Lack Of Pigmentation Research Articles

Squamous Cell Carcinoma in a Pig

Background: Squamous cell carcinoma (SCC) is a malignant neoplasm of epidermal cells that exhibits keratinocyte differentiation. These neoplasms are common in dogs, cats, horses, and cattle, relatively uncommon in sheep, and rarely affect goats and pigs. There are several factors that are associated with the development of SCC, including prolonged exposure to ultraviolet light, lack of pigment in the epidermis, and sparse coating or lack of fur at the affected sites. The aim of this study was to report the occurrence of squamous cell carcinoma in a domestic pig.Case: A surgically removed nodule from the left ear of a female, light-colored, three-year-old pig, which breed was not defined, was submitted for histopathological analysis. The sample was fixed in 10% formalin, analyzed macroscopically, routinely processed for histology, sectioned at five microns and stained with hematoxylin and eosin. Additionally, anticytokeratin (AE1/AE3) and anti-vimentin immunohistochemical assays were performed. All additional information was provided by the animal’s owner. According to the history obtained, the animal belonged to a herd made up of five females and one boar. For four months, multiple nodules started to grow on the outer surface of the pig’s ear and in many occasions exhibited ulceration and bleeding. One of the nodules was submitted for histopathology examination. Macroscopically it measured 3 cm in diameter, had an irregular and ulcerated surface, and a wide base. Cut surface had a firm consistency and whitish color. Microscopic examination revealed proliferation of neoplastic epithelial cells arranged in islands and trabeculae, with slightly eosinophilic cytoplasm, pleomorphic, round, reniform nucleus, with loose chromatin and 1-3 nucleolus. Mitotic figures were infrequent. In the central area of the islands, there was individual cell keratinization. There was a moderate, fibrovascular supporting stroma with intense inflammatory infiltrate composed of lymphocytes, plasma cells and eosinophils. Anti-cytokeratin (AE1/AE3) immunohistochemical assay (IHC) revealed a strong diffuse positive staining on the cytoplasm of tumoral epithelial cells, and anti-vimentin IHC showed positive staining on the supporting tissue cells (fibroblasts and endothelial cells).Discussion: The diagnosis of squamous cell carcinoma in this pig was based on clinical and pathological findings since it was observed proliferation of neoplastic epithelial cells often forming “keratin pearls” and immunohistochemistry positive for cytokeratin was immunostaining in the cytoplasm of tumor cells. Information on the occurrence of SCC in pigs is scarce in the literature, especially in Brazil. In a survey of neoplasms in farm animals in Southern Rio Grande do Sul with cases from 1978 to 2002, neoplasms in pigs represented 0.6% of the diagnoses when compared to the number of neoplasms in cattle and horses. The low number of cases in this species is due to the fact that a large proportion of the population is slaughtered at a young age and therefore the chances to develop neoplasms are lower. The main SCC growth sites include areas deprived of hair, especially in animals with unpigmented skin. In the pig described here, the neoplasm was located on the outer surface of the ear, which was exposed to ultraviolet rays. Granuloma, papilloma, and basal cell tumor should be considered in the list of differential diagnosis when SCC is suspected. Neoplasms in pigs are scarcely reported.Keywords: neoplasm, carcinoma, pig, immunohistochemical.

Short-term exposure to low doses of rotenone induces developmental, biochemical, behavioral, and histological changes in fish.

