Temnocephala rochensis Ponce de Léon, 1979, was the second of four species of Temnocephala Blanchard, 1849 to be described as ectosymbiont of ampullariid apple snails, Pomacea canaliculata (Lamarck, 1822). There have been no records of this Uruguayan species after its initial description. As part of the present study, 111 specimens of P. canaliculata were collected between 2003 and 2009. Temnocephalans found in the pallial cavity were identified as T. rochensis, occurring in single infestations, or concurrently with Temnocephala haswelli Ponce de Léon, 1989. Specimens of T. rochensis showed a conspicuous red eye pigment which faded after ethanol fixation. Important taxonomic characters of the reproductive system were evidenced by several techniques, and documented photographically for the first time for this species: 1) the typical curved cirrus of the species showing very short and stout spines; 2) the vagina with the proximal portion dilated, forming a "vesicula intermedia"; and 3) the distal portion very muscular, as well as the large and symmetrical vaginal sphincter were documented in detail with Nomarski's DIC microscopy. Eggs were observed in the suture, in the spire, and in the umbilicus of the shell; they had a short peduncle or were sessile, always with short and curved, sometimes straight apical filaments. The rounded shape of the dorsolateral 'excretory' syncytial epidermal plates had central nephridiopores. This is the first record of this species outside of Uruguay and in the State of Rio Grande do Sul, Brazil. Even with extended sampling efforts in the eastern region of Rio Grande do Sul, T. rochensis has not been found, showing a geographical distribution restricted to the southern region, close to its type locality of Laguna Negra, Uruguay.

The impact of the discovery of Temnocephala haswelli Ponce de Léon, 1989, described as ectosymbionts of ampullariid apple snails outside of Uruguay, motivated us to collect a large number of specimens of Pomacea canaliculata (Lamarck, 1822) from several localities in the southern portion of the state of Rio Grande do Sul. This species was recorded three times after its description: in a study of chromosomes, in a study about the ultrastructure of the collar receptor cells, and in a study of the Haswell glands, all conducted in Uruguay. A total of 301 specimens of P. canaliculata were collected from 1999 to 2007. Temnocephalans found in the pallial cavity were identified as T. haswelli, which occurred in single infestations or concurrently with Temnocephala iheringi Haswell, 1893. Helminths usually showed a light-orange body pigmentation and conspicuous, intense red-eye pigment. Many taxonomic characters evidenced by several techniques were documented photographically for the first time. The typical curved cirrus, approximately 90°, typical of the species, showed some variation in the width of the shaft base, whereas the first longitudinal row of spines of the introvert appeared with shorter spines. The vagina was found to be thick-walled, but not very muscular, and to have a single, large and slightly asymmetrical sphincter, with the posterior portion of slightly larger diameter. Eggs were observed in the umbilicus and along the suture, but predominantly in the body whorl of the shell. Egg peduncles were found to be very short or, most of the time, the eggs were sessile, always with a long apical filament. The rounded shape of the dorsolateral 'excretory' syncytial epidermal plates had external margins reaching the ventrolateral region of the body and eccentric nephridiopores. This is the first record of the species outside Uruguay and in Brazil.

