The biological reconstruction of Tetradium Dana, 1846

The Ordovician fossil Tetradium   Dana, 1846 typically had aragonite tubes with millimetre-size subsquare cross-sections, fourfold symmetry and an inward-projecting septum along the midline of each wall. It increased by axial quadripartite division into four subequal parts when the septa grew together in the centre of the tube. Tetradium is usually classified as a chaetetid sponge or a tabulate coral. However, it is shown that in animals, fourfold symmetry occurs only as a secondary adaptation in medusae, and axial quadripartite division into four subequal parts is unknown. In contrast, both of these characteristics are common in algae. Tetradium is classified here as a rhodophyte, a calcified corticated uniaxial florideophyte. The anatomy of Recent rhodophytes is used to model the living Tetradium , and their branching is used to model growth by axial quadripartite division. The reconstructed microanatomy of the living Tetradium has (1) an uncalcified axial filament of elongated cells, (2) whorls of four lateral axes, rarely calcified and therefore rarely preserved as tabulae, that radiated from each cell of the central filament, and (3) a weakly calcified cortex that formed the subsquare tube and extended into the inward-projecting septa. Aragonite precipitation within the cortex was probably entirely intercellular, and produced a lightly calcified skeleton. Each reconstructed skeletal tube extended distally into a somewhat flexible, photosynthesizing and nutrient-absorbing part of the alga. Holdfasts were weak. This study shows that reconstructing the anatomy of an enigmatic fossil, instead of just comparing hard parts, significantly improves the reliability of its taxonomic identification.     

Chaetetid growth form and its controlling factors

Chactetid sponge morphology is examined to provide details on growth styles and their controlling factors. Chactetid growth forms range from laminar to domical. bulbous. columnar and complex branching in a variety of sizes. The chactetid skeleton began as a laminar unit comprising growth of many calicles across the substrate at the same time. Several styles of early growth. involving differential calicle growth rates and varying directions of adjacent calicle growth. are recognized. and result in complex arrangements of caliclcs in the skeleton. Despite this. the cross-sectional protile of the gross morphology at any stage of growth is usually a simple outline. implying that internal complexities of calicle development are modulated to produce an optimum cross-sectional outline for the individual chactetid. The morphological range of chactetids is similar to stromatoporoids. some tabulate. heliolitid and colonial rugose corals. some bryozoans. stromatolites. encrusting foraminifera and calcareous algae: the common environmental controlling factors of sedimentation and turbulence profoundly influenced growth form in all these organisms by virtue of their common sessile shallow marine habit. Chactetid growth forms show a general relationship to the environment: columnar and branching forms grew in quiet water. while laminar and domical were better adapted to environments of higher energies. The environmental adaptations of laminar forms. however. remain problematic. because they are found in both high and low energy facies. and interpretation depends strongly on facies study. Also. interpretation of all growth forms is suspected to relate to taxonomic aspects. as has been recognized for other groups. Unfortunately. chaetetid taxonomy is in need of revision. and at present no certain relationship has been demonstrated between taxonomy and growth form. Some modern calcareous sponges with a chaetetiform architccture also show similarities in growth form to fossil types. and may be subject to similar controls. □Chaetetid. calcified sponge. growth form. Pennsyloanian. North America.     

Growth-interruption surfaces within chaetetid skeletons: Records of physical disturbance and depositional dynamics

Records of growth interruptions within spongiomorph and colonial skeletons provide a unique window into the disturbance dynamics of ancient shallow marine benthic environments at ecological time scales. The utility of growth-interruption surfaces for inferring the frequency of physical disturbance and the relative rate of sediment accumulation is illustrated by chaetetid skeletons from several Middle Pennsylvanian (Desmoinesian) sequences of southeastern Kansas. Five different growth-interruption surfaces are recognized within these calcareous demos-ponges: (1) breaks in growth with apparent continuity of tubules across the surface, (2) surfaces of rejuvenation or recolonization with reorientation of tubules, (3) sediment-filled tubules or trapped sediment partings, (4) encrusted surfaces, and (5) biocorroded or bored surfaces. A single skeleton may contain several types of surfaces, and individual surfaces may change in character across the skeleton. The type and spacing of growth-interruption surfaces vary with chaetetid growth form. Together with growth form, these surfaces provide a basis for paleoen-vironmental interpretation.     

