A late-surviving Triassic protomonaxonid sponge from the Paris Biota (Bear Lake County,Idaho, USA)

Protomonaxonid sponges are a major group of Cambrian and Ordovician fossils in exceptionally preserved (especially Burgess Shale-type) faunas, but are rare thereafter. Rare examples of apparent surviving lineages are known from the late Palaeozoic and Mesozoic, but by this time more derived groups of sponges have generally displaced them in at least shallow-water (shelf depth) ecosystems. The early Spathian (Early Triassic) Paris Biota includes abundant material of a new leptomitid protomonaxonid, Pseudoleptomitus advenus Botting nov. gen., nov. sp., distinguished by having an unbundled longitudinal skeleton and very weak transverse component. This is the first post-Ordovician leptomitid known, and indicates long-term survival of the group in unknown environments. Its occurrence near storm wave base is similar to the preferred environment of earlier examples of the family, suggesting either ecological rarity or taphonomic reasons for their ∼200-million-year absence from later Palaeozoic rocks.     

Fedomia mikhaili—A new spicule-bearing organism of sponge grade from the Vendian (Ediacaran) of the White Sea, Russia

The Vendian fossil locality on the Solza River is one of the most productive in the White Sea Region. The fossiliferous deposits belong to the Upper Vendian Verkhovka Formation correlated lithologically with strata dated at 558 ± 1 to 555.3 ± 0.3 Ma in adjacent regions. This locality is characterized by yielding more than 10 well-represented Ediacaran genera. Elongated imprints of Fedomia mikhaili, n. gen. et n. sp., are common at the Solza River fossil locality. The new taxon is characterized by its six- to eight-rayed star-shaped concave structures with diameters of 2–5 mm. The organism can be reconstructed with sacciform thin-walled body attached basally to the substrate. The star-shaped structures may be spicules that appear to be rather flexible than rigid. The new genus, Fedomia, shows some similarities to Eiffelia Walcott, 1920 from the Middle Cambrian of British Columbia, and thus is interpreted as an organism of sponge grade. The new taxon could represent an additional phylogenetic link between the Ediacaran and Cambrian worlds.     

A phylogenetic framework for the evolution of female polymorphism in anoles

Female pattern polymorphisms (FPP) are striking, poorly understood, and a major challenge to evolutionary theory. We examined the evolution of FPP in anoline lizards in a phylogenetic context. Accordingly, we used comparative analyses that traced the evolution of female pattern polymorphism over historical time, and overlaid the historical pattern on the biogeographical distribution of current species. Comparative analyses used a maximum likelihood approach with variable rates of trait evolution. We found that, among almost 180 well‐described species, 52 exhibited FPP and most of these occurred on the Central American mainland. Pagel's λ = 0.644 indicated not only a moderately strong phylogenetic signal in FPP among 162 species with sound estimates of phylogeny, but also independent evolution. Their common ancestor was not polymorphic (0.003% likelihood of FPP), and there were at least 28 gains or losses of FPP during phylogenetic history. The geographical distribution of FPP indicates that, in the Caribbean islands, it has been present for almost 20 million years, and that parallel evolution of FPP has taken place during that time, including independent evolution on Cuba, Hispaniola, and Puerto Rico. Evidence of parallel evolution of FPP in anoles was fairly strong. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 303–317.     

A skeleton‐less sponge of Caribbean mangroves: invasive or undescribed?

Recent surveys of sponges occurring on Caribbean mangrove roots demonstrated the presence of a skeleton‐less sponge of the genus Halisarca, very similar in its morphology to the temperate H. dujardinii. This study evaluated the possibility that the mangrove sponge was actually H. dujardinii that had been introduced into the Caribbean mangroves. Detailed histology revealed differences between the mangrove sponge and H. dujardinii in cuticle thickness, and in characteristics of the choanocytes, spherulous, and granular cells. Also, phylogenetic reconstruction and genetic distance estimates based on cytochrome oxidase I gene sequences clearly differentiated the mangrove Halisarca sp. from H. dujardinii. Therefore, we rejected the hypothesis of the invasion of H. dujardinii, recognizing instead the mangrove Halisarca sp. as a new species and naming it H. restingaensis sp. nov. Estimated levels of genetic variation in the ribosomal internal transcribed spacers indicated that populations of H. restingaensis sp. nov. are highly differentiated between Venezuela and Panama (F_st=0.71). This level of population differentiation is consistent with the short larval competence period that is common in members of the genus Halisarca.     

