Pseudochironomus jordensis, Trivinho-Strixino, 2017

Trivinho-Strixino, Susana, 2017, Brazilian Pseudochironomini (Diptera: Chironomidae) Part 1. New Pseudochironomus Malloch from highlands, Zootaxa 4317 (1), pp. 134-154 : 143-148

Pseudochironomus jordensis sp. n. Shimabukuro & Trivinho-Strixino

Type material. Holotype male, BRAZIL, SP, CampoS do Jordão , Galharada Stream , 3rd order, 22°41”.29’S, 45°27”.42´W, 1584 m a.S.l., 14.ii.2002 (I1 – 25, LEIA-UFSCar). M. T. Suriano. Paratype: two male, Same data aS holotype (I1 – 26–27, LEIA-UFSCar), one male, Same data aS holotype, except for 05.xi.2001 (I1 – 28, LEIA- UFSCar), one pupal exuVia with larVa’S cephalic capSule, Same date aS holotype, except for 13.ix.2001 (I1 – 29, LEIA-UFSCar), one male pharate pupa with larVa’S cephalic capSule, male not completely mature, Same date aS holotype, except for 12.xi.1999 (I1 – 30, LEIA-UFSCar), and one pupa exuVie from BRAZIL, SP, CampoS do Jordão, Campo do Meio Stream, 2nd order, 22°41”.35’S, 45°29”23´W, 1500 m a.S.l., 13.ix.2001 (I1 – 31, LEIA- UFSCar), M. T. Suriano. FiVe larVae, Same data aS holotype, except for 9.xi.2001 (I1 – 32, LEIA-UFSCar).

Etymology. The Specific name iS in reference to the CampoS do Jordão State Park, where the SpecieS waS found.

Diagnostic characters. Adult male: total length 3.63–4.15 mm; wing length 2.6 8– 2.83 mm; preSence of thoracic acroSticalS; TIX broad, with a median terminal notch that do not reach the inferior VolSella; gonoStyluS broad and Short; median VolSella fine, carrying only two Strong and long Seta; Superior VolSella bare, with only one long Seta; parS VentraliS completely diVided. Pupa: exuVia light brown; preSence of a pair of tubercleS on SI, with many Small SpineS; TI with two patcheS of Shagreen; median and poSterior precornealS ariSing from an apparently tough protuberance; TVI, TVII and TVIII with broadened D1 Setae; anal lobe with 22–30 taeniate Setae. Larva: mentum; clawS of parapodS and mandible teeth, except apical tooth, dark brown; and cephalic capSule brown; mentum with 11 teeth; fifth and Sixth lateral teeth not fuSed; Sixth lateral tooth narrow, almoSt the half of fifth tooth’S width; baSal Segment of antenna Slightly Smaller than premandibule; AR = 1.33–1.67.

Male (n = 4)

Total length 3.63–4.15 mm. Wing 2.68–2.83 mm long, and 0.88–0.89 mm wide. Total length/wing length 1.28–1.51. Wing length/length of profemur 2.23–2.63.

Colouration: Thorax with brown markS ( Fig. 1 b). TergiteS with brown bandS and pale SpotS in the inSertion of Setae. Femur yellow, tarSi with intenSe dark brown colour.

Head. AR = 3.32 (1). Antenna 1040 (1) µm long. 13 flagellomereS. LaSt flagellomere 800–831 µm long. ClypeuS with 24–29 Setae. Palpomere 1–5 lengthS 63–75; 63–125; 188–200, 244–281; 313–375 µm. Third palpomere with a Slight fingerlike proceSS.

Thorax ( Fig. 1 b). AcroStichalS 5, uniSerial (3) ( Fig. 1 b); AntepronotalS, in lateral poSition 4–8 (3), Small; dorSocentralS 13–17 (3) in a Single row, ariSing from pale areaS; prealarS 5–6 (3); Scutellum with 19–33 (3) Setae, double row.

