solander) (Bryozoa,Cheilostomata)

The ascophoran Pentapora foliacea was studied from epoxy sections of skeletal and soft (hard-soft) tissues. The basal wall is double, indicating the colony grew as two independent layers, back to back. The structure of the vertical walls and interzooidal communication organs indicates that zooids were budded in the usual way as in most encrusting cheilostomes. Secondary layers of the frontal wall are of acicular aragonite. The ovicell develops as a flattened cuticular bladder in early ontogeny; the aragonitic layer of the frontal wall later engulfs it. A median vesicle, an evagination of the vestibular wall, is present but the eggs may be supplied with sufficient yolk to nurture the embryo. The overall ovicell structure is similar to that of hyperstomial ovicells in other cheilostomes.     

Morphological and molecular concordance of Rhynchozoon clades (Bryozoa, Cheilostomata) from Alaska

Abstract. Alpha‐level taxonomy in the bryozoan order Cheilostomata relies almost exclusively on hard‐part morphology. Geographical, ecophenotypic, and intracolony variation often make it difficult to distinguish intra‐ from interspecific variation and to recognize taxonomically informative characters. DNA sequences provide a source of data independent of morphology by which to gauge the relative reliability of various morphological characters for taxonomy. We present a case study involving a limited number of specimens of Rhynchozoon sp. from Ketchikan, Alaska to show the utility of DNA data in identifying genetic lineages for subsequent morphological analysis. The study illustrates that the use of genetic data need not involve massive, broad‐scale phylogenetic studies to address problems in invertebrate α‐level taxonomy. Phylogeny reconstruction with a 430‐bp fragment of the 16S mitochondrial ribosomal RNA gene showed two moderately diverged clades, here termed Rhynchozoon clades A and B, separated by an average genetic distance of 2.38% (K2P+Γ). Comparison of voucher specimens by scanning electron microscopy showed two congruent, morphologically distinct forms (forms A and B, respectively) distinguishable by a polythetic suite of characters including degree of frontal costation, range of spine number, number of beads on the primary orifice, number of areolar pores, and peri‐orificial sculpturing. Orifice shape and ovicell form proved not to be good diagnostic characters. The status of the two forms as biological species is unclear, although maintenance of distinct suites of morphological characters in the two mitochondrial lineages suggests they may be reproductively isolated from one another. For Rhynchozoon form B, which tends to have a highly costate frontal wall, we suggest a resurrection of the name Rhynchozoon tumulosum, which had been previously synonymized with R. rostratum. Rhynchozoon form A may be conspecific with “Rhynchozoon sp. A” previously reported from Washington state.     

Some Antarctic and sub-Antarctic species of Smittinidae (Bryozoa: Cheilostomata)

Twenty-six species of Bryozoa, in the ascophoran cheilostome family Smittinidae Levinsen, 1909, are described from Antarctic and sub-Antarctic localities. Fourteen species are considered to be new to science. Aspericreta gen. nov. is introduced for Smittina crassatina Waters, 1904, and Platychelyna gen. nov. for Cellarinella planulata Hayward, 1980.     

Systematic studies on some Antarctic and sub-Antarctic Ascophora (Bryozoa: Cheilostomata)

Twenty-two species of ascophoran cheilostome Bryozoa are described and figured from Antarctic and sub-Antarctic localities. Ten new species are described in the genera Exochella, Buffonellodes and Hippadenella. Ralepria gen. nov. is introduced for Ralepria conforma sp. nov., and Trilochites gen. nov. is introduced for Escharoides biformata Waters, 1904. Five species described by Jullien (1888) and Calvet (1909) are redescribed following re-examination of type specimens.     

Sexual reproduction of the placental brooder Celleporella hyalina (Bryozoa,Cheilostomata) in the White Sea

The evolution of parental care is a central field in many ecological and evolutionary studies, but integral approaches encompassing various life-history traits are not common. Else, the structure, development and functioning of the placental analogues in invertebrates are poorly understood. Here, we describe the life-history, sexual colony dynamics, oogenesis, fertilization and brooding in the boreal-Arctic cheilostome bryozoan Celleporella hyalina. This placental brooder incubates its progeny in calcified protective chambers (ovicells) formed by polymorphic sexual zooids. We conducted a detailed ultrastructural study of the ovary and oogenesis, and provide evidence of both auto- and heterosynthetic mechanisms of vitellogenesis. We detected sperm inside the early oocyte and within funicular strands, and discuss possible variants of fertilization. We also detail the development and functioning of the placental analogue (embryophore) in the various stages of embryonic incubation as well as embryonic histotrophic nourishment. In contrast to all known cheilostome placentas, the main part of embryophore of C. hyalina is not a single cell layer. Rather, it is a massive “nutritive tissue” whose basal part is associated with funicular strands presumably providing transport function. C. hyalina shows a mixture of reproductive traits with macrolecithal oogenesis and well-developed placenta. These features give it an intermediate position in the continuum of variation of matrotrophic provisioning between lecithotrophic and placentotrophic cheilostome brooders. The structural and developmental differences revealed in the placental analogue of C. hyalina, together with its position on the bryozoan molecular tree, point to the independent origin of placentation in the family Hippothoidae.     

Epibiont foraminifera of Sertella frigida (Waters) (Bryozoa, Cheilostomata) from Terranova Bay, Ross Sea, Antarctica

Several arenaceous and calcareous foraminifera epibionts of Sertella frigida (Waters) (Bryozoa, Cheilostomata), collected in Terranova Bay during the 1989–90 Italian Antarctic expedition, were studied. Arenaceous species, such as Psammosphaera fusca Schulze f. adhearescens Rhumbler, Haplophragmoides canariensis d'Orbigny, Portatrochammina antarctica (Parr), and Trochammina arctica Hedley, Hurdle and Burdett, are a conspicuous component of the epifaunal community. The calcareous foraminifers encrusting S. frigida are mostly represented by Cibicides refulgens Montfort and Rosalina globularis d'Orbigny. Foraminifera were found only in the basal part of the bryozoan colonies. The presence of many juveniles provided evidence that foraminifers were reproducing at the time of sampling. Psammosphaera fusca f. adhaerescens was found exclusively inside the zooids of S. frigida. The large number of individuals associated with the bryozoan suggest that P. fusca f. adhaerescens finds optimum conditions (shelter, food, and grains for shell building) for growth inside the zooids of S. frigida. The other species occurred most commonly adhered to the trabeculae or to the zooid orifices of S. frigida. An elevated position offers a better chance to catch food particles from the overlying water column. Foraminifers could benefit also from bryozoan feeding currents. The availability of resuspended organic material could provide a more consistent source of food in a highly seasonal oligotrophic environment. Received: 8 February 1995/Accepted: 30 June 1996     

New celleporid (Bryozoa,Cheilostomata) species from Tertiary deposits of western Kachchh,Gujarat, India

Five new bryozoan species (Buffonellaria cornuta, Lagenipora chedopadiensis, Turbicellepora canui, T. naniberensis andT. rostrata) belonging to the family CelleporidaeHINCKS, 1884 are described and illustrated from the Tertiary sequences of western Kachchh, Gujarat, India. The zoaria of these species comprise about 17 percent of total cheilostome bryozoan colonies from Kachchh in the present collection, and those ofTurbicellepora rostrata n. sp. account for over 64 percent of the celleporid specimens. These records of celleporids enrich our knowledge of the fossil occurrence of this group during the Early Miocene in the Indo-Pacific province.