Single Row Of Cells Research Articles

Distribution pattern of floor plate neurons in zebrafish.

The floor plate (FP) is a critical signaling center for the development of neural tube and body axis, and is localized at the ventral midline of the neural tube. Multiple types of neurons are present in the floor plate, while the distribution pattern of these neuronal cells remains unclear. By using transgenic zebrafish lines that specifically label different neuronal cells, we investigated the distribution pattern of these neurons in the floor plate region. Our results showed that foxj1a, sox2, clusterin and gfap genes were expressed in the medial floor plate (MFP), consisting of a single row of cells. The cerebrospinal fluid-contacting neurons (CSF-cNs), also named as Kolmer-Agduhr interneurons (KA' and KA" neurons), were located on the lateral sides of MFP. The foxj1a and pkd2l1 genes were expressed in the KA" neurons, which were located to the ventral terminal gap of wedge-shaped MFP cells. The neighboring KA" neurons were separated by neurons expressing Gfap, Olig2 or Sox2. In contrast, the KA' neurons were positive for Foxj1a +/Pkd2l1+/Olig2+, and were localized to the dorsal side of KA" neurons. Similarly, the Sox2 or Olig2 expressing neurons were intermingled with KA' neurons along the anterior-posterior axis in these regions. Further pharmaceutical treatment demonstrated that interference of Notch signaling resulted in the abnormal distribution of floor plate neurons together with strong dorsal body curvature at 3 days post fertilization in the zebrafish larvae. Our data showed the gene expression patterns and relative positions of the floor plate neurons; and suggested a potential role of Notch signaling during floor plate development.

The first ‘Megapodagrionidae’ (Odonata, Zygoptera) from the Lower Cretaceous of Democratic People's Republic of Korea

A new fossil genus and species, Phyonganpodagrion ryonsangae sp. nov. (‘Megapodagrionidae’) is described from the third member, the Sinuiju Formation, Barremian–Aptian, Lower Cretaceous, Ryonsang-dong, Sinuiju City, North Phyongan Province, DPRK. The new species distinctly differs from Cretapodagrion sibelleae Huang et al., 2018 in postnodal area with only 17 postnodal crossveins; a single row of cells (partly with two rows of cells) between IR1 and RP1; distal side of discoidal cell not oblique; base of RP3/4 well basad of subnodus; base of IR2 aligned with subnodus.

Evolution of Developmental Programs for the Midline Structures in Chordates: Insights From Gene Regulation in the Floor Plate and Hypochord Homologues of Ciona Embryos.

In vertebrate embryos, dorsal midline tissues, including the notochord, the prechordal plate, and the floor plate, play important roles in patterning of the central nervous system, somites, and endodermal tissues by producing extracellular signaling molecules, such as Sonic hedgehog (Shh). In Ciona, hedgehog.b, one of the two hedgehog genes, is expressed in the floor plate of the embryonic neural tube, while none of the hedgehog genes are expressed in the notochord. We have identified a cis-regulatory region of hedgehog.b that was sufficient to drive a reporter gene expression in the floor plate. The hedgehog.b cis-regulatory region also drove ectopic expression of the reporter gene in the endodermal strand, suggesting that the floor plate and the endodermal strand share a part of their gene regulatory programs. The endodermal strand occupies the same topographic position of the embryo as does the vertebrate hypochord, which consists of a row of single cells lined up immediately ventral to the notochord. The hypochord shares expression of several genes with the floor plate, including Shh and FoxA, and play a role in dorsal aorta development. Whole-embryo single-cell transcriptome analysis identified a number of genes specifically expressed in both the floor plate and the endodermal strand in Ciona tailbud embryos. A Ciona FoxA ortholog FoxA.a is shown to be a candidate transcriptional activator for the midline gene battery. The present findings suggest an ancient evolutionary origin of a common developmental program for the midline structures in Olfactores.

Learning from plant movements triggered by bulliform cells: the biomimetic cellular actuator.

