Neotropical Ichthyology, 6(2):175-180, 2008
Copyright © 2008 Sociedade Brasileira de Ictiologia
Austrolebias paucisquama (Cyprinodontiformes: Rivulidae),
a new species of annual killifish from southern Brazil
Juliano Ferrer1, Luiz R. Malabarba1 and Wilson J. E. M. Costa2
Austrolebias paucisquama is described from the rio Vacacaí drainage, a tributary to the rio Jacuí, Rio Grande do Sul, Brazil. The
new species belongs to the Austrolebias alexandri species-group, by sharing the apomorphic bright blue iridescence and
dark gray pectoral fins in males. It is distinguished from other species of this group by having fewer scales around caudal
peduncle (12) and fewer dorsal-fin rays in males (17-21). The lack of contact organs on the inner surface of the pectoral fin in
males and the color pattern of females – ground color light brownish, sides of body with a variable number of relatively large
dark black spots distributed mostly on posterior portion of body – distinguish A. paucisquama from all other species of the
genus.
Austrolebias paucisquama, uma nova espécie de peixe anual é descrita da bacia do rio Vacacaí, tributário do rio Jacuí, Rio
Grande do Sul, Brasil. A nova espécie pertence ao grupo Austrolebias alexandri, que apresenta duas apomorfias, pontos azuis
claros e nadadeiras peitorais cinza escuro nos machos. Distingue-se das outras espécies do grupo pelo reduzido número de
escamas ao redor do pedúnculo caudal (12) e pelo menor número de raios na nadadeira dorsal dos machos (17-21). A ausência
de órgãos de contato na superfície interior das nadadeiras peitorais nos machos e o padrão de colorido das fêmeas – flancos
marrom claro com variável número de pontos pretos relativamente alongados distribuídos principalmente na porção posterior
– distinguem A. paucisquama das outras espécies do gênero.
Key words: Systematics, Austrolebias alexandri species-group, Endangered species.
Introduction
Austrolebias Costa is a genus of annual killifishes whose
species inhabit seasonal and temporary pools and swamps
formed during the rainy season in southern Brazil, Paraguay,
Uruguay, and north and northeast Argentina (Costa, 2006).
The genus has been recently phylogenetically redefined by
Costa (2006), including the species previously referred to
Megalebias Costa. Monophyly of the genus was supported
by the following synapomorphies: (a) absence of scales between corner of mouth and anterior portion of preopercular
region and ventral portion of opercular region, (b) a deep
urohyal, and (c) a dark gray to black infraorbital bar and supraorbital spot. Additional synapomorphies proposed for
Austrolebias, but independently acquired by other
cynolebiatines were: (a) dorsal and anal fins rounded in males,
(b) a long urogenital papilla in males, and (c) a reduced ventral
process of the angulo-articular.
Costa (2002) recognized five species as belonging to A.
alexandri species-group: A. affinis (Amato), A. alexandri
(Castello & Lopez), A. cyaneus (Amato), A. ibicuiensis (Costa)
and A. periodicus (Costa). In a more recent review, Costa
(2006) redefined the group based on the apomorphic dark gray
pigmentation of the pectoral fins and the bright blue iridescence in males, and has expanded the group including A.
duraznensis (García, Scvortzoff & Hernandéz), A. juanlangi
Costa, Cheffe, Salvia & Litz, A. litzi Costa, A. nigripinnis
(Regan) and A. paranaensis Costa. The species A. luzardoi
described by Perujo et al. (2005) also belongs to this group.We
herein describe a new species of Austrolebias from the rio
Vacacaí drainage, a tributary of the rio Jacuí, Rio Grande do
Sul, Brazil. The new species also belongs to the Austrolebias
alexandri species-group.
1
Departamento de Zoologia, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS, Brazil.
julianoferrer@bol.com.br; malabarb@ufrgs.br
2
Laboratório de Ictiologia Geral e Aplicada, Departamento de Zoologia, Universidade Federal do Rio de Janeiro, P. O. Box 68049, 21944970 Rio de Janeiro, RJ, Brazil. wcosta@acd.ufrj.br
175
A new species of annual killifish from southern Brazil
176
Fig. 1. Austrolebias paucisquama, holotype, MCP 41879, male, 34.2 mm SL, Rio Grande do Sul, São Sepé, temporary pool
close to BR290 highway (30°22’27'’S 53°33’42'’W), rio Vacacaí drainage.
