The internal-brooding apparatus in the bryozoan genus Cauloramphus (Cheilostomata: Calloporidae) and its inferred homology to ovicells

We studied by SEM the external morphology of the ooecium in eight bryozoans of the genus Cauloramphus (Cheilostomata, Calloporidae): C. spinifer, C. variegatus, C. magnus, C. multiavicularia, C. tortilis, C. cryptoarmatus, C. niger, and C. multispinosus, and by sectioning and light microscopy the anatomy of the brooding apparatus of C. spinifer, C. cryptoarmatus, and C. niger. These species all have a brood sac, formed by invagination of the non-calcified distal body wall of the maternal zooid, located in the distal half of the maternal (egg-producing) autozooid, and a vestigial, maternally budded kenozooidal ooecium. The brood sac comprises a main chamber and a long passage (neck) opening externally independently of the introvert. The non-calcified portion of the maternal distal wall between the neck and tip of the zooidal operculum is involved in closing and opening the brood sac, and contains both musculature and a reduced sclerite that suggest homology with the ooecial vesicle of a hyperstomial ovicell. We interpret the brooding apparatus in Cauloramphus as a highly modified form of cheilostome hyperstomial ovicell, as both types share 1) a brood chamber bounded by 2) the ooecium and 3) a component of the distal wall of the maternal zooid. We discuss Cauloramphus as a hypothetical penultimate stage in ovicell reduction in calloporid bryozoans. We suggest that the internal-brooding genus Gontarella, of uncertain taxonomic affinities, is actually a calloporid and represents the ultimate stage in which no trace of the ooecium remains. Internal brooding apparently evolved several times independently within the Calloporidae.     

Brood chambers constructed from spines in fossil and Recent cheilostome bryozoans

Most cheilostome bryozoans brood their larvae in skeletal structures called ovicells which, in evolutionary terms, were derived from spines. Ovicells in the great majority of fossil and Recent cheilostomes, however, have lost all or most traces of their spinose origin. Here we review the occurrence of spinose (including costate) brood chambers in cheilostomes, investigating in detail 32 species belonging to ten genera among five families (Calloporidae, Monoporellidae, Macroporidae, Cribrilinidae and Tendridae). Spinose ovicells are moderately common in the Upper Cretaceous, where they are recorded in 28 species, and also occur in one Palaeocene, seven Eocene‐Miocene and 11 Recent species. The most primitive cheilostome ovicells occur in mid‐Cretaceous calloporids in which a group of mural spines belonging to the distal zooid were apparently bent towards the maternal zooid to form a cage‐like structure for reception of the embryo. The bases of these spines were initially aligned in a distally concave row that later became straight, distally convex and finally horseshoe‐shaped, affording progressively better protection for the developing embryo. We suggest that primitive monoporellids inherited from calloporid ancestors a distally concave arrangement of ovicell spine bases, while cribrilinids inherited a horseshoe‐shaped arrangement. Important trends that can be recognized in early ovicell evolution include: (1) loss of basal spine articulation; (2) spine flattening; (3) closure of the gaps between spines; (4) reduction in spine number (through loss or fusion), and (5) development of a concave ovicell floor. The conventional ‘unipartite’ ovicells found in the majority of cheilostomes may have originated either by spine fusion, as seems likely in some cribrilinids, or through a progressive loss of spines via an intermediate stage, seen in some calloporids and in two monoporellids, where the ovicell comprises a large pair of flattened spines. The spinose ovicells of some monoporellids and macroporids subsequently evolved investments of hypostegal coelom that allowed secretion of a surface layer of cryptocystal calcification. Acanthostegous brood chambers characteristic of Tendridae apparently provide an example of independent evolution of spinose brooding structures. © 2005 The Natural History Museum, London, Zoological Journal of the Linnean Society, 2005, 144 , 317?361.     