Within the framework of a biomimetic top-down approach, our study started with the technical question of the development of a hinge-free and compliant actuator inspired by plant movements. One meaningful biological concept generator was the opening and closing movements of the leaf halves of grasses. Functional morphological investigations were carried out on the selected model plant Sesleria nitida. The results formed the basis for further clarifying the functional movement principle with a particular focus on the role of turgor changes in bulliform cells on kinetic amplification. All findings gained from the investigations of the biological model were incorporated into a finite-element analysis, as a prerequisite for the development of a pneumatic cellular actuator. The first prototype consisted of a row of single cells positioned on a plate. The cells were designed in such a way that the entire structure bent when the pneumatic pressure applied to each individual cell was increased. The pneumatic cellular actuator thus has the potential for applications on an architectural scale. It has subsequently been integrated into the midrib of the facade shading system Flectofold in which the bending of its midrib controls the hoisting of its wings.

Clinicopathological Characteristics of Well-differentiated Papillary Mesothelioma of The Peritoneum: A Single-institutional Experience of 12 Cases.

Well-differentiated papillary mesothelioma (WDPM) is histologically characterized by papillary architecture with fibrovascular cores, lined by bland mesothelial cells. We recently experienced a case of WDPM associated with multiple peritoneal inclusion cysts, which prompted us to initiate a comprehensive review of previously diagnosed WDPM cases. The clinicopathological characteristics and immunophenotype of 12 cases of peritoneal WDPM were investigated using a review of electronic medical records, pathological examination, and immunostaining. The patients' ages ranged from 23 to 75 years. No patient had endometriosis or a previous history of asbestos exposure. Ten tumors were detected incidentally during surgery for other causes. Most tumors appeared as a small, single nodule on the peritoneal surface, but in three cases, WDPM presented as multiple lesions. All but one patient had no symptoms. All the patients examined are still well without postoperative recurrence. Histologically, all cases demonstrated typical papillary architecture with fibrovascular cores. The mesothelial cells lining the papillae consisted mostly of single row of cells, although areas of proliferation to multiple layers were observed in a few cases. Their nuclei appeared bland, but two cases exhibited mild nuclear atypia and prominent nucleoli. Immunostaining revealed that the mesothelial cells were positive for D2-40, cytokeratin 5/6, cytokeratin 7, and Wilms' tumor 1. We herein demonstrated the clinicopathological characteristics of peritoneal WDPMs. WDPM has distinct pathological features. Although all cases we examined were uneventful after surgery, further surveillance is recommended since the biological behavior of WDPM is still uncertain.

Effects of Helicobacter pylori on the expression levels of GATA-3 and connexin 32 and the GJIC function in gastric epithelial cells and their association by promoter analysis.

The present study aimed to explore the effects of Helicobacter pylori (H. pylori) infection on the expression of transcription factor GATA binding protein 3 (GATA-3) and connexin 32 (Cx32) in cultured gastric mucosa cells, and their association with each other. GES-1 cells were co-cultured with East Asian type cytotoxin-associated gene A+ H. pylori in the H. pylori group, and without H. pylori culture in the control group. Additionally, Mongolian gerbils were gavaged with H. pylori, and later the gastric antrum tissues were collected. The GATA-3 and Cx32 mRNA and protein expression levels were detected by a reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. The scratch labeling fluorescent dye tracer (SLDT) technique was used to detect the gap junctional intercellular communication (GJIC) function. GATA-3 small interfering RNA (siRNA) was transfected into BGC823 cells and its effect on Cx32 expression levels was detected. The impact of GATA-3 on Cx32 promoter transcriptional activity was detected using a dual luciferase reporter assay. The results revealed that H. pylori infection increased GATA-3 expression and decreased Cx32 expression in GES-1 cells and in animal gastric tissues compared with their respective controls, whilst in BGC823 cells, GATA-3 siRNA increased Cx32 expression compared with the control. In the SLDT experiment of GES-1 cells with H. pylori infection, the fluorescent dye was primarily limited to a single cell row close to the scratch, and only a limited amount of dye passing to the second cell row, indicating that the GJIC function was substantially reduced or absent compared with the control group, where the fluorescence dye transferred to the neighboring cells of 3–4 rows, indicating a stronger GJIC function comparatively. GATA-3 inhibited the expression of the luciferase reporter gene, compared with the controls, suggesting that GATA-3 inhibited the expression of Cx32 by binding to Cx32 promoter sites. These results indicated that H. pylori-increased GATA-3 expression, which downregulated Cx32 expression, may serve an important function in gastric carcinogenesis, and GATA-3 siRNA may serve a function in the prevention and treatment of gastric cancer.

