Tricorythodes tragoedia, Souto & Angeli & Salles, 2017, Souto & Angeli & Salles, 2017

Souto, Paula Malaquias, Angeli, Kamila Batista & Salles, Frederico Falcão, 2017, Tricorythodes tragoedia sp. nov. (Ephemeroptera: Leptohyphidae), a new species from Rio Doce and surrounding areas, southeastern Brazil, Zootaxa 4341 (4), pp. 554-562 : 555-560

TRIcORYThODES TRAgOEDIA sp. nov.

( Figures 1–18 )

Diagnosis. Tricorythodes tragoedia sp. nov. can be distinguished from other species of the genus by the following combination of characters. In the male imago: 1) tibiae with a large blackish mark on the subapical region; 2) abdomen shaded almost completely with black, but with small unpigmented dots ( Fig. 1 ); 3) penes broad and flattened ( Fig. 16 ); 4) forceps segment I subequal in length to segment II ( Fig. 16 ); 5) vein CuP present ( Fig. 15 ). In the nymph: 1) maxillary palp three-segmented with apical seta ( Fig. 8 ); 2) pronotum with pointed anterolateral projection ( Fig. 2 ); 3) legs with subapical blackish marks on femur and tibia, tarsi without marks ( Figs. 12–14 ); 4) dorsum of fore femur with a transversal row of setae on the submedian region ( Fig. 12 ); 5) middle femur with a transverse row of setae; 6) fore claw with 9–12 marginal denticles and one pair of submarginal denticles ( Fig. 9 ); 7) operculate gill triangular, yellowish with blackish diffuse marks ( Fig. 11 ); 8) lateral margins of abdominal segments III–VII expanded, segments VII–IX with posterolateral projections ( Fig. 2 ).

Descriptions. Male imago ( Figs 1 , 15, 16 ). Body, 3.4–3.8 mm; forewing, 3.8–4.1 mm; cerci= 7.5–10 mm; median terminal filament= 12.5–14 mm (n=6). General coloration: thorax brown, legs and abdomen whitish with blackish and brownish marks.

Head ( Fig. 1 ). Yellowish-brown, darker on hind margin and with Y-shaped black mark; black around bases of ocelli; antennae yellowish-white.

Thorax ( Figs 1 , 15 ). Pronotum yellowish-brown with blackish diffuse marks. Meso- and metanotum brown shaded with grey. Leg: coxa, trochanter and femur of foreleg dark brown; tibia with small subapical blackish mark; tarsus without marks; remaining segments of meso- and hind legs yellowish-white. Wing: membrane of forewing hyaline, longitudinal and cross veins whitish translucent, shaded with grey from costal margin to radial sector; vein CuP present.

Abdomen ( Figs 1 , 16 ). Terga yellowish-white, shaded with black. Sterna whitish shaded with black on lateral zones and near posterior margins. Genitalia: styliger plate yellowish-white, forceps white and penes yellowishtranslucent; penes broad and flattened; forceps segment I subequal to length of segment II. Caudal filaments white.

Female imago. Body, 3.1–4.1 mm; forewings, 3.4–5.0 mm; cerci= 9 mm; median terminal filament= 12.5 mm (n=6). General coloration as in male. Eggs in abdomen yellowish. Abdominal shading lighter than male. Caudal filaments whitish-translucent, cerci shorter and thinner than median terminal filament.

Nymph (last instar) ( Figs 2–11 , 17 ). Body, 4.4–5.8 mm; mesonotum, 1.1–1.6 mm; caudal filaments, 3.8–6.3 mm (n=12).

Head ( Figs 2–8, 10 ). Yellowish-white with blackish diffuse marks. Antennae yellowish-translucent. Mouthparts yellowish; maxillary palp three-segmented with apical seta.

Thorax ( Figs 2 , 9 , 12–14 ). General colouration yellowish or yellowish-white with blackish diffuse marks. Pronotum with short pointed anterolateral projection. Mesonotum yellowish with blackish diffuse marks, except in forewing pads, whitish or yellowish. Metanotum, pleurae and sterna yellowish with blackish marks. Legs narrow and long; colouration yellowish, dorsal regions of all femora with blackish marks; with large blackish mark on subapical region of each tibia; tarsus without marks; dorsum of fore femur and median femur with transverse row of setae on submedian region; femur subequal to tibia and 2× longer than tarsus and 3× longer than tarsal claw; width/length ratio of fore- and mid femur of 0.3; width/length ratio of hind femur of 0.25; fore claw with 9–12 marginal denticles and with pair of submarginal denticles; median and hind claws with 7–12 marginal denticles and with pair of submarginal denticles.

