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Synopsis Who needs to go to outer space to study alien beings when the oceans of our own planet abound with bizarre and unknown creatures? Many of them belong to sessile clonal and colonial groups, including sponges, hydroids, corals, octocorals, ascidians, bryozoans, and some polychaetes. Their life histories, in many ways unlike our own, are a challenge for biologists. Studying their ecology, behavior, and taxonomy means trying to 'think like a colony' to understand the factors important in their lives. Until the 1980s, most marine ecologists ignored these difficult modular organisms. Plant ecologists showed them ways to deal with the two levels of asexually produced modules and genetic individuals, leading to a surge in research on the ecology of clonal and colonial marine invertebrates. Bryozoans make excellent model colonial animals. Their life histories range from ephemeral to perennial. Aspects of their lives such as growth, reproduction, partial mortality due to predation or fouling, and the behavior of both autozooids and polymorphs can be studied at the level of the colony, as well as that of the individual module, in living colonies and over time. doi: 10.1093/icb/icq146

To quantify and explore the role of temperature on population outbreaks of a nonindigenous bryozoan (Membranipora membranacea) in kelp beds in the western North Atlantic (Nova Scotia, Canada), we constructed an individual-based model using field-derived estimates for temperature-dependent colony settlement and growth. Using temperature as the single input variable, the model successfully simulated the timing of onset of settlement, colony abundance, colony size, and coverage on kelps. We used the model to examine the relative effect on the population of varying temperature by -2[degrees]C to +2[degrees]C each day. The timing of onset of settlement varied by 18 d [degrees]C 1 with changes in temperature from January to August. Variations in temperature had nonlinear effects on the population, with an increase in daily temperature of I[degrees]C and 2[degrees]C causing the cover of colonies on kelps to increase by factors of 9 and 62, respectively. Changes in winter and spring temperature had the most pronounced effects on the timing and abundance of colonies, while changes in summer temperature had the most pronounced effect on colony size and coverage on kelp blades. Outbreaks of this species will increase in frequency and intensity if temperatures warm as a result of climate change, causing defoliation of kelp beds and, thus, facilitating the invasion of other nonindigenous benthic species. doi: 10.4319/10.2010.55.4.1627

Bryozoans are suspension feeding colonial animals that remain attached to the substratum or other surfaces. How well a bryozoan can feed in a particular flow regime could help determine the distribution and abundance of that bryozoan. I tested how velocity of flow affects feeding rate in four species of bryozoans in the laboratory and how these species perform in different flow regimes in the field. I found that one species, Membranipora membranacea, had a higher ingestion rate than did the other three species at all velocities of flow tested. Mernbranipora also had a higher rate of ingestion at intermediate velocities, while velocity did not have as strong an effect on ingestion rate in the other three species. As predicted from the feeding experiments, all four species generally had greater abundance, attained a larger size, grew faster, and survived longer in flow regimes in which feeding is higher. Also as predicted, Membranipora had greater abundance, attained a larger size, grew faster, and survived longer than did the other three species both in slower and faster flow regimes in the field. Understanding how flow affects feeding can help predict the distribution and abundance of bryozoans in the field. Because especially efficient filterers like Membranipora can grow faster and have higher survival under a wide range of conditions of flow, this species may be able to outcompete many other species or take advantage of ephemeral habitats, thereby becoming a potentially effective invasive species as has been seen in the Gulf of Maine.

The bacterial symbionts of Watersiporia arcuata are analyzed for their phylogeny. The symbionts of different Watersiporia species were found to be closely related species of [alpha]-proteobacteria.

