RESUMO

Guitarfishes and sawfishes are included in the order Rhinopristiformes, which currently encompasses five families: Pristidae, Rhinobatidae, Trygonorrhinidae, Rhinidae and Glaucostegidae. Considering the low number of studies focused on oral structures in Rhinopristiformes and the need to better understand their internal morphology, this study aimed to (1) evaluate and describe the morphological variation of the oropharyngeal denticles of guitarfishes and sawfish; (2) evaluate and describe the ontogenetic and sexual variation of the oropharyngeal denticles of Zapteryx brevirostris; (3) propose characters potentially useful for taxonomic and systematic purposes and (4) discuss the possible functions and advantages of these structures. Tissue samples were taken from the oropharyngeal region of specimens preserved in 70% alcohol and then prepared for visualization in scanning electron microscopy. A new method for sampling the pharynx region is proposed herein. Considerable morphological variation between families and genera was observed. However, no variation between conspecifics was found. Regional variations of denticles when examining a single individual were observed in shape, ornamentation, and orientation. In Zapteryx brevirostris, males had a significantly higher density of denticles in the ventral region than females and lower densities were observed in juveniles. The four characters discussed here are based on the presence of keels, number of cusps, distal end elongation and width/length ratio of the oropharyngeal denticles. Among the possible functions and advantages of these structures are the improvement of food adherence, tissue protection against food abrasion and parasitism, and attenuation of hydrodynamic drag in the oropharyngeal cavity during food ingestion.

Assuntos

RESUMO

Although the diversity of animal groups distributed in Brazil provides countless research opportunities, the current scenario does not follow this demand. The reasons for the disconnections range from inequality in the availability of resources for teaching and research to the focus of researchers on specific groups of animals, while others remain neglected. Training new potential Brazilian researchers interested in Zoology is essential for a greater understanding of this diversity, as well as exposing those potential new researchers to new groups and different work possibilities. Thus, the Summer Course in Zoology (in Portuguese, CVZoo) promoted by the Graduate Program in Zoology at the University of São Paulo, over the last ten years, has been seeking to contribute to this training of new researchers in the field of Zoology, as well as in updating teachers through university extension activities. In order to assess the impacts caused by CVZoo on the academic and professional training of the participants, Google forms were sent to participants in the ten editions of the course, as well as compiled information available on the Lattes Platform. Qualitative and quantitative analyses showed the profile of graduates, their expectations, and perceptions about the course. Based on these data, we demonstrate the CVZoo's efficiency in popularizing Zoology throughout the country in contributing to the decentralization of knowledge as well as in meeting the urgent concerns of making access to knowledge more egalitarian and socially fair.

Embora a diversidade de grupos de animais existentes no Brasil ofereça inúmeras oportunidades de estudo, o cenário atual não acompanha essa demanda. Os motivos para essa desconexão vão desde a desigualdade na disponibilidade de recursos para ensino e pesquisa até o foco de pesquisadores em grupos específicos de animais, enquanto outros permanecem negligenciados. O treinamento de novos pesquisadores interessados em Zoologia é essencial para um maior entendimento da diversidade brasileira, assim como a exposição de tais pesquisadores a novos grupos e diferentes possibilidades de trabalho. O Curso de Verão em Zoologia (CVZoo) promovido pelo Programa de Pós-graduação em Zoologia da Universidade de São Paulo, ao longo de dez anos vem buscando contribuir para a formação de novos(as) pesquisadores(as) na área da Zoologia, bem como na atualização de docentes do Ensino Básico por meio de atividades de extensão universitária. Para avaliar os impactos causados pelo CVZoo na formação acadêmica e profissionalizante dos participantes, foram enviados formulários aos participantes das dez edições do curso, bem como compiladas informações disponíveis na Plataforma Lattes. Análises qualitativas e quantitativas evidenciaram o perfil das pessoas egressas, suas expectativas e percepções acerca do curso oferecido. Com base nesses dados, é apontada a eficiência do CVZoo na popularização da Zoologia por todo o país, contribuindo para a descentralização do conhecimento, bem como atendendo às preocupações prementes de tornar o acesso ao conhecimento mais igualitário e socialmente justo

