RESUMO
Two hyperapolytic species of Acanthobothrium Blanchard, 1848 have been collected from Discopyge tschudii Heckel, 1846 and Zapteryx brevirostris (Müller et Henle) along the coast of Argentina. Acanthobothrium stefaniae sp. n. from D. tschudii is a category one species (i.e., it is less than 15â¯mm in total length, possesses fewer than 50 proglottids, fewer than 80 testes and essentially symmetrical ovary), and differs from all congeners by the following combination of features: proglottid hyperapolysis, hook morphology, size and shape of the cirrus sac, and by having spinitriches in the distal bothridial surface. This is the first record of Acanthobothrium in Discopyge Heckel, 1846. The specimens from Z. brevirostris conform to the morphology of Acanthobothrium zapterycum Ostrowski de Núñez, 1971. A redescription of this species is presented, which expands most ranges of measurements originally given, and provides details omitted in the original description, including the microthrix pattern. This study allowed us to observe the intraspecific variation in ovarian symmetry in A. zapterycum, which shed some doubt on the validity of this as a diagnostic feature. The reproductive strategy (apolysis) of several species of Acanthobothrium was reviewed and summarized.
Assuntos
Cestoides/anatomia & histologia , Cestoides/isolamento & purificação , Infecções por Cestoides/veterinária , Elasmobrânquios/parasitologia , Doenças dos Peixes/parasitologia , Animais , Argentina/epidemiologia , Cestoides/classificação , Cestoides/ultraestrutura , Infecções por Cestoides/epidemiologia , Infecções por Cestoides/parasitologia , Feminino , Doenças dos Peixes/epidemiologia , Microscopia Eletrônica de Varredura , Ovário/ultraestrutura , Reprodução , RajidaeRESUMO
The present study provides quantitative and qualitative analyses of the dentition of Discopyge tschudii. Overall, 193 individuals (99 males and 94 females) of D. tschudii were collected on scientific trawl surveys conducted by the National Institute for Fisheries Research and Development (INIDEP) and commercial vessels in Argentina. Discopyge tschudii has rhombic-shaped teeth, arranged in a semipavement-like dentition; each tooth has an erect cusp slightly inclined posteriorly and holaulachorized root. Mature males have greater tooth lengths than females and immature specimens. Discopyge tschudii exhibits dignathic homodonty and gradient monognathic heterodonty where teeth of the commissural row are shorter than those of the symphyseal and internal rows.