Ontogenetic development and functioning of the anterior end of Cossura pygodactylata Jones, 1956 (Annelida: Cossuridae)

Juvenile and adult Cossura pygodactylata Jones 1956 from the White Sea were studied using confocal laser scanning microscopy, light microscopy, scanning and transmission electron microscopy. Transformations of the anterior musculature and digestive tract during ontogenesis were investigated. The early juveniles were shown to be lecithotrophic; their pharyngeal cavities were not connected to the intestines, which contained yolk granules. The juveniles bore prototrochs, which are used for movement, although juveniles had parapodial musculature similar to that of the adults. The juveniles presumably inhabit the upper semi-liquid layer of the silt. The muscles of the prostomium and circumbuccal complex change dramatically during ontogenesis. The ultrastructure of the buccal tentacles is redescribed. The tentacles consist of outer ciliated epithelial cells and an inner cylinder formed by epithelio-muscle cells. The blood sinus is situated between the central cylinder and the epithelium. Both juveniles and adults have developed circulatory systems. The whole dorsal vessel forms the heart with walls that consist of cells with circular cross-striated muscular fibres. The inner lumen is occluded by the heart body which is formed by a single row of cells that are tightly pressed together and connected by adherens junctions along their anterior and posterior surfaces. They contain granules and vesicles and bear numerous processes on the outer surface. The heart body most likely has a secretory haemopoetic function. A hypothetical mechanism of protraction and retraction of the buccal tentacles is suggested, and the participation of muscle contraction and relaxation in these movements is described. It is proposed that the protraction of the tentacles is provided by cell rigidity and increases in the blood volume in the tentacles blood sinuses. The development of the circulatory system is likely related to the need to keep the tentacles exposed during feeding while the anterior part of the body cavity is filled with muscle cell processes and there is no coelomic liquid flow. The proposed mechanism of feeding inside the sediment contrasts with that of surface feeding suggested by Tzetlin (Mem Mus Natl Hist Nat 162:137–143, 1994).

New species of <i>Grammolingia</i> Ren, 2002 from the Middle Jurassic of Inner Mongolia, China (Neuroptera: Grammolingiidae)

Three new species, <i>Grammolingia uniserialis</i> n. sp., <i>Grammolingia binervis</i> n. sp., and <i>Grammolingia sticta</i> n. sp. are described from the Jiulongshan Formation of northeastern China. <i>G. uniserialis</i> n. sp. exhibits a single row of cells in the costal area almost along the entire wing length except the basal part, which is rare in the family and firstly found in this genus. <i>G. binervis</i> n. sp. and <i>G. sticta</i> n. sp. add two new patterns of wing markings to the family. A key to the species of <i>Grammolingia</i> Ren, 2002 is provided. All types of wing markings present in this family are classified. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201300008" target="_blank">10.1002/mmng.201300008</a>

New species ofGrammolingiaRen, 2002 from the Middle Jurassic of Inner Mongolia, China (Neuroptera: Grammolingiidae)

Abstract. Three new species, Grammolingia uniserialis n. sp., Grammolingia binervis n. sp., and Grammolingia sticta n. sp. are described from the Jiulongshan Formation of northeastern China. G. uniserialis n. sp. exhibits a single row of cells in the costal area almost along the entire wing length except the basal part, which is rare in the family and firstly found in this genus. G. binervis n. sp. and G. sticta n. sp. add two new patterns of wing markings to the family. A key to the species of Grammolingia Ren, 2002 is provided. All types of wing markings present in this family are classified. doi: 10.1002/mmng.201300008

What is a segment?

Animals have been described as segmented for more than 2,000 years, yet a precise definition of segmentation remains elusive. Here we give the history of the definition of segmentation, followed by a discussion on current controversies in defining a segment. While there is a general consensus that segmentation involves the repetition of units along the anterior-posterior (a-p) axis, long-running debates exist over whether a segment can be composed of only one tissue layer, whether the most anterior region of the arthropod head is considered segmented, and whether and how the vertebrate head is segmented. Additionally, we discuss whether a segment can be composed of a single cell in a column of cells, or a single row of cells within a grid of cells. We suggest that ‘segmentation’ be used in its more general sense, the repetition of units with a-p polarity along the a-p axis, to prevent artificial classification of animals. We further suggest that this general definition be combined with an exact description of what is being studied, as well as a clearly stated hypothesis concerning the specific nature of the potential homology of structures. These suggestions should facilitate dialogue among scientists who study vastly differing segmental structures.