RESUMO

Skates of the order Rajiformes are known to perform benthic locomotion by using their specialized bilobed pelvic fins and thus walking or punting on the substrate. Several studies have investigated the pelvic fin and girdle skeleton but little is known about the muscles responsible for walking performance. The goals of this study, therefore, are to investigate, describe, and illustrate the morphological variation in pelvic musculature among skate species and to discuss the phylogenetic and locomotor implications of the conditions observed. Specimens belonging to 19 of the 36 skate genera currently valid for the order Rajiformes were manually dissected and specimens of Narcine, Tetronarce, and Zapteryx were also examined as comparative material. The pelvic musculature varies among skates, mainly regarding the extension of ventral and dorsal muscles related to the anterior lobe of pelvic fin. All rafijorms examined and the torpediniforms Narcine and Tetronarce possess a complex pelvic musculature associated to the anterior pelvic lobe, which is herein suggested as a synapomorphy of Batoidea with independent losses in guitarfishes and stingrays. Nevertheless, the examination of additional taxa is required to better understand the evolution of pelvic musculature within batoids. The morphological variation observed could indicate different walking abilities as discussed herein but further studies on the locomotion behavior in skates are needed to confirm these assumptions.

Assuntos

RESUMO

Of the almost 1,300 currently known Chondrichthyan species, 13.4% occur in Brazilian marine and freshwater environments and more than a half are under extinction threat. There are three main scientific events in Brazil committed to present and discuss research on fishes (including Chondrichthyes): EBI, SBEEL, and ISPCNF. We analyzed 1,584 submitted abstracts to these events over the last 30 years and noticed that, within Chondrichthyes, studies regarding Systematics were less representative (17%). However, the most shocking result concerned the proportion of women in authorship: almost 30% of abstracts were co-authored only by men, and only 25% of those in Chondrichthyan Evolution had women as last authors, demonstrating that a few women are acting as principal investigators in this area of research in Brazil since they might be leaving academia due to lack of support. Besides, the orders Carcharhiniformes and Myliobatiformes represented 66.9% of all studied taxa throughout the years, revealing a research bias on studied taxa which in turn has impacted directly on our knowledge of Chondrichthyan biodiversity and conservation planning. Most importantly, the neglected area of taxonomy needs to be enhanced to allow for appropriate species identification and threatening status evaluation.(AU)

De quase 1300 espécies de Chondrichthyes atualmente conhecidas, 13,4% ocorrem no Brasil em ambientes marinhos e de água doce, sendo que mais da metade está ameaçada de extinção. Há três grandes eventos científicos no Brasil dedicados à apresentação de pesquisas sobre peixes (incluindo Chondrichthyes): EBI, SBEEL, ISPCNF. Analisamos 1584 resumos enviados a esses eventos nos últimos 30 anos e percebemos que, dentro de Chondrichthyes, estudos relacionados à Sistemática foram raros (17%). Porém, o resultado mais impactante diz respeito à proporção de mulheres na coautoria: quase 30% dos resumos foram co-autorados exclusivamente por homens e somente 25% daqueles em Evolução de Chondrichthyes tiveram mulheres como últimas autoras, demonstrando que poucas mulheres estão atuando como pesquisadoras principais nessa área de pesquisa no Brasil já que elas podem deixar o ambiente acadêmico devido à falta de suporte. Além disso, as ordens Carcharhiniformes e Myliobatiformes representaram 66,9% de todos os táxons estudados ao longo dos anos, revelando um viés com relação aos táxons estudados, o que por sua vez tem impactado diretamente no nosso conhecimento da biodiversidade de Chondrichthyes e planejamento da conservação. Mais importante, a negligenciada área da taxonomia necessita ser aprimorada para permitir identificação adequada das espécies e a avaliação dos seus estados de ameaça.(AU)

