Diversity and distribution of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) in Turkey

The diversity and distribution of entomopathogenic nematodes in thefamilies Steinernematidae and Heterorhabditidae were assessed throughout anextensive soil survey in Turkey during 1999 and 2000. Entomopathogenic nematodeswere recovered from six out of seven regions sampled, with 22 positive sites(2%) out of 1080 sites sampled. A single nematode isolate was recovered at eachof the positive sites, of which 15 were steinernematid isolates and seven wereheterorhabditid isolates representing a total of four species. Based onmorphometric and molecular data, the nematode species were identified asHeterorhabditis bacteriophora, Steinernemafeltiae, S. affine, andSteinernema n. sp. The most common species was S.feltiae, which was isolated from 10 sites in six regions, followed byH. bacteriophora from seven sites in five regions,S. affine from four sites in two regions, andSteinernema n. sp. from one site. Heterorhabditisbacteriophora and S. feltiae have been found inmany parts of the world, whereas S. affine, so far, hasonly been recovered in Europe until our survey. Steinernemaaffine was isolated from the European (Marmara) as well as theAsiatic region (Middle Anatolia) of Turkey. A new undescribedSteinernema sp. was isolated from the most eastern region(East Anatolia) of Turkey. Soils of the positive sites were classified as sandy,sandy loam, or loam (68.2%) and sandy–clay–loam or clay loam (31.8%) and the pHranged from 5.6 to 7.9. The habitats from which the entomopathogenic nematodeswere isolated were broadly classified as disturbed (59.1%), which includedagricultural fields and poplar planted for lumber and wind breaks, andundisturbed (40.9%), which included pine forest, grassland, marsh and reed sites.Steinernema feltiae, S. affine, andH. bacteriophora were recovered from both disturbed andundisturbed habitats. The new Steinernema sp. was recoveredfrom grassland. Our survey showed that these nematodes occur widely throughoutTurkey, but at a frequency below that reported for other parts of the world.     

Helminth associations in white-toothed shrews Crocidura russula (Insectivora: Soricidae) from the Albufera Natural Park, Spain

The helminths of 218 white-toothed shrews from 29 sites in 2 biotopes in the Albufera Natural Park (Valencia, Spain) were examined from July 1990 to August 1991. An association analysis of helminths occurring at a prevalence of more than 4% was carried out for 4 species of cestodes located in the intestine (Hymenolepis pistillum, H. scalaris, H. tiara, and Pseudhymenolepis redonica) and 3 species of nematodes (Pseudophysaloptera sp. located in the stomach, Stammerinema rhopocephala larvae in the intestine and abdominal cavity, and Porrocaecum sp. in the thoracic and abdominal cavities). Bivariate (species pairs) versus multivariate analyses (associations within the entire set of species) were performed of presence-absence and of quantitative records (influence of intensity on associations). The associations were evaluated with respect to the sex and age of the host and to the sampling date and sites. The host and environment played a limited role, and the major determinant of species assemblage was phylogenetic. Positive associations were found among both the cestodes and the nematodes, whereas negative associations were found between cestodes and nematodes. The type of life cycle was probably the second greatest determinant of species associations. Nematodes using shrews as a paratenic host or as their definitive host were both positively associated.     

Temporal and spatial dynamics of competitive parapatry in chewing lice

We synthesize observations from 1979 to 2016 of a contact zone involving two subspecies of pocket gophers (Thomomys bottae connectens and T. b. opulentus) and their respective chewing lice (Geomydoecus aurei and G. centralis) along the Río Grande Valley in New Mexico, U.S.A., to test predictions about the dynamics of the zone. Historically, the natural flood cycle of the Rio Grande prevented contact between the two subspecies of pocket gophers. Flood control measures completed in the 1930s permitted contact, thus establishing the hybrid zone between the pocket gophers and the contact zone between their lice (without hybridization). Since that time, the pocket gopher hybrid zone has stabilized, whereas the northern chewing louse species has replaced the southern louse species at a consistent rate of ~150 m/year. The 0.2–0.8 width of the replacement zone has remained constant, reflecting the constant rate of chewing louse species turnover on a single gopher and within a local pocket gopher population. In contrast, the full width of the replacement zone (northernmost G. centralis to southernmost G. aurei) has increased annually. By employing a variety of metrics of the species replacement zone, we are better able to understand the dynamics of interactions between and among the chewing lice and their pocket gopher hosts. This research provides an opportunity to observe active species replacement and resulting distributional shifts in a parasitic organism in its natural setting.     