Species diversity and ecological range in relation to ploidy level in the flora of the Pyrenees

Polyploidy is a major process in plant evolution. Surprisingly, no study has examined its role in species diversification and ecological distribution in relation to other life history traits. In this study, we examine to what extent polyploidy and the other traditionally examined biological traits (pollination mode, dispersal mode and growth form) account for ecological and taxonomic diversity in the flora of the Pyrenees. Fifty genera (in 22 angiosperm families) were classified according to ploidy level, growth form, pollination mode and dispersal mode, and 451 species and/or subspecies in these 50 genera were classified according to ploidy level and growth form. We examined the contribution of ploidy level, pollination and dispersal modes and growth form to (i) the ecological range of species and genera, i.e., the number of natural habitats (defined by a combination of ecological characteristics) where they occur, and (ii) the taxonomic diversity of the 50 genera. Ploidy level and dispersal mode had significant effects on the taxonomic diversity of the 50 genera. Taxonomic diversity, but not polyploidy per se, was significantly correlated with ecological range of genera. For individual species, diploids had a larger ecological range than polyploids, and herbaceous growth forms had wider ecological distributions than other growth forms. Our results indicate that polyploidisation may be a source of ecological diversification of genera, not by increasing the ecological range of particular polyploid species compared to diploids, but rather by creating taxonomic diversity that leads in some genera to a diversification of the habitats occupied by different ploidy levels. This observation is consistent with previous observations of ecological divergence of chromosomal races in some species in the Alps and in the Pyrenees. As found in other studies, species diversification in the studied flora appears to be greatly influenced by the occurrence of multiple dispersal modes, while ecological range of species or subspecies is significantly increased by the presence of herbaceous species.     

Paleoecologic,temporal, and spatial analysis of early Silurian Reefs of the Chicotte Formation,Anticosti Island,Quebec, Canada

Summary Reefs of the Lower Silurian Chicotte Formation are the largest and most faunally diverse known on Anticosti Island, Quebec. They reach up to 25 m in thickness and 250 m in diameter and are present predominantly at two intervals, forming a lower and upper reef cluster. Remnants of bioherms are represented on the present-day wave-cut terrace as 60 to 100 m diameter, subcircular erosional depressions known as Philip structures or as outcrop. The bioherms were relatively low structures, with approximately 3 to 5 m maximum synoptic relief, some of which developed on hardgrounds and possible paleokarst surfaces of crinoidal wackestone and packstone. Dominant skeletal framework builders and sediment producers within all of the reefs are laminar to low domical stromatoporoids, colonial cerioid and fasciculate rugose corals, colonial tabulate corals, and cryptostome bryozoans. Vertical zonation of reef biota is evident within well-exposed reefs of the lower reef cluster. Three to four stages are recognizable:1) a low-diversity tabulate coral-dominatedpioneering community including large tabulate coral colonies (halysitids and favositids), and few stromatoporoids (clathrodictyids, ecclimadictyids), fasciculate rugosans, large generally monotypic stalked crinoids, and shelly benthos (brachiopods, few ostracodes and trilobites);2) an intermediate- to high-diversity, mixed tabulate coral-stromatoporoid-dominatedreef-core community;3) a slightly lower diversity stromatoporoid-tabulate coral-dominatedclimax community with laminar coenitids and alveolitids; and,4) in a few localities, a capping, low-diversity tabulatecoral-dominated (alveolitid and coenitid), and stromatoporoid-bearing community comprising laminar forms. Amelioration of Early Silurian climates, following Late Ordovician glaciation, allowed gradual reestablishment of extensive shallow-water reef growth, by mainly new and increasingly diverse genera and species of metazoans. Reef development within the Chicotte Formation coincided with global, widespread development of latest Llandovery and earliest Wenlock reefs in subtropical to tropical areas. Chicotte reefs have broad characteristics, in terms of overall biotic composition, vertical successions recognized, and paleogeographic setting, similar to those of equivalent and slightly younger age from intracratonic settings in Baltica (Gotland, Sweden and Estonia) and central and northern Laurentia (Midcontinent, U.S.A.; Hudson Bay, Canada; and North Greenland, Denmark).     

