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Memórias do Instituto Oswaldo Cruz
Fundação Oswaldo Cruz, Fiocruz
ISSN: 1678-8060 EISSN: 1678-8060
Vol. 97, Num. 1, 2002, pp. 81-87
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Mem Inst Oswaldo Cruz, Rio de
Janeiro, Vol. 97(1) 2002, pp. 81-87
Araucnephia iberaensis
n. sp., a Neotropical Black Fly with a Peculiar Distribution (Diptera-Simuliidae)
S Coscarón/+, CL Coscarón-Arias*
Facultad de Ciencias Naturales y Museo, 1900
La Plata, Argentina *Facultad de Ciencias Agrarias, Cinco Saltos, Rio Negro,
Argentina
+Correponding author. Fax: +54-221-425.7527. E-mail: sixtoco@museo.fcnym.unlp.edu.ar
Received 21 March 2001
Accepted 24 July 2001
Code Number: oc02014
Araucnephia
Wygodzinsky & Coscarón is a Neotropical black fly genus in which
only one species from Central Chile is known. Another species has now been found
in Corrientes province on the eastern side of the Iberá tropical swamps
of Argentina, on the western border of the mountainous region of southern Brazil.
This new species, A. iberaensis, is herein described and illustrated and information
on its bionomics is recorded. It is an interesting species because previous
to its discovery no black fly genus or subgenus from Central Chile region has
been found in tropical areas, because these two regions are separated by the
Monte and Pampas realms. Similarly, no Brazilian genus or subgenus has crossed
the Andes mountains to Chile.
A comparison with other Neotropical, Nearctic,
Ethiopian (Afrotropical) and Australian Prosimuliini (sensu Crosskey & Howard)
showed Araucnephia
to be a valid taxon most closely related to Araucnephioides
(sympatric in Chile). Araucnephia
also shows great affinities with Lutzsimulium
from Southeast Brazil and Argentina and Paracnephia
from South Africa.
Key words: Neotropical black fly - new species
- Prosimuliini - Argentina
The Neotropical black fly fauna is composed of
330 species within 11 genera (Crosskey & Howard 1997). Nine of these genera
are within the tribe Prosimuliini (sensu Crosskey) and are exclusively
Neotropical. Seven are inhabitants of southern South America and are characterized
by their high degree of endemism (Coscarón & Coscarón-Arias
1995), as also are Simulium (Pter-naspatha) and Simulium "blancasi
group", both in the tribe Simuliini. Of the one genus of Prosimuliini and
11 subgenera of Simulium that occur on the oriental side of the Andes
in tropical South America, none is found on the other side of the Andes; similarly,
the black fly fauna from Chile and Argentina andean region are not found in
the lowlands at the East of Argentina as if through biogeographic history, a
strong barrier separates both regions. Until now the genus Araucnephia
Wygodzinsky & Coscarón 1973 was only represented by Araucnephia
montana (Philippi), that occurs in Chile from Coquimbo to Curicó.
This discovery of a second species for this genus from Northeast Argentina on
the mountainous western border with Southeast Brazil is of interest, because
until now no Chilean Simuliidae genera extend to the west of the Andean area.
The objective of this work is to describe a new
species of black fly and discuss its systematic position with regard to closely
related taxa.
MATERIALS
AND METHODS
The material was obtained by the first author
during three trips in June, August and November to the eastern border of Iberá
Reserve in Corrientes province, Argentina. The Iberá Reserve is an area
of wetlands known as the Esteros del Iberá and old Paraná river
bed now occupied by lagoons and large tropical swamps. Larvae and pupae were
collected in small creeks on the slopes of an undulating area near the provincial
road number 41, that runs along the border of the inundated area of the reserve.
In the same area man biting females and females entering the vehicle were also
collected between Ituzaingo and Galarza town. Immature stages and adults were
preserved in alcohol and some adults were pinned. Material was dissected after
treatment with sodium hydroxide solution and then mounted on slides in Canada
balsam. Drawings were made with a camera lucida.
Araucnephia iberaensis n.sp.
Female: wing length 2.7-2.8 mm. Color
generally blackish. Frons, clypeus, antenna, palpus and occiput black with grayish
pollinosity. Scutum and metanotum blackish, humeral and pre-scutellar areas
blackish brown with grayish pollinosity, scutellum blackish brown (Fig.
1A); wing veins light brown, legs brownish darkened on tarsites, halters
light brown; abdomen blackish with grayish pollinosity, tergal plates velvety
(brown in alcohol), darker than the rest of abdomen, pleura glabrous with grayish
pollinosity; thoracic pilosity grayish. Frons relatively wide with abundant
pilosity (Fig. 1B), frontal angle = 100°:
frontocular triangle a little wider than high (Fig.
1C). Clypeus about as long as wide. Antenna as Figure
1D. Palp with last article about twice length of penultimate, (Fig.
1E); sensory organ comparatively small, about 1/5 of basal article length,
with few tuberosities (Fig. 1F). Mandible
denticulate on both sides with 14 (15)-26(27) teeth (Fig.
