Jarosław Stolarski

A comprehensive phylogenetic analysis of the Scleractinia (Cnidaria, Anthozoa) based on mitochondrial CO1 sequence data

Background Classical morphological taxonomy places the approximately 1400 recognized species of Scleractinia (hard corals) into 27 families, but many aspects of coral evolution remain unclear despite the application of molecular phylogenetic methods. In part, this may be a consequence of such studies focusing on the reef-building (shallow water and zooxanthellate) Scleractinia, and largely ignoring the large number of deep-sea species. To better understand broad patterns of coral evolution, we generated molecular data for a broad and representative range of deep sea scleractinians collected off New Caledonia and Australia during the last decade, and conducted the most comprehensive molecular phylogenetic analysis to date of the order Scleractinia. Methodology Partial (595 bp) sequences of the mitochondrial cytochrome oxidase subunit 1 (CO1) gene were determined for 65 deep-sea (azooxanthellate) scleractinians and 11 shallow-water species. These new data were aligned with 158 published sequences, generating a 234 taxon dataset representing 25 of the 27 currently recognized scleractinian families. Principal Findings/Conclusions There was a striking discrepancy between the taxonomic validity of coral families consisting predominantly of deep-sea or shallow-water species. Most families composed predominantly of deep-sea azooxanthellate species were monophyletic in both maximum likelihood and Bayesian analyses but, by contrast (and consistent with previous studies), most families composed predominantly of shallow-water zooxanthellate taxa were polyphyletic, although Acroporidae, Poritidae, Pocilloporidae, and Fungiidae were exceptions to this general pattern. One factor contributing to this inconsistency may be the greater environmental stability of deep-sea environments, effectively removing taxonomic “noise” contributed by phenotypic plasticity. Our phylogenetic analyses imply that the most basal extant scleractinians are azooxanthellate solitary corals from deep-water, their divergence predating that of the robust and complex corals. Deep-sea corals are likely to be critical to understanding anthozoan evolution and the origins of the Scleractinia.

Corallite wall and septal microstructure in scleractinian reef corals: Comparison of molecular clades within the family Faviidae

Recent molecular phylogenies conflict with traditional scleractinian classification at ranks ranging from suborder to genus, challenging morphologists to discover new characters that better agree with molecular data. Such characters are essential for including fossils in analyses and tracing evolutionary patterns through geologic time. We examine the skeletal morphology of 36 species belonging to the traditional families Faviidae, Merulinidae, Pectiniidae, and Trachyphylliidae (3 Atlantic, 14 Indo‐Pacific, 2 cosmopolitan genera) at the macromorphological, micromorphological, and microstructural levels. Molecular analyses indicate that the families are not monophyletic groups, but consist of six family‐level clades, four of which are examined [clade XV = Diploastrea heliopora; clade XVI = Montastraea cavernosa; clade XVII (“Pacific faviids”) = Pacific faviids (part) + merulinids (part) + pectiniids (part) + M. annularis complex; clade XXI (“Atlantic faviids”) = Atlantic faviids (part) + Atlantic mussids].

Skeletal growth, ultrastructure and composition of the azooxanthellate scleractinian coral Balanophyllia regia

The biomineralization process and skeletal growth dynamics of azooxanthellate corals are poorly known. Here, the growth rate of the shallow-water dendrophyllid scleractinian coral Balanophyllia regia was evaluated with calcein-labeling experiments that showed higher lateral than vertical extension. The structure, mineralogy and trace element composition of the skeleton were characterized at high spatial resolution. The epitheca and basal floor had the same ultrastructural organization as septa, indicating a common biological control over their formation. In all of these aragonitic skeletal structures, two main ultrastructural components were present: “centers of calcification” (COC) also called rapid accretion deposits (RAD) and “fibers” (thickening deposits, TD). Heterogeneity in the trace element composition, i.e., the Sr/Ca and Mg/Ca ratios, was correlated with the ultrastructural organization: magnesium was enriched by a factor three in the rapid accretion deposits compared with the thickening deposits. At the interface with the skeleton, the skeletogenic tissue (calicoblastic epithelium) was characterized by heterogeneity of cell types, with chromophile cells distributed in clusters regularly spaced between calicoblasts. Cytoplasmic extensions at the apical surface of the calicoblastic epithelium created a three-dimensional organization that could be related to the skeletal surface microarchitecture. Combined measurements of growth rate and skeletal ultrastructural increments suggest that azooxanthellate shallow-water corals produce well-defined daily growth steps.

