Stenella Clymene Research Articles

A Quantitative Analysis of Microplastics in the Gastrointestinal Tracts of Odontocetes in the Southeast Region of the United States.

Microplastics (<5 mm in diameter) are ubiquitous in the oceanic environment, yet microplastic accumulation in marine mammals is vastly understudied. In recent years, efforts have been made to document microplastic profiles in odontocetes. The objective of the present study was to describe and quantify microplastics in the gastrointestinal (GI) tracts of deceased odontocetes that stranded in the southeastern United States. Our study included 24 bottlenose dolphins (Tursiops truncatus), two pygmy sperm whales (Kogia breviceps), one pantropical spotted dolphin (Stenella attenuata), one short-snouted spinner dolphin (Stenella clymene), one Risso's dolphin (Grampus griseus), and one dwarf sperm whale (Kogia sima) obtained from stranding networks in Texas, Alabama, Florida, and Puerto Rico. Contents found in the GI tracts, namely, the stomach and portions of the intestinal tract, were subjected to a laboratory procedure to isolate microplastics. The physical characteristics of microparticles were analyzed with a stereomicroscope, and microplastics were classified by polymer type via Fourier-transform infrared spectroscopy. There was an average of 47.6 ± 41.4 microparticles, ranging from 1 to 193 items per stomach. More specifically, there was an average of 5.6 ± 4.7 microplastics per stomach. The predominant morphologies, colors, and polymer types were fibers, white-colored items, and polyester, respectively. This research contributes to the current knowledge of microplastic exposure in top marine mammal predators and sets the stage for further exploration into the associated risks of microplastics in odontocetes within the United States and worldwide. Environ Toxicol Chem 2024;43:1260-1273. © 2024 SETAC.

First record of the Clymene dolphin (Stenella clymene Gray, 1850) in Costa Rican waters

First record of the Clymene dolphin (Stenella clymene Gray, 1850) in Costa Rican waters

Molecular Detection of Pathogenic Leptospira sp. in Cetaceans from the Brazilian Coast

Leptospirosis is a zoonosis with ubiquitous distribution caused by spirochetes belonging to the genus Leptospira sp., endemic mainly in tropical and subtropical regions of the world and capable of infecting domestic animals, free-living animals, and humans. Although well documented in terrestrial animals and humans, little information is available on its distribution and impact on marine animals. There are few studies assessing cetaceans’ health status, and even scarcer are those focused on leptospirosis research. In this context, considering the One Health approach, the present study aimed to investigate the occurrence of pathogenic Leptospira sp. in cetaceans on the Brazilian coast. Kidneys of 142 cetaceans belonging to 19 species were collected. DNA was extracted, and the diagnosis was performed by LipL32-polymerase chain reaction. Genetic characterization was conducted based on secY gene sequencing. Pathogenic Leptospira sp. DNA was detected in 14.8% (21/142) of the tested cetaceans, with coastal species presenting a significantly higher frequency (p-value = 0.03) of infected individuals (25%, 17/68) than oceanic species (7.5%, 4/53). It was possible to amplify and sequence three strains (one for Sotalia guianensis, one for Stenella clymene, and one for Pontoporia blainvillei), all of them identified as Leptospira interrogans, with high similarity with sequences from Icterohaemorrhagiae serogroup. Phylogenetic analysis revealed sequences from the present study grouped in species-specific unique clusters but very close to pinnipeds in the same area, evidencing the presence of two distinct haplotypes circulating on marine mammals in the region. We could demonstrate that cetaceans can act as carriers of pathogenic leptospires. Moreover, the proximity with anthropogenic areas could play an important role in leptospirosis’ dynamics of transmission in a One Health context.