The original description of Temnocephala iheringi Haswell, 1893 was based on specimens collected by Hermann von Ihering from undetermined ampullariid apple snails, which at that time were identified as Ampullaria sp., and sent to William H. Haswell, with the type locality simply indicated as Brazil. The type specimens studied by Haswell were not found in the scientific collections of Brazil, Europe or Australia, and should be considered lost. In 1941, Pereira & Cuocolo collected specimens from apple snails, identified as Pomacea lineata (Spix in Wagner, 1827), at two localities (Guaicurús and Salobra) in the state of Mato Grosso do Sul, central Brazil. These specimens could not be located either and should, thus, be considered lost as well. Pomacea canaliculata (Lamarck, 1822), the main host of T. iheringi in southern Brazil, is known to have a geographical distribution that reaches Uruguay and 400 km beyond the province of Buenos Aires, Argentina. Three hundred and one mollusks were collected from 1999 to 2007. Temnocephalans found in the pallial cavity presented a greenish body pigmentation (adults) and lacked eye pigment of any color, including the red-eye pigment, typical of Neotropical species of Temnocephala Blanchard, 1849; straight cirrus, with a thick band at base of the introvert' swelling; and a single, circular, asymmetric vaginal sphincter, wider in diameter in the posterior portion. As the species occurs concurrently with two other species, at least in P. canaliculata from Rio Grande do Sul, the eggs of T. iheringi could not be reliably distinguished. A redescription of the species is provided. A comparison of data from the present work with those of earlier papers published on T. iheringi from Argentina showed that the Argentinean specimens had the smallest measurements.

Temnocephala minutocirrus sp. nov., ectosimbionte sobre Cryphocricos granulosus De Carlo, 1967, é descrita para o Estado do Rio Grande do Sul. Cento e nove naucorídeos foram examinados, dos quais 36 (33%) estavam positivos para esta espécie do gênero Temnocephala Blanchard, 1849. Em uma amostra de 94 hemípteros, 49 (52%) eram ninfas de 4º instar, das quais, 6% estavam infestadas; 45 (48%) eram adultos, braquípteros 40 (18 machos e 22 fêmeas) ou macrópteros 5 (1 macho e 4 fêmeas), 67% dos quais estavam infestados (29% machos e 38% fêmeas), para esta espécie de temnocefalídeo. Ovos dos temnocefalídeos estavam fixados na face ventral do hemíptero, sobre as coxas, trocânteres e esterno, entre o primeiro, segundo e terceiro pares de pernas e na face dorsal, sobre o escutelo, clavo e hemiélitros. Temnocefalídeos juvenis e adultos sempre se apresentaram sem pigmentação corporal. Os caracteres mais distintivos da nova espécie são: 1) cirro muito curto, levemente curvo, com o 'introvert' correspondendo a 37% do comprimento total; 2) placas dorsolaterais, sinciciais 'excretoras' elípticas, com poro excretor equatorial, próximo do limite interno da placa; 3) dois pares de 'grandes glândulas do disco' (paranefrócitos?) centrais, imediatamente à frente dos testículos; 4) testículos relativamente grandes, mas desiguais em tamanho, par anterior menor, sempre na mesma zona, aqueles do mesmo lado, parcialmente sobrepostos; e 5) vagina com parede muscular fracamente desenvolvida e sem esfíncteres musculares.

Temnocephala minutocirrus sp. nov., an ectosymbiont on Cryphocricos granulosus De Carlo, 1967, is described from the State of Rio Grande do Sul, southern Brazil. One hundred and nine naucorids were examined, of which 36 (33%) were positive for this species of Temnocephala Blanchard, 1849. In one sample of 94 creeping water bugs, 49 (52%) were 4th instar nymphs, 6% of which were infested; 45 (48%) were adults, either brachypterous (40 with 18 males and 22 females) or macropterous (5 with 1 male and 4 females), 67% of which were infested (29% males and 38% females). Temnocephalan eggs were found both ventrally and dorsally: fixed on coxae, trochanters, and along the sternum between fore middle, and hind pairs of legs; basal of the abdominal area; and on the scutellum, clavus, and hemelytra. Juvenile and adult temnocephalans were always devoid of body pigmentation, and were found living on the ventral body surface, preferably over the sternum, between the middle and hind pairs of legs. The most distinctive features of this new species are: 1) unusually short cirrus, slightly curved, with introvert corresponding to 37% of its total length; 2) dorsolateral 'excretory' syncytial epidermal plates, elliptic, with excretory pore relatively equatorial, closer to inner limit of each plate; 3) two pairs of large disc gland cells (paranephrocytes?) located centrally, just ahead of testes; 4) testes relatively large, but unequal in size, anterior pair smaller, always in the same zone, those of the same side, partially superposed; and (5) vagina with weak muscular wall and without muscular sphincters.