Metrarabdotos Canu, 1914 and the related genera Escharoides Milne Edwards, 1836b, Adeonellopsis MacGillivray, 1886, and Reptadeonella Busk, 1884 were key taxa in the decline of Bryozoa with erect, arborescent colonies and concomitant increase in numbers of species with encrusting colonies in the late Paleogene and Neogene of tropical America. In particular, the abundance, continuity of occurrence, and diversity of Metrarabdotos before its decline have made this genus, over the past 20 years, a model taxon for detailed morphometric studies of fine-scale evolutionary tempo and mode. During the same period, significant new occurrences of both Metrarabdotos and its near relatives have been documented with detailed collections from tropical American areas not represented in the original studies. In this paper we present a complete reanalysis of the original morphometric data (Cheetham, 1986a), incorporating the new tropical American material and comparative material of selected Metrarabdotos species from Europe and Africa in order to formalize the taxonomy of the genus, many species of which have been in open nomenclature since 1986, and to explore their possible phylogenetic relationships to each other and to Escharoides, Adeonellopsis, and Reptadeonella. The new analysis, with procedures slightly modified from those used in the original analysis, is based on more than twice the number of specimens and 20% more morphological characters. Although the results include changes in species assignments for 13% of the specimens in the original analysis, the pattern of intraspecific morphological stasis previously identified in the tropical American Neogene species, and thus the concomitant interpretation of evolutionary tempo and mode, are unaltered. Cladistic analysis resulted in a single most parsimonious tree for the 22 tropical American Metrarabdotos species, arranged in two monophyletic crown groups and a paraphyletic stem group. The stem group, ranging from latest Eocene to late Early or early Middle Miocene in age, includes four species, two of which are new: M. aguilerai from Venezuela and M. hispaniolae from the Dominican Republic and Haiti. Crown group A comprises seven species occurring in deposits of Late Miocene to Recent age, four of which are new: M. arawakorum from Venezuela; M. boldi and M. saundersi from the Dominican Republic; and M. coatesi, which occurs in the Dominican Republic, Costa Rica, and Panama. Crown group B, comprising 11 species, ranges from Early Miocene to Recent and includes five new species: M. cubaguaense from Venezuela; M. vokesorum from the Dominican Republic, Costa Rica, and Panama; and M. tainorum, M. jungi, and M. lopezense from the Dominican Republic. Incorporation of six European and African (eastern Atlantic) species, ranging in age from Early Miocene to Recent, into cladograms with the tropical American species produced more variable results in terms of both numbers of alternative trees and the positions of the tropical American species in them. One of these species, M. thomseni from the Pleistocene of Greece, and possibly a second, M. cf. M. maleckii Cheetham, 1968 from the Miocene of the Czech Republic, are new. With one exception, the eastern Atlantic species were placed in more or less basal positions in one or the other of the crown groups, suggesting that, as hypothesized by Cheetham (1968), the 'Old World' and 'New World' species of Metrarabdotos represent largely independent radiations. The exception is the living species M. cookae Cheetham, 1968, from West Africa and the Cape Verde Islands, which is placed unequivocally in a terminal position in crown group B. Although the three groups of tropical American species correspond in part to subgenera of Metrarabdotos erected by Cheetham (1968), the paraphyly of the stem group and the unresolved identity of the type species of the subgenus apparently corresponding to crown group A suggest that formalizing the taxonomy of these groups is unwarranted at present. A further cladistic analysis, incorporating the three groups of Metrarabdotos species and Escharoides, Adeonellopsis, and Reptadeonella, yielded two trees, both of which support Cheetham's (1968) hypothesis that Metrarabdotos is more closely related to Escharoides than to Adeonellopsis and Reptadeonella. Escharoides is represented in tropical American Neogene deposits by two species, one of which, E. guraboensis from the Dominican Republic, is new. Of the six tropical American Neogene species of Adeonellopsis, four are new: A. cribrospiramen and A. guraboensis from the Dominican Republic, A. limonensis from Costa Rica, and A. antilleana from Cuba and Jamaica. Three of the six tropical American Neogene species of Reptadeonella, R. buddae from the Dominican Republic, R. collinsae from the Dominican Republic, Panama, Costa Rica, and the southeastern United States, and R. buricaensis from Panama, are also new.

Two gene fragments from B. neritina larvae that have high levels of similarity to polyketide synthase genes are isolated. A clear association of these gene fragments with the symbiont is found and no association is found with the host.

Six new species of fenestrate bryozoans, middle to late Wordian, occur in the Gerster Limestone of northeastern Nevada. These bryozoans are similar to lower Kazanian species described from the Russian Platform. The two species of Wjatkella and Polypora from the Gerster Limestone are much more similar to the Russian species than they are to the two species recently described from the allochthonous late Wordian Mission Argillite of northeastern Washington. New species described from the Gerster Limestone are Rectifenestella cordiretiformis, Wjatkella hemiseptifera, Kingopora wardlawi, Kingopora inflata, Polypora keyserlingiformis, and Polyporella helgersoni. The presence of only six species of fenestrate bryozoans in nearly 260 m of limestone and siltstone is notable.

For many sedentary or sessile benthic marine invertebrates the planktonic duration of the larval stage is believed to be a key determinant of the magnitude of genetic differences between populations. An obvious dichotomy in dispersal potential exists within cheilostome bryozoans that develop from either (1) a cyphonautes larva that spends several weeks in the plankton or (2) a brooded coronate larva that settles soon after release from the adult colony. This study characterizes the pattern of variation at allozyme loci among British populations of four species of bryozoan--two species with cyphonautes and two with coronate larvae. There is some variation in the estimates of genetic differentiation among similarly separated populations that may be a consequence of non-equilibrium genetic conditions arising from sporadic migration, possibly through dispersal by rafting on macroalgae by mature colonies. Despite this, however, both the level of genetic differentiation between populations and the pattern of migrant exchange correlate with the larval developmental mode. Bryozoan species that brood coronate larvae show higher levels of genetic heterogeneity between populations and significant isolation by distance genetic structure while, by contrast, distance has little or no effect upon the amount of genetic differentiation among populations of bryozoans with cyphonautes larvae. For cheilostome bryozoans, therefore, it appears that genetic differentiation between populations is directly associated with the type of larval development. These data are discussed also with respect to levels of gene diversity and the geological pattern of cheilostome bryozoan species diversity., Introduction Dispersal capability is a key life-history trait that impacts upon metapopulation dynamics (Hanski 1999) and the spatial scale of genetic differentiation (Wright 1943), thereby shaping the pace of evolutionary [...]

Zooid size variation and growth banding in the bryozoan Pentapora fascialis, collected from the South of Great Britain to the South of Italy, were investigated in order to test their relationship with the variation of seawater temperature. Zooid length appeared to be more sensitive than zooid area and width to temperature variation. The longest zooids were budded in localities that typically experience low seasonal variation in temperature (3.2-7.5[degrees]C) and low mean annual temperature (about 11[degrees]C). Zooid length demonstrated the strongest relationship with the range of seasonal variation in temperature rather than the mean annual temperature. Growth bands produced during colder months were less high than those produced during warmer months. Measurements of these alternating bands were used to calculate growth rate of the laminae, ranging from 20.7 at Plymouth to 29.3 mm yea[r.sup.-1] at Tino Island. Significant differences in zooid length were found between the two bands, with longer zooids within the band developed in colder months and shorter zooids in bands produced in the warmer period. We conclude that zooid size can be used as an environmental proxy of the seasonal temperature regimes experienced by the species., Introduction Many taxa, including both ectotherms and endotherms, as well as solitary and colonial forms, show an inverse relationship between body size and ambient temperature experienced during their growth. Notwithstanding [...]

