Two new taxa in the Section Papillosae of the genus Mallomonas (Synurophyceae) from the Ocala National Forest, Florida, USA

Two new species of Mallomonas, M. binocularis and M. delanciana , are described from small, acidic, poorly buffered waterbodies in the Ocala National Forest, Florida, U.S.A. Both taxa are in the Section Papillosae, consist of relatively small cells covered with domed scales each bearing a single bristle, and have small tripartite scales with a small symmetrically placed dome. Scales of Mallomonas binocularis have shields that are covered with evenly-spaced papillae, two distinctive pores at the base of the V-rib and unornamented flanges. Mallomonas binocularis is most similar to Mallomonas paxillata, M. papillosa, M. rasilis and M. calceolus , but can be distinguished from the latter taxa on the basis of scale structure and bristle morphology. Scales of Mallomonas delanciana have shields with widely spaced papillae, a series of parallel ribs on the anterior flanges that usually continue around the dome, unornamented posterior flanges and lack rimmed pores in the posterior region of the shield. The density of the papillae on the shield, features of the dome and anterior flange, and the structure of bristles, clearly serve to separate M. delanciana from closely related species including M. papillosa, M. calceolus and Mallomonas conspersa.     

Two new species of Mallomonas (Synurophyceae) from the Ocala National Forest, Florida, U.S.A.

Two new species of Mallomonas, M. ocalensis and M. caerula , are described from a clearwater, acidic and oligotrophic waterbody in the Ocala National Forest, Florida, U.S.A. Mallomonas ocalensis , in the Series Doignonianae of the Section Torquatae, consists of relatively small cells with scales that have a series of parallel shield ribs with alternating thicknesses, collar scales with very short bristles and posterior scales with small protruding spines. Mallomonas ocalensis is most similar to Mallomonas dickii , but is distinguished from the latter species based on the highly variable thicknesses of the shield ribs and significantly larger scales. Mallomonas caerula , in the Series Mallomonas of the Section Mallomonas, consists of relatively large cells that bear large domed and dorneless scales, and long, robust and ribbed bristles. Bristles with and without helmets can be found. The shield, especially the distal portion, and the posterior flange of scales consists of series of more or less parallel ribs. Mallomonas caerula appears to be most closely related to Mallomonas acaroides var. acaroides and Mallomonas acaroides var. muskokana , but can be distinguished from the latter taxa on the basis of scale type, scale structure and bristle morphology. Both new species were found in the plankton and surface sediments of Blue Sink Pond.     

SEPERATION OF MALLOMONAS DUERRSCHMIDTIAE SP. NOV. FROM M. CRASSISQUAMA AND M. PSEUDOCORONATA: IMPLICATIONS FOR PALEOLIMNOLOGICAL RESEARCH1

A new species, Mallomonas duerrschmidtiae, with characteristics common to both Mallomonas crassisquama (Asmund) Fott and Mallomonas pseudocoronata Prescott, is described from acidic lakes low in specific conductance and total phosphorus concentration. Characteristics of scales, bristles and spines serve to separate the three taxa. The length and area of scales of M. duerrschmidtiae are significantly larger than those of M. crassisquama but smaller than those of M. pseudocoronata. Although the anterior submarginal ribs of scales of M. duerrschmidtiae may become extended to form short wings, the scales lack the large forward projecting anterior wings characteristic of scales of M. pseudocoronata. Features of the dome and junction between the arms of the V-rib and anterior submarginal ribs also serve to distinguish between the three species. Cells of M. duerrschmidtiae also possess long, smooth and thick spines on their posterior scales and lack helmet bristles. M. duerrschmidtiae has different maxima along pH, temperature, specific conductance, total phosphorus and seasonal gradients than either M. crassisquama or M. pseudocoronata. Discriminant analysis, based on nine morphological characters, was used to successfully classify body scales of the three species. The importance of M. duerrschmidtiae as a bioindicator in future lake monitoring and paleolimnological inference studies is discussed.     

Mallomonas retrorsa, a new species of silica-scaled Chrysophyceae with backwards orientated scales

A new species, Mallomonas retrorsa , with a unique siliceous armour, is described from four slightly humic and acidic localities in Connecticut, U.S.A., each low in specific conductance. Cells of the new species have three types of siliceous scales each of which is asymmetric, domeless and arranged with their longitudinal axis parallel to the longitudinal axis of the cell. The scales are positioned such that the posterior rim of each scale faces the apical end of the cell. In addition, the new taxon has an apical whorl of very small, forward projecting paddle-shaped bristles that emerge from the rimmed ends of the apical scales, and an elongated caudal region.     

Mallomonas jejuensis sp. nov. (Synurophyceae) from Jeju Island,South Korea

A new species of Mallomonas (Synurophyceae), Mallomonas jejuensis sp. nov., has been found in Jeju Island, South Korea. This species is placed in the series Mangoferae (section Torquatae) because it has a collar of elongated domed scales, domeless body scales, rear scales with spines and all scales ornamented with papillae. The morphological characteristics of the scales and bristle of the new species are described by EM and compared with those reported for the other species of the series Mangoferae.     