The Homoscleromorph sponge Oscarella lobularis,a promising sponge model in evolutionary and developmental biology

Sponges branch basally in the metazoan phylogenetic tree and are believed to be composed of four distinct lineages with still uncertain relationships. Indeed, some molecular studies propose that Homoscleromorpha may be a fourth Sponge lineage, distinct from Demospongiae in which they were traditionally classified. They harbour many features that distinguish them from other sponges and are more evocative of those of the eumetazoans. They are notably the only sponges to possess a basement membrane with collagen IV and specialized cell‐junctions, thus possessing true epithelia. Among Homoscleromorphs, we have chosen Oscarella lobularis as a model species. This common and easily accessible sponge is characterized by relatively simple histology and cell composition, absence of skeleton, and strongly pronounced epithelial structure. In this review, we explore the specific features that make O. lobularis a promising homoscleromorph sponge model for evolutionary and developmental researches.     

Ultrastructure and embryonic development of a syconoid calcareous sponge

Abstract. Recent molecular data suggest that the Porifera is paraphyletic (Calcarea+Silicea) and that the Calcarea is more closely related to the Metazoa than to other sponge groups, thereby implying that a sponge‐like animal gave rise to other metazoans. One ramification of these data is that calcareous sponges could provide clues as to what features are shared among this ancestral metazoan and higher animals. Recent studies describing detailed morphology in the Calcarea are lacking. We have used a combination of microscopy techniques to study the fine structure of Syconcoactum Urban 1905, a cosmopolitan calcareous sponge. The sponge has a distinct polarity, consisting of a single tube with an apically opening osculum. Finger‐like chambers, several hundred micrometers in length, form the sides of the tube. The inner and outer layers of the chamber wall are formed by epithelia characterized by apical–basal polarity and occluding junctions between cells. The outer layer—the pinacoderm—and atrial cavity are lined by plate‐like cells (pinacocytes), and the inner choanoderm is lined by a continuous sheet of choanocytes. Incurrent openings of the sponge are formed by porocytes, tubular cells that join the pinacoderm to the choanoderm. Between these two layers lies a collagenous mesohyl that houses sclerocytes, spicules, amoeboid cells, and a progression of embryonic stages. The morphology of choanocytes and porocytes is plastic. Ostia were closed in sponges that were vigorously shaken and in sponges left in still water for over 30 min. Choanocytes, and in particular collar microvilli, varied in size and shape, depending on their location in the choanocyte chamber. Although some of the odd shapes of choanocytes and their collars can be explained by the development of large embryos first beneath and later on top of the choanocytes, the presence of many fused collar microvilli on choanocytes may reflect peculiarities of the hydrodynamics in large syconoid choanocyte chambers. The unusual formation of a hollow blastula larva and its inversion through the choanocyte epithelium are suggestive of epithelial rather than mesenchymal cell movements. These details illustrate that calcareous sponges have characteristics that allow comparison with other metazoans—one of the reasons they have long been the focus of studies of evolution and development.     

Behavior and development of larvae in the sponge Haliclona amboinensis

Sponges play important roles in marine ecosystems by contributing to habitat complexity and benthopelagic coupling of nutrients. Yet, the reproduction and settlement behaviors of diverse sponge species are not well understood. Here, we examined the brooding demosponge Haliclona amboinensis, which is common on shallow reefs in Bolinao, northwestern Philippines. Gravid sponges were found between the months of May and August, coinciding with warmer sea surface temperature. Sponges released parenchymella larvae from brood chambers in the mid‐morning, suggesting that light and temperature may serve as cues to initiate hatching. Larvae immediately swam toward the surface upon emergence and migrated to the bottom of the tanks 1–2 hr after release. The presence of light and crustose coralline algae induced high larval settlement. Metamorphosis proceeded rapidly in vitro, with larval cells spreading laterally on the substrate. The osculum was first visible at 3 days after settlement. The short pelagic duration of larvae in H. amboinensis promotes local recruitment and may be important for the maintenance of sponge populations in the face of disturbances.     

