Nelson Ferreira-Jr

Castoraeschna corbeti sp. nov. from Floresta Nacional de Carajés, Paré state, Brazil (Odonata: Aeshnidae)

Abstract Castoraeschna corbeti sp. nov. is described and diagnosed based on four males (holo- type: Brazil, Para State, Floresta Nacional de Carajás [6°06′13.9″S, 50°08′13.1″W, ca 600 m a.s.l.], 28 ix 2007 to be deposited in Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro). This species is similar to C. longfieldae and C. coronata but can be distinguished mainly by the absence of medio-dorsal spots on S8; postero-dorsal spots on S8-9 very narrow; cerci external margin almost straight in lateral view, without a distinct angulation between stem and base of lamina; cerci apex blunt. The probable ultimate stadium larva is described based on two individuals, male and female, collected at the type locality. Adults were observed flying along margins of a small shaded second-order stream where the larvae were taken. The surrounding forest is under impact of iron ore extraction and will probably disappear in the next years.

Descrição da larva de terceiro ínstar de Megadytes latus (Fabricius) (Coleoptera, Dytiscidae).

The last instar larva of M. latus (Fabricius, 1801) is described and figured, based on reared specimens from Serra dos Orgaos, Teresopolis, state of Rio de Janeiro, Brazil. Some notes on the biotope are provided.

Four new species and first nominal record of Chasmogenus Sharp, 1882 (Coleoptera: Hydrophilidae) from Brazil

The genus Chasmogenus Sharp, 1882 (Hydrophilidae: Acidocerinae) is recorded from Brazil for the first time. Four new species are described and illustrated from the Southeastern Region of the country: C. fluminensis sp. nov. (Rio de Janeiro State), C. lilianae sp. nov. (Rio de Janeiro State), C. itatiaia sp. nov. (Minas Gerais and Rio de Janeiro States), and C. ubatuba sp. nov. (São Paulo State). Chasmogenus sapucay Fernández, 1986 is recorded for the first time from Northern and Southeastern Brazil. Notes on morphology and an updated key for the South American species are provided.

A new species and new records of Oocyclus Sharp, 1882 (Coleoptera: Hydrophilidae) from Brazil

A new species of Oocyclus Sharp, 1882, O. pilosus sp. nov. is described and illustrated from Mato Grosso State in Central-Western Brazil. Oocyclus itapecum Clarkson Short 2012 and O. yubai Clarkson Short 2012 are newly recorded from São Paulo and from Mato Grosso, Goiás and Paraná States respectively. The doubtful record of Oocyclus aeneus Clarkson Short 2012 in Mato Grosso State is herein confirmed. An updated key to the Brazilian species of Oocyclus is provided.

On Brazilian Helobata Bergroth, 1888 (Coleoptera: Hydrophilidae): description of two new species, new records, and key to species

Two new species of Helobata Bergroth, 1888 (Hydrophilidae: Acidocerinae) from Brazil are described and illustrated. Helobata amazonensis sp. nov. is described based on an adult male specimen from the Amazon River floodplains, Amazonas State. Helobata pantaneira sp. nov. is described based on an adult male specimen collected from swamps in the Pantanal biome, in Mato Grosso State. Helobata corumbaensis Fernández & Bachmann, 1987, H. larvalis (Horn, 1873) and H. quatipuru Fernández & Bachmann, 1987 are recorded for the first time from Mato Grosso; Amazonas, Ceará and Mato Grosso; and Rio de Janeiro States respectively. Diagnosis, illustrations, a checklist and a key to Brazilian species of Helobata are provided.

Two new species and new records of Liocanthydrus Guignot (Coleoptera, Noteridae) from Brazil.

Two new species of Liocanthydrus Guignot, L. zanclus sp. nov. and L. mecespilus sp. nov., are described and illustrated from the Brazilian states of Goiás and Espírito Santo, Minas Gerais and Rio de Janeiro, respectively. New records from Brazil are also provided: Liocanthydrus clayae (J. Balfour-Browne) from the state of Pará, L. bicolor (J. Balfour-Browne) from the states of Amazonas and Pará and L. uniformis (Zimmermann) from the states of Espírito Santo, Maranhão and Pará. The previous key of Liocanthydrus is modified to include the new species.

