TRABAJO CIENTÍFICO

New record of Parochlus carolinae (Chironomidae: Podonominae) from the Ventania hill system with the description of the female

Nuevo registro de Parochlus carolinae (Chironomidae: Podonominae) del sistema de Ventania y descripción de la hembra

 

Siri, Augusto, Mariano Donato & Cecilia Fuentes

ILPLA (Instituto de Limnología "Dr. Raúl A. Ringuelet") CONICET-CCT-La Plata / UNLP. Bv. 120 y 62, La Plata (1900), Buenos Aires, Argentina. E-mail: augusto@ilpla.edu.ar

Recibido: 12-VI-2014;
Aceptado: 03-X-2014

 

---

ABSTRACT. The first report of Parochlus Enderlein from Ventania hill system is presented, being the first record of the genus from Buenos Aires province. The description and illustration of the female adult of Parochlus carolinae Rodriguez et al. is presented and the original male and larval descriptions are emended. Characters from the pupal thoracic horn are emphasized to distinguish P. carolinae from other Parochlus species.

KEY WORDS: Argentina; Neotropical region; Parochlus; E. Tornquist Provincial park; Sierra de la Ventana.

RESUMEN. Se presenta el primer reporte de Parochlus Enderlein del sistema serrano de Ventania, el cual constituye el primer registro de este género de la provincia de Buenos Aires. Se describe e ilustra la hembra de Parochlus carolinae Rodriguez et al. y se enmiendan las descripciones originales del macho y de la larva. Se remarcan caracteres del cuerno torácico de la pupa para distinguir P. carolinae de otras especies del género Parochlus.

PALABRAS CLAVE: Argentina; Parochlus; Parque provincial E. Tornquist; Región Neotropical; Sierra de la Ventana.

---

 

The Podonominae is a subfamily of Chironomidae whose immature stages inhabit cold streams and brooks. This subfamily was established for a few northern hemisphere species (Thienemann, 1937) while its presence and high diversity in the southern continents was posteriorly discovered and reported by Brundin (1966).

The Podonominae genus Parochlus Enderlein comprises 50 described species (Ashe & O'Connor, 2009, 2012) of which 29 were reported for the Neotropical region. In this region, Parochlus was widely reported in the Andean South America (from Peru to Tierra del Fuego and Navarino Islands), the Archipelago of South Chile, Juan Fernandez Islands, and an undescribed species from the higher elevations of Costa Rica. Parochlus carolinae was previously collected from the Carolina mountain stream and Grande River in San Luis Province, Argentina (Rodriguez et al., 2009), representing the single record of a named Parochlus species for the Neotropics outside the Andean Patagonia.

Brundin (1966) distinguished seven groups of species in the genus Parochlus, each of them differentiated in subgroups. In a recent molecular study (Cranston et al., 2010), four Brundin's species groups were represented but not all of them were resolved as such. In this study, the squamipalpis group and the genus Zelandochlus were considered into the araucanus group. Brundin (1966) reported considerable complications in the araucanus group, which was later confirmed by means of the molecular studies of Cranston et al. (2010).

Recently, we collected P. carolinae from the Ventania hill system. The Ventania system is part of the peripampasic orogenic arc defined by Frenguelli (1950) together with the Tandilia system, Mahuidas system, Pampean ranges and the Precordillera of northwestern Argentina. Ventania belongs to the biogeographic area of Distrito Pampeano Austral (Cabrera & Willink, 1980) extending along 170 km between 37°-39º S and 61°-63° W, in a NW-SE direction with the highest altitude of 1243 m a.s.l. (Kristensen & Frangi, 1995). Because of its orogenic condition, Ventania was considered "an island of biodiversity", in which the confluence of wildlife from the Brazilian region from the north and the Patagonia from the south occur (Ringuelet, 1961). To date, six chironomid species were reported from Ventania. Of these, Thienemaniella liae Paggi, Onconeura analiae Donato et al., Allocladius globosus Andersen et al. and Pseudosmittia sætheri Mauad et al. belong to the subfamily Orthocladiinae while Podonomus tehuelche Siri et Donato and P. quinquesetosus Siri et Donato belong to Podonominae. In the present study we extend the distribution records of P. carolinae to the Ventania hill system, being the first report for Buenos Aires Province and the easternmost report of the genus Parochlus for the Neotropics. In addition, we describe and illustrate the female of P. carolinae, and emend the male adult and the larva.

