A new annual fish of the genus Simpsonichthys (Cyprinodontiformes: Cynolebiidae) from the upper Rio Jequitinhonha basin, Brazil
Author
Nielsen, Dalton Tavares Bressane
Author
Pessali, Tiago Casarim
Author
Dutra, Guilherme Moreira
text
Zootaxa
2017
4263
1
165
172
journal article
33094
10.11646/zootaxa.4263.1.8
c9c0aa57-d54c-47ed-931b-b0252a9d5054
1175-5326
572603
EB901E55-4E66-428A-B5E6-C9A5238208FC
Simpsonichthys espinhacensis
,
new species
(
Figs. 1–2
;
Table 1
)
Holotype
.
MCNIP
1792,
45.7
mm SL,
Brazil
,
Minas Gerais
,
Olhos D
´água,
Vereda Volta da Capoeira
, tributary of
Ribeirão da Areia
,
Rio Jequitinhonha
basin,
17°15'29.54"S
43°43'10.10"W
, 0
8 Feb 2016
,
T. C. Pessali
&
T. A. Barroso.
Paratypes.
All
from
Brazil
,
Minas Gerais
,
Olhos D
´água,
Rio Jequitinhonha
basin:
MCNIP
1681, 4
+5CS,
18.2–43.6 mm
SL, collected with
holotype
.
MCNIP
1685, 2
, 27.6–38.0 mm SL, same locality as holotype,
20 Aug 2014
,
T. J. Sousa
and
B. Andreata
. MCNIP 1686, 8,
18.3–25.8 mm
SL, Ribeirão da Areia, 17°17'32.02"S 43°39'44.50"W, 0
8 Feb 2016
, T. C. Pessali & T. A. Barroso.
MPEG
34050, 2
+2CS,
22.7–30.9 mm
SL, same locality as holotype, 0
7 Jan 2016
,
T. C. Pessali
&
A. A. Rodrigues
. MZUSP
120736
, 2,
21.3–30.9 mm
SL, collected with holotype. ZUEC 13430, 1,
21.3 mm
SL, collected with holotype.
ZUEC
13479, 1
,
35.8 mm
SL, same locality as holotype,
20 Aug 2014
,
T. J. Sousa
&
B. Andreata.
Diagnosis.
Simpsonichthys espinhacensis
is distinguished from all congeners by the frontal squamation Apatterned (
versus
E-patterned). Males of
S. espinhacensis
also differ from all congeners by the color pattern of body, reddish brown with light blue dots on each scales in males (
versus
red bars alternating with light blue bars in
S. cholopteryx
,
S. nigromaculatus
and
S. parallelus
; or series of longitudinal light blue dots in
S. boitonei
,
S. margaritatus
,
S. punctulatus
,
S. santanae
, and
S. zonatus
); the absence of contact organs at the pectoral fin (
versus
presence); and the presence of scales on anal-fin base (
versus
absence).
Simpsonichthys espinhacensis
further differs from
S. boitonei
,
S. punctulatus
,
S. santanae
, and
S. zonatus
by the iris red (
versus
light yellow) and posterior margin pectoral fin reaching the 1st or 2nd anal fin rays (
versus
4th to 6th in
S. boitonei
and
S. zonatus
; 4th to 7th in
S. punctulatus
and
S. santanae
). The new species additionally can be diagnosed from
S. boitonei
and
S. punctulatus
by the caudal fin length, 20.3–27.6% of SL (
versus
35.8–40.6% of SL and 40.8–41.3% of SL, respectively).
Simpsonichthys espinhacensis
can be further distinguished from
S. punctulatus
and
S. zonatus
by the eye diameter, 22.0–27.5% of HL (
versus
34.7–35.0% of HL and 29.9–34.7% of HL, respectively).
Females of
S. espinhacensis
can be distinguished from all congeners by presenting the tip of pectoral fin reaching vertical anterior to pelvic fin (
versus
vertical at urogenital papillae or anus).
Description.