AGE AND MOVEMENT OF A HYBRID ZONE: IMPLICATIONS FOR DISPERSAL DISTANCE IN POCKET GOPHERS AND THEIR CHEWING LICE

Historical flood records for the Rio Grande Valley of New Mexico suggest that a pocket gopher (Thomomys bottae) hybrid zone previously thought to be 10,000 years old may actually be closer to 50 years old. Measured zone width (defined genetically) is consistent with the hypothesis of recent contact, if we assume a reasonable dispersal distance of approximately 400 m/year for pocket gophers. A five-year study of movement of the contact zone between the two species of chewing lice that parasitize these pocket gophers also is consistent with the hypothesis of recent origin of the zone.     

Responses of pocket gophers (Thomomys bottae) to changes in diet quality

Summary We examined digestibility of dry matter, nutrients, and fiber, and food intake, metabolic fecal losses, weight change, and gut size of pocket gophers (Thomomys bottae) in relation to diet quality in the laboratory. Pocket gophers were maintained for 15–20 days on one of seven diets which contained from 18% to 56% neutral detergent fiber (NDF). NDF content of the diet was an excellent predictor of diet quality. Digestibility of dry matter, NDF, and nitrogen all decreased with increasing NDF content of the diet. In general, pocket gophers compensated for low diet quality by increasing dry matter intake, but those given high quality forage before the lowest quality diet reduced their intake. Thus, the response of pocket gophers to low quality diets may depend on their body condition. Because increased food intake resulted in increased total metabolic fecal losses and metabolic fecal nitrogen losses, decreasing food intake on low-quality diets may be advantageous. A further response of pocket gophers to decreased food quality was an increase in size of cecum and large intestine, suggesting that fermentation of cell walls became increasingly important as diet quality decreased.     

Evolutionary and ecological response of pocket gophers (Thomomys talpoides) to late-Holocene climatic change

Late-Holocene evolutionary and ecological response of pocket gophers ( Thomomys talpoides ) and other species to climatic change is documented by mammalian fossils from Lamar Cave, a palaeontological site in northern Yellowstone National Park. Pocket gophers illustrate ecological sensitivity to a series of mesic to xeric climatic excursions in the sagebrush-grassland ecotone during the last 3200 years, increasing in abundance during mesic intervals, and declining in abundance during xeric intervals. Four other small mammal taxa (Microtus sp., Peromyscus maniculatus, Neotoma cinerea and Spermophilus armatus) also show response to climatic change, increasing or decreasing in abundance in accordance with their preferred habitat requirements. To determine evolutionary response to climate, two craniodental characters for the northern pocket gopher ( Thomomys talpoides ) are investigated in modern representatives within a 400 km radius of Lamar Cave and then tracked through the time spanned by the fossils. One morphologic character shows that variation in body size, primarily a plastic response to the environment, demonstrates few taxonomically consistent patterns of geographic variation across 39 modern localities. In contrast, the other character indicates genetic relatedness within subspecies. Stasis in the genetically controlled character indicates that the same subspecies of pocket gopher ( T. talpoides tenellus ) has occupied northern Yellowstone for at least 3200 years. However, T. t. tenellus does show plastic response to climatic change because pocket gophers during the Medieval Warm Period were smaller than at any other time spanned by the deposit.     