Cetaceans of the oceanic northern Gulf of Mexico: Distributions, group sizes and interspecific associations

The Gulf of Mexico is a subtropical ocean basin with a diverse oceanic cetacean community. Cetacean research in the Gulf of Mexico has been driven by mandates of the US Marine Mammal Protection Act as well as concerns over the rapidly expanding oil and natural gas industry and related potential threats (e.g. seismic surveys, increased ship traffic, oil spills). Previously, cetacean distribution and abundances for specific Gulf of Mexico areas or species have been described based on work over periods of several years, and recently abundance estimates were made for the entire oceanic northern Gulf of Mexico (1996-2001). For each cetacean species, the paper describes distribution, group size, associated sea surface temperature and water depth and interspecific associations based on surveys conducted over 11 years that span the entire northern Gulf of Mexico. This dataset is the most comprehensive to date for the oceanic northern Gulf. Nine ship surveys totalling 45,462km of effort were conducted during spring seasons (1991-2001) in continental shelf-edge and oceanic waters ( 100m) of the northern Gulf of Mexico. Eighteen species were identified from 1,868 sightings. Cetaceans were found throughout the area although some species had localised distributions or occurred in restricted ranges of water depths. Spinner dolphins (Stenella longirostris) had the largest mean group size (n = 40, x – = 151.5, SE = 30.90), followed by melon-headed whales (Peponocephala electra), clymene dolphins (S. clymene), pantropical spotted dolphins (S. attenuata), Fraser’s dolphins (Lagenodelphis hosei) and striped dolphins (S. coeruleoalba) (range of means 46.1-99.6). Beaked whales (Ziphiidae), Bryde’s whales (Balaenoptera edeni/brydei), sperm whales (Physeter macrocephalus) and pygmy/dwarf sperm whales (Kogia spp.) were found in the smallest groups (x – &lt; 3). Twenty-seven sightings (1.4% of all sightings) were composed of two cetacean species. Common bottlenose dolphins (Tursiops truncatus) were recorded in mixedspecies groups with more species than any other cetacean. Forty-five cetacean sightings (2.4% of all sightings) were associated with at least one bird species, and 21 (1.1% of all sightings) were associated with schools of fish. Contrary to previous reports, pantropical spotted dolphins were observed in association with both fish (including surface tunas) and seabirds, although to a lesser extent than for other tropical oceans. No mixed pantropical spotted and spinner dolphin groups were sighted despite their regular co-occurrence in other tropical oceans.

Occurrence and distribution of cetaceans off northern Angola, 2004/05

The occurrence and distribution of cetacean species off northern Angola was examined using dedicated survey data and incidental sighting records. Dedicated surveys for cetaceans were carried out during two geophysical seismic surveys off northern Angola between August 2004 and September 2005. A total of 3,268hr of survey effort data were collected, resulting in 779 on-effort cetacean sightings. There were 263 sightings reported off-effort and incidentally from other platforms and sports fishermen. With 21 cetacean species confirmed, the cetacean community off northern Angola is diverse and primarily tropical in characteristic, comprising four species of baleen whale, two sperm whale species, at least two beaked whale species, and 13 species of delphinid. Humpback and sperm whales were the most frequently recorded cetaceans. The occurrence of humpback whales was significantly higher within neritic waters, and during the winter and spring months in association with seasonal occupancy of their West African breeding grounds. Sperm whales were recorded in water depths exceeding 1,000m and demonstrated significant seasonality, with peak occurrence during the summer and autumn. Atlantic spotted dolphins and common dolphins (Delphinus sp.) were the most numerous delphinids recorded, with spotted dolphins showing a significant seasonal peak during the spring and summer, and common dolphins in the winter. Other species recorded included fin whale, sei whale, Bryde’s whale, dwarf sperm whale, Cuvier’s and Mesoplodon beaked whales, killer whale, short-finned pilot whale, false killer whale, melon-headed whale, Atlantic humpback dolphin, rough-toothed dolphin, Risso’s dolphin, bottlenose dolphin, Pantropical spotted dolphin, spinner dolphin, Clymene dolphin and striped dolphin. Further research is required to document the cetacean community in Angola, particularly given the unknown threat from fishery bycatch and the increasing level of oil and gas exploration in the region.

