Parachordodes tegonotus n. sp. (Gordioidea: Nematomorpha), a hairworm parasite of ground beetles (Carabidae: Coleoptera), with a summary of gordiid parasites of carabids

A new species of hairworm, Parachordodes tegonotus n. sp. (Gordioidea: Nematomorpha) is described from three species of ground beetles (Carabidae: Coleoptera) from the state of Oregon. This is the first record of Parachordodes Camerano parasitising carabid beetles in North America. Diagnostic characters for the new species include size, colour, the nature and arrangement of the areoles, and the character, shape and extant of ornamentation on the ventral surface of the male tail. Encysted hairworm larvae found in the internal tissues of mayfly and caddisfly larvae at the type-locality were presumed to be those of P. tegonotus, indicating an indirect life-cycle involving paratenic hosts. A worldwide host list shows that some 70 species of ground beetles have been documented as developmental hosts to hairworms belonging to at least five genera, namely Gordius, Parachordodes, Dacochordodes, Gordionus and Paragordionus.     

Variation of cuticular characters in the Nematomorpha: studies on Gordionus violaceus (Baird, 1853) and G. wolterstorffii (Camerano, 1888) from Britain and Ireland

Gordionus violaceus (Baird, 1853) and G. wolterstorffii (Camerano, 1888) are regarded as two species which are clearly separated by distinct cuticular patterns. A study of 59 specimens of these two species from Britain and Ireland revealed numerous transitional stages between the cuticular patterns that are regarded as being typical for each species. Variation was also found at the posterior end, but no character separates both species. Therefore, G. violaceus and G. wolterstorffii might represent one polymorphic species. Four specimens resembled G. violaceus but had a different cuticular pattern, including a second type of areole occurring in a pattern which has been named a megareolar pattern. This might represent a separate species, but a detailed determination relies upon further revisional work in the genera Gordionus, Parachordodes and Paragordionus.     

Gordionus maori (Nematomorpha: Gordiida), a new species of horsehair worm from New Zealand

Only four species of freshwater Nematomorpha (Gordiida) and one undetermined Gordius sp. are known from New Zealand. During recent surveys in the South Island we discovered a new species belonging to the genus Gordionus, a genus new to New Zealand. Scanning electron microscopic observations of seven collected specimens revealed that the species is clearly morphologically distinct from all other members of the genus and is characterised by the presence of an extensive row of large bristles on the ventral side of the posterior end in males. This row is much larger than in any known Gordionus species. Analysis of the mitochondrial CO1 gene and of the nuclear 18S rRNA gene showed that the new Gordionus specimens form a monophyletic clade, but with partly extensive internal genetic difference. This indicates that cryptic species might be present, for although there are minor variations in cuticular areoles, other morphological characters indicate little difference between specimens.

LSID urn:lsid:zoobank.org:pub:E6E436C0-9032-4D4B-B08C-1C7B6948291A     

Gymnomeropsylla n. gen. (Siphonaptera: Pygiopsyllidae) from Sulawesi,Indonesia, with the description of two new species

Compared to related genera, this new flea genus is characterized by the absence, or presence of very few, bristles on the external surface of femur I and especially by the morphology of the apex of sternite IX in the male, which is hyaline and lacks spiniform bristles. The two new species, G. bunomydis and G. margaretamydis, are distinguished from each other by the structure of the genitalia, and the presence of numerous erect bristles on the thorax and abdominal tergites of the latter species. Both of these new species parasitize murine rodents that are endemic to Sulawesi; G. bunomydis was collected mainly from Bunomys chrysocomus and G. margaretamydis only from Margaretamys parvus.     

Dujardinascaris spp. (Nematoda: Ascaridoidea) in Old World crocodilians

Five new species of the genus Dujardinascaris Baylis, 1947 are described from Old World crocodilians: D. petterae n. sp. in Osteolaemus tetraspis from the Congo, Central Africa; D. blairi n. sp in Crocodylus johnstoni from Northern Australia; D. harrisae n. sp., D. angusae n. sp., and D. westonae n. sp. in C. porosus from Papua New Guinea. The species are differentiated by the relative length of the spicules, the shape of the gubernaculum and the form of the male tail. Females of the species cannot be readily distinguished morphologically.     