Três espécies de aves, dois anatídeos, Dendrocygna bicolor (Vieillot, 1816) (marreca-caneleira) e Netta peposaca (Vieillot, 1816) (marrecão) e um phalacrocoracídeo, Phalacrocorax brasilianus (Gmelin, 1789) (biguá) foram coletados em vários locais na Província da Planície Costeira e no Lago Guaíba, Estado do Rio Grande do Sul. O número de aves examinadas de cada espécie de hospedeiro, assim como os valores de prevalência e intensidade média de infecção foram: 33 D. bicolor, 3%, 1 helminto/hospedeiro; 20 N. peposaca 15%, 4,3 helmintos/hospedeiro e 47 P. brasilianus 2,1%, 1 helminto/hospedeiro. O espécime coletado no biguá e um dos espécimes, entre aqueles, coletados nos marrecões estavam na cloaca. Os outros espécimes coletados nos marrecões e o único espécime coletado nas marrecas-caneleiras, respectivamente, estavam na bolsa de Fabricius. Este é o primeiro registro de P. ovatus em biguás e em marrecões. A distribuição geográfica conhecida de P. ovatus é estendida para o sul do Brasil e para o Estado do Rio Grande do Sul.

Three species of birds, two anatids, Dendrocygna bicolor (Vieillot, 1816) (Fulvous Whistling Duck) and Netta peposaca (Vieillot, 1816) (Rosy-billed Pochard), and one phalacrocoracid, Phalacrocorax brasilianus (Gmelin, 1789) (Neotropical Cormorant) were collected from several localities in the Coastal Plain Province and in Lago Guaíba, State of Rio Grande do Sul. The number of birds examined of each host species with the respective values of prevalence and mean intensity of infection of P. ovatus were: 33 D. bicolor, 3%, 1 helminth/host; 20 N. peposaca 15%, 4.3 helminths/host, and 47 P. brasilianus 2.1%, 1 helminth/host. The single specimen collected from the Neotropical cormorants and one of the specimens collected from the rosy-billed pochards, were in the cloaca. The remaining specimens from the rosy-billed pochards and the single specimen from the fulvous whistling ducks were in the bursa of Fabricius. This is the first record of P. ovatus in Neotropical cormorants and rosy-billed pochards. The known geographical distribution of P. ovatus is extended to the southernmost State of Brazil, Rio Grande do Sul.

Os nematóides do gênero Syncuaria Gilbert, 1927 são parasitos de aves das ordens Pelecaniformes, Ciconiiformes e Podicipediformes. Onze espécies são consideradas válidas neste gênero, no entanto, somente duas, Syncuaria buckleyi (Ali, 1957) Wong, Anderson & Bartlett, 1986 e Syncuaria squamata (Linstow, 1883) Wong, Anderson & Bartlett, 1986 parasitam aves do gênero Phalacrocorax Brisson, 1760. Entre 1999 e 2003 foram coletados 47 biguás, Phalacrocorax brasilianus (Gmelin, 1789) no Lago Guaíba, Município de Guaíba, Rio Grande do Sul, Brasil. Oito destas aves estavam infectadas por S. squamata. A prevalência e a intensidade média de infecção na amostra foram de 8,5% (8 de 47) e 2,5 helmintos/hospedeiro, respectivamente. Esta comunicação amplia a distribuição geográfica conhecida dos helmintos do gênero Syncuaria para o Brasil.