广东古兜山自然保护区蕨类植物群落的特征

通过对广东新会古兜山自然保护区中108个5m ×5m的蕨类植物样方调查,初步分析了样方中蕨类植物的种类组成和区系特点及种群的多度、频度、重要值、蕨类的生长型、叶的性质和群落的外貌、季相等群落学特征。结果表明:(1)古兜山自然保护区的蕨类植物种类具有典型的南亚热带植物区系特点,热带亚洲植物区系成分对古兜山蕨类植物区系有强烈影响;(2)由于蕨类植物种群的随机分布和环境因子的异质性,种群的多度和重要值分布表现出明显的正态分布规律;(3)样方中蕨类植物的形态外貌、叶的性质及其群落的外貌和季相均表现出典型的南亚热带蕨类植物群落特征;古兜山自然保护区的蕨类植物可划分为花篮状蕨类、树蕨类、匍匐类、攀援类、附生类5种生长型类型。     

Environmental distribution of colony growth form in the favositid Pleurodictyum americanum

Pandolfi, John M. & Burke, Collette D. 1989 01 15: Environmental distribution of colony growth form in the favositid Pleurodictyum americanum. Lethaia , Vol. 22, pp. 69–84. Oslo. ISSN 0024–1164.
Colony growth form is of fundamental importance to understanding the ecology of both modern and ancient marine sessile colonial animals. Fourier shape analysis of the coral Pleurodictyun americantum (Tabulata: Favositida) from the Middle Devonian Hamilton Group of New York State, indicates that colony growth form is variable between environments. Discriminate function analysis of harmonics 2–6 of 51 assemblages of Pleurodictyum americanum (N = 1900) shows that this species displays an onshore to offshore gradient in colony shape. Offshore environments characterized by low levels of turbidity, oxygen, and light contain more flattened, less hemispherical growth forms, whereas onshore environments characterized by high levels of turbidity, oxygen, and light contain more hemispherical, less flattened growth forms. Harmonic shape analysis detected subtle differences among samples of P. americanum from different environments, but also showed that distinctive morphotypes are distributed within horizons. as well as between them. In fact, no one-to-one correspondence in growth form to environment is apparent; growth forms are distributed within environments, suggesting that genetic factors may have had a greater influence over coral growth form than environment. In tabulate corals, patterns of within species variability must be determined before growth form may be useful in interpreting ancient environments. □ Tabulate coral, Fourier shape analysis, morphological variability, growth form, Devonian, Hamilton Group, New York .     

A preliminary phylogeny of the 'didymocarpoid Gesneriaceae' based on three molecular data sets: Incongruence with available tribal classifications

The 'didymocarpoid Gesneriaceae' (traditional subfam. Cyrtandroideae excluding Epithemateae) are the largest group of Old World Gesneriaceae, comprising 85 genera and 1800 species. We attempt to resolve their hitherto poorly understood generic relationships using three molecular markers on 145 species, of which 128 belong to didymocarpoid Gesneriaceae. Our analyses demonstrate that consistent topological relationships can be retrieved from data sets with missing data using subsamples and different combinations of gene sequences. We show that all available classifications in Old World Gesneriaceae are artificial and do not reflect natural relationships. At the base of the didymocarpoids are grades of clades comprising isolated genera and small groups from Asia and Europe. These are followed by a clade comprising the African and Madagascan genera. The remaining clades represent the advanced Asiatic and Malesian genera. They include a major group with mostly twisted capsules. The much larger group of remaining genera comprises exclusively genera with straight capsules and the huge genus Cyrtandra with indehiscent fruits. Several genera such as Briggsia, Henckelia, and Chirita are not monophyletic; Chirita is even distributed throughout five clades. This degree of incongruence between molecular phylogenies, traditional classifications, and generic delimitations indicates the problems with classifications based on, sometimes a single, morphological characters.     

Shape analysis of two sympatric coral species: Implications for taxonomy and evolution

Fourier shape analysis of Pleurodictyum americanum and P. dividua , favositid tabulate corals, from the Middle Devonian Hamilton Group of New York State, indicates that colony growth form is variable within species between environments, but that the range of variability in growth form is static through time. Pleurpdictyum dividua displays a columnar morphotype; however, P. dividua and P. americanum cannot be discriminated from one another based on colony shape alone. A major prediction of the punctuated equilibrium model of evolution is morphological stasis throughout the duration of a species. Harmonic means of assemblages of P. americanum show no persistent temporal trends. The range of harmonic means present among the oldest assemblages (Centerfield Limestone) are comparable to those among the youngest assemblages (Windom Shale) and to those in the intervening intervals. Character stasis in colony growth form lasted throughout a 2.5-3.5 my interval. In tabulate corals, where reproductive modes such as fragmentation have not been demonstrated, growth form may be useful in interpreting ancient environments. In addition, the tempo of evolution of growth form can be analyzed when sufficient morphological data are available from a wide distribution of environments. Thus, Fourier shape analysis of growth form provides a powerful tool for paleontologists to interpret the ecology and evolution of colonial marine animals.     