Abdomen ( Figs 2 , 11 ). General colouration yellowish with blackish diffuse marks. Sterna yellowish shaded with blackish marks, lateral regions of sterna III–VI shaded with grey. Lateral margins of abdominal segments III–VII expanded; segments VII–IX with posterolateral projections; segments II–VII with a posteromedial tuft of setae; segments VIII and IX with row of setae on posterior margin. Operculate gill triangular, yellowish with blackish areas; remaining gills whitish-translucent shaded with grey; gill formula 3/3/3/3/2; dorsal lamellae of gills 3–5 without basal flap; ventral lamellae of gills 3–5 subtriangular without dorsal projection. Caudal filaments ranging from yellowish-white to light brown.

Variation. Some adult specimens from the same population showed darker coloration, with the abdomen almost completely shaded with black. Other specimens showed a black longitudinal dorsal stripe. Some other specimens showed tibiae with orange bands.

Two nymphs showed lighter coloration, with blackish markings forming a darker rounded spot in the middle of the operculate gill. Some specimens had orange diffuse marks on the operculate gills.

Life cycle association. Adults of both sexes and nymphs from close or the same localities were associated by shared color patterns. Two female adults were reared from nymphs to confirm these associations.

Type material. Brazil, Espírito Santo State: HOLOTYPE: São Mateus, Rio Preto, tributary of Rio São Mateus, S18°44'8'', W39°47'47'', 12.xii.2008, Massariol, F.C. & Angeli, K.B. leg., male nymph (CZNC Ep-7022). PARATYPES: Same data as holotype, 3 nymphs (CZNC Ep-669, legs, operculate gill and mouthparts of one nymph on slide); same data as holotype, 2 nymphs (IBN); São Mateus, Fazenda Liberdade, Rio Cricaré, tributary of Rio São Mateus, S18°39'2'', W40°7'23'', 22-23.v.2012, Salles, F.F. leg, 1 male subimago (CZNC Ep-6163, genitalia and wing on slide); São Mateus, Rio Cotaxé, tributary of Rio São Mateus, S18°37'41'', W40°6'41.6'', 20- 21.xi.2012, Salles, F.F. leg., 3 male imago (CZNC Ep-6200,genitalia and wing of one imago on slide); same locality, 5-6.ii.2013, Salles, F.F. leg., 2 male subimagos (CZNC Ep-6180); Sooretama, Rio São José, tributary of Rio São Mateus, S19°7'33'', W40°14'26'', 21.ii.2013, Salles, F.F. leg., 1 nymph (CZNC Ep-5387, legs, operculate gill and mouthparts on slide); same locality, 09.ix.2010, Salles, F.F. leg., 2 nymphs (CZNC Ep-1392); same locality, 04.xi.2013, Salles, F.F. leg., 1 nymph (CZNC Ep-5533); same data, 1 nymph (IBN); Sooretama, Reserva Biológica de Sooretama, Cachoeira Bonjardim, S18°59'56'', W40°14'01'', 29.iv.2009, Salles, F.F. leg., 1 nymph (CZNC Ep-1139); Sooretama, Reserva Biológica de Sooretama, Córrego Rodrigues, S19°01'36'', W40°13'39'', 30.iv.2009, Salles, F.F. leg, 1 nymph (CZNC Ep-1173); Nova Venécia, Santa Rita do Pip-Nuk, Rio Cricaré, tributary of Rio São Mateus, S18°39'51'', W40°30'45'', 22.x.2012, Salles, F.F. leg., 2 nymphs (CZNC Ep-5473, legs, operculate gill and mouthparts of one nymph on slide); same locality, 25-26.vii.2012, Salles, F.F. leg., 1 female imago (CZNC Ep-4543); same locality, 22.x.2011, Salles, F.F. leg., 2 female imagos reared from nymph (CZNC Ep-7004); Nova Venécia, Rio Cricaré, tributary of Rio São Mateus, S18°42'55'', W40°22'33'', 21- 22.xi.2012, Salles, F.F. leg., 1 male imago (CZNC Ep-6195, genitalia and wing on slide); same locality, 18- 19.ii.2013, Salles, F.F. leg., 4 male imagos (CZNC Ep-6170); Nova Venécia, Patrimônio do Bis, Rio Cotaxé, tributary of Rio São Mateus, S18°33'27'', W40°20'6'', 20-21.xi.2012, Salles, F.F. leg., 2 female imagos and 2 male imagos (CZNC Ep-6160); same locality, 16-17.iv.2012, Salles, F.F. leg., 2 male subimagos and 1 female subimago (IBN); Pinheiros, Reserva Biológica do Córrego do Veado, Córrego São Roque, S18°19'26'', W40°07'34'', 25.ii.2010, Salles, F.F. leg., 1 nymph (CZNC Ep-1721); Colatina, Itapina , Rio Doce, S19°31'18'', W 40°50'11'', 11.ix.2014, Salles, F.F. leg., 1 nymph (CZNC Ep-7010) Same data, 2 nymphs (CZNC Ep-6999, legs, operculate gill and mouthparts of one nymph on slide); same data, 1 nymph (CZNC Ep-7000, legs, operculate gill and mouthparts on slide); same data, 2 nymphs (CZNC Ep-7001, legs, operculate gill and mouthparts on slide); same data, 1 nymph (CZNC Ep-7002, legs, operculate gill and mouthparts on slide); same data as holotype, 2 nymphs (CZNC Ep-7003); same data, 1 nymph (IBN); Colatina, Ipiranga , Rio Doce, S19°59'23'', W40°16'41'', 19-20.xi.2014, Salles, F.F. leg. (CZNC Ep-7012); Colatina, Baunilha , Rio Doce, S19°30'53'', W40°30'59'', 19-20.xi.2014, Salles, F.F. leg., 1 male imago (CZNC Ep-6459, genitalia and wing on slide); Linhares, Fazenda Rio Claro, Rio Doce, S19°32'18'', W39°52'59, 24.ix.2014, Salles, F.F. leg., 1 male imago (CZNC Ep-7011, genitalia and wing on slide); same data, 1 male imago (IBN); Linhares, Instituto Federal do Espírito Santo, Rio Doce, S19°26'39'', W39°57'00'', 23-24.ix.2014, Salles, F.F. leg., 1 male subimago (CZNC Ep-6513); Linhares, Fazenda Amparo, Rio Doce, S19°26'51'', W39°56'29'', 23-24.ix.2014, Salles, F.F. leg., 1 male imago (CZNC Ep-6520); same data, 1 male imago (IBN).