1G); maxilla with 25 teeth (Fig. 1H).
Basal portion of cibarium smooth, with deep concavity rounded medially (Fig.
1I). Postoccipital cephalic area comparatively inflated (Fig.
1A). Thoracic hairs recumbent; wing with basal cell present; C with spinules
and setae; Sc with about 16-28 setae and 5-8 placoid setae. Basal sector of
R with hairs arranged in 2-3 rows and presence of placoid setae; R1 with finer
spinules than on C together with spines. Hairs on legs filiform with variable
size. Calcipala present and pedisulcus absent (Figs
1J-K); ratio length/width of basitarsus III = 8.5. Claws with small, sub-triangular-shaped
subbasal tooth (Figs 1L-M). Eighth sternum
mostly darkened with 21-24 trichomes, gonapophysis with 6-7 hairs, truncated
distally slightly sclerotized on internal side, and with rounded internal angle
(Fig. 1N). Cerci with rounded margin, paraproct
short (Fig. 1O); genital fork with thin
median branch and lateral branches expanded distally (Fig.
1P); spermatheca subovoidal with hyaline neck, showing some superficial
tubercles (Fig. 1Q).
Male: wing length 2.6-2.7 mm. General
coloration very similar to female, scutum brown, lighter on latero-posterior
border, metanotum velvety black, legs lighter brown with posterior half of femur,
tibia and tarsites blackish. Abdomen brownish, a longitudinal blackish stripe
composed of subtrapezoidal, sclerotized tergal plates on segments II-V and 1+1
sublateral spots on segments VI-VIII; ventrally with subquadrate spots blackish
on segments III-VIII (Fig. 2A). Antennal
shape as Fig. 2B. Sensory vesicle of palp
very small (Fig. 2C). Chaetotaxy of wing
as female. Ratio length/width of basitarsus III = 4.4. Furcasternum expanded
at sides of median branch (Fig. 2D). Dististyle
shorter than basistyle, subconical, with two longitudinal crest and distally
with a depression and two apical spurs (Figs
2E-I); ventral plate sub-pentagonal with small median crest (Fig.
2J); median sclerite robust in form of curved plate; endoparameres with
large basal plate and abundant and very small denticles distally; aedeagus membranous
with abundant microtrichiae (Figs 2K-L).
Pupa: cocoon length 3.6-4.2 mm; total
pupa length 6-6.3 mm, gill length 2-3 mm. Cocoon not compact, generally covering
pupa up to base of gill, fine weave to extent that threads not evident thereby
making pupa visible (Fig. 3A). Head of
pupa and body light brown. Frontoclypeus and thorax with abundant platelets
mostly verrucose, frontoclypeus with 1+1 frontal and facial trichomes, 2+2 epicraneal,
lateral and genal trichomes, all hair-like some curved distally (Fig.
3B). Thorax with 6-8 stout and single trichomes on each side, four more
robust on disk curved apically (Fig. 3C).
Gill with 9 terminal branches and short basal trunk, showing 3 short primary
branches carrying 2 secondary branches each, one of which is thinner and undivided
and other thicker and bifurcated at short distance from base (Fig.
3D); surface of filaments pitted. Abdomen hard, sclerotized with numerous,
small platelets, chaetotaxy as typical of genus, with strong terminal hooks
and several loopped trichomes (Figs 3E-F).
Larva: maximum length 6.6-7.6 mm. Color
light grayish brown. Head light brown with positive spots and very evident ornamentation,
with darker area around ocular spot (Figs 4A-B);
cephalic apotome spots blackish brown as follows: 1+1 basal submedian transverse
spots, one median longitudinal and 1+1 (2+2) small in the middle and inferior
third of head length (Fig. 4C). Cervical
sclerites wide, fused with upper ends of postocciput. Hypostomium with three
groups of teeth with median and corner teeth about same height and longer than
other teeth; laterally with 5-6 serrations on each side (Fig.
4D); lateral setae of hypostomium very long in number 4-5 on each side,
disposed in one or two rows, on disc 2-3 setae. Gular cleft shallow with soft
internal curve. Ratio hypostomium/hypostomial bridge = 0.6. Antennae about same
length as stem of cephalic fan. Basal articles robust (Fig.
4E); ratio of articles I-III = 1:1,2-1,5:2,4-2,8. Cephalic fan with 48-54
rays; comb of rays composed of series of smaller teeth between two long teeth
and half length of long teeth (Fig. 4F).
Mandible with two outer teeth, one apical and three pre-apical, with third hard
longer than others; internal teeth arranged in two rows with 11-13 teeth each;
8-12 marginal teeth, the first longest, two accessory teeth on the external
side sometimes present anterior to first or at same level as median internal
(Figs 4G-H). Palp elongated (Fig.
4I). Comb of pseudopod sclerite with 15-17 teeth and sclerite enlarged medially
(Fig. 4J). Anal sclerite X shaped (Fig.
4K) with single trichomes and abundant scales with 4-8 branches (Fig.
4L). Anal ring with 64-66 rows of 14-16 hooks each. Anal gill with 3 long
lobes undivided (Fig. 4M).