CLYMENE DOLPHIN STRANDING EVENT IN PERNAMBUCO STATE, NORTHEAST COAST OF BRAZIL

On 30 th January 2021, one dolphins was reported stranded at Ipojuca municipality in Pernambuco State, Brazil. The teams from Ecoassociados and from Instituto Chico Mendes de Conservação da Biodiversidade/Centro Nacional de Pesquisa e Conservação de Mamíferos Aquáticos attended to the rescue call as representatives of the Rede de Encalhes e Informações de Mamíferos Aquáticos do Nordeste do Brasil. The individual showed a high level of stress and muscular spasms, was soon in shock and died around 90 minutes later. After further analyses and necropsy procedure, the teams identified the individual as an adult female Stenella clymene specimen. There was no evidence of boat strike or interaction with fishing gear. Although the organs were highly parasitized, this was not the cause of the death. Alterations in the lungs suggested infectious interstitial pneumonia. Currently, this species is classified as ‘Least concern’ by the IUCN and is not listed on the Brazilian Official National List of Species Threatened with Extinction. Hence, our study highlights the importance of a systematic monitoring of marine mammals, stranding networks and databases for species conservation. We also point out the need for an official list of endangered species of the Pernambuco state, to support local and regional actions. Thus, national conservation plans could be achieved in a more straightforward way and, in the best possible way,strategic priorities for species conservation, protection, and management could be developed and applied.

Eye morphology of Guiana dolphins (Sotalia guianensis) and Clymene dolphins (Stenella clymene)

Recent studies showed that vision and hearing in dolphins are mechanisms for perception of the environment, and transmission of information among individuals. Considering that Guiana dolphins (Sotalia guianensis) are distributed in costal regions, and Clymene dolphins (Stenella clymene) are found in oceanic environments, the objective of this study was to compare the morphology of the eyes of these two species, assessing the differences in eye structures in both environments. Five specimens of Sotalia guianensis and four specimens of Stenella clymene were analyzed. All the specimens were found stranded in the northeastern coast of Brazil. Samples were fixated in 10% formaldehyde, dissected, photographed, processed, and analyzed by optical microscopy. The inferior palpebral region of the two species showed a granular layer, subcutaneous lymphoid tissue, and innervation. Morphometric values of the eyelid structures and eye bulb were greater in S. clymene. The cornea showed four layers in S. clymene: anterior epithelium, anterior lamina, stroma, and posterior lamina. The sclera of S. guianensis showed more melanocytes and presence of mechanoreceptors next to the Harderian gland. It is possible to suggest that the geographical distribution of these cetaceans determine their eye morphology, which is an adaptation to the intrinsic characteristics of the aquatic environment.

A Visitor of Tropical Waters: First Record of a Clymene Dolphin (Stenella clymene) Off the Patagonian Coast of Argentina, With Comments on Diet and Metazoan Parasites

The poorly known Clymene dolphin (Stenella clymene) is a small oceanic cetacean distributed in tropical and subtropical waters of the Atlantic Ocean. In this study, we report, for the first time, a vagrant individual of Clymene dolphin in Argentina (Rada Tilly) that represents the current southern-most record for this cetacean species. We provide a molecular identification of the dolphin, based on partial sequences of the mitochondrial cytochrome b gene, generated from DNA extracted from its metazoan parasites. Three prey species, namely Argentine hake, Patagonian squid and lobster krill were identified from hard pieces collected in the stomach. Seven metazoan parasite taxa (three in adult stage, one immature stage and three in larval stage) were identified using morphological and molecular data, i.e., the digenean Pholeter gastrophilus (new host record), the cestodes Tetrabothrius (Tetrabothrius) forsteri, Clistobothrium grimaldii unidentified phyllobothriid plerocercoids, the nematodes Anisakis pegreffii (new host record), Halocercus delphini and the acanthocephalan Corynosoma australe (new host record). Our study provides the first molecular exploration of the metazoan parasite diversity in delphinids from the southwestern Atlantic, and contributes significantly to understand the poorly known parasite fauna of the Clymene dolphin.