Rotenone, a natural compound derived from plants of the genera Derris and Lonchocarpus, is used worldwide as a pesticide and piscicide. This study aims to assess short-term toxicity of rotenone to early-life stages of the fish Danio rerio and Poecilia reticulata using a wide and integrative range of biomarkers (developmental, biochemical, behavioral, and histopathological). Moreover, the species sensitivity distribution (SSD) approach was used to compare rotenone acute toxicity to fish species. Toxicity tests were based on the OECD protocols, fish embryo toxicity test (for D. rerio embryos), and fish acute toxicity test (for P. reticulata juveniles). D. rerio embryos were used to estimate lethal concentrations and analyze embryonic and enzymatic alterations (activity of catalase, glutathione-S-transferase, and cholinesterase), while P. reticulata juveniles were used for the assessment of histological damage in the gills and liver. Rotenone induced significant mortality in zebrafish embryos with a 96-h lethal concentration 50% (LC50) = 12.2 μg/L. Rotenone was embryotoxic, affecting the development of D. rerio embryos, which showed cardiac edema; tail deformities; loss of equilibrium; and a general delay characterized by lack of tail detachment, delayed somite formation, yolk sac absorption, and lack of pigmentation. Biochemical biomarker inhibition was observed for concentrations ≥1 μg/L for CAT and glutathione-S-transferase (GST) and for cholinesterase (ChE) in concentration from 10 μg/L. Behavioral changes were observed for P. reticulata juveniles exposed to concentrations equal to or above 25 μg/L of rotenone; moreover, histological damage in the liver and gills of fish exposed to concentrations equal to or above 2.5 μg/L could be observed. A hazard concentration 5% (HC5) of 3.2 μg/L was estimated considering the acute toxicity data for different fish species (n = 49). Lethal and sublethal effects of rotenone raise a concern about its effects on nontarget fish species, especially because rotenone and its metabolite rotenolone are frequently reported in the microgram range in natural environments for several days after field applications. Rotenone should be used with caution. Given the high toxicity and wide range of sublethal effects here reported, further studies in a chronic exposure scenario are recommended.

Examining KIT, EDNRB, MITF, PMEL17, MLANA Genes to Determine the Genetic Basis of Equine Deafness

There appears to be a correlation between congenital deafness and lack of pigmentation in a small pedigree of Spanish Mustangs. At this time, no hereditary explanation has been presented for this pattern as it appears in horses. Based on the previously determined correlation of melanocyte function and/or migration to deafness in humans, we have conducted a candidate gene study to attempt to link the white coat pigmentation, blue eyes and cochleosaccular deafness within this pedigree. Candidate genes were chosen on the basis of correlation to similar disease states in humans, dogs and cats, including KIT, EDNRB, MITF, and MLANA. KIT, a receptor tyrosine kinase in the pigment production pathway, has been implicated in multiple mammalian deafness studies to date. A mutation (KI16 + 1037A) in the 5′ splice junction of exon 17 is known to cause sabino coloration, but was determined to not be linked to deafness. Alternatively, a heterozygous glycine to serine non‐synonymous mutation was identified within exon 6 of MITF, a transcription factor necessary for proper melanocyte differentiation, but doesn't appear to correlate to deafness. In addition, no mutations within exons were found in neither EDNRB (endothelin receptor type B) nor MLANA, also known as melan A or MART1 (melanoma antigen recognized by t‐cells). Further analysis of additional candidate genes, including PMEL17 and SOX10, and the inclusion of intronic sequence analysis for all candidate genes, will be necessary to determine the cause of cochleosaccular deafness, through mutations in these genes or others.

Taiwanassiminea phantasma n. sp.: a terrestrial assimineid (Caenogastropoda: Truncatelloidea) from Middle Osborn Island, Kimberley, Western Australia

A new terrestrial assimineid gastropod, Taiwanassiminea phantasma n. sp. (Truncatelloidea: Assimineidae), is described. Taiwanassiminea phantasma is characterised by its translucent, conical shell with deeply impressed sutures, spiral groove surrounding a wide umbilicus, relative lack of pigmentation and long distal penial papilla. The species differs from most assimineids in having a subcircular aperture and an operculum with a central nucleus. Taiwanassiminea phantasma has anatomical similarities to other members of Taiwanassiminea, and this relationship is supported by a partial cytochrome oxidase I mitochondrial analysis. Taiwanassiminea phantasma lives in leaf litter in vine thickets on Middle Osborn Island in northern Kimberley, Western Australia, where it is possibly endemic. No terrestrial assimineid is otherwise known from mainland Australia or its adjacent islands, including Tasmania.http://zoobank.org/urn:lsid:zoobank.org:pub:A14ACAAE-4BAD-402D-9F9D-3BC9D928411A

