Contribuição para o conhecimento do gênero Chironomus Meigen, 1803 na região neotropical.

The present work aimed to study one of the most used genera in water quality assessment, Chironomus, identifying and/or describing the species inhabiting aquatic systems of the State of São Paulo with varied ecological features. The study area included 27 aquatic systems consisting of lentic habitats (lakes, reservoirs, temporary pools, waste stabilization lagoons and fish ponds) and lotic habitats (streams, rivers and drainage channels) at different localities of Mogi-Guaçu and Tietê-Jacaré hydrographic sub-basins. The sampling and analyses followed the conventional methods used in taxonomic and limnological studies. The survey resulted in the identification of 16 Chironomus species, including 7 new records to the State of São Paulo and 8 new species. Besides C. sancticaroli Strixino & Strixino, 1981, a species previously recorded in the State of São Paulo, I identified the immatures and adults of C. calligraphus Goeldi, 1905, C. gigas Reiss, 1974, C. latistylus Reiss, 1974, C. paragigas Reiss, 1974, C. strenzkei Fittkau, 1968, C. stigmaterus Say, 1823 and C. columbiensis Wülker et al., 1989. Some species were sampled in similar habitats, indicating a possible relation with them. C. gigas, C. paragigas and C. latistylus were collected only in lentic systems with low antropic influence. The immatures of C. sp. 1, C. sp. 5 and C. sp. 6 were sampled only in association with aquatic macrophytes growing in lakes and stream pools. C. sp. 3 and C. sp. 4 inhabited temporary pools with great amounts of detritus. C. stigmaterus and C. calligraphus were found only in waste stabilization lagoons. Only the larvae of C. sp. 2 were sampled in lotic systems polluted with high level of organic material from urban sewage and agricultural activities. The morphological analyses of larvae enabled the construction of a preliminary identification key for the species of Chironomus that live in the different aquatic systems of the State of São Paulo. This key could be a useful tool in analyses and diagnostics carried out during water quality assessment programs.Universidade Federal de Minas GeraisO objetivo deste trabalho foi estudar um dos gêneros mais utilizados em avaliações da qualidade da água, Chironomus, identificando e/ou descrevendo as espécies existentes em ambientes aquáticos do Estado de São Paulo com diferentes características ecológicas. A área de estudo compreendeu 27 sistemas incluindo ambientes lênticos (lagoas, represas, poças temporárias, lagoas de estabilização, viveiros) e lóticos (córregos, rios e canais de drenagem) de diferentes localidades das sub-bacias hidrográficas Mogi-Guaçu e Tietê-Jacaré. As coletas e análises seguiram a metodologia convencional para estudos limnológicos e taxonômicos. Nos sistemas analisados foram identificadas 16 espécies de Chironomus, das quais 7 são novos registros para o Estado de São Paulo e 8 são novas espécies. Além de C. sancticaroli Strixino & Strixino, 1981, espécie já registrada no estado de São Paulo, foram identificados imaturos e adultos de C. calligraphus Goeldi, 1905, C. gigas Reiss, 1974, C. latistylus Reiss, 1974, C. paragigas Reiss, 1974, C. strenzkei Fittkau, 1968, C. stigmaterus Say, 1823 e C. columbiensis Wülker et al., 1989. Algumas espécies foram amostradas em ambientes com características semelhantes, apontando uma possível relação com aqueles sistemas. C. gigas, C. paragigas e C. latistylus foram coletadas apenas em ambientes lênticos com reduzidos impactos antrópicos. Os imaturos de C. sp. 1, C. sp. 5 e C. sp. 6 foram obtidos apenas junto a macrófitas aquáticas que se desenvolvem em lagoas ou em remansos de córregos. C. sp. 3 e C. sp. 4 estiveram presentes em águas temporárias com grande quantidade de detritos vegetais. C. stigmaterus e C. calligraphus só foram amostrados em lagoas de estabilização. As larvas de C. sp. 2 foram as únicas amostradas em vários sistemas lóticos que recebem elevadas cargas orgânicas provenientes de esgoto urbano e de atividades agrícolas. A análise morfológica das larvas possibilitou a construção de uma chave preliminar de identificação das espécies do gênero que vivem nos diferentes sistemas aquáticos do Estado de São Paulo. Esta poderá servir como ferramenta para as análises e diagnósticos realizados em programas de avaliação da qualidade da água

Chironomus oliveirai Correia & Trivinho-Strixino, 2007, sp. n.