Material and Methods
Counts and measurements follow Costa (1995). All measurements are presented as percents of Standard Length (SL),
except subunits of head presented as percents of Head
Length. All radial elements are included in fin rays counts.
Osteological observations were made in specimens cleared
and stained (c&s) according to the method described in Taylor & Van Dyke (1985). Rostral squamation pattern is described
according to Hoedeman (1958) and cephalic neuromasts according to Costa (2001). Examined specimens belong to the
following institutions: MCP - Museu de Ciências e
Tecnologia, Pontifícia Universidade Católica do Rio Grande
do Sul; UFRGS - Departamento de Zoologia, Universidade
Federal do Rio Grande do Sul; UFRJ - Universidade Federal
do Rio de Janeiro.
mm SL; and UFRGS 9354, 3 males (3 c&s), 22.1-24.9 mm SL,
collected with the holotype. UFRGS 9355, 6 males, 21.0-28.5 mm
SL, 1 female, 21.4 mm SL, same locality of the holotype, 9 Jun
2005, J. Ferrer, J. Giora, R. Hirano & D. Rocha.
Diagnosis. The dark gray pectoral fins combined with the
bright blue iridescence in males distinguishes A. paucisquama
Results
Austrolebias paucisquama, new species
Figs. 1 - 3
Holotype. MCP 41879, male, 34.2 mm SL, Brazil, Rio Grande do
Sul, São Sepé, temporary pool close to BR-290 highway (30°22’27”S
53°33’42”W), rio Vacacaí drainage, rio Jacuí tributary, 15 Sep 2004,
J. Anza, J. Giora & A. Pereira.
Paratypes. Brazil: Rio Grande do Sul: UFRJ 6522, 5 males (1 c&s),
25.2-27.7 mm SL, 5 females (1 c&s), 25.6-34.0 mm SL; MCP 41880,
12 males (2 c&s), 22.4-31.7 mm SL, 14 females (1 c&s), 18.8-34.8
Fig. 2. Austrolebias paucisquama, paratype, MCP 41880, male
25.5 mm SL, Rio Grande do Sul, São Sepé, temporary pool
close to BR290 highway (30°22’27”S, 53°33’42”W), rio Vacacaí
drainage. Same specimen alive (above) and just after fixation
in formalin (below).
J. F. dos Santos, L. R. Malabarba & W. J. E. M. Costa
177
Fig. 3. Austrolebias paucisquama, paratype, MCP 41880, female 32.6 mm SL, Rio Grande do Sul, São Sepé, temporary pool
close to BR290 highway (30°22’27”S 53°33’42”W), rio Vacacaí drainage.
from other species of the genus Austrolebias, except from
those of the A. alexandri species-group. The fewer scales
around caudal peduncle (12 vs. 16 or more) and the fewer
dorsal-fin rays in males (17-21 vs. 20 or more in A. litzi and A.
nigripinnis; 21 or more in A. affinis, A. alexandri, A. cyaneus,
A. juanlangi and A. luzardoi; 22 or more in A. duraznensis, A.
ibicuiensis, A. paranaensis, A. periodicus) distinguish A.
paucisquama from other species of the A. alexandri speciesgroup. The lack of contact organs on the inner surface of the
pectoral fin in males and the color pattern of females – ground
color light brownish, sides of body with a variable number of
relatively large dark black spots distributed mostly on posterior portion of body – distinguish A. paucisquama from all
other species of the genus.
Description. Morphometric data on Table 1. Largest male 34.2
mm SL; largest female 34.8 mm SL. Body compressed. Dorsal
head profile slightly concave, more evident in females. Dorsal profile convex from nape to insertion of last dorsal-fin ray.
Ventral profile concave from lower jaw to last anal-fin ray
Table 1. Morphometric data of Austrolebias paucisquama. Ranges presented for males include the holotype. n = number of
specimens.
