Radiation, multiple dispersal and parallelism in the skinks, Chalcides and Sphenops (Squamata: Scincidae), with comments on Scincus and Scincopus and the age of the Sahara Desert

Phylogenetic analysis using up to 1325 base pairs of mitochondrial DNA from 179 specimens and 30 species of Chalcides, Sphenops, Eumeces, Scincopus and Scincus indicates that Sphenops arose twice independently within Chalcides. It is consequently synonymized with that genus. Chalcides in this broader sense originated in Morocco, diversifying into four main clades about 10 Ma, after which some of its lineages dispersed widely to cover an area 40 times as large. Two separate lineages invaded the Canary Islands and at least five main lineages colonized southern Europe. At least five more spread across northern Africa, one extending into southwest Asia. Elongate bodies with reduced limbs have evolved at least four times in Chalcides, mesic 'grass-swimmers' being produced in one case and extensive adaptation to life in loose desert sand in two others. In clade, Chalcides striatus colonized SW Europe from NW Africa 2.6 Ma and C. chalcides mainland Italy 1.4 Ma, both invasions being across water, while C. c. vittatus reached Sardinia more recently, perhaps anthropogenically, and C. guentheri spread 1200km further east to Israel. C. minutus is a composite, with individuals from the type locality forming a long independent lineage and the remaining ones investigated being most closely related to C. mertensi. In the Northern clade, C. boulengeri and C. sepsoides spread east through sandy habitats north of the Sahara about 5 Ma, the latter reaching Egypt. C. bedriagai invaded Spain around the same time, perhaps during the Messinian period when the Mediterranean was dry, and shows considerable diversification. Although it is currently recognized as one species, the C. ocellatus clade exhibits as much phylogenetic depth as the other main clades of Chalcides, having at least six main lineages. These have independently invaded Malta and Sardinia from Tunisia and also southwest Arabia C. o. humilis appears to have spread over 4000 km through the Sahel, south of the Sahara quite recently, perhaps in the Pleistocene. In the Western clade of Chalcides, C. delislei appears to have dispersed in a similar way. There were also two invasions of the Canary Islands: one around 5 Ma by C. simonyi, and the other about 7 Ma by the ancestor of C. viridanus+C. sexlineatus. C. montanus was believed to be related to C. lanzai of the Northern clade, but in the mtDNA tree it is placed within C. polylepis of the Western clade, although this may possibly be an artifact of introgression. The Eumeces schneideri group, Scincopus and Scincus form a clade separate from Chalcides. Within this clade, the geographically disjunct E. schneideri group is paraphyletic. One of its members, E. algeriensis is the sister taxon to Scincopus, and Scincus may also be related to these taxa. The phylogeny suggests Scincopus entered desert conditions in Africa, up to 9.6 Ma and the same may have been true of Scincus up to 11.7 Ma. Scincus appears to have diversified and spread into Arabia around 6 Ma. Dates of origin and divergence of these skinks, desert Chalcides and other squamates agree with recent geological evidence that the Sahara is at least 5-7 My old. The subspecies Chalcides viridanus coeruleopunctatus is upgraded to the species level as C. coeruleopunctatus stat nov., on the basis of its large genetic divergence from C. v. viridanus.     

Enameloid/enamel transition through successive tooth replacements in <Emphasis Type="Italic">Pleurodeles waltl</Emphasis> (Lissamphibia,Caudata)

Study of the evolutionary enameloid/enamel transition suffers from discontinuous data in the fossil record, although a developmental enameloid/enamel transition exists in living caudates, salamanders and newts. The timing and manner in which the enameloid/enamel transition is achieved during caudate ontogeny is of great interest, because the caudate situation could reflect events that have occurred during evolution. Using light and transmission electron microscopy, we have monitored the formation of the upper tooth region in six successive teeth of a tooth family (position I) in Pleurodeles waltl from late embryos to young adult. Enameloid has only been identified in embryonic tooth I₁ and in larval teeth I₂ and I₃. A thin layer of enamel is deposited later by ameloblasts on the enameloid surface of these teeth. From post-metamorphic juvenile onwards, teeth are covered with enamel only. The collagen-rich enameloid matrix is deposited by odontoblasts, which subsequently form dentin. Enameloid, like enamel, mineralizes and then matures but ameloblast participation in enameloid matrix deposition has not been established. From tooth I₁ to tooth I₃, the enameloid matrix becomes ever more dense and increasingly comes to resemble the dentin matrix, although it is still subjected to maturation. Our data suggest the absence of an enameloid/enamel transition and, instead, the occurrence of an enameloid/dentin transition, which seems to result from a progressive slowing down of odontoblast activity. As a consequence, the ameloblasts in post-metamorphic teeth appear to synthesize the enamel matrix earlier than in larval teeth.     

