First records of small squaregilled mayflies ( Ephemeroptera , Caenidae ) from the state of Roraima , Northern Brazil

New records and notes on the distribution of the family Caenidae from Roraima state, Brazil are provided. No previous records were known of this family from Roraima. Our study reports four species of Brasilocaenis and Caenis: Brasilocaenis irmleri Puthz, 1975, Caenis chamie Alba-Tercedor & Mosquera, 1999, C. fittkaui Malzacher, 1986 and C. reissi Malzacher, 1986. In addition, an unidentified species of Latineosus, based in a unique exuvia, was also found.

The nymphs of this family can be easily distinguished by the operculated gills of tergum II, which are quadrangular and overlap on median line of body and have a dorsal Y-shaped ridge; the filamentous gills on abdominal segment I; and the absence of hind wing pads.Nymphs occur in a variety of water bodies, including ponds, lakes, streams, and rivers, mostly along the margins on sand with a thin layer of silt but also can be found aggregated in vegetation in areas of flow and in floating lentic plants (Edmunds et al. 1976;Brittain 1982;Edmunds and Waltz 1996;McCafferty et al. 1997;Francischetti et al. 2001).
Adults can be distinguished by their small and undivided eyes, a median lighter mark (ommation) present on mesonotum, hind wings absent with anal area of fore wings expanded, and forceps 1-segmented.The subimagos emerge in the early morning in some species and at nightfall in others, molting within minutes; the adult stage is brief, lasting only a few hours at most (Edmunds et al. 1976;Domínguez et al. 2006;Da-Silva and Salles 2012).
The northern region of Brazil has 13 records of Caenidae species, mainly confined to small areas in Acre, Amazonas, and Pará (Puthz 1975;Malzacher 1986;1990;Angeli et al. 2016).Information regarding other states in the region remains virtually nonexistent.The state of Roraima occupies about 2.6% of Brazil (ITERAIMA 2005) and contains the largest continuous track of savannas in the Brazilian Amazon (Barbosa et al. 2005).The taxonomic knowledge of the Caenidae in the state of Roraima is unknown, with no records to this region until now.Here, we provide the first inventory of the family Caenidae for the state of Roraima.

MATERIALS AND METHODS
Collections were done between December 2015 and February 2016 in three sites in the state of Roraima (Figure 1).
The subimagos were captured with light traps from 18:00 until 05:40, and nymphs were captured with an aquatic entomological net.Male genital structures were examined in alcohol gel and then stored in alcohol.Nymphs were permanently mounted in Euparal.Identifications were based on keys in Domínguez et al. (2006) and also by comparisons against original descriptions.Diagnoses of each species are from Domínguez et al. (2006).
The material examined is housed in the Zoological Collection of Universidade de Roraima (UFRR), Boa Vista, Brazil.

Lists of species
Lima and Boldrini | First records of Caenidae from Roraima 3.1-3.5 mm; 2) base of antennal flagellum slender; 3) male genitalia with forceps enlarged near base and narrow toward apex, apex of forceps curved inwardly; 4) meso-and metanota light brown, abdomen yellowish with darker spots on terga II-III and VII.
Previous distribution.Brazil: states of Amazonas and Mato Grosso.Colombia: Leticia.

RESULTS
We provide below a list of new records of mayfly species to the state.For each species we list geographical distribution data and provide a diagnosis.

DISCUSSION
A total of 25 specimens and one exuvia belonging to three genera and five species were collected and recorded for the first time to state of Roraima.The nymphal exuvia of Latineosus was not possible to identify but probably represents a new species.Additional specimens are necessary to confirm its specific status.
Caenis chamie is known from all stages and appears to belong to the pflugfelderi-group of species as defined by Malzacher (2001) for C. pflugfelderi Malzacher, 1990 andC. panamensis Malzacher, 2001.This species shows some variation in the shape of male genitalia forceps, and is very similar to C. pflugfelderi Malzacher, 1990.However, it can be distinguished by having the apical margin of penes straight and the apophyses of the styliger sclerite pointed and straight.Caenis reissi, described from male imagos, belongs to the reissi-group Malzacher (1986Malzacher ( , 2001)), characterized by male genitalia with reduced, weak and uncoloured sclerites, often hardly recognizable.
Caenis fittkaui and B. irmleri, described from imagos of both sexes, nymphs and eggs in the original description (Irmleri 1975;Malzacher 1986), are characterized by male genitalia with strong, sclerotized, and apically pointed forceps.The presence of the last species represents the first record of the genus to the state of Roraima.