Pharmacognostical and physicochemical investigation of the leaf of Calamintha officinalis moench

ObjectiveTo study sailent diagnostic pharmacognostical characters of the leaves of Calamintha officinalis Moench along with their phytochemical analysis, physicochemical parameters, fluorescence analysis of leaf powder and HPTLC study. MethodsFresh leaf and dried powder sample of leaf were studied macro-morphologically and microscopically. Preliminary phytochemical investigation of leaf for the standardization was performed. HPTLC analysis of ethanolic extract was performed using solvent system benzene: methanol in the ratio (9:1). ResultEpidermis of leaf was found to be formed of a single row of cells, those of the upper epidermis being larger than those of the lower epidermis and uniseriate non-glandular and glandular trichomes were observed. Mesophyll was heterogeneous and asymmetric; two types of parenchyma was clearly differentiated; palisade and spongy. The upper one (palisade parenchyma) was formed of a single row of elongated cells. Abundant chloroplasts were observed. The lower, spongy parenchyma was formed of irregularly shaped cells with large intercellular spaces. Vascular tissue was found at the level of the spongy parenchyma. Prismatic shape of calcium oxlate crystals has been found. The preliminary phytochemical screening shows the presence of carbohydrate, flavonoids, steroid and triterpenes. HPTLC analysis of ethanolic extract showed eight peaks confirming the presence of eight compounds in the ethanolic extract of the leaves. ConclusionsThe pharmacognostical and phytochemical parameters are major reliable and inexpensive criteria for confirmation of the crude drugs. The present work therefore attempts to report various necessary standards for the leaf of Calamintha officinalis Moench.

Morphology of Foliar Trichomes of the Chinese Cork OakQuercus variabilisby Electron Microscopy and Three-Dimensional Surface Profiling

Morphology of foliar trichomes was analyzed in Quercus variabilis by electron microscopy and three-dimensional surface profiling. Leaves from suppressed or dominant sprouts of the oak species were collected after a forest fire to unravel the effects of the disturbance factor on sprouting of the oak species. Scanning electron microscopy revealed two types of trichomes depending on the leaf surface. The trichomes on the adaxial surface were branched and constricted, and possessed a single row of thin-walled cells with a collapsed morphology (glandular branched uniseriate trichomes). Meanwhile, the trichomes on the abaxial surface were star-shaped, unfused with each other, and had 6 to 10 rays (nonglandular simple stellate trichomes). An apparent proliferation of trichomes was evident on the adaxial surface of the dominant sprouts. Uniseriate trichomes could be discernable as an elevation from the surface by white light scanning interferometry. By transmission electron microscopy, thin and convoluted cell wall, degenerated cytoplasm, and a single row of cells were characteristic of the trichomes on the adaxial surface. The thick cell walls of the mature trichomes on the abaxial surface represented the nonglandular nature. This is the first report on the morphological and ultrastructural characterization of foliar trichomes of the oak species.

A NewCynepterisfrom the Upper Triassic of Arizona: Potential Implications for the Early Diversification of Schizaealean Ferns

Cynepteris bolichii is proposed as a new species of the monogeneric fern family Cynepteridaceae on the basis of a single, well‐articulated specimen from the Upper Triassic Chinle Formation in Petrified Forest National Park, Arizona. The specimen consists of an erect rhizome with at least eight attached fronds. As for the other three known Cynepteris species, C. bolichii pinnae exhibit reticulate venation and scattered, solitary, exindusiate sporangia on their abaxial surfaces. Each sporangium is ovoid to pyriform with a short, thick stalk and a complete, apical, caplike annulus consisting of a single row of cells surrounding a multicellular distal plate. These sporangial features are similar to those of several fossil and extant schizaealean ferns. Cynepteris bolichii differs from other Cynepteris species mainly in having once‐pinnate fronds with abundant, elongate hairs on the rachises and veins. Most recent estimates of fern phylogeny consider the Jurassic fossils Stachypteris, Klukiopsis, and Klukia as the oldest fossil representatives of the Schizaeales. It is here proposed that Cynepteris should be considered as a probable Late Triassic record of the order. Features such as reticulate venation, scattered sporangia, and lack of fertile/sterile frond dimorphism are rare and scattered among other fossil and extant ferns currently attributed to the Schizaeales, underscoring the importance of fossils for understanding the early divergence, ancestral morphology, and biogeography of ancient plants groups like the ferns.