Chironomus oliveirai sp. n. (Figs. 6, 10, 18, 19, 27, 28, 47–52) Type material. Holotype male. BRAZIL: São Paulo, Pirassununga, Nova Reservoir (Centro de Pesquisa e Treinamento em Aqüicultura - CEPTA / IBAMA), 18.iii. 2002, L. Correia (LEA). Paratypes: 2 males, 1 gynandromorphic female with pupal and larval exuviae, 7 larvae, as holotype (LEA, MZUSP). Etymology. Named in honor of the late Dr. Sebastião José de Oliveira, for his contributions to the knowledge of Neotropical Chironomidae. Diagnostic characters. The male can be distinguished from other Neotropical Chironomus species by the following combination of characters: legs yellowish brown with tarsi, tibia and distal third of femur of foreleg dark brown, and tarsi, tibia and apex of femur of mid- and hind legs brown; abdomen pale brown with brownish posterior markings on tergites I–VI; and superior volsella comparatively stout, strongly curved. The pupa differs from other described pupae of Neotropical species by having strong spines near posterior margin of tergites IV–VI. The larva can be distinguished from other Neotropical species by the following combination of characters: postmentum with dark spot; antennal blade not surpassing segment four; premandible with 4 dark teeth; mandible with three inner teeth; mentum with trifid, slightly incised median tooth; and abdomen without lateral tubules, with 2 pairs of comparatively long ventral tubules which is slender in distal half. Male (n = 3) Length [5.5] 5.5 –6.0 mm. Coloration: head yellowish brown, flagellum and maxillary palp pale brown. Thorax yellowish brown with brown mesonotal stripes. Sternum yellowish brown; scutellum yellowish; postnotum brownish, darkened in posterior portion (as in Fig. 2). Abdomen (Fig. 6), pale brown; tergites I–VI with posterior brownish markings; tergites I and VI paler than tergites II–V. Legs (Fig. 10), yellowish brown; tarsi, tibia and distal 1 / 3 of femur of foreleg dark brown; apex of femur, tibia and tarsi of mid- and hind legs brown. Head. Flagellum [1265] 1247–1281 µm long; AR = [3.04] 3.04–3.26. Palpomere 2–5 lengths (in µm): [40] 40–49, [201] 176–201, [204] 185–207, [302] 299–321. Frontal tubercles 15 µm long, about 2 times as long as wide. Dorsal and ventral interocular distance [123] 114–123 µm and [198] 191–198 µm, respectively. Temporal setae [28] 26–32. Clypeus with [16] 16–17 setae. Thorax. Acrostichals [9] 8–11, biserial, beginning near antepronotum; dorsocentrals [10] 6–10, partly biserial; prealars 5; supraalar 1. Scutellum with 12 uniserial, transversally arranged setae. Scutal tubercle low. Wing. Length [2.85] 2.70–2.85 mm. Membrane transparent, without setae; most veins pale brown; RM brown, darker than FCu. Brachiolum with [3] 2–3 setae, R with [37] 37–38 setae, R 1 with [27] 27–32 setae, R 4 + 5 with [31] 31–38 setae in distal 2 / 3. Squama with [9] 7–9 setae. R 2 + 3 ends halfway between R 1 and R 4 + 5. VR = [1.08] 1.06–1.08. Legs. Mid- and hind ta 1 with [7] 7–8 and [7] 7–9 sensilla chaetica, respectively. Lengths and proportions of legs as in Table 4. Hypopygium (Fig. 18). Anal tergal bands fully enclosing [15] 15 strong setae. Anal point with narrow base, apex curved ventrad. Superior volsella (Figs. 18, 19), stout, strongly curved ventromedially; basal lobe with [8] 7–8 long setae. Inferior volsella weakly clubbed, not extending beyond mid-point of gonostylus. Gonostylus elongate, [185] 185–191 µm long; distal part slender, with [5] 5–6 inner marginal setae. Pupa (n = 1) Length of abdomen 5.2 mm. Exuviae pale brown. Cephalothorax. Cephalic