Evolution of shrub-like growth forms in the lianoid subfamily Secamonoideae (Apocynaceae s.l.) of Madagascar: phylogeny, biomechanics, and development

Lianas are common in the Apocynaceae s.l. and are predominant in the subfamily Secamonoideae. Shrub-like taxa are rare within this subfamily but occur in Malagasy genera such as Secamone, Secamonopsis, and Pervillaea. We explored the evolutionary appearance of shrub-like growth forms in Malagasy Secamonoideae through a molecular phylogeny using chloroplastic sequences. The phylogeny revealed several independent appearances of shrub-like growth forms within the Secamonoideae. Biomechanics and development of the shrub-like growth form were detailed in one species, Secamone sparsiflora, which has upright and self-supporting young stems that become procumbent in older stages of development. Biomechanical investigations revealed characteristics atypical of both lianas and self-supporting shrubs. Anatomical development in S. sparsiflora is initially similar to lianas in the same clade but shows potentially neotenic retention of juvenile wood development for most of the growth trajectory. The results suggest that evolution of lianescence can carry a high degree of specialization and developmental burden that might limit evolution back to self-supporting growth forms. Under certain geographic and ecological conditions, such as geographic isolation, xeric conditions and/or reduced biotic competition, escapes from lianescence to other growth forms can occur in some angiosperm groups via relatively simple heterochronic shifts of mechanically significant growth processes.     

Eriophyoid Mites (Acariformes,Eriophyoidea) from Rosaceae: Taxonomic Diversity,Host-Parasite Relationships,and Ability to Cause Galls

A review on the complex of species of eriophyoid mites associated with Rosaceae is given, focused on the phylogeny, biology, and distribution of their host plants and galls induced by these mites. About 200 species of 39 genera from 3 families ofEriophyoidea are known from Rosaceae. Among them, 6 species from 2 genera belong to Phytoptidae, 178 species from 27 genera, to Eriophyidae, and 28 species from 10 genera, to Diptilomiopidae; 7 genera of the latter family are represented on Rosaceae by a single species each. The ability to induce galls is discussed using the example of the most widespread and numerous genera of the family Eriophyidae from Rosaceae. Mites of two large subfamilies, Eriophyinae and Phyllocoptinae, include both vagrant and concealed forms. The types of galls caused by mites are related to the systematic position of mites and the distribution of mites and their host plants. The hypothesis of host shifts of eriophyoid mites from other plant families to Rosaceae is considered. Most of the species which presumably switched to Rosaceae have been described from Southeast Asia. Morphological similarity between vagrant and concealed forms from the paraphyletic tribes Eriophyini and Phyllocoptini, and also Aceriini and Anthocoptini is discussed. Their pairwise similarity might be the result of evolution (Eriophyini → Phyllocoptini and Aceriini → Anthocoptini) connected with change oflife style.     

Molecular phylogeny and biogeography of tribe anthemideae (Asteraceae), based on chloroplast gene ndhF

Anthemideae (Asteraceae) is primarily a north temperate, Old World tribe of 109 genera and approximately 1740 species. We sequenced a 1200-bp portion of chloroplast gene ndhF for representative genera and subtribes and constructed a phylogeny for the tribe. There is support for monophyly of subtribes Chrysantheminae and Gonosperminae and for portions of some subtribes. However, our molecular phylogeny differs significantly from traditional classifications and from previously published morphological phylogenies of the tribe. Many South African genera from several different subtribes form a basal grade, indicating multiple, relictual lineages. Eurasian genera form a recently derived clade that includes the Mediterranean genera of the Iberian Peninsula and North Africa. There is little resolution or support for the placement of eastern Asian genera. Apparently, the tribe originated in the Southern Hemisphere, presumably in Africa, with the Eurasian and Mediterranean members being derived from a common ancestor.     