Reevaluating sponge diversity and distribution in the Mediterranean Sea

The aim of this paper was (1) to update sponge diversity and distribution in the Mediterranean and (2) to re-examine faunal relationships among the Mediterranean areas on the basis of their sponge fauna. The Mediterranean demosponge faunal list was updated to 629 species by taking into consideration recent data from previously poorly studied areas. The species lists of 14 Mediterranean areas were compared on the basis of their sponge species richness, species composition, and taxonomic relatedness of species using multivariate analyses and diversity measures, such as PD, Delta+, and Lambda+. The 14 Mediterranean areas examined for their diversity and affinities were assembled into four major zoogeographic groups: the northwestern, northeastern, the central zone, and southeastern areas. Richest in species numbers were the areas belonging to the two northern groups. The species richness comparisons and similarity analyses performed at the generic level showed that it can be safely used as a surrogate for sponge species diversity in the Mediterranean. The results of this study showed that the simple traditional division of the Mediterranean Sea into a western, central, and eastern basin cannot reliably describe the distribution of sponges in the area. Thus, the W to E faunal decline previously presented for several faunal groups shifts to a general NNW-SSE pattern when one examines separately the northern and the southern parts of the traditional basins. This gradient seems to be in agreement with differences in key environmental variables, such as latitude, salinity, temperature, and water circulation, besides the typically examined distance from Gibraltar. Handling editor: T. P. Crowe     

A likelihood framework for inferring the evolution of geographic range on phylogenetic trees

Abstract At a time when historical biogeography appears to be again expanding its scope after a period of focusing primarily on discerning area relationships using cladograms, new inference methods are needed to bring more kinds of data to bear on questions about the geographic history of lineages. Here we describe a likelihood framework for inferring the evolution of geographic range on phylogenies that models lineage dispersal and local extinction in a set of discrete areas as stochastic events in continuous time. Unlike existing methods for estimating ancestral areas, such as dispersal‐vicariance analysis, this approach incorporates information on the timing of both lineage divergences and the availability of connections between areas (dispersal routes). Monte Carlo methods are used to estimate branch‐specific transition probabilities for geographic ranges, enabling the likelihood of the data (observed species distributions) to be evaluated for a given phylogeny and parameterized paleogeographic model. We demonstrate how the method can be used to address two biogeographic questions: What were the ancestral geographic ranges on a phylogenetic tree? How were those ancestral ranges affected by speciation and inherited by the daughter lineages at cladogenesis events? For illustration we use hypothetical examples and an analysis of a Northern Hemisphere plant clade (Cercis), comparing and contrasting inferences to those obtained from dispersal‐vicariance analysis. Although the particular model we implement is somewhat simplistic, the framework itself is flexible and could readily be modified to incorporate additional sources of information and also be extended to address other aspects of historical biogeography.     

Coastal sponge communities of the West Indian Ocean: morphological richness and diversity

Sponges are a reasonably ubiquitous, abundant and highly morphologically plastic taxon. They are very unusual in showing considerable morphological plasticity, not only within higher taxa but within species and at macro and micro scales. In this study we determined the prevalence of sponge morphologies at four coastal study regions in the west Indian Ocean. We show that tropical and subtropical assemblages (in the present study) can be separated on the basis of morphological composition alone (by > 4% arborescent forms or presence of palmate forms in the former). Inter‐tidal sponge assemblages can also be separated from those in the subtidal to a high degree of certainty, also on prevalence of morphologies (absence of tubular or branching forms in the former). The species diversity of many sponge assemblages has been quantified in various environments but, typically, only by specialists. Rarely have equivalent measures been made of morphological diversity. Values of morphological diversity (Shannon H′) were similar, though more variable, to those measured in temperate waters. Substratum nature had a major influence on morphological diversity and evenness, in contrast to geography and bathymetry. As coral reefs were the most diverse and caves and boulders the least, we suggest that substratum heterogeneity and water‐flow complexity are probably the chief determinant of sponge assemblage morphological diversity.     