Standard length (mm)
Body depth
Caudal peduncle length
Predorsal length
Prepelvic length
Length of dorsal-fin base
Length of anal-fin base
Caudal-fin length
Pectoral-fin length
Pelvic-fin length
Head length
Head depth
Head width
Eye diameter
Snout length
Males
Holotype
n
Low High
MCP 41879
34.2
23 21.0 34.2
Percents of standard length
34.2
23 27.1 34.5
14.3
23 11.9 15.6
51.3
23 43.9 54.0
48.3
23 42.6 48.7
37.0
23 32.7 41.9
39.5
23 31.6 39.8
20.0
23 18.0 27.6
18.5
23 11.7 22.7
10.0
23
6.3
11.0
29.8
23 28.4 32.7
28.0
23 24.3 30.0
18.5
23 15.7 21.1
Percents of head length
25.5
23 24.8 33.0
31.3
23 21.1 34.0
Mean
n
Females
Low High
Mean
26.5
19
19.7
34.8
27.3
31.8
13.7
50.7
45.9
37.0
36.2
21.2
18.2
9.2
30.5
27.3
18.7
19
19
19
19
19
19
19
19
19
19
19
19
28.6
11.3
54.8
48.6
23.2
19.9
17.0
15.0
8.7
27.6
23.7
18.2
35.0
14.8
61.5
54.2
30.6
25.4
25.6
22.5
12.0
31.8
28.6
21.5
31.4
13.0
58.4
51.0
26.3
22.2
20.5
18.3
10.5
30.2
26.4
20.2
28.0
27.1
19
19
21.7
22.3
30.9
28.0
27.7
25.4
178
A new species of annual killifish from southern Brazil
insertion. Dorsal and ventral profiles of caudal peduncle nearly
straight. Maximum body width at least 2.21 in maximum body
depth. Greatest body depth at pelvic-fin insertion. Snout blunt.
Jaws short.
Dorsal and anal fins rounded. Anterior anal-fin rays in
females prolonged forming anterior lobe; in males all anal-fin
rays with approximately same length and not forming lobes.
Anal-fin origin just posterior or just anterior to dorsal-fin origin in males; posterior to dorsal-fin origin, at vertical through
base of second to fourth dorsal-fin rays in females. Base of
dorsal-fin origin at vertical between 8th and 9th pleural ribs in
males and between 11th and 12th pleural ribs in females. Base
of anal-fin origin at vertical between 8th and 9th pleural ribs
in males and between 12th and 13th pleural ribs in females.
Urogenital papilla not attached to anal fin. Caudal fin rounded.
Pectoral fins elliptical, posterior margin on vertical between
urogenital papilla and base of 2nd anal-fin ray in males, reaching or almost reaching pelvic-fin base in females. Tip of each
pelvic fin reaching base of 2nd or 3rd anal-fin rays in males,
between urogenital papilla and base of 1st anal-fin ray in
females. Pelvic-fin bases in close proximity, medial membrane
not united. Dorsal-fin rays 17-21 in males and 15-21 in females. Anal-fin rays 19-23 in males and 17-19 in females. Caudal-fin rays 23-27, usually 25. Pectoral-fin rays 11, rarely 12.
Pelvic-fin rays 4-5.
Scales large and cycloid. Trunk and head scaled, except
ventral surface of head. No scales on dorsal and anal-fin bases,
and two rows of scales on caudal-fin base. Frontal squamation H-patterned. Longitudinal series of scales 25-26, regularly arranged; transversal series of scales 11-13; scale rows
around caudal peduncle 12. Minute contact organ on each
scale of anteroventral portion of flank in males. No contact
organs on fins.
Cephalic neuromasts: supraorbital 15-21, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital 24-28, preorbital
2, otic 1-2, post-otic 1-3, supratemporal 1, median opercular 1,
ventral opercular 2, preopercular 19-22, mandibular 8-11, lateral mandibular 4-6. Six branchiostegal rays. Gill-rakers on
first branchial arch 2+8. Total vertebrae 28-30.
Life coloration in males. Ground color dark gray. Sides of
body with 6, 7 or rarely 8 iridescent greenish-blue vertical
bars, two or three times narrower than space between each
pair of bars, and not extended to dorsum. Urogenital papilla
gray. Opercular and infraorbital regions greenish-blue, with
vertical and near rectangular dark bar below eye and small
dark grayish triangular spot dorsoposterior to eye not reaching parietal neuromasts. Iris white anteriorly and posteriorly;
red and black pigmented vertical bar crossing center of eye.