Material examined: ARGENTINA: Corrientes
on provincial route number 41, between Federal Highway 12 crossing State Way
41 (S 27°40'49", W 56°28'27") and Galarza town (S 28°06'03",
W 56°39'51"), col. S. Coscarón (MLP), 1/2-06-00, man biting:
2 females (paratypes) on pick-up: 1 female (Holotype); creek 5 km South to Estancia
San Antonio: 2 pupae, 4 larvae, (sympatric with Simulium perflavum Roubaud;
same locality, 6-XI-00: 1 larva, (sympatric with S. minuanum Strieder
and Coscarón and S. delponteianum Wygodzinsky) (S 27°48'44",
W 56°24'49"), 6-XI-00: 1 pupa 6 larvae; creek 5 km South of Itacua:
4 pupae, 12 larvae (sympatric with S. subpallidum Lutz); creek 8 km North
of Galarza: 2 pharate female and 1 pharate male on slides (paratypes), 8 pupae,
4 larvae (sympatric with S. minuanum); creek 2 km North of Galarza: 2
pupae, 2 larvae and 2 larvae in slides (sympatric with S. perflavum,
S. subpallidum, S. pertinax Kollar, S. minuanum and
S. (Inaequalium) sp. Same area 13-08-00. Second creek South of Highway
12 to Itacua: 1 pupa (sympatric with S. perflavum, S. minuanum
and S. inaequale (Paterson & Shannon); Fourth creek S. Highway 12:
1 female pinned (paratype) 2 pupae, 6 larvae (sympatric with S. inaequale
and S. minuanum); creek 3 km South Itacua: 8 larvae (sympatric with S.
minuanum and S. auripellitum Enderlein; creek between Itacua and
Galarza: 1 pharate female and 2 pharate male (paratypes), 2 larvae on slides,
13 pupae and 9 larvae. Creek in front of park guard's house: 1 pharate male
on slide (paratype), 3 larvae (sympatric with S. perflavum and S.
minuanum). All material is deposited in Museo La Plata, Argentina.
Bionomics: A. iberaensis breeds
in small creeks 0.5-3 m wide, and 0.1-0.5 m deep with crystalline water and
strong but not torrential current speed. Larvae and pupae found on aquatic vegetation.
Females are hematophagous and bite man. The bite produces a hard spot followed
by an allergic reaction. This reaction is one of the worst suffered by the collector
from a black fly bite.
Discussion: the new taxon is within the
genus Araucnephia as originally defined by Wygodzinsky and Coscarón
1973. Characters to separate A. iberaensis from A. montana are
as follows: A. montana has pupal gill with 14 branches, frontoclypeus
and thorax without platelets, trichomes of thorax straight distally; in larva
head dark brown and the dorsal dark spots not well defined; gular cleft deeper
with ratio hypostomium/hypostomial bridge = 1, median tooth of hypostomium at
same or beyond level of lateral teeth, antenna shorter than stem of cephalic
fan, marginal serrations of mandible with 7-15 denticles and absence of large,
anteriorly positioned accessory tooth, cephalic apotome sclerite with transverse
maximum width some distance above of base, cephalic fan with about 24 rays showing
comb teeth of rays of similar length and lateral sclerite of pseudopodium with
about 56 teeth. Minor differences occur in larval antennal article length, and
number of maxilla and mandible teeth.
A comparative morphological analysis of Araucnephia
(Wygodzinsky & Coscarón 1973) revealed that this genus is most closely
related to Araucnephioides and shows little affinity with other Neotropical
Prosimuliini and some Nearctic genera. One taxon superficially treated in that
revision was Paracnephia (Paracnephia) from the Ethiopian (Afrotropical)
region, that we compare in more detail here (Table).
Lutzsimulium is also included because it is now known to be sympatric
with genera of the tribe Prosimuliini. These analyses demonstrate several characters
in common, suggesting that these genera plus Araucnephioides probably
have a Gondwanian common ancestor.
ACKNOWLEDGEMENTS
To Dr Blanca Alvarez de Avanza (Faculty of Exact
and Natural Sciences of the North East University) for logistical support for
fieldwork through the Iberá Project. To Dr AJ Shelley from the British
Museum of Natural History for the suggestions to the text and the loan of Paracnephia
species from South Africa. To Nélida R Caligaris for the illustrations.
REFERENCES
- Coscarón S, Coscarón-Arias CL
1995. Distribution of Neotropical Simuliidae (Insecta-Diptera) and its areas
of endemism. Rev Acad Colomb Cienc 19: 717-732.
- Crosskey RW, Howard TM 1997. A New Taxonomic
and Geographical Inventory of World Blackflies (Diptera: Simuliidae), The
Natural History Museum, London, 144 pp.
- Wygodzinsky P, Coscarón S 1973. A review
of Mesoamerican and South American black flies of the tribe Prosimuliini (Simuliinae,
Simuliidae). Bull Amer Mus Nat Hist 151 (art. 2): 129-200.
© 2002
Instituto Oswaldo Cruz - Fiocruz
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