Comparative anatomy of internal incubational sacs in cupuladriid bryozoans and the evolution of brooding in free‐living cheilostomes

Numerous gross morphological attributes are shared among unrelated free‐living bryozoans revealing convergent evolution associated with functional demands of living on soft sediments. Here, we show that the reproductive structures across free‐living groups evolved convergently. The most prominent convergent traits are the collective reduction of external brood chambers (ovicells) and the acquisition of internal brooding. Anatomical studies of four species from the cheilostome genera Cupuladria and Discoporella (Cupuladriidae) show that these species incubate their embryos in internal brooding sacs located in the coelom of the maternal nonpolymorphic autozooids. This sac consists of a main chamber and a narrow neck communicating to the vestibulum. The distal wall of the vestibulum possesses a cuticular thickening, which may further isolate the brood cavity. The presence of this character in all four species strongly supports grouping Cupuladria and Discoporella in one taxon. Further evidence suggests that the Cupuladriidae may be nested within the Calloporidae. Based on the structure of brooding organs, two scenarios are proposed to explain the evolution of the internal brooding in cupuladriids. The evolution of brood chambers and their origin in other free‐living cheilostomes is discussed. Unlike the vast majority of Neocheilostomina, almost all free‐living cheilostomes possess nonprominent chambers for embryonic incubation, either endozooidal and immersed ovicells or internal brooding sacs, supporting the idea that internal embryonic incubation is derived. We speculate that prominent skeletal brood chambers are disadvantageous to a free‐living mode of life that demands easy movement through sediment in instable sea‐floor settings. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.     

Ovicell structure in Callopora dumerilii and C. lineata (Bryozoa: Cheilostomatida)

Anatomical and SEM-studies of the brood-chambers (ovicells) in two bryozoans (Callopora dumerilii and C. lineata) were undertaken to resolve a long-term controversy existing in the literature about the origin of the ovicells. In contrast with the interpretation of Silén (1945 ), both species investigated possess hyperstomial ovicells with the ooecium formed by the distal (daughter) zooid. The ooecial coelomic cavity communicates with the zooidal coelom through a pore-like canal or canals remaining after the closure of an arch-shaped slit. The slit forms during ovicellogenesis. The communication canals are normally plugged by epithelial cells, however incompletely closed canals were also found in Callopora lineata. SEM-studies of noncleaned, air-dried specimens showed a relationship between membranous and calcified parts during early ovicellogenesis. It starts from a transverse wall as the calcification of the proximal part of the daughter zooid frontal wall, and has the shape of two flat rounded plates. There are no knobs or any other outgrowths. Conditions and phenomenology of hyperstomial ovicell formation are discussed.     

Systematics of Upper Cretaceous calloporid bryozoans with primitive spinose ovicells

The majority of fossil and Recent cheilostome bryozoans brood their larvae in ovicells. These double-walled, hood-like skeletal structures are thought to have arisen through modification of spines belonging to the zooid distal of the maternal zooid. Support for this hypothesis comes from the existence of ovicells constructed of multiple spines in a few Upper Cretaceous species belonging to two groups, microporids and cribrimorphs. Here we report the discovery of similar multispinose ovicells in a third group, calloporids, which are closely related to primitive cheilostomes that do not brood their larvae. The genus Distelopora Lang, 1915 from the Cenomanian ('Chalk Marl') of Cambridge is taken out of synonymy and shown to comprise the type species ( D. bipilata ) and two new species ( D. langi and D. spinifera ) of multiserial calloporids. Between 5 and 15 spine bases are arranged in a crescent on the gymnocyst of the zooid distal of each maternal (egg-producing) zooid in Distelopora . This indicates the presence of an ovicell formed by a cage of basally articulated spines. Similar ovicells represented by 18–19 spine bases occur in a uniserial calloporid from the German Campanian Allantopora krauseae Voigt and Schneemilch, 1986, which is made the type species of the new genus Unidistelopora . Another calloporid from the Cambridge Cenomanian has ovicells constructed by two claw-like, flattened, non-articulated and laterally juxtaposed spines. Described as Gilbertopora larwoodi gen. et sp. nov., this multiserial species provides a link between Distelopora and more typical cheilostome ovicells. The spines forming primitive ovicells provide a good example of exaptations, co-opted from their original function protecting the polypide of the distal zooid.     

