Microstructural characteristics of the stony coral genus Acropora useful to coral reef paleoecology and modern conservation

Identification of fossil corals is often limited due to poor preservation of external skeleton morphology, especially in the genus Acropora which is widespread across the Indo‐Pacific. Based on skeleton characteristics from thin section, we here develop a link between the internal skeleton structure and external morphology. Ten characteristics were summarized to distinguish Acropora and five related genera, including the type and differentiation of corallites, the skeleton nature of corallites (septa, columellae, dissepiments, wall), and calcification centers within septa. Acropora is distinctive for its dimorphic corallites: axial and radial. Isopora is similar to Acropora but possess more than a single axial corallites. Montipora and Astreopora (family Acroporidae) have monomorphic corallites and a synapticular ring wall, with clustered calcification center in the former and medial lines in the latter. Pocillopora and Porties are classified by distinctive dissepiments, columellae and septa. These microstructural skeleton characteristics were effective in the genus identification of fossil corals from drilled cores in the South China Sea. Eighteen detailed characteristics (ten of axial corallites, four of radial corallites, and four of coenosteum) were used in the Acropora species classification. The axial corallites size and structure (including corallite diameter, synapticular rings, and septa), the septa of radial corallites, and the arrangement of coenosteum were critical indicators for species identification. This identification guide can help paleoenvironmental and paleoecological analyses and modern coral reef conservation and restoration.     

Analyse de populations d'isastrées bajociennes (Scléractiniaires jurassiques de France). Conséquences taxonomiques stratigraphiques et paléoécologiques

The present statistical study of two Bajocian populationsof Isastrea from eastern France uses different methods of measurement taking into account the colonial character. The results of the univariate and the multivariate analyses together with direct observation of qualitative characters show that only two species are present in the samples: Isastrea bernardiana and I.tenuistriata. A new synonymy is suggested for the Bajocian species. Genera such as Andemantastraea All. and Parisastraea All. correspond to the common variation of Isastrea. The taxonomic position of other Jurassic Isastrea is examined. It is probably possible to use extreme morphotypes as stratigraphic markers owing to an eventual anagenesis.A comparison between the two samples denotes that the variation range or the mean value of some quantitative characters (number, thickness of septa, dimension of corallites, trabecular density) contributes to the paleoecological interpretation.The present paper emphasizes the necessity ofwell-defined species based preferably on population study, for a reliable generic definition.     

Growth characteristics of Protoheliolites norvegicus (Tabulata; Upper Ordovician; Estonia)

Protoheliolites is an early heliolitine coral characterized by closely spaced corallites separated in places by sparse coenenchyme. Growth characteristics in the type species, P. norvegicus, are revealed by detailed analysis based on serial peels and thin sections of coralla from the uppermost Katian of north‐western Estonia. Colonies of this species had a strong ability to recover from damage and partial mortality, resulting in various forms of rejuvenation, regeneration, fusion and reorganization of corallites; in some cases, this involved relatively large areas of undifferentiated soft parts. The shells of commensal cornulitids became enclosed in host coralla during colony growth. Coralla of P. norvegicus exhibit distinctive growth cycles due to responses to seasonal changes. The production of new corallites by coenenchymal increase usually occurred in low‐density bands, in which corallites generally display round to subrounded transverse outlines. In high‐density bands, the corallites became crenulated, their wall thickness increased, septal development was more pronounced, and the amount of coenenchyme increased. In addition to these cyclomorphic changes, there were significant astogenetic changes during growth. Compared with the early stage of colony development, distinctive characteristics in the late astogenetic stage include a decrease in the growth rate of the colony, better coordination among corallites, maximum development of corallite crenulations and septa in high‐density bands, more numerous coenenchymal tubules and a greater proportion of corallum area occupied by coenenchyme. In general, the role of polyps in determining morphological characteristics of individual corallites, such as tabularium area, corallite crenulations and wall thickness, was subordinate to the astogeny of the colony. Growth characteristics including colony‐wide coordination of polyp behaviour and subjugation of individuals to restore the colony following damage suggest a strong astogenetic control and high level of colony integration. Protoheliolites probably arose from a heliolitine genus rather than from a nonheliolitine group as some authors have proposed.     