Dermoscopy in cutaneous melanoma

Abstract Background The mortality of cutaneous melanoma has not declined over the past 50 years. The only interventions that can reduce mortality are primary prevention and early diagnosis, and the dermoscopic evaluation is essential to achieve this. Dermoscopy identifies characteristics of melanoma that would go unnoticed to the naked eye. The aim of this paper is to report the most frequent dermoscopic findings in patients diagnosed with in situ and invasive melanoma. Material and methods An observational and retrospective study of contact dermoscopy was performed using LED Dermlite™ and camera Dermlite™ dermoscope. The findings evaluated were: asymmetry in two axes, association of colours, lack of pigment, irregular points, atypical network, pseudopods, blue veil, ulceration, and peri-lesional pink ring. These dermoscopic findings were compared with the histological diagnosis. Results The study included 65 patients with cutaneous melanoma; 10 in situ , and 55 invasive. The mean Breslow in invasive melanoma was 3 mm. Most patients (35) had localisation in extremities. In all patients, the most frequent dermoscopic finding was asymmetry in two axes, followed by association of two or more colours; in melanoma in situ , asymmetry was the most frequent, followed by atypical-irregular points. In invasive melanoma asymmetry in two axes, the association of two or more colours, and pseudopods, were the most frequent findings. Conclusion Asymmetry in two axes is the most common dermoscopic finding in in situ and invasive melanoma. The presence of two or more colours in a pigmented lesion should be suspected in an invasive melanoma.

Dermatoscopia en melanoma cutáneo

BackgroundThe mortality of cutaneous melanoma has not declined over the past 50 years. The only interventions that can reduce mortality are primary prevention and early diagnosis, and the dermoscopic evaluation is essential to achieve this. Dermoscopy identifies characteristics of melanoma that would go unnoticed to the naked eye.The aim of this paper is to report the most frequent dermoscopic findings in patients diagnosed with in situ and invasive melanoma. Material and methodsAn observational and retrospective study of contact dermoscopy was performed using LED DermliteTM and camera DermliteTM dermoscope. The findings evaluated were: asymmetry in two axes, association of colours, lack of pigment, irregular points, atypical network, pseudopods, blue veil, ulceration, and peri-lesional pink ring. These dermoscopic findings were compared with the histological diagnosis. ResultsThe study included 65 patients with cutaneous melanoma; 10 in situ, and 55 invasive. The mean Breslow in invasive melanoma was 3 mm. Most patients (35) had localization in extremities. In all patients, the most frequent dermoscopic finding was asymmetry in two axes, followed by association of two or more colours; in melanoma in situ, asymmetry was the most frequent, followed by atypical-irregular points. In invasive melanoma asymmetry in two axes, the association of two or more colours, and pseudopods, were the most frequent findings. ConclusionAsymmetry in two axes is the most common dermoscopic finding in in situ and invasive melanoma. The presence of two or more colours in a pigmented lesion should be suspected in an invasive melanoma.

First record of albinism in salema, Sarpa salpa (Perciformes: Sparidae), in the Mediterranean Sea

The first record of albinism in salema (Sarpa salpa(Linnaeus, 1758)) observed in Cabo de Palos, Western Mediterranean, is reported here. The adult specimen showed an overall lack of pigmentation, presented normally coloured eyes and a further local dyspigmentation, being, therefore, classifiable as a partial albino. No noticeable changes in size nor morphology were detected.

First record of albinism in the brown sea cucumber Isostichopus fuscus in the Gulf of California, Mexico

Albinism is a hereditary lack of pigmentation caused by deficiencies in enzymes related to the metabolism of melanin. This mutation is present in marine vertebrates and invertebrates, including the Holothuroidea class; nevertheless, information about the occurrence of albinism in these kinds of echinoderms is scarce and refers to species from temperate and cold regions of the ocean. In 2013, we observed two albino individuals of Isostichopus fuscus , one at Loreto (25°45′54″N, 111°14′36″W) and the second one at Los Angeles Bay (29°02′54″N, 113°29′49″W). This is the first documented record of albinism for this species.

