Redescription of Allobates brunneus (Cope) 1887 (Anura: Aromobatidae: Allobatinae), with a description of the tadpole, call, and reproductive behavior
Author
Lima, Albertina P.
Author
Caldwell, Janalee P.
Author
Strussmann, Christine
text
Zootaxa
2009
1988
1
16
journal article
10.5281/zenodo.185498
5b318a88-0086-4e49-ab24-10ab445ddd2e
1175-5326
185498
Redescription of
Allobates brunneus
(
Figures
1–2
)
Adult definition and diagnosis:
A small-sized
Allobates
(mean adult male SVL
16.7 mm
; mean adult female SVL
18.3 mm
); dorsum granular, heaviest posteriorly; Finger I slightly longer than Finger II, Finger II longer than Finger IV; Finger III on males not swollen (
Fig.
3
A). Dorsolateral stripe absent in both sexes; ventrolateral stripes absent in preserved specimens, present in life; oblique lateral stripe present but diffuse (
Figs.
1
C and
1
F;
Figs.
2
A,
2
B, and
2
C); finger discs expanded; no webbing on hands (
Fig.
3
A); lateral fringes on fingers and toes absent (
Figs.
2
A and B); basal webbing present between Toes II and III and Toes III and IV (
Fig.
3
B); median lingual process absent (
Grant
et al
.
1997
); black arm-band absent (
Grant & Castro
1998
); white (unpigmented) testes extending half the length of the kidney; mature oocytes pigmented; teeth imperceptible under microscope at
50
X
magnification.
Comparison with other species:
Forty-four species are currently placed in the genus
Allobates
,
many of which are known only from the vicinity of their
type
localities or have restricted ranges. We distinguish
A. brunneus
from other species that occur in the Amazon region of
Brazil
or in southern
Brazil
.
Allobates brunneus
has a distinct dark hourglass pattern on the dorsum, which distinguishes it from
A. caeruleodactylus
(
Lima & Caldwell
2001
)
,
A. conspicuus
(
Morales
2002
“
2000
”),
A. fuscellus
(
Morales
2002
“
2000
”),
A. marchesianus
(
Melin
1941
;
Caldwell
et al
.
2002
b
),
A. masniger
(
Morales
2002
“
2000
”),
A. nidicola
(
Caldwell & Lima
2003
)
,
A. subfolionidificans
(
Lima
et al
.
2007
)
,
A
.
sumtuosus
(
Morales
2002
“
2000
”), and
A. vanzolinius
(
Morales
2002
“
2000
”), all of which have plain dorsa. It is distinguished from two other Amazonian species of
Allobates
that have hourglass patterns on the dorsum by the following characters:
A. crombiei
has Fingers II and IV equal in length, a distinct dorsolateral stripe, no oblique lateral or ventrolateral stripes, and throat dark gray in males (
Morales
2002
“
2000
”);
A. gasconi
is smaller than
A. brunneus
, dorsolateral and ventrolateral stripes are present, oblique lateral stripe is absent, and males have a swollen third finger and gray throat (
Morales
2002
“
2000
”).
Allobates olfersioides
(including synonyms
A. alagoanus
,
A. capixaba
and
A carioca
;
Lutz
1925
;
Verdade & Rodrigues
2007
) differs from
A. brunneus
in having a pattern of intercrossing Xs on the dorsum (dark hourglass pattern in
A. brunneus
) and no oblique lateral stripe (diffuse oblique lateral stripe extending from groin to near midbody in
A. brunneus
).
Adult description:
Females are slightly larger than males (
Table
1
). Average female SVL is
1.5 mm
greater than male SVL, but males have relatively wider heads [head wider than long; male HW
39
% of SVL in males,
37
% of SVL in females (t =
2.8
, df =
36
, P =
0.005
)]. Snout blunt, broadly rounded to nearly truncate in dorsal view (
Figs.
1
A and
1
D) and acutely rounded in lateral view (
Figs.
1
C and
1
F), extending past lower jaw (
Figs.