Morphometric data presented in
Table 1
. Largest male specimen examined
45.7 mm
SL, largest female
34.4 mm
SL. Dorsal profile convex from snout to end of dorsal-fin base, approximately straight along caudal peduncle. Ventral profile slightly convex from tip of jaw to origin to end of anal-fin base, approximately straight along caudal peduncle. Body moderately deep, compressed, greatest body depth at vertical slightly ahead of anal fin origin.
TABLE 1.
Morphometric data from the type-series of
Simpsonichthys espinhacensis
. Range of males includes values for the holotype.
Males Females
Holotype
Range N Mean SD Range N Mean SD Head compressed, greatest depth at nape. Snout blunt. Mouth superior. Premaxillary teeth 33(1) or 37(1). Dentary teeth 40(1) or 43(1). Vomerine teeth absent. Eye positioned on sides of head. Branchial membranes joined at isthmus. Gill-rakers on first brachial arch 2+9(1) or 3+9(1). Branchiostegal rays 6(7). Urogenital papilla cylindrical and small in males, pocket-shaped in females.
45.7 |
20.6–45.7 |
13 |
- |
- |
18.2–34.4 |
12 |
- |
- |
Percent of stardard length
|
Body depth |
32.6 |
30.2–33.9 |
13 |
31.8 |
1.0 |
26.7–33.4 |
10 |
30.8 |
2.0 |
Caudal peduncle depth |
14.9 |
12.1–15.1 |
13 |
14.0 |
1.1 |
12.2–15.0 |
10 |
13.9 |
0.8 |
Predorsal length |
52.7 |
52.7–63.1 |
13 |
57.7 |
2.4 |
61.8–67.7 |
10 |
64.1 |
1.5 |
Prepelvic length |
46.2 |
46.2–54.3 |
13 |
50.7 |
2.3 |
48.9–54.5 |
9 |
52.4 |
2.3 |
Length of dorsal-fin base |
27.6 |
24.8–30.7 |
13 |
28.0 |
1.8 |
18.1–23.5 |
10 |
20.0 |
1.7 |
Length of anal-fin base |
25.7 |
21–28.6 |
13 |
25.2 |
2.2 |
17.4–22.3 |
10 |
19.0 |
1.5 |
Caudal-fin length |
21.7 |
20.3–29.5 |
12 |
24.4 |
2.8 |
21.9–25.4 |
9 |
23.2 |
1.2 |
Pectoral-fin length |
20.8 |
18.3–25.0 |
13 |
20.5 |
2.1 |
18.8–22.1 |
10 |
20.6 |
1.0 |
Pelvic-fin length |
6.6 |
6.4–8.8 |
13 |
7.2 |
0.8 |
3.9–6.7 |
10 |
4.9 |
0.9 |
Head length |
30.2 |
25.6–33.9 |
13 |
30.2 |
2.3 |
28.1–33.9 |
10 |
31.3 |
2.2 |
Percent of head length
|
Head depth |
94.3 |
89.2–94.5 |
12 |
91.0 |
2.1 |
77.8–86.2 |
10 |
81.7 |
3.5 |
Head width |
68.8 |
64.6–71.2 |
11 |
67.9 |
2.4 |
66.4–67.4 |
8 |
66.9 |
0.4 |
Snout length |
12.9 |
12.4–13.7 |
11 |
13.0 |
0.4 |
12.4–13.1 |
8 |
12.7 |
0.3 |
Lower jaw length |
17.6 |
17.1–18.9 |
11 |
17.9 |
0.6 |
14.9–15.4 |
8 |
15.2 |
0.2 |
Eye diameter |
22.6 |
22–27.5 |
13 |
25.6 |
1.6 |
26.4–31.2 |
10 |
28.8 |
1.9 |
Pectoral fin elliptical with 13*(22) or 14(6) rays. Posterior margin reaching vertical between insertion of 1st or 2nd anal-fin rays in males, and anterior to pelvic fin in females. Dorsal fin filamentous in males and rounded in females. Dorsal-fin with 16(1) or 18*(14) rays in males, and 14(4), 15(5), 16(2), or 18(2) in females. Dorsal fin rays in males gradually increasing in size, 13rd to 15th rays larger than remaining, 16th to 18th rays gradually decreasing in size. Dorsal-fin origin at vertical posterior to anal fin origin, between 2nd or 3rd anal-fin rays in males and females. Dorsal fin with 18(3) pterygiophores in males and 16(4) in females. First pteryogiophore between to neural spine of 9th and 10th vertebrae in males, and 10th and 11th vertebrae in females. Pelvic fin short and pointed with 5(6) or 6*(18) rays. Posterior margin reaching 2nd or 3rd anal-fin rays in males, and vertical between anus and urogenital papilla in females. Pelvic-fin base with interspace. Anal fin filamentous in males and rounded in females. Anal fin with 16(2), 17(4), 18*(19) or 19(3) rays. Anal-fin rays in males gradually increasing in size, 13rd to 15th rays larger than remaining, 16th to 19th rays gradually decreasing in size. Anal fin with 18(2) pterygiophores, first one between 8th or 9th pleural ribs in males, and 9th or 10th in females. Caudal fin rounded, with 22(1), 24(2), 25(2), 27(2) or 28*(21) rays.