Ubiquitins (polyubiquitin and ubiquitin extension protein) in marine sponges: cDNA sequence and phylogenetic analysis

The complete nucleotide sequences of two Suberites domuncula cDNAs and one Sycon raphanus cDNA, all encoding ubiquitin, have been determined. One cDNA from S. domuncula codes for polyubiquitin with four tandemly repeated monomeric units and the second cDNA encodes ubiquitin fused to a ribosomal protein of 78 amino acids (aa). S. domuncula possesses at least one additional polyubiquitin gene, from which the last two monomers were also sequenced. All analysed genes from S. domuncula encode identical ubiquitin proteins, with only one aa difference (Ala 19) to the human/higher animals ubiquitin (Pro 19). Ubiquitin in S. domuncula is identical with the ubiquitin found in another Demospongia, Geodia cydonium. The cDNA from S. raphanus encodes polyubiquitin with seven tandemly repeated units. All these gene monomers code for the same ubiquitin, which differs from the human/higher animals ubiquitin only at position 24 (Asp in Sycon, Glu in others). However, ubiquitin from S. raphanus (Calcarea) shows two aa differences (positions 19 and 24), when compared with the ubiquitin sequences from the two Demospongiae. In a phylogenetic tree constructed by multiple sequence alignment of all sponge ubiquitin gene monomers so far identified, all monomers from the same species cluster together, with the clear exception of the monomer from S. domuncula ribosomal protein fusion gene. This monomer branches off first from the tree and forms a separate line; this gives evidence for a very ancient split of ubiquitin-ribosomal-protein fusion genes from polyubiquitin encoding genes and their long separate coexistence in eukaryotes. The ubiquitin extension protein from S. domuncula is 78 aa long, displays all characteristics of 76–81 aa long ribosomal fusion proteins and shows 78% identity in the first 73 aa with the human S27a protein. However, its C-terminal sequence: 69-GLTYVYKKSD-78 is more similar to the plant consensus (69-GLTYVYQ/NK-76), than to the higher animal consensus (69-CLTYCFNK-76). This protein isolated from a sponge, belonging to the phylogenetically oldest multicellular animals, the Porifera, branches off first from the phylogenetic tree of metazoan ubiquitin extension proteins of the small ribosomal subunits.     

Svenzea zeai, a Caribbean reef sponge with a giant larva, and Scopalina ruetzleri: a comparative fine-structural approach to classification (Demospongiae, Halichondrida, Dictyonellidae)

Abstract. Svenzea zeai , abundant on many deep Caribbean fore-reef habitats but of uncertain systematic position within the Demospongiae, is closely examined histologically and cytologically for evidence of its phylogenetic relationship beyond the traditional analysis of gross morphology and skeletal structure. We document that S. zeai is a bacteriosponge containing substantial quantities of unicellular photosynthetic and autotrophic microbes; that the most abundant cell type is an unusual cell with refractile granules that only few species share and whose composition and function are still enigmatic; and that it produces the largest—by a factor of 3—embryos and larvae recorded in the phylum Porifera. A combination of characters such as the granular cells, ciliary pattern, and aspects of larval shape and behavior are comparable with those of Scopalina ruetzleri , family Dictyonellidae, a prominent member of the Caribbean mangrove community. These results support our earlier decision to establish Svenzea as a new genus in Dictyonellidae to accommodate its unprecedented skeletal structure, styles in isodictyal reticulation.     