Regularity in budding mode and resultant growth morphology of the azooxanthellate colonial scleractinian Tubastraea coccinea

Scleractinia exhibit a variety of growth forms, whether zooxanthellate or azooxanthellate, according to factors that control asexual reproduction and ensuing coral growth. The azooxanthellate branching scleractinian Dendrophyllia arbuscula shows regular modes of budding in terms of the locations of budding sites, the orientations of directive septa, and the inclination angle of budding throughout colonial growth. This study reports that such regularities are also found in the apparently different growth form of the massive dendrophylliid Tubastraea coccinea, which shows the following growth features: (1) the offsets (lateral corallites) always occur near four primary septa, except the two directive primary septa, meaning that the lateral corallites do not appear in the sectors of the two directive septa; (2) the two directive septa in lateral corallites tend to be oriented subperpendicular to the growth direction of the parental corallites; (3) the lateral corallites grow approximately diagonally upwards; and (4) these regularities are seen in the axial and derived lateral corallites among all generations during colony growth. Large differences in growth form are found between the branching D. arbuscula and massive T. coccinea, irrespective of the presence of specific regularities. It is likely that subtle modifications of certain parameters (e.g., budding interval, branch length, corallite size, and inclination angle of lateral corallites) have a strong effect on the overall growth morphology. A precise understanding of such regularities, which occur regardless of generation or taxonomic position, would contribute to understanding the “shape-controlling mechanism” of corals, which are an archetypal modular organism.     

Constraints on the formation of colonies of the extant azooxanthellate scleractinian coral Dendrophyllia arbuscula

Sentoku, A. & Ezaki, Y. 2011: Constraints on the formation of colonies of the extant azooxanthellate scleractinian coral Dendrophyllia arbuscula. Lethaia, Vol. 45, pp. 62–70. Scleractinia display a variety of growth forms, whether zooxanthellate or azooxanthellate, as the consequence of the combined effects of both intrinsic and extrinsic factors. New modules arise in colonial corals through asexual reproduction, including budding and division. The azooxanthellate, branching dendrophylliid Dendrophyllia arbuscula van der Horst 1922 , is a good species to investigate intrinsic regularities in budding, because: (1) the lateral corallites always occur in the vicinity of four primary septa, excluding the two directive primary septa; (2) the two directive septa in lateral corallites tend to be oriented almost perpendicular to the growth orientation of parental corallites; (3) the lateral corallites grow more‐or‐less diagonally upwards; and (4) these regularities are retained from the axial to the derived lateral corallites during colony growth. Accordingly, a colony of apparently complex dendroid corals is formed according to certain universal rules that apply to successive generations of corallites. The presence of two opposite sectors in which budding do not occur seems to be common to other azooxanthellate scleractinian families. Regularities, other than the orientation of the directive septa, are also commonly found at least in other azooxanthellate dendrophylliid genera. These regularities suggest the presence of strict developmental constraints on the asexual reproduction of the Scleractinia, both extant and extinct. These regularities by azooxanthellate scleractinians, as one of the representative colonial metazoan groups, provide us with fundamental data with which we can understand how colonies are constructed. □Azooxanthellate coral, budding, colony, Dendrophyllia arbuscula, regularity.     

Life-history strategies of a species of Catenipora (Tabulata; Upper Ordovician; southern Manitoba, Canada)

Detailed study of coralla by transverse serial sections permits the determination and evaluation of life-history strategies (survival and growth characteristics) in response to different physical environments, for Catenipora foerstei Nelson, 1963 from the Selkirk Member, Red River Formation, in Manitoba. We recognize various modes of corallite increase: one type of axial increase, four types of lateral increase, and agglutinated patches of corallites in association with normal, undamaged corallites; and one type of axial increase, one type of lateral increase, and temporary agglutinated patches from the recovery processes of corallites damaged by sediment or bioclast influx. In addition, the formation of new ranks by lateral increase is the most effective method for rapid growth of a corallum or for reconstructing part of a corallum damaged by physical disturbances. Fluctuations in the tabularial area of corallites occur in cycles over vertical intervals ranging from 3.20-7.90 mm. We consider each cycle to represent annual growth. Average annual growth of the three coralla ranges from 4.20-6.27 mm. According to correlations between annual growth cycles and other growth characteristics, a high frequency of offsetting is associated with rapid vertical growth. Specifically, annual growth is relatively high in association with episodes of sediment or bioclast influx, probably generated by storms. In some coralla, however, annual growth is highest in the cycle characterized by few new corallites or by extraordinarily high rates of offsetting by normal, undamaged corallites as well as damaged corallites. This suggests that vertical growth could also be affected by factors other than storm-related disturbance.     