Three new species of Tricorythopsis (Ephemeroptera: Leptohyphidae) from southeastern Brazil

Three new species of Tricorythopsis Traver (Ephemeroptera: Leptohyphidae) are described and illustrated based on nymphs from southeastern Brazil. These new species can be distinguished from other species of the genus by the following characters: Tricorythopsis araponga sp. n.: (1) femora with long setae; (2) abdominal segments 5–7 with dorsal tubercles; (3) tarsal claws with 4–6 marginal denticles and 7 + 4 submarginal denticles. Tricorythopsis baptistai sp. n.: (1) tarsal claws with 4–5 large marginal denticles and one submarginal denticle on each side; (2) abdominal colour pattern; (3) abdomen without tubercles; (4) coxae without projections. Tricorythopsis pseudogibbus sp. n.: (1) abdominal segments 6–8 with small dorsal tubercles; (2) tarsal claws with four large marginal denticles, and 3 + 1 or 2 submarginal denticles; (3) coxae dorsally projected; (4) femora broad and with short setae; (5) pronotum with anterolateral projection.     

Carnoya kermarreci n.sp. (Rhigonematidae: Nematoda) from Anadenobolus politus (Porat) (Rhinocricidae: Diplopoda) from Guadeloupe

Summary Carnoya kermarreci n.sp. (Rhigonematidae; Nematoda) is described from Anadenobolus politus (Porat) (Rhinocricidae; Diplopoda) from Guadeloupe. The new species most closely resembles C. martiniquensis Adamson, 1984 from A. politus in Martinique and C. venezuelensis Adamson, 1984 from Rhinocricus flavocinctus from Venezuela in that the lips in the male are broad and the arrangement of caudal papillae is almost identical in the three species. Males of C. kermarreci are easily distinguished by the absence of spines, by the form of the cuticular projections at the base of the buccal cavity and by the fact that the most anterior pair of caudal papillae are located very close together. Females are distinguished by the presence of three pairs of somatic papillae near the level of the vulva. The nematode fauna of A. politus includes species from two distinct orders and presumably reflects the fact that diplopods are among the most ancient hosts of nematodes.     

First record of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) in Costa Rica

A survey of entomopathogenic nematodes was conducted in the north Pacific (Guanacaste Conservation Area) and southeast Caribbean (Gandoca-Manzanillo Natural Refuge) regions of Costa Rica. Out of a total of 41 soil samples, 5 were positive for entomopathogenic nematodes (20.5%), with 3 (12.3%) containing Steinernema and 2 (8.2%) Heterorhabditis isolates. Morphological and molecular studies were undertaken to characterize these isolates. The Heterorhabditis isolates were identified as Heterorhabditis indica and the three Steinernema isolates were identified as two new undescribed species. H. indica was recovered from a coastal dry forest. Steinernema n. sp. 1 was isolated from a rainforest valley, between volcanoes. Steinernema sp. n. 2 was isolated from sand dunes in the Caribbean Coast (Punta Uva) near the rainforest strip along the coast. Although limited to two geographic regions, this study suggests entomopathogenic nematodes may be diverse and perhaps widely distributed in Costa Rica. A more intensive survey, covering all geographic regions is currently undergoing.     

Thaumamermis cosgrovei n. gen., n. sp. (Mermithidae: Nematoda) parasitizing terrestrial isopods (Isopoda: Oniscoidea)

Summary A new mermithid nematode, Thaumamermis cosgrovei n. gen., n. sp. (Mermithidae: Nematoda) was found parasitizing two terrestrial isopods (Isopoda: Oniscoidea) in California. The hosts, Armadillidium vulgare (Latr.) (a pillbug) and Porcellio scaber (Latr.) (a sowbug) represent the first cases of isopods attacked by mermithid nematodes. The genus Thaumamermis can be distinguished from all previously described mermithids by the extremely dimorphic spicules, one being short and broad and the other long and filiform. It has been discovered that the nematodes are infected with an iridiovirus which commonly destroys the isopod hosts. ac]19800917     

Helminth parasites of unisexual and bisexual whiptail lizards (Teiidae) in North America. I. The Colorado checkered whiptail (Cnemidophorus tesselatus)

Eleven of 27 (41%) parthenogenetic Colorado checkered whiptails (Cnemidophorus tesselatus) from four counties of western and southwestern Texas were infected with one or more helminths. These included a linstowiid cestode (Oochoristica sp.), a larval spirurid nematode (Physaloptera sp.) and two species of oxyurid nematodes (Parathelandros texanus and Pharyngodon warneri). This note, the first in a series of reports on helminths of Cnemidophorus spp., represents the first record of parasites from C. tesselatus.     

