Trypanosoma cruzi I genotypes in different geographical regions and transmission cycles based on a microsatellite motif of the intergenic spacer of spliced-leader genes

The intergenic region of spliced-leader (SL-IR) genes from 105 Trypanosoma cruzi I (Tc I) infected biological samples, culture isolates and stocks from 11 endemic countries, from Argentina to the USA were characterised, allowing identification of 76 genotypes with 54 polymorphic sites from 123 aligned sequences. On the basis of the microsatellite motif proposed by Herrera et al. (2007) to define four haplotypes in Colombia, we could classify these genotypes into four distinct Tc I SL-IR groups, three corresponding to the former haplotypes Ia (11 genotypes), Ib (11 genotypes) and Id (35 genotypes); and one novel group, Ie (19 genotypes). Genotypes harbouring the Tc Ic motif were not detected in our study. Tc Ia was associated with domestic cycles in southern and northern South America and sylvatic cycles in Central and North America. Tc Ib was found in all transmission cycles from Colombia. Tc Id was identified in all transmission cycles from Argentina and Colombia, including Chagas cardiomyopathy patients, sylvatic Brazilian samples and human cases from French Guiana, Panama and Venezuela. Tc Ie gathered five samples from domestic Triatoma infestans from northern Argentina, nine samples from wild Mepraia spinolai and Mepraia gajardoi and two chagasic patients from Chile and one from a Bolivian patient with chagasic reactivation. Mixed infections by Tc Ia + Tc Id, Tc Ia + Tc Ie and Tc Id + Tc Ie were detected in vector faeces and isolates from human and vector samples. In addition, Tc Ia and Tc Id were identified in different tissues from a heart transplanted Chagas cardiomyopathy patient with reactivation, denoting histotropism. Trypanosoma cruzi I SL-IR genotypes from parasites infecting Triatoma gerstaeckeri and Didelphis virginiana from USA, T. infestans from Paraguay, Rhodnius nasutus and Rhodnius neglectus from Brazil and M. spinolai and M. gajardoi from Chile are to our knowledge described for the first time.     

Analysis of the potential geographic range of the Pacific oyster <Emphasis Type="Italic">Crassostrea gigas</Emphasis> (Thunberg, 1793) based on surface seawater temperature satellite data and climate charts: the coast of South America as a study case

Ecological niche modeling based on surface seawater (SST) and atmospheric (AT) temperature records was used to predict the potential range of distribution of Crassostrea gigas, focusing on the South American coast as a study case. In its native range, the species maintains self-sustaining populations at thermal regimes with mean SST ranging from 14.0° to 28.9°C for the warmest month and from −1.9° to 19.8°C for the coldest month of the year. Settlement is also constrained to mean AT varying between 15° and 31°C for the warmest month and between −23° and 14°C for the coldest month of the year. Latitudinal limits for the species’ distribution in South America predicted by the analysis of AT regimes were Valdivia-Chiloe Island (39.8o–42.0°S, Chile) and Pisco (13.4°S, Peru) on the Pacific coast, and San Julian port (49.3°S) (Argentina) and Garopaba-Rio Grande (28.0°–32.0°S, Brazil) on the Atlantic coast. Geographical limits of distribution predicted by analysis of SST regimes were Chiloe Island (42.0°S, Chile) and Mancora (4.1°S, Peru) on the Pacific coast, and Puerto Deseado ria (47.7°S, Argentina) and Paranaguá (25.7°S, Brazil) on the Atlantic coast. Therefore, SST regimes would expand the potential range on the Pacific coast equatorward relative to AT.     

Reconstruction of the biogeographical history of Malesherbiaceae

Malesherbiaceae are xerophytic plants of Chile, Peru, and Argentina. The 24 species of the only genus,Malesherbia, live in a variety of arid habitats in the Pacific coastal desert and adjacent Andes of Peru, Chile, and neighboring Argentina. Taxa with distributions in both Peru and Chile are rare; for this reason the family provides an excellent case study for the biogeography of this region of western South America. Phylogenetic analysis of ITS sequence data using Turneraceae as an outgroup shows a correlation between the phylogeny and the distribution of Malesherbiaceae. The origin of the family is placed in the late Miocene to early Pliocene, when the region became permanently arid. The five major clades of the family likely diverged during the Pliocene. A single clade consisting of species native to Peru and the Atacama Desert indicates that the family was introduced to Peru once. Most modern species appear to have evolved in response to Pleistocene climatic fluctuations.

---

Resumen  Las Malesherbiaceae son plantas xerófitas de Chile, el Perú, y Argentina. Las 24 especies del genero único,Malesherbia, viven en una variedad de hábitats en el desierto costero del Pacífico y en la zona andina vecina en el Perú, Chile, y Argentina. Los taxones con distribuciones tanto en el Perú como en Chile son raros; por eso la familia es un buen ejemplo para el estudio de la biogeografía de esta región del oeste de América del Sur. El análisis filogenético de datos de secuencias de ITS usando Turneraceae como un grupo extemo muestra una correlación entre la filogenia y la distribución de Malesherbiaceae. La familia se originó en el Mioceno tardío o Plioceno temprano, cuando la región se volvió permanentemente árida. Los cinco clados mayores de la familia probablemente divergieron en el Plioceno. Un solo clado que tiene especies nativas a Perú y el Desierto de Atacama indica que la familia llegó al Perú una vez. La mayoría de las especies modernas probablemente evolucionaron en respuesta a las fluctuaciones climáticas en el Pleistoceno.

