Helminth biodiversity of Costa Rican Anurans (Amphibia: Anura)

One hundred and sixty-three frogs representing 21 species collected in Costa Rica were examined for helminths. Those found were: one species of Digenea (Mesocoelium monas), one species of Cestoda (Cylindrotaenia americana), 15 species of Nematoda, 11 species represented by gravid individuals (Aplectana hylambatis, Aplectana incerta, Aplectana itzocanensis, Capillaria recondita, Cosmocerca parva, Cosmocerca podicipinus, Falcaustra costaricae, Hedruris heyeri, Oswaldocruzia costaricensis, Oswaldocruzia nicaraguensis, Rhabdias savagei) and four species represented by larvae (Physaloptera sp., Porrocaecum sp., Spirocamallanus sp., Ascarididae gen. sp.) and three species of Acanthocephala, one species represented by gravid individuals (Anuracanthorhynchus lutzi) and two species by cystacanths (Centrorhynchidae gen. sp. and Oligacanthorhynchidae gen. sp.). Mean helminth diversity (number of helminth species) per frog species was 2.4 ± 0.3 SE, range: 1–6. Forty-nine new host records are reported. Costa Rican frogs are infected by generalist helminths, which infect other species of frogs from Central and South America.     

A new species of Melanagromyza (Diptera: Agromyzidae) mining leaves of Bromelia pinguin (Bromeliaceae) in a dry forest in Costa Rica

Melanagromyza rosales, sp. nov., from Costa Rica is described and its natural history is summarized. Larvae are miners in leaves of Bromelia pinguin, a large terrestrial rosette plant. They form conspicuous longitudinal mines that may be over 1 m long. Adult emergence is virtually simultaneous for all individuals, probably triggered by temperature cues. Populations are low for many generations with brief periods of abundance.     

Biting mechanism of the amphipod Anonyx (Crustacea: Amphipoda: Lysianassoidea)

Anonyx amphipods feed extensively on dead or weakened animals, often of large size. They cut off strips of food using the wide incisor processes of their mandibles like a pair of shears. The mandibles and associated mouthparts are specialized for this shearing action. The strips of food are coiled and packed into their proventriculi.     

Considerations about the genus Pentoniscus Richardson, 1913 (Crustacea: Isopoda: Oniscidea) with description of a new species

The status of the neotropical genus Pentoniscus Richardson, 1913 is reconsidered and a diagnosis of this genus is given. It is shown that Pentoniscus Richardson, 1913 is a valid genus and not a synonym of Philoscia Latreille, 1804 as discussed by Schultz (1968). The type species, Pentoniscus pruinosus Richardson, 1913 is redescribed and for the first time figured in detail. A new species of Pentoniscus Richardson, 1913 is described from Costa Rica, Central America, which differs remarkably from its congeners in being unpigmented and blind.     

Population study of the landhopper Talitroides topitotum (Crustacea: Amphipoda: Talitridae) in central Mexico

A population of Talitroides topitotum discovered in Mexico City in 1992, was studied during a one year cycle. Abundance varied significantly during the study period, high population numbers occurred from June to October with a marked decrease from November to May. Maximum total length was 12.5mm and the size at first reproduction for females was 4.0 mm total length. Talitroides topitotum reproduced all year, with a peak in June. A female biased sex ratio was obtained in every sample with a maximum of 4:1 in May. Fecundity varied from one to nine eggs per female and mean fecundity varied significantly through time. The results show that T. topitotum exhibits little variation among widely separated populations and, 4 years after introduction, a life cycle adjusted to the local weather.     

Notes on the occurrence of Talitrus dorrieni Hunt (Crustacea Amphipoda: Talitridae) in south-west England

Summary

The introduced amphipod crustacean Talitrus dorrieni is abundant in terrestrial localities on the Isles of Scilly, and has been found in three previously unrecorded localities in Cornwall. Although widespread on the islands, it is restricted to gardens and cultivated ground on the mainland. The origin of the colonies and the factors limiting their spread are discussed.     

