The Zungaro jahu is an important large catfish of the order Siluriformes that is in danger of extinction due to habitat destruction. Studies on its biology are scarce and the majority relates only to nutrition or parasitology. In order to provide greater information on its morphology and aid husbandry and larviculture studies, the aim of this study was to characterize larval development in Z. jahu from hatching to total yolk absorption. Samples were collected at pre-established times, processed, stained, and analyzed under stereomicroscopy, light microscopy, and scanning electron microscopy. Total yolk absorption was observed by 60 hours post-hatching (hph) at 28.75 ± 0.59°C. The newly hatched larvae showed slightly pigmented body, the outline of the digestive tract, evident eyes, and the first swimming movements. Mouth opening took place at 12 hph and the connection between the oral cavity and the rudimentary intestine was observed at 24 hph. Were analyzed the main larval organs and systems: digestive organs, heart, gill arches, sensory system, thyroid, kidney, and swim bladder. As the larvae grew, these organs became more mature and functional. The development of the sensory and feeding structures was observed at the start of larval development, and thus before depletion of endogenous energy reserves, the strategy for this species is to increase its chances of survival in the environment.

Engraulids, also known as anchovies, are a distinctive group of clupeoid fishes characterized by a series of derived morphological features of the snout and infraorbital bones, suspensorium and branchial arches. Although anchovies are very abundant today, they are scarcely represented in the fossil record. A new genus and species of anchovy, †Eoengraulis fasoloi gen. et sp. nov., is described from the Eocene (late Ypresian, c. 50 Ma) locality of Monte Bolca, Italy. It is based on a single well-preserved articulated skeleton that exhibits a unique combination of characters that supports its recognition as a new genus of the family Engraulidae, including: nine branchiostegal rays; 40 preural vertebrae and 17 pairs of pleural ribs; pleural ribs – preural vertebrae ratio 0.42; seven supraneurals; dorsal-fin origin at about mid-length of the body; about 16 dorsal-fin rays; anal-fin origin slightly behind the base of the last dorsal-fin ray; 19 anal-fin rays; seven pelvic-fin rays; and small needle-like pre-pelvic scutes. The morphological structure of the single available specimen suggests that †Eoengraulis fasoloi is the sister taxon of all other engrauline taxa. †Eoengraulis fasoloi is the oldest member of the family Engraulidae known to date. This taxon suggests that the earliest phases of diversification of engrauline anchovies probably occurred in the coastal palaeobiotopes of the western Tethys during Eocene time.

Batfishes of the family Ogcocephalidae are derived lophiiform fishes characterized by having a dorsoventrally depressed body and a distinctive series of morphological features. A new genus and species of batfish, Tarkus squirei gen. et sp. nov., is described from the Eocene (Ypresian) limestone of the celebrated locality of Monte Bolca, Italy. It is based on five well-preserved specimens that display a unique combination of characters (body moderately depressed; disk rounded in outline; caudal peduncle thick and stout; frontals with median groove for the illicium; teeth present on jaws and palate; illicial bone pitted and trilobate; body covered with thick slightly overlapping tubercles) that support its recognition as a new genus of the family Ogcocephalidae. Tarkus gen. nov. is also characterized by having distally branched pectoral-fin rays, a condition unique within the family, and by a peculiar structure of the axial skeleton, which possibly represents the plesiomorphic state for the ogcocephalids. Tarkus gen. nov. shows a certain degree of phenetic affinity with the extant shallow-water batfish genera Halieutaea and (more particularly) Halieutichthys. The specimens of this taxon are the first articulated skeletal remains of the Ogcocephalidae ever recorded as fossils, also representing the oldest members of the family known to date. The general structure of the skeleton of Tarkus gen. nov. provides unambiguous evidence that the existence of the modern ogcocephalid body plan was already established in the early Eocene, and probably originated well before that period. Palaeoenvironmental considerations suggest that Tarkus gen. nov. was a tropical batfish that inhabited the inner-shelf palaeobiotopes of the central-western Tethys.

A new genus and species of deep-sea hatchetfish, Discosternon federicae gen. et sp. nov., is described from the Middle Miocene (Serravallian) calciturbititic deposits of the Tufillo Unit exposed near the town of Gessopalena, central Italy. It is based on a single, very small, well-preserved and nearly complete specimen that exhibits a discoid physiognomy and a unique combination of features, many of which are reductive (loss of dorsal blade, loss of anal-fin hiatus, loss of abdominal keel-like structure, reduction of number of supraneurals, reduction of number of caudal vertebrae, presence of slender neural and haemal spines, external surface of cleithrum smooth). The comparative morphological analysis indicates that Discosternon is probably related to the derived genera Horbatshia and Sternoptyx. The highly reduced body size and the possession of many reductive characters indicate that Discosternon can be presumed to be a miniature fish. Anatomical and morphofunctional considerations suggest that Discosternon possibly was a midwater plankton feeder characterized by a reduced locomotory ability.