Discovery of avicularium-like polymorphs in Wilbertopora mutabilis Cheetham, 1954 has provided not only a new opportunity for revising the genus Wilbertopora Cheetham, 1954, but also a more detailed basis for documenting the series of morphological changes by which avicularia differentiated from ordinary feeding zooids in what appears to be the first occurrence of these characteristic cheilostome bryozoan structures in the fossil record. Eighteen of a total 60 quantitative characters measured on avicularia and ordinary and ovicell-bearing autozooids were sufficient to distinguish eight species of Wilbertopora by discriminant function analysis of zooid data from 93 colonics from the mid-Cretaceous (Albian-Cenomanian) Washita Group in northeastern Texas and southeastern Oklahoma. Eighteen of a total of 20 of the quantitative characters that could be statistically coded for cladistic analysis proved to be informative with respect to parsimony, providing two maximally parsimonious trees for the eight species. Two-thirds of the diagnostic characters involve avicularia. An additional 55 colonies too poorly preserved for morphometric analysis could then be assigned to species qualitatively, with 170 more colonies lacking species-diagnostic characters. The cladistic trees strongly suggest that most or all of the species diverged before the end of the Albian, but stratigraphic resolution is insufficient to test this hypothesis. Nevertheless, the series of morphological changes differentiating avicularia from ordinary autozooids in these species, based on the cladistic relationships, is highly significant statistically, and may be a pattern later repeated in other cheilostomes. Wilbertopora and W. mutabilis are emended, and seven new species are described: W. listokinae. W. tappanae. W. spatulifera, W. attenuata, W. improcera, W. acuminata, and W. hoadlevae.

Mediterranean populations of Schizobrachiella sanguinea seem to span a wide range of contrasting benthic habitats. We have studied adult, larval, and recruit populations of S. sanguinea from sublittoral (approximately 10 m depth) communities at Blanes (Spain, NW Mediterranean). At the study site, the species colonises semi-obscure caves and, to a lesser extent, communities of sciaphilic algae. Our first goal was to show the periods of brooding, larval release, and recruitment. Plankton was collected about twice a week between July 1998 and June 2000 over an artificial reef. A total of 303 larvae were collected in 23 of the 102 days of sampling. At the study site the species shows a single, annual larval release period, which occurs from late March to June July every year. Recruits were found from late May to late August 1999 and in late May 2000. A recruitment peak was observed in July 1999 and again in late May 2000. The presence of brooding adults corresponded to the periods of larval supply and recruitment. Our second goal was to investigate the causes of the variable distribution of the species along several communities in the north-west Mediterranean Sea. We describe adult distribution and the dynamics of larval supply, recruitment of early ([less than or equal to] 15 days from settlement) and late ([less than or equal to]4 months from settlement) recruits. Patterns of larval presence and early recruit distribution along the communities on the reef did not reflect the adult distributions, whereas this was closely matched by the distribution of late recruits. Post-recruitment mortality strongly affected recruits of the PA (photophilic algae) and SA (sciaphilic algae) communities, whereas it was very low in the communities of SOC (semi-obscure caves). Mortality of recruits was density independent and colony survivorship in the SA communities, where recruitment was the highest, appeared strongly affected by competition with brown algae. Like the majority of cheilostomate bryozoans, S. sanguinea releases a coronate larva capable of active swimming and positive reaction to light. Such swimming abilities may allow larvae to actively select the substrate on which to settle and to avoid unsuitable substrates. It seems that larval behaviour does not explain the preference of S. sanguinea for sciaphilic habitats. High post-recruitment mortality due to various factors, especially competition with fast-growing algae, seems particularly relevant in determining the adult distributions observed.

The relationship between seasonal changes in temperature and the size of zooids within cheilostome bryozoans is explored by comparing zooid size and contemporaneous carbonate mineralogy within a single colony of a perennial species that grew in a highly seasonal environment. Previously published oxygen isotope profile data from two fronds of a large colony of Pentapora foliacea from the Irish Sea record the cyclical patterns related to seasonal changes in temperature experienced by the colony over 3 years of growth. Zooid size data gathered from the same points at which the oxygen isotope data were taken reveal that zooid size and contemporaneous [delta][sup.18]O values covary. These and previously published data show that zooid size profiling can be confidently used to easily estimate rates of growth and longevity of bryozoan colonies, and further illustrate the negative relationship between zooid size and ambient temperature. Some inconsistencies in timing between zooid size and [delta][sup.18]O data may provide insights into the mechanisms behind temperature mediated body size changes in poikilothermic animals.

The positive relationship between offspring size and offspring fitness is a fundamental assumption of life-history theory, but it has received relatively little attention in the marine environment. This is surprising given that substantial intraspecific variation in offspring size is common in marine organisms and there are clear links between larval experience and adult performance. The metamorphosis of most marine invertebrates does not represent a 'new beginning,' and larval experiences can have effects that carry over to juvenile survival and growth. We show that larval size can have equally important carryover effects in a colonial marine invertebrate. In the bryozoan Bugula neritina, the size of the non-feeding larvae has a prolonged effect on colony performance after metamorphosis. Colonies that came from larger larvae survived better, grew faster, and reproduced sooner or produced more embryos than colonies that came from smaller larvae. These effects crossed generations, with colonies from larger larvae themselves producing larger larvae. These effects were found in two populations (in Australia and in the United States) in contrasting habitats. Key words: bryozoan; Bugula neritina; carryover effect; maternal effect; reproductive success.