FIGURE 1.
Lateral view of
Simpsonichthys espinhacensis
, holotype, MCNIP 1792, male, 45.7 mm SL; Brazil, Minas Gerais State, Vereda Volta da Capoeira, Rio Jequitinhonha basin. A) Live specimen photographed in aquarium; B) same specimen after preservation.
FIGURE 2.
Lateral view of
Simpsonichthys espinhacensis
, paratype, MPEG 34050, female, 26.0 mm SL; Brazil, Minas Gerais State, Vereda Volta da Capoeira, Rio Jequitinhonha basin. A) Live specimen photographed in aquarium; B) Same specimen after preservation.
Scales large, cycloid. Body and head entirely scaled. Frontal squamation A-patterned. Supraorbital scales absent. Longitudinal series with 25(1), 26(1), 27*(15) or 28(5) scales. Transversal series of scales from dorsal-fin origin to pelvic-fin origin 10*(20) or 11(3). Single row of scales on basal portion of anal fin. Circumpeduncular scales 12(2), 13(1) or 14*(19). Males presenting five rows of minute contact organs on each scale on head and flanks, reaching vertical through end of anal fin. Contact organs absent at pectoral fin in males.
Cephalic neuromasts: supraorbital 15–16, parietal 3, anterior rostral 3, posterior rostral 3, infraorbital 2 + 16– 18, preorbital 2, otic 2, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 12–14, mandibular 12, lateral mandibular 2–3. Two neuromasts on caudal fin base. Total vertebrae 26(3) or 27(4). Pleural ribs 10(2).
Coloration in life—males.
Based on the picture of the
holotype
(
Fig. 1
A). Overall background color of trunk and head reddish brown. All scales with a small metallic light blue dot in center. Ventral portion of head metallic gold. Tip of jaw and snout light brown. Circumorbital area reddish brown. Iris red with vertical black bar through middle of eye. Head with horizontal dark brown line ventrally from posterior first row of scales to preopercular region; then vertically to horizontal through dorsal portion of eye; posteriorly from that point to postero-dorsal portion of opercle; and vertically along posterior margin of opercle.
Pectoral fin hyaline. Dorsal fin reddish brown, with alternate light yellow elongated spots on anterior portion; posterior portion with rows of greenish blue rounded spots. Pelvic fin darkened. Anal fin reddish brown, with alternate hyaline bars on inter-radial membranes; tip of elongated anal-fin rays light black. Caudal fin reddish brown, with light blue dots along inter-radial membranes.
Coloration in life—females.
Overall background color of trunk and yellowish brown (
Fig. 2
A). Flank with series of one to four vertically elongated black blotches. First to third blotches anterior to dorsal fin insertion and fourth on the middle of caudal peduncle. Overall background color of head yellowish brown, becoming progressively lighter ventrally. Iris light yellow with vertical black bar through middle of eye. Opercular region pale golden green. All fins hyaline.