Wing. VR 1.11–1.16. Brachiolum with 2 Setae, R with 21–28 Setae, R1 with 9–12, R4+5 5–8 apical Setae. Squama with 25–30 Setae.

Legs. Spur of fore tibia 63–75 µm long; SpurS of mid tibia 66–94 µm and 81–93 µm long; SpurS of hind tibia 59–91 µm and 81–100 µm long. Length and legS proportionS aS in Table 4.

Hypopygium ( Fig. 6 a). Tergite IX broad, poSterior margin with a median notch that do not reach the inferior VolSella ( Fig. 6 c) with 8–15 Setae. LateroSternite IX with 8–11 (3) Setae. Phallapodeme 108–115 µm long. TranSVerSe Sternapodeme 137–155 µm long. Superior VolSella bare ( Fig. 6 b) 108–126 µm long curVed, apically concaVe ending aS two pointS, with one point 26 µm and the other 9 µm long, and with only one long Setae 31 µm; inferior VolSella foot Shaped, 95–106 µm long, longeSt apical Setae on inferior VolSella with 32–46 µm long, median VolSella fine and long 18–22 µm, bearing 2 apical Setae long 38–49 µm and Strong. Gonocoxite 198–254 µm long. GonoStyluS broad and Short 157–197 µm. HR = 1.2–1.3. ParS VentraliS ( Fig. 6 d) completely diVided into two 68–77 (2) µm long and 11–12 (2) µm wide lobeS.

Pupa (n = 3)

Total length 4.9–5.7 mm. ExuViae light brown.

Cephalotorax ( Fig. 7 f). Frontal Setae abSent. Thoracic horn, 169–312 µm long, Smooth. Three precornealS, median and poSterior ariSing from a tough protuberance; Anterior precorneal 100–114 (2) µm, median 157–180 µm, poSterior 55–138 µm long; 2 antepronotalS, one with 114–131 µm and the other with 197–209 µm, 4 dorSocentralS, Dc1 66–123 (2) µm long, Dc2 64–183 µm long, Dc3 56–128 (2) µm long, Dc4 77–85 µm long (2), diStance from Dc1 and Dc 2 29–65 µm; diStance from Dc3 and Dc4 77–85 µm; diStance from Dc2 and Dc3 428–497 µm.

Abdomen ( Fig. 7 a–b). Tergite I with two patcheS of Shagreen. TII–TVI coVered with Shagreen, and TVII–TVIII with Shagreen on anterior margin. TV–TVIII with broadened D1 Setae ( Fig. 7 e). TIII with anterior band of Strong Spinulae. Hook row continuouS with near 61–78 curVed SpineS occupying near 1/3 width of Segment II. ConjunctiVeS III/IV to IV/V with 6 rowS of Sclerotized SpinuleS. TIII–TVI SometimeS preSentig poSterior dark SpotS. SI with one pair of tubercleS with many Small SpineS ( Fig. 7 c); PedeS Spurii A abSent. Segment VIII with poSterolateral comb with 4–7 caudolateral SpineS ( Fig. 7 d), 25–28 µm long. Segment II and III with one Small L Setae and one dorSolateral Setae. Segment IV with one L Seta. PedeS Spurii B preSent on Segment II and III but Very Slight. Segment V–VIII with 3, 4, 4, 5 L taeniate Setae. Anal lobe 2 61–338 µm long, with 22–30 double fringe of taeniate Setae and a pair of dorSal Setae.

Larva (n = 4)

Colouration. Head brown; mentum, mandibular teeth except apical tooth, clawS of parapodS and occipital margin dark brown.

