Two new species of Haptoglossa from north-east England

Two new species of Haptoglossa , one zoosporic, H. northumbrica , and one aplanosporic, H. polymorphs, , were isolated from samples of manure and horse dung in north-east England. The zoosporic H. northumbrica is morphologically similar to H. dickii but differs in having slightly smaller infection gun cells with a unique internal arrangement of cones in the apical missile chamber. The thallus of the aplanosporic H. polymorpha is similar to H. heteromorpha but produces three different types of aplanospore. The smaller cysts either develop into broad, arcuate gun cells or form curved adhesive cells that have a rounded base. These curved adhesive cells have very different internal ultrastructural organization. The large cysts develop into infection cells that are morphologically similar to the curved adhesive cells, but their internal structure has not yet been observed.     

Schizogony and Gametogony of Leucocytozoon simondi and Associated Reactions in the Avian Host*

SYNOPSIS. Stages of development of Leucocytozoon simondi in White Pekin ducklings and their reactions to the parasite were studied on successive days after infecting them artificially with sporozoites from Simulium rugglesi. The minimum prepatent period was 5 days. The first asexual cycle occurred exclusively in the parenchymal cells of the liver. Progeny of these hepatic schizonts followed one of 3 courses: (a) invaded parenchymal liver cells to give rise to another hepatic cycle, (b) penetrated blood cells to form round gametocytes, and (c) were phagocytized by macrophages and grew into megaloschizonts thruout the body. The appearance of elongating gametocytes coincided with the period of maturation and release of merozoites from the megaloschizonts. Experimental evidence supports the hypothesis that the round gametocytes arise from the hepatic schizonts and the elongate forms from the megaloschizonts. Mature megaloschizonts released millions of merozoites, but a high 2nd peak in parasitemia did not develop because of retention of developing gametocytes in the deep circulation, particularly the liver and spleen, and a pronounced host reaction.     

Fine Structure of Oocyst Transformation and the Sporozoites of Leucocytozoon dubreuili*

SYNOPSIS. The sporogonic stages of Leucocytozoon dubreuili in the midgut and salivary glands of the simuliid vectors was studied by electron microscopy. Young uninucleate oocysts have a pellicle that initially resembles that of the ookinetc. Numerous electron-dense bodies and microtubules in the peripheral cytoplasm may be involved in the formation of the cyst wall. The dense bodies appear to give rise to the amorphous material of the wall. The tubules which run circumferentially beneath the oocyst's boundary probably serve as a skeletal support for the cell surface during deposition of the wall material. A subcapsular “space” which provides area for expansion of the developing sporozoites is formed in early multinucleate oocysts. The subcapsular “space” appears to be formed through a condensation of the peripheral cytoplasm, resulting in an osmotic gradient across the oocyst's limiting membrane. Consequently water diffuses out, creating a fluid-filled space. Sporozoite formation begins with localized thickenings on the oocyst's limiting membrane. Subsequent extension of the thickened regions into the subcapsular “space” marks the onset of sporozoite budding. The process is highly synchronized, and culminates with the production of up to 150 sporozoites about the sporoblastoid body. The structure of sporozoites from mature oocysts and of the salivary glands of the vector is basically similar, although salivary gland sporozoites are more elongate and have numerous electron-dense micronemes. The paired rhoptries in the latter sporozoites are more elongate and uniformly electron-dense than in oocyst sporozoites.     

Humans and other animals and the plants they ingest

Primula allionii is endemic to a tiny area of the Maritime Alps and has one of the narrowest distribution ranges in this hotspot of biodiversity. Phylogeographical patterns in P. allionii were studied using plastid DNA markers and dominantly inherited markers (AFLP and ISSR) to verify any admixture between P. allionii and the sympatric P. marginata and to detect the phylogeographical history of the species. Morphometric measurements of flowers and admixture analysis support the hypothesis that hybridization occurs in nature. Species distribution models using two climate models (CCSM and MIROC) suggested a reduction in habitat suitability during cold periods. Phylogeographical analysis suggested an old allopatric divergence during the mid‐Pleistocene transition (about 0.8 Mya) without recolonization/contraction cycles. The Alps watershed does not act as a strong barrier between the two main areas of the distribution range, and moderate gene flow by pollen seems to create the admixture recorded among the stands. According to our results, the persistence of P. allionii throughout the Ice Age appears to be linked to the capacity of the Maritime Alps to provide a wide diversity of microhabitats consistent with the recent biogeographical pattern proposed for the Mediterranean Basin. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 637–653.     

