Americana Gmelin Research Articles

A new feather mite species of the genus Temnalges (Acariformes: Psoroptoididae) from coots, Fulica spp. (Gruiformes: Rallidae)

A new feather mite species, Temnalges fulicae sp. n. (Psoroptoididae: Pandalurinae), is described from two species of coots, Fulica americana Gmelin, 1789 (type host), in Canada, and F. atra Linnaeus, 1758, in Denmark. The new species is close to other species of the genus associated with rails (Rallidae), especially to T. megalonyx Gaud, 1968, in having a long spur-like process on tibia III in males, and the prodorsal and hysteronotal shields separated by a wide area of striated tegument in females. Males of Temnalges fulicae are most clearly distinguished from T. megalonyx in having the opisthosoma rounded and without terminal and lateral clefts, and the adanal shields narrow and short. In females, the prodorsal shield has a convex posterior margin, the hysteronotal shield is roughly rectangular, and setae 4a extend to the bases of setae ps3. Additionally, we provide a world checklist and a key to Temnalges species.

Revision of the species of the genus Diorchis Clerc, 1903 (Cestoda, Hymenolepididae) from rallid birds: a redescription of Diorchis acuminata (Clerc, 1902).

The type-species of the genus Diorchis Clerc, 1903, D. acuminata (Clerc, 1902) Clerc, 1903, is re-described and illustrated on the basis of the type-material from Fulica atra L. from the Middle Ural, Russia, and new specimens from the same host species from Bulgaria. Since the type-series consists of specimens of two species, a syntype is designated as lectotype. The main differentiating characters of D. acuminata are the diorchoid rostellar hooks, 36-39 µm long, with a foliate epiphyseal thickening of the guard; cirrus-sac of variable length, usually reaching and often crossing the midline of proglottis, occasionally reaching antiporal osmoregulatory canals; evaginated cirrus with cylindrical basal part, bulbous middle part and pipette-like distal part; compact vitellarium situated dorsally to the ovary; copulatory part of vagina with muscular poral and middle portions and an antiporal sac-like reservoir; elongate eggs with polar filaments on their envelopes. The type-specimens of D. ransomi Johri, 1939 and D. longibursa Steelman, 1939 from Fulica americana Gmelin from USA are also re-examined and illustrated. Based on the present results, D. ransomi and D. longibursa are recognised as synonyms of D. acuminata. The previous records of the species are discussed. Diorchis acuminata is recognised as a specific parasite of Rallidae (mainly species of the genera Fulica and Gallinula) in the Holarctic.

Redescription and new records of Polymorphus trochus (Van Cleave, 1945)(Polymorphida: Polymorphidae), in Mexico.

Polymorphus trochus Van Cleave, 1945, is an acanthocephalan with limited distribution to the Americas and a common parasite of birds of the Rallidae family (Kinsella et al. 1973, McDonald 1988 and Amin 1992), mainly of the American coot Fulica americana Gmelin, 1789; however, despite existing records of this species, the knowledge and descriptions of its morphological characteristics are not sufficient. Therefore, the identification of this species can be confusing, particularly because it depends on the form of the proboscis of the female. Van Cleave (1945) provided a description and illustrations of this species based on 14 females and 2 males specimens collected in the intestine of F. americana from Lake Buckeye in Ohio, Lake Oneida in New York, and the Illinois River in Illinois; however, this description does not mention many traits that are taxonomically important. Years later, Nickol (1966, thesis not published) provided a description of P. trochus based on 36 mature specimens (14 females and 22 male) from Louisiana, but the author illustrated only the proboscis and included a schematic of the female. He described the shape and size of the proboscis in both sexes, provided measurements of the apical, middle and basal hooks of the proboscis armor, and measurements of the eggs. However, he did not mention the exact distribution of the hooks and spines of the trunk, the measurement of a complete row of hooks nor the shape of all the sexual organs, especially the female ones, which are important taxonomic characteristics in the polymorphids.

Review of five species of cyclocoelids (Digenea: Cyclocoelidae) from aquatic birds in Mexico with notes on their interspecific variation.