tubercles conical, frontal setae 48 µm long. Thorax granulose in anteromedian dorsal region; scutal tubercle present; lateral antepronotals 2, precorneals 2, dorsocentrals 4. Dc 1 and Dc2, 3, 4 as in Figure 24. Abdomen (Fig. 27). Tergites IV–VI with strong spines near posterior margin, T VI with shagreen near anterior margin, T VII with pair of lateral patches of shagreen near anterior margin, T VIII with pair of median patches of shagreen near posterior margin. Conjunctives IV/V and V/VI with fine shagreenation. Hook row continuous, occupying 1 / 2 width of segment II. Pedes spurii B present on segment II. Pedes spurii A present on segment IV. Spur on segment VIII with 1 tooth (Fig. 28). Segments I–IV with 0, 3, 3, 3 L setae; segments V–VIII with 4, 4, 4, 5 taeniae, respectively. Anal lobe with 1 stout dorsal seta and about 148 taeniate fringe setae. 4 th instar larva (n = 8) Total length 10.0-12.0, 11.0 mm. Coloration: body red; head yellowish, postmentum (Fig. 47), with dark spot. Head. Ventral head length 262–290, 273 µm; head width 463–540, 499 µm. Antenna (Fig. 48), 165–201, 187 µm long; AR = 1.30–1.65, 1.46; ring organ near base; antennal blade not surpassing mid of segment four. Pecten epipharyngis (Fig. 49), simple, consisting of about 14 subequal teeth. Premandible (Fig. 50), with 4 dark teeth and well-developed brush. SI (Fig. 51), plumose. Mandible (as in Fig. 40), with yellowish brown dorsal tooth; apical and three inner teeth blackish; inner margin with 2–3 spines. Mentum (Fig. 52), with slightly incised, trifid median tooth; and 6 pairs of blackish, lateral teeth. Ventromental plates separated by about 1 / 4 width of mentum, anterior margin smooth. Abdomen. Anal tubules with median constriction; without lateral tubules; with 2 pairs of ventral tubules, 0.9–1.1, 1.0 mm long, slender in distal 1 / 2. Remarks. Chironomus oliveirai does not seem to be closely related to any other described Neotropical Chironomus species. The distinct superior volsella combined with the coloration of the legs and abdominal tergites will separate the male of C. oliveirai. In the pupa C. phytophilus is the most similar Neotropical species, but the pupa of C. oliveirai has strong spines near posterior margin of tergites IV–VI and a pair of lateral patches of shagreen near anterior margin of tergite VII, while C. phytophilus has strong spines near posterior margin of tergites V–VI and one single patch of fine shagreenation near anterior margin of tergite VII. In the larva C. phytophilus and Chironomus sp. AR 4 (Reiss 1974) are the most similar Neotropical species. However, the larvae of C. oliveirai can be distinguished by the following combination of characters: postmentum with dark spot; mentum with slightly incised, trifid median tooth, which is more incised in Chironomus sp. AR 4; antennal blade not surpassing segment four, while it is surpassing segment five in C. phytophilus; and abdomen with 2 pairs of ventral tubules which is slender in distal half, while they are not slender in distal half in C. phytophilus. Ecology. Larvae of Chironomus oliveirai were collected from sandy sediments in two reservoirs, Represa Nova and Represa Velha, at the fishing farm station of CEPTA / IBAMA in Pirassununga, São Paulo.Published as part of Correia, Leny Célia Da Silva & Trivinho-Strixino, Susana, 2007, New species of Chironomus Meigen (Diptera: Chironomidae: Chironominae) from Brazil, pp. 53-68 in Zootaxa 1504 on pages 63-65, DOI: 10.5281/zenodo.17715

Chironomus antonioi Correia & Trivinho-Strixino, 2007, sp. n.