1
B and
1
E). Male SL
46
% and female SL
47
% of HL; IN in males and females
38
% of HW; EN in males
74
% and in females
73
% of HW; tympanic membrane inconspicuous, round, TYM
46
% of EL in both sexes; posterodorsal part of tympanum partially concealed by slip of m. depressor mandibulae; tongue attached anteriorly, longer than wide, slightly rounded posteriorly, median lingual process absent; teeth on premaxilla and maxilla imperceptible under light microscope at
50
X
magnification; dorsal skin granular, heavier posteriorly; dorsolateral stripe absent; ventrolateral stripe present in life, absent in preserved specimens; oblique lateral stripe present, consisting of a broad, diffuse area that interrupts the lateral dark brown band in several positions, most obvious from groin to midbody but extending to forearm in some specimens (
Figs.
1
and
2
).
TABLE 1.
Measurements (in mm) of adult males and females of
Allobates brunneus
collected from near the type locality. Abbreviations are defined in the text. Values are means ± standard deviation; maximum and minimum values are in parentheses.
| Character |
Male (n = 20) |
Female (n = 18) |
| SVL |
16.7 ± 0.8 (14.8–18.3) |
18.3 ± 1.2 (15.8–19.8) |
| HL |
4.6 ± 0.2 (42.2–5.0) |
5.0 ± 0.4 (4.2–5.6) |
| HW |
6.5 ± 0.5 (5.6–7.0) |
6.8 ± 0.4 (5.7–7.3) |
| SL |
2.1 ± 0.2 (1.8–2.3) |
2.4 ± 0.2 (1.9–2.7) |
| EN |
1.6 ± 1.0 (1.4–1.7) |
1.7 ± 0.1 (1.5–1.8) |
| IN |
2.4 ± 1.0 (2.3–2.7) |
2.6 ± 0.1 (2.3–2.9) |
| EL |
2.1 ± 0.2 (1.9–2.5) |
2.3 ± 0.2 (2.0–2.6) |
| IOD |
5.1 ± 0.3 (4.6–5.7) |
5.5 ± 0.3 (5.0–6.0) |
| TYM |
1.0 ± 0.1 (0.8–1.1) |
1.0 ± 0.1 (0.9–1.2) |
| FAL |
4.0 ± 0.3 (3.3–4.5) |
4.1 ± 0.2 (3.7–4.5) |
| HAND I |
3.3 ± 0.33 (2.6–4.1) |
3.3 ± 0.2 (2.9–3.7) |
| HAND II |
3.1 ± 0.3 (2.2–3.4) |
3.2 ± 0.2 (2.9–3.6) |
| HAND III |
4.2 ± 0.4 (3.2–4.7) |
4.4 ± 0.3 (3.7–5.0) |
| HAND IV |
2.8 ± 0.1 (2.6–3.0) |
2.9 ± 0.2 (2.6–3.1) |
| WFD |
0.5 ± 0.1 (0.4–0.6) |
0.6 ± 0.1 (0.4–0.7) |
| FL |
7.9 ± 0.5 (6.8–8.7) |
8.1 ± 0.5 (7.4–9.2) |
| WTD |
0.7 ± 0.1 (0.5–0.8) |
0.7 ± 0.1 (0.6–0.8) |
| TIL |
8.6 ± 0.5 (7.8–9.6) |
9.0 ± 0.2 (8.5–9.7) |
| AL |
3.7 ± 0.3 (3.2–4.2) |
3.9 ± 0.3 (3.5–4.3) |
Forearm slightly longer than upper arm; ulnar fold absent;
HAND
III length in males
19.5
% and females
18.4
% of SVL; Finger I slightly longer than Finger II when fingers appressed; Finger III>I>II>IV (
Fig.
3
A); finger webbing absent; palmar tubercle nearly round, diameter
0.65
±
0.08 mm
in females,
0.56
±
0.06 mm
in males,
14.1
% of HL in both sexes; thenar tubercle elliptic, one-third diameter of palmar tubercle (
Fig.
3
A); one subarticular tubercle present on Fingers I, II, and IV, two subarticular tubercles present on Finger III (
Fig.
3
A); basal subarticular tubercles on Fingers I and II largest, nearly equal in size, basal subarticular tubercle on finger IV very small; basal and distal subarticular tubercle on Finger III smaller, subequal. No fringes on fingers; all discs on fingers expanded; Finger III not swollen, width of disc on Finger III
0.55 mm
, disc
62
% wider than width of finger (hand characters in
Fig.
3
A).
FIGURE 1.