New species of Monstrilloida (Crustacea: Copepoda) from the Eastern Tropical Pacific

Monstrilloid copepods were collected from the oceanic island Isla del Coco in the Eastern Tropical Pacific; two undescribed species were found, one of Cymbasoma and one of Monstrillopsis. The first species, represented by females only, is distinguished by the structure of its fifth legs, the antennular armature and the position of the ovigerous spines. The new Monstrillopsis, represented by male specimens, is distinguished by its genital lappets and details of the antennule armature. The isolation of this island, 532 km from the mainland, and the limited dispersal means of monstrilloids suggest potential endemism of these species. A recent record of Cymbasoma tumorifrons from the Mexican Pacific was found to represent a new species of Cymbasoma. It can be distinguished from C. tumorifrons, probably a Mediterranean form, by its body shape and antennular armature. These findings double the number of monstrilloid species known from the Eastern Tropical Pacific.     

Apodidymochelia,a new genus of gammaridean amphipod from the tropical Atlantic Ocean (Crustacea: Amphipoda: Didymochellidae)

Apodidymochelia castellata, new genus, new species is the second genus and fourth species in the rare and poorly known family Didymocheliidae. Apodidymochelia is separated from Didymochelia primarily on mandible structure. This record extends the known range of the family into the Atlantic Ocean.     

Aspects of the life history and reproductive biology of the introduced terrestrial amphipod Arcitalitrus dorrieni (Hunt) at two sites in Co. Galway,Ireland

The reproductive biology of Arcitalitrus dorrieni (Hunt) was investigated over a period of 25 months at a deciduous and a coniferous forest site at Kylemore, Co. Galway, Ireland. The species has an annual, univoltine reproductive cycle with ovigerous females found throughout the year. Recruitment of juveniles begins in May–June with a peak of reproductive activity in August–September. The populations at each site show a bimodal size-distribution for most of the year, with a unimodal distribution in March, April and May. Mortality occurs exponentially, and the life-span is 20–22 months. Mean fecundity was 5·65 eggs per female and was dependent on female size, egg size and brood stage. Brood mortality was 37·5% at Addergoole and 29·8% at Tullywee Bridge.     

The epibionts of beach hoppers (Crustacea: Talitridae) of the North American Pacific coast

The beach hoppers Megalorchestia californiana and M. corniculata (Crustacea: Talitridae) were studied for the interaction of two of their epibionts. Rhabditid nematodes reside under the host's dorsal pereonites where they may be facultative parasites or feed on bacteria and detritus associated with the host. The mite Thinoseius brevisternalis (Canaris, 1962) (Acari: Eviphididae) preys upon the above nematodes. Both nematodes and mites also use the host as transport between patches of beach wrack. Other epibiotic Acari on talitrids are also reported here.     

Association of a juvenile phoretic uropodid mite with the beach hopper Traskorchestia traskiana (Stimpson, 1857) (Crustacea: Talitridae)

A phoretic association of an undescribed uropodid deutonymph (Acari: Uropodidae) with the beach hopper Traskorchestia traskiana (Crustacea: Talitridae) is examined. Only juvenile mites (deutonymphs) were found attached to the coxal gills of the 257 beach hoppers examined. Both prevalence (range = 27·1–75·0%) and mean intensity (range = 1·3–3·7) increased as host size increased, possibly due to increased exposure time to the mites and a greater area for attachment in larger hosts. Among the gills, the mites exhibited a preference for coxal gill 5, which may be due to pH and humidity gradients but did not seem to be influenced by grooming or agitation of the gills by adjacent appendages.     

Ultrastructure of the pereopodal dactyls in the family Phronimidae Dana, 1852 (Crustacea: Amphipoda: Hyperiidea)

Species of the Phronimidae were studied for the micromorphology of their pereopods. Novel structures were found on the dactyls and are described in detail. A hypothesis is advanced that these structures serve also for external digestion and absorption of the tissues of their gelatinous plankton hosts.     

A phylogenetic analysis of the Eriopisa complex (Crustacea: Amphipoda: Melitidae) and a new species from beach interstitia in Venezuela

The taxonomy and phylogeny of the Eriopisa complex (Amphipoda: Melitidae) has proven to be highly controversial (Stock, 1980; Karaman, 1984; Stock and Sanchez, 1987). A new species of Eriopisa from beach interstitia in Venezuela leads us to reconsider a revision of the Eriopisa complex. We present a phylogenetic analysis based on morphology and comment on the issues of morphological continuity among genera of the Eriopisa complex.     