The nematodes of the genus Syncuaria Gilbert, 1927 are parasites of birds of the orders Pelecaniformes, Ciconiiformes, and Podicipediformes. Eleven species are considered valid in this genus, however, two species, Syncuaria buckleyi (Ali, 1957) Wong, Anderson & Bartlett 1986 and Syncuaria squamata (Linstow, 1883) Wong, Anderson & Bartlett, 1986 are parasites of birds of the genus Phalacrocorax Brisson, 1760. Between 1999 and 2003, 47 Neotropical Cormorants, Phalacrocorax brasilianus (Gmelin, 1789) were collected at Lago Guaíba, Municipality of Guaíba, Rio Grande do Sul, Brazil. Eigth of these birds were infected with S. squamata. The prevalence and the mean intensity of infection were 8.5% (8 of 47) and 2.5 helminths/host, respectively. This communication extends the known geographical distribution of nematodes of the genus Syncuaria to Brazil.

O presente trabalho é parte de um estudo maior sobre a helmintofauna dos cormorões Neotropicais conhecidos no Brasil como biguás, Phalacrocorax brasilianus (Gmelin, 1789), particularmente, no Estado do Rio Grande do Sul. Os nematóides que foram encontrados soltos no proventrículo/ventrículo ou em grupos compostos por adultos de várias idades e larvas de vários estágios (L3 e L4), formando granulomas eosinofílicos tiveram prevalência de 100% em 47 biguás do Lago Guaíba, Município de Guaíba. A morfologia dos lábios e dos interlábios, o padrão de distribuição das papilas caudais em machos examinados com microscópio eletrônico de varredura (MEV) e as extremidades dos espículos permitiram a determinação da espécie como Contracaecum rudolphii Hartwich, 1964 sensu lato (s. l.). Este é o primeiro registro de C. rudolphii na região Sul do Brasil.

The present report is part of a larger study on the helminth fauna of Neotropical Cormorants, Phalacrocorax brasilianus (Gmelin, 1789) in Brazil, particularly, in the southernmost State of Rio Grande do Sul. The nematodes which were found loose in the proventriculus/ventriculus or in groups of adults of different ages and of L3 and L4 larval stages, forming eosinophylic granulomas had a prevalence of 100% in 47 Neotropical cormorants from Lago Guaíba, Municipality of Guaíba. The morphology of the labia/interlabia, the distribution pattern of the caudal papillae in males examined under scanning electron microscopy (SEM), and the tips of the spicules allowed determination of the species as Contracaecum rudolphii Hartwich, 1964 sensu lato (s. l.). This is the first record of C. rudolphii in southern Brazil.

Uma nova espécie do gênero Andracantha Schmidt, 1975, parasita de biguás (cormorões neotropicais), Phalacrocorax brasilianus (Gmelin, 1789), é descrita e comparada com as outras seis espécies atualmente incluídas no gênero. A nova espécie difere das demais espécies previamente conhecidas de Andracantha por ter duas inflações na região anterior do corpo e por ter testículos em tandem na região central do corpo. Estas diferenças também são responsáveis pela emenda na diagnose do gênero agora proposta. Pela primeira vez é documentada a pigmentação alaranjada de acantocéfalos recém coletados do intestino, em qualquer espécie do gênero. Este é o primeiro registro de espécimes adultos do gênero Andracantha na América do Sul.

A new species of the genus Andracantha Schmidt, 1975, parasite of Neotropical cormorants, Phalacrocorax brasilianus (Gmelin, 1789), is described and compared to the other six species currently placed in the genus. The new species differs from the previously known species of Andracantha by having two inflations in the anterior region of the trunk and by having the testes in tandem in the central region of the body. These differences were also responsible for the diagnosis emendation of the genus now proposed. The orange pigmentation of the acanthocephalans recently collected from the intestine is documented for the first time in a species of this genus. This is the first record of adult specimens of any species of Andracantha in South America.