The first fossil ribbonfish, Trachipterus mauritanicus sp. nov., based on a single specimen, is described from Sidi-Brahim, an Upper Miocene (Messinian) locality situated in the central sector of the Chelif Basin, northwestern Algeria. Trachipterus mauritanicus sp. nov. is characterized by a flattened neurocranium and an advanced insertion of the dorsal fin. Based on skeletal morphology, T. mauritanicus sp. nov. appears to be related to T. arawatae and T. trachypterus. Trachipterus mauritanicus sp. nov. represents the eighth taxon described up to now from Sidi-Brahim. The occurrence of the first fossil member of the family Trachipteridae from the Upper Miocene sediments of northwestern Algeria emphasizes the crucial importance of the Messinian ichthyofaunas from Algeria to our knowledge of the fossil record of the Teleostei.

A new fossil teleost, belonging to the family Aspidorhynchidae Nicholson & Lydekker, Aspidorhynchus antarcticus sp. nov., was obtained from a block of reworked Upper Jurassic tuffaceous mudstone in the lower (Albian) part of the mid-Cretaceous Whisky Bay Formation of James Ross Island, Antarctic Peninsula. Additional material, assignable to Aspidorhynchus sp., was collected from in situ Upper Jurassic marine rocks (Nordenskjöld Formation) at Longing Gap, northern Antarctic Peninsula. Not only is this the first reported occurrence of the family from Antarctica, it is also the first unequivocal record of Aspidorhynchus outside Europe; prior to this discovery, the genus had only been reported with certainty in marine deposits from the Middle Jurassic to Lower Cretaceous of England, France and Germany. This is the earliest neopterygian fish so far recovered from marine rocks in the Antarctic.

The Hoplias malabaricus primary spermatogonium shows a large nucleus, central nucleolus, and low electron-dense cytoplasm containing nuages. In cysts, they undergo several mitotic divisions with incomplete cytokinesis, giving rise to secondary spermatogonia. These are smaller than the primary spermatogonia and their nuclei have one or two eccentric nucleoli. Spermatocytes I can be identified by the presence of synaptonemal complexes. Spermatocytes II are smaller than spermatocytes I, displaying roughly compacted chromatin. All these cell types remain interconnected by thick-walled intercellular bridges, which have membranous reinforcements during mitosis and meiosis. These cell types show a well-developed endomembranous system, one of the centrioles anchored to the plasma membrane and small nuages. Their mitochondria are large and circular, with few cristae. In the last generations of spermatogonia, the mitochondria are smaller, elongate and have more cristae. In the spermatocytes, the mitochondria are small and round. Similarities found in relation to germ cells of other teleosts are discussed.

Deux séries d'expériences ont été menées, les unes en étang de pisciculture, les autres en laboratoire, pour déterminer la relation entre conditions thermiques et durée de l'incubation chez l'Atipa [Hoplosternum littorale (Hancock, 1828)]. En milieu contrôlé, 36 °C constituerait la limite supérieure de la température d'incubation permettant la survie des œufs. La température minimum testée, 24 °C, ne constitue pas la limite inférieure permettant la survie des œufs. La durée minimale d'incubation, évaluée à 36 heures, serait obtenue pour une température d'incubation de 33,6 °C. La quantité minimum d'énergie fournie par l'environnement pour obtenir l'éclosion est exprimée en degrés-heures et s'élèverait à 1 201 °C × h pour la température d'incubation de 31,3 °C. Une typologie du développement embryonnaire de l'espèce, directement inspirée de celle de Ballantyne (1930), a été calée sur une échelle exprimée en °C × h. En étangs, les conditions de température au sein de la ponte, plus élevées que celles de l'air, sont sensiblement identiques à celles de l'eau environnante et relativement stables d'une expérience à l'autre (27 à 29 °C en moyenne). Le temps d'incubation observé sur l'ensemble des 9 nids équipés de capteurs varie de 47 à 54 heures. A temps d'incubation égal, le nombre de degrés-heures nécessaires pour obtenir l'éclosion est plus important en étang qu'en milieu contrôlé. La discussion porte sur le rôle du nid dans la reproduction de l'espèce.