     

Genetic and morphological differentiation of Porphyra and Pyropia species (Bangiales,Rhodophyta) coexisting in a rocky intertidal in Central Chile

A recent molecular taxonomic study along the Chilean coast (18° S–53° S) described 18 candidate species of bladed Bangiales of which only two were formally described. Few studies focused on local genetic and morphological diversity of bladed Bangiales and attempted to determine their intertidal distribution in contrasting habitats, and none were performed in Chile. To delimit intertidal distributions of genetic species, 66 samples of bladed Bangiales were collected at Maitencillo (32° S) in four zones: a rocky platform, a rocky wall, and two boulders zones surrounded by sandy and rocky bottoms, respectively. These samples were identified based on sequences of the mitochondrial COI and chloroplast rbcL markers. We also collected 87 specimens for morphological characterization of the most common species, rapidly assessing their putative species identity using newly developed species‐diagnostic (PCR‐RFLP) markers. Eight microscopic and two macroscopic morphological traits were measured. We described and named three of four species that predominate in Maitencillo (including Pyropia orbicularis): Pyropia variabilis Zapata, Meynard, Ramírez, Contreras‐Porcia, sp. nov., Porphyra luchea Meynard, Ramírez, Contreras‐Porcia sp. nov., and Porphyra longissima Meynard, Ramírez, Contreras‐Porcia, sp. nov. With the exception of Po. longissima restricted to boulders surrounded by sandy bottom, and a morphotype of Py. variabilis restricted to rocky walls, the other species/morphotypes have overlapping intertidal distributions. Except for Po. longissima, which is clearly differentiated morphologically (longest and thinnest blades), we conclude that morphology is not sufficient to differentiate bladed Bangiales. Our findings underscore the importance of refining our knowledge of intrinsic and environmental determinants on the distribution of bladed Bangiales.     

Is Anisakis simplex s.l. a biological marker for stock identification of Strangomera bentincki from Chile?

The absence of the larval Anisakis simplex s. l. in samples from central Chile but heavy infections in fish from southern localities suggest the existence of two stocks of Strangomera bentincki, one closely associated with the central coast of Chile (landing port San Antonio and Talcahuano, c. 33° 30′ S–36° 40′ S) and the other associated with southern Chile (landing port Puerto Montt, c. 41° 30′ S). Results confirm the usefulness of metazoan parasites, like A. simplex s. l. as biological markers.     

Heteropyknotic filament in spermatids of Triatoma melanocephala and T. vitticeps (Hemiptera,Triatominae)

The species Triatoma melanocephala and T. vitticeps are vectors of Chagas disease in Brazil. An analysis of the number of chromosomes has led to the proposal of the exclusion of both these species and T. tibiamaculata from the Brasiliensis subcomplex because of their similarities to the triatomines of North America. T. melanocephala has been found to have morphologic characteristics that are very similar to those of T. vitticeps, and these species have been considered synonymous. Thus, this paper analyzes the spermiogenesis of T. melanocephala and T. vitticeps in order to compare the two and to evaluate another possible relationship between the species. This study describes spermatogenesis and observes the morphology, cell size, and cytogenetic characteristics of triatomines. In all T. melanocephala cells, a slightly prominent peripheral heteropyknotic filament was observed. In T. vitticeps, an extensive peripheral heteropyknotic filament was observed in spermatids. This filament was observed in either the periphery or the middle of the cell. Thus, this paper describes the spermiogenesis stage of two cryptic species of triatomines and suggests that the central heteropyknotic filament can be used as a tool in the diagnosis of T. vitticeps as a vector of Chagas disease.     

Characterisation of Trypanosoma cruzi populations by dna polymorphism of the cruzipain gene detected by single-stranded dna conformation polymorphism (SSCP) and direct sequencing

Fifty fresh isolates of Trypanosoma cruzi from Triatoma dimidiata vectors and 31 from patients with Chagas disease were analysed for DNA polymorphisms within the 432-bp core region of the cruzipain gene which encodes the active site of cathepsin L-like cystein proteinase. The cruzipain gene showed signs of polymorphism consisting of four different DNA sequences in Central and South American isolates of T. cruzi. The PCR fragments of Guatemalan isolates could be divided into three groups, Groups 1, 2 and 3, based on different patterns of single-stranded DNA conformation polymorphism. All of the strains isolated from Brazil, Chile, and Paraguay, except for the CL strain, showed a Group 4 pattern. Two to four isolates from each group were analysed by cloning and sequencing. A silent mutation occurred between Groups 1 and 2, and five nucleotides and two aa substitutions were detected between Groups 1 and 3. The DNA sequence of Group 4 contained five nucleotides and one aa substitution from Group 1. All of the DNA sequences corresponded well with the single-stranded DNA conformation polymorphism. The Group 1 isolates, the majority in the Guatemalan population (70/81, 86.4%), were isolated from both triatomines and humans, but Group 3 were isolated only from humans. Moreover, the Group 2 isolates were detected only in triatomine vectors (9/50; 18%), but never in humans (0/32, P<0.05) suggesting that this group has an independent life-cycle in sylvatic animals and is maintained by reservoir hosts other than humans.     

On some ecological aspects of the lugworm <Emphasis Type="Italic">Abarenicola affinis chiliensis</Emphasis> Wells, 1963 (Polychaeta: Scolecida: Arenicolidae) from shallow soft bottoms of northern Chile

We conducted an ecological study of a population of the polychaete Abarenicola affinis chiliensis in the shallow subtidal zone of Caleta Guardiamarina Riquelme in northern Chile. The study area is characterized by a hypoxic bottom consisting of fine sands and a silt-clay mixture, with high values of total organic matter content (TOM > 20%). During the two study periods (spring 1996 and 1997), the numerical contribution of A. affinis chiliensis to the total macrofauna was greater than 80%. A similar pattern was recorded for biomass, with A. affinis chiliensis surpassing 95% of the total macrofauna biomass. Statistical analyses did not detect significant differences in environmental and biotic variables between years (with the exception of salinity, which increased slightly), indicating temporal stability of these variables over the study period. Our results do not support the hypothesis of Wells that seawater temperatures act as a physical barrier impeding the dispersal of Abarenicola species. This hypothesis should be reexamined for some representatives of Abarenicola on the Pacific coast of South America.     