Ectoprocts, phoronids and brachiopods are often dealt with under the heading Tentaculata or Lophophorata, sometimes with entoprocts discussed in the same chapter, for example in Ruppert and Barnes (1994). The Lophophorata is purported to be held together by the presence of a 'lophophore,' a mesosomal tentacle crown with an upstream-collecting ciliary band. However, the mesosomal tentacle crown of pterobranchs has upstream-collecting ciliary bands with monociliate cells, similar to those of phoronids and brachiopods, although its ontogeny is not well documented. On the contrary, the ectoproct tentacle crown carries a ciliary sieving system with multiciliate cells and the body does not show archimery, neither during ontogeny nor during budding, so the tentacles cannot be characterized as mesosomal. The entoprocts have tentacles without coelomic canals and with a downstream-collecting ciliary system like that of trochophore larvae and adult rotifers and serpulid and sabellid annelids. Planktotrophic phoronid and brachiopod larvae develop tentacles at an early stage, but their ciliary system resembles those of echinoderm and enteropneust larvae. Ectoproct larvae are generally non-feeding, but the planktotrophic cyphonautes larvae of certain gymnolaemates have a ciliary band resembling that of the adult tentacles. The entoprocts have typical trochophore larvae and many feed with downstream-collecting ciliary bands. Phoronids and brachiopods are thus morphologicaily on the deuterostome line, probably as the sister group of the 'Neorenalia' or Deuterostomia sensu stricto. The entoprocts are clearly spiralians, although their more precise position has not been determined. The position of the ectoprocts is uncertain, but nothing in their morphology indicates deuterostome affinities. 'Lophophorata' is thus a polyphyletic assemblage and the word should disappear from the zoological vocabulary, justas 'Vermes' disappeared many years ago.

Marine bryozoans have a variety of behavioural reactions that are associated with different functions: feeding, cleaning, removal of filtered water, gamete release, avoidance reactions and, probably, sensation. Coordinated activities of polypides are regulated neurophysiologically, physiologically, structurally and, possibly, hormonally. Several group reactions are supposedly non-coordinated. Group autozooidal reactions and different types of colonial behaviour were observed and recorded for 17 bryozoan species and subspecies from the White and Barents Seas. Three local collective reactions (synchronised scanning, repeated particle transfer by circular water currents, and feeding and cleaning of the colony surface by 'chains' of inclined lophophores) are described for the first time. The formation of water outlets (chimneys) was observed in four species with encrusting colonies. A new type of chimney was discovered in large colonies of Tegella armifera, in which chimneys are formed by temporary retraction of 10-12 neighbouring polypides. The space thus formed is surrounded by equitentacled lophophores standing vertically. Chimneys associated with elevated areas on the colony surface (monticules) were found in two species. In contrast to all previously published speculations and observations, the monticules were often places of incurrent rather than excurrent flow, and water outlets were formed in depressions between monticules. In Schizomavella lineata, monticules change their function from incurrent to excurrent after polypide degeneration. Conditions for the origin of various types of water outlets are discussed.

Almost 2000 cheilostomatid-cheilostomatid (bryozoan) interactions were recorded from 110 rocks from intertidal and infralittoral zone locations at Kodiac Island in the Alaskan Boreal-Arctic. Intraspecific interactions were unusually rare; this may have resulted from inhibition of con-specific settlement by adult colonies. In one species, rank did vary as a function of depth. The proportion of determinate-species encounter-pairings (a pairing in which one competitor/species wins all encounters) and tied outcomes (whereby neither competitor/species wins or loses but are involved in a 'standoff' or mutual overgrowth) increased from the upper midlittoral to the lower infralittoral. The assemblage of bryozoans formed a clear hierarchy, with a score of 0.83 on Tanaka and Nandakumar's transitivity index. Overgrowth dominants did not monopolise the assemblage. The most abundant species were mid- or lower-ranked competitors. The identity of the competitive species had a major influence on the outcome of encounters. Zooidal height and colony growth morphology were important factors determining overall overgrowth rank. The greatest number of interaction types was recorded on medium-sized (surface area > 300 and < 600 [cm.sup.2]) rocks, and the overall diversity of intertidal species was very high compared with studies conducted elsewhere. The high interaction and species diversity recorded may both have resulted from intermediate levels of disturbance.

Allozymes and mitochondrial DNA sequencing show that the marine bryozoan Membranipora villosa is an induced phenotype of M. membranacea and not a distinct species. Researchers must use caution when attempting to identify species in phenotypically plastic organisms.

Structures that mimic the general shape of cheilostome avicularia occur within the Paleozoic fenestrate bryozoan genus Fenestrapora. These structures, here termed aviculomorphs, are isolated within laminar extrazooidal skeleton and are characterized by an elongate triangular outline that surrounds a shallow, concave pit. The acute tip of the triangular structure was elevated above the general level of the surrounding skeleton, as is the case for many avicularia. The aviculomorphs could not have functioned precisely as do avicularia, but like avicularia they are inferred to have had a thickened cuticular mandible that matched the skeletal base and to have been able to articulate the mandible open and closed along a fulcrum on the short side of the triangular skeletal outline.