Temnocephala trapeziformis sp. nov., ectosimbionte sobre Trichodactylus fluviatilis Latreille, 1828 é descrita para o Estado do Rio Grande do Sul, região sul do Brasil. Sessenta e oito caranguejos foram examinados, sendo que 61 (89,7 %) estavam positivos para esta espécie do gênero Temnocephala Blanchard, 1849. Posturas estavam localizadas, sobre as pleuras da carapaça, nas cavidades orbitais e no quarto par de pereiópodos, locais onde também foram encontrados espécimes jovens e adultos. Os temnocefalídeos sempre se apresentaram sem pigmento corporal, embora o pigmento vermelho dos olhos tenha sido preservado nos espécimes fixados em formalina 10% fosfato tamponada (90ºC). Os caracteres mais distintos da nova espécie são: 1) a forma e o tamanho do cirro e as características do 'introvert', 2) as placas sinciciais 'excretoras' trapeziformes, com o nefridióporo sempre deslocado para o canto inferior interno de cada placa, e 3) o número, o tamanho e a distribuição das glândulas produtoras de rabdites, observadas em espécimes muito jovens.

Temnocephala trapeziformis sp. nov., ectosymbiont on Trichodactylus fluviatilis Latreille, 1828 is described from the State of Rio Grande do Sul, southern Brazil. Sixty-eight crabs were examined, of which 61 (89.7 %) were positive for this species of the genus Temnocephala Blanchard, 1849. Eggs, as well as adult and young specimens, were found on the pleural areas of the carapace, in the orbital cavities, and, usually, on the fourth pair of pereiopods. The temnocephalans were always devoid of body pigmentation, although they kept the red eye pigment, undiluted in specimens fixed by hot (90ºC) phosphate buffered 10% formalin. The most distinctive characters of the new species are: 1) the shape and size of the cirrus and the characteristics of its introvert section; 2) the trapezoidal shape of the dorsolateral post-tentacular 'excretory' epidermal syncytial plates, with the nephridiopore in the lower inner corner of the plate; and 3) the number, size, and distribution of the rhabdite producing glands, as observed in very young specimens.

Este é o primeiro registro de uma espécie do gênero Echinuria Soloviev, 1912, em hospedeiros anatídeos na América do Sul, causando granulomas. É, também, a primeira descrição detalhada e o primeiro registro de Echinuria uncinata (Rudolphi, 1819) Soloviev, 1912, para a América do Sul, e o primeiro registro de um nematóide acuarióideo em Netta peposaca (Vieillot, 1816). Cinqüenta e dois marrecões foram examinados para helmintos nas localidades de Fazenda Sossego e Ponta da Antena, Município de Santa Vitória do Palmar, Estado do Rio Grande do Sul, região Sul do Brasil e Alvear, Província de Corrientes, região Norte da Argentina. As amostras foram obtidas no período de 2003 a 2004. Imediatamente após o abate, cada ave foi congelada em gelo seco. As aves foram separadas por sexo, pesadas e medidas. O estado de maturidade de cada ave foi avaliado (juvenil ou adulto) com base na presença ou ausência da bolsa de Fabricius. Os granulomas, contendo os nematóides, estavam situados na base do esôfago quase junto à junção com o proventrículo. Duas aves estavam positivas, com um (fistulado) e dois granulomas, respectivamente. Uma das aves era proveniente do Brasil (pólo de invernia na planície costeira do Estado do Rio Grande do Sul). A outra da região Norte da Argentina, capturada em um dos pólos de nidificação, antes de empreender sua viagem em direção à costa brasileira ao longo de sua rota de migração. A prevalência da infecção foi de 3,8% e a intensidade média de infecção de 7,2. A morfometria de machos e de fêmeas permitiu a identificação dos espécimes como E. uncinata.