Comparative floral anatomy of Strobilanthinae (Acanthaceae), with particular reference to internal partitioning of the flower

This paper provides the first comparative survey of structural variation in inflorescence architecture and flower structure of Hemigraphis and other members of the subtribe Strobilanthinae (Acanthaceae). Several discrete structural characters are identified which may provide support for phylogenetic relationships within the group. These include (1) the presence or absence of an accessory bud, (2) the presence or absence of a hollow style, (3) the presence or absence of an abscission layer, (4) the number of stamens comprising the androecium, and (5) the pattern of filament detachment. The structure of the filament curtain, a complex structure that partitions the flower, is also investigated. A more precise term for this structure stapetal curtain is suggested since it is a result of close synorganisation between the filaments and corolla tube. This structure appears to have a wide distribution throughout Acanthaceae and is not confined to Ruellieae s.l., as previously described. The earlier characterisation of four discrete types of filament curtain is unsatisfactory, since many of the features used to distinguish them are continuous and not unique features of particular species.We acknowledge Richard Bateman, Mark Carine, Peter Endress, Colin Hughes, Toby Pennington and an anonymous reviewer for comments on this paper. ECM gratefully acknowledges Chrissie Prychid, Peter Gasson, and the late Tim Lawrence of the Micromorphology section, Royal Botanic Gardens, Kew for their assistance and encouragement and Jesus Cordero-Salvado for help with the figures. This work was supported by the Druce Fund from the University of Oxford.     

Scanning electron-microscopical study of epididymal secretions in the lizard Lacerta vivipara (Reptilia,Squamata) and of their relationships with spermatozoa

Cell and Tissue Research - During the breeding season (April, May) the epididymis of the lizard Lacerta vivipara produces voluminous secretory granules which are abundantly discharged into the...     

Structure and development of the ovule and seed in Aristolochiaceae, with particular reference to Saruma

All members of Aristolochiaceae have anatropous, bitegmic, crassinucellate ovules, which are endostomic except in Saruma and Asarum arifolium where ovules are amphistomic. The outer integument is two cell-layered and the inner integument is three cell-layered. The chalazal megaspore is the functional one. All these conditions appear to be plesiomorphic for the order Piperales, which consists of five families, Aristolochiaceae, Hydnoraceae, Lactoridaceae, Piperaceae and Saururaceae. The embryo sac in Aristolochiaceae is eight-nucleate and corresponds to the Polygonum type; a hypostase is frequently present in this family. The seed coat of Aristolochia s.l., Asarum, Saruma and some Thottea species consists primarily of a two cell-layered testa, and a three cell-layered tegmen. In some species the cells of the outer epidermis become radially elongated, forming reticulate wall thickenings. Cells of the inner layer of the testa have crystals and thickened inner walls. The three layers of the tegmen are tangentially elongated, and become cross fibres at maturity, as fibres of the outer and inner layers are parallel to the seed axis, whereas those of the middle layer are perpendicular to it. This type of seed coat anatomy is synapomorphic for Aristolochiaceae. In addition, the gross morphology of the seed and elaiosome histology are remarkably similar in Asarum and Saruma, thus supporting a sister-group relationship between them. Embryological and seed characters do not supply any synapomorphy that support a close relationship between Aristolochiaceae, Hydnoraceae and Lactoridaceae. Instead, some seed features such as the absence of seed appendages and the collapsed cells of endotesta may indicate a close relationship of Lactoris with Piperaceae plus Saururaceae, although this is the subject of further analysis.     