Phenotypic plasticity in the reef corals Montastraea annularis (Ellis & Solander) and Siderastrea siderea (Ellis & Solander)

Mature colonies of Montastraea annularis (Ellis & Solander) and Siderastrea siderea (Ellis & Solander) were transplanted reciprocally between four reef environments near Discovery Bay, Jamaica. Multivariate analyses of variables describing corallite structures show that colonies of M. annularis change their skeletal morphology after transplantation from that characteristic of their original habitat to that characteristic of the environment to which they were moved. Control colonies of M. annularis, however, retain the morphology characteristic of their original habitat after manipulation. Many colonies of S. siderea similarly altered their morphology after transplantation, but some retained the morphology characteristic of their original habitat. Most control colonies of S. siderea did not change after manipulation. In general, control colonies of S. siderea show more morphologic variation between skeleton deposited before and after manipulation within colonies and also between colonies within populations, than did control colonies of M. annularis.These results indicate that, although M. annularis shows more plasticity than S. siderea. both species have highly plastic phenotypes. A large number of characters describing the architecture of corallites respond to environmental factors such as light intensity, sedimentation rate, water activity, and food availability. The most plastic characters in M. annularis describe coenosteal features and the thickness of thecae. The most plastic characters in S. siderea describe the thicknesses of thecae. septa, and columellae.This study suggests that phenotypic plasticity is an important species attribute in scieractinians and may be a significant mechanism in controlling the distribution and abundance of scleractinians on reefs.     

Genetic control of septal numbers and the species problem in a fossil solitary scleractinian coral

Intraspecific morphological variations of a Pleistocene solitary scleractinian coral, Cylindrophyllia orientatis (Yabe & Eguchi), have been examined based on 792 specimens. The specimens are discoidal to short cylindrical in shape, with no significant change in their diameter during skeletal growth. Septal arrangements of the coralla are observed on upper and basal surfaces. Septal numbers do not change through the ontogeny of each corallum, even when the last cycle of septa is incomplete. Septal arrangements and numbers are controlled by intrinsic genetic factors. Heights of the coralla are controlled by environmental factors where they lived If growth rates are presumed to be constant, heights can be regarded as indicating age of specimens. Assuming that this is the case, the survivorship curve shows that this fossil population had a constant death rate. Two varieties exist in this population: one has 20–28 septa, the other 30–48 septa, showing a dimorphic feature. Scleractinian coral, intraspecific variation, population, septa, species problem ,     

Cyphastrea kausti sp. n. (Cnidaria,Anthozoa, Scleractinia), a new species of reef coral from the Red Sea

A new scleractinian coral species, Cyphastrea kausti sp. n., is described from 13 specimens from the Red Sea. It is characterised by the presence of eight primary septa, unlike the other species of the genus, which have six, ten or 12 primary septa. The new species has morphological affinities with Cyphastrea microphthalma, from which it can be distinguished by the lower number of septa (on average eight instead of ten), and smaller calices and corallites. This species was observed in the northern and central Red Sea and appears to be absent from the southern Red Sea.     

Quality Evaluation of Potentilla fruticosa L. by High Performance Liquid Chromatography Fingerprinting Associated with Chemometric Methods

The present study was performed to assess the quality of Potentilla fruticosa L. sampled from distinct regions of China using high performance liquid chromatography (HPLC) fingerprinting coupled with a suite of chemometric methods. For this quantitative analysis, the main active phytochemical compositions and the antioxidant activity in P. fruticosa were also investigated. Considering the high percentages and antioxidant activities of phytochemicals, P. fruticosa samples from Kangding, Sichuan were selected as the most valuable raw materials. Similarity analysis (SA) of HPLC fingerprints, hierarchical cluster analysis (HCA), principle component analysis (PCA), and discriminant analysis (DA) were further employed to provide accurate classification and quality estimates of P. fruticosa. Two principal components (PCs) were collected by PCA. PC1 separated samples from Kangding, Sichuan, capturing 57.64% of the variance, whereas PC2 contributed to further separation, capturing 18.97% of the variance. Two kinds of discriminant functions with a 100% discrimination ratio were constructed. The results strongly supported the conclusion that the eight samples from different regions were clustered into three major groups, corresponding with their morphological classification, for which HPLC analysis confirmed the considerable variation in phytochemical compositions and that P. fruticosa samples from Kangding, Sichuan were of high quality. The results of SA, HCA, PCA, and DA were in agreement and performed well for the quality assessment of P. fruticosa. Consequently, HPLC fingerprinting coupled with chemometric techniques provides a highly flexible and reliable method for the quality evaluation of traditional Chinese medicines.     