Comparative Studies of Ovicell Anatomy and Reproductive Patterns in Cribrilina annulata and Celleporella hyalina (Bryozoa: Cheilostomatida)

Investigations of the common boreal-arctic cheilostomate bryozoans Cribrilina annulata and Celleporella hyalina have shown that the two species possess similar ovicell structures and reproductive patterns. Both species are characterized by frontal dwarf ovicellate zooids, that are female autozooidal polymorphs in C. hyalina and simultaneous hermaphroditic autozooids in C. annulata. The latter species in addition has ovicellate autozooids of the usual type. Each ovicell is formed from a maternal zooid only, and its cavity is lined by the outer hemispherical fold (ooecium) and the distal zooidal wall. The coelomic cavity of the ooecium is separated from the body cavity of the maternal zooid by a transverse wall with simple pores. Each pore is closed by a cell plug, and the ooecia may be considered as kenozooids. Each oocyte is accompanied by a single nurse cell that degenerates after ovulation. The eggs are macrolecithal in C. annulata and microlecithal in C. hyalina, and the former species is a non-placental brooder whereas the latter forms a placenta. Fertilization is precocious. Possible mechanisms of sperm entry as well as oviposition are discussed. The literature concerning ovicell structure and development in cheilostomates is analysed. It is proposed that the brood chamber of cribrimorphs evolved by a fusion of costae and a reduction of the daughter zooid in ancestral forms. © 1998 The Royal Swedish Academy of Sciences. Published by Elsevier Science Ltd. All rights reserved     

Comparative anatomical study of internal brooding in three anascan bryozoans (Cheilostomata) and its taxonomic and evolutionary implications

The anatomical structure of internal sacs for embryonic incubation was studied using SEM and light microscopy in three cheilostome bryozoans-Nematoflustra flagellata (Waters,1904), Gontarella sp., and Biflustra perfragilis MacGillivray, 1881. In all these species the brood sac is located in the distal half of the maternal (egg-producing) autozooid, being a conspicuous invagination of the body wall. It consists of the main chamber and a passage (neck) to the outside that opens independently of the introvert. There are several groups of muscles attached to the thin walls of the brood sac and possibly expanding it during oviposition and larval release. Polypide recycling begins after oviposition in Gontarella sp., and the new polypide bud is formed by the beginning of incubation. Similarly, polypides in brooding zooids degenerate in N. flagellata and, sometimes, in B. perfragilis. In the evolution of brood chambers in the Cheilostomata, such internal sacs for embryonic incubation are considered a final step, being the result of immersion of the brooding cavity into the maternal zooid and reduction of the protecting fold (ooecium). Possible reasons for this transformation are discussed, and the hypothesis of Santagata and Banta (Santagata and Banta1996) that internal brooding evolved prior to incubation in ovicells is rejected.     

Stipa×brozhiana (Poaceae) nothosp. nov. from the western Pamir Alai Mts (middle Asia) and taxonomical notes on Stipa×tzvelevii

Stipa ×brozhiana M. Nobis nothosp. nov. (Poaceae) is described and illustrated. The taxon belongs to sect. Smirnovia Tzvel. and originated from the hybridization of species belonging to sect. Smirnovia and Barbatae Junge. Stipa ×brozhiana is morphologically close to Stipa lipskyi Roshev., but is easily distinguished by its much shorter hairs on the seta, thinner, uni‐ or indistinctly bigeniculate awns, differently shaped callus and longer ligules of vegetative shoots. Characters distinguishing S. ×brozhiana from the parental species and other similar hybrid taxa belonging to sect. Smirnovia and occurring in the Pamir Alai Mts are discussed. In addition, the taxonomical status of S. ×tzvelevii Ikonn. pro sp., another taxon that has originated from hybridization between species belonging to sect. Smirnovia and Barbatae, is discussed. The taxon was originally described as a distinct species, but is now considered to be the hybrid S. caucasica×S. orientalis. The main characters distinguishing S. ×tzvelevii from parental species are given.     