Chironomus antonioi sp. n. (Figs. 1, 4, 8, 14, 15, 23, 36–41) Type material. Holotype male with pupal and larval exuviae. BRAZIL: São Paulo, Luiz Antônio, Boa Sorte Stream, 18.vii. 2001, L. Correia (LEA). Paratypes: 4 larvae, as holotype (LEA). Etymology. Named after its type locality, the small town of Luiz Antônio. Diagnostic characters. The male can be distinguished from other Neotropical Chironomus species on the dark brown foreleg; yellowish brown mid- and hind legs with tarsi, tibia and distal third of femur dark brown; and the yellowish brown abdomen with pale brown markings on tergites I–VI. The pupa is indistinguishable from most described Neotropical species. The larva can be distinguished from other Neotropical species by the following combination of characters: abdomen with rather long lateral and ventral tubules, postmentum and frontoclypeus without pigmentation, mentum with slightly incised trifid median tooth and fourth lateral tooth smaller than fifth lateral tooth, and mandible with three inner teeth. TABLE 1. Lengths (in µm) and proportions of legs of Chironomus detriticola sp. n., male (n = 4) Male (n = 1) Length 3.9 mm. Coloration: head yellowish brown, flagellum and maxillary palp pale brown. Thorax (Fig. 1), yellowish brown with brown mesonotal stripes and median region darkened. Sternum yellowish brown; scutellum yellowish; postnotum brownish, darkened in posterior portion. Abdomen (Fig. 4), yellowish brown; tergites I–VI with pale brown markings. Legs (Fig. 8), yellowish brown; foreleg dark brown; mid- and hind legs with distal third of femur, tibia, and tarsi dark brown. Head. Flagellum 827 µm long; AR = 3.23. Palpomere 2–5 lengths (in µm): 25, 80, 96, 136. Frontal tubercles 20 µm long, about 3 times as long as wide. Dorsal and ventral interocular distance 62 and 179 µm, respectively. Temporal setae 27. Clypeus with 13 setae. Thorax. Acrostichals 8, biserial, beginning near antepronotum; dorsocentrals 6, partly biserial; prealars 4; supraalar 1. Scutellum with 5 uniserial, transversally arranged setae. Scutal tubercle low. Wing. Length 1.77 mm. Membrane transparent, without setae; most veins pale brown; RM brown, darker than FCu. Brachiolum with 2 setae, R with 20 setae, R 1 with 16 setae, R 4 + 5 with 19 setae in distal 2 / 3. Squama with 9 setae. R 2 + 3 ends halfway between R 1 and R 4 + 5. VR = 1.05. Legs. Mid- and hind ta 1 with 9 and 8 sensilla chaetica, respectively. Lengths and proportions of legs as in Table 2. Hypopygium (Fig. 14). Anal tergal bands fully enclosing 9 strong setae. Anal point parallel-sided. Superior volsella (Figs. 14, 15), narrow, straight; basal lobe with 8 long setae. Inferior volsella elongate, extending slightly beyond mid-point of gonostylus. Gonostylus strongly inflated, abruptly tapered apically, 137 µm long, with 6 inner marginal setae. Pupa (n = 1) Length of abdomen 3.4 mm. Exuviae pale brown. Cephalothorax. Cephalic tubercles conical, frontal setae 20 µm long. Thorax granulose in anteromedian dorsal region; scutal tubercle present; lateral antepronotals 2, precorneals 2, dorsocentrals 4. Abdomen. Tergite VI with small posterior patch of shagreen points; T VI–VII with fine shagreenation near anterior margin; T VIII with pair of posteromedian patches of fine shagreen; T V–VI with posterolateral point patches. Conjunctives IV/V and V/VI with fine shagreenation. Hook row continuous, occupying 2 / 3 width of segment II. Pedes spurii B present on segment II. Pedes spurii A present on segment IV. Spur on segment VIII with 1 apical and 1 short lateral tooth (Fig. 23). Segments I–IV with 0, 3, 3, 3 L setae; segments V–VIII with 4 taeniae. Anal lobe with 1 stout dorsal seta and about 78 taeniate fringe setae. 