Ovarian changes and development of the branchial placenta occurring in Jenynsia lineata (Cyprinodontiformes, Anablepidae).

In viviparous teleosts, intraovarian gestation occurs intrafollicularly, as in poeciliids, or intraluminally, as in goodeids and anablepids. Furthermore, there are two different forms of embryonic nutrition: lecithotrophy and matrotrophy; depending on the species, these can be exclusive or coexist during gestation. In matrotrophic species, nutrients are transmitted from the mother to the embryo and are especially important in species with intraluminal gestation.

Gill morphology and morphometry of the facultative air-breathing armoured catfish, Corydoras paleatus, in relation on aquatic respiration.

The Neotropical armoured catfish Corydoras paleatus is a facultative air-breathing teleost commonly exported as ornamental fish. In this species, air breathing enables it to survive and inhabit freshwater environments with low oxygen levels. Therefore, it is important to analyse the gills from a morphological aspect and its dimensions in relation to body mass with reference to aquatic respiration.

Structure of the gonoduct of the viviparous teleost Cnesterodon decemmaculatus (Jenyns, 1842) (Poeciliidae).

During embryogenesis, teleost females do not develop Müllerian ducts, which form the oviducts in all other vertebrates. Thus, when they reach sexual maturity they do not have oviducts. In viviparous teleosts, the lack of oviducts means that the development of the embryos occurs as an intraovarian gestation, unique among vertebrates.

Pathology associated with three new metacercariae from Argentina with morphological and DNA barcode identification.

In the Laboratory of Parasites of Fishes, Crustaceans and Mollusks (CEPAVE), we undertook a parasitological study on three species of fish from the Espinal and Esteros del Iberá ecoregions of Argentina. Clinostomid metacercariae were found parasitizing Characidium rachovii, Crenicichla vittata and Gymnogeophagus balzanii. In this study, we analysed the damage that these parasites inflict on their hosts through the evaluation of histological sections.

Effect of photoperiod on ovarian maturation in Cheirodon interruptus (Teleostei: Characidae).

Cheirodon interruptus is a ubiquitous small characid that inhabits the Pampean region and commonly used as bait. Its vast market is supplied from the wild population causing a significant environmental impact. In this study, we assess the effect of photoperiod on ovarian maturation in order to evaluate its potential as a tool to manipulate reproduction under artificial conditions.

Histochemical differences along the intestine of Corydoras paleatus (Siluriformes: Callichthyidae).

The Neotropical catfish Corydoras paleatus is a facultative air-breather and the caudal half of the intestine is involved in gas exchange. In South America, air-breathing fishes are found in tropical or sub-tropical freshwaters where the probability of hypoxia is high. The aim of this study was to characterize by traditional histochemical and lectinhistochemical methods the pattern of carbohydrate in the intestinal mucosa.

Immunohistochemical and ultrastructural evidence of functional organization along the Corydoras paleatus intestine.

The Neotropical catfish, Corydoras paleatus (Callichthyidae) is a facultative air-breathing teleost that makes use of the caudal portion of the intestine as an accessory air-breathing organ. This portion is highly modified, being well vascularized with capillaries between epithelial cells, which makes it well suited for gas exchange. Instead, the cranial portion is a digestion and absorption site, as it has a typical intestinal epithelium with columnar cells arranged in a single row, villi and less vascularized tunica mucosa.

A new species of philometrid parasite (Nematoda, Philometridae) and histopathological lesions in juvenile whitemouth croakers, Micropogonias furnieri (Desmarest).

A new species of nematode parasite, Philometroides tahieli sp. nov. is described.

Morphological aspects and histological effects of the attachment organ of Parabrachiella sp. (Copepoda: Lernaeopodidae) on the grey mullet, Mugil liza Valenciennes.

The genus Parabrachiella Wilson, 1915 (Lernaeopodidae) is represented by copepods that are highly adapted to a parasitic way of life. In Argentina, only P. insidiosa var.