Ecoepidemiology,short history and control of Chagas disease in the endemic countries and the new challenge for non-endemic countries

Chagas disease is maintained in nature through the interchange of three cycles: the wild, peridomestic and domestic cycles. The wild cycle, which is enzootic, has existed for millions of years maintained between triatomines and wild mammals. Human infection was only detected in mummies from 4,000-9,000 years ago, before the discovery of the disease by Carlos Chagas in 1909. With the beginning of deforestation in the Americas, two-three centuries ago for the expansion of agriculture and livestock rearing, wild mammals, which had been the food source for triatomines, were removed and new food sources started to appear in peridomestic areas: chicken coops, corrals and pigsties. Some accidental human cases could also have occurred prior to the triatomines in peridomestic areas. Thus, triatomines progressively penetrated households and formed the domestic cycle of Chagas disease. A new epidemiological, economic and social problem has been created through the globalisation of Chagas disease, due to legal and illegal migration of individuals infected by Trypanosoma cruzi or presenting Chagas disease in its varied clinical forms, from endemic countries in Latin America to non-endemic countries in North America, Europe, Asia and Oceania, particularly to the United States of America and Spain. The main objective of the present paper was to present a general view of the interchanges between the wild, peridomestic and domestic cycles of the disease, the development of T. cruzi among triatomine, their domiciliation and control initiatives, the characteristics of the disease in countries in the Americas and the problem of migration to non-endemic countries.     

Invasion of rural houses by wild Triatominae in the arid Chaco

Triatomines are the vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease, the main endemic disease affecting five to seven million people in Latin America. Besides Triatoma infestans, the most important T. cruzi vector in the Gran Chaco region, other triatomine species associated with sylvatic birds and mammals are responsible for the maintenance of the wild cycle of T. cruzi. The present study aimed at evaluating the house invasion by sylvatic triatomine species in rural communities of the Los Llanos region (La Rioja, Argentina) and its association with environmental variables. House invasion by flying adult triatomines was recorded by trained collectors that surveyed over 377 houses distributed over 73 localities in a 56,600 km² study region, between October, 2014 and February, 2015. The result of the study showed the frequent house invasion by adult triatomines: 26.3% houses were infested in 53% of the localities. Seven sylvatic triatomine species were collected, with T. guasayana and T. garciabesi among the most abundant. House invasion by triatomine species showed no spatial aggregation and was not associated with temperature, precipitation, or vegetation cover at the spatial scale considered in the present study. House invasion by the epidemiologically important T. infestans is a concern of rural communities. Besides constituting a latent, although low, risk, the presence of these species negatively interferes with the vigilance activities of the provincial Chagas disease program.     

Peridomiciliary colonies of Triatoma vitticeps (Stal, 1859) (Hemiptera, Reduviidae, Triatominae) infected with Trypanosoma cruzi in rural areas of the state of Espírito Santo, Brazil

In Brazil, the colonization of human dwellings by triatomines occurs in areas with native vegetation of the caatinga or cerrado types. In areas of Atlantic forest such as in the Brazilian state of Espírito Santo, there are no species adapted to live in human habitations. The few autochthonous cases of Chagas disease encountered in Espírito Santo have been attributed to adult specimens of Triatoma vitticeps that invade houses from forest remnants. In recent years, the entomology unit of the Espírito Santo State Health Secretariat has recorded nymphs infected with flagellates similar to Trypanosoma cruzi in rural localities. Entomological surveys were carried out in the residences and outbuildings in which the insects were found, and serological examinations for Chagas disease performed on the inhabitants. Four colonies were found, all associated with nests of opossums (Didelphis aurita), 111 specimens of T. vitticeps, and 159 eggs being collected. All the triatomines presented flagellates in their frass. Mice inoculated with the faeces presented trypomastigotes in the circulating blood and groups of amastigotes in the cardiac muscle fibres. Serological tests performed on the inhabitants were negative for T. cruzi. Even with the intense devastation of the forest in Espírito Santo, there are no indications of change in the sylvatic habits of T. vitticeps. Colonies of this insect associated with opossum nests would indicate an expansion of the sylvatic environment into the peridomicile.     

Population structure in Chilean hake Merluccius gayi as revealed by mitochondrial DNA sequences

Genetic variation and divergence among samples of Chilean hake Merluccius gayi, from three localities off the coast of Chile and one locality off the coast of northern Peru, were assessed using sequences from the control region of mitochondrial DNA. Homogeneity tests revealed occurrence of at least three distinct genetic stocks of M. gayi within the region sampled. Factors potentially contributing to genetic divergence among M. gayi probably include hydrodynamics and behaviour.     