FGF3 in the floor plate directs notochord convergent extension in theCionatadpole

Convergent extension (CE) is the narrowing and lengthening of an embryonic field along a defined axis. It underlies a variety of complex morphogenetic movements, such as mesoderm elongation and neural tube closure in vertebrate embryos. Convergent extension relies on the same intracellular molecular machinery that directs planar cell polarity (PCP) in epithelial tissues, including non-canonical Wnt signaling components. However, it is not known what signals coordinate CE movements across cell fields. In the simple chordate Ciona intestinalis, the notochord plate consists of just 40 cells, which undergo mediolateral convergence (intercalation) to form a single cell row. Here we present evidence that a localized source of FGF3 in the developing nerve cord directs notochord intercalation through non-MAPK signaling. A dominant-negative form of the Ciona FGF receptor suppresses the formation of polarized actin-rich protrusions in notochord cells, resulting in defective notochord intercalation. Inhibition of Ciona FGF3 activity results in similar defects, even though it is expressed in an adjacent tissue: the floor plate of the nerve cord. In Xenopus mesoderm explants, inhibiting FGF signaling perturbs CE and disrupts membrane localization of Dishevelled (Dsh), a key regulator of PCP and CE. We propose that FGF signaling coordinates CE movements by regulating PCP pathway components such as Dsh.

Myelin Vacuolation, Optic Neuropathy and Retinal Degeneration after Closantel Overdosage in Sheep and in a Goat

Toxicity of closantel, a halogenated salicylanilide anthelmintic, is described in 11 sheep and a goat, humanely killed 4-70 days after accidental overdosage. Status spongiosis of the cerebrum and cerebellum was present, its severity decreasing with time after treatment. Ultrastructurally, vacuoles in the cerebral white matter were seen to be intramyelinic due to splitting of myelin lamellae at the intraperiod lines, indicating myelin oedema. In the optic nerves, Wallerian degeneration and eventual fibrosis and atrophy of the nerves followed myelin vacuolation. Lesions in the optic nerves were particularly advanced in the intracanalicular portion, indicating a compressive neuropathy within the optic canal. Acute retinal lesions consisted of papilloedema, necrosis of the outer retinal layers (especially the photoreceptor layer), and retinal separation in tapetal and non-tapetal areas. In more chronic cases, the outer nuclear layer was diffusely attenuated and generally reduced to a single row of cells.

Keeping single minded Expression on the Straight and Narrow

Recent Developmental Cell papers by De Renzis et al. (2006) and Bardin and Schweisguth (2006) show that members of the Bearded family interact with Neuralized to regulate trafficking of the Notch ligand Delta. This allows precise control of Notch signaling and restriction of single minded expression to a single row of cells.

Are bacillary bands responsible for expulsion of Trichinella spiralis?

Newborn larvae, muscle larvae, intestinal larvae, and adults of Trichinella spiralis were examined by light, scanning and transmission electron microscopy for the presence of bacillary bands and pores of the gland cells. Vital staining of living adults disclosed that the bacillary bands, approximately 5 μm in width, begin at the cephalic end of the worms, on each side of the worm, as a row of single cells. The bands extend, gradually increasing in width, to the posterior end of the worms; and in the mid-body and posterior end of the worms they measure approximately 17 μm wide and accommodate at least two cells side by side. Each gland cell communicates with the outside of the worms through a 1.5–2 μm pore, containing dense material, in the cuticle. The pores constitute anatomic weak points of Trichinella since they can be can be targeted by the host's humoral immune responses and enzymatic attacks. The appearance of patent pores after the first intestinal molt correlates in time with the early expulsion of Trichinella from the intestine, suggesting that the bands may be the source of secreted metabolic or antigenic irritants that initiate, or contribute, to the expulsion mechanisms. Further studies to elucidate the functions of these organs would greatly increase our understanding of the biology of Trichinella and the mechanisms of expulsion.