True enamel matrix of the newt,Triturus pyrrhogaster,contains no sulfated glycoconjugates

Summary The ultrastructural distibution and histochemical properties of sulfated glycoconjugates were investigated in the developing enamel of the adult newt, Triturus pyrrhogaster, by use of the high-iron diamine thiocarbohydrazide silver proteinate (HID-TCH-SP) staining and enzymatic digestion methods. Development and ultrastructure of the enamel were also studied. After deposition of the mantle dentin matrix to a certain thickness, the first enamel matrix, globular in shape, appeared in juxtaposition to the dental basement membrane and tended to be intermixed with the previously deposited dentin matrix. Subsequently, enamel matrix was deposited outside (ameloblastic side) of the dental basal lamina and formed a true enamel layer. Thus, developing enamel of the newt consists of two layers: (1) an inner layer made up of a dentin-enamel mixed matrix and (2) an outer layer composed of only true enamel matrix. HID-TCH-SP precipitates resulting from the abovementioned studies were found in the mixed matrix and were identified as chondroitin sulfates; in contrast, the true enamel matrix contained no sulfated glycoconjugates.     

The larval development of an Australian limnadiid clam shrimp (Crustacea, Branchiopoda, Spinicaudata), and a comparison with other Limnadiidae

The adult morphology of the Australian Limnadopsis shows some remarkable differences to that of other Limnadiidae. These differences are not reflected in its larval development. In Limnadopsis parvispinus, larval development comprises six stages. In stages I and II only the three naupliar appendages are present: the antennule as a small bud, the biramous antenna as the main swimming organ, and the mandible. The antennal protopod bears two endites, the proximal naupliar process and a more distal endite. In stage III a bifid naupliar process (in earlier stages not bifid) and the first signs of the carapace and trunk limb anlagen (undifferentiated rudiments) appear. In stage IV the carapace anlagen become more pronounced. The number of trunk limb anlagens increases to five, and differentiation has commenced. In stage V the first five pairs of trunk limbs are differentiated to varying degrees. The anterior-most four pairs of trunk limbs are subdivided into five endites, a small endopod, an exopod and an epipod. The bivalved carapace covers the anterior-most limbs. In larval stage VI the carapace is larger and the trunk limbs are further differentiated. A general pattern in the sequence of larval stages is the increasing number of sensilla on the antennules. From the last larval to the first postlarval stage, a significant change in morphology takes place. The trunk limbs are now used for swimming. Typical larval organs are much smaller than in the last larval stage. A comparison with other representatives of the Limnadiidae shows a high degree of correspondence, with most differences explained by the heterochronous appearance of characters during development. Five to seven stages are described for all studied Limnadiidae, including one particular stage in which four fully developed setae, a bifid naupliar process and the first signs of carapace anlagen are present. These characters are found in stage III in L. parvispinus, Limnadia stanleyana, Eulimnadia texana, and Imnadia yeyetta but in stage IV in E. braueriana and L. lenticularis. Based on a comparison of the larval stages of six limnadiid and one cyzicid species, we conclude that at least six naupliar stages belong to the limnadiid ground pattern.     

Molecular evidence for a species complex in the patagonian lizard Liolaemus bibronii and phylogeography of the closely related Liolaemus gracilis (Squamata: Liolaemini)

The lizard genus Liolaemus is endemic to temperate South America and includes 190 species. Liolaemus bibronii has a large geographic distribution and inhabits a great diversity of habitats, including the Monte, Steppe, and high Andean grassland environments. Liolaemus gracilis has a similar body size and shape to L. bibronii; the two are parapatrically distributed, and L. gracilis is also widely distributed. Here we use the mtDNA cytb sequence data of these two species to investigate lizard phylogeographic patterns in southern South America. L. bibronii is paraphyletic with respect to L. gracilis, Liolaemus ramirezae, Liolaemus robertmertensi and Liolaemus saxatilis; it is composed of many genetically different allopatric haploclades, some of which are reciprocally monophyletic. We also found evidence for introgression between L. bibronii and L. gracilis in the same area that introgression was hypothesized in the Liolaemus darwinii complex. We discuss the distribution of the major haploclades with inferences of their population histories, the concordance of these clades' distributions and histories with other lizard complexes studied with the same markers and methods, and taxonomic implications of these results.     