Morphological description of the male reproductive tract of the Clymene dolphin (Stenella clymene, Gray, 1850)

AbstractStenella clymene is an endemic species of dolphin living in tropical regions in the Atlantic Ocean. Despite its wide distribution, there is still scarce information on Stenella clymene, including its reproductive biology. In this context, this work describes the morphology of the whole male reproductive tract of the Clymene dolphin. Five males (N = 5) were studied after stranding on the northeast coast of Brazil. The analysis was performed through the use of macroscopic techniques and light and scanning microscopy. The male reproductive system consists of large testes wrapped around the tunica albuginea and adhered to the epididymis; the testes are attached to the abdominal cavity by the mesorchium. The ductus deferens is convoluted in the proximal portion and rectilinear in the distal portion. The prostate was the only accessory gland found, which is submerged by the prostate compressor muscle and lined with a dense fibroelastic capsule. The penis is classified as fibroelastic, with a spiral sigmoid flexure associated with a large volume of muscle tissue. The penis is inserted into two vestigial bones or pelvic bones, which exhibit no connection with the spine. In conclusion, the macro‐ and microscopic conformation and other morphofunctional features of the male reproductive organs of Stenella clymene are in accord with the anatomy observed in other Cetartiodactyla.

First record of Clymene dolphin (Stenella clymene Gray, 1846) in European waters

First record of Clymene dolphin (Stenella clymene Gray, 1846) in European waters

Molecular, serological, pathological, immunohistochemical and microbiological investigation of Brucella spp. in marine mammals of Brazil reveals new cetacean hosts.

Brucella-exposure and infection is increasingly recognized in marine mammals worldwide. To better understand the epidemiology and health impacts of Brucella spp. in marine mammals of Brazil, molecular (conventional PCR and/or real-time PCR), serological (Rose Bengal Test [RBT], Competitive [c]ELISA, Serum Agglutination Test [SAT]), pathological, immunohistochemical (IHC) and/or microbiological investigations were conducted in samples of 129 stranded or by-caught marine mammals (orders Cetartiodactyla [n=124], Carnivora [n=4] and Sirenia [n=1]). Previous serological tests performed on available sera of 27 of the 129 animals (26 cetaceans and one manatee), indicated 10 seropositive cetaceans. Conventional PCR and/or real-time PCR performed in cases with available organs (n=119) and/or blood or swabs (n=10) revealed 4/129 (3.1%) Brucella-infected cetaceans (one of them with positive serology; the remaining three with no available sera). Pathological, IHC and/or microbiological analyses conducted in PCR/real-time PCR and/or seropositive cases (n=13) revealed Brucella-type lesions, including meningitis/meningoencephalitis, pneumonia, necrotizing hepatitis, pericarditis and osteoarthritis in some of those animals, and positive IHC was found in all of them (excepting two live-stranded animals without available organs). Brucella spp. culture attempts were unsuccessful. Our results demonstrated exposure, asymptomatic, acute and chronic Brucella sp. infection in several cetacean species in the Brazilian coast, highlighting the role of this pathogen in stranding and/or death, particularly in Clymene dolphin (Stenella clymene) and short-finned pilot whale (Globicephala macrorhynchus) off Ceará State. Novel hosts susceptible to Brucella included the franciscana (Pontoporia blainvillei), the Guiana dolphin (Sotalia guianensis) and the spinner dolphin (Stenella longirostris). Additionally, three coinfection cases involving Brucella spp. and cetacean morbillivirus, Edwarsiella tarda and Proteus mirabilis were detected. To the best of our knowledge, this is the first long-term and large-scale survey of Brucella spp. in marine mammals of South America, widening the spectrum of susceptible hosts and geographical distribution range of this agent with zoonotic potential.