Infestation of arboreal nests of coatis by triatomine species,vectors of Trypanosoma cruzi,in a large Neotropical wetland

The coati (Nasua nasua, Carnivora) is a medium‐sized mammal common in the Pantanal of Brazil. Unlike most mammals, coatis construct arboreal nests used for resting and reproduction. In this region, the coati is an important host of Trypanosoma cruzi, the causative agent of Chagas disease. There are two possible routes through coatis can be infected by T. cruzi: the oral route or the vectorial route. However, the relative importance of each of these routes in the infection of coatis and its role in the sylvatic cycle of the parasite are unknown. Our objectives were to investigate: (i) whether coati nests were infested by triatomine bugs, (ii) what species were frequent in the nests, (iii) whether the triatomines in nests were infected by T. cruzi, and (iv) what were the food resources of these triatomines. Eight of the 24 nests sampled were infested with triatomines, a total of 37 specimens of at least two species (Rhodnius stali and Triatoma sordida). In one nest, R. stali and T. sordida co‐occurred and both fed on multiple resources, including coatis. This is the first report of triatomines occurring in arboreal nests of coatis. The co‐occurrence of two different genera of triatomine vectors and coatis within the limited space of the coati nests provide multiple opportunities for the exchange of the protozoan parasite through both the vectorial and oral transmission routes.     

Phylogeny, morphology, and biogeography ofChuquiraga, an Andean-Patagonian genus of Asteraceae-Barnadesioideae

Chuquiraga is a genus of 23 species of evergreen shrubs endemic to South America. It is distributed principally along the Andes from Colombia to Chile and Argentina, and it is especially diversified in the Central Andes and in the deserts and semideserts of southern South America. The genus exhibits a wide array of leaf-morphology types and two different head and floral types apparently related to hummingbird and insect pollination. In this study, phylogenetic relationships amongChuquiraga species were resolved by parsimony cladistic analysis using morphological characters. The resulting cladogram was used to interpret morphological, ecological, and biogeographical patterns in a historical context. Biotic and abiotic environmental factors hypothesized to have exerted selective pressure on morphological traits of its species were optimized onto the phylogeny to suggest how and when these factors may have affected the evolution and diversification of the genus. Results suggest an origin of the genus in southern South America, with two major evolutionary radiations, one more northern in the Central and Northern Andes, and the other in the Southern Andes and the North Chilean, Patagonia and Monte Deserts. Pollination by hummingbirds seems to have been an important factor in the origin of the northern clade, affecting floral morphology. Herbivory by vertebrates and increased aridity seem to have been important selective forces in the evolution and diversification of the southern clade, especially affecting leaf morphology. These changes were probably associated with the major elevation of the Andes in late Tertiary and with the hyperaridization and climatic fluctuations of Pleistocene and Holocene times.

---

Resumen   Chuquiraga es un género con 23 especies de arbustos perennifolios endémico de América del Sur. Se distribuye principalmente a lo largo de los Andes desde Colombia hasta Chile y Argentina y está especialmente diversificado en los desiertos y semidesiertos de América del Sur. El género presenta un amplio espectro de tipos de morfología foliar y dos tipos florales y de capítulos aparentemente relacionados con la polinización por colibríes y por insectos. En este trabajo las relaciones filogenéticas entre las especies deChuquiraga se resolvieron mediante análisis cladístico de parsimonia utilizando caracteres morfológicos. El cladograma resultante se empleó para interpretar patrones morfológicos, ecológicos y biogeográficos de las especies en un contexto histórico. Factures bióticos y abióticos que se han hipotetizado que han ejercido presión selectiva sobre los caracteres morfológicos fueron optimizados sobre la filogenia para sugerir cómo y cuándo podrían haber afectado la evolución y la diversificación del género. Los resultados obtenidos sugieren un origen del género en el sur de América del Sur, y dos principales radiaciones evolutivas, una más al norte en los Andes Centrales y en los Andes del Norte, y la otra más al sur en los Andes del Sur y en los desiertos del norte de Chile, la Patagonia y el Monte. La polinización por colibríes parece haber sido un factor importante en el origen del clado del norte, afectando la morfología floral. La herbivoría por vertebrados y el incremento en la aridez parecen haber sido fuerzas selectivas importantes en la evolución y diversificación del clado austral, afectando especialmente la morfología foliar. Estos cambios probablemente estuvieron asociados a la elevación máxima de los Andes a fines del Terciario y a la hiperaridización y fiuctuaciones climáticas del Pleistoceno y Holoceno.

     

Records of the land planarian Polycladus gayi (Tricladida,Geoplanidae) preying on black snails Macrocyclis peruvianus (Gastropoda,Macrocyclidae)

Polycladus gayi is a colourful and easily recognizable land planarian native to the temperate to cold rainforests of the west coast of southern South America, in Chile and Argentina; however, its ecology is poorly understood. Here, we describe the first records of P. gayi preying on a black snail Macrocyclis peruvianus in the wild. Two events were recorded, the first in a healthy forest in Llancahue Alto, Panguipulli, Chile, during the austral summer of 2023, and the second in a mature evergreen forest in the coastal range of La Union, Chile. These records expand our knowledge of the feeding habits and behaviour of P. gayi and add M. peruvianus to its prey list.     