Distribution and habitat.
Known only from Vereda Volta da Capoeira and Ribeirão da Areia, headwater (775–800 meters a.s.l.) tributaries of the Rio Jequitinhonha basin,
Minas Gerais
state,
Brazil
(
Fig. 3
). These are large flooded areas during the rainy season (
Fig. 4
A, D). During this time of the year, water is relatively cold (24.6– 26.9°C), with
pH
ranging from 6.46 to 7.38, electric conductivity 0.04 to 0.47 mS/cm, and water salinity 0.02 to 0.23 ppt. The soil is hydromorphic with a thick layer of organic matter. During the dry season, the wetland is reduced to small pools and intermittent channels (
Fig. 4
C). The wetlands are dominated by herbaceous and grassy vegetation, with buriti palms (
Mauritia flexuosa
) (
Fig. 4
D).
Simpsonichthys espinhacensis
occurs sympatrically with
Astyanax
aff.
fasciatus
,
Astyanax
cf.
lacustris
,
Astyanax
sp.,
Characidium
spp.,
Coptodon rendalli
,
Corydoras
sp.,
Cyphocharax jagunco
,
Hasemania
sp.,
Hoplias brasiliensis
,
Rhamdia
aff.
quelen
and
Synbranchus
sp.
FIGURE 3.
Map of eastern portion of South America, showing the distribution of
Simpsonichthys espinhacensis
(black star). The symbol represent more than one locality.
Etymology.
The specific epithet is in reference to the Serra do Espinhaço, which was declared in 2005 a Biosphere Reserve by the United Nations Educational, Scientific and Cultural Organization (UNESCO) by its natural heritage (
Andrade & Domingues, 2012
). The name “Serra do Espinhaço” (“Backbone range”) was proposed in 1822 by W. L. von Eschwege in allusion to the subsequent, longitudinally slender North-South oriented plateaus, whose shape resembles a vertebral column (
Derby, 1906
).
Conservation status
. The estimated area of occupancy of
Simpsonichthys espinhacensis
is
0.650 km
2. The known area of occurrence of
S. espinhacensis
has been progressively degraded by fire, water catchment, construction of embankments, and deforestation for eucalyptus plantations and cattle (
Fig. 4
E–F). Considering the present relevant threats to the species,
Simpsonichthys espinhacensis
could be classified as Critically Endangered (CR), according to the International Union for Conservation of Nature (IUCN) categories and criteria (
IUCN Standards and Petitions Subcommittee, 2016
). Conservation measures needed for
S. espinhacensis
are the recovery of wetlands and the restriction of forestry activities in the area. However, enforcement of environmental laws by governmental agencies in the upper Jequitinhonha basin area is badly needed.
Remarks.
The inclusion of the new species within
Simpsonichthys
is justified by the presence of all three synapomorphies recognized for that genus by
Costa (2006)
: minute or absent pelvic fins, a reduced mesopterygoid, and the presence of five alternating bright blue and pink to red bars on head sides in males. The inclusion of the new species in the genus
Simpsonichthys
is further justified by the ventral process of posttemporal minute or absent and the flanks of males predominantly pink to red. These two latter features are also found in other genera of
Cynolebiidae (
Costa, 2006
)
.
The genus
Simpsonichthys
is divided into two clades with separate and well defined geographical areas (
Costa, 2010
). The species belonging to the eastern clade differ from the ones belonging to the western clade by the body size (near
40 mm
SL
versus
near
25 mm
SL), caudal fin without dark margin and subdistal blue line on caudal fin (
versus
presence of such coloration pattern), a distal stripe on dorsal and anal fins (
versus
dark gray distal stripes), pectoral fin reddish hyaline in males (
versus
hyaline), and presence of filaments in dorsal and anal fins in males (
versus
absence) (
Costa, 2006
,
2007
).
Simpsonichthys espinhacensis
presents all the characters described for the eastern clade, and consequently is considered herein as belonging to it.