Based on a morphological approach, five species of cyclocoelids (Digenea: Cyclocoelidae) are revised based on material from birds in Mexico. The species studied are: Cyclocoelum cf. leidyi Harrah, 1922 from the black-necked stilt Himantopus mexicanus Müller (Recurvirostridae); Cyclocoelum mutabile (Zeder, 1800) from the northern jacana Jacana spinosa L. (Jacanidae) and the willet Tringa semipalmata Gmelin (Scolopacidae); Cyclocoelum pseudomicrostomum Harrah, 1922 from the American coot Fulica americana Gmelin (Rallidae); Selfcoelum lamothei Blend & Dronen, 2008, from the long-billed curlew Numenius americanus Bechstein (Scolopacidae); and Neohaematotrephus arayae Zamparo, Brooks, Causey & Rodriguez, 2003 from J. spinosa. New morphological data, illustrations and measurements are presented for these trematodes. Three species, insufficiently described, i.e. C. cf. leidyi, C. mutabile and C. pseudomicrostomum, are redescribed in detail. Our results indicate morphological variation in some important features used in the diagnosis of Cyclocoelum Brandes, 1892 (i.e. the presence or absence of oral sucker, the position of the genital pore relative to the pharynx, and the posterior extension of the uterus) and Selfcoelum Dronen, Gardner & Jiménez, 2006 (i.e. anterior extension of vitelline follicles). Finally, this study provides the first molecular data for the large subunit of the ribosomal RNA (28S rRNA) gene for N. arayae.

Metazoan Parasites of the American Coot,Fulica americana, from the Rio Grande Valley in Colorado and Southwest, Texas, U.S.A., with a Checklist of Parasites for North America and West Indies

A total of 100 American coots, Fulica americana Gmelin, 1789, were examined for metazoan parasites from the Chihuahua Desert, Middle Rio Grande Valley Texas, and from the Upper Rio Grande Valley, Colorado, U.S.A., between 1984 and 1986. There was no significant difference in helminth species richness or median abundance between the component communities from the 2 localities. Fifteen of the 25 helminth species collected were in common to both, and similarity was 65%. The same species in each of the 4 taxa, Notocotylus pacifera, Diorchis americana, Amidostomum fulicae, and Polymorphus spp., had the highest prevalence and abundance in both, and the same 5 species of acanthocephalans were also in common. Eight of the 9 species of ectoparasites were common, and similarity was 91%. In both host species, Pseudomenopon pilosum and Rallicola advenus were the most prevalent and abundant mallophagans, and Laemobothrian atrum was the least. The nasal mite Rallynyssus caudistigmus was present in hosts from both localities. Of the 3 unidentified species of feather mites, species 1 was the most prevalent and abundant in Texas and absent in hosts from Colorado, and species 3 was the most prevalent in hosts from Colorado. The following helminth species were present in all 3 seasonal samples in Texas: A. fulicae, D. americana, Diorchis ransomi, N. pacifera, Polymorphus trochus, and Tetrameres globosa, whereas D. americana had the highest mean intensity in all 3. Overall, 70 species of helminths (33 trematodes, 15 cestodes, 14 nematodes, and 8 acanthocephalans) have been recorded in F. americana from North America. All species, except Echinostoma americanum, have been reported from other species of hosts. The majority of species are generalists (90%), although the following are specialists and largely predictable in American coots: trematodes (N. pacifera and Cyclocoelum mutabile); cestodes (D. americana, and D. ransomi); nematodes (A. fulicae, in adult coots only); Pelecitus fulicaeatrae; and the acanthocephalan, P. trochus.

Resource partitioning among five species of waterfowl (Anasspp.) at an autumn migratory stopover: combining stable isotope and mercury biomarkers

The Saskatchewan River Delta (SRD) is North America’s largest inland delta and an important stopover site for waterfowl in the Central Flyway. However, little is known about their basic feeding ecology at this site and how species segregate or overlap in resource use. We used stable carbon (δ13C) and nitrogen (δ15N) isotopes and mercury concentrations ([Hg]) in liver tissue to trace use of local nutrient sources by five waterfowl species and tested for differences in diets among species, sexes, and age groups. Macrophytes were the dominant food source for Northern Pintail (Anas acuta L., 1758) and American Wigeon (Anas americana Gmelin, 1789) with median proportions of 0.86 and 0.98, respectively. There was also evidence of partitioning of resources, as Blue-winged Teal (Anas discors L., 1766) and Green-winged Teal (Anas carolinensis Gmelin, 1789) consumed invertebrates, as did a subset of Mallards (Anas platyrhynchos L., 1758), suggesting that these birds might minimize competition for resources during the short staging period in the SRD when waterfowl densities are high. Other isotopes or tracers, such as [Hg] that varied among sources (0.03–0.20 μg·g–1dry mass) and waterfowl species (0.22–3.19 μg·g–1dry mass), can be used for further refining dietary estimates.

