Parakari churiensis, Nieto, Carolina & Derka, Tomáš, 2011

Nieto, Carolina & Derka, Tomáš, 2011, Parakari a New Genus of the Family Baetidae (Insecta: Ephemeroptera) from Guyana Highlands, Zootaxa 3032, pp. 47-59 : 52-58

Parakari churiensis new species Nieto & Derka

( Figs. 2–3 , 15–30 )

Male imago ( Figs. 15–16 ). Length: body: 6.4–6.5 mm; fore wings: 6.9–7.0 mm. Head yellowish brown, antennae yellowish brown. Eyes ( Fig. 16 ): dorsal portion of turbinate eyes orange brown, stalk brownish, ventral portion black, bases of ocelli black. Thorax brownish ( Fig. 15 ), mesoscutum (MS) pale brown, submesoscutum (SMS) brownish. Metascutellum brownish, medial projection pale brown. Pleurae yellowish brown. Prosternum pale yellow, meso and metasterna yellowish brown. Legs pale yellow. Wings hyaline ( Fig. 17 ), costal and subcostal spaces of fore wings translucent. Abdomen pale yellow except segments VII–VIII brownish. Genitalia ( Fig. 18 ) yellowish. Cerci broken-off and lost.

Female Imago. Length: body: 5.7–6.0 mm; fore wings: 6.7–6.8 mm. Head reddish brown, antennae reddish brown; compound eyes blackish. Thorax: pronotum reddish brown, mesoscutum yellowish, submesoscutum brownish, metascutellum yellowish brown. Pleurae and sterna yellowish. Legs yellowish. Wings hyaline, costal and subcostal space of fore wings translucent. Abdomen: segments I–VIII reddish brown, segments IX–X pale yellow, sterna pale yellow. Cerci broken off and lost.

Nymph ( Figs. 2–3 ). Length: body: 5.2–5.5 mm; cerci: 2.5–2.6 mm; terminal filament: 2.3–2.4 mm. Head yellowish brown. Eyes: compound eyes orange brown, ocelli black. Antennae yellowish brown.

Mouthparts ( Figs. 19–24 ): Labrum ( Fig. 19 a) subquadrangulate, dorsally with two subapical setae near midline, one short and one long. Left mandible ( Fig. 20 ) with incisor positioned at obtuse angle to mola area, thumb of mola area transverse to anterior margin. Right mandible ( Figs. 21 a–b) with incisors elongated, prostheca bifid basally. Hypopharynx ( Fig. 22 ) with lingua subequal in length to superlinguae. Maxillae ( Fig. 23 a) with crown with two long pectinated setae, palpi longer than galea-lacinia, segment I longer than segment II. Labium ( Fig. 24 a) with paraglossae with two nonpectinated blade-like setae ( Fig. 24 b), segment II of palpi with a broad distomedial projection, segment III slightly longer than wide.

Thorax yellowish brown, fore wing pads yellowish. Metanotum brownish. Legs ( Fig. 25 ): femora yellowish, tibiae, tarsi and claws yellowish brown. Tarsal claws ( Fig. 26 ) with 10–11 denticles. Pleurae yellowish brown, sterna pale yellow.

Abdomen segments I–VI, IX–X ( Fig. 2 ) yellowish, segments VII–VIII brownish. Posterior margin of terga with rounded spines ( Fig. 27 ). Sterna pale yellow. Gills whitish ( Fig. 28 ), rounded, subequal in length of each tergum, main trachea pigmented. Paraprocts as in Fig. 29 . Caudal filaments yellowish ( Fig. 30 ).

Variation. some nymphs present the abdominal segments I–X yellowish ( Fig. 3 ).

Etymology. Churí-tepui is the name of the tepui from the Chimantá Massif where this species was collected.

Diagnosis. Parakari churiensis n. sp. can be distinguished from the other species of the genus by the following combination of characters. In the nymph: 1) labrum ( Fig. 19 a) dorsally with two subapical setae near midline, one short and one long; 2) left mandible ( Fig. 20 ) with incisors positioned at obtuse angle to mola area; 3) right mandible with incisors elongated ( Fig. 21 a), prostheca bifid basally ( Fig. 21 b); 4) hypopharynx ( Fig. 22 ) with lingua subequal in length to superlinguae; 5) maxillary palpi ( Fig. 23 a) longer than galea-lacinia; 6) labial palpi ( Fig. 24 a) with segment II with a broad distomedial projection; 7) posterior margin of abdominal terga with rounded spines ( Fig. 27 ). In the adult, 1) thorax with medioscutum pale brown, submedioscutum brownish.