Dorsal (A), ventral (B), and lateral (C) view of male
Allobates brunneus
, INPA-H 10139; and dorsal (D), ventral (E), and lateral (F) view of female INPA-H 10119 in preservative.
FIGURE 2.
Dorsal views of males (A, B, and C) and females (D and E), showing variation in the dorsal patterns. (F) Ventral views of female (left) and male (right) in life showing the white throat in the female and the yellow throat in the male. (Photographs by A.P. Lima)
Hindlimbs robust; TL
50.4
% of SVL. Ratio of foot length to SVL in males (mean
0.47
±
0.02 mm
) significantly greater than in females (mean
0.45
±
0.03 mm
; t =
3.05
, df =
36
, P =
0.005
); foot length
45
% of SVL in males and
47
% in females; relative length of toes IV>III>V>II>I; basal webbing between Toes III and IV present in all specimens; rudimentary webbing present between Toes III and IV only in
5
of
38
specimens
; lateral fringes absent on all toes; Toe I reaching distal edge of subarticular tubercle of Toe II when appressed; discs on Toes I, II, III, and IV larger than adjacent phalanges; disc on Toe V nearly same width of phalanges; width of disc on toe IV
0.68 mm
in adults; inner metatarsal tubercle oval; outer metatarsal tubercle round; medial metatarsal tubercle absent; metatarsal fold weak, present in
33
and absent in
5
specimens
; tarsal keel distinct, short and curved; one subarticular tubercle on Toes I and II; two on Toes III and V; Toe IV with three subarticular tubercles, basal subarticular tubercle poorly defined in
33
and absent in
5
specimens
(foot characters in
Fig.
3
B).
FIGURE 3.
Ventral view of hand (A) and foot (B) of
Allobates brunneus
male INPA-H 10139.
Color in life:
Ground color of dorsum generally varies from light grayish brown to orange brown with one to three dark brown, sometimes diffuse, triangular, diamond, or hourglass markings from between the orbits extending to the sacral region (
Fig.
2
A–
2
C). Upper surface of arm light orange-brown; upper surfaces of legs light gray with dark brown transverse bands on thigh, shank and foot in most specimens. Adult males with greenish-yellow throats with melanophores evenly dispersed on vocal sac; chest and belly lemon yellow to light lemon yellow; adult females yellow on outer edge of throat becoming white on central part of throat, blending with white chest and belly (
Fig.
2
D). Flank and undersurface of thigh greenish yellow; undersurface of leg and foot light gray; lower surface of arm light brown. Dorsolateral stripe absent; oblique lateral stripe pale tan to light orange brown, forming diffuse area variously extending from groin to midbody or sometimes to arm insertion; ventrolateral stripe consisting of a series of irregular, elongate white spots, extending from the anterior corner of eye to groin. Upper part of iris and pupil ring metallic gold with fine black reticulations; remainder of iris brown.
Color in preservative:
Ground color of dorsum uniform light brown with
1 to 3
chocolate brown triangular, diamond-shaped, or hourglass markings extending from between the orbits to the sacral region (
Figs.
1
A and
1
D); upper surface of arms cream to yellowish in
35
specimens
, brown in
3
; posterior surfaces of arms and legs light brown with dark brown flecks. In
35
specimens
, upper surfaces of leg light brown with a dark brown band on thigh, shank, and foot; in
3
specimens
these bands diffuse. Dark brown band extending from the snout laterally around the body, to midbody in
35
specimens
, or nearly to arm insertion in
3
specimens
; this lateral dark brown band narrows before and after eye. Ventrolateral stripe not visible in preserved specimens; pale oblique lateral stripe interrupts lateral dark brown band at midbody in
32
specimens
; in
6
specimens
it consists of diffuse pale cream spots imbedded in the dark brown lateral band at level of groin (
Fig.
1
C and
1
F,
2
A–
2
C). Flank, belly, and upper lip plain white or very light yellow; adult male throat cream to yellowish with rows of spots formed by melanophores around lips; widely dispersed melanophores visible only under microscope on remainder of throat; chest and belly cream to yellowish (
Fig.
1
B). Female throat, chest, and belly cream (
Fig.
1
E); palms of hands and soles of feet brown; paracloacal mark absent (
Fig.
1
A–
1
F).