A coded checklist and ecological indicator values of freshwater diatoms from The Netherlands

This first comprehensive checklist of the diatoms from fresh and weakly brackish water in The Netherlands comprises 948 taxa, belonging to 776 species in 56 genera. The generaNavicula, which has a very wide ecological amplitude, andNitzschia, which has many pollution tolerant species, are most numerous. Each taxon is identified with a unique eight-letter code, to facilitate computer processing of data. Ecological indicator values for pH, salinity, nitrogen uptake metabolism, oxygen, saprobity, trophic state and moisture are presented.     

Ultrastructure and Development of the Ooecial Walls in Some Calloporid Bryozoans (Gymnolaemata: Cheilostomata)

In the brood chambers (ovicells) of six calloporid cheilostomes studied each skeletal wall consists of four calcified layers: (1) a very thin superficial layer of planar spherulitic crystallites, (2) an upper (outer) layer with wall-perpendicular prismatic ultrastructure, (3) an intermediate lamellar layer, and (4) a lower (inner) wall-perpendicular prismatic layer. Comparative studies of both the ovicell wall ultrastructure and early ovicell formation showed a hypothetical opportunity for evolving complex (multilayered) skeletal walls by fusion of the initially separated gymnocystal and cryptocystal calcifications in Cheilostomata. In two species studied, a bilobate pattern in the final stage of the formation of the ooecial roof was encountered in specimens with the cuticle preserved. A possible explanation to this finding is discussed – the bilobate pattern is suggestive of the hypothetical origin of the brood chamber from (1) two flattened spines, or (2) reduction in spine number of an originally multispinous ovicell.     

A new species of <Emphasis Type="Italic">Almeidea</Emphasis> (Galipeinae,Galipeeae, Rutaceae) from Eastern Brazil

A new species of Almeidea (Rutaceae) belonging to the neotropical tribe Galipeeae (subtribe Galipeinae) is described and illustrated. This new species, Almeidea albiflora, is known so far only from a few collections made in small disturbed forest remnants in the vicinity of Cachoeiro de Itapemirim, in the state of Espírito Santo, and by a single collection from northern Rio de Janeiro state, both in the domain of the Atlantic Forest, Eastern Brazil. Diagnostic features, like white petals, sericeous ovary and distal secondary axes as long as the proximal ones are identified. Pollen morphology is also described, and brief discussions of the relationships of the new taxon to other species of Almeidea, as well as comments on its conservation status, are provided.     

A phylogenetic assessment of the branchiobdellidan family Branchiobdellidae (Annelida,Clitellata) using spermatological and somatic characters

The spermatozoa of six species belonging to the branchiobdellidan family Branchiobdellidae (i.e. Xironogiton victoriensis, Cirrodrilus kawamurai, Ankyrodrilus legaeus, Xironodrilus formosus, Branchiobdella kobayashii, Branchiobdella orientalis) were studied and compared to the other sperma‐tozoa already described in the group. A parsimony analysis was performed on the spermatozoal data of the species examined, as well as on their somatic characters. The results of the two analyses were contrasted and a further parsimony analysis was run on the matrix comprising both sets of characters. The study of sperm ultrastructure confirmed the genera recognized with traditional somatic characters and the monophyly of the branchiobdellidans. Xironodrilus was proved to be the sister species of Ankyrodrilus and its inclusion into the family Branchiobdellidae was supported. Evolutionary hypotheses on intergeneric differences in the family consistent with its biogeography can be suggested by the cladograms: Xironogiton is an early offshoot of branchiobdellidan lineage migrating to North America and probably radiating only in recent times; Branchiobdella kobayashii has a spermatozoon completely different from that of the other species of the genus, thus suggesting a complex story for this widespread taxon with a disjunct distribution.     

