A new species of the catfish genus Trichomycterus from the La Plata River basin, southern Brazil, with comments on its putative phylogenetic position (Siluriformes: Trichomycteridae)

The genus Trichomycterus is a highly diverse group of Neotropical catfishes that encompass almost 60% of all the currently recognized species of the Trichomycteridae. A new species of this genus, T. perkos, is herein described from tributaries of the Paranapanema and Uruguai River basins, southern Brazil. The new species exhibits a remarkable ontogenetic change in its pigmentation, having a unique color pattern when adult. The adult pigmentation consists of three wide dark brown stripes, located in an inner skin layer of trunk and caudal peduncle, combined with a superficial light brown freckled pattern on the dorsum and caudal peduncle. Small, presumably juvenile specimens lack the superficial freckles but already have the dark stripes, thus resembling the color pattern of a few other congeners. Nevertheless, several unequivocal morphological features distinguish both juveniles and adults of T. perkos from these congeners. In spite of the difficulties in estimating phylogenetic relationships within Trichomycterus, the new species is tentatively proposed as being the sister-taxon of a small group of species composed by T. crassicaudatus, T. igobi, and T. stawiarski.

A New Diminutive Species of Loricaria (Siluriformes: Loricariidae) from the Rio Paraguay System, Mato Grosso do Sul, Brazil

Loricaria coximensis. new species, is described from the Rio Paraguay basin, in Mato Grosso do Sul State, Brazil. It is distinguished from all other species of Loricaria, except L. holmbergi, L. lundbergi, L. parnahybae, and L. pumila by having abdominal plates confined to the pre-anal shield and posterior median abdominal area, usually loosely joined or separated by naked areas, pectoral girdle mostly naked, with isolated plates near base of pectoral fins and posterior to gill opening vs. abdominal plates well developed and tightly arranged across the entire median abdominal area, including the pectoral girdle. It is distinguished from these other four species by meristic counts and several morphometric proportions, particularly a broader head (19.4-21.3% SL vs. 14.1-19.1% SL). Loricaria coximensis becomes the third described paedomorphic species of Loricaria, along with L. nickeriensis and L. pumila, based on its small adult size (<100 mm SL), reduced number of lateral dermal plates, and incomplete abdominal plate development. The new species is presently known only from a limited section of the Rio Coxim, which has been severely impacted by a hydroelectric dam and widespread conversion of land for agriculture.

Review of the Genus Cathorops (Siluriformes: Ariidae) from the Caribbean and Atlantic South America, with Description of a New Species

The New World genus Cathorops in the family Ariidae (Sea Catfishes) includes species that inhabit estuarine and coastal waters as well as freshwaters, playing an important role in Neotropical coastal and estuarine fisheries. The relatively conserved external morphology coupled with the marked sexual dimorphism and ontogenetic variation makes it difficult to recognize and diagnose the species. One of the major problems concerns the nomenclatural and geographical limits, of C. spixii, described from tropical Brazil and often treated as the only coastal marine species in the genus from the Western Atlantic. Examination of types of nominal species as well as comprehensive collections of non-types from Caribbean and Atlantic South America, lead us to conclude that C. spixii is restricted to Brazil and that C. nuchalis is a valid species, ranging from Venezuela to Guyana. The nominal species Arius laticeps, Arius nigricans, and Arius variolosus are synonyms of C. nuchalis, C. spixii, and C. arenatus, respectively. We also describe a new species in the Cathorops mapale species group from Colombia and Venezuela.