Mallomonas alphaphora (Chrysophyceae), a new species from Western Australia

A new species ofMallomonas, M. alphaphora (Chrysophyceae), was found in freshwater ponds in the Perth region, Western Australia. It is distinguished from other species ofMallomonas by its very distinctive scale and bristle morphology and is placed in a new section,Alphaphorae, of the genusMallomonas. Dedicated to Prof. DrL. Geitler on the occasion of the 90th anniversary of his birthday.     

Molecular systematics of the African snake family Lamprophiidae Fitzinger, 1843 (Serpentes: Elapoidea), with particular focus on the genera Lamprophis Fitzinger 1843 and Mehelya Csiki 1903

The snake family Lamprophiidae Fitzinger (Serpentes: Elapoidea) is a putatively Late Eocene radiation of nocturnal snakes endemic to the African continent. It incorporates many of the most characteristic and prolific of Africa's non-venomous snake species, including the widespread type genus Lamprophis Fitzinger, 1843 (house snakes). We used approximately 2500 bases of mitochondrial and nuclear DNA sequence data from 28 (41%) of the approximately 68 recognised lamprophiid species in nine of the eleven genera to investigate phylogenetic structure in the family and to inform taxonomy at the generic level. Cytochrome b, ND4 and tRNA gene sequences (mitochondrial) and c-mos sequences (nuclear) were analysed using Maximum Likelihood, Bayesian Inference and Maximum Parsimony methods. The genus Mehelya Csiki, 1903 was paraphyletic with respect to Gonionotophis Boulenger, 1893. To address this, the concept of Gonionotophis is expanded to include all current Mehelya species. The genus Lamprophis emerged polyphyletic: the enigmatic Lamprophis swazicus was sister to Hormonotus modestus from West Africa, and not closely related to its nominal congeners. It is moved to a new monotypic genus (Inyoka gen. nov.). The remaining Lamprophis species occur in three early-diverging lineages. (1) Lamprophis virgatus and the widely distributed Lamprophis fuliginosus species complex (which also includes Lamprophis lineatus and Lamprophis olivaceus) formed a clade for which the generic name Boaedon Duméril, Bibron & Duméril, 1854 is resurrected. (2) The water snakes (Lycodonomorphus) were nested within Lamprophis (sensu lato), sister to Lamprophis inornatus. We transfer this species to the genus Lycodonomorphus Fitzinger, 1843. (3) We restrict Lamprophis (sensu strictissimo) to a small clade of four species endemic to southern Africa: the type species of Lamprophis Fitzinger, 1843 (Lamprophis aurora) plus Lamprophis fiskii, Lamprophis fuscus and Lamprophis guttatus.     

Inflorescence and floral development in Streptocarpus and Saintpaulia (Gesneriaceae) with particular reference to the impact of bracteole suppression

Floral development and inflorescence structure within Streptocarpus and Saintpaulia were investigated using Scanning Electron Microscopy (SEM). We discuss the structure and development of the pair-flowered cyme and the floral ontogeny found in the Gesneriaceae in a phylogenetic context with particular reference to an East African clade of Streptocarpus and Saintpaulia. Current phylogenetic hypotheses divide the caulescent East African Streptocarpus species into two distinct clades, in relation to which the position of Saintpaulia is not yet clear. Variation in the branching of the inflorescence showed phylogenetic significance and included dichasial, monochasial and unbranched patterns. In four of the East African Streptocarpus species sampled a single lateral bracteole was present on the first to third axes, after which the inflorescence was ebracteolate. Our results indicate that there may be some link between bracteole suppression and an alteration in the order of sepal initiation. The loss or suppression of lateral bracteoles also appears to result in the precocious development of the lateral cyme meristem.     