A NEW LOOK AT AN ANCIENT ORDER: GENERIC REVISION OF THE BANGIALES (RHODOPHYTA)1

The red algal order Bangiales has been revised as a result of detailed regional studies and the development of expert local knowledge of Bangiales floras, followed by collaborative global analyses based on wide taxon sampling and molecular analyses. Combined analyses of the nuclear SSU rRNA gene and the plastid RUBISCO LSU (rbcL) gene for 157 Bangiales taxa have been conducted. Fifteen genera of Bangiales, seven filamentous and eight foliose, are recognized. This classification includes five newly described and two resurrected genera. This revision constitutes a major change in understanding relationships and evolution in this order. The genus Porphyra is now restricted to five described species and a number of undescribed species. Other foliose taxa previously placed in Porphyra are now recognized to belong to the genera Boreophyllum gen. nov., Clymene gen. nov., Fuscifolium gen. nov., Lysithea gen. nov., Miuraea gen. nov., Pyropia, and Wildemania. Four of the seven filamentous genera recognized in our analyses already have generic names (Bangia, Dione, Minerva, and Pseudobangia), and are all currently monotypic. The unnamed filamentous genera are clearly composed of multiple species, and few of these species have names. Further research is required: the genus to which the marine taxon Bangia fuscopurpurea belongs is not known, and there are also a large number of species previously described as Porphyra for which nuclear SSU ribosomal RNA (nrSSU) or rbcL sequence data should be obtained so that they can be assigned to the appropriate genus.     

Molecular support for morphology‐based family‐rank taxa: The contrasting cases of two families of Proseriata (Platyhelminthes)

Representatives of the Meidiamidae and Otomesostomidae (Platyhelminthes: Proseriata) are seldom encountered, and the monophyly and phylogenetic relationships of these families have never been assessed on molecular basis. Here, we present the first exhaustive molecular study of Proseriata at the family level, including species belonging to the genera Meidiama and Yorknia (Meidiamidae), and Otomesostoma auditivum (Otomesostomidae), using 18S and 28S genes as markers. We performed phylogenetic analyses (Maximum Likelihood [ML] and Bayesian Inference [BI] methods) and species delimitation methods (Single/Multiple Threshold‐Generalized Mixed Yule Coalescent [ST/MT‐GMYC] and Poisson Tree Processes [PTP/bPTP]). The taxon Meidiamidae was not supported, since the type species (Meidiama lutheri) and Meidiama etrusca sp. n. are nested within the Archimonocelididae, formerly restricted to specialized cnidarian feeders. Species belonging to the genus Yorknia resulted genetically well separated from species of Meidiama and from the rest of Archimonocelididae. The new family‐level taxon Yorkniidae fam. n. is thus here introduced, to include the type species of Yorknia (Yorknia aprostatica), and six new species, five of which are formally described here. Otomesostoma auditivum, representative of Otomesostomidae, the only exclusively freshwater taxon of the Proseriata, is the sister taxon of the predominantly marine Apingospermata. This result is not conflictual with the family level attributed to Otomesostomidae on morphological grounds, but it raises speculations on the marine versus freshwater origin of Apingospermata.     

Studies on the mycoflora associated with sugarcane factory waste and pollution of River Nile in upper Egypt

Sixty-nine species and four varieties that belong to 28 genera of terrestial fungi were recovered from polluted and non-polluted water and mud samples on glucose and cellulose-Czapek's agar at 28°C. The most common species from the two substrates on the two types of media were Aspergillus flavus, A. fumigatus, A.niger, Cladosporium cladosporioides, Fusarium oxysporum, Mycosphaerella tassiana and Penicillium chrysogenum. Twenty-six species belonging to 14 genera were isolated from polluted (26 species and 14 genera) and non-polluted (17species and 10 genera) mud samples on Sabouraud's dextrose agar at 28°C. The most prevalent species were Acremonium retiulum, Alternaria alternata, Aspergillus flavus, Aphanoascus fulvescens, A. terreus, Aphanoascus sp., Penicillium funiculosum and Stachybotrys chartarum.     