Life‐history strategies of Manipora amicarum Sinclair, 1955 (Tabulata; Upper Ordovician; southern Manitoba,Canada)

Based on detailed study of transverse serial sections, we recognize various modes of corallite increase in a multichain cateniform coral, Manipora amicarum from the Selkirk Member, Red River Formation, in Manitoba. One type of axial increase and four types of lateral increase involve normal, undamaged corallites, and one type of axial increase and one type of lateral increase occur during recovery processes of corallites damaged by sediment or bioclast influx. All but one of these types of increase are comparable to those in a single‐chain coral, Catenipora foerstei, which we previously documented from the same stratigraphic unit and locality. In M. amicarum, the formation of double ranks and agglutinated patches of corallites by normal corallites, and by recovery processes following corallite damage, is common and presumably genetically controlled. Agglutinated patches originate differently in C. foerstei, occurring sporadically or temporarily in only some coralla. Average annual vertical corallum growth in M. amicarum, as indicated by cyclic fluctuations of tabularial area, is higher than in C. foerstei, which has comparatively smaller corallites. In general, annual growth in M. amicarum is positively correlated with average tabularial area, negatively correlated with frequency of damaged corallites, and is not related to the frequency of corallite increase. In C. foerstei, however, there is a positive association between annual growth rate and the frequency of increase by damaged corallites, related to episodes of sediment or bioclast influx probably generated by storms. In comparison with C. foerstei, M. amicarum has a low frequency of corallite termination and extensive partial mortality is rare. It seems that the relatively rapid overall vertical corallum growth in M. amicarum was effective for protecting the coral from unfavourable situations, possibly by maintaining the growth surface higher above the substrate than in C. foerstei. Although these two species show many similarities in the types of corallite increase, their reactions and strategies in relation to physical disturbance were quite different.     

Favia camranensis sp. n. (Scleractinia: Faviidae), a new coral species from Southern Vietnam

A new species of coral, Favia camranensis sp. n., from the Hon Nai reef, Cam Ranh Bay, in southern Vietnam is described. This coral differs from all known faviids in that its corallites project one above another by more than 2 mm. The septa and septa-costae are heavily ornamented with complexly serrated trabecular spines. This coral can form monospecific aggregations of 5–20 colonies.     

GENETIC, MORPHOLOGICAL, AND TOXICOLOGICAL VARIATION AMONG GLOBALLY DISTRIBUTED STRAINS OF NODULARIA (CYANOBACTERIA)

Morphological, toxicological, and genetic variation was examined among 19 strains of Nodularia. The strains examined could be morphologically discriminated into four groups corresponding to N. spumigena Mertens, N. sphaerocarpa Bornet et Flahault, and two strains that did not clearly correspond to currently accepted Nodularia species. Genetic variation was examined using nucleotide sequencing of the phycocyanin intergenic spacer region (cpcBA-IGS) and RAPD-PCR. The PCR-RFLP of the cpcBA-IGS differentiated four genotypes corresponding to the four morphological groups. However, nucleotide sequencing of 598 bp of the 690-bp fragment showed that one of the three strains corresponding to N. sphaerocarpa (PCC 7804) was genetically divergent from the other two, suggesting that it constitutes a distinct species. Nucleotide variation within the morphospecies groups was limited (<1%), and all 14 Australian strains of N. spumigena possessed identical cpcBA-IGS sequences. The RAPD-PCR differentiated the same groups as the cpcBA sequencing and discriminated each of the seven different Australian populations of N. spumigena. Strains from within a bloom appeared genetically identical; however, strains isolated from different blooms could be separated into either a western or a southeastern Australian cluster, with one strain from western Australia showing considerable genetic divergence. The pattern of variation suggests that individual blooms of N. spumigena are clonal but also that Australian N. spumigena populations are genetically distinct from each other. Examination of genetic distance within and between blooms and within and between morphological groups showed clear genetic dicontinuities that, in combination with the cpcBA-IGS data, suggest that Nodularia contains genetically distinct morphospecies rather than a continuous cline of genetic variation. Furthermore, these morphospecies are genetically variable, exhibiting hierarchical patterns of genetic variation on regional and global scales. Production of the hepatotoxin nodularin was not restricted to one genetic lineage but was distributed across three of the five genotypic groups. A strain of N. spumigena from a nontoxic Australian population was found to fall within the range of genetic variation for other toxic Australian strains and appears to be a unique nontoxic strain that might have arisen by loss of toxin production capacity.     