Timing of nesting of upland-nesting ducks in the Canadian prairies and its relation to spring wetland conditions

Timing of breeding varies among waterfowl species and individuals, with strong effects on reproductive success, and may be related to habitat quality. Here, we analyse the start, span, and end of the nesting season for nine upland-nesting duck species at 166 Canadian Prairie–Parkland sites over 34 years to better characterize nesting patterns and test whether and how species respond to May pond abundances. Nesting metrics were compared between single-site versus multiple-site studies over 7 years to evaluate the effects of spatial scale and methodology. Strong, consistent differences in start of nesting were found among duck species, being earliest for Northern Pintail (Anas acuta L., 1758) and Mallard (Anas platyrhynchos L., 1758), followed by Northern Shoveler (Anas clypeata L., 1758), American Green-winged Teal (Anas crecca carolinensis Gmelin, 1789 = Anas carolinensis Gmelin, 1789), Blue-winged Teal (Anas discors L., 1766), American Wigeon (Anas americana Gmelin, 1789), Gadwall (Anas strepera L., 1758), and lastly by Lesser Scaup (Aythya affinis (Eyton, 1838)) and White-winged Scoter (Melanitta fusca deglandi (Bonaparte, 1850)). Span and end of nesting were related to May pond abundances, but the strength of these relationships varied among species, presumably reflecting the flexible (re-)nesting potential of individuals of some species in response to wetland-habitat quality.

First molecular identification of Australapatemon burti (Miller, 1923) (Trematoda: Digenea: Strigeidae) from an intermediate host Radix labiata (Rossmaessler) (Gastropoda: Lymnaeidae) in Europe.

The strigeid digenean species Australapatemon burti (Miller, 1923) (Trematoda: Digenea: Strigeidae) was originally described from North America, but recorded in the Neotropical region (Drago et al. 2007; Hernández-Mena et al. 2014; Blasco-Costa et al. 2016) and in Central Europe (Faltýnková et al. 2007). In Europe, this species is rare, and there is not much information about its range (Faltýnková et al. 2007; Soldánová et al. 2012). Australapatemon burti has a complex life cycle with three larval stages, two of which (sporocyst and cercaria) use several species of freshwater snails, and the third stage (metacercaria) use non-specific host hirudineans (Dubois 1968; Davies & Ostrowski de Núñez 2012; Blasco-Costa et al. 2016). Adult flukes are parasitic in the intenstines of various waterfowl species, such as ducks and swans (Drago et al. 2007; Hernández-Mena et al. 2014). Currently, the molecular data on this parasite species includes only nucleotide sequences of four adult specimens from Mexico (Hernández-Mena et al. 2014). Their hosts were Mexican duck, Anas diazi Ridgway, American Wigeon, Anas americana Gmelin, Cinnamon Teal, Anas cyanoptera Vieillot, and Ruddy Duck, Oxyura jamaicensis (Gmelin) (Anserformes: Anatidae).

Growth, survival and size-selective predation mortality of larval and juvenile inland silversides, Menidia beryllina (Pisces; Atherinidae)