Biology. Tricorythodes tragoedia sp. nov. was found in a variety of habitats in the northern portion of the State of Espírito Santo. This area is completely within the Atlantic Forest biome, but only a few, and usually small, remnants of the original vegetation can be found. Our specimens were collected from a range of small streams to large rivers, but they always were collected at low altitudes of less than 100 meters ( Fig. 18 ). Nymphs inhabit submersed substrates such as leaves, pool litter, macrophytes, marginal vegetation, roots, and algae in areas with slow current. Nymphs and adults were found throughout the year.

Most of the sampling sites are under the influence of agriculture and/or cattle, and do not present wellpreserved riparian vegetation. On the other hand, a few of the collected areas are inside federal conservation units, such as Reserva Biológica de Sooretama and Reserva Biológica do Córrego do Veado, and their original riparian vegetation is well-preserved even though the headwaters of these streams are often outside the conservation units, where they are subjected to the same impacts from cattle and other agricultural practices. On top of that, the habitat alterations caused by the recent environmental tragedy of the dam break on the Doce River ( Fernandes et al. 2016) is a possible threat to populations of this new species and its habitats.

Distribution ( Fig 18 ). Southeastern Brazil, Espírito Santo State ( Colatina, Ipiranga, Linhares , Nova Venécia, São Mateus, Sooretama, Pinheiros).

Etymology. The specific epithet, tragoedia , is from Latin and means "tragedy", in reference to the social and environmental disaster caused by the rupture in November 2015 of a mining dam controlled by Samarco Mineração S.A., a joint venture between mining BHP Billiton and Vale S.A. in the Doce River, were some of the paratypes were collected.

Figures

FIGURE 17. Tricorythodes tragoedia sp. nov., mature nymph. Photo by Frederico F. Salles.

FIGURE 18. Physiographic map of Espírito Santo State showing the main rivers with details of the distribution of the new species according to the altitude, showing that the new species is restricted to low altitudes (less than 100 m).

FIGURES 1 – 2. Tricorythodes tragoedia sp. nov., habitus: (1) male imago, paratype, dorsal view; (2) mature nymph, paratype, dorsal view.

FIGURES 3 – 11. Tricorythodes tragoedia sp. nov., mature nymphs, paratypes: (3) left mandible, dorsal view; (4) labrum, dorsal view; (5) right mandible, dorsal view; 6: hypopharynx, ventral view; (7) right maxilla, dorsal view; (8) detail of maxillary palp; (9) tarsal claw of fore leg, dorsal view (arrow indicates the submarginal denticle); (10) labium, ventral view; (11) gill II, dorsal view.

FIGURES 12 – 14. Tricorythodes tragoedia sp. nov., mature nymph, paratype: (12) fore leg, dorsal view; (13) middle leg, dorsal view; (14) hind leg, dorsal view.

FIGURES 15 – 16. Tricorythodes tragoedia sp. nov., male imago, paratype: (15) fore wing, dorsal view; (16) genitalia, ventral view.