Material. Holotype: male nymph: VENEZUELA, Bolívar Province, Chimantá Massif, Churí-tepui, Cueva Charles Brewer (the end), 17/ I/ 2009. T. Derka col. Paratypes: 34 nymphs the same locality and collector. 15 nymphs: spring stream below waterfall at Río Olinka originating in Cueva Juliana, 2300 m.a.s.l., Loc.8, 20/ I/ 2009, T. Derka col. 91 nymphs, 3 male and 12 female imagos (dried and damaged from spider web) and 2 male and 3 female subimagos: Quebrada Lila, a stream at the Plateau above Cueva Charles Brewer, 2400 m.a.s.l., Loc. 6, 26/ I/ 2009, T. Derka col. 132 nymphs, 10 female and 8 male subimagos (reared), 1 male imago (reared): Cueva Charles Brewer (entrance), 2300 m.a.s.l., 15/ I/ 2009, T. Derka col. 62 nymphs and 2 male imagos (reared): Quebrada Lila, a stream at the Plateau above Cueva Charles Brewer, 2400 m.a.s.l., Loc. 6, 21/ I/ 2009, T. Derka col. 52 nymphs: stream above Pozo Capuchino, 2300 m.a.s.l., Loc. 7, 16/ I/ 2009, T. Derka. 1 nymph: Río Olinka, stream above waterfall above Cueva Juliana, 2300 m.a.s.l., Loc. 11, 19/ I/ 2009, T. Derka col. 3 female imagos (dried and damaged from spider web), 7 male and 7 female subimagos: Canyon below Cueva Charles Brewer, 28/ I/ 2009, T. Derka col. 1 nymph: springs of Western river, Loc. 13, 23/ I/ 2009, T. Derka col. 55 nymphs: river below Cueva Juliana, ca. 2300 m.a.s.l., Loc. 9, 20/ I/ 2009, T. Derka col. 1 nymph: Cueva Colibrí, 26/ I/ 2009. Holotype and 63 paratypes are housed at IML; 20 paratypes housed at MIZA; other paratypes are housed at FNS.

Biology. All material was collected in streams at tepuis plateaus ( Figs. 31, 33 –35). The only exception was material from the stream below Salto Angel ( Fig. 32 ), the highest waterfall on the Earth (979 m), which drops down directly from the plateau of Auyán tepui. The material was collected from different types of streams, from spring streams to bigger mountain rivers. All streams are typically oligotrophic, with low conductivity from 9 to 18 μS.cm-2 and acid water with pH ranging between 3.75 and 4.58 (Table 1). Streams have mostly bedrock bottom with only minor accumulations of sands, gravels, stones and detritus. Due to geological conditions, nymphs must be able to withstand high current velocities and fluctuations without possibility to hide into hyporheal. Nymphs inhabit environments with wide range of temperatures from oligostenothermal cave streams with stable temperatures around 13–14 ºC to wide and shallow streams with high daily thermal fluctuations with maximum temperatures exceeding more then 21 ºC during sunny days. Subimagos were observed flying one hour before sunset. Potential predators of nymphs are dragonfly and dobsonfly larvae. Curiously, some nymphs of P. churiensis were found in bladder tramps of Utricularia humboldtii (T.D. pers. observ.).

Figures

FIGURES 1 – 3. Nymphs, dorsal habitus. 1, Parakari auyanensis sp. nov. 2, Parakari churiensis sp. nov. 3, Parakari churiensis sp. nov.

FIGURES 15 – 18. Parakari churiensis sp. nov. Male imago. 15, dorsal view (MS: mesoscutum, SMS: submesoscutum). 16, lateral view. 17, fore wing. 18, genitalia, C: constriction.

FIGURES 19 – 23. Parakari churiensis sp. nov. Nymph. Mouthparts (Figs. 19 – 23): 19 a, labrum, left d. v., right v. v.; 19 b, labrum: apical setae; 20, left mandible v. v.; 21 a, right mandible v. v.; 21 b, right mandible: prostheca detail; 22, hypopharynx v. v.; 23 a, maxilla v. v.; 23 b, denticles detail; 23 c, denticle I detail; 23 d, maxillary palpi, segment II detail.

FIGURES 24 – 30. Parakari churiensis sp. nov. Nymph. 24 a, labium, left d. v., right v. v.; 24 b, paraglossae: two nonpectinate blade-like setae detail. 25, leg I; 26, tarsal claw I. 27, posterior margin of tergum IV. 28, gill IV. 29, paraproct. 30, cercus.

FIGURES 31 – 33. Sampling sites. 31, Auyán Tepui, Río Churún (Loc. 9); 32, stream below Salto Angel; 33, Churí Tepui, stream at the Plateau above Cueva Charles Brewer (Loc. 6); 34, Churí Tepui, spring stream below waterfall at Río Olinka (Loc. 8); 35, Churí Tepui, Río Olinka (Loc. 11).