A series of laboratory and field experiments were conducted to determine the relative importance of food limitation and predation as sources of mortality for Menidia beryllina (Cope) larvae and juveniles. Seven-day experiments using in situ mesocosms to exclude predators demonstrated significant growth (mean instantaneous growth rate of 0.122–0.135 day −1) and survival (mean 88–89%) for M. beryllina larvae in a Rhode Island, USA, estuary. These results suggest that food was not limiting for growth or survival and, therefore, that predation is likely the primary source of mortality for young-of-the-year (YOY) M. beryllina. Predation experiments were conducted in laboratory aquaria and in in situ mesocosms to assess the size-selectivity of potential predators. Laboratory-reared striped bass, Morone saxatilis Walbaum and field-collected white perch, Morone americana Gmelin, crevalle jack, Caranx hippos Linnaeus and bluefish, Pomatomus saltatrix Linnaeus, were presented with a choice of two or three size classes of laboratory-reared M. beryllina and allowed to feed for 3–24 h. For field-collected predators the experimental prey size range was similar to the size present in the field. Striped bass, white perch and crevalle jack selectively preyed on the smallest size classes. Bluefish, however, selectively preyed on the largest size class. These results suggest that size-specific survival of YOY M. beryllina may vary spatially and temporally depending on the particular suite of predators encountered by individual populations or cohorts. However, in the estuary studied predation mortality appears to be directed towards the larger members of the M. beryllina cohort.

CARIDEAN SHRIMPS ASSOCIATED WITH THE SLIMY SEA PLUME (PSEUDOPTEROGORGIA AMERICANA) IN MIDSUMMER AT GUANA ISLAND, BRITISH VIRGIN ISLANDS, WEST INDIES

ABSTRACT Fifty-one slimy sea plumes (Pseudopterogorgia americana Gmelin, 1791) were sampled for caridean shrimps at Guana Island, British Virgin Islands, during one week in July 1992. Sampling depth ranged from 3-22 m. Nine species were collected: Hippolyte nicholsoni Chace, 1972; Latreutes sp.; Neopontonides chacei Heard, 1986; Perclimenes cf. patae Heard and Spotte, 1991; Periclimenes cf. pauper Holthuis, 1951; Periclimenes sp.; Pseudocoutierea antillensis Chace, 1972; Tozeuma cf. cornutum Milne Edwards, 1881; and Trachycaris rugosa (Bate, 1888). A total of 1,418 specimens (including fragments) was obtained. The number of shrimp species per gorgonian ranged from 1-5; one gorgonian harbored 156 shrimps. The 2 predominant species, N. chacei and H. nicholsoni, occupy different mean depths (12.6 and 8.2 m, respectively). Sexual dimorphism assessed with Mann-Whitney U-tests was not apparent in the specimens of N. chacei (P > 0.05), but females of H. nicholsoni were significantly larger than males (P < 0.001). Minimum carapace length (CL, the tip of the rostrum to the posterior dorsal margin of the carapace) at which male N. chacei acquire a single appendix masculina spine is 1.25 mm; male H. nicholsoni can acquire a single spine at 0.9 mm CL. Histological sections of male N. chacei showed that shrimp with 0 or 1 spine are least likely to be mature. Female N. chacei can become ovigerous at 1.9 mm CL and female H. nicholsoni at 1.2 mm CL. The taxonomic status of 5 of the 9 species collected is uncertain.

Habitats and tidal accessibility of the marine foods of dabbling ducks and brant in Boundary Bay, British Columbia

The role of birds in intertidal food webs is mediated by effects of tides on the habitat, distribution, and accessibility of food organisms. We studied effects of elevation, sediment characteristics, vegetation, and tidal cycles on waterfowl feeding and food organisms in Boundary Bay, British Columbia, Canada from September to March 1990–1992. Percent dry mass of esophageal contents was mainly Zostera japonica leaves (84%) for American wigeon (Anas americana Gmelin), and leaves of Z. japonica (57%) and Z. marina (41%) for brant (Branta bernicla L.). Northern pintails (A. acuta L.) and mallards (A. platyrhynchos L.) ate mostly the leaves, seeds, and rhizomes of Z. japonica (48 and 72%, respectively) and gastropods (12 and 28%). Green-winged teal (A. crecca L.) ate mainly amphipods (68%) and saltmarsh seeds (19%). The well-sorted fine sand (median 0.125 mm) to medium sand (0.25 mm), and the low organic carbon content (1.31±0.12% dry mass), did not appear to vary sufficiently along 2.1- and 2.6-km transects to affect macroinvertebrate distributions. Three habitat zones were recognized: (1) upper intertidal (sandflats); (2) mid-intertidal (largely monotypic Z. japonica); and (3) lower intertidal (mixed Z. japonica and Z. marina). These zones, although related to elevation, had greater influence on amphipod distributions than did elevation alone or detrital biomass. Biomass and numbers of most invertebrate foods of waterfowl were greatest in the eelgrass zones, with the upper elevational limit of Z. japonica occurring at about Mean Water Level (MWL). Accordingly, wigeon, pintails, and mallards fed mostly below MWL. Because of seasonal tidal cycles, daily accessibility of areas below MWL but within reach of surfacefeeding waterfowl decreased from a mean of 10.8 h in October to 9.6 h in December. In October only 10 d and <12 h available feeding time, whereas in December and January every day had <12 h available feeding time. Seasonal effects of tides on accessibility might limit sufficient feeding by some waterfowl species in intertidal areas, increasing their reliance on alternative feeding sites.