Distribution and development of the serotonin-and RFamide-like immunoreactive neurons in the arrowworm,Paraspadella gotoi (Chaetognatha)

Summary The distribution and development of serotonin-and RFamide-like immunoreactivities in the nervous system of Chaetognatha, Paraspadella gotoi, were examined in whole-mount preparations. In adults, a single serotonin-like immunoreactive (5HTLI) neuron and numerous RFamide-like immunoreactive (RFaLI) neurons were found in the central nervous system. Based on the structure of the fins, hooks, and eyes, seven postembryonic developmental stages were recognized. The most obvious features of the stages are: stage 1, newly hatched young; stage 2, elongation of a continuous lateral tail fin; stage 3, separation of the lateral and tail fins; stage 4, appearance of hooks; stage 5, pigmentation of eyes, stage 6, attachment by tail adhesive fins; stage 7, prey capture. Stage 1 did not show any immunoreactivity. The 5HTLI neuron first appeared at stage 4 and its axonal pathway became similar to the adult at stage 6. On the other hand, the RFaLI neurons appeared at stage 3 in the ventral ganglion. Some of their somata disappeared at stage 5 and the neuronal architecture resembled the adult at stage 7 although the RFaLI neurons in the cerebral ganglion were complete at the juvenile stage.We are sad to announce that Dr. M. Yoshida died on 29 October 1988     

Morphology and development of rhabdovirus-like particles inCuscuta odorata (Convolvulaceae) simultaneous infected with virus and mycoplasma-like organisms

Summary Electron microscopic examination ofCuscuta odorata, used for transmission trials, revealed mycoplasma-like organisms (MLO) as well as rhabdovirus-like particles, unknown toCuscuta. The virus infection is confined to certain phloem-parenchyma cells and a 1–2 cell thick layer of parenchyma cells with thickened walls surrounding the central cylinder. Virus particles, mostly bacilliform, could be detected mainly in the nucleus but also in the cytoplasm. They reach a length of 350–400 nm and a diameter of approximately 75 nm. Virus assembly takes place exclusively in the nucleus. Virus maturation occurs in membrane bound areas within the nucleus, which have no connection with the perinuclear space. Formation of nucleocapsids is always associated with a nuclear viroplasm. Envelopment of virus particles occurs in these membrane bound areas. Budding into the perinuclear space does not occur. Virus infection leads to degeneration and finally to death of the protoplast.Abbreviations cy cytoplasm - m membrane stacks - mt mitochondria - my mycoplasma-like organisms - nc nucleocapsid - ncp nucleocapsid particles - nf nuclear filaments - np nucleoplasm - nu nucleus - nvp nuclear viroplasm - oc obliterated cells - p plastid - pc passage cells - ph phloem - ps perinuclear space - spc strand of parenchymatous cells - v virus particle - x xylem     

Neuronal background of activation of estivated snails,with special attention to the monoaminergic system: a biochemical,physiological, and neuroanatomical study

Osmotic stimulation activates both estivated and inactivated specimens of Helix pomatia and increases their central arousal. High-pressure liquid chromatography has shown that, during activation, the level of both serotonin and dopamine decreases in the central nervous system (CNS) but increases in the foot and heart, organs that are involved in the eversion of the body. In isolated CNS from activated animals, the firing frequency of the heart-modulator serotonergic (RPas) neurons is significantly higher than that in the CNS of estivated or inactivated animals. These neurons innervate both the heart and the anterior aorta. In semi-intact preparations, distilled water (an osmotic stimulus) applied to the mantle collar increases their firing frequency, whereas tactile stimulation evokes their inhibition. Extracellularly applied monoamines mimic the effect of peripheral stimuli: serotonin (0.1–10 μM) increases the activity of the RPas neurons, whereas dopamine (0.1–10 μM) inhibits their activity. Tyrosine-hydroxylase immunocytochemistry and retrograde neurobiotin tracing have revealed similar bipolar receptor cells in the mantle collar and tail, organs that are exposed to environmental stimuli in estivated animals. Serotonin immunocytochemistry carried out on the same tissues does not visualize receptor cells but labels a dense network of fibers that appear to innervate neurobiotin-labeled receptor cells. The combination of neurobiotin-labeling of RPas neurons and immunolabeling suggests that RPas neurons receive direct dopaminergic inputs from receptor cells and serotonergic inputs from central serotonergic neurons, indicating that central serotonergic neurons are interconnected. Thus, the RPas neurons may belong to neuronal elements of the arousal system. This work was supported by Hungarian OTKA grants T037389, T046580, T037505, and K63451.     