IrreC/rst-mediated cell sorting duringDrosophilapupal eye development depends on proper localisation of DE-cadherin

Remodelling of tissues depends on the coordinated regulation of multiple cellular processes, such as cell-cell communication, differential cell adhesion and programmed cell death. During pupal development, interommatidial cells (IOCs) of the Drosophila eye initially form two or three cell rows between individual ommatidia, but then rearrange into a single row of cells. The surplus cells are eliminated by programmed cell death, and the definitive hexagonal array of cells is formed, which is the basis for the regular pattern of ommatidia visible in the adult eye. Here, we show that this cell-sorting process depends on the presence of a continuous belt of the homophilic cell adhesion protein DE-cadherin at the apical end of the IOCs. Elimination of this adhesion belt by mutations in shotgun, which encodes DE-cadherin, or its disruption by overexpression of DE-cadherin, the intracellular domain of Crumbs, or by a dominant version of the monomeric GTPase Rho1 prevents localisation of the transmembrane protein IrreC-rst to the border between primary pigment cells and IOCs. As a consequence, the IOCs are not properly sorted and supernumerary cells survive. During the sorting process, Notch-mediated signalling in IOCs acts downstream of DE-cadherin to restrict IrreC-rst to this border. The data are discussed in relation to the roles of selective cell adhesion and cell signalling during tissue reorganisation.

Zero‐order switches and developmental thresholds

Mol Syst Biol. 1: 2005.0031 A long‐standing problem in developmental biology, closely associated with pattern formation, is how continuous morphogen gradients are translated into sharp response borders that define clearcut territories in which cells express different sets of genes. To understand how gradients can generate thresholds, several mechanisms have been investigated over the years. Initially, most of these studies were of a theoretical nature, unrelated to any specific example based on solid molecular background. In an elegant study currently published in Molecular Systems Biology (Melen et al , 2005), blending experiment with theory, Shilo, Barkai and co‐workers address this question within the context of a well‐selected developmental system. They resort to computational systems biology to uncover the role of a phosphorylation–dephosphorylation cycle in generating a sharp boundary separating distinct developmental domains in the Drosophila embryo. The phenomenon considered underlies pattern formation in the Drosophila embryonic ventral ectoderm. There, a graded MAPK activation results from a graded activation of the EGF receptor, via the binding of its ligand Spitz secreted by a single row of cells positioned along the midline of the ventral ectoderm. Degradation of the transcriptional repressor Yan is triggered upon phosphorylation by MAPK. Melen et al show that the boundaries of Yan degradation on the two sides of the midline are extremely sharp. The Yan protein is absent from 1–2 cell rows on each side of the midline, whereas the adjacent rows display high levels of Yan comparable to those seen in most lateral cells (Figure 1). How the graded MAPK activation is converted into an all‐or‐none degradation switch of Yan is the topic of this study. Figure 1. (Top) Schematic representation of MAPK activity and total Yan level as a function of distance from midline of ventral ectoderm in the …

Phylogenetic Relationships of Haplolepideous Mosses (Dicranidae) Inferred from rps4 Gene Sequences

The haplolepideous mosses (Dicranidae) constitute a large group of ecologically and morphologically diverse species recognised primarily by having peristome teeth with a single row of cells on the dorsal surface. The reduction of sporophytes in numerous moss lineages renders circumscription of the Dicranidae problematic. Delimitation of genera and higher taxa within it has also been difficult. We analyse chloroplast-encoded rps4 gene sequences for 129 mosses, including representatives of nearly all the haplolepideous families and subfamilies, using parsimony, likelihood and Bayesian criteria. The data set includes 59 new sequences generated for this study. With the exception of Bryobartramia, which falls within the Encalyptaceae, the Dicranidae are resolved in all analyses as a monophyletic group including the extremely reduced Archidiales and Ephemeraceae. The monotypic Catoscopium, usually assigned to the Bryidae is consistently resolved as sister to Dicranidae, and this lineage has a high posterior probability under the Bayesian criterion. Within the Dicranidae, a core clade is resolved that comprises most of the species sampled, and all analyses identify a proto-haplolepideous grade of taxa previously placed in various haplolepideous families. The data provide considerable resolution of relationships within the core Dicranidae, yielding a number of well-supported clades. These correspond only roughly to taxa that are currently recognised, and most families and orders of Dicranidae apparently are non-monophyletic under their current circumscriptions.