Ceratomyxa hungarica n. sp. and Chloromyxum proterorhini n. sp. (Myxozoa: Myxosporea) from the freshwater goby Proterorhinus marmoratus (Pallas)

When studying the parasite fauna of freshwater gobies Proterorhinus marmoratus collected from the reaches of the River Danube around Budapest, two species of Myxosporea were recovered, a renal and a gall-bladder form. Previously no myxosporeans had been reported from this fish species. The spores and pseudoplasmodia of the parasite described as Ceratomyxa hungarica n. sp. were found in the convoluted tubules of the kidney and in the cavity of Bowman's capsule. The pseudoplasmodia were loosely attached to the wall of the tubules, causing their distention. Within each pseudoplasmodium two spores were formed. In the case of Chloromyxum proterorhini n. sp. only spores floating freely in the contents of the gall-bladder were found. Since Ceratomyxa species are typically marine fish parasites, Proterorhinus marmoratus, a fish species which has adapted to freshwater, appears to have retained some of its marine myxosporean fauna.     

Two new species of <Emphasis Type="Italic">Aphelenchoides</Emphasis> (Nematoda: Aphelenchida: Aphelenchoidea: Aphelenchidae) from Manipur,India

Analysis of the soil samples collected from around rhizospheric region of mulberry plants grown in Yurembam Rose Garden, Yurembam, Imphal West, Manipur yielded several soil and plant parasitic nematodes. Among them four species of Aphelenchoides were recorded. Upon detailed study, two species of Aphelenchoides were found to be new to science. Aphelenchoides dhanachandi sp. n. is characterized by ventrally curved body, clearly set off cephalic region and tail ending into a sharp pointed terminus, and stylet slender, 13.6–15.3 (14 ± 0.7) μm long with indistinct basal swellings and tamarind seed-shaped median bulb. Aphelenchoides neoechinocaudatus sp. n. is characterized by straight body with four incisures in the lateral field, flatten cephalic region, slender stylet with indistinct basal swellings, 11.9 μm long, elongated pear-shaped median bulb and short tail with pointed mucro. The two species are illustrated here.     

Rhinoclemmysnema n. g. and three new species of nematodes of the family Atractidae (Cosmocercoidea), with notes on the helminth fauna of Rhinoclemmys pulcherrima (Testudines: Bataguridae) in Costa Rica

Rhinoclemmysnema n. g. and three new species of atractid nematodes, namely, Atractis costaricaensis n. sp., Orientatractis asymmetrica n. sp. and Rhinoclemmysnema multilabiatum were recovered from the small and large intestine of Rhinoclemmys pulcherrima, the painted wood turtle in the Guanacaste Conservation Area, Costa Rica. The genera and three species are characterized by the features of the cephalic region and male tail. Neopolystoma fentoni (conjuctival sac) and Heronimus mollis (lungs) were also collected.     

Tetrameres (Gynaecophila) aspicula n. sp. (Nematoda: Tetrameridae), a proventricular parasite of the white-faced ibis Plegadis chihi in Argentina

Tetrameres (Gynaecophila) aspicula n. sp. is described from the proventriculus of the white-faced ibis Plegadis chihi (Vieillot) (Ciconiiformes, Threskiornithidae) from Argentina. The new species is characterised by the absence of spicules, by possessing two ventral rows of extremely small spines in males, extending along the second half of body length, and by the tiny, very feebly developed postcloacal papillae. T. (G.) aspicula n. sp. is compared to the remainder of the species in the subgenus as well as to other species of Tetrameres which lack or possess feebly developed spines. The absence of spicules is a character shared with two other species in the genus, T. (G.) gynaecophila and T. (G.) deccani,from which the new species differs in body size, the arrangement of caudal papillae and the somatic spination in males. A pair of somatic papillae, previously unreported in species of this genus, was found just on or ventral to the lateral line at various regions of the body length. The homology of these structures to other paired somatic papillae described in nematodes is discussed.     