MATERIALS AND METHODS

Immatures were transported live in separate vials and reared in the laboratory following methods by Epler (2001). Specimens cleared were slide-mounted in Canada balsam. General terminology follows Sæther (1980). Measurements are in μm (excepting body and wing length, in mm).

Type material examined. ARGENTINA, San luis: Carolina stream, 32°50'S/66°2'W, 17-xi-2006, 1 male adult (HOLOTYPE), sweep net, Donato M. col. (MLP 5278/1); 1 larval cephalic capsule and pupal exuviae associated, 1 pupal exuviae, drift net, Donato M. col. (MLP 5278/3). Additional material studied. aRGENTINa, buenos aires: Parque Provincial "E. Tornquist", Cueva del Toro stream, 38º01'19.0''S/ 62º01'33.3''W, 672 m a.s.l., 4-xi-2011, malaise trap, Donato M., Siri A. & Spaccesi F. cols, 1 female; 21-v-2012, sweep net, 1 male and 1 female adults; unnamed stream at the piedmont of Bahia Blanca hill, 38º03'31.5''S/62º01'11.7''W 554 m a.s.l., 3-x-2013, hand net, exuviae; Donato M., Siri A. & Spaccesi F. cols, 1 male and female adults associated with their respective pupal exuviae, 1 male pupal exuviae.

RESULTS

Description

Female adult (n = 3, except when otherwise stated between parentheses) (Figs 1-5) Total length 1.77-2.16; total length/wing length 1.31-1.42; wing length/profemur length 3.25-3.44. Head. Eyes bare. Antenna with 11 flagellomeres (Fig. 1), AR 0.22-0.24. Ultimate flagellomere 55-70 long. Temporal setae 13-16 on each side, postorbital setae 6-8 on each side; 10-15 frontal setae. Clypeus with 6-10 setae. Lengths of palpomeres (1-5) 30-45; 55-75; 78-95; 72- 100 (2); 108-130 (2). Palpomere 2 globose. Thorax (Fig. 2). Antepronotum with 4-5 lateral setae; acrostichals 44-62; dorsocentrals 82-87 (2); prealars 40 (2); supraalars 2-4; scutellars 13-24; prescutellars 6-8; posnotals 0-2; preepisternals 6-7. Wing (Fig. 3). Length 1.30-1.64 mm; width 0.51- 0.66 mm; L/W 2.48-2.69. Costa extended 130-150 beyond R₄₊₅. Cell r₁ at distal end of vein R₁ 25-30; cell r₄₊₅ 160-200; r₁ width/r₄₊₅ width 0.15-016. All veins setose. Wing cells setose, except r₄₊₅. Brachiolum with 5 setae, squama with 5-7 setae. Legs. Tibial spur on p₁ 38-42 long; on p₂ 35-40 and 28-35 long; on p₃ 50-55 and 30-38 long. Comb on p₃ with 10 spines. Lengths and proportions of legs in Table I. Genitalia (Figs. 4-5). Cercus ovoid, 58-60 long. Seminal capsule 36-40 long; notum 160-170 long; sternite X with at least 10 short lateral setae.

Figs. 1-3 . Parochlus carolinae, female adult. 1, antenna; 2, thorax; 3, wing.

Figs. 4-5 . Parochlus carolinae, female adult. 4, genitalia, lateral view: drawing and photo; 5, genitalia, ventral view: drawing and photo.