Life history of three catfish species (Siluriformes: Ariidae) from southeastern Brazil

This study evaluated the spatio-temporal distribution, reproduction and diet of the catfishes Genidens genidens, G. barbus and Aspistor luniscutis in Caraguatatuba Bay. Their sizes were recorded and the sex and reproductive stage identified. The abundance was compared between areas (South and North) and among months (August 2003 - October 2004). The species had different spatial distributions, allowing them to coexist. The temporal distribution reflected their tendencies to migrate in the reproductive period, as evidenced by the dominance of small immature individuals in the bay. G. genidens tended to reproduce in winter, and A. luniscutis in spring. The diet of G. genidens consisted of crustaceans, mollusks (shells), fish scales, ostracods, and bivalve siphons. G. barbus consumed a high proportion of mysids, followed by fish (bones and scales). For A. luniscutis, the diet was based on fish scales and crustaceans. High quantities of particulate organic matter were observed in the diet of all three species, as previously known for estuarine catfishes. The consumption of fish scales may reflect a lepidophagic habit. A small overlap was observed among the diets, reflecting differences in their environments as well as in the proportions of each item ingested.

Iheringichthys syi (Siluriformes: Pimelodidae), a new pimelodid species from upper Paraná basin, Brazil

We describe a new species of pimelodid catfish of the genus Iheringichthys from the upper Paraná basin, Brazil. Iheringichthys syi n. sp. is distinguished by the comparatively fine serration along the anterior margin of the pectoral-fin spine, an adpressed dorsal-fin remote from the adipose-fin origin, a large eye (23.2-31.2% of head length), narrow interorbital (16.2-23.0% of head length), long snout (42.0-51.0% of head length), long postorbital length (30.6-34.0% of head length), low adipose fin (4.8-7.8% of standard length), eye diameter 97.0-140.0% of interorbital length, and body with numerous, small dots irregularly scattered on flanks, especially marked on anterior half of flank.

Feeding behaviour of the Corydoradinae

The evolution of a sub-family of south-american freshwater catfishes has created a great diversification of its representants into a huge number of species, usually members of characteristic mimicry communities. After the work of Alexandrou (Alexandrou, 2011) on the phylogeny of the group that discovered the existence of more deep divisions, from the taxonomic point of view, of the sub-family, even from the ecological point of view, I tried to reconfirm these statements from the ethological point of view, settling watching and recording sessions and an experiment that could show their interactions on the environment by observing their substrate mixing action.

A phylogenetic analysis of the Asian catfish families Sisoridae, Akysidae, and Amblycipitidae, with a hypothesis on the relationships of the neo-tropical Aspredinidae (Teleostei, Ostariophysi) / Mario C. C. de Pinna.

n.s. no.84(1996)

Some biological and ecological considerations for research in the management of the fisheries of Lakes Victoria and Kyoga

There is little doubt that the exploitation of the current fisheries of Lakes Victoria and Kyoga requires close monitoring with a view to enforce adherence to prudent management practices. Many indigenous fishes have gradually disappeared from the commercial fishery of both lakes. In the Uganda portion of Lake Victoria for instance Okaronon and Wadanya (in press) have shown that:- 1. The once preponderant haplochromiine taxon ceased to feature in the commercial catches in 1979. 2. The lung-fish (Protopterus aethiopicus) which formerly contributed significantly to the commercial landings had declined to minor species status by the mid 1980s. 3. The catfishes Clarias mossambicus and Bagrus docmac, formerly major fish species, contributed insignificant quantities to the commercial fishery since the early and mid 1980s, respectively. Similar trend have been "reported in the Kenya and Tanzania portions of Lake Victoria (Bwathondi, 1985; Mainga, 1985, Witte and Goudswaard, 1985). On the other hand since their establishment all round the lake in the early to mid 1980s some introduced fishes namely Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus) built up impressive stocks in Lake Victoria (Ssentongo and Welcomme, 1985, Okaronon et al. 1985; Okaronon and Wadanya, in press). Togetther with the native pelagic cyprinid Rastrineobola argentea or Dagaa/Mukene the introduced fishes have contributed unprecidented catches, stimulating vibrant commercial fisheries which have yielded significant social economic benefits to the peoples of the three states riparian to the Lake (Reynolds and Greboval, 1988; Kudhongania et al in press). The impressive landings particularly of the Nile perch and Nile tilapia have also led to rapid industrialisation of fish processing in East Africa mainly for the export market. Fish export has now the potential of a major foreign exchange enterprise in the region.