Epibenthic gastropods of the middle Florida keys: the role of habitat and environmental stress on assemblage composition

A survey of epibenthic prosobranch gastropods was undertaken in both seagrass and hard substratum (coral or old reef rock) habitats on opposite sides of the Florida Keys (Florida Bay and Hawk Channel) to compare faunal differences attributable to differences in the above two habitats and environments. Additionally, two data sets (26 continuous months) of daytime dissolved oxygen, surface salinity and water temperature from Florida Bay (Long Key) and Hawk Channel (Key Largo) environments were compared to determine differences that might constitute environmental stresses likely to affect the fauna. The above data were collected to determine if several hypotheses concerning effects of stress on organisms, assemblage, community and faunal composition were consistent with data on assemblage structure. These hypotheses were that: (1) stress should reduce the average size of organisms; (2) shorten food chains; (3) reduce predation intensity; (4) reduce species richness and diversity; and (5) increase the relative abundance of predator-susceptible ancestral species (i.e. Archaegastropoda). Water quality data suggest that the two most likely forms of stress in deeper (>1 m) areas of Florida Bay adjacent to the Keys are cold water temperatures associated with winter cold fronts and low predawn oxygen associated with warm summer temperatures, high salinity, and periodic algal and seagrass drift buildups. Seagrass sites had high population densities and low diversity due to the dominance of Astraea americana Gmelin (American star shell) in Florida Bay and Modulus modulus L. in Hawk Channel seagrass habitats. Florida Bay sites had high species richness on a small spatial scale, but Hawk Channel sites had more species and greater encounter rates of new species on a larger scale. Predawn oxygen measurements taken during July in four habitats were positively correlated with prosobranch species richness and diversity. Faunal data, analysed on a population density basis, fit the above hypotheses of body size, trophic level, and evolutionary age of the species. Attempts to measure predation on an experimental prosobranch ( A. americana) were unsuccessful but a tethering experiment with a sea urchin ( Echinometra lucunter L.) indicated higher predation in the less stressful Hawk Channel than Florida Bay hard substratum sites. Stress appears to reduce the abundance of higher trophic levels (both prosobranch and finfish predators) resulting in the dominance of ancestral forms not adapted to predation but tolerant of environmental stress. Eutrophication or increased oxygen demands in Florida Bay could result in further species richness and diversity declines.

Vulnerability of striped bass Morone saxatilis Waldbaum eggs and larvae to predation by juvenile white perch Morone americana Gmelin

Striped bass Morone saxatilis Waldbaum early life stages and juvenile congeneric white perch M. americana Gmelin co-occur in Chesapeake Bay tributaries. Vulnerabilities of striped bass eggs and laboratory-reared larvae to predation by juvenile (58–65 mm total length) white perch were determined. Predation experiments of 15-min duration were carried out in 76-1 tanks with individual predators. Vulnerability of striped bass larvae was directly related to light level in the range 0–1000 lux, but turbidity level (0–15 NTU) had no effect on vulnerability. Eggs and larvae that were progeny of large or small female striped bass, and which differed in size-at-age, were found to be equally vulnerable to white perch predation. Predation rate on eggs was relatively low (1.7·15 min −1), increased on yolk-sac larvae (7.3·15 min −1) and was highest (13.1·15 min −1) on 12-day posthatch larvae, after which it declined. Larvae of 7.0–7.9 mm standard length and 0.25–0.49 mg dry wt were most vulnerable. Predation by white perch on striped bass eggs and larvae potentially is a significant cause of mortality in Chesapeake Bay tributaries, although additional laboratory and field experiments are needed to quantify its impact.

