Tricorythopsis intercalatus, Belmont, Enide Luciana L., Salles, Frederico F. & Hamada, Neusa, 2011

Belmont, Enide Luciana L., Salles, Frederico F. & Hamada, Neusa, 2011, Three new species of Leptohyphidae (Insecta: Ephemeroptera) from Central Amazon, Brazil, Zootaxa 3047, pp. 43-53 : 50

Tricorythopsis intercalatus sp. nov.

( Figs. 22–29 )

Diagnosis. Tricorythopsis intercalatus can be distinguished from other species in the genus by the following combination of characteristics: nymph- 1) tarsal claws with 9 small marginal denticles intercalated by larger denticles and 4+3 submarginal denticles, with apical seta; 2) maxillary palp 1-segmented, short, as long as wide, with short, terminal seta; 3) undulations present on posterior margins of segments VI to VII; 4) black abdominal pigmentation with whitish areas in lateral margins of tergites.

Description. Nymph. Length: Body, 1.6–2.0 mm; Mesonotum, 0.6–1.0 mm; Caudal filaments, 1.4–1.8 mm. General coloration yellowish with black marks. Body robust, base of abdomen wider than apex ( Fig. 22 ). Head: yellowish without conspicuous marks. Mouthparts with coloration yellowish; labrum with a broad anteromedial emargination ( Fig. 23 ); maxilla yellowish with pectinate setae in inner margin; maxillary palp 1-segmented short, as long as wide, with short, terminal seta ( Fig. 25 ); glossa not fused, with flattened setae laterally fringed and bipectinate and paraglossa with many flattened setae laterally fringed ( Fig. 24 ). Thorax: yellowish with black marks. Tubercle absent on pronotum; anterolateral corner of pronotum not projected; pronotum yellowish with shaded black and white spots. Tubercle absent on mesonotum. Inner apical margin of forewing pads elevated. Legs yellowish with three black bands and black mark on coxa and femora; ratio of foreleg 1.5:1(0.3):1.4:3.3; coxal projections present only on foreleg ( Fig. 29 a); femura broad (as wide as broad) ( Fig. 29 a, 29b, 29c); outer margin of femur with medium size setae; transverse row of setae on anterior surface of femoa on submedian region ( Fig 23 ); tarsal claws with 9 small marginal denticles intercalated by larger denticles and 4+3 submarginal denticles, with apical seta ( Fig. 28 ). Abdomen: black abdominal pigmentation with whitish areas in lateral margins of tergites; undulations present on posterior margins of segments VI to VII; posterolateral margin expanded on segments III– VI, with segment VII forming a posterolateral projection barely discernible. Operculate gills ( Fig. 27 ) translucent with black mark above the transversal line; length of operculate gills reaching segment VII; gill formula 2/4/4/2/1. Caudal filaments yellowish.

Adults. Unknown

Biological aspects. Nymphs with a robust appearance were found among gravel in streams with bedrock and flow fast water.

Etymology. “ intercalatus ” Latim = intercalary. Referring to the denticles intercalary tarsal claws.

Discussion. Despite the similarity between the nymphs of Tricorythopsis intercalatus sp. nov. and T. pseudogibbus Dias & Salles, 2005 , the absence of anterolateral projections on the pronotum, tarsal claws denticulation (9 denticles intercalary with marginal denticles larger and 4+3 submarginal denticles), and a one-segmented maxillary palp, separates this new species from T. gibbus .

Material examined. Holotype: Nymph (in alcohol), Brazil, Amazonas, Presidente Figueiredo, AM-240, km 13 Cachoeira da Porteira (02°02'15"S /59°54'53W"), x-2009, Belmont, E.L.L., Cruz, P. V. and Boldrini, R. coll. ( INPA). Paratypes: 3 nymphs (in alcohol), same data as holotype, ( INPA); 2 nymphs (in alcohol), same data (CEUNES).

Figures

FIGURES 22 – 26. Tricorythopsis intercalatus sp. nov. 22. nymph; 23. labrum (left d. v. and right v. v.); 24. labium (left d. v. and right v. v.); 25. right maxilla, maxilary palp in detail; 26 a. left mandible (d. v.); 26 b. right mandible (d. v.).

FIGURES 27 – 29. Tricorythopsis intercalatus sp. nov. 27. right operculate gills (right d. v.); 28. anterior tarsal claw; 29 a. foreleg; 29 b. midleg; 29 c. hind leg.