Morphological constraints in the digging apparatus of pocket gophers (Mammalia: Geomyidae)

The digging apparatus of pocket gophers offers a unique opportunity to examine morphological constraints within a historical context because relationships among extant taxa are well resolved and the features enhancing digging performance are relatively well understood. Structural and functional considerations suggest that the muscles associated with tooth- and claw-digging in pocket gophers are subjected to contrasting levels of morphological constraints. To assess this hypothesis, we analysed the bones and muscles of the jaws and forelimbs in four genera comprising five species of pocket gophers. Morphometric analyses were performed on 12 osteological measurements selected to reflect overall skull size, variation in rostral shape and procumbency, differences in overall length of the forelimbs and processes relating to the function of lever systems used in claw-digging. In addition, dissections were made of the jaw, hyoid, neck and all of the forelimb muscles excluding the intrinsic muscles of the manus. Results of our morphometric analyses corroborate the recent suggestion that pocket gophers encompass a wide range of morphological variation extending from claw-diggers to tooth-diggers. Myologically, however, we found structural variation only in the forelimb muscles, some of which may be advantageous for digging. No changes in jaw, neck and hyoid muscles, other than differences in muscle mass or those concordant with differences in rostral shape, were noted. These results support our hypothesis that constrasting levels of morphological constraint exist between the jaw and forelimb muscles of pocket gophers. We present a discussion of the structural and functional constraints on jaws and forelimbs in gophers as well as an analysis of historical constraints acting on this group, and perhaps on mammals in general.     

<Emphasis Type="Italic">Aulacnema monodelphis</Emphasis> n. g., n. sp. and <Emphasis Type="Italic">Angiostoma coloaense</Emphasis> n. sp. (Nematoda: Rhabditida: Angiostomatidae) from terrestrial molluscs of Vietnam

Two species of nematodes, Angiostoma coloaense n. sp. and Aulacnema monodelphis n. g., n. sp. (Angiostomatidae: Rhabditida) are described from terrestrial molluscs of Vietnam. Both species are characterised by a long bowl-shaped buccal cavity and typically angiostomatid male bursal alae, spicules and gubernaculum. The new genus, Aulacnema n. g., is erected for the first reported monodelphic angiostomatid. Angiostoma coloaense n. sp. can be distinguished from other species of Angiostoma Dujardin, 1845 by having a buccal cavity length greater than its width and the absence of tail spikes on both males and females.     

Nematodes associated with Ips cembrae (Coleoptera: Curculionidae): comparison of generations,sexes and sampling methods

A study of nematodes associated with the large larch bark beetle Ips cembrae (Heer 1836) was carried out at three locations in the Czech Republic. The proportion of beetles infested by endoparasitic nematodes (representatives of genera Contortylenchus, Parasitylenchus, Cryptaphelenchus and Parasitorhabditis) ranged from 29.9 to 50.9%. Significant differences were determined in nematode infestation levels among locations, generations and sampling methods. No differences were found in infestation rates between males and females. The percentage of bark beetles with phoretic nematodes ranged from 18 to 42.9%. Phoretic nematodes directly found under elytra, on wings and between body segments of the bark beetles belong to the genus Micoletzkya. However, adults and juveniles of other two phoretic species Laimaphelenchus penardi and Bursaphelenchus sp. were found in the gallery frass of I. cembrae. Infestation by phoretic nematodes positively correlated with the presence of mites under elytra.     

New deep-sea Nematoda (Enoplida,Thoracostomopsidae, Oncholaimidae,Enchelidiidae) from a manganese nodule area of the eastern South Pacific*

Five new nematode species are described from a mangancsc nodule area of the abyssal eastern South Pacific: Enoploides tyrannis sp. n., Paramesacanthion abyssorum sp. n., P. forcepssp. n. (all three Thoracostomopsidae), Phylloncholaimus immanis gen. et sp. n. (Oncholaimidac), and Eurystomina absoluta sp. n. (Enchelidiidae). They are characterized by large size (body length 5000–23000 μm), short tails (c = 17–33), and strongly cuticularizcd, barrel-shaped buccal cavities with large teeth. With the exception of one male of E. tyrannis from the surface of a manganese nodule, all other specimens were found in the sediment. The new species are sporadic in distribution and represented by few individuals.