A new species of Tricorythopsis Traver, 1958 (Ephemeroptera: Leptohyphidae) from Pará state, Brazil De Oliveira, Laura A. Do Nascimento, Jeane M. C. Couceiro, Sheyla R. M. Zootaxa 2021 2021-08-17 5023 1 131 141 De Oliveira & Do Nascimento & Couceiro, 2021 De Oliveira & Do Nascimento & Couceiro 2021 [151,410,860,887] Insecta Leptohyphidae Tricorythopsis Animalia Ephemeroptera 1 132 Arthropoda species similis sp. nov.  ( Figs 2–5)   Diagnosis.Nymph: 1) maxillary palp 1-segmented ( Fig. 4E); 2) segment II of labial palpi shorter than segment I and longer than segment III ( Fig. 4F); 3) femora and tibiae with margins covered by long and pectinate setae ( Figs 5A–D); 4) tarsal claws with 4 to 5 marginal denticles and 4+2 very small, submarginal denticles ( Fig. 5E); 5) abdominal terga III–VII with acute, serrated tubercles medially located on posterior margins ( Figs 2A–C, 3C); 6) transversal line of operculate gill absent ( Fig. 3D).  Mature nymph. Length: body, 2.3 mm; antenna, 0.7 mm; mesonotum, 0.8 mm; caudal filaments broken. Body robust, base of the abdomen wider than the apex ( Fig. 2A). General coloration yellowish brown, with blackish and purplish marks irregularly distributed. Head. Yellowish brown, with few, blackish marks irregularly distributed. Tubercles absent. Eyes and ocelli blackish ( Figs 2A–B; 3A). Antennae: scape and pedicel whitish yellow, flagellomeres grayish translucent on basal half and whitish translucent on distal half. Mouthparts yellowish translucent ( Figs 3B; 4A–G). Labrum broad, with shallow anteromedial emargination; with pores distributed on basal 1/4 ( Fig. 4A). Hypopharynx as in Figure 4B. Mandible: basal half with purplish marks irregularly distributed; incisors and molars dark brown ( Figs 4C–D); basal 3/5 with spaced pores. Maxilla with pectinate setae at the apex; palp 1-segmented, approximately 2.5 times longer than wide, with a terminal seta ( Fig. 4E). Labium with spaced pores; glossa not fused, with filiform setae; paraglossa with filiform setae; segment II of labial palp shorter than segment I and longer than segment III ( Fig. 4F); lateral margin of submentum with short, filiform setae ( Fig. 4F). Thorax. Yellowish brown, with blackish marks irregularly distributed and with purplish marks near medial line ( Figs 2A–B; 3A). Pronotum without tubercles; anterolateral corner projected and rounded ( Fig. 3A). Mesonotum with a pair of small anterolateral tubercles; with a pair of slightly developed submedial humps near apex of forewing pads ( Fig. 3A). Developing wings with dark gray veins; internal margin blackish basally. Legs. General coloration yellowish white, with purplish and grayish marks; dorsal surface of femora with circular, whitish marks irregularly distributed ( Figs 5A–D). Coxae projections absent. Femora almost 1.5 times longer than wide. Femora and tibiae with margins covered by long and pectinate setae. Fore femur with a transversal row of long, pectinate setae on submedial region of the dorsal surface. Tarsal claws ( Fig. 5E) almost entirely yellowish white, except by apical region yellowish brown; with 4 to 5 marginal denticles and 4+2 very small, submarginal denticles; with apical seta. Abdomen. Terga yellowish brown, with blackish marks; segments VII–IX with a paired sublateral, transversal, blackish strip ( Figs 2A–C; 3C). Sterna whitish yellow. Segments III–IX with lateral margins expanded; segments VI–IX with posterolateral projections bordered with thin setae (projection less developed on segment VI) ( Figs 2C; 3C). Terga III–VII with acute, serrated tubercles medially located on posterior margins; tubercle slightly shorter on tergum III ( Figs 2A–C; 3C). Gills. Operculate gills yellowish brown, with purplish or grayish marks; oval, almost 1.4 times longer than wide; reaching the segment VII ( Figs 2A–C; 3C–D). Ventral lamellae without fringed lobes, without ridges. Transversal line of operculate gill absent. Caudal filaments yellowish brown, with short setae at segment joints.   FIGURE 1.Location of the study area. A, Map of Brazil with highlighted area containing the Pará state; B, Pará state with the location of the sampled sites; C, Santarém and Mojuí dos Campos municipalities, in detail, indicating the sites sampled for  Tricorythopsis similis  sp. nov.( Ephemeroptera: Leptohyphidae); D, Santarém municipality, Ponte do Juá stream; E, Mojuí dos Campos municipality, Mojuí dos Caboclos stream.   FIGURE 2.  Tricorythopsis similis  sp. nov., mature nymph. A, Dorsal view; B, Lateral view; C, Partial region of abdomen, lateral view, with dorsal tubercles in detail.   FIGURE 3.  Tricorythopsis similis  sp. nov., mature nymph. A, Head and thorax, dorsal view; B, Head, ventral view, anterior region in detail showing setae covered by sediments; C, Abdomen, dorsal view; D, Operculate gill.  Adults.Unknown   Etymology.The specific epithet is a Latin word meaning alike. It is in reference to the general similarity of this species and  T. rondoniensis.  Habitat.Nymphs of  Tricorythopsis similis  sp. nov.were collected in two slow-flowing rivers (with width varying to 6–12 m) and associated to marginal vegetation in sections exposed to sunlight ( Figs 1D–E).   Material examined.  HOLOTYPE. Maturenymph, Brazil, Pará state, Santarém, Ponte do Juástream, 02°26’41”S; 54°47’21”W;  06.xii.2019, Santos SEcol. ( INPA-EPH 028).  PARATYPE. Nymph(parts on slide), Brazil, Pará, Mojuí dos Campos, Mojuí dos Caboclosstream,  02°42’03”S; 54°41’01”W,  05.vii.2020, Oliveira LAcol. ( INPA-EPH 029). 3336456301 2019-12-06 INPA-EPH Santos SE Brazil Mature -2.4447222 Ponte do Jua 21 -54.789165 Santarem 4 135 INPA-EPH 028 1 Para holotype 3336456303 Mojui dos Campos & Mojui dos Caboclos Brazil Nymph 4 135 1 Para paratype 3336456302 2020-07-05 INPA-EPH Oliveira LA Brazil -2.7008333 21 -54.683613 4 135 INPA-EPH 029 1 Para paratype