A new stem-group chordate (Cornuta) from the Llandeilo of Czechoslovakia and the cornutemitrate transition

A new stem chordate, Prokopiytis mergli, from the Middle Ordovician (Llandeilo) of Bohemia, Czechoslovakia is reconstructed and described. It proves to be the most crownward cornute yet known, sharing with the mitrates (primitive crown chordates) a number of derived features unknown in other cornutes. Such features include: the position of the gonopore-anus, the absence of major dorsal plates from the fore tail and the expansion of the marginal plates of the head onto the dorsal surface. Some other characteristics of P. mergli are a fore tail composed of only three segments and an elongate head. Only three hind-tail ossicles are known. The elongate head and small number of fore-tail segments are autapomorphies of P. mergli. The locomotory cycle is reconstructed and it is concluded that P. mergli moved rearwards, pulled largely by its mid and hind tail. The calcichordate theory is defended and the orientation of the mitrates considered. P. mergli reinforces the view that the convex surface of the mitrates was ventral in life. The origin of the atrial chambers of mitrates is discussed and a new homology proposed between the anterior ventral fore-tail plates of cornutes and what were formerly called plates g and j of mitrates. Nový chordát z kmenové skupiny/stem-group/Cornuta zeského Ilandeila, pechod mezi skupinami Cornuta a Mitrata. V práci je popsán a rekonstruován nový zástupce kmene chordátu Prokopicystis mergli gen. et sp. n., z eského llandeila/eskoslovensko/. Jde o dosud známého nejvýe organizovaného kornuta, vykazukícíhoadu znaku shodných s chordáty mitrátníimi a zcela neznámýc u ostatních pedstavitelå skupiny Cornuta. Tyto znaky zahrnují: pozici gonopor-análníiho otvoru, nepítomnost hlavních dorzálních desek v proximálníásti ocasu a expanzi marginálníc desek hlav na dorzální stranu. K dalím charakteristickým znakåum druhu P. mergli patí protáhlá hlava a proximálníást ocasu tvoená jen temi segmenty. V distálníásti ocasu jsou rovn známy jen 3 destiky. Protáhá halva a maly pocet segmentåu proximálníásti ocasu jsou u. P. mergli autapomorfiemi. V práci je také rekonstruován pohybový cyklus ivoicha se závrem, e P. mergli se pohyboval dozadu, pozvolným tahem stední a zadníáSTI OCASU> Je zde hájena tzv. kalcichordátová teorie a diskutována orientace mitrátåu. VyAsledky studia podporují domnnku, e skupiny Mitrata byla za ivota konvexní strana jejich theky stranou ventrální. Je diskutován påuvod atriálnich koma?rek skupiny Mitrata. Souasn jsou pova ovány pední ventrálni desek pedníásti za homologicke s desek díve oznaovanými jako g a j u mitr     

Biogeographical patterns in endoparasite communities of a marine fish (Sebastes capensis Gmelin) with extended range in the Southern Hemisphere

Aim The endoparasites of Sebastes capensis Gmelin are examined over most of its geographical range (coasts of Peru, Chile, Argentina and South Africa) to determine: (1) whether the endoparasite communities of this fish show zoogeographical patterns; and (2) if so, whether there are any relationships between spatial variations in the endoparasite fauna and known zoogeographical patterns for marine free‐living organisms (e.g. prey that are included in the life cycles of endoparasites). Location Fish were captured at nine localities along the Pacific coast of South America, from 11° S in the centre of the Peruvian coast, to 52° S in southern Chile, and also at two localities in the Atlantic Ocean, at 43° S in Argentina, and 34° S in South Africa. Methods From April to September 2003 and April to August 2004, 626 fish were captured. Endoparasites and diet were examined following traditional methods. Cluster analyses were used to evaluate the distribution patterns of the endoparasite communities, and to evaluate similarities in the prey composition per locality. Results The endoparasite fauna of S. capensis consisted of four species widely distributed along the Pacific coast: Ascarophis cf. sebastodis, Anisakis sp., Corynosoma australe, and Pseudopecoelus sp. Other parasites were distributed only in some geographical areas. The species richness of the parasite communities increased with latitude along the Pacific coast, while parasite communities from Argentina and South Africa showed low species richness. Cluster analyses based on endoparasite composition and on prey composition grouped localities in a way consistent with known biogeographical areas for marine free‐living organisms. Main conclusions The endoparasites of S. capensis exhibit a pattern associated with known biogeographical areas for free‐living organisms. The latitudinal increase in endoparasite community richness is associated with changes in prey composition (intermediate hosts) and also possibly with the presence of definitive hosts. Therefore, the biogeographical patterns of prey are considered key determinants of the endoparasite community structure of the host.     