Relative differences between environmentally controlled variation and genetically controlled variation are important when investigating morphologic variation in general, especially when establishing species concepts. The colonial nature of bryozoans provides a means for distinguishing between the two sources; variation can be partitioned into within-colony (microenvironmental) and amongcolony (environmental + genetic) components. For the Paleozoic order Cryptostomata, biologically and taxonomically significant morphologic characters are well defined and methods for recognizing morphotaxa are well established. The importance of within-colony variation to the morphometric treatment of fenestrate species was assessed after the discovery of a large specimen of Hemitrypa sp. Variation within the colony was compared to variation among and within two congeneric species. The distribution of study segments across the colony allowed assessment of variation both along the growth axis and laterally between segments of approximately equivalent generational age. Repeatability of methods was assessed using data measured independently from identical segments by three workers. Variation within the large colony is less than variation among congeneric species, indicating that genetic differences among species exceed variation resulting from combined phenotypic and genotypic sources within species. Neither astogenetic nor ontogenetic morphologic gradients are recognized. Variation between data collected from identical segments by pairs of workers falls within the range of variation for the entire colony. Thus, multiple workers can reproduce data to the finest level of meaningful resolution. Cryptostome morphospecies concepts are validated. The potential for partitioning genotypic versus environmental variation in reduced, multidimensional morphospace is reinforced. Studies of microevolution and speciation may be designed that account for these factors.

The seasonality of polypide cycling was studied for three species of erect bryozoans from Antarctica. These are the Isoseculiflustra rubefacta, Nematoflustra flagellata and Himantozoum antarcticum. Findings showed that polypide cycling in all three species was seasonal. New zooids formed at the growth margin and usually contained actively feeding polypides for approximately 9 mos before these polypides degenerated into brown bodies in the austral winter. Very few polypides were active when water-column food levels were least.

The bryostatins are a unique family of emerging cancer chemotherapeutic candidates isolated from marine bryozoa. Although the biochemical basis for their therapeutic activity is not known, these macrolactones exhibit high affinities for protein kinase C (PKC) isozymes, compete for the phorbol ester binding site on PKC, and stimulate kinase activity in vitro and in vivo. Unlike the phorbol esters, they are not first-stage tumor promoters. The design, computer modeling, NMR solution structure, PKC binding, and functional assays of a unique class of synthetic bryostatin analogs are described. These analogs (7b, 7c, and 8) retain the putative recognition domain of the bryostatins but are simplified through deletions and modifications in the C4-C14 spacer domain. Computer modeling of an analog prototype (7a) indicates that it exists preferentially in two distinct conformational classes, one in close agreement with the crystal structure of bryostatin 1. The solution structure of synthetic analog 7c was determined by NMR spectroscopy and found to be very similar to the previously reported structures of bryostatins 1 and 10. Analogs 7b, 7c, and 8 bound strongly to PKC isozymes with [K.sub.i] = 297, 3.4, and 8.3 nM, respectively. Control 7d, like the corresponding bryostatin derivative, exhibited weak PKC affinity, as did the derivative, 9, lacking the spacer domain. Like bryostatin, acetal 7c exhibited significant levels of in vitro growth inhibitory activity (1.8-170 ng/ml) against several human cancer cell lines, providing an important step toward the development of simplified, synthetically accessible analogs of the bryostatins.

The biology of the bryozoan Pentapora fascialis was studied in the northwestern Mediterranean. Several zoaria in two stations of 11 and 22 m at Tino Island were monitored over 15 months using underwater photography. An analysis of growth, colony size, shape and mortality was performed to examine the development of the clonal organisms. Results indicate that growth was highest during spring and that it was inversely proportional to colony size.

The calcareous skeletons of modern bryozoans are major contributors to sediments only outside the tropics, and many temperate limestones are dominated by bryozoans, often in conjunction with mollusks in the so-called 'bryomol' grain association. Can the presence of rock-forming abundances of bryozoans be used to recognize nontropical sediments in the geologic past? We have addressed this question by assembling a database of 176 Ordovician-Pleistocene bryozoan-rich deposits and plotting them on paleogeographical maps to obtain their latitudes of formation. The results reveal a striking difference between post-Paleozoic and Paleozoic latitudinal distributions. Whereas the great majority (94%) of post-Paleozoic bryozoan-rich deposits formed outside the tropics, Paleozoic bryozoan-rich deposits have a more variable latitudinal distribution, most (68%) having formed within the tropics. The presence of rock-forming abundances of bryozoans in Paleozoic sediments should not, therefore, be used to infer nontropical carbonate deposition. The change in latitudinal distribution between the Paleozoic and post-Paleozoic corresponds with a major taxonomic turnover in bryozoan faunas. Biotic interactions, especially with predators, may have led to the exclusion of sediment-producing bryozoans from the post-Paleozoic tropics. These evolutionary changes have had a more profound effect on carbonate platforms than has been previously appreciated.

An unusual, lichenoporid-like bryozoan colony from Mid-Silurian strata on Gotland is described as a new cystoporate, Inconobotopora lichenoporoides new genus and species; a poorly known form from the same area and approximate horizon is reclassified as Inconobotopora silurica (Hennig, 1906). Similarities in overall morphology, particularly flagged by the distinctive radial-disk construction, combine with geochronologic sequence to suggest the possibility of an evolutionary lineage from Ordovician Constellaria, through Silurian Inconobotopora, to Devonian Botryllopora, and perhaps even on to Cretaceous- Cenozoic-Recent Lichenopora (although this last extension is extremely difficult to demonstrate in the present state of knowledge).

The problem of how genotypes evolve a broad phenotypic range or extreme 'plasticity' has been of interest to biologists since Woltereck (1909) conducted the first norm-of-reaction experiments with genotypes of [...]