Locomotion and contraction in an asconoid calcareous sponge

Various large‐scale behaviors (e.g., locomotion, shape changes, contractions) have been documented numerous times in intact sponges of the class Demospongiae. However, little is known about such motile events in calcareous sponges (Class Calcarea). Here, we report on whole‐sponge behaviors of the calcareous asconoid sponge Leucosolenia botryoides, as revealed by time‐lapse videos. These behaviors included locomotion and contraction. Locomotion in these sponges appeared as an outward movement (25–130 μm h^?1) of the asconoid tubes away from the sponge's center; such translocations were always accompanied by extensive movements of protruding spicules, which appear to act as anchoring hooks for the sponge's translocations. This is the first report of whole‐sponge locomotion in the Calcarea. Contractile waves also were propagated in these sponges at speeds of 50–150 μm h^?1, and they involved systemic contraction, then re‐extension of the asconoid tubes. The observations suggest that, like the more complex demosponges, these simple calcareous sponges are capable of adaptive whole‐animal behaviors (changes in flow, shape, and location), which occur in response to environmental stimuli such as crawling intruders.     

A probable hyalonematid sponge (Hexactinellida: Amphidiscophora) from the Middle Ordovician of the Builth Inlier,Wales

Modern hexactinellid sponges are diverse, but almost exclusively deep-marine organisms with a very intermittent fossil record. Aside from the fused skeletons of hexactinosan lineages (which are also exceptionally rare in Palaeozoic sediments), identifying other families is challenging due to the microscopic nature of many diagnostic characters, and the need for exceptional preservation in a deep-water palaeoenvironment. Among the more distinctive living families is the Hyalonematidae, which have several preservable diagnostic features. A new sponge (Nectocollare zakdouli n. gen. n. sp.) from the Middle Ordovician Castle Bank fauna of Wales, UK, shows several of these characters, including pinular pentactine dermalia, unbundled choanosomal diactins, and a reticulate marginal rim at the apex. No root tuft is preserved, but these are often detached from fossil sponges. Although there remains some uncertainty over the assignment to Hyalonematidae, this sponge represents the only probable example from the Palaeozoic. Even in the absence of diagnostic microscleres, it likely represents a derived, crown-group hexactinellid, and further confirms the diversification of the class during the earliest Palaeozoic.     

Asexual reproduction and anterior regeneration under high and low temperatures in the sponge associate Polydora colonia (Polychaeta: Spionidae)

Regeneration in polychaetes is an important process because of its role in recovery after injury and in asexual reproduction via architomy. This study examined architomy and regeneration in the spionid worm, Polydora colonia (Moore 1907) a symbiont of sponges. Based on collections of P. colonia from Long Island, New York, prevalence of architomy was 24% (188 out of 780 worms) with the highest prevalence recorded during the summer and early fall and the lowest prevalence during late fall and winter. Morphogenesis during regeneration of P. colonia was studied with light and scanning electron microscopy at two different temperatures. Worms regenerated faster under high temperatures (24°C), whereas it took more than twice as long to regenerate under low temperatures (14°C). Morphogenesis during anterior regeneration included the formation of a blastema from which a maximum of eight anterior segments regenerated. At high temperatures, palp buds and initial segments were observed to form by day 2 and 1–2 major spines were observed in the fifth segment by day 8. This is the first report of asexual reproduction in the field for the genus Polydora and the results indicate that temperature plays a role in regeneration.     

