Hisonotus

Abstract: A new species of Hisonotus from rio Juma, located at the right margin of the lower rio Aripuana, rio Madeira basin is described. The new species is distinguished from its congeners mainly by a reddish-tipped premaxillary and dentary teeth, a V-shaped spinelet, three lateral plates in abdominal series, the coloration pattern of caudal fin with three transversal dark bars, and by morphometric characters.

Abstract: We analysed the fish assemblage in the "Mergulhiio" stream (soulhem Brazil) with underwater observations for habitat use, considering water depth, current velocity, bottom type, shadow froID vegetation cover, distance of stream-edge, and vertical position. Stomach contents or foregut content samples of the most abundant species were collected from 26 species (lO families). The fish assemblage occupied the bottom stream. The similarity analysis of spalia! occupation of species grouped four habitat use guilds: A) "Iambaris" (Aslyanax sp. and Deutetodon langei), Characidium spp. (C. lane; and C. plerosliclum) and Rineloricaria kronei used the bottom in deep sites and waters with middle current; B) Pimelodella pappenheimi and Corydoras barbalus used the bottom in siles with JOwer cUI'l"ent; C) Mimagoniates microlepis used the surface of the water column; and D) Phalloceros caudimacullUus used shallow sites and waters without current. Species with few records were analysed descriptively. Diet similarity suggested seven trophic guilds: Microglanis sp. and PiTMIodella pappenheimi: omnivorouslca:mivorous gui14; Corydoras barbatus: omnivorous/insectivorous guild; Characidium [ane;: aquatic insectivorous guild, Ilillinly aquatic insects; Mimagoniates microlepis: terrestrial insectivorous guild, mainly te.rrestrial insects; Deuterodon [angei and ASlyanax sp.: omnivorous/herbivorous guild; Rineloricaria kronei, Kronichth.yssubteres, Schizolecis guntheri. Hisonotus leucofrenatus and Pseudotothyris obtusa: herbivOfous guild; and PhaUoceros caudimaculatus: a!givorous guild. When the guilds were similar, the species were geIletalists in diet and in habitat use.

Abstract: The corrego Pauliceia is a direct tributary of the rio Mogi-Guacu, located in Santa Rita do Passa Quatro, State of Sao Paulo, Southeastern Brazil. This stream runs inside a savannah-like (cerrado) environment and it associated vegetation. Biological and ecomorphological aspects of its fish community were studied in three stretches of the stream, denominated herein as the upper, middle and lower courses. The fish fauna recorded in this study consisted of 15 species, belonging to five orders and nine families, based in a total of 715 collected individuals representing 1,450 kg of biomass. The most important abiotic factors related to the occurrence and distribution of the fish fauna were the substrate, current speed, and presence or absence of riparian vegetation. The analysis of 336 stomach contents of 13 species demonstrated that 65% of food items are autochthonous, 32% allochthonous, and 3% are of unknown origin. Four alimentary guilds could be identified, based on the predominant food items: omnivores with tendency to insectivory - Astyanax paranae, A. fasciatus and Piabina argentea; larvivores - Corydoras difluviatilis, Cetopsorhamdia iheringi, Phenacorhamdia tenebrosa, Characidium gomesi, Eigenmannia virescens, and Rhamdia quelen; periphyton feeders - Hisonotus sp., Hypostomus ancistroides and Synbranchus marmoratus; and piscivore - Hoplias malabaricus. Reproductions data are presented for Astyanax altiparanae and Hisontus sp. Three ecomorphological groups could be established, based on swimming, feeding, and microhabitat strategies: nektonic (A. fasciatus, A. paranae, Bryconamericus stramineus, P. argentea, H. malabaricus and Phallotorynus jucundus), benthic (C. gomesi, P. tenebrosa, C. iheringi, R. quelen, C. difluviatilis, H. ancistroides and Hisonotus sp.), and necktobenthic (E. virescens and S. marmoratus).

Abstract: A new species of Hisonotus is described from headwaters of rio Araguaia basin, municipality of Barra do Garcas, Mato Grosso state, Brazil. The new species is distinguished from its congeners by a V-shaped spinelet, yellowish teeth, absence of unpaired platelets at typical adipose fin position, the caudal-fin color hyaline with three transverse dark bars, one abdominal median plate series, and by morphometric and meristic characters.