A thin limestone tongue in the upper part of the Murdock Mountain Formation of northeastern Nevada contains abundant bryozoans of earliest Wordian age. This bryozoan fauna is close to the Kungurian-Kazanian boundary in Russia. These bryozoans are younger than those found in the Kaibab Formation of southern Nevada and slightly older than those in the Gerster Limestone of northern Nevada. This limestone tongue, herein referred to as the Stenodiscus beds, lies below the Thamnosia beds described by Wardlaw in the Murdock Mountain section of the Leach Mountains. This bryozoan-rich limestone tongue serves as a marker unit for mapping the Murdock Formation in the Leach Mountains. Nine new species of bryozoans occur in the Stenodiscus beds of the Murdock Mountain Formation: Hinganella felderi, Neoeridotrypella schilti, Stenopora parvaexozona, Stenodiscus murdockensis, Dyscritella acanthostylia, Pseudobatostomella irregularis, Streblotrypa (Streblotrypa) elongata, Morozoviella praecurriensis, and Thamniscus erraticus, Hinganella felderi, Neoeridotrypella schilti, Dyscritella acanthostylia, and Streblotrypa (Streblotrypa) elongata are very similar to species described from Russia.

The fitness consequences of male gonad allocation was studied using Celleporella hyalina, a hermaphroditic colonial bryozoan species which houses its gonads in unisexual modules called zooids, as experimental model. The results provided evidences that sexual selection on male fertilization success may favor increased male gonad allocation in free-spawning marine invertebrates. It was also evident from the findings that sexual selection on male success in competition may be a major determining factor in the evolution of reproductive traits in marine species.

The fertilization biologies of nine gymnolaemate bryozoans in terms of the locations and oogenic stages of eggs at the time of sperm-egg fusion were compared. The data indicated that sperm fuse with primary oocytes in or near ovaries and that 83% to 100% of eggs fuse with sperm. In gymnolaemates, whose embryos develop in the water column, ovicell, introvert or embryo sac, egg activation is delayed until oocytes are spawned.

Waterborne algal compounds from the macroalgae species of Chlorophyta, Phaeophyta, Rhodophyta and Cyanophyta have varying effects on the larvae of the marine invertebrates of Hydroides elegans and Bugula neritina. Laboratory bioassays of the larvae from both types of invertebrates showed toxic effects due to compounds from Phaeophyta macroalgae. Algal compounds from Sargassum echinocarpum, S. polyphyllum and Sphacelaria tribuloides significantly inhibited the settlement of Bugula neritina larvae. The settlement of the invertebrate larvae was significantly enhanced by Padina australis.

There is a growing realization that events during one portion of an organism's life cycle can have both subtle and dramatic effects on other stages in the life history. Lethal and sublethal effects associated with the duration of larval swimming in marine invertebrates were examined for the bryozoan Bugula neritina. Larvae were kept swimming up to a maximum of 28 h at 20 [degrees] C by exposure to continuous bright fluorescent illumination. At 4-h intervals, samples of 20-40 larvae were removed from bright illumination and were exposed to seawater containing 10 mM excess KCl, an inducer of metamorphosis in this species. Over the first 12 h of larval swimming, an average of about 90% of the larvae initiated and completed metamorphosis; at 16 h, the percentage of larvae initiating and completing metamorphosis dropped significantly. By 28 h, about half of the larvae were initiating metamorphosis, whereas only one-fifth were completing metamorphosis. Larval swimming duration also significantly affected the duration of metamorphosis. By 30 h of larval swimming, individuals were taking about 25% longer to complete metamorphosis. Compared to ancestrulae that developed from larvae that were induced to metamorphose shortly after the onset of swimming, those that swam for greater than 8 h had significantly smaller lophophores. For example, by 28 h of larval swimming the ancestrular lophophore decreased in height, surface area, and volume by about 25%, 40% and 55%, respectively. This marked decrease in lophophore size may ultimately affect the ability of juveniles to sequester food, compete for space, and attain reproductive maturity. Thus, increasing the duration of larval swimming affects both metamorphosis and the development of postlarval structures, which may ultimately influence colony fitness.

Observed diversity of bryozoans within Devonian stages is not significantly different from range-through values for species because very few species have ranges longer than a single stage. Generic diversity differs significantly between observed stadial and stadial range-through values except for the diverse Givetian faunas. Among families, observed stadial and range-through comparisons differ significantly in the lower diversity Early and Late Devonian but are not significant in the taxonomically diverse Middle Devonian. The patterns of Devonian generic and familial diversity are apparently robust proxies for specific diversity. Givetian specific and generic extinctions, based on generated bootstrap distributions, are significantly higher than the other six Devonian stages even when modifications for different stage durations are considered. Based on present data, we conclude that a major change in Devonian diversity occurred between the Givetian and the Frasnian stages. Givetian specific and generic extinctions are not 'smeared' with respect to adjacent stages and should qualify as a mass extinction among bryozoans pending more accurate data on bryozoan ranges and more precision in radiometric dating of Devonian stadial boundaries. Devonian bryozoan familial extinctions are not numerous and do not exhibit a significant number of extinctions for any stage. The Givetian extinction, which for the time being ranks as the largest bryozoan extinction in the Phanerozoic, is a global event with a marked local effect in the Hamilton-Tully fauna of New York, Pennsylvania, and Ontario. Givetian specific originations are significantly higher than bootstrap distributions for both raw data and data modified for stadial durations. A Givetian generic high in originations for raw data is not significant when modified for stadial durations and only Eifelian familial originations are significantly higher than bootstrapped distributions.