Diversity and Distributional Patterns of Neotropical Freshwater Copepods (Calanoida: Diaptomidae)

The distributional patterns and diversity of the diaptomid calanoid copepods were analysed to assess the faunistic affinity of North and South America with respect to Mexico and Central America. In the Neotropical region, the most speciose genera of Diaptomidae are Leptodiaptomus and Mastigodiaptomus. The former genus is a Nearctic form, and Mastigodiaptomus is Neotropical. Based on the current distribution of their diversity, it is probable that these genera radiated into Mexico and Central America from North America and the insular Caribbean, respectively. Arctodiaptomus dorsalis is a primarily Palaearctic taxon, it is widely distributed between North and Central America. This species probably radiated in the Americas as a Tethyan derivate. Prionodiaptomus is the only member of the highly diverse South American diaptomid fauna that has expanded beyond the subcontinent. Despite the high diversity present in South America, its influence in Mexico and Central America appears to be weak; this is probably a consequence of the geologically recent union of the two main subcontinental landmasses. Mexico shares 33% of its species with NA, and no species are shared between NA and SA. For the Diaptomidae, the Nearctic influence is strongest in Mexico. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Phytogeography of the trees of the Osa Peninsula,Costa Rica

A phytogeographic analysis of the distributions of 454 species of trees native to the Osa Peninsula in 22 families revealed that 4.8% of the species are endemic to the Osa Peninsula and the adjacent mainland of Costa Rica. However, nearly one-fourth of the species might be regionally endemic to Central-South Mesoamerica (Costa Rica, Nicaragua, and Panama). Our sample suggests that 53.6% of the species occur in some part of Mesoamerica and sometimes range into northwestern South America, and that 44.5% of the species have wide distributions throughout tropical America. There is a strong affinity with the flora of northwestern South America, with 46.2% of the species on the Osa also found there. In addition, 50.6% of the tree species on the Osa occur on both the Atlantic and Pacific slopes of Central America or, if they reach South America, are sometimes found on both sides of the Andes. Major contributions to the tree flora of the Osa have been made by species arriving in the Osa by 1) dispersal from South and North America to islands in proto Central America before the formation of a dry-land connection between the two continents, and 2) migration from South America and North America after the closure of the Panamanian isthmus was made. This analysis demonstrates the importance of the Osa as a regional refuge for protecting species with distributions limited to the Osa and parts of Panama, Costa Rica, or Nicaragua. The Osa is also important because it harbors the last expanse of tropical wet forest on the Pacific slope of Central America large enough to ensure the survival of the Central American populations of widely distributed plants and animals.     

Biogeography of mutualistic fungi cultivated by leafcutter ants

Leafcutter ants propagate co‐evolving fungi for food. The nearly 50 species of leafcutter ants (Atta, Acromyrmex) range from Argentina to the United States, with the greatest species diversity in southern South America. We elucidate the biogeography of fungi cultivated by leafcutter ants using DNA sequence and microsatellite‐marker analyses of 474 cultivars collected across the leafcutter range. Fungal cultivars belong to two clades (Clade‐A and Clade‐B). The dominant and widespread Clade‐A cultivars form three genotype clusters, with their relative prevalence corresponding to southern South America, northern South America, Central and North America. Admixture between Clade‐A populations supports genetic exchange within a single species, Leucocoprinus gongylophorus. Some leafcutter species that cut grass as fungicultural substrate are specialized to cultivate Clade‐B fungi, whereas leafcutters preferring dicot plants appear specialized on Clade‐A fungi. Cultivar sharing between sympatric leafcutter species occurs frequently such that cultivars of Atta are not distinct from those of Acromyrmex. Leafcutters specialized on Clade‐B fungi occur only in South America. Diversity of Clade‐A fungi is greatest in South America, but minimal in Central and North America. Maximum cultivar diversity in South America is predicted by the Kusnezov–Fowler hypothesis that leafcutter ants originated in subtropical South America and only dicot‐specialized leafcutter ants migrated out of South America, but the cultivar diversity becomes also compatible with a recently proposed hypothesis of a Central American origin by postulating that leafcutter ants acquired novel cultivars many times from other nonleafcutter fungus‐growing ants during their migrations from Central America across South America. We evaluate these biogeographic hypotheses in the light of estimated dates for the origins of leafcutter ants and their cultivars.     

The shape of a species' spatial abundance distribution

Aim The shape of a species' spatial abundance distribution may change with spatial scale. We predict that the shape will typically change from strictly downward‐sloping (falling) to humped (rising then falling) as the spatial scale increases. The prediction, motivated in part by central limit reasoning, is intended for common or abundant species over reasonably homogeneous habitats. We test the prediction using data on 800+ tree species, one ant species, and 14 bird species. Location Tree data are for Malaysia and Central America; ant and bird data are for North America. Methods For each species, histograms and relative mode shape statistics are compared across multiple spatial scales. Results The predicted pattern is broadly confirmed. Main conclusions The emerging hump pattern is a candidate for listing among macroecological regularities. In appropriate contexts, spatial theories might be asked to predict the pattern.     