Ediacaran macroalgal holdfasts and their evolution: a case study from China

A macroalgal holdfast (root-like structure) anchored or grown into sediments is a key trait of metaphytes and eukaryotic algae. Various patterns and taphonomic variants of congeneric holdfasts are preserved on the bedding planes of black shales of the Ediacaran Wenghui biota in South China. The macroalgal holdfast, which commonly consists of a rhizome, rhizoid and pith (perhaps mechanical tissue), can be morphologically classified into ten types within four groups of rhizomes: bare rhizome holdfasts (Grypania, Tongrenphyton and Sectoralga-type holdfasts), canopy rhizome holdfasts (Gemmaphyton, Gesinella, Discusphyton and Baculiphyca-type holdfasts), pithy rhizome holdfasts (Zhongbaodaophyton and pithy-cone-type holdfasts) and differentiated rhizome holdfasts (Wenghuiphyton-type holdfasts). Analysis of the Precambrian macroalgal record indicates that rhizomes played a more important role in the evolution of macroalgal holdfast than rhizoids. The following evolutionary stages of development of macroalgal holdfasts are proposed: (1) growth of the basal thallus into sediments (Grypania-type holdfast); (2) development of a primitive (indistinct) rhizome from the base of a stipe or thallus (Tongrenphyton-type and Sectoralga-type holdfasts); (3) growth of a distinct rhizome with rhizoid (Gemmaphyton-type, Gesinella-type and Discusphyton-type holdfasts); (4) development of a pith in the stipe (Baculiphyca-type holdfast); (5) pith extension into the rhizome (Zhongbaodaophyton-type and pithy-cone-type holdfasts); and (6) rhizome differentiation and development of a complex holdfast system (Wenghuiphyton-type holdfast).     

A multigene framework for polychaete phylogenetic studies

Producing a robust phylogenetic reconstruction for Polychaeta using either morphological or molecular data sets has proven very difficult. There remain many conflicts between morphological analyses and hypotheses based on DNA data, the latter principally derived from 18S rRNA sequences. For the present study a data set covering a broad range of polychaete diversity was assembled, including 38 new sequences from 21 species. Besides available 18S rRNA data, five additional gene segments were examined: the D1 and D9-10 expansion regions of 28S rRNA, histone H3, snU2 RNA and cytochrome c oxidase subunit I. Maximum parsimony, maximum likelihood and Bayesian analyses were conducted.Annelida and Mollusca were reciprocally monophyletic in maximum likelihood analyses, but Polychaeta included a cephalopod in maximum parsimony analyses, and a patellogastropod in Bayesian analyses. When rooted on the Mollusca, optimal topologies from maximum likelihood analyses showed a recognisable basal group of taxa, including Oweniidae, Chaetopteridae and Amphinomidae. The six studied phyllodocidan families plus Orbiniidae (as the sister group of the scale-worms) formed the next most basal group. All analyses support the inclusion of Echiura, Clitellata and Siboglinidae within polychaetes. Bayesian analyses show Echiura as the sister group of Capitellidae, in agreement with previous 18S rRNA results, In contrast, Echiura formed the sister group to Trichobranchidae in maximum likelihood and maximum parsimony analyses.Supra-familial groupings consistently recovered within Polychaeta in the analyses are: (i) Terebellida without Ampharetidae; (ii) Scolecida (excepting Orbiniidae); (iii) Eunicidae, Lumbrineridae and Clitellata; and (iv) “Cirratuliformia” (including Sternaspidae) plus Sabellidae, Serpulidae and Spionidae.     

A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution

We sequenced 2800 bp of mitochondrial DNA from each of 33 species and 2 subspecies (35 taxa) of terns (Sternini), and employed Bayesian methods to derive a phylogeny with good branch support based on posterior probabilities. The resulting tree confirmed many of the generally accepted taxonomic groups, and led us to suggest a revision of the terns that recognizes 12 genera, 11 of which correspond to a distinct clade on the tree or a highly divergent species (1 genus was not represented in the phylogeny). As an example of how the molecular phylogeny reflects similarities in morphology and behavior among the terns, we used the phylogeny to examine the evolution of the breeding (alternate) head plumage patterns among the terns to test the hypothesis that this character is phylogenetically informative. The three basic types of head plumage (white crown, black cap, and black cap with a white blaze on the forehead) were highly conserved within clades, with notable exceptions in two white-crowned species that evolved independently among the black-capped terns. Based on the appearance of the close relatives of these exceptional species, their white crowns appear to be due to the retention of either winter (basic) plumage characteristics or perhaps juvenile characteristics when the birds molt into their breeding plumage. Examination of the evolutionary history of head plumage indicated that the white-crowned species such as the noddies (Anous) and the white tern (Gygis alba) are probably most representative of ancestral terns.