A distinctive spiral unilaminate cyclostome bryozoan, recently discovered in the Eocene Castle Hayne Limestone Formation of eastern North Carolina, is described as Crisidmonea archimediformis new species. Colonies have a thickened spiral axis bearing systems of bifurcating branches. When worn and stripped of their branches, the resistant axes closely resemble the familiar screws of the Carboniferous to Permian fenestrate bryozoan genus Archimedes. However, the Eocene screws are shorter and become more loosely coiled with growth, corresponding to a helicospiral rather than a helical form. The paleoenvironment inhabited by C. archimediformis colonies is inferred to have been on the shallow (

This review of the goniocladiid genus Ramipora Toula is based on zoarial morphology. The diagnosis of Ramipora is emended and the type species R. hochstetteri Toula from the Upper Permian of Svalbard is redescribed. Anastomosing secondary branches forming a fenestrated meshwork discriminate Ramipora from other goniocladiids. Descriptions are based on new material collected from the type horizon (Kapp Starostin Formation, Akseloya) and elsewhere in the Svalbard Archipelago, and also on Toula's type specimen. Goniocladiella Nekhoroshev and Aetomacladia Bretnall are herein designated junior synonyms of Ramipora. Some species previously assigned to Ramipora are transferred to Ramiporidra.

Four species of Fenestrida and two species of Rhabdomesida occur in the Otter Formation (Visean) of the Little Belt Mountains, central Montana. Four species are new: Laxifenestella snyderi n. sp., Rectifenestella concava n. sp., Streblotrypa (Streblascopora) eastoni n. sp., and Nikiforovella beltensis n. sp. Several of these species are very similar to species described in Visean rocks of central Mongolia, northeast Russia, Kazakhstan, and Japan. Fabifenestella cf. F. vulgaris compares closely with F. vulgaris Gorjunova and Morozova from the Lower Carboniferous of northern Mongolia. Most of the bryozoans in the Otter Formation occur in the normal marine, subtidal carbonate mud and calcareous shale microfacies.

A study of the impact of bryozoan colonization on nitrogen acquisition by Macrocystis integrifolia and Agarum fimbriatum through a comparison of the uptake rates of ammonium and nitrate, and particulate nitrogen and carbon content of bryozoan-colonized- and clean kelp disks reveals that algae and bryozoans exhibit more complex interactions than epiphyte-substratum interactions. Colonization by Membranipora membranacea on Macrocystis integrifolia yields an inorganic nitrogen source during low seawater concentration periods, increasing productivity. The relationship between M. membranacea and M. integrifolia is at variance with that between Lichenopora novae-zelandiae and Agarum fimbriatum.

Biological Bulletin (Woods Hole) 181:261-268. @ [...]

Species-level taxonomy of fenestrate cryptostome bryozoans has been greatly advanced by a recent study of the fenestrate fauna of the Warsaw Formation (Osage-Meramecian) of the Mississippi Valley; subsequent quantitative analysis placed the earlier research on a sound statistical basis. Reproducibility of these results is tested here, and it is demonstrated that subsequent researchers can duplicate earlier data collection and results. The methodology is then extended in space and time to a second fenestrate faunule (Virgilian of east-central Kansas); morphs within two traditionally defined fenestrate species are successfully distinguished. Lithologic characteristics of the two Virgilian study units suggest differences in depositional environments between the horizons and therefore simple ecophenotypy and intraspecific variation cannot be dismissed. However, chamber dimensions, which provide the most sensitive characters for taxonomic discrimination, change in parallel for the two species, whereas exterior skeletal dimensions, which would presumably respond more readily to microenvironmental fluctuations, vary nonsystematically between populations. These results provide a starting point for the evaluation of morphologic change within fenestrates through stratigraphic and paleoenvironmental sequences. Cumulative data sets spanning long time intervals would allow evaluations of evolutionary histories among members of this important Paleozoic clade.

Until the late 1960's, most of Nicholson's types of Paleozoic bryozoans were no available for study. We present a set of coded characters of many of Nicholson' types, which should assist in bringing his species into conformity with current taxonomic standards so that his species can be consistently recognized and used in biostratigraphic, paleobiogeographic, and evolutionary studies. Cladistic an phenetic analyses of these species permit comparisons between inferred phylogenies of Nicholson specimens, adaptive morphospace, and treatise-based systematic relationships. Specimen-based cladistic and phenetic analyses of Nicholson's species both produce clusters that are congruent with existing family-level taxonomic assignments of species in the collection. However, cladistic analysis more fully retrieves the pattern of branching, or degree of relatedness, among higher taxa. Phenetic clusters represent adaptive peaks in morphospace for these specimens, but higher level 'phenons' are strongly affected by multiple evolution of the same character states.

Metabolic competence is discarded by the lecithotrophic larvae of Bugula neritina, a Cheilostome bryozoan, 12 to 24 hours after being released from the maternal zooid. The larvae exhibit active swimming behavior, which is revealed by their high rate of respiration. A 15. 24 milli Joule energy consumption is characteristic of all the larvae. Loss of metamorphic competence consumes 20% of the energy in the larvae.

Recently developed analytical procedures for meshwork fenestrate and pinnate bryozoans made it possible to recognize two Russian species in the Toroweap Formation of southern Nevada. This analysis separates zoarial and zooecial features and emphasizes the three-dimensional form and size of the zooecial chamber as well as accessory features. In this investigation, these analytical procedures are successful even when specimens are fragmented and embedded in a hard rock matrix. The bryozoans in the Toroweap Formation in this study were found to be more similar to Permian species of the Russian platform than to species described in earlier North American Permian studies. Five species of fenestrate bryozoans are present in the Toroweap Formation. Wjatkella permiana Morozova, 1970, and Polypora sargaensis Trizna, 1948, originally described in Russia, are recognized in the Toroweap. Three new species, Penniretepora oppositus n. sp., Septopora bilateralis n. sp., and Reteporidra anaphora n. sp., are present and, along with the Russian species, are described in this paper. The local range zones of the five species of fenestrates were identified in three measured sections. Penniretepora oppositus and Septopora bilateralis are present throughout the three sections; Reteporidra anaphora is present in the lower two-thirds of the three sections; Wjatkella permiana is present in the middle parts of the three sections; and Polypora sargaensis is present in the upper parts of the three sections. Concurrent range zones, based on ramose bryozoans, were previously identified in two of the three sections and, using the distribution of the fenestrates in these two sections, four of the five concurrent range zones were recognized in the third section.