喀斯特山地高校苔藓植物多样性及环境响应——以贵州大学为例

以贵州大学喀斯特山地校园为对象,调查其苔藓植物物种多样性及其生境特征,探讨苔藓植物生长与环境的关系。结果表明,研究区域内苔藓植物共12科27属51种。优势科是丛藓科(Pottiaceae)、青藓科(Brachytheciaceae)和灰藓科(Hypnaceae);主要生活型为丛集型、交织型和垫型;不同功能区域的苔藓植物生物多样性从高到低依次为行政办公区、休闲游憩区、教学科研区、体育运动区、宿舍休息区;不同生境物种丰富度从高到低依次是疏林草坪、林下、草坪环境、灌丛花池、道路;人为干扰程度与光照、湿度是影响苔藓植物多样性组成的重要因子。研究区域内苔藓植物多样性较低,多为土生藓类。在苔藓生长的微生境中,人为干扰低、空气湿度大的林地、疏林草坪更利于苔藓生长。     

Neoselachian (Chondrichthyes, Elasmobranchii) diversity across the Cretaceous-Tertiary boundary

Fishes are often thought to have passed through mass extinctions, including the Cretaceous-Tertiary (KT) event, relatively unscathed. We show that neoselachian sharks suffered a major extinction at the K/T boundary. Out of 41 families, 7 became extinct (17±12%). The proportional measure increases at lower taxic levels: 56±10% loss of genera (loss of 60 out of 107) and 84±5% loss of species (loss of 182 out of 216). However, the Maastrichtian and Danian are characterized by a high number of singleton taxa. Excluding singletons we have calculated a 34±11% loss of genera and a 45±9% loss of species. The simple completeness metric (SCM) for genera displays a decrease from the Maastrichtian (94%) to the Danian (85%) indicating a rather complete fossil record of neoselachian genera. The extinctions were heavy among both sharks and batoids (skates and rays), but most severe among batoids, which lost almost all identifiable species. There were equal losses among open marine apex predators (loss of Anacoracidae, Cretoxyrhinidae, and Scapanorhynchidae) and durophagous demersal forms from the continental shelf and shallow seas (Hypsobatidae, Parapaleobatidae, Sclerorhynchidae, Rhombodontidae). Benthopelagic and deep-sea forms were apparently little affected. New families with similar ecological roles (Carcharhinidae, Isuridae, Torpedinidae) replaced these families in the Danian, and full diversity of the different shark and batoid groups had been recovered by the end of the Paleocene or early Eocene. Sharks and rays suffered levels of extinction entirely in line with other groups of organisms at the K/T extinction event.     

The Pleistocene glaciations and the evolutionary history of the polytypic snail species Arianta arbustorum (Gastropoda, Pulmonata, Helicidae)

The evolutionary history of the snail Arianta arbustorum is controversial. This diverse, polytypic species has two distinct forms: one, with a globular shell and closed umbilicus, is found from lowland to high altitudes; the other, with a depressed shell and open umbilicus, is found at a few scattered, high altitude localities. What is the origin of these two forms? Some believe that the depressed shell is a recent, local, ecotypic adaptation to alpine environments. Others believe that this form is a relic of an ancestral condition that may have survived the Pleistocene glaciations on nunatak-like montane refugia, while the globular shell is a derived condition and its presence at high altitudes follows post-Pleistocene recolonisation. We analysed a portion of the mitochondrial gene cytochrome oxidase I for 100 snails of the species A. arbustorum, three additional Arianta species, and nine outgroup taxa from five genera, in order to understand the phylogeographic history of the species. Despite some confounding artefacts that are likely due to introgression among the morphological forms, the resulting phylogeny shows that the depressed shell is plesiomorphic, while the globular shell is derived. Moreover, their disparate histories suggest that the depressed shell variety survived the glaciations in pockets of alpine refugia, while the globular shell variety recolonised the alpine environment post-glacially.     

Vegetation Heterogeneity and Life-Strategy Diversity in the Flora of the Heterogeneous Landscape of Nizanda, Oaxaca, Mexico

We updated the floristic checklist of the Nizanda region, Isthmus of Tehuantepec (southern Mexico), characterized the occurring plant communities based on dominant species, and described the region’s flora according to life form, growth form, growth type, and growth habit spectra. Ten years of botanical exploration, along with surveys in 188 100-m² samples from different vegetation types, provided the baseline floristic information. Ordination and classification analyses were performed to examine the degree of differentiation between communities. Geographical ranges of all species were used to assess biogeographical relationships of this flora. The inventory includes 920 species (553 genera, 124 families). More than one-third of the families were represented by a single species, whereas the 10 richest families had 43% of the species richness. Dendrograms showing plot classification at three taxonomic levels (species, genus and family) revealed savannah as the most strongly differentiated community amid seven vegetation types. Regarding growth forms, forbs and trees prevailed. Phanerophytes were the most common life form category, whereas herbs and woody plants were the dominant growth types. The largest richness for all taxonomic levels was recorded in the tropical dry forest. The expanded floristic knowledge gained for the Nizanda region provided better criteria to revise the classification scheme of its vegetation. Our preliminary biogeographical analysis illustrates the role of the Isthmus of Tehuantepec as a corridor for thermophilous floras between two oceanic watersheds, and as a natural distributional limit for several Mesoamerican plant species.     