Pflanzengesellschaften Der Küstendünen Von Argentinien,Uruguay Und Südbrasilien

Summary The study on the vegetation of the coastal dunes and sandy beaches of Argentine, Uruguay and southern Brazil deals with the following plant communities:¹²⁾ 1. Cakiletea maritimae Tx. et Prsg. ap. Tx. 1950 - p. 221 Halo- and nitrophil plant communities on tidal drift of the holarctic sea shores; in Argentine and Uruguay represented by the neophyticCakile maritima on fringes of tidal drift in the area of the Calycero-Panicetum racemosi. 2. Spartinetum coarctatae Cabr. 1941 - p. 222 Plant community consisting mainly of the sparse, perennial tussocks ofSpartina coarctata, which settles on the salt-water moistened sandy beach above the MHW, flooded only by spring tides; coast of Argentine and Uruguay in the area of the Senecioni-Panicetum urvilleani and the Calycero-Panicetum racemosi. 3. Sporoboletea rigentis (prov.) 3.1 Sporoboletalia rigentis (prov.) - p. 236 Perennial plant communities on the mobil dunes in the arid to semiarid, temperate to subtropical zones (see fig. 2) of the coast and in the interior of Argentine. 3.11 Sporoboli-Panicion urvilleani all. nova - p. 236 Thin plant communities formed mainly by grasses with subterranean stolones, on dunes with intense accumulation of sand. 3.111 Panico-Sporoboletum rigentis (Cabr. 1941) emend. - p. 207–208 On dunes of the arid temperate area of the coast and in the arid to semi-arid, temperate to subtropical interior of Argentine. This association probably will have to be divided in two or three associations, when more information on the dunes of the interior is obtainable. 3.112 Senecioni-Panicetum urvilleani ass. nova - p. 210–211 On coastal dunes in the semi-arid zone of Argentine, from Bahía Blanca to Necochea. 3.12 Sporoboli-Baccharidion (prov.) - p. 237 Sparsely covering communities of dwarf shrubs and grasses on dunes with little sand accumulation. 3.121 Sporoboli-Baccharidetum divaricatae ass. nova - p. 224–225 On the coastal dunes in the arid (to subarid) temperate zone of Argentine; with some floristical affinity to the Baccharidi-Androtrichion (Baccharis genistifolia, Poa lanuginosa), but predominating elements of the Sporoboletea. 3.122 Sporoboli-Psiletum spartioidis ass. nova - p. 225 The community, formed mainly byPsila spartioides Sporobolus rigens andGlycyrrhiza astragalina, settles on dunes in the arid temperate South of the Prov. of Mendoza. AsCabreras's (1945) andCano & Movia's (1967) fitosociological tables show, the communities on fossil dunes in the western part of the Prov. of Buenos Aires and in the South of San Luis, where sometimesPanicum urvilleanum andHyalis argentea grow together withElyonurus muticus, Poa ligularis, Aristida jubata and other species, cannot be placed in the Sporoboletea rigentis, but are related with other communities of the “steppe”. In the same area the Panico-Sporoboletum rigentis can be found on dunes that recovered movement by influence of man (Cabrera 1945). 4. Panicetea racemosi cl. nova 4.1 Panicetalia racemosi ord. nov. 4.11 Panicion racemosi all. nova Thin, evergreen communities consisting principally of geophyta rhizomatosa, which settle on coastal dunes with intense accumulation of sand; distributed mainly over the humid to perhumid, temperate to subtropical regions of Argentine, Uruguay and southern Brazil. 4.111 Calycero-Panicetum racemosi (Cabr. 1941) emend.- p. 212–213, 238 Grows on the coastal dunes of Argentine and Uruguay in a humid to perhumid temperate climate. 4.112 Philoxero-Panicetum racemosi ass. nova - p. 214–215, 238 Regional community on the coastal dunes in the perhumid subtropical climate of Río Grande do Sul. Also as an initial phase of succession on dunes in the tropical area, where it merges with communities of the Canavaletea maritimae. 4.113 Paspalo-Philoxeretum portulacoidis (Hueck 1955) emend. - p. 223 Community of the fordunes, consisting almost exclusively ofPhiloxerus portulacoides andPaspalum vaginatum; narrowly related to the Philoxero-Panicetum racemosi in the subtropical area, and to the Canavaletea maritimae in the tropical zone. 5. Canavaletea maritimae cl. nova - p. 239 Perennial evergreen plant communities, which consist principally of geophyta and chamaephyta with long stolones creeping below or above the soil surface; on dunes and sandy beaches of all the tropical sea shores throughout the world. In America distributed from Florida and the Bermudas Islands southward to Santa Catarina (Laguna). Still cannot be established orders and alliances. 5.001 Acicarpho-Alternantheretum maritimae ass. nova - p. 219–220 Community of the beach banks, known from the Brazilean coast from Santa Catarina to Cabo Frío. 5.002 Spartinetum ciliatae Hueck 1955 - p. 217 On the coastal dunes of tropical southern Brazil. The community probably is to be divided in regional associations, e.g.: Senecioni-Spartinetum ciliatae (prov.) - p. 239 From Santa Catarina to Paraná. Plantagino-Spartinetum ciliatae (prov.) - p. 239 On the shore of S?o Paulo, and probably northward. According to literature,Spartina ciliata andAcicarpha spathulata are distributed along the american coast only,Alternanthera maritima is to be found also in Westafrica; the Canavaletea maritimae of India, Malaysia, Indonesia, Oceania, and the Philipines are differentiated bySpinifex squarrosus. Pedley & Isbell (1971) indicated two north-australian fordune communities withIpomoea pes-caprae, Oenothera drummondii, Tridax procumbens andSpinifex longifolius. On coastal dunes on HawaiiIpomoea pes-caprae is associated withNama sandwicense. Tribulus cistoides, Vigna marina andCuscuta sandwichiana (Knapp 1965). 6. Dwarf-Shrub Communities 6.01 Baccharidi-Androtrichion all. nova - p. 240 Plant communities with predominance of dwarf shrubs, which form a kind of heath on fixed dunes with no or with only little sand accumulation along the atlantic coast from Argentine (Prov. of Buenos Aires) to southern Brazil (Santa Catarina). 6.011 Hyalidi-Baccharidetum genistifoliae (prov.) - p. 226 This community represents the “Heath ofBaccharis” in the semiarid temperate part of the coast of the Prov. of Buenos Aires; it is syndynamically related to the Senecioni-Panicetum urvilleani; still unsufficiently studied. 6.012 Androtricho-Baccharidetum genistifoliae (Cabr. 1941) emend. - p. 227–228 Baccharis Heath of the coastal dunes in the humid to perhumid temperate area of the Prov. of Buenos Aires; follows the Calycero-Panicetum racemosi in succession. 6.013 Androtricho-Baccharidetum gnaphalioidis ass. nova - p. 228–229 On the dunes in the perhumid temperate to subtropical area of the coast of Uruguay and Río Grande do Sul, where in succession it follows the Calycero-Panicetum (var. of Philoxerus) and the Philoxero-Panicetum racemosi. 6.014 Androtricho-Baccharidetum leucopappae (prov.) - p. 229–230 Plant community till now only known as fragments, which settle on the dunes in the northern, perhumid subtropical area of the coast of Río Grande do Sul and in the South of Santa Catarina; syndynamically related to the Philoxero-Panicetum racemosi. The sociological position of theBaccharis Heathes among plant communities is still unknown; by species likeMargvricarpus pinnatus andAchyrocline satureioides, Baccharis rufescens, Solidago chilensis, Aster calendulaceus and others, they may be related to communities of the interior, e.g. to the Elyonuro-Panicetum racemosi Mart.-Crov. 1962. Similar communities were found in Uruguay and in Río Grande do Sul, but they are not yet sufficiently studied that their systematic place might be judged.