Table I. Lengths (μm) and proportions of female legs of Parochlus carolinae Rodriguez et al. (n = 3). Abbreviations: femur (fe); tibia (ti); tarsomeres 1-5 (ta1-5); leg ratio (LR), ratio of metatarsus to tibia; "Beinver-hältnisse" (BV), combined length of femur, tibia, and basitarsus divided by combined length of tarsomeres 2-5; "Schenkel-Scheine-Verhältnis" (SV), ratio of femur plus tibia to metatarsus.

Emendation of male adult and larvae

MALE ADULT
The original description of the male of P. carolinae (Rodriguez et al., 2009) should be emended as follow:

Eyes bare; mandible absents, preepisternum with setae.

LARVAE
The original description of the larvae of P. carolinae (Rodriguez et al., 2009) should be emended as follow:

Labrum: SI 20 long, SII 24 long, with pedestal 16 long; SIII 16 long; SIVa 4 long, with pedestal 15 long; SIVb blunt rod 12 long. The shape of the pecten epipharyngis could not be observed.

Bionomy and comments

Immatures of P. carolinae were collected at Cueva del Toro streams and at an unnamed stream at the piedemont of Bahía Blanca hill, both located at the Parque Provincial Ernesto Torquinst, Buenos Aires, Argentina. Immatures were collected in temporal running streams. Water analysis of the Cueva del Toro stream showed the following values: PO₄-P 0.011- 0.670 (mg P/l); NO₂-N 0.001-0.034 (mg N/l); NO₃-N 0.088-0.296 (mg N/l); DBO <1-5 (mg O/l); DQO 5-22 (mg O/l); conductivity 81-114 (uS/cm); dissolved oxygen 9.00-13.98 (mg O/l) or 61-89 (%); temperature 9-11 °C.

Following Brundin's Parochlus species group, P. carolinae belongs to the araucanus group by the adult, pupal and larval characters. Due to the unresolved status of the subgroups of the araucanus group (see Cranston et al., 2010), we do not consider appropriate to force the inclusion of P. carolinae into one of these subgroups.

The eyes of the male adults of P. carolinae were originally described as hairy by Rodriguez et al. (2009), so these authors compared this species with P. duseni, since this is the other Parochlus species with hairy eyes. However, according to the analysis performed on the type material, P. carolinae eyes are bare. Other characters emended from the original description are the absence of mandible, and the presence of preepisternal setae of the male adults.

The best characters to distinguish the species of the araucanus group are present in the pupa (Brundin, 1966). Parochlus carolinae pupa has a strongly indicated horn sac of the thoracic horn, reaching 0.27-0.36 the length of the plastron plate. The horn sac in this species is practically indistinguishable from the felt chamber (see Fig. 11 in Rodriguez et al., 2009), which results in a diagnostic feature to distinguish the pupa of P. carolinae from the remaining pupae of Parochlus. The distal end of the felt chamber is represented by the aeropyles, which as in most of the Parochlus species connect at the proximal margin of the plastron plate. A more or less strongly indicated horn sac was also reported for P. patagonicus Brundin, P. ohakunensis (Freeman) and P. carinatus Brundin.

However, the shape of the thoracic horn of these species clearly differs from that of P. carolinae.

The finding of P. carolinae in the orogenic system has an important biogeographical significance, and it may be also distributed along the entire peripampasic orogenic arc. Further studies along the peripampasic orogenic arc are essential to understand the actual distribution and phylogeny of the subfamily Podonominae. Besides, the record of the genus Parochlus together with the occurrence of the genus Podonomus and Allocladius globosus reinforce the idea of Ringuelet (1961) in considering Ventania system as a complex area where Neotropical and Patagonian fauna occur.

A detailed revision of the different species of Parochlus is needed to elucidate the validation of the group species, as well as the biogeographical inferences and species relationships.