Stomach Content Analysis and Concentrations of Chemical Pollutants in the Clymene Dolphin (Stenella Clymene, Gray 1846) from the Coastal Waters of Ghana

Stomach content analysis constitutes an important component of fisheries management, providing insight into fish feeding patterns and quantitative assessment of food habits. Thus, a study aimed at obtaining dietary information from stomach contents analysis of the most common by-caught dolphin species, Stenella clymene, beached from the coastal waters of Ghana, along the Gulf of Guinea was undertaken. The stomachs of 39 by-caught clymene dolphins landed at three fisheries landing beaches along the Ghanaian coast, were analyzed. A further study correlating the chemical contaminant load in tissues of Clymene dolphins to that of their preferred prey was undertaken. The stomach contents were generally composed of digested items. Fish, cephalopods and crustaceans were identified and represented a diversity of 12 species. On taxa level, fish was the most frequent (69%) and numerically the most important prey (46.57) followed by cephalopods (3.05) with crustaceans being present in trace amounts (1.55). However, both cephalopods and fish represented a more balanced share of the diet in biomass (45% and 51%) respectively. Thus, clymene dolphins off the coastal waters of Ghana appear to rely principally on both fish and cephalopods for food. Parasites also dominated the gut contents in relative abundance (48.83%). Prey items accumulated chemical contaminants at relatively the same concentrations (50%) as the blubber, liver and muscle of the clymene dolphins, confirming that food is the main source of exposure to contaminant load for marine mammals. With regards to quantitative analysis of prey species of cetaceans, this study of diet in clymene dolphins is the first recorded in this area.

Survey of Brucella spp. and Leptospira spp. antibodies in cetaceans and manatees of the Amazon basin and Atlantic Ocean, Brazil

Aquatic mammals can act as sentinels of emerging and resurging pathogens in the environment. Brucella spp. and Leptospira spp. are 2 zoonotic pathogens relevant to aquatic mammals, and their detection can be used to assess pathogen exposure. In this study, serum from 84 individuals-63 cetaceans (families Iniidae, n = 37; Delphinidae, n = 22; and Kogiidae, n = 4) and 21 West Indian manatees Trichechus manatus-was tested by the Rose Bengal Test (RBT) and a commercial competitive enzyme-linked immunosorbent assay (c-ELISA) for detecting Brucella spp. antibodies, and the microscopic agglutination test (MAT) for screening Leptospira spp. exposure. Overall, 4.8% (3/63) of cetaceans were positive by RBT and 15.9% (10/63) by c-ELISA for Brucella spp. Serum from 8 c-ELISA positive cetaceans (with available serum) was further tested via serum agglutination test (SAT) and 1 individual was positive. c-ELISA was more sensitive than RBT. Exposure to Brucella spp. was found in 5 cetacean species: Clymene dolphin Stenella clymene, short-finned pilot whale Globicephala macrorhynchus, pygmy killer whale Feresa attenuata, melon-headed whale Peponocephala electra and Atlantic bottlenose dolphin Tursiops truncatus in the Atlantic Ocean, Brazil, expanding the range of known Brucella seropositive aquatic hosts. No evidence of Brucella spp. exposure was found in Iniidae and Kogiidae odontocetes and manatees. Antibodies against Leptospira spp. were not detected in cetaceans and sirenians by MAT. These results contribute to the evaluation of different Brucella spp. serological methods in cetaceans and manatees and highlight the epidemiology of zoonotic pathogens in aquatic mammals of the southwestern Atlantic Ocean and the Amazon basin.