The relationship of melanocytic differentiation with prognostic markers in medullary thyroid carcinomas

IntroductionMedullary thyroid carcinoma (MTC) makes up 5–10% of thyroid malignancies. Small cell, squamous, giant cell or melanocytic differentiation can rarely be seen in MTCs. It is important to determine those with the potential to act aggressively such as cases with melanocytic differentiation at the time of diagnosis. Materials and methodA total of 46 MTC cases diagnosed at four different centers between 2002 and 2013 were included in the study. Immunohistochemical (IHC) staining with Melan-A and HMB-45 was performed in all cases. ResultsSix of the 46 MTC cases were medullary microcarcinomas and three were multicentric medullary carcinomas. There were 34 females and 12 males with a mean age at onset of 51.4 years and mean tumor diameter of 23.2mm. Lymph node metastasis (LNM) was found in 13 of the 38 cases that had data regarding the lymph nodes. Immunohistochemically, Melan A staining was seen in four cases. HMB45 staining was seen in four cases. A statistically significant relationship was found between LNM and diameter, Melan A expression (p=0.02, p=0.03 respectively) but there was no significant relationship with HMB45 expression (p=0.07). General survival data were present for 35 of the 46 cases. All cases without lymph node metastasis survived (21/21) while 8 of 11 cases with lymph node metastasis survived among cases with survival data; one case that was diffuse-strong positive for both HMB45 and Melan A was lost due to distant organ metastasis six months after the diagnosis. DiscussionShould the possibility of melanocytic differentiation be evaluated in cases where melanocytic differentiation is not reflected in the morphology (lack of pigment) in MTCs? We did not come across a study on the subject in the English literature. The effect of melanocytic differentiation on the prognosis in MTCs should be investigated in larger series.

Aspergillus Niger Infection Associated with Systemic Oxalosis: An Autopsy Diagnosis Without Culture

This case report presents a 60-year-old male with a past medical history that included diabetes mellitus type II, chronic alcoholism, Hepatitis C infection, and presumptive pneumonia who died following a cholecystectomy. At autopsy, in addition to sequelae of the alcohol use (e.g., cirrhosis, splenomegaly, and esophageal varices), two contiguous black discolorations in the right lung composed of friable material and identified as fungal hyphae were found. Associated with the fungal hyphae was oxalic acid deposition. Oxalate crystals were also identified in the kidney of the decedent. Although no fruiting bodies were identified and no cultures were performed, a diagnosis of Aspergillus niger was made based upon the grossly apparent pigment production, lack of pigment within the fungal hyphae, and the oxalic acid production. Systemic oxalosis can occur as a result of an Aspergillus niger infection, and, its presence in the kidney would explain the decedent's worsening renal function prior to death.

Rhodoferax saidenbachensis sp. nov., a psychrotolerant, very slowly growing bacterium within the family Comamonadaceae, proposal of appropriate taxonomic position of Albidiferax ferrireducens strain T118T in the genus Rhodoferax and emended description of the genus Rhodoferax

A Gram-stain-negative, oxidase and phosphatase-positive and catalase-negative, short rod-shaped bacterium was isolated from sediment of a drinking water reservoir in Germany. Based on 16S rRNA gene sequence and phenotypic properties, the bacterium belongs to the genus Rhodoferax within the family Comamonadaceae. The new taxon differed from related species mainly with respect to its fatty acid composition, low growth temperature, lack of pigments in young cultures and ability to utilize glycerol and d-mannose but not urea. The major fatty acids were C16 : 1ω7c and/or iso-C15 : 0 2-OH, C16 : 0, and C18 : 1ω7c. The only ubiquinone detected was ubiquinone Q-8. The DNA G+C content was 60.3-61 mol%. Because of the phenotypic and genotypic differences from the most closely related taxa, the new strain represents a novel species for which the name Rhodoferax saidenbachensis sp. nov. is proposed. The type strain is ED16(T) ( = CCUG 57711(T) = ATCC BAA-1852(T) = DSM 22694(T)). An emended description of the genus Rhodoferax is proposed. Based on the results of this study, strain T118(T) (Albidiferax ferrireducens) is properly placed in the genus Rhodoferax as Rhodoferax ferrireducens.