AKNOWLEDGEMENTS

Analía Paggi for providing type material of P . carolinae; Jorge Donadelli (ILPLA) for the water physico-chemical analysis, Anibal Areco and all of the park rangers of Parque Provincial E. Tornquist for helping us in the field work, OPDS for logistic support and for granting authorization to collect, Mónica Caviglia for English proof reading, and Fernando Spaccesi for his invaluable help in the field collection. The paper is the Scientific Contribution Nº948 of the Institute of Limnology "Dr. R.A. Ringuelet" (ILPLA, CCT-La Plata, CONICET, UNLP). This study is supported by CONICET and Agencia Nacional de Promoción Científica (PICT-2008-1910).

LITERATURE CITED

1. ASHE, P. & J. P. O'CONNOR. 2009. A World Catalogue of Chironomidae (Diptera). Part 1. Buchonomyiinae, Chilenomyiinae, Podonominae, Aphroteniinae, Tanypodinae,Usambaromyiinae, Diamesinae, Prodiamesinae and Telmatogetoninae, Irish Biogeographical Society & National Museum of Ireland, Dublin, 445 pp.         [ Links ]

2. ASHE, P. & J. P. O'CONNOR. 2012. Additions and corrections to Part 1 of 'A World Catalogue of Chironomidae (Diptera)'. Fauna norvegica 31: 125-136.         [ Links ]

3. BRUNDIN, L. 1966. Transantarctic relationships and their significance, as evidenced by chironomid midges. With a monograph of the subfamilies Podonominae and Aphroteniinae and the Austral Heptagyiae. Kunglika Svenska Vetenskapakadamiens Handlingar 11(1): 1-474.         [ Links ]

4. CABRERA, A. & A. WILLINK. 1980. Biogeografía de América Latina. Organización de Estados Americanos. Serie de Biología. Monografía No. 13, Washington, D.C. U.S.A.         [ Links ]

5. CRANSTON, P. S., N. B. HARDY, G. E. MORSE, L. PUSLEDNIK & S. R. MCCLUEN. 2010. When morphology and molecules concur: the 'Gondwanan' midges. (Diptera: Chironomidae). Systematic Entomology 35: 636-648.         [ Links ]

6. EPLER, J. H. 2001. Identification Manual for the larval Chironomidae (Diptera) of North and South Carolina. A guide to the taxonomy of the midges of the southeastern United States, including Florida. Special Publication SJ2001-SP13, North Carolina.         [ Links ]

7. FRENGUELLI, J. 1950. Rasgos generales de la morfología y la geología de la provincia de Buenos Aires. La Plata, Argentina: Laboratorio de Ensayo de Materiales e Investigaciones Tecnológicas, Serie II 33: 1-33.         [ Links ]

8. KRISTENSEN, M. J. & J. L. FRANGI. 1995. La Sierra de la Ventana: Una Isla de Biodiversidad. Ciencia Hoy 5(30): 25-34.         [ Links ]

9. RINGUELET, R. A. 1961. Rasgos fundamentales de la zoo­geografía de la Argentina. Physis 22(63): 151-170.         [ Links ]

10. RODRIGUEZ, M., A. C. PAGGI & A. I. MEDINA. 2009. A new Neotropical species of the genus Parochlus Enderlein, 1912 (Chironomidae: Podonominae) and new distribution in Argentina. Zootaxa 2300: 39-46.         [ Links ]

11. SAETHER, O. A. 1980. Glossary of chironomid morphology terminology (Diptera: Chironomidae). Entomologica scandinavica, Supplement 14: 1-51.         [ Links ]

12. THIENEMANN, A. 1937. Podonominae, eine neue Unterfamilie der Chironomiden (Chironomiden aus Lappland I). Mit einem Beitrag: Edwards F. W.: On the European Podonominae (adult stage). Internationale Revue der Gesamten Hydrobiologie, Hydrographie 35: 65-112.         [ Links ]