This is the first report of a species of Echinuria Soloviev, 1912, on anatid hosts in South America, causing granulomas. It is also the first detailed description and record of a species of Echinuria, for South America in the Rosy-billed Pochard, Netta peposaca (Vieillot, 1816). Fifty-two rosy-billed pochards were examined for helminths in the Municipalities of Santa Vitória do Palmar (locality of Fazenda Sossego) and (locality of Ponta da Antena), State of Rio Grande do Sul, Brazil, and Alvear, Province of Corrientes, northern Argentina. Samples were obtained from 2003 to 2004. After the catch each bird was immediately frozen with dry ice. Prior to necropsy birds were sexed, weighted, measured, and the state of maturity (juvenile or adult) determined, based on the presence or absence of a bursa of Fabricius. The granulomas with the nematodes were found in the proximal esophagus at the junction with the proventriculus. Two birds had one (fistulated) and two granulomas, respectively. One of the birds was from the wintering grounds along the coastal region in the State of Rio Grande do Sul, southern Brazil. The other, from one of the breeding grounds in northern Argentina, was captured before the trip to the wintering grounds along the migratory flyway. Prevalence was 3.8% while the mean intensity of infection was 7.2. Morphometry of males and females and the comparison with previous descriptions and illustrations allowed the identification of the present specimens as E. uncinata.

Baratas-d'água (heterópteros aquáticos), Belostoma dilatatum (Dufour, 1863), foram coletadas em canais ao lado de taipas e córregos em plantações de arroz, no Município de Eldorado do Sul, grande Porto Alegre, Estado do Rio Grande do Sul, região Sul do Brasil. Cinco espécimes foram examinados com o objetivo de detectar a presença de metacercárias de trematódeos digenéticos. Quatro deles (80%) estavam positivos para cistos de metacercárias de Stomylotrema vicarium Braun, 1901. As intensidades de infecção variaram de 1 a 16 metacercárias por hospedeiro (média de 7,6). Os cistos eram esbranquiçados, translúcidos, e estavam soltos entre as vísceras, nas cavidades abdominal e torácica dos hemípteros. Belostoma dilatatum é um novo registro de hospedeiro para metacercárias de trematódeos digenéticos da família Stomylotrematidae, assim como este é o primeiro registro de hemípteros aquáticos servindo como segundo hospedeiro intermediário de trematódeos digenéticos no Brasil.

Giant water bugs (aquatic Heteroptera), Belostoma dilatatum (Dufour, 1863), were collected in rice plantation water canals, in the Municipality of Eldorado do Sul, outskirts of Porto Alegre, State of Rio Grande do Sul, southern Brazil. Five specimens were dissected with the objective of finding metacercariae of digenetic trematodes. Four of them (80%) were positive for metacercarial cysts of Stomylotrema vicarium Braun, 1901. The intensities of infection varied from 1 to 16 metacercariae per host (average 7.6). The cysts were whitish, translucent, and found loose among the viscera, in the abdominal and thoracic cavities. Belostoma dilatatum is a new host record for metacercarial cysts of stomylotrematid digenetic trematodes and this is the first time that aquatic hemipterans are recorded as second intermediate hosts of digenetic trematodes in Brazil.

Temnocephala lutzi Monticelli, 1913, ectosimbionte sobre caranguejos braquiúros de água doce do gênero Trichodactylus Latreille, 1828, é assinalada pela primeira vez no Estado do Rio Grande do Sul, região sul do Brasil. Duzentos e setenta e nove caranguejos foram examinados: 211 de Trichodactylus panoplus (von Martens, 1869) e 68 de Trichodactylus fluviatilis Latreille, 1828, dos quais 51 (24,17%) e 28 (41,17%) estavam positivos para T. lutzi, respectivamente. Caranguejos das duas espécies apresentaram posturas de T. lutzi com os ovos fixados, exclusivamente, no interior das câmaras branquiais, sobre o assoalho e/ou na face interna das brânquias. Espécimes juvenis e adultos foram encontrados dentro e fora das câmaras branquiais. Os temnocefalídeos sempre se apresentaram sem pigmento corporal, embora o pigmento vermelho dos olhos tenha sido preservado nos espécimes fixados em formalina. Os cirros em T. lutzi apresentaram-se com a forma típica da espécie, as placas sinciciais dorsolaterais, pós-tentaculares 'excretoras', demonstradas através de duas técnicas especiais (nitrato de prata e MEV), apresentaram a forma elíptica com o nefridióporo central.