Mallomonas connensis sp. nov., a new species of Synurophyceae from a small New England lake, U.S.A.

A new species of Mallomonas, M. connensis sp. nov., is described from a eutrophic locality in Connecticut, U.S.A. with a relatively high pH and specific conductance. Cells are covered with bristles and have scales that are orientated with their longitudinal axes perpendicular to the longitudinal axis of the cell. Each scale of the apical ring is highly asymmetrical with a forward projecting triangular shaped extension; collectively the extensions form an opening through which the flagellum emerges. Body scales possess a prominent Ushaped ridge that transverses the scale near the center and extends forward. A series of more or less concentric ribs cover the U-shaped ridge and dome, and circumscribe a more light and electron transparent region. The combination of characters of the bristles is unique among taxa of Mallomonas .     

Stomatocysts of Mallomonas hamata and M. heterospina (Mallomonadaceae, Synurophyceae) from South Swedish lakes

The stomato cysts of Mallomonas hamata and M. heterospina are described from lakes in South Sweden. These Mallomonas species develop cysts of similar appearance, size and form. Cyst formation for Mallomonas hamata was recorded at temperature 10–11°C and pH 5.9 and for M. heterospina at temperatures 4.2–11°C and pH 7.4. The cysts of M. hamata and M. heterospina are ovoid and easy to recognize, even with light microscopy, but difficult to distinguish from another. Thus their value as paleoindicators is limited, even if the two species have preference for waters of different nutrient and pH status.     

Exploring Cryptic Diversity and Distribution Patterns in the Mallomonas kalinae/rasilis Species Complex with a Description of a New Taxon—Mallomonas furtiva sp. nov.

A complex of closely related Mallomonas taxa belonging to the section Papillosae, M. kalinae ?ezá?ová and M. rasilis Dürrschmidt, has been studied in detail by molecular and morphometric methods. Our investigations uncovered the existence of a new species found in water bodies in Vietnam, which we describe here as Mallomonas furtiva sp. nov. This taxon is morphologically very similar to M. kalinae , from which it differs by minute, but statistically significant morphological differences on the structure of silica scales. Indeed, the principal component analysis of morphological traits measured on silica scales significantly separates all three species in the complex. Mallomonas kalinae and M . furtiva differ by number of papillae on the shield and the dome, as well as by the scale sizes. Likewise, Mallomonas rasilis and M. furtiva are primarily differentiated by the absence of submarginal anterior ribs on silica scales of the former species. Phylogenetic analyses showed that Mallomonas furtiva is closely related to M . kalinae , with which it formed a highly supported lineage. Distribution patterns of all three studied taxa are further discussed.     

Mallomonas weei (Synurophyceae), a new species from North Carolina, U.S.A.

A new species of Mallomonas, M.weei, is described from North Carolina, U.S.A. Fine structure of scales and bristles has been studied using scanning and transmission electron microscopy. The new species is placed in the section Mallomonas, series Intermediae.     

Mallomonas nieringii sp. nov., a new species of Synurophyceae from a suite of ponds on Cape Cod, Massachusetts, U.S.A.

A new species of Mallomonas, M. nieringii sp. nov., is described from a small, poorly buffered, acidic locality on Cape Cod, Massachusetts, U.S.A. Cells are covered with uniquely sculptured scales, each scale of which may possess a single bristle. Cell, scale and bristle morphology all indicate that this new species should be placed within the series Punctiferae of the section Punctiferae, which now has four recognized species and one variety. Scales of the apical ring are highly asymmetric in design, each with a forward projecting triangular shaped spine. Collectively, the triangular shaped extensions of the apical ring of scales surround a single emergent flagellum. Body scales resemble those of Mallomonas punctifera and M. transsylvanica in shape and general morphology, but differ in lacking distinct secondary ribbing on the shield. Mallomonas nieringii was found in six waterbodies all situated within a small geographic area on the outer tip of the Cape Cod peninsula.     

The taxonomy of problematic Mallomonas species (Synurophyceae). I. Mallomonas hindonii and M. canina

Whole cells with complete cell armour (siliceous scales and bristles) of Mallomonas hindonii and Mallomonas canina (Synurophyceae) have been found in Ontario. It is concluded that these two species are not synonymous, as has been suggested previously, and attention is given to structural features of scales and bristles which can be used to distinguish between them. Both species are restricted to softwater/acidic environments.     

The taxonomy of problematic Mallomonas species (Synurophyceae). II. Mallomonas costata and M. galeiformis

Whole cells of Mallomonas costata and Mallomonas galeiformis with complete scale and bristle complements present few problems for their identification by TEM. Individual scales however, such as those usually encountered in paleolimnology, have often been difficult to identify in isolation. Both species occur in collections from Ontario, Canada, but M. galeiformis is apparently more acidophilic than M. costata . Several differences in structure of scales from both species are described which, if used as criteria for distinguishing between the two species, should facilitate identification of individual scales.     