A new species of Valettia (Crustacea: Amphipoda) and the relationship of the Valettidae to the Lysianassoidea

The family Vallettidae is re-established to accommodate Valettia coheres Stebbing, 1888 and V. hystrix sp. nov. Although closer to the Lysianassoidea than to any other gammaridean superfamily, characters of the mandible, maxillae, gnathopods and oostegites preclude membership of that superfamily. Further assessments of the Valettidae and other family groups peripheral to the Lysianassoidea will be required before formal high-level classification can be established.     

On the status of Arcitalitrus dorrieni (Crustacea: Amphipoda) on the island of Colonsay,Inner Hebrides

The presence of the landhopper Arcitalitrus dorrieni (Hunt) is reported on the island of Colonsay, Inner Hebrides. It is widely distributed there amongst deciduous leaf litter in forested areas but also occurs in bracken litter and scrub grassland. The species is an introduction from Australia, doubtless transported inadvertently among plants brought to the gardens at Colonsay House. It is, however, not restricted to the ornamental plantings but has colonized native woodland. Maximum population density recorded under leaf litter was 680 m². Amphipods avoid waterlogged or dry situations preferring to burrow in moist soil under litter from deciduous trees. Coniferous woodlands are more sparsely colonized. Rate of spread (minimum) from the original locus is calculated at c. 25 m/year. Arcitalitrus may prefer to eat sycamore leaves (cf. oak, beech). Ovigerous females are reported for May but no evidence exists for a release of young any earlier in the year. Immature amphipods seem to live more covert lives in the soil beneath the superficial litter layer. Eggs are relatively large and few in number. Amphipods may avoid ants but may have a mite living in phoretic or ectoparasitic association.     

Natural history of the lizard Enyalius perditus (Squamata: Leiosauridae) from an Atlantic forest remnant in southeastern Brazil

The natural history of the lizard Enyalius perditus was studied from August 2005 to July 2006, at Parque Estadual Nova Baden, in the municipality of Lambari, State of Minas Gerais, south-eastern Brazil. We found that E. perditus may be considered a semi-arboreal species, like other species in the genus, sleeping on vegetation (slim branches or large leaves) at night, possibly to minimize predation. Females with enlarged follicles or oviducal eggs were found from November to January and juveniles recruited at the end of the dry season and beginning of the rainy season, in October. The diet of this lizard is composed mainly of Lepidoptera larvae, Araneae and Formicidae. Females were larger than males, and juvenile coloration is similar to that of adult females.     

The occurrence of the genus Ingolfiella (Crustacea,Amphipoda) in South Africa,with description of a new species

Abstract

The occurrence in South West Africa, i.e. within the confines of the Republic of South Africa, of the Amphipod genus Ingolfiella Hansen is recorded. The species is subterranean, is larger than any of the previously known species, and is described as I. opisthodorus sp. n. It is compared with I. leleupi Ruffo from the Congo and Northern Rhodesia. The majority of the specimens seem to be females although none has even a trace of oostegites or brood lamellæ. They exhibit a marked dimorphism of the first pair of pleopods, chiefly in specimens exceeding 14 mm. in body length; a juvenile form of this pair occurs in specimens measuring 12 to 14 mm. A few supposed males, among the last specimens to be collected (in June), are smaller than the supposed females but the two pairs of gnathopods are relatively larger and of a different form.     

A new deep-sea Psammogammarus species (Crustacea: Amphipoda: Eriopisidae) from the continental slope of the SE Gulf of Mexico

A new deep-sea species of amphipod collected at a depth of 1317 m from the soft bottom of the Bay of Campeche, SW Gulf of Mexico, is herein described. The sediment included a high proportion of silt and organic carbon. The specimen examined in this study was collected during the Oceanographic Expedition Xcambó-4, along the Bay of Campeche, aboard the RV Justo Sierra. The new species represents the sixteenth known species of the genus Psammogammarus worldwide. This new species is the second Psammogammarus recorded from the deep sea, and the first record of the genus for the Gulf of Mexico. Identification keys to males and females of Psammogammarus species are provided. Psammogammarus barrerai sp. nov. is characterised by head with anteroventral notch present; gnathopods 1 and 2 palmar margins oblique, and basis of pereopod 7 forming a wide serrated posterior lobe.

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