Reassessment of cf. Halticosaurus orbitoangulatus from the Upper Triassic (Norian) of Germany – a pseudosuchian,not a dinosaur

The holotype of cf. Halticosaurus orbitoangulatus Huene, 1932, comprises an incomplete and macerated but associated skull of an archosaurian reptile from the middle (second) Stubensandstein (middle Löwenstein Formation; Upper Triassic: Norian) of Baden‐Württemberg, Germany. It was originally interpreted as a theropod dinosaur but more recently it has been suggested that this taxon has crocodylomorph affinities. Detailed preparation of the holotype of cf. H. orbitoangulatus has revealed much new anatomical information and permitted reassessment of its affinities. The maxilla lacks both a distinct antorbital fossa and a medial bony lamina bordering the antorbital fenestra. The lateral surface of the dentary bears a pronounced horizontal ridge. The squamosal differs from that of basal crocodylomorphs in being L‐shaped rather than arcuate in dorsal view, lacking a dorsolateral overhang, and lacking an interlocking contact with the paroccipital process as, for example, in the basal crocodylomorph Saltoposuchus connectens from the same horizon and locality. Phylogenetic analysis placed cf. H. orbitoangulatus amongst loricatan pseudosuchians (but not amongst Crocodylomorpha) rather than amongst theropod dinosaurs. The holotype of cf. H. orbitoangulatus represents a previously unrecognized taxon of loricatan pseudosuchian, which is here named Apatosuchus orbitoangulatus and set apart from other known Norian‐age non‐crocodylomorph loricatans by its apparently much smaller size. © 2013 The Linnean Society of London     

Determinants of some leaf characteristics of Australian mangroves

Leaf characteristics reflecting the size, lifespan (longevity), moisture content (degree of succulence) and complexity of structure of 20 mangrove species were studied over several years at 13 locations along the tropical and subtropical Australian coast. These characteristics were found to fall generally within the ranges of those for woody species from other ecosystems. With the exception of one species, it was found that leaf longevity was related inversely to leaf moisture content, increasing from nearly 6 months in more succulent species to over 2 years in less succulent species. This suggested that more succulent leaves are less complex in their structure because they have less well‐developed ability to compartmentalize salt. There was a tendency also for leaf longevity to increase in species with larger leaves. These findings were consistent with the general view for land plants that leaf longevity is greater in species that have developed tolerance to environmental stress, salt particularly in the case of mangroves. Leaf tissue in such species is more robust or complex and requires greater metabolic resources in its construction; the plant is then advantaged by retaining the tissue for longer periods. Classification of the species considered here, based on their leaf longevity, moisture content and complexity, identified phylogenetically related species groupings that reflected these leaf longevity effects.     

Litter‐trapping plants: filter‐feeders of the plant kingdom

Litter‐trapping plants have specialized growth habits and morphologies that enable them to capture falling leaf litter and other debris, which the plants use for nutrition after the litter has decayed. Litter is trapped via rosettes of leaves, specially modified leaves and/or upward‐growing roots (so‐called ‘root baskets’). Litter‐trappers, both epiphytic and terrestrial, are found throughout the tropics, with only a few extra‐tropical species, and they have evolved in many plant families. The trapped litter mass is a source of nutrients for litter‐trapping plants, as well as food and housing for commensal organisms. Despite their unique mode of life, litter‐trapping plants are not well documented, and many questions remain about their distribution, physiology and evolution.–© 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 554–586.