Cold-Hardiness in Pelecitus fulicaeatrae (Nematoda: Filarioidea), a Parasite of the Ankles of Fulica americana (Aves)

The filarioid nematode Pelecitus fulicaeatrae (Diesing, 1861) is considered cold-hardy. Adults and microfilariae became motile when placed in saline at 22 C after having been removed from thawed carcasses of their host, the American coot (Fulica americana Gmelin) (Aves: Gruiformes). Adult nematodes from 5 of 12 carcasses became active as did microfilariae from 4 of 5 carcasses. Carcasses had been frozen at an undetermined temperature below 0 C for an initial 14 days and then at -21 to -24 for 100-159 days.

Development of Skrjabinocerca prima (Nematoda: Acuarioidea) in Hyalella azteca (Amphipoda) and Recurvirostra americana (Aves: Charadriiformes), with comments on its precocity

Skrjabinocerca prima Shikhobalova, 1930 developed to the infective third stage in 40 days in Hyalella azteca (Saussure) maintained at 21 °C. Infective larvae occur free in the haemocoel and may impede the amphipod's motility because they lie semirigid and parallel to the longitudinal axis in the posterior abdominal segments. The genital primordium in infective-stage males was 200–520 μm long (averaging 19% of body length) and in females 860–1175 μm (averaging 42% of body length). This is unusually large, even compared with other acuarioids in which precocial development of the third-stage genital primordium is known. Additional evidence is provided for the hypothesis that precocity in nematodes is related to rapid maturity in the final host; in experimentally infected American Avocets (Recurvirostra americana Gmelin), moulting third-stage S. prima were found 2 days postinfection and moulting fourth stage at 4 days. Female nematodes contained embryonated eggs at 7 days; eggs in females became larvated between 10 and 18 days postinfection. In birds, the heads of larval and adult nematodes were attached to the mucosa of the buccal cavity or the upper third of the oesophagus, and adults provoked chronic inflammation in the form of yellow plaques. Worms are able to detach and reattach. Third-stage S. prima given to Marbled Godwits (Limosa fedoa (L.)) and Western Willets (Catoptrophorus semipalmatus inornatus (Brewster)) developed to maturity; the parasite has not been reported from the former species in the wild.

Development of Skrjabinoclava inornatae (Nematoda: Acuarioidea) in fiddler crabs (Uca spp.) (Crustacea) and Western Willets (Catoptrophorus semipalmatus inornatus) (Aves: Scolopacidae)

Skrjabinoclava inornatae Wong and Anderson, 1988 from the posterior half of the oesophagus and proventriculus of Western Willets (Catoptrophorus semipalmatus inornatus (Brewster)) developed to the infective third stage in fiddler crabs (Uca spp.) collected in Louisiana, U.S.A. This is the first report of the development of an acuarioid in a decapod. The third-stage larva was characterized by a dorsally bowed caudal end and one small dorsal protuberance and two large dorsally directed spines on the tail tip. The genital primordia were precociously developed in both male and female third-stage larvae. Larvae transferred experimentally to uninfected willets were found in the mucosa of the proventriculus and underwent the first moult less than 3 days and the fourth moult 5 days postinfection. Adult worms occurred mainly in the posterior end of the oesophagus and were mature 15 days postinfection. It is suggested that the rapidity of maturation of the worms in willets may be related to the precocious development of the genital primordia in the third-stage larvae. Marbled Godwits (Limosa fedoa L.) were infected experimentally. American Avocets (Recurvirostra americana Gmelin) and Black Terns (Chlidonias niger (L.)) given larvae did not become infected.