Temnocephala lutzi Monticelli, 1913, ectosymbiont on brachyuran freshwater crabs of the genus Trichodactylus Latreille, 1828 is recorded for the first time in the State of Rio Grande do Sul, southern Brazil. Two hundred and seventy-nine crabs of two species were examined: 211 Trichodactylus panoplus (von Martens, 1869) and 68 Trichodactylus fluviatilis Latreille, 1828 of which 51 (24.17%) and 28 (41.17%) were positive for T. lutzi, respectively. Crabs of both species carried eggs fixed, exclusively, on the floor of the branchial chambers and/or on the lower side of the gills. Adult as well as young specimens were found inside and outside the branchial chambers. The temnocephalans were always devoid of body pigmentation, although they kept the red eye pigment undiluted in specimens fixed by formalin. The cirrus of T. lutzi showed the typical shape for the species, while the dorsolateral, post tentacular 'excretory' syncytial plates, demonstrated by two special techniques (silver nitrate staining and SEM), appeared with an elliptical shape and a central nephridiopore.

Uma nova espécie de Temnocephala Blanchard, 1849 é descrita para o sul do Brasil, ectosimbionte sobre baratas-d'água (hemípteros aquáticos), Belostoma spp. da região metropolitana de Porto Alegre, Estado do Rio Grande do Sul. Vários hemípteros examinados estavam positivos para esta espécie do gênero Temnocephala, inclusive com posturas sempre localizadas na face ventral entre os dois primeiros pares de apêndices locomotores, e entre o primeiro par de pernas e o rostro. Espécimes adultos e jovens de tamanhos variados também foram sempre encontrados na face ventral do hemíptero. Os vermes adultos eram pigmentados (marrom-esverdeado), mimetizando a cor do exoesqueleto de seus hospedeiros. A nova espécie é semelhante à Temnocephala decarloi Moretto, 1978, descrita da Argentina, única espécie conhecida do gênero já encontrada sobre hemípteros belostomatídeos, por ter um cirro extremamente longo e curvo, mas difere desta por ter a porção distal do 'introvert' sem a forma típica de um cachimbo ('full-bent') como ilustrada pelo autor na descrição original.

A new species of Temnocephala Blanchard, 1849 is described from southern Brazil, ectosymbiont on giant water bugs (aquatic hemipterans), Belostoma spp. from the greater Porto Alegre, State of Rio Grande do Sul. Some hemipterans examined were positive for this species of Temnocephala and carried bunches of eggs between the first two pairs of legs and between the first pair of legs and the rostrum, as well as adult and young specimens. The adults were darkly pigmented (greenish-brown), mimetizing the color of the hemipteran hosts. The new species is similar to Temnocephala decarloi Moretto, 1978, from Argentina, the only other species of Temnocephala from belostomatid hemipterans known to date, by having an extra long and curved cirrus, but differs by having the distal portion of the introvert not bent as a 'full-bent' smoking pipe-like, as the author depicted originally for T. decarloi.

The observation of pigmentation alteration in isopod crustaceans induced by acanthocephalans, known as pigmentation dystrophy, has been documented in North America in species of the aquatic genera Asellus Geoffroy, 1764, Lirceus Rafinesque-Schmaltz, 1820, and Caecidotea Packard, 1871, and in Europe, in Asellus. Recently, three depigmented specimens of Atlantoscia floridana (van Name, 1940), a terrestrial isopod, occurring from >Florida, USA to northern Argentina were found showing pigmentation dystrophy and harboring larval acanthocephalans. Photographic documentation of live and preserved, infected isopods is presented. Morphometric data and photomicrographs of the male, unencysted cystacanth specimen which allowed its placement in the genus Centrorhynchus Lühe, 1911 are presented. This is the first record of the phenomenon of pigmentation dystrophy in terrestrial isopod crustaceans, the first record of A. floridana infected by an acanthocephalan and the first record of a species of Centrorhynchus in a terrestrial isopod.