Ichnologic Note A New Ichnospecies of Cardioichnus from the Cretaceous (Albian) of New Mexico

A new ichnospecies of Cardioichnus, Cardioichnus biloba isp. nov., is described and documented from shallow marine strata of Cretaceous (Late Albian) age in southern New Mexico, USA. It is a heart-shaped resting trace which, unlike all other ichnospecies of Cardioichnus, is epichnial and increases in width to a bilobate trace, often with a raised anterior terminus. Only the posterior end of this trace is associated with Bichordites burrows, and the anterior end is bilobate and undisturbed. This represents a resting position which differs from other known species of this cubichnium, which are hypichnial and subquadrate in symmetry. The tracemaker is a spatangoid echinoid, most likely Heteraster d'Orbigny, 1853.     

Colony Growth Pattern in Electra pilosa (Linnaeus) and Comparable Encrusting Cheilostome Bryozoans

Colony growth pattern is described in E. pilosa, an abundant cheilostome bryozoan commonly found as an epiphyte of Laminaria. Each zooid has 4 potential budding loci—one distal, two lateral and one proximal. The ancestrula buds daughter zooids from all of these loci; the two lateral buds appear first, followed by the distal bud and, after a long delay, the proximal bud. The laterally budded zooids curve inwards as they grow to form a triad with their distally budded sibling zooid. ‘Mature’ multiserial colonies growing on flat substrata consist of a series of radially diverging sectors. Each sector has an axis, generally of 3 parallel rows of zooids, flanked by wings consisting of rows of zooids originating as lateral buds from the section axis which infills the area between the axes. Occasional colonies occur with uniserial or semiuniserial growth patterns. These resemble colonies of the obligatory uniserial species Pyripora catenularia and poorly fed colonies of the related Conopeum tenuissimum, which is normally multiserial like E. pilosa. The ‘composite multiserial’ colonies of E. pilosa differ in several respects from ‘unitary multiserial’ colonies characteristic of most sheet-like cheilostomes, including the well-known Membranipora membranacea. Composite and unitary multiserial growth patterns may have evolved independently from uniserial ancestors.     

New considerations on the phylogeny of cyrtophorian ciliates (Protozoa,Ciliophora): expanded sampling to understand their evolutionary relationships

To rationalize the confusing relationships among the cyrtophorian ciliates, we expanded the taxon sampling by sequencing the small subunit ribosomal RNA (SSU rRNA) gene of representatives of 12 genera (20 species, 23 new sequences). The SSU rRNA sequences of Spirodysteria, Agnathodysteria, Brooklynella and Odontochlamys are reported for the first time. Phylogenetic trees were constructed, and secondary structures of variable region 4 (V4) of all genera for which SSU rRNA gene sequence data are available were predicted. The results indicate that (i) Brooklynella is likely an intermediate taxon between Dysteriidae and Hartmannulidae; (ii) the genus Dysteria is paraphyletic with Spirodysteria and Mirodysteria nested within it; (iii) the genus Agnathodysteria is well separated from Dysteria based on both molecular and morphological data; and (iv) Trithigmostoma is a basal genus of Chilodonellidae, based on both the morphological and molecular data.     

Molecular phylogeny of the ant tribe Myrmicini (Hymenoptera: Formicidae)

The interrelationships within ant subfamilies remain elusive, despite the recent establishment of the phylogeny of the major ant lineages. The tribe Myrmicini belongs to the subfamily Myrmicinae, and groups morphologically unspecialized genera. Previous research has struggled with defining Myrmicini, leading to considerable taxonomic instability. Earlier molecular phylogenetic studies have suggested the nonmonophyly of Myrmicini, but were based on limited taxon sampling. We investigated the composition of Myrmicini with phylogenetic analyses of an enlarged set of taxa, using DNA sequences of eight gene fragments taken from 37 representatives of six of the seven genera (Eutetramorium, Huberia, Hylomyrma, Manica, Myrmica, and Pogonomyrmex), and eight outgroups. Our results demonstrate the invalidity of Myrmicini as currently defined. We recovered sister‐group relationships between the genera Myrmica and Manica, and between Pogonomyrmex and Hylomyrma. This study illustrates that to understand the phylogeny of over 6000 myrmicine species, comprehensive taxon sampling and DNA sequencing are an absolute requisite. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 482–495.