Three new species of Mallomonas (Chrysophyceae, Mallomonadaceae) from Lake Lanalhue, Chile

Three new species of the genus Mallomonas are described. Mallomonas rasilis sp. nov. belongs to the sect. Mallomonas , ser. Papillosae , while M. scalaris sp. nov. and M. lanalhuensis sp. nov. are members of the sect. Torquatae. They were found in Lake Lanalhue, Arauco Province, Chile. The taxonomy and distribution of these species is discussed, along with the morphology of cells, scales and bristles, based on scanning and transmission electron microscopy.     

The tegumental surface of Phyllodistomum conostomum (Olsson, 1876) (Digenea), revealed by scanning electron microscopy

The external surface of P. conostomum is characterized by relatively large ridges encircling the anterior part of the worm at regular intervals. On the posterior part depressions on the ventral side at regular intervals and relatively small ridges on the dorsal side are present. Ventroposteriorally cobblestone-like protuberances observed are arranged in longitudinal rows. No corresponding arrangement was found dorsally. Only domed papillae (with and without a central knob) were observed, tentatively identified as sensory organs. The regular pattern of these papillae on the ventral and oral sucker is described, in addition to their arrangement ventrally and at the anterior end. A frontal pit anterior of oral suckers and a notch at the posterior end are figured and briefly described. No spines were observed on the body tegument.     

Silica-scaled chrysophytes from West Greenland: Disko Island and the Søndre Strømfjord region

The flora of silica-scaled chrysophytes (Chrysophyceae and Synurophyceae) is known from two previous investigations in southern Greenland, from Narssaq (61°N) and Nuuk (64°N).
In connection with a course in Arctic Biology 25.7.-20.8 1990 chrysophyte samples were obtained from altogether 53 localities, 41 from the Godhavn region in Disko Island (69°N) and 12 from S0ndre Str0mfjord (67°N). The localities were lakes, ponds and puddles, on basalt or an acid bedrock. Fixed samples were examined by EM, and altogether twenty species were identified by their silica scales. Eight of these were new to Greenland, viz. Spiniferomonas silverensis, Mallomonas acaroides, M. alpina, M. crassisquama (previous records proved to belong to M. duerrschmidliae), M. oviformis, M. paludosa, M. tonsurata , and Synura mammillosa. The composition of the flora is discussed from ecological and biogeographic viewpoints.     

Mallomonas nuussuaqensis nov. sp., a new species of silica-scaled chrysophytes from West Greenland

A new species of Mallomonas, M. nuussuaqensis was found to be common in samples collected from waterbodies on Nuussuaq/Nûgssuaq (70N-71N, West Greenland). The species has very compact silica scales with a thick broad marginal rim and a very thick and broad hood, which often occupies more than two thirds of the shield.     

A new species of genus <Emphasis Type="Italic">Pseudogyrinocheilus</Emphasis> (Teleostei: Cyprinidae) from Guangxi,China

A new species, Pseudogyrinocheilus longisulcus, was discovered from a tributary of Pearl River in Jingxi Co., Guangxi, China, The new species can be distinguished from other species of Pseudogyrinocheilus by the following combination of characteristics: prolonged post-labial grooves, and extended antero-medially close to anterior end of middle lower lip, but not meeting with its counterpart; posterior margin of lower lip free; scales of abdomen from thorax to pectoral-fin base embedded under skin; lateral-line scales 40–42; dark stripe longitudinal along lateral line on flank. The key to the species of Pseudogyrinocheilus is provided.     

Growth characteristics of three Mallomonas species (silica-scaled chrysophytes) at different temperatures and pH

Three species of Mallomonas ( M. crassisquama , M. elongata and M. tonsurata ) were isolated from Kachang dam in Daegu, Korea and the individual species were grown as batch cultures in the laboratory. The growth characteristics of these species were investigated at different temperatures and pH. Mallomonas crassisquama exhibited the highest growth rates (μ_max) at 18°C, whereas the maximum growth rates of M. elongata and M. tonsurata were observed at 21°C. The maximum growth rates of M. crassisquama and M. elongata were observed at pH 6, and M. tonsurata exhibited maximum growth rate at pH 5. Mallomonas crassisquama and M. tonsurata showed high growth rate between pH 4 and 6, and M. elongata showed high growth rate below pH 7. The three species showed similar growth characteristics except that M. elongata proliferated at a narrower temperature range and at a wider pH range than other two species.     

Chrysophycean scales as paleoindicators in the sediments of Hall Lake, Washington, U.S.A.

Twelve species of Mallomonas and ten species of other genera of Mallomonadaceae and Paraphysomonadaceae were found in sediments deposited in Hall Lake from about 1850 to the present. One Mallomonas species ( M. portue-ferreae peterfi & As-mund) was found that had not previously been reported from North America. The majority of the species have been described as either generally distributed or characteristic of acid or oligotrophic humic waters. M. heterospina Lund and M. multiunca Asmund, which were restricted to sediments deposited during the operation of a sawmill on the lake, have been collected from very eutrophic to dystrophic waters as well. On the whole the species composition indicates a change in the lake from oligotrophic to more eutrophic conditions.