Report of an Albino Red Squirrel from Sainte-Luce, Quebec, Canada

We report the observation of an albino male Tamiasciurus hudsonicus (Red Squirrel) from Sainte-Luce in eastern Quebec, Canada. While occurrences of entirely albino individuals have been sporadically reported in the wild in other sciurid species, true albinism is rare in T. hudsonicus. That albino sciurids can survive in the wild may be related to their relatively minor visual deficits compared to other albino mammals, which experience a greater loss of vision. The lack of pigmentation, however, may be a major disadvantage in the wild for the Red Squirrel, which is a diurnal and arboreal prey species. In conjunction with the recessive nature of albinism, it is not surprising that albino individuals are rarely reported for this species.

Sulf1 modulates BMP signaling and is required for somite morphogenesis and development of the horizontal myoseptum

Heparan sulfate proteoglycans (HSPGs) are glycosylated extracellular or membrane-associated proteins. Their unbranched heparan sulfate (HS) disaccharide chains interact with many growth factors and receptors, modifying their activity or diffusion. The pattern of HS sulfation can be altered by the enzymes Sulf1 and Sulf2, secreted extracellular 6-O endosulfatases, which remove specific sulfate groups from HS. Modification by Sulf enzymes changes the binding affinity of HS for protein such as ligands and receptors, affecting growth factor gradients and activities. The precise expression of these sulfatases are thought to be necessary for normal development. We have examined the role of the sulf1 gene in trunk development of zebrafish embryos. sulf1 is expressed in the developing trunk musculature and as well as in midline structures such as the notochord, floorplate and hypochord. Knockdown of sulf1 with antisense morpholinos results in poor differentiation of the somitic trunk muscle, loss of the horizontal myoseptum, lack of pigmentation along the mediolateral stripe, and improper migration of the lateral line primordium. sulf1 knockdown results in a decrease in the number of Pax7-expressing dermomyotome cells, particularly along the midline where the horizontal myoseptum develops. It also leads to decreased sdf1/cxcl12 expression along the mediolateral trunk musculature. Both the Pax7 and cxcl12 expression can be restored by inhibition pharmacological inhibition of BMP signaling, which also restores formation of the myoseptum, fast muscle development, and pigmentation patterning. Lateral line migration and neuromast deposition depend on sdf1/cxcl12 and FGF signaling respectively, both of which are disrupted in sulf1 morphants. Pharmacological activation of FGF signaling can rescue the spacing of neuromast deposition in these fish. Together this data indicate that sulf1 plays a crucial role in modulating both BMP and FGF signaling along the developing myoseptum to coordinate the morphogenesis of trunk musculature, associated pigment cells, and lateral line neuromasts.

Amelanotic Melanoma Masquerading as a Granular Cell Lesion

Amelanotic melanoma (AM) presents a diagnostic challenge due to its wide clinical presentations, lack of pigmentation, and varied histological appearances. Immunohistochemistry plays a crucial role in the diagnosis of these lesions. Amelanotic melanoma of oral mucosa is an uncommon lesion. We report a case of a 50-year-old male patient with a growth on the anterior mandibular gingiva of seven-month duration. In the present case, histologically, the tumour resembled a granular cell lesion, which has not been reported previously in AM. Diagnosis was possible by a sequential panel of immunohistochemical markers, of which finally vimentin, S100, HMB45, and Melan-A were positive. The tumor was surgically excised, and postsurgical radiotherapy was given.