Intraspecific Phenotypic Variation and Morphological Divergence of Strains of Folsomia candida (Willem) (Collembola: Isotomidae), the "Standard" Test Springtaill

We describe and compare the external morphology of eleven clonal strains and one sexual lineage of the globally distributed Folsomia candida, known as “standard” test Collembola. Of the 18 morphological characters studied, we measured 14 to have significant between-strains genetic variations, 9 of these had high heritabilities (>78%). The quantified morphological polymorphism was used to analyse the within-species relationships between strains by using both a parsimony analysis and a distance tree. These two detailed morphological phylogenies have revealed that the parthenogenetic strains grouped themselves into two major clades. However the exact position of the sexual strain remains unclear and further analysis is needed to confirm its exact relationship with the parthenogenetic ones. The two morphologically based clades were found to be the same as the ones previously described using molecular analysis. This shows that despite large within-strain variations, morphological characters can be used to differentiate some strains that have diverged within a single morphospecies. We discuss the potential evolutionary interpretations and consequences of these different levels of phenotypic variability.     

Genetic and morphological divergence within the Sebastes pachycephalus complex (Scorpaeniformes: Scorpaenidae)

Genetic and morphological divergence among the four subspecies in the Sebastes pachycephalus complex (S. pachycephalus pachycephalus, S. p. nigricans, S. p. nudus and S. p. chalcogrammus) was clarified. Principal coordinate analysis (PCoA) based on AFLP clearly divided 55 specimens of the complex into two groups, the S. p. pachycephalus?CS. p. nigricans group (P-Ni group) and the S. p. nudus?CS. p. chalcogrammus group (Nu-C group), although three specimens occupied intermediate positions. The minimum spanning network (MSN) based on partial sequences of the mitochondrial control region (mtCR) failed to separate either the P-Ni and Nu-C groups or the four subspecies into distinct clades, although restricted gene flow and genetic differentiation between the former were indicated by the F _ST estimation. Differences in morphological characters, including counts of pectoral fin rays and counts of dorsal fin spines lacking basal scales, were also evident between the two groups. However, little or no genetic or morphological difference was found between the two subspecies within each group. It was concluded that the P-Ni and Nu-C groups of the S. pachycephalus complex actually represent two different species, which is further supported by their sympatric distribution. Differences in dorsal body coloration and the presence or absence of brown spots on the ventral surface, which were formerly used to discriminate between four ??subspecies,?? may simply represent intraspecific variation. The three specimens occupying intermediate positions in the AFLP PCoA also occupied equivocal positions between the two species in the principal component analysis (PCA) based on morphometric characters, suggesting that they were hybrids between the two species. The star-shaped MSN of mtCR, which lacks distinct clades representing the two species, may be due to not only interspecific hybridization but also the sharing of ancestral haplotypes.     

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.     