Mallophagan vectors and the avian filarioids: new subspecies of Pelecitus fulicaeatrae (Nematoda: Filarioidea) in sympatric North American hosts, with development, epizootiology, and pathogenesis of the parasite in Fulica americana (Aves)

Subspecies of Pelecitus fulicaeatrae (Diesing, 1861) Lopez-Néyra, 1956 are proposed for the first time. The parasite in the original type host, i.e., the Common Coot (Fulica atra L.) in Great Britain, becomes the nominotypical subspecies, namely Pelecitus fulicaeatrae fulicaeatrae (Diesing, 1861) n.subsp.; it requires further taxonomic study. Subspecies in two sympatric North American hosts are described, and transmission by lice (Mallophaga: Amblycera) is suggested to have played a role in their evolution. Pelecitus fulicaeatrae americanae n.subsp. in the American Coot (Fulica americana Gmelin) has narrower lateral alae at midbody in the male, tighter helical twisting and more rotations in the body of the adult female, and a vulva that tends to be closer to the end of the oesophagus than that of Pelecitus fulicaeatrae grisegenae n.subsp. in the Red-necked Grebe (Podiceps grisegena (Boddaert)). Development of P. f. americanae was followed in experimentally infected American Coots. At 20 days postinfection, worms had migrated to the definitive site in the ankles and developed to the adult stage; these worms were sexually immature and also differed in other morphologic ways from mature specimens. Worms at 210 and 265 d resembled those from wild-caught coots, and females contained microfilariae. Pelecitus f. americanae is reported for the first time in Wisconsin, North Dakota, and California and probably is widespread in coots in North America. Both nesting and wintering coots contained three age-classes of adult female worms (too young to produce microfilariae, producing microfilariae, senescent), suggesting that transmission is not restricted to any particular period during the year. In general, no evidence of infection was apparent upon external examination of intact wild-caught infected coots, whereas ankles of intact wild-caught infected grebes were frequently swollen. Upon internal examination of coots, a visible response to worms was also generally not observed. In a few coots, however, worms were within soft, thin-walled capsules and histologic examination revealed chronic proliferative tenosynovitis.

Some observations on Pseudomenopon pilosum (Amblycera: Menoponidae), the louse vector of Pelecitus fulicaeatrae (Nematoda: Filarioidea) of coots, Fulica americana (Aves: Gruiformes)

Breeding populations of Pseudomenopon pilosum (Scopoli, 1763) became established on 10 laboratory-reared juvenile American Coots (Fulica americana Gmelin) initially infested with 5 adult male and 5 adult female lice. Eggs of P. pilosum hatched less than 10 days after deposition and the combined duration of the three nymphal instars was 10–20 days. Nymphs and adults occupied all regions of the body. Pseudomenopon pilosum might thus acquire microfilariae of Pelecitus fulicaeatrae (Diesing, 1861) by simply randomly moving to and feeding on the legs where, in infected coots, the skin-inhabiting microfilariae of P. fulicaeatrae are known mainly to occur. Pseudomenopon pilosum occurred on all of 13 adult coots and three 1-week-old coot chicks collected in June in western Canada where P. fulicaeatrae is enzootic. Third-stage larvae of P. fulicaeatrae were found in adult P. pilosum on two of four adult coots harbouring microfilariae, but prevalence in lice was low (5.5% of 18 lice on one coot and 1.1% of 90 on the second) and only one third-stage larva was present in each infected louse. Four other species of lice were present on adult coots but only one other on 1-week-old chicks. Experiments showed that P. pilosum could occur as a straggler on chickens (Gallus gallus (L.)) and Red-necked Grebes (Podiceps grisegena (Boddaert)) although it did not establish on either species.

Redescription of Skrjabinocerca prima Shikhobalova, 1930 (Nematoda: Acuarioidea) from the American Avocet (Recurvirostra americana Gmelin)

Skrjabinocerca prima Shikhobalova, 1930 is redescribed from material collected from the American Avocet (Recurvirostra americana Gmelin) collected in Alberta, Canada (prevalence 88%). The parasite was not present in avocets collected from Manitoba.

Metazoan Parasites of Recurvirostra americana Gmelin (Aves), from Southwestern Texas and Monte Vista National Wildlife Refuge, Colorado, with a Checklist of Helminth Parasites Hosted by This Species in North America

Metazoan Parasites of Recurvirostra americana Gmelin (Aves), from Southwestern Texas and Monte Vista National Wildlife Refuge, Colorado, with a Checklist of Helminth Parasites Hosted by This Species in North America