Micro morphological Characteristics of Leaf Epidermis under Light Microscopy and Its Taxonomic Significance in Persea (Lauraceae) from America

Leaf epidermal micro morphological characters of 54 species belonging to genus Persea (Lauraceae) from America were comparatively studied by the means of light microscopy. It was shown that the leaf epidermal cells were usually regular bearing with straight or beaded anticlinal walls.Most of these species had unicellular trichomes uniformly distributed. The stomatal apparatus which were paracytic, only randomly presented in the areoles of abaxial epidermis for all sampled species, can be assigned into three types. The results showed that similar leaf epidermal characters can be found in the species with similar morphology. Nineteen characters were selected for PCA analysis, and the sampled species was divided into two clades. The characters of leaf epidermis were little different within a species but can vary among species. However, the multiple leaf epidermal characters including the shape of epidermal cells, the shape of stomatal apparatus, stomatal ledges and some distinct characters were relatively constant and taxonomically quite useful for the identification of some species with similar phenotypes.     

Cuticular ultrastructure of Chordodes nobilii Camerano, 1901, with a comparison of cuticular ultrastructure in horsehair worms (Nematomorpha)

The cuticle of Chordodes nobilii Camerano, 1901 is composed of a proximal layer with about 30 sheets of large fibers in alternating orientations and a distal layer, which mainly forms the surface structures, the areoles. The three different types of areoles, simple, tubercle and crowned areoles, are formed mainly by material of strong and medium electron density. The tubercle areoles have a basal constriction and paired spherical structures of unknown function below the base. Irregularly distributed are paired, cushion-like structures, from which projections traverse the cuticle and run into the epidermis. In the crowned areoles, these cushions also send projections into the apical filaments. A comparison with the few ultrastructurally described cuticles from other species reveals some similarities between the cuticles of C. nobilii and Paragordius varius, making it probable that the cushion-like structures are homologous. However, Pseudochordodes bedriagae, which is more closely related to Chordodes than Paragordius, lacks the cushions. Problematic is the interpretation of different cuticular structures in Gordius. If correctly determined, areoles are present in some Gordius species and resemble in their structure areoles from other species. If areoles have to be regarded as homologous, the absence of a distal layer and areoles would have to be interpreted as a secondary reduction in species such as Gordius aquaticus.     

Allopodocotyle chiliticorum n. sp. (Digenea: Opecoelidae) from redlip shiners, Notropis chiliticus, in Basin Creek, North Carolina

Allopodocotyle chiliticorum n. sp. is described from the intestines of redlip shiners (Notropis chiliticus) from Basin Creek, North Carolina. The new species is characterized by circumcecal vitelline fields that are not confluent in the post-testicular space, which distinguishes it from the 3 previously known species of this genus described from freshwater fishes. The new species is characterized further by an elongate vitelline reservoir lying dorsal to the ovary, an ovary as large or larger than the testes, and an excretory vesicle not reaching the posterior testis. A. chiliticorum n. sp. most closely resembles Allopodocotyle lepomis (Dobrovolny, 1939) in body shape, testes shape, and terminal genitalia but is distinguished further from this species by the extent of the intestinal ceca. The new species is the fourth species of Allopodocotyle known from freshwater fishes in North America.     

美洲鳄梨属植物的叶表皮微形态特征及其分类学意义

在光学显微镜下,对美洲鳄梨属54种植物的叶表皮微形态特征进行了观察,研究发现叶表皮细胞形状多为规则形;垂周壁一般平直;大多数种类的叶表皮具均匀分布的单细胞毛状体;平列型气孔器下生,随机分布于网状叶隙内,可进一步分为3个小类;形态相似的物种通常具有相似的叶表皮特征。本研究选取了19个特征进行PCA分析,发现鳄梨属被明显分为2个支系。叶表皮特征在种内比较稳定,种间存在一定差异,表皮细胞形状、气孔器形态及其突出物等特征组合对于鳄梨属种尤其一些表型相似的种类的鉴定有一定的帮助。     

Looking at both sides of the invasion: patterns of colonization in the violet tunicate Botrylloides violaceus

Understanding the ecological and evolutionary forces that shape the genetic structure of invasive populations and facilitate their expansion across a large spectrum of environments is critical for the prediction of spread and management of ongoing invasions. Here, we study the dynamics of postestablishment colonization in the colonial ascidian Botrylloides violaceus, a notorious marine invader. After its initial introduction from the Northwest Pacific, B. violaceus spread rapidly along the Pacific and Atlantic coasts of North America, impacting both aquaculture facilities and natural ecosystems. We compare genetic diversity and patterns of gene flow among 25 populations (N=679) from the West and East coasts, and evaluate the contribution of sexual vs. asexual reproduction to this species' invasion success using data from the mitochondrial cytochrome c oxidase subunit I (COI) gene and 13 nuclear polymorphic microsatellite loci. Our results reveal contrasting patterns of spread in the coastal waters of North America. While the West coast was colonized by noncontiguous (long-distance) dispersal, the East coast invasion appears to have occurred through contiguous (stepping-stone) spread. Molecular data further indicate that although dispersal in colonial ascidians is predominantly achieved through sexually produced propagules, aquaculture practices such as high-pressure washing can facilitate fragmentation and potentially exacerbate infestations and spread via asexual propagules. The results presented here suggest that caution should be used against the general assumption that all invasions, even within a single species, exhibit similar patterns of colonization, as highly contrasting dynamics may transpire in different invaded ranges.     