Effects of plant hybridization on the structure and composition of a highly rich community of cynipid gall wasps: the case of the oak hybrid complex <Emphasis Type="Italic">Quercus magnoliifolia</Emphasis> x <Emphasis Type="Italic">Quercus resinosa</Emphasis> in Mexico

The richness and composition of herbivore communities can be influenced by the genetic variation of host plants. Hybrid plant populations are ideal to test these effects because they usually harbor high genetic variation and display a mosaic of phenotypic characters. The goal of this study was to examine the effect of hybridization between two Mexican white oaks, Q. magnoliifolia and Q. resinosa, on the composition and diversity of the associated cynipid gall wasp community. We used eight nuclear microsatellite markers to genotype 150 oak individuals sampled at three different altitudes at the Tequila volcano and conducted monthly samplings of galls in each individual over the course of 2 years. A Bayesian assignment analysis indicated genetic admixture between the two oak species at the study site and allowed classifying individuals as Q. magnoliifolia, Q. resinosa or hybrids. Gall morphospecies richness was significantly higher in the hybrids, intermediate in Q. magnoliifolia and lower in Q. resinosa. Overall, 48 different gall morphospecies were found, with 21 of them being shared among the three groups of plants, 13 between two groups of plants, and 14 were unique to one group of plants, with eight of these being found in hybrids. Several of the shared galls showed differences in abundance among plant groups. Therefore, genetic structure in this oak complex significantly influences the diversity and composition of the associated gall wasp community, and hybrid individuals are probably acting as potential sinks and bridges for the colonization of plant hosts by these highly specialized insect species.     

Regular and flexible modes of division and hystero-ontogenetic growth in the Silurian rugose coral Stauria favosa

New modules arise in colonial corals as the result of asexual reproduction. The Silurian rugosan Stauria favosa ordinarily exhibits cerioid coralla with a characteristic cross-shaped axial structure and a typical pattern of parricidal increase. Quadripartite increase at the sites of the four protosepta is most common, whereas cases of tripartite increase are rare. Parental protosepta are transformed into dividing walls, where the four protosepta first appear with a definite polarity in offset corallites. Daughter corallites inherit metasepta as metasepta, and catasepta as catasepta, within the same quadrants as those of the parent. Metasepta are inserted serially, following Kunth's rule, as is characteristic of rugosan protocorallites. As each daughter corallite derived immediately from the same parent is arranged with identical polarity, it grows equally and evenly both individually and as a group. Daughters thus form protosepta and metasepta under strict phylogenetic and developmental constraints. However, individual corallites grow and reproduce autonomously, by using all available skeleton and space of the parent. Although each module cannot modify essential modes of division, flexibility of the system was via changes in the density and arrangement of corallites, and regulating modes of growth, in tandem with adjacent corallites within the corallum. It is probable that regularity, due to constraints of several origins, as well as flexibility are typical of other rugosan colonies and played an important role in growth dynamics between corallites and corallum.     

Evidence for extensive cryptic speciation in trematodes of butterflyfishes (Chaetodontidae) of the tropical Indo-West Pacific

Molecular data from the cytochrome c oxidase subunit I (cox1) mitochondrial DNA gene and the second internal transcribed spacer (ITS2) nuclear rDNA region were used to test the current morphologically-based taxonomic hypothesis regarding species of Monorchiidae (Hurleytrematoides) from chaetodontid and tetraodontid fishes from six sites in the tropical Indo-West Pacific (TIWP): Heron and Lizard Islands off the Great Barrier Reef (GBR, Australia), Moorea (French Polynesia), New Caledonia, Ningaloo Reef (Australia) and Palau. The 16 morphospecies analysed differed from each other by a minimum of 55 bp (9.1%) over the mitochondrial cox1 and 8 bp (1.6%) over the ITS2 DNA regions. For two species, Hurleytrematoides loi and Hurleytrematoides sasali, specimens from the same host species in sympatry differed at levels comparable to those between pairs of distinct morphospecies for both cox1 and ITS2 sequences. We take this as evidence of the presence of combinations of cryptic species; however, we do not propose new species for these taxa because we lack identified morphological voucher specimens. For seven species, Hurleytrematoides coronatum, Hurleytrematoides deblocki, Hurleytrematoides faliexae, H. loi, Hurleytrematoides morandi, H. sasali and Hurleytrematoides sp. A, samples from some combinations of localities had base pair differences that were equal to or greater than differences between some pairs of distinct morphospecies for one or both cox1 and ITS2 sequences. For three species, H. coronatum, H. loi and H. morandi, one haplotype differed from every other haplotype by more than the morphospecies benchmark. In these cases morphological specimens could not be distinguished by morphology. These data suggest extensive cryptic richness in this genus. For the present we refrain from dividing any of the morphospecies. This is because there is a continuum of levels of intra- and interspecific genetic variation in this system, so that distinguishing the two would be largely arbitrary.