Frequency of virus in some Diplodia pinea and Gremmeniella abietina isolates originated from Turkey

Diplodia pinea and Gremmeniella abietina are common pathogens causing shoot blight and dieback of pine all over the world. D. pinea is one of the main causal agents of shoot blight of Calabrian pines in the Mediterranean countries including Turkey. G. abietina has been recently observed on saplings and seedlings of Pinus nigra, which remain under snow cover during winter dormancy in Dedegul Mountain in the Mediterranean Region of Turkey. The presence of viruses in fungi has been known for many years. An accumulating number of cloned and sequenced viral genomes have enabled us to detect virus in increasing number of fungal species in the recent years. D. pinea and G. abietina are known to contain members of the virus families Narnaviridae, Totiviridae and Partitiviridae, which can infect single fungal isolates. Viral dispersal in fungi mainly occurs via anastomosis. Some Diplodia and G. abietina isolates have different characteristics, such as reduced virulence and growth rate, lack of pigmentation, altered colony morphology, and reduction in conidial production due to presence of viral particles. In this study, 18 D. pinea and 6 G. abietina isolates were investigated for the presence of dsRNA. Double-stranded RNA was isolated using a commercial RNA extraction kit and visualized in agarose gel electrophoresis. Isolates containing dsRNA were also investigated for their in vitro growth rate and ability to produce conidia. Three (50%) G. abietina and ten (56%) D. pinea isolates contained dsRNA that had an approximate molecular size of 1.6 kb. Key words: Scleroderris canker, calabrian pine, dsRNA.

Genetic differentiation between cave and surface-dwelling populations of Garra barreimiae (Cyprinidae) in Oman

BackgroundPhenotypic similarities among cave-dwelling animals displaying troglomorphic characters (e.g. reduced eyes and lack of pigmentation) have induced a long-term discussion about the forces driving convergent evolution. Here we introduce Garra barreimiae Fowler & Steinitz, 1956, as an interesting system to study the evolution of troglomorphic characters. The only hitherto known troglomorphic population of this species lives in Al Hoota Cave (Sultanate of Oman) close to a surface population. As a first approach, we assessed the genetic differentiation between the two morphotypes of G. barreimiae to determine whether gene flow still occurs.ResultsWe analysed the mitochondrial control region (CR). In G. barreimiae the CR starts immediately downstream of the tRNA-Thr gene, while the tRNA-Pro gene is missing at this genomic location. Interestingly, a putative tRNA-Pro sequence is found within the CR. The phylogenetic analyses of the CR sequences yielded a tree divided into three clades: Clade 1 has a high genetic distance to the other clades and contains the individuals of three populations which are separated by a watershed from all the others. Clade 2 comprises the individuals from Wadi Bani Khalid, the geographically most remote population. Clade 3 comprises all other populations investigated including that of Al Hoota Cave. The latter forms a haplogroup which also includes individuals from the adjacent surface population.ConclusionsOur data indicates that the troglomorphic cave population is of quite recent origin supporting the hypothesis that selection drives the fast evolution of troglomorphic traits. In this context pleiotropic effects might play an important role as it has been shown for Astyanax. There seems to be some gene flow from the cave population into the adjacent surface populations. One blind individual, found at a surface locality geographically distinct from Al Hoota Cave, is genetically differentiated from the other blind specimens indicating the probable existence of another cave population of G. barreimiae. The phylogeographic analyses show that while some of the surface populations are either still in contact or have been until recently, the population Wadi Bani Khalid is genetically separated. One group consisting of three populations is genetically highly differentiated questioning the conspecifity with G. barreimiae.

Prochloraz effects on biomarkers activity in zebrafish early life stages and adults

Zebrafish early life stages (ELS) assays have been increasingly used to assess the toxicity of chemicals and waste waters, showing a great potential due to the wide variety of endpoints that can be incorporated in the test. Moreover, zebrafish ELS test have been proposed, mainly for ethical reasons, as a surrogate for tests with adults. In this work, the fungicide Prochloraz (PCZ) was used as a chemical model to compare sensitivities of embryos/larvae and adult zebrafish focusing on lethality and biomarkers as endpoints. Effects on embryo development were also assessed. Organization for economic cooperation and development (OECD) guidelines were followed and adapted to include the analyses of the biomarkers cholinesterase, glutathione S-transferase, and lactate dehydrogenase. The acute toxicity of PCZ for zebrafish ELS and adults seemed to be similar with 96 h-LC₅₀ values of 8.5 and 4.6 mg/L, respectively. However, biomarkers were only responsive in larvae indicating a higher sensitivity of this life stage at sublethal level. PCZ also proved to be teratogenic: at intermediate concentrations effects on embryo development could be noticed, including spine deformations, edemas, lack of pigmentation, slower heart rate, and complete hatching failure. At the lowest concentrations, the more relevant effects (edemas and abnormal absorption of the yolk sac) were observed after hatching. The measurement of biomarkers in the zebrafish ELS assay seems to a useful tool in the detection of chemical effects showing higher sensitivity than adults. Further research should focus on the link between biomarkers responses in larvae and effects at later life stages of zebrafish.