Head. 462–692 (2) µm wide. Antenna with 5 SegmentS, length of antennal SegmentS (µm) 107–112; 20–28; 12–21; 11–15; 5–8 µm ( Fig. 8 b). AR = 1.33–1.67. Antennal blade 66–85 µm long. Lauterborn organ 9–11 µm long. Premandible 118–131 µm long ( Fig. 8 f). Pecten epipharyngiS 8–18 µm long ( Fig. 8 d). Mentum 154–200 µm long ( Fig. 8 a), with median tooth and 5 lateral teeth, Second lateral tooth Small and fuSed with the firSt lateral tooth, fifth and Sixth teeth not fuSed; Sixth tooth narrow, approximately with half of fifth tooth’S width. Mentum/head ratio: 0.27–0.34. DiStance between Submental Setae: 151–200 µm. Ventromental plateS 35–40 µm wide. Mandible 168– 226 µm long ( Fig. 8 e). DorSal ScleriteS of head aS in figure 8c.

Abdomen. 9–10 mm long. ProcercuS with 8 Setae. Anal Setae 394–625 (2) µm long. SubbaSal Setae on procercuS 74–88 (2) µm. Anal tubuleS, 192–254 (2) µm long. SubaSal Seta on parapod 34–80 (2) µm long. ParapodS clawS dark brown.

Remarks. The male of P. jordensis sp. n. differS from P. ruah sp. n. by itS Small body Size; Size and Shape of TIX, which iS Shorter in P. jordensis sp. n.; and by the format of the median VolSella, which iS narrow and longer in P. jordensis sp. n., and by the number and thickneSS of Setae on it, once P. jordensis sp n. preSentS only two Strong and long Setae, while P. ruah haS Variable number of thin Setae on median VolSella.

The pupa of P. jordensis sp. n. reSembleS the pupa of P. ruah sp. n. and alSo the P. richardsoni one. It differS from P. ruah sp. n. by the number of SpineS in the tubercleS of SI, which are more numerouS in P. jordensis sp. n.. AlSo, D1 Setae on TVI, TVII and TVIII are approximately two timeS wider in P. jordensis sp. n., and contrary to P. ruah sp. n., the SpecieS preSent two patcheS of Shagreen in TI. P. jordensis sp. n. and P. ruah sp. n. pupae alSo differS from P. richardsoni oneS in Size and Shape of thoracic horn.

The larVa of P. jordensis sp. n. iS Similar to the P. articaudus one, due to the format and the number of teeth in mentum, but they differ in AR ratio and in the Size of baSal Segment of antenna, which are higher in P. jordensis sp. n.. The larVa of P. jordensis sp. n. can be diStinguiShed from P. ruah sp. n. by the darker colour of teeth and clawS in P. ruah sp. n.. AlSo, the laSt Sixth tooth in mentum iS Smaller than the fifth and not fuSed in P. jordensis sp. n..

Ecological notes. LarVae were collected in mountain StreamS from SoutheaStern Brazil, with low depth and tranSparent water, diSSolVed oxygen 8.6–10.4 mg.l -1 and pH about 5–6. The altitude at the Sampling SiteS waS higher than 1500 m a.S.l.

Figures

FIGURE 1. Thorax and detail of the acrostichals and setal scars on scutum, lateral vieW. a. Pseudochironomus ruah sp. n.. b. Pseudochironomus jordensis sp. n.. c. Pseudochironomus mocidade sp. n.. d. Pseudochironomus surianae sp. n..

FIGURE 6. Pseudochironomus jordensis sp. n. adult male. a. hypopygium, left dorsal right ventral vieW. b. superior volsella. c. posterior margin of tergite IX. d. pars ventralis.

FIGURE 7. Pseudochironomus jordensis sp. n. pupa. a. abdomen, TI-TV. b. abdomen, TVI-TVIII and anal lobe. c. tubercle from SI. d. posterolateral comb on segment VIII e. from left to right: D 1 setae from TV-TVIII. f. thorax.

FIGURE 8. Pseudochironomus jordensis sp. n. larva. a. mentum and ventromental plate. b. antenna. c. dorsal sclerites of head d. pecten epipharyngis. e. mandible. f. premandible.