Colonies of the runner-like bryozoans Corynotrypa delicatula (James) and C. inflata (Hall) are common encrusters of Middle and Upper Ordovician shells and hardgrounds, especially in Cincinnatian deposits. The simplicity of their zooids contrasts with complexities in the dynamics of colonial organization. Both species have uniserial branches that bifurcate at intervals and, in addition, give rise periodically to lateral ramifications. Although angles of bifurcation and lateral ramification each average about 80 degrees, bifurcations and lateral ramifications are fundamentally different modes of branch multiplication. In C. delicatula new lateral branches have conspicuous secondary zones of astogenetic change distinguished by elongation of successively budded zooids. Unlike bifurcations, the first zooids in lateral branches in Corynotrypa are not linked to the parent branch by a narrow basal canal, and each new lateral branch can be regarded as a distinct subcolonial unit. The ancestrula, described here for the first time in an Ordovician species of Corynotrypa, has a poorly differentiated protoecium and initiates a primary zone of astogenetic change. Colony growth in Corynotrypa was more plastic than in many other bryozoan runners. The systematics of C. delicatula and C. inflata are revised, and a lectotype is chosen for the former species.

Bimuropora dendroidea, previously assigned to other genera, is described from Tennessee and B. winchelli is reported from Nevada. The occurrence of B. winchelli in Nevada extends the geographic range of the Middle Ordovician trepostome genus Bimuropora in North America. These two species share many derived characteristics with the halloporids, including a similar growth pattern and fluted zooecial walls in the endozone. This strengthens the hypothesis that the bimuroporids are a sister group to the halloporids. Sonninopora, a monospecific genus, contains these same features, and because of the presence of acanthostyles it is removed from the family Halloporidae and assigned to the family Bimuroporidae.

A study was conducted to analyze the skeletal morphology of the species of cheilostome Stylopoma and its possible role in random genetic change and natural selection. Divergence was determined by computing for the range of possible divergences and phenotypic differences of the species. Analysis of the data revealed that selection is a method used in explaining the effects of random genetic change and species lineage.

The settlement of many common encrusting species are influenced by boundary-layer flows, and this may be due to larval behavior. The hydriod Tubular crocea settles in zones of strong shear stress and high turbulence, while Schizoporella unicornis, a bryozoan, prefer only regions of high shear stress. These responses are the causes of patchiness during colonization.

Reticulate Hornera reteramae (Bryozoa, order Cyclostomata) have been discovered as free-lying, lyre-shaped colonies in the Castle Hayne Limestone (Eocene) in North Carolina. These specimens represent a striking instance of homeomorphy in colony form with the Late Mississippian genera Lyropora and Lyroporella of the order Fenestrata. Bryozoans with reticulate growth habit most commonly develop upright colonies. Living representatives generally grow in quiet environments or microenvironments, and fossils are generally found in situ in quiet-water deposits. However, lyre-shaped Hornera reteramae occur in skeletal packstones inferred to have been deposited in a moderate-energy, shallow, open shelf environment near normal wave base. Upper Mississippian lyre-shaped colonies are preserved in skeletal packstones and grainstones in localized channels or on upper surfaces of low-angle cross-bedded sheets interpreted as high-energy, marine shoal deposits. Modification of the reticulate growth habit to low, peripherally weighted, free-lying structures apparently allowed invasion of higher energy sand bottoms, both in Mississippian and Eocene times.

The mechanism behind the self-fertilisation in Celleporella hyalina is investigated. Results show that autogamy is normally suppressed in hermaphroditic C. hyalina where outcrossing is possible, but self-fertilization is used as an emergency alternative. However, offsprings of self-fertilization experiences frequent abortion and absence of settlement due to reduced fitness as a result of inbreeding depression.

The influences of neighbors and flow regime on growth patterns and feeding rates of the bryozoan Electra pilosa were characterized in laboratory and field experiments. In laboratory studies, neighbors inhibited growth, while flow velocity exerted a negative effect on growth rates of isolated colonies but had no influence on growth rates of colonies with neighboring Electra upstream. There were no significant effects of neighborhood or flow on zooid dimensions. Field experiments, which only tested the influence of neighbors on growth, revealed a similar reduction in growth in the presence of neighbors. The growth responses displayed by Electra do not support predictions of adaptive strategy models: despite its noted range in colony morphology, Electra did not assume more runner-like shapes when growth conditions were poor. Rather, growth of Electra appeared to be a result of local astogenetic (colonial ontogenetic) rules.colonies that fed from similar flows to those they had experienced in the laboratory provide evidence backing the common assumption that patterns of feeding result in growth responses and so may be related to fitness in colonial animals. Evidence that growth patterns resulted from feeding rates suggests a central role for the acquisition of food in the dynamics of benthic assemblages of suspension feeders.

Evolutionary Significance of Morphospecies: A Test with Cheilostome Bryozoa MANY FOSSIL SPECIES APPEAR IN the record fully differentiated morphologically and persist for millions of years with little or no indication [...]