A new species and records of Helochares (Insecta: Coleoptera: Hydrophilidae) from Southeastern Brazil

A new species of Helochares Mulsant, 1844 (Hydrophilidae: Acidocerinae) from Brazil is described and illustrated. Helochares (s. str.) atlanticus sp. nov. is distinct mainly by characteristics of the aedeagus whose phalobase is short, narrowed on basal third; parameres are thick, constricted on apical quarter, with small tooth-like projection on outer margin near apex; dorsal lobe longer than ventral lobe, shorter than parameres, very wide at base, abruptly narrowing toward apex until about half of its length where it dilates and divides into two long and narrow projections apart from each other at base, but turned inward at apex; ventral lobe acuminate and symmetrical. The rounded emargination on anteromedial margin of labrum bearing small tooth-like projections and the convex and slightly elevated mesoventral process, without high-elevated carina, also helps in identifying the species. Specimens of the new species were collected in the mountain region of the state of Rio de Janeiro (municipality of Teresopolis) and in the north coast of the state of Sao Paulo (municipality of Ubatuba), both localities in Southeastern Brazil. Helochares (s. str.) oculatus Sharp, 1882 and Helochares (Sindolus) femoratus (Brulle, 1841) are recorded for the first time from the state of Rio de Janeiro.

Five new species of Ytu Reichardt (Coleoptera: Myxophaga: Torridincolidae) and new records from Brazil

The genus Ytu Reichardt is the most diverse within Torridincolidae, currently with 19 species. Five new species are described herein, four of them from various localities in the southeast of Brazil (type localities in parentheses): Ytu hermes sp. nov. (Brazil, Espírito Santo, Dores do Rio Preto, Pedra Menina, Parque Nacional do Caparaó, Cachoeira Sete Pilões); Ytu hypnos sp. nov. (Brazil, Rio de Janeiro, São Fidelis, Serra Bela Joana); Ytu nyx sp. nov. (Brazil, Espírito Santo, Dores do Rio Preto, Pedra Menina, Parque Nacional do Caparaó, Rio São Domingos, Cachoeira do Aurélio); Ytu thanatos sp. nov. (Brazil, Espírito Santo, Castelo, Parque Estadual do Forno Grande). The other new species, Ytu coeus sp. nov. (Brazil, Espírito Santo, Dores do Rio Preto, Pedra Menina, Parque Nacional do Caparaó, nascente do Rio São Domingos) is described from Brazilian States of Espírito Santo and Ceará, the latter being the first record of this genus in northeastern Brazil. Illustrations of habitus and important diagnostic characters are provided. The new species are compared to other similar species of the genus. New records of some other species of Ytu are presented.

Vatellini Sharp (Coleoptera, Dytiscidae) from Brazil: two new species, new records, and a checklist

The tribe Vatellini Sharp, 1882 is composed of 55 species divided in two genera. Even though a recent revision of the tribe was made, Vatellini of the new world are weakly explored with great gaps in the distributions of species. In Brazil the knowledge is based only on a few localities. In this work two new species are described and illustrated, Vatellus caissara sp. nov. and Vatellus yanomami sp. nov.; new records are given for Brazil: Vatellus maculosus Miller, 2005 in the state of Mato Grosso, Derovatellus lentus (Wehncke, 1876) in Amazonas, Pará and Rio de Janeiro, Vatellus lateralis (Sharp, 1882) in Alagoas, Ceará, Espírito Santo, Pará, Pernambuco and Rio Grande do Sul, Vatellus sahlbergi (Sharp, 1882) in Rio de Janeiro, and Vatellus tarsatus (Laporte, 1835) in Pará. A checklist with all species of Vatellini occurring in Brazil is provided and steps for identification of the new species are added in the key of Miller (2005).

Laccomimus xikrin sp. nov. and new records of other species of Laccomimus Toledo & Michat, 2015 (Coleoptera: Dytiscidae: Laccophilinae) from Brazil

The genus Laccomimus Toledo & Michat, 2015 was recently erected for small drop-shape Dytiscidae beetles commonly found in Tropical South America associated with lentic waters. In the present paper a new species, Laccomimus xikrin sp. nov., is described and illustrated. New records from Brazil are presented for Laccomimus alvarengi Toledo & Michat, 2015 from Amazonas state, L. bordoni Toledo & Michat, 2015 from São Paulo state and L. variegatus Toledo & Michat, 2015 from Pará state.