Assuntos

RESUMO

Rays of the superorder Batoidea comprise the most diverse group of chondrichthyans in terms of valid species and morphological disparity. Up to the present little agreement is observed in studies based on morphological and molecular data focused on uncovering the interrelationships within Batoidea. Morphology-based phylogenies of batoids have not included characters related to the afferent branchial arteries, and little is known about the variation in this anatomical complex in rays. Herein, representatives of 32 genera from 19 families currently recognized of rays were examined as well as some shark taxa. Seven new characters are proposed and tested in two different analyses, one on their own and in the other they were added to the morphological data matrix of the most recent analysis of interrelationships within Batoidea. The arrangement of afferent branchial arteries differs mainly among orders and families of batoids. The absence of a common trunk from which the three posteriormost afferent arteries branch is interpreted as a synapomorphy for Myliobatiformes and the presence of a coronary cranial artery as an autapomorphy for Mobula hypostoma. A close spatial relationship between the second and third afferent arteries within the common branch from the ventral aorta is proposed as a synapomorphy for Rajiformes with a secondary modification in Sympterygia. Data about patterns in afferent branchial arteries in additional taxa such as Squaliformes and Chimaeriformes are needed to better understand the evolution of this character complex among chondrichthyans.

Assuntos

RESUMO

The definition and scope of the genus Carcharhinus has undergone several changes over the years and recent molecular studies have questioned its monophyly by the inclusion of other carcharhinid genera. Although many descriptions of chondrocranium are available for Carcharhinus species, some inconsistences and divergences are found in the literature, mainly regarding the foramina of the orbital region. In this study, the chondrocranium of the silky shark, Carcharhinus falciformis, from specimens caught at the Brazilian coast and the terminology of its components is revised has been described. Chondrocrania of other Carcharhinus species and carcharhinid genera are also examined in order to investigate the phylogenetic significance of chondrocranial morphology. Three new anatomical terms and nine chondrocrania characters are proposed and described in detail. The chondrocranial morphology varies widely among Carcharhinus species mainly regarding the rostrum and nasal capsules. The chondrocrania of Prionace, Nasolamia, and Negaprion are similar to Carcharhinus species and reveal the need to further explore the relationships among these genera. Characters potentially informative for systematics are the shape of rostral node, the preorbital process, and the subethmoidal fossa, and the occurrence of an epiphyseal notch and foramen, and must be included in phylogenetic studies encompassing other carcharhiniforms.

Assuntos

RESUMO

Abstract The skate genus Atlantoraja is composed of three species (A. castelnaui, A. cyclophora, and A. platana) which differ from the other Riorajini species, Rioraja agassizii, in regards to their clasper features, squamation and presence of a caudal fin. Despite of being distributed along Southwestern Atlantic and commonly captured by fisheries in Brazil, Uruguay and Argentina, detailed accounts on external and internal morphology are scarce and the taxonomic status of Atlantoraja species was not revised so far. The aim of this study, therefore, is to review the taxonomy of the genus Atlantoraja, updating information on type specimens and clarifying misidentifications among species, and to describe in detail anatomical structures such as neurocranium, visceral arches, pelvic girdle, dermal denticles and teeth. Lectotypes and paralectotypes are designated for Atlantoraja castelnaui and A. cyclophora. Notes on intraspecific variation within species are also provided. Atlantoraja cyclophora and A. platana are more similar to each other than to A. castelnaui in regards to the squamation (body dorsal surface smooth vs. densely covered by prickles) and color pattern of body dorsal surface, position of orbital foramina, overall shape of neucrocranium and body measurements. Lastly, we discuss the morphological differences among species of Atlantoraja and recommend the inclusion of characters presented here in future cladistic analyses.