Systematics of the coral genus Craterastrea (Cnidaria, Anthozoa, Scleractinia) and description of a new family through combined morphological and molecular analyses

The monotypic genus Craterastrea was assigned to the family Siderastreidae owing to the similarity of its septal micromorphology to that of Coscinaraea. Subsequently, it was synonymized with Leptoseris, family Agariciidae, based on corallum macromorphology. Since then, it has remained poorly studied and has been known only from a small number of specimens from relatively deep reef environments in the Red Sea and the Chagos archipelago, northern Indian Ocean. Access to museum collections enabled examination of type material and the recovery of coral skeletons from the Seychelles, Madagascar, and Mayotte, southern Indian Ocean. A recent survey in Mayotte allowed the in situ imaging of Craterastrea in shallow and turbid reef environments and sampling for molecular analyses. The molecular analyses were in agreement with the examination of micromorphology and microstructure of skeletons by revealing that Craterastrea levis, the only species in the genus, differs much from Leptoseris foliosa, with which it was synonymized. Moreover, Craterastrea is closely related to Coscinaraea, Horastrea and Anomastraea. However, these genera, currently ascribed to the Siderastreidae, are genetically distant to Siderastrea, the familys type genus, and Pseudosiderastrea. Hence, we restore the genus Craterastrea, describe the new family Coscinaraeidae due to its deep evolutionary divergence from the Siderastreidae, and provide revised diagnoses of the four genera in the family. The description of the new family Coscinaraeidae is a further step in the challenging but ongoing process of revision of the taxonomy of scleractinian corals as a result of the molecular systematics revolution.

Strontium-86 labeling experiments show spatially heterogeneous skeletal formation in the scleractinian coral Porites porites

abundances of 86 Sr. The distribution of 86 Sr in the skeleton was imaged with the NanoSIMS ion microprobe with a spatial resolution of 200 nm and combined with images of the skeletal ultra-structure. Importantly, the distribution of the 86 Sr label in the P. porites skeleton was found to be strongly heterogeneous. This constrains the physical dimensions of the hypothetical Extracellular Calcifying Fluid (ECF) reservoir at the surface of the growing skeleton, which is implicit in most geochemical models for coral biomineralization. These new experimental capabilities allow for a much more detailed view of the growth dynamics for a wide range of marine organisms that

Nanotextures of aragonite in stromatolites from the quasi-marine Satonda crater lake, Indonesia

Abstract Stromatolites have been extensively used as indicators of ancient life on Earth. Although much work has been done on modern stromatolites, the extent to which biological processes control their structure, and the respective contributions of biological and abiotic processes in their formation are, however, still poorly constrained. A better description of the mineralogical textures of these formations at the submicrometre scale may help improve our understanding of how carbonates nucleate and grow in stromatolites. Here, we used a combination of microscopy and microspectroscopy techniques to study the chemical composition and the texture of aragonite in lacustrine stromatolites from the alkaline crator lake in Satonda, Indonesia. Several textural features are described, including morphological variations of aragonite from nanosized grains to micrometre-sized fibres, the presence of striations in the aragonite laminae showing a striking similarity with growth bands in corals, and clusters of small aragonite crystals sharing a common crystallographic orientation. These nanotextural features are compared with those observed in scleractinian corals, and possible processes involved in their formation are discussed.

Photopolymerized polypyrrole microvessels.

We report on the preparation of water-filled polymer microvessels through the photopolymerization of pyrrole in a water/chloroform emulsion. The resulting structures were characterized by complementary spectroscopic and microscopic techniques, including Raman spectroscopy, XPS, SEM, and TEM. The encapsulation of fluorescent, magnetic, and ionic species within the microvessels has been demonstrated. Confocal microscopy and fluorescence anisotropy measurements revealed that the encapsulated chromophore (Rhodamine 6G) resides within voids in the capsules; however, strong interaction of the dye with polypyrrole results in a measurable decrease in its rotational dynamics. Microvessels loaded with ferrofluid exhibit magnetic properties, and their structures can be directed with an external magnetic field. TEM measurements allowed imaging of individual nanoparticles entrapped within the vessels. The application of Cu(2+)-loaded microvessels as a transducer layer in all-solid-state ion-selective electrodes was also demonstrated.

Origin and phylogeny of Guyniidae (Scleractinia) in the light of microstructural data