Clymene dolphin (Stenella clymene) whistles in the Southwest Atlantic Ocean

The Clymene dolphin despite being endemic for the Atlantic Ocean continues to be the least known species in the genus Stenella without available information on their vocal repertoire in Brazilian waters. Data were obtained during mitigation and monitoring work required by IBAMA under the federal environmental licensing as conditions of the license 108/16 for the 3D seismic survey in Para/Maranhao Sedimentary Basin process 02022.000015/2014. The species record was performed onboard the vessel Polarcus Alima with a Mseis (Night Hawk III) four-element towed array passing signals to a digital M-Audio, recording at 96 kHz/16bits. During visual and acoustic monitoring with the air-guns off, a group of approximate 80 dolphins were sighted and recorded on May 8th, 2016 (00˚38’00” N, 44˚45’25” O) at 3,425 m depth. The wav-files were analyzed through the spectrogram configured as DFT 2048 samples, 70% overlap and Hamming window of 1024 points generated by software Raven Pro 1.5. The results of 14 min recording allowed the extraction of 257 whistles. Minimum frequencies ranged from 5.20 kHz to 15.92 kHz (mean = 10.99 kHz); maximum frequencies ranged from 7.72 kHz to 28.04 kHz (mean = 16.16 kHz); whistle duration ranged from 0.01 s to 1.52 s (mean = 0.43 s). These results are important since they represent the first acoustic record of Clymene dolphins in Brazil.

RETROSPECTIVE SURVEY FOR PATHOGENS IN STRANDED MARINE MAMMALS IN NORTHEASTERN BRAZIL: BRUCELLA SPP. INFECTION IN A CLYMENE DOLPHIN ( STENELLA CLYMENE).

: We surveyed 13 carcasses of marine mammals (12 Trichechus manatus and one Stenella clymene) that had stranded in northeastern Brazil during 1990-2013 for infectious diseases by screening tissues from the collection of the Brazilian National Center of Research and Conservation of Aquatic Mammal, Chico Mendes Institute for Biodiversity Conservation. Brucella spp. and Mycobacterium spp. were investigated by culturing and PCR of tissue samples, whereas Sarcocystidae parasites, Leptospira spp., and Morbillivirus were surveyed for using specific PCR assays. Brucella spp. and Mycobacterium spp. were not isolated through microbiologic culturing, and all animals were negative for detection of Sarcocystidae parasites, Leptospira spp., Mycobacterium spp., and Morbillivirus by PCR assays. All manatees were negative for Brucella spp. infection, but Brucella ceti was detected in the brain tissue of an S. clymene calf by using a PCR assay.

An Initial Population Structure and Genetic Diversity Analysis for Stenella clymene (Gray, 1850): Evidence of Differentiation Between the North and South Atlantic Ocean

An Initial Population Structure and Genetic Diversity Analysis for Stenella clymene (Gray, 1850): Evidence of Differentiation Between the North and South Atlantic Ocean

Updates on Cyamidae (Crustacea: Amphipoda): redescriptions of Cyamus monodontis Lütken, 1870 and Cyamus nodosus Lütken, 1861, a new species of Isocyamus, and new host records for Syncyamus ilheusensis Haney, De Almeida and Reis, 2004

ABSTRACTSpecimens of cyamids were collected from fresh cetacean carcasses from Brazil, Iceland and New Caledonia. Identifications were based on literature and comparative material. Redescriptions based on the type series of Cyamus monodontis and Cyamus nodosus collected from narwhal Monodon monoceros are proposed, and lectotypes and paralectotypes are designated. A new species of Isocyamus was described herein, Isocyamus indopacetus sp. nov., which is characterised by the maxilliped with outer plate and two spine-like processes on the bases of gills. This is the first record of a cyamid parasitising the Longman’s beaked whale (Indopacetus pacificus) from New Caledonia. An updated key to Isocyamus is presented herein. Syncyamus ilheusensis is registered for the first time for the melon-headed whale Peponocephala electra and from the Clymene’s dolphin Stenella clymene from Ceará, Brazil.www.zoobank.org/urn:lsid:zoobank.org:pub:451A4857-9CFC-4C81-AF70-8DFD0D7CEB16

Ecological niche modeling of Stenella dolphins (Cetartiodactyla: Delphinidae) in the southwestern Atlantic Ocean