The biogeography of Gunnera L.: vicariance and dispersal

Aim The genus Gunnera is distributed in South America, Africa and the Australasian region, a few species reaching Hawaii and southern Mexico in the North. A cladogram was used to (1) discuss the biogeography of Gunnera and (2) subsequently compare this biogeographical pattern with the geological history of continents and the patterns reported for other Southern Hemisphere organisms. Location Africa, northern South America, southern South America, Tasmania, New Zealand, New Guinea/Malaya, Hawaii, North America, Antarctica. Methods A phylogenetic analysis of twenty‐six species of Gunnera combining morphological characters and new as well as published sequences of the ITS region, rbcL and the rps16 intron, was used to interpret the biogeographical patterns in Gunnera. Vicariance was applied in the first place and dispersal was only assumed as a second best explanation. Results The Uruguayan/Brazilian Gunnera herteri Osten (subgenus Ostenigunnera Mattfeld) is sister to the rest of the genus, followed sequentially upwards by the African G. perpensa L. (subgenus Gunnera), in turn sister to all other, American and Australasian, species. These are divided into two clades, one containing American/Hawaiian species, the other containing all Australasian species. Within the Australasian clade, G. macrophylla Blume (subgenus Pseudogunnera Schindler), occurring in New Guinea and Malaya, is sister to a clade including the species from New Zealand and Tasmania (subgenus Milligania Schindler). The southern South American subgenus Misandra Schindler is sister to a clade containing the remaining American, as well as the Hawaiian species (subgenus Panke Schindler). Within subgenus Panke, G. mexicana Brandegee, the only North American species in the genus, is sister to a clade wherein the Hawaiian species are basal to all south and central American taxa. Main conclusions According to the cladogram, South America appears in two places, suggesting an historical explanation for northern South America to be separate from southern South America. Following a well‐known biogeographical pattern of vicariance, Africa is the sister area to the combined southern South America/Australasian clade. Within the Australasian clade, New Zealand is more closely related to New Guinea/Malaya than to southern South America, a pattern found in other plant cladograms, contradictory to some of the patterns supported by animal clades and by the geological hypothesis, respectively. The position of the Tasmanian G. cordifolia, nested within the New Zealand clade indicates dispersal of this species to Tasmania. The position of G. mexicana, the only North American species, as sister to the remaining species of subgenus Panke together with the subsequent sister relation between Hawaii and southern South America, may reflect a North American origin of Panke and a recolonization of South America from the north. This is in agreement with the early North American fossil record of Gunnera and the apparent young age of the South American clade.     

Variations in the arrangement of sensory bristles along butterfly wing margins

The surfaces of insect wings exhibit numerous sensilla, which have been suggested to have a behavioral function. Some evidence suggests that the sensory bristles along the wing margin of lepidopteran insects (butterflies and moths) are involved in the regulation of wing movement. We investigated the arrangement of sensory bristles along the wing margins of 62 species of papilionoid butterflies, using light-microscopic examination of mounts of whole wings after removing the scales surrounding the bristles. In the majority of the wings examined, bristles were located on the ventral wing surfaces and were continuously distributed along the wing margins, except in the vicinity of the wing bases. In some wings, bristles were also located on the dorsal wing surfaces, and were continuously or discontinuously distributed along the wing margins of different species. In a minority of the species studied, we observed bristle distribution in the vicinity of the wing base, discontinuous bristle distribution on both the dorsal and ventral wing surfaces, or an absence of bristles along the wing margins. This variation in the arrangement of bristles along the wing margins is discussed in relation to the reception and transmission of sensory information in the wings.     

A taxonomic study of campylopus schimperi and C. subulatus (Bryopsida: Dicranaceae) in North America

Campylopus schimperi is known in North America from Oaxaca, Colorado, British Columbia, Yukon, Alaska, Baffin Island, Gaspé Peninsula, and Newfoundland, and reported from Greenland. No specimens of the previously reported C. subulatus were found from North America and this species should be excluded from the North American bryophyte flora. A quantitative study and critical review of the characters distinguishing these two species indicate that leaf laminal cell shape and length, and costal anatomy are the most definitive taxonomic features. The distributional range of C. schimperi in North America suggests a close association with unglaciated areas and hypothesized glacial refugia.