A new species of Tricorythopsis Traver, 1958 (Ephemeroptera: Leptohyphidae) from Pará state, Brazil Author De Oliveira, Laura A. 0000-0001-5907-773X Laboratório de Ecologia e Taxonomia de Invertebrados Aquáticos, Universidade Federal do Oeste do Pará, CEP 68040 - 470, Santarém, PA, Brazil. & lauraalmeidaoliver @ gmail. com; https: // orcid. org / 0000 - 0001 - 5907 - 773 X lauraalmeidaoliver@gmail.com Author Do Nascimento, Jeane M. C. 0000-0001-8186-4203 Coordenação de Biodiversidade, Divisão de Curso de Entomologia, Instituto Nacional de Pesquisas da Amazônia, CEP 69067 - 375, Manaus, AM, Brazil. jeanemarcelle @ gmail. com; https: // orcid. org / 0000 - 0001 - 8186 - 4203 jeanemarcelle@gmail.com Author Couceiro, Sheyla R. M. 0000-0002-5428-7495 Laboratório de Ecologia e Taxonomia de Invertebrados Aquáticos, Universidade Federal do Oeste do Pará, CEP 68040 - 470, Santarém, PA, Brazil. & sheylacouceiro @ yahoo. com. br; https: // orcid. org / 0000 - 0002 - 5428 - 7495 sheylacouceiro@yahoo.com.br text Zootaxa 2021 2021-08-17 5023 1 131 141 journal article 4916 10.11646/zootaxa.5023.1.8 9d689439-3462-428f-b950-b0884e4189dd 1175-5326 5225581 80DA6665-6702-41DC-8C14-1AED9266D46C Tricorythopsis 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 . Mature nymph, Brazil , Pará state , Santarém , Ponte do Juá stream, 02°26’41”S ; 54°47’21”W ; 06.xii.2019 , Santos SE col. ( INPA-EPH 028 ) . PARATYPE . Nymph (parts on slide), Brazil , Pará , Mojuí dos Campos , Mojuí dos Caboclos stream , 02°42’03”S ; 54°41’01”W , 05.vii.2020 , Oliveira LA col. ( INPA-EPH 029 ) .