4 th instar larva (n = 5) Total length 8.0–9.0, 8.6 mm. Coloration: body red; head yellowish, postmentum and frontoclypeus without dark areas. Head. Ventral head length [248] 212–248, 238 µm; head width [488] 410–488, 443 µm. Antenna (Fig. 36), [246] 189–246, 219 µm long; AR = [1.57] 1.45–1.57, 1.49; ring organ near base; antennal blade surpassing segment three. Pecten epipharyngis (Fig. 37), simple, consisting of about 16 subequal teeth. Premandible (Fig. 38), with two light brown teeth and well-developed brush. SI (Fig. 39), plumose. Mandible (Fig. 40), with yellowish brown dorsal tooth; apical and two inner teeth blackish; inner margin with 2–3 spines. Mentum (Fig. 41), with slightly incised, trifid median tooth; and 6 pairs of blackish, lateral teeth; fourth lateral tooth smaller than fifth. Ventromental plates separated by about 1 / 5 width of mentum, anterior margin smooth. Abdomen. Anal tubules with median constriction; lateral tubules about 1 / 3 as long as 8 th abdominal segment; 2 pairs of ventral tubules, 1.8–2.5, 2.0 mm long. Remarks. The most similar Neotropical males are C. anonymus Williston, C. columbiensis Wülker, Sublette, Morath et Martin, and C. rincon Sublette et Sasa. C. antonioi can be separated from all these species on the coloration of the legs and the abdominal tergites. Further, the strongly inflated and abruptly tapered gonostylus, and the shorter wing length will also separate C. antonioi. The pupa is indistinguishable from most described pupae of Neotropical Chironomus species, except C. stigmaterus which has strong shagreenation on tergites IV–VI. The larvae of C. anonymus, C. columbiensis, C. reissi Correia, Trivinho-Strixino et Michailova, and C. strenzkei are the most similar Neotropical species. However, C. antonioi has a mentum with slightly incised trifid median tooth and the fourth lateral tooth is smaller than the fifth lateral tooth; in C. anonymus, C. columbiensis, C. reissi and C. strenzkei the median tooth is more deeply trifurcate, and the shape of the fourth and fifth lateral teeth also differ from C. reissi and C. strenzkei. Chironomus antonioi is also similar to the Neartic C. (Lobochironomus) austini (Beck et Beck), but the adults can be distinguished on the leg coloration and the wing length. The larva can be distinguished on the shape of pecten epipharyngis, as C. austini has several thinner teeth interspersed among normal teeth (see Epler 2001); and the reduced fourth lateral tooth of mentum, which is not reduced in C. austini. Ecology. Larvae of Chironomus antonioi were collected from roots of macrophytes in a section of the Boa Sorte Stream, located outside Jataí Ecological Station. At the sampling site the bottom substratum is sandy and covered with large stands of aquatic macrophytes, which reduces water flow. Detritus retained in the roots of the macrophytes led to a predominance of detritivores and collectors like Chironomus (Fonseca-Gessner & Guereschi 2000).Published as part of Correia, Leny Célia Da Silva & Trivinho-Strixino, Susana, 2007, New species of Chironomus Meigen (Diptera: Chironomidae: Chironominae) from Brazil, pp. 53-68 in Zootaxa 1504 on pages 57-61, DOI: 10.5281/zenodo.17715

New species of Chironomus Meigen (Diptera: Chironomidae: Chironominae) from Brazil

Correia, Leny Célia Da Silva, Trivinho-Strixino, Susana (2007): New species of Chironomus Meigen (Diptera: Chironomidae: Chironominae) from Brazil. Zootaxa 1504: 53-68, DOI: 10.5281/zenodo.17715