Revision of the Neotropical trahiras of the Hoplias lacerdae species-group (Ostariophysi: Characiformes: Erythrinidae) with descriptions of two new species
Author
Oyakawa, Osvaldo T.
Author
Mattox, George M. T.
text
Neotropical Ichthyology
2009
2009-06-30
7
2
117
140
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252009000200001&lng=en&tlng=en
journal article
10.1590/S1679-62252009000200001
1982-0224
5420421
0041B40D-74DE-41E3-B245-0D3B36B695F2
Hoplias intermedius
(
Günther, 1864
)
Fig. 8
Erythrinus brasiliensis
: -
Castelnau, 1855:56
[misidentification, occurrence in the rio Carandaí, rio
Paraná
drainage, differences from
Erythrinus trahira
].
Macrodon intermedius
Günther, 1864: 282
[original description; type locality: rio Cipó,
Minas Gerais State
,
Brazil
;
syntypes
: BMNH 1861.5.16.6-7, dried and stuffed specimens]. -
Steindachner, 1874: 26
[species list as synonym of
Macrodon trahira
]. -
Eigenmann & Eigenmann, 1889: 103
[species list as synonym of
Macrodon malabaricus
]. -
Eigenmann, 1910: 448
[species list as synonym of
Hoplias malabaricus
]. -
Fowler, 1950: 364
[species list, synonym of
Hoplias malabaricus malabaricus
]. -
Godoy, 1975: 406
[synonym of
Hoplias malabaricus malabaricus
]. -
Lütken, 2001: 78
[as synonym of
Macrodon trahira
]. -
Oyakawa, 2003: 239
[as synonym of
Hoplias microcephalus
].
Hoplias lacerdae
: -
Britski, 1972: 81-82
[in part, species list, differences from
H
.
malabaricus
, occurrence in the rio
Paraná
basin]. -
Bertollo
et al
., 1978
[occurrence in upper rio Grande, upper
Paraná
, karyotype description]. -
Bizerril, 1994: 56
[in part, occurrence in rios
Paraná
and São Francisco]. -
Penczak
et al
., 1998: 92