A microscopic investigation of enamel in wombat (Vombatus ursinus)

Summary A study of the enamel of continuously growing Vombatus ursinus molars was carried out using the techniques of light microscopy, hardness testing, scanning electron microscopy and transmission electron microscopy. From the erupted end to within 8 mm of the growing end, mature enamel was observed and it was found that between comparable areas there were no significant ultrastructural differences in enamel; however, small (12nm diameter), loosely packed needle-like crystals characteristic of developing enamel were observed near the growing end. Mature enamel was found to consist of three optically-translucent regions interleaved with two opaque regions. Opaque enamel was softer than translucent enamel. The opacity and relative softness characteristic of two of the enamel regions was not related to prism pattern or orientation; it was, however, related to the presence of voids (28 nm diameter) in these regions.     

Antinematodal activity and the mechanism of the antimicrobial peptide, HP (2-20), against Caenorhabditis elegans

The peptide HP (2-20), derived from the N-terminal sequence of Helicobacter pylori ribosomal protein L1 (RPL1), has a nematicidal activity against eggs and worms of Caenorhabditis elegans. Eggs treated with HP (2-20) (69%) has a higher fluorescence intensity with propidium iodide staining, which was similar to that of melittin (82%) but higher than untreated cells (5.7%). Confocal microscopy showed that the peptides were located in the shell of the eggs and the inner and outer surfaces of the worms. HP (2-20) therefore may exert its antinematodal activity by disrupting the structure of the egg's shell and the cell membrane via pore formation or by direct interaction with the lipid bilayers in a detergent-like manner.     

Paraheminodus kochiensis Kamohara, 1957 (Teleostei: Peristediidae), a junior synonym of Paraheminodus murrayi (GÜnther, 1880), with a comparison of Paraheminodus murrayi and Paraheminodus laticephalus (Kamohara, 1952)

Paraheminodus kochiensis Kamohara, 1957 (family Peristediidae), has been regarded by most workers as a junior synonym of P. murrayi (GÜnther, 1880), but sufficient argument for combining the two species has not been made. A detailed comparison of the type and non-type material of P. kochiensis and P. murrayi revealed no significant differences between the two; thus, their synonymy is hereby confirmed. Paraheminodus murrayi and P. laticephalus (Kamohara, 1952) are clearly distinguished by the morphology of the upper jaw teeth, length of the upper jaw, and by the number of barbels.     

Quantitative comparison of foliage development amongDryopteris monticola,D. tokyoensis and a putative hybrid,D. kominatoensis in Northern Japan

Developmental leaf architecture was quantitatively described in terms of measurements of various parameters on leaf blade from different size of sporophytes inDryopteris monticola, D. tokyoensis and a putative hybrid,D. kominatoensis in the natural site of Hokkaido, to compare the ontogenetic differentiation in foliage structure among allied ferns. The morphological stage of leaf and sporophyte was tentatively quantified by the number of midrib branches of the leaf (NV, number of veins), which exhibited a significant correlation to the leaf-shape complexity from a circle (DI=marginal length/2×(3.14×square)^1/2) of leaf blade. D. kominatoensis showed intermediate values between others in following characters; DI increase, maximum NV (also blade length), maximum number of costa branches of pinnae (NVMP), number of costa branches of the lowest pinna (NVLP), difference between NVMP and NVLP (NVMP-NVLP), during heteroblastic leaf development. A larger number of leaves per sporophyte was found inD. kominatoensis than in others. The fertility rate (%) and initiation of fertility (IF) in the relative developmental stage (RDS) ofD. kominatoensis shifted to that ofD. tokyoensis, while the order of pinnae with NVMP shifted to that ofD. monticola. Even in the intermediate characters inD. kominatoensis, slight shifts in characters to those of putative parents were found during heteroblastic leaf development. Contribution No. 3145 from the Institute of Low Temperature Science, Hokkaido University.