The set of skeletal characters of the Recent azooxanthellate coral Guynia annulata Duncan, 1872 is unique among extant scleractinians and encompasses: (a) undifferentiated septal calcification centers (in most extant scleractinians calcification centers are clearly separated); (b) completely smooth septal faces (septa of almost all extant scleractinians bear granular ornamentation); (c) deeply recessed septa in respect to the epithecal rim in the adult coralla (in adults of the majority of extant scleractinians the relationships between septa and wall are the reverse); and (d) an aseptal part of the initial ontogenetic stage, just above the basal plate (almost all known scleractinians have a septate initial coralla). Skeletal features of five other extant traditional guyniids are typical of other caryophylliines (and of Scleractinia). However, the wall types present in different species of traditional guyniids exceed limits traditionally attributed to one caryophylliine family: i.e., Stenocyathus and Truncatoguynia have a marginothecal wall like the Flabellidae, whereas Schizocyathus and Temnotrochus usually have an entirely epithecal wall, as in Gardineriidae (Volzeioidea). Moreover, Pourtalocyathus and Schizocyathus show intraspecific variation in distribution of septal calcification centers (separated vs. non-separated) and in wall types (epithecal vs. consisting of large spherulite-like bodies). These major differences in skeletal architecture form the basis for a new, threefold taxonomical subdivision of the traditional guyniids: (1) Guyniidae Hickson, 1910, containing only monospecific Guynia with an epithecal wall, and septa with non-separated calcification centers; (2) Schizocyathidae fam.n., groups Microsmilia Schizocyathus, Pourtalocyathus, Temnotrochus, which have an epithecal wall and septa with usually well-separated calcification centers; and (3) Stenocyathidae fam.n. with Stenocyathus and Truncatoguynia which have a marginothecal wall and septa with well-separated calcification centers. Despite differences in the basic architecture of the skeleton, all taxa attributed to these families have ‘thecal pores’ formed by selective dissolution of the skeleton. I propose two hypotheses for evolutionary relationships among Guyniidae, Schizocyathidae, and Stenocyathidae: (1) Hypothesis A: the three families are not phylogenetically related and ‘pores’ originated independently in different scleractinian lineages: e.g., Guyniidae may represent distant zardinophyllid or gigantostyliid descendants, Schizocyathidae may be a volzeioid offshoot, whereas Stenocyathidae may be a flabellid descendant; (2) Hypothesis B: the three families are phylogenetically related and ‘thecal pores’ are synapomorphic for the clade (superfamily Guynioidea). Additional approaches, such as anatomical observations, molecular studies on guyniid DNA sequences, and in-depth studies on scleractinian biomineralization will be necessary to test these hypotheses.

A phylogeny reconstruction of the Dendrophylliidae (Cnidaria, Scleractinia) based on molecular and micromorphological criteria, and its ecological implications

Recent molecular phylogenetic studies have shown that most traditional families of zooxanthellate shallow‐water scleractinians are polyphyletic, whereas most families mainly composed of deep‐sea and azooxanthellate species are monophyletic. In this context, the family Dendrophylliidae (Cnidaria, Scleractinia) has unique features. It shows a remarkable variation of morphological and ecological traits by including species that are either colonial or solitary, zooxanthellate or azooxanthellate, and inhabiting shallow or deep water. Despite this morphological heterogeneity, recent molecular works have confirmed that this family is monophyletic. Nevertheless, what so far is known about the evolutionary relationships within this family, is predominantly based on skeleton macromorphology, while most of its species have remained unstudied from a molecular point of view. Therefore, we analysed 11 dendrophylliid genera, four of which were investigated for the first time, and 30 species at molecular, micromorphological and microstructural levels. We present a robust molecular phylogeny reconstruction based on two mitochondrial markers (COI and the intergenic spacer between COI and 16S) and one nuclear (rDNA), which is used as basis to compare micromorphogical and microstructural character states within the family. The monophyly of the Dendrophylliidae is well supported by molecular data and also by the presence of rapid accretion deposits, which are ca. 5 μm in diameter and arranged in irregular clusters, and fibres that thicken the skeleton organized in small patches of a few micrometres in diameter. However, all genera represented by at least two species are not monophyletic, Tubastraea excluded. They were defined by traditional macromorphological characters that appear affected by convergence, homoplasy and intraspecific variation. Micromorphogical and microstructural analyses do not support the distinction of clades, with the exception of the organization of thickening deposits for the Tubastraea clade.

The first modern solitary Agariciidae (Anthozoa, Scleractinia) revealed by molecular and microstructural analysis

Abstract. Dactylotrochus cervicornis (= Tridacophyllia cervicornis Moseley, 1881), which occurs in Indo-Pacific waters between 73 and 852 m, was originally described as an astraeid but was later transferred to the Caryophylliidae. Assumed to be solitary, this species has no stolons and only one elongated fossa, and is unique among azooxanthellate scleractinians in often displaying extremely long thecal extensions that are septate and digitiform. Based on both molecular phylogenetic analyses (partial mitochondrial CO1 and 16S rDNA, and partial nuclear 28S rDNA) and morphological characteristics, we propose the transfer of D. cervicornis from the Caryophylliidae to the Agariciidae, making it the first extant representative of the latter family that is solitary and from deep water (azooxanthellate). The basal position of D. cervicornis within the agariciids implied by our analyses strengthens the case for inclusion of fossil species that were solitary, such as Trochoseris, in this family and suggests that the ancestor of this scleractinian family, extant members of which are predominantly colonial and zooxanthellate, may have been solitary and azooxanthellate.