The Body as a Biological and Genetic Entity

What is meant by a genetic disorder? To the biologist, the lack of pigment when the situation is pigmentation is an abnormality. An albino alligator, an albino giraffe, or an albino tiger stands out and surprises the beholder, because in the experience of those who have observed populations of alligators, giraffes, or tigers, these are rare. We may have difficulty defining what is normal among humans but there is a huge quantitative distinction between the words typical and When an unusual event is one in several tens of thousands, it is atypical. But the problem is more than a quantitative one. If we do think dualistically about that which harms us and that which benefits us when it comes to alien life in our bodies, should we also think that way about gene mutations?

Pectoral fin loss in the Mastacembelidae: a new species from Lake Tanganyika

Pectoral fin loss is a dramatic evolutionary phenomenon that has occurred independently in different teleost lineages. Here, we report the first case of pectoral fin loss in the Mastacembelidae (Teleostei: Synbranchiformes), with the discovery of a new species of mastacembelid from Lake Tanganyika (LT), Mastacembelus apectoralis sp. nov. M. apectoralis can be distinguished from all other mastacembelid species by its complete loss of pectoral-fin rays, distal pectoral radials and pectoral radials, as well as a reduction in pectoral girdle elements that include smaller and less well-developed coracoid and minute scapular bones. Other distinguishing characteristics include a near absence of scales, lack of pigmentation and the presence of well-developed adductor muscles. A previous multigene phylogeny of mastacembelids placed M. apectoralis sp. nov. within the LT species flock, having diverged from its sister species Mastacembelus micropectus∼4.5 million years ago. M. micropectus also shows a reduction in the size of its pectoral fin and endoskeletal girdle, and has largely cartilaginous pectoral radials and a reduced number of pectoral-fin rays. Here, we compare the pectoral girdle of M. apectoralis and M. micropectus with LT and non-LT African mastacembelids. M. apectoralis is currently only known from its type locality, Cape Kachese, Zambia, where it occurs in sympatry with several other LT mastacembelids, including its sister species M. micropectus. The loss and reduction of pectoral fins and associated girdle elements in M. apectoralis represents another independent occurrence of this evolutionary phenomenon within the teleosts. The discovery of this species highlights the exceptional diversity of this biodiversity hotspot, the understanding of which is of critical importance with the pressures of pollution, overfishing and climate change threatening the speciose and evolutionarily significant diversity of this ancient lake.

A case of leucism in the burrowing owl Athene cunicularia (Aves: Strigiformes) with confirmation of species identity using cytogenetic analysis

Leucism is an inherited disorder, characterized by the lack of pigments in part or all of the body, normal coloration of the eyes and, in birds, in naked parts such as the bill and legs. This kind of disorder is sometimes erroneously designated as albinism or partial albinism. In this study, we present a case of leucism in a wild owl. The studied individual presented completely white plumage, light-yellow coloration of legs and bill and normal coloration of eyes. According to morphological features, this owl is a specimen of burrowing owl, Athene cunicularia (Molina, 1782). To confirm the species identity, we used cytogenetic analyses for karyotypic determination, comparing it to the previously described one in the literature. We also studied a captive female of A. cunicularia to complement the species karyotype, which was described in the literature based only on a single male. The karyotype of the leucistic owl individual was compatible with the previously published one for A. cunicularia, confirming the bird was a male specimen. Cytogenetic analysis of the captive female showed that the W sex chromosome is metacentric and comparable to the seventh pair in size. This is the first description of a case of leucism in A. cunicularia for South America. Long-term studies are needed in the Neotropical region to evaluate survival and breeding success in leucistic birds.