Since the Moreno's et al. (2005) work, no study was done to update the distribution patterns of Stenella dolphins in the southwestern Atlantic Ocean. Ecological niche modeling was used to redefine the distribution patterns of Stenella dolphins in this area of Atlantic Ocean. Maximum entropy method (Maxent) was employed to generate models using a set of environmental variables as explanatory variables of the location records obtained by sighting and accidental captures. All ecological niche models performed returned AUC values >0.9. Areas with high environmental suitability for pantropical spotted dolphin (Stenella attenuata), Clymene dolphin (Stenella clymene) and spinner dolphins (Stenella longirostris) are found in warm (>25°C) and deep waters (≥1000m). High environmental suitability for Atlantic spotted dolphin (Stenella frontalis) seems to occur between 20.5°S and 30°S in the southeastern Brazilian coastal waters. The projected maps of species distributions showed patterns closely related to environmental changes at a fine spatial scale and added valuable information about the offshore limits of those oceanic species. The results suggest that the different species of Stenella have distinct environmental requirements in the southwestern Atlantic Ocean.

Clymene dolphins (Stenella clymene) in the eastern tropical Atlantic: distribution, group size, and pigmentation pattern

The Clymene dolphin (Stenella clymene) is endemic to warm Atlantic Ocean waters and is one of the least known delphinids. We reviewed existing published data (primarily strandings, captures, and bycatch) and unpublished sightings to examine the distribution, habitat, group size, seasonality, and pigmentation patterns of Clymene dolphins within the eastern tropical Atlantic (ETA). Following photographic verification, 84 confirmed and 8 probable at-sea sightings of ETA Clymene dolphins were analyzed. The documented records ranged from ∼19°N in central Mauritania to 14°26′S in southern Angola, confirming 14 ETA range states. At-sea sightings occurred in water depths of 437–5,000 m and at distances from shore of 21–937 km, corresponding with a continental slope and oceanic habitat. Sightings within the wider ETA region had year-round occurrence. Group size ranged from 3–1,000 animals, with 60.9% of groups comprising ≤ 50 animals. Photographic examination revealed a complex and variable pigmentation pattern in ETA Clymene dolphins, which contrasts with the simple tripartite pattern often described for this species. In particular, most ETA animals had a dark gray lateral stripe extending diagonally along the flank from the beak to the genital area and a conspicuous dark gray eye–flipper stripe of varying intensity and thickness. The at-sea sightings documented here significantly extend current knowledge of the distribution, ecology, and appearance of the Clymene dolphin.

Lesions associated with Halocercus brasiliensis Lins de Almeida, 1933 in the lungs of dolphins stranded in the Northeast of Brazil.

The parasitic fauna of cetaceans is an important tool for ecological studies, including analyses on the causes of death. Halocercus brasiliensis is a nematode frequently found in the bronchi and bronchioles of some cetaceans, and it is commonly associated with focal inflammation of the respiratory tract leading to bacterial pneumonia and septicemia and, sometimes, to death. The objective of this study was to report infections by H. brasiliensis in the respiratory tract of Delphinidae stranded on the northern seaside of Bahia, Sergipe, and south of Alagoas, all states in the northeast region of Brazil. A total of 30 individuals, 1 Feresa attenuate (pygmy killer whale), 9 Stenella clymene (Clymene dolphin), and 20 Sotalia guianensis (Guiana dolphin) were studied. In 16 of them, the presence of H. brasiliensis was observed with a mean intensity of 3.5 ± 0.6 (range 1-9) in the hosts. Macroscopically, parasitic calcified nodules, lung congestion, edema, and emphysema were observed. Histopathological examination showed interstitial and granulomatous pneumonia with multifocal infiltrates, discrete to moderate edema, congestion, diffuse hemorrhage, and foci of calcification. We conclude that parasitic pneumonia in the sampled individuals may have directly contributed to stranding and death of the animals.