Dorsal and anal fins iridescent greenish-blue, sometimes with
light spots; usually grayish near fins base. Caudal fin iridescent greenish-blue, except at distal portion. Pelvic and pectoral fins bright iridescent blue. Distal border of dorsal, anal,
pectoral and pelvic fins black pigmented (Fig. 1).
Color in males just after fixation in formalin. Color pattern
of bars and spots basically same in life and just fixed specimens. General body color, however, changes drastically. Red
pigments do not change, but iridescent greenish-blue pigments become very intense blue, giving general dark blue
appearance to fish (Fig. 2).
Life coloration in females. Ground color light brownish. Sides
of body with variable number of relatively large dark black
spots, distributed mostly on posterior portion of body. Purple
line discernible approximately on distal border of hypural fan.
Belly golden in all observed females. Urogenital papilla light.
Opercular region, and sometimes infraorbital region bright
green, with vertical and narrow dark bar below eye. Iris white
anteriorly and posteriorly, and black pigmented below and
above the pupil. All fins hyaline (Fig. 3).
Distribution. Known only from the type-locality, a temporary
pool in the rio Vacacaí drainage, rio Jacuí tributary, laguna
dos Patos drainage (Fig. 4).
Habitat. The type locality consists of a small temporary pool
located close to the BR290 highway, and distant from any
permanent freshwater flow in the altitude of 154 m (Fig. 5).
The specimens of Austrolebias paucisquama were the only
Fig. 4. Southern Brazil and Uruguay, showing the type locality (black circle) of Austrolebias paucisquama.
J. F. dos Santos, L. R. Malabarba & W. J. E. M. Costa
179
group, by sharing the apomorphic bright blue iridescence
and pectoral fins dark gray in males. However, A. paucisquama
is easily distinguished from all species of the genus by the
lack of contact organs in the pectoral fins of males, the reduced number of scales around caudal peduncle, the reduced
number of dorsal-fin rays in males and the color pattern of
females.
Most Austrolebias species inhabit lowlands and inundated areas adjacent to permanent waters, in altitudes usually lower than 150 m (Costa et al., 2004). These species seem
to have larger areas of distribution (e.g. A. alexandri, A.
elongatus, A. gymnoventris, A. luteoflammulatus, A.
monstrosus, A. prognathus, A. vazferrerae, A. wolterstorffi,
see Costa, 2006). So far A. paucisquama has been recorded
only from a temporary pool, without the proximity of a permanent water flow, in the altitude of 154 m and close to an area of
extensive use as pasture. This situation places the new species as a critically endangered species of Austrolebias.
Acknowledgments
Fig. 5. Temporary pool close to BR290 highway (30°22’27”S
53°33’42”W), type locality of Austrolebias paucisquama
(above) and detailed image of the vegetation coverage.
fishes collected in two collecting efforts in September 2004
and June 2005, corresponding to winter and autumn in the
southern hemisphere. Maximum depth observed was 50 cm.
The environment was almost completely covered with emergent vegetation, serving as cattle pasture.
Etymology. From the Latin “pauci” meaning few, and “squama”
meaning scales, in reference to the reduced number of scales
around caudal peduncle. A name in apposition.
Discussion
Austrolebias species are among the most endangered fish
species in the state of Rio Grande do Sul, Brazil. Eleven species of Austrolebias (one of these previously listed in the
genus Megalebias) are listed in the Red Book of endangered
species from the Rio Grande do Sul (Fontana et al., 2003),
corresponding to 39% of the fish species endangered in that
state. This is mostly related to the high endemism showed by
these species and the fact their preferential environments
suffer high impact by human use, mostly in agricultural activities.
The new species belongs to the A. alexandri species-
The authors thank Juan Anza, Júlia Giora and Adriana
Saccol Pereira that first collected the new species and
Conselho Nacional de Desenvolvimento Científico e
Teconológico – CNPq, Brazil (proc. 478002/2006-8 and 476821/
2003-7) for support.
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Accepted May 2008
Published June 28, 2008