---

Resúmen El estudio de la vegetación de las playas arenosas y dunas maritimas de la Argentina, del Uruguay y del Brasil Meridional abarca las siguientes comunidades vegetales:¹¹⁾ 1. Cakileteamaritimae Tx. et Prsg. ap. Tx. 1950 - p. 221 Comunidades halo y nitrófilas de las franjas de resaca en las costas marítimas holárcticas, representadas en la Argentina y en el Uruguay por el neófitoCakile maritima que ocupa franjas de resaca en el área del Calycero-Panicetum racemosi. 2. Spartinetum coarctatae Cabr. 1941 - p. 222 Comunidad vegetal formada principalmente por las aisladas matas perennes y siempreverdes deSpartina coarctata; habita las playas arenosas empapadas por agua del mar, inundadas solamente por mareas vivas, en el área templada subárida a perhúmeda de la Argentina y del Uruguay. 3. Sporoboletea rigentis (prov.) 3.1 Sporoboletalia rigentis (prov.) 236 Comunidades perennes de las dunas vivas del clima árido y subárido templado a subtropical del litoral y del interior de la República Argentina. 3.11 Sporoboli-Panicion urvilleani all. nova - p. 236 Comunidades abiertas formadas mayormente por gramíneas con estolones subterráneos, sobre dunas con ± fuerte acumulación de arena. 3.111 Panico-Sporoboletum rigentis (Cabr. 1941) emend. - p. 207–208 Sobre dunas de la costa marítima y del interior en el clima árido. Al disponer de mas observaciones, probablemente habría que desmembrar la asociación. 3.112 Senecioni-Panicetum urvilleani ass.nova - p. 210–211 Sobre dunas marítimas del clima subárido templado (Bahía Blanca a Necochea). 3.12 Sporoboli-Baccharidion (prov.) - p. 237 Comunidades ± abiertas con predominancia de arbustos enanos y gramíneas, sobre dunas con poca acumulación de arena. 3.121 Sporoboli-Baccharidetum divaricatae ass. nova - p. 224–225 Sobre dunas marítimas del clima árido (a subárido) templado; con alguna afinidad florística a las comunidades del Baccharidi-Androtrichion; dominan, sin embargo, los elementos de los Sporoboletea rigentis. 3.122 Sporoboli-Psiletum spartioidis ass. nova - p. 225 La comunidad, pobre en especies y con predominancia dePsila spartioides ySporobolus rigens, habita dunas en el árido sur de la Prov. de Mendoza. Las comunidades conElyonurus muticus de las dunas fósiles en el oeste de la Prov. de Buenos Aires y en el sur de la Prov. de San Luis, las que en parte contienenPanicum urvilleanum yHyalis argentea, no pueden incorporarse en los Sporoboletearigentis, según permiten reconocer las tablas sociológicas deCabrera (1945) y deCano & Movia (1967), sino que están relacionadas con otras comunidades de la “estepa”. En la misma zona se encuentra el Panico-Sporoboletum rigentis sobre dunas vivas que por la influencia del hombre volvieron a moverse (Cabrera 1945). 4. Panicetea racemosi cl. nova 4.1 Panicetalia racemosi ord. nov. 4.11 Panicion racemosi all. nova - p. Comunidades siempreverdes de poca cobertura, formadas principalmente por geophyta rhizomatosa, que habitan las dunas marítimas con ± fuerte acumulación de arena en el área húmeda a perhúmeda templada a subtropical de la Argentina, del Uruguay y del Brasil Meridional. 4.111 Calycero-Panicetum racemosi (Cabr. 1941) emend.- p. 212–213,238 Comunidad de las dunas marítimas argentinas y uruguayas en el clima húmedo a perhúmedo templado. 4.112 Philoxero-Panicetum racemosi ass. nova - p. 214–215,238 Comunidad regional de las dunas en el clima perhúmedo subtropical del litoral de Río Grande do Sul. Como fase pionera del desarrollo de la vegetación se halla también sobre dunas del área tropical, donde queda, por lo demas, absorbida por las comunidades de los Canavaletea maritimae. 4.113 Paspalo-Philoxeretum portulacoidis (Hueck 1955) emend. - p. 223 Comunidad de las antedunas, compuesta casi exclusivamente porPaspalum vaginatum yPhiloxerus portulacoides; en el área subtropical estrechamente relacionada con el Philoxero-Panicetum racemosi, en la zona tropical con los Canavaletea maritimae. 5. Canavaletea maritimae cl. nova - p. 239 Comunidades perennes y siempreverdes, formadas principalmente por geófitos y caméfitos provistos de largos estolones aéreos o subterráneos, sobre dunas y cordones de playa de todas las costas tropicales. En America se extienden desde Florida y las Islas Bermudas hasta el extremo sur del Estado de Santa Catarina. Todavía no se pueden establecer ordenes y alianzas. 5.001 Acicarpho-Alternantheretum maritimae ass. nova - p. 219–220 Comunidad de cordon de playa, conocida hasta ahora para la costa brasile?a desde Santa Catarina hasta Cabo Frío. 5.002 Spartinetum ciliatae Hueck 1955 - p. 217 Comunidad de las dunas maritimas del sur del Brasil, la que en base de observaciones mas detalladas se desmembraría en asociaciones regionales, por ejemplo: Senecioni-Spartinetum ciliatae (prov.) - p. 239 Dunas marítimas de Santa Catarina hasta Paraná. Plantagino-Spartinetum ciliatae (prov.) - p. 239 Dunas marítimas de S?o Paulo o Paraná al norte. Según la literatura,Spartina ciliata yAcicarpha spathulata están restringidas a América, el área deAlternanthera maritima abarca America y la costa occidental de Africa, y los Canavaletea maritimae de la India, de Malaysia, Indonesia, Oceania y de las Filipinas se distinguen porSpinifex squarrosus. Del norte de Australia se indicaron dos comunidades de la anteduna conIpomoea pes-caprae, Oenothera drummondii, Tridax procumbens ySpinifex longifolius (Pedley & Isbell 1971). Sobre dunas marítimas de Hawaii,Ipomoea pes-caprae se asocia conNama sandwicense, Tribulus cistoides, Vigna marina yCuscuta sandwichiana (Knapp 1965). 6. Comunidades de Arbustos Enanos 6.01 Baccharidi-Androtrichion all. nova - p. 240 Comunidades fisionómicamente ± parecidas a las landas deCalluna yErica de Europa, con predominancia de arbustos enanos; habitan dunas fijas sin o con muy poca acumulación de arena a lo largo de la costa atlántica desde la Argentina (Prov. de Buenos Aires) hasta el sur del Brasil (Santa Catarina) bajo condiciones climáticas subáridas a perhúmedas, templadas hasta subtropicales. 6.011 Hyalidi-Baccharidetum genistifoliae (prov.) (- p. 226–227) Representante de las landas deBaccharis en la parte subárida templada de la costa bonariense, relacionado como comunidad de sucesión con el Senecioni-Panicetum urvilleani. Todavía insuficientemente estudiado. 6.012 Androtricho-Baccharidetum genistifoliae (Cabr. 1941) emend. - p. 227–228 Landa deBaccharis de las dunas en el área húmeda a perhúmeda templada de la costa bonariense, comunidad de sucesión del Calycero-Panicetum racemosi. 6.013 Androtricho-Baccharidetum gnaphalioidis ass. nova - p. 228–229 Sobre las dunas del área perhúmeda templada a subtropical de la costa uruguayense y riograndense, comunidad de sucesión del Calycero-Panicetum (var. de Philoxerus) y del Philoxero-Panicetum racemosi. 6.014 Androtricho-Baccharidetum leucopappae (prov.) - p. 229–230 Comunidad hasta ahora conocida solamente en forma de fragmentos que habitan las dunas muy pastoreadas en el área perhúmeda subtropical de la costa de Río Grande de Sul y Santa Catarina. La posición de las landas deBaccharis entre las demás comunidades vegetales todavía es incierta; especies comoMargvricarpus pinnatus yAchyrocline satureioides, Baccharis rufescens, Solidago chilensis, Aster calendulaceus y otras las relacionan probablemente con comunidades del interior, por ejemplo con el Elyonuro-Panicetum racemosi Mart.-Crov. 1962. En Uruguay y en Río Grande do Sul se hallaron comunidades mas o menos parecidas, todavía insuficientemente estudiadas para juzgar su ubicación sociológico-sistemática.