The Ordovician acritarch genera Tranvikium and Ampullula: their relationship and taxonomy

A restudy of the Ordovician (Arenig-Llanvirn) acritarch taxa Tranvikium polygonale Tynni, 1982, and Ampullula suetica Righi, 1991, indicates that they represent extremes in a single morphological plexus. At one extreme are forms with a polar 'excystment' aperture (closed by an operculum or two opercular pieces) and a smaller opening (plugged or open) at the opposite pole; at the other are forms lacking a polar aperture but having, at the opposite pole, a tube open distally and plugged or open basally. New morphological terms for these structures are proposed. The genera and species are treated as synonyms and an emended diagnosis is given for Tranvikium polygonale, incorporating this whole morphological plexus. The possible purposes of the structures exhibited and the likely affinity of T. polygonale to various groups of algae are discussed. The emendation of Ampullula by Brocke (1997) is rejected and the genus Stelomorpha Yin, 1994 retained, with an emended diagnosis. The new combination Stelomorpha princeps (Brocke, 1997) Uutela and Sarjeant is proposed.     

The Biochemical of Tetradium,Euodia and Melicope and their significance in the Rutaceae

From the stem and root barks of Tetradium glabrifolium (Rutaceae) benzophenanthridine alkaloids have been isolated together with furoquinoline alkaloids, coumarins and limonoids. The occurrence of the l-benzyltetrahydroisoquinolinederived benzophenanthridines adds Tetradium to the small group of rutaceous genera (Fagaropsis, Phellodendron, Toddalia, Zanthoxylum) known to produce alkaloids of this type. These findings support Hartley's decision to reassign taxa from Euodia (sensu Engler) into the three genera Tetradium, Euodia s. s. and Melicope and his contention that Tetradium is closely allied to Zanthoxylum and Phellodendron, with which it shares several unusual chemical characters. Hartley's re-alignment of Tetradium, which cuts across Engler's sub-families Rutoideae and Toddalioideae, is therefore sustained by the known distribution of secondary metabolites, whilst available information suggests a wide disparity between the chemical profiles of Tetradium and Melicope. The chemosystematic significance of the addition of Tetradium to the 1-benzyltetrahydroisoquinoline producing genera and the potential of these taxa to have acted as a starting point for biochemical evolution within the Rutaceae is discussed.     

Molecular phylogenetic evidence supports a new family of octocorals and a new genus of Alcyoniidae (Octocorallia,Alcyonacea)

Molecular phylogenetic evidence indicates that the octocoral family Alcyoniidae is highly polyphyletic, with genera distributed across Octocorallia in more than 10 separate clades. Most alcyoniid taxa belong to the large and poorly resolved Holaxonia–Alcyoniina clade of octocorals, but members of at least four genera of Alcyoniidae fall outside of that group. As a first step towards revision of the family, we describe a new genus, Parasphaerasclera gen. n., and family, Parasphaerascleridae fam. n., of Alcyonacea to accommodate species of Eleutherobia Pütter, 1900 and Alcyonium Linnaeus, 1758 that have digitiform to digitate or lobate growth forms, completely lack sclerites in the polyps, and have radiates or spheroidal sclerites in the colony surface and interior. Parasphaerascleridae fam. n. constitutes a well-supported clade that is phylogenetically distinct from all other octocoral taxa. We also describe a new genus of Alcyoniidae, Sphaerasclera gen. n., for a species of Eleutherobia with a unique capitate growth form. Sphaerasclera gen. n. is a member of the Anthomastus–Corallium clade of octocorals, but is morphologically and genetically distinct from Anthomastus Verrill, 1878 and Paraminabea Williams & Alderslade, 1999, two similar but dimorphic genera of Alcyoniidae that are its sister taxa. In addition, we have re-assigned two species of Eleutherobia that have clavate to capitate growth forms, polyp sclerites arranged to form a collaret and points, and spindles in the colony interior to Alcyonium, a move that is supported by both morphological and molecular phylogenetic evidence.