Resumo O gênero Atlantoraja é composto por três espécies (A. castelnaui, A. cyclophora e A. platana), as quais diferem da outra espécie da tribo Riorajini, Rioraja agassizii, em relação a características do clásper, escamas e presença de uma nadadeira caudal. Apesar de serem distribuídas ao longo do Atlântico Sul Ocidental e serem comumente capturadas em atividades pesqueiras do Brasil, Uruguai e Argentina, descrições detalhadas sobre a morfologia externa e interna são escassas e o status taxonômico das espécies de Atlantoraja não foi revisado até então. O presente estudo tem como objetivos: revisar a taxonomia do gênero Atlantoraja, atualizando as informações sobre espécimes-tipo e elucidando erros de identificação entre as espécies, e descrever estruturas anatômicas, tais como neurocrânio, arcos viscerais, cintura pélvica, dentículos dérmicos e dentes. Lectótipos e paralectótipos são designados para Atlantoraja castelnaui e A. cyclophora. Notas sobre a variação intraespecífica em cada espécie também são fornecidas. Atlantoraja cyclophora e A. platana são mais similares entre si do que A. castelnaui em relação às escamas (superfície dorsal do corpo lisa vs. densamente coberta por dentículos dérmicos), padrão de colorido da superfície dorsal do corpo, posição dos forâmens orbitais, formato geral do neurocrânio e medidas corpóreas. Por fim, comparações morfológicas entre as espécies de Atlantoraja são realizadas, recomendando-se a inclusão dos caracteres aqui apresentados em análises cladísticas futuras.

RESUMO

Rioraja agassizii belongs to the monotypic genus Rioraja and differs from the other Riorajini species of the genus Atlantoraja by the shape of anterior nasal flap, squamation, clasper skeleton, body measurements and color pattern. Although R. agassizii is a well-known species, commonly captured in inshore waters of the southwestern Atlantic, its external morphology and internal anatomy have never been fully described and little is known on intraspecific variation within the species. Juvenile and adult, male and female specimens were examined, measured and dissected. Herein, we redescribe the species and present detailed descriptions and illustrations of external morphology, neurocranium, jaws, hyoid and gill arches, and pelvic fin and girdle. Additionally, notes on sexual dimorphism and ontogenetic differences in coloration, body and cranial measurements, and dermal denticles are provided.(AU)

Rioraja agassizii pertence ao gênero monotípico Rioraja e difere das demais espécies da tribo Riorajini classificadas no gênero Atlantoraja pelo formato da aba nasal anterior, escamas, esqueleto do clásper, medidas corpóreas e padrão de coloração. Embora R. agassizii seja uma espécie bem conhecida, comumente capturada em águas costeiras do Atlântico Sul Ocidental, sua morfologia externa e anatomia interna não foram totalmente descritas e pouco se sabe sobre a variação intraespecífica nesta espécie. Espécimes juvenis, adultos, machos e fêmeas foram examinados, medidos e dissecados. Neste estudo, a espécie é redescrita e descrições detalhadas e ilustrações da morfologia externa, neurocrânio, maxilas, arcos hioide e branquiais, nadadeira e cintura pélvicas são apresentadas. Adicionalmente, notas sobre dimorfismo sexual e variação ontogenética na coloração, medidas corpóreas e craniais, e dentículos dérmicos são fornecidas.(AU)

Assuntos

RESUMO

The following letter, from a network of women zoologists, is a reply to the article of AlShebli et al. (2020), which suggests that female protégés reap more benefits when mentored by men and concludes that female mentors hinder the success of their female protégés and the quality of their impact. This contribution has two parts. First, we highlight the most relevant methodological flaws which, in our opinion, may have impacted the conclusions of AlShebli et al. (2020). Second, we discuss issues pertaining to women in science, bring a perspective of Women in Zoology and discuss how current diversity policies are positively changing our field.(AU)

Assuntos

RESUMO

The following letter, from a network of women zoologists, is a reply to the article of AlShebli et al. (2020), which suggests that female protégés reap more benefits when mentored by men and concludes that female mentors hinder the success of their female protégés and the quality of their impact. This contribution has two parts. First, we highlight the most relevant methodological flaws which, in our opinion, may have impacted the conclusions of AlShebli et al. (2020). Second, we discuss issues pertaining to women in science, bring a perspective of Women in Zoology and discuss how current diversity policies are positively changing our field.

Assuntos