---

---

Dem Altmeister der Vegetationskunde Argentiniens, Dr.Angel Lulio Cabrera, in Verehrung gewidmet.     

Isopódos litorales de la Costa de concepción,Chile central

Littoral isopods of the coast of Concepción, Central Chile

A collection of isopods is studied from the intertidal region of the province of Concepción (Chile), located on the South American pacifics coast between 36 and 37° S latitude.

The collection consists of 11 species, two of them new for science: Ianiropsis kussakini, described here, and Janira sp., still under study. The distribution of species is, grosso modo, restricted to the central zone or south center of Chile, which seems to corroborate the opinion of some authors who consider it as a region of biogeographic transition between the Peruvian and Magellan provinces.     

Antibody responses of domestic animals to salivary antigens of Triatomainfestans as biomarkers for low-level infestation of triatomines

Hematophagous arthropods such as Triatomainfestans, the vector of Trypanosomacruzi, elicit host-immune responses during feeding. Characterization of antibody responses to salivary antigens offers the potential to develop immunologically based monitoring techniques for exposure to re-emergent triatomine bug populations in peridomestic animals. IgG-antibody responses to the salivary antigens of T.infestans have been detected in chickens as soon as 2 days after the first exposure to five adult bugs. Chickens and guinea pigs regularly exposed to this number of triatomines showed a significantly lower anti-saliva antibody titre than animals exposed to 25 adults and fifth instars of four different T.infestans strains originating from Bolivia and from Northern Chile. Highly immunogenic salivary antigens of 14 and 21 kDa were recognised by all chicken sera and of 79 kDa by all guinea pig sera. Cross-reactivity studies using saliva or salivary gland extracts from different hematophagous species, e.g. different triatomines, bed bugs, mosquitoes, sand flies and ticks, as well as chicken sera exposed to triatomines and mosquitoes, demonstrated that the 14 and 21 kDa salivary antigens were only found in triatomines. Sera from peridomestic chickens and guinea pigs in sites of known T.infestans challenge in Bolivia also recognised the 14 and 21 kDa antigens. These represent promising epidemiological markers for the detection of small numbers of feeding bugs and hence may be a new tool for vector surveillance in Chagas disease control programs.