Baetodes santatereza Salles & Polegatto

Salles, Frederico Falcão & Polegatto, Cleber Macedo, 2008, Two new species of Baetodes Needham & Murphy (Ephemeroptera: Baetidae) from Brazil, Zootaxa 1851, pp. 43-50 : 44-46

Baetodes santatereza Salles & Polegatto , n. sp.

( Figs. 1 – 13 )

Nymph. Body length: 2.75mm; cerci: 3.3mm; terminal filament: 0.3mm. General coloration brownish.

Head. Coloration brownish, with whitish area between ocelli and compound eyes, and a whitish longitudinal band between median ocelus and anterior margin of head. Compound eyes black; turbinate portion orange brown. Antennae light brown. Labrum ( Fig. 2 ) not expanded laterally, dorsal surface of each side of midline with a row of six setae; four setae near midline, alternating one long, one short, and two long setae near lateral margin. Hypopharynx as in Figure 3 , apex of lingua broadly pointed. Mandibles as in Figs. 4 – 5 . Maxillae ( Fig. 6 ) medially with three setae. Labium ( Fig. 7 ), with glossae shorter than paraglossae, and with two bladelike setae, the medial nonpectinate and the lateral pectinate, and five fine setae in lateral margin; paraglossae with one slightly pectinate hard seta among various fine pectinate setae.

Thorax. Coloration brownish; pronotum eventually with dark longitudinal bands on lateral margins and along midline; pleura and sterna yellowish white. Pronotum with posterior margin slightly elevated ( Fig. 13 ). Metanotum with tubercle ( Fig. 13 ). Legs ( Figs. 1 , 8 – 9 ) light brown with whitish spot at the base and apex of all femora; dorsal edge of femora with five to seven clavate setae, nearly one half the length of long, fine setae ( Figs. 8, 9 ). Tarsal claws ( Fig. 10 ) with six to seven denticles, the basal three denticles small and truncate, the apical three or four denticles pointed and increasing in length. One gill on each coxa ( Fig. 8 ).

Abdomen. Coloration dark brown ( Fig. 1 ), except terga 10 light brown; terga 6 – 9 with brown spot near midline; sterna yellowish white, with lateral margins of segments 1 – 9 suffused with brown. Segments 1 – 9 with median blunt dorsal tubercle, and fine long setae ( Figs. 11, 13 ); posterior ¼ of terga covered with minute spines ( Fig. 11 ). Gills oblong, whitish translucent with tracheation weakly pigmented ( Fig. 12 ). Caudal filaments yellowish white.

Adults: unknown

Etymology: after Santa Tereza, former name of the Ecological Station where the new species was found.

Material examined: Holotype. Male nymph. Brazil, São Paulo State, Ribeirão Preto, Ecological Station of Ribeirão Preto-Santa Tereza Forest (STF), Boa Vista Stream, 01.X.2004, C.M. Polegatto, Cristina Perin, Diego Barione, Camila M. Silva, Jeanne M. J. Amaral. Paratypes. 10 nymphs, same data as holotype, except two nymphs collected in 04.X.2004.

Diagnosis: Baetodes santatereza , n. sp., can be distinguished from the other known species of the genus by the following combination of characters: 1) small body size; 2) glossae with two bladelike setae, the medial nonpectinate and the lateral pectinate, paraglossa without nonpectinate blade-like ( Fig. 7 a,b); 3) dorsal edge of femora with five to seven clavate setae, nearly one half the length of long, fine setae ( Fig. 8 – 9 ); 4) one gill on each coxae ( Fig. 8 ); 5) metanotum and abdominal segments 1 – 9 with dorsal tubercles ( Fig. 13 ).

Biology: Nymphs of B. santatereza , n. sp., were collected in Ribeirão Preto, State of São Paulo, in a third order stream in an Atlantic forest fragment, the Ecological Station of Ribeirão Preto - Santa Tereza Forest (STF). They were found living in small rapids provided by stones with ca. 50 cm, although some nymphs were also found inhabiting deep stones in riffle areas. In rapids the nymphs were more abundant at the end of the rainy season to the beginning of the dry/cold months, decreasing in the following months. The following measures were taken during the samples: water temperature 20.3o C in July to 22.4o in the first warm months; pH is 6.2 – 6.9.

The STF is located in a large agricultural area, with sugarcane as the chief crop, where most of the forests were destroyed in the last decades. Although the canopy is abundant over the stream, depositional material is common due the reduction or absence of parts of the riparian vegetation. Integral protection of the STF still depends on Brazilian and regional laws.

Figures

FIGURE 1. Baetodes santatereza, n. sp.; General habitus of nymph.

FIGURES 2 – 13. Baetodes santatereza, n. sp., nymph; 2, labrum. 3, hypopharynx. 4, left mandible. 5, right mandible. 6, maxilla. 7, labium (a, left, dorsal view, right, ventral view; b, detail of glossa; c, detail of segment 3 of palp). 8, foreleg. 9, detail of dorsal edge of femora. 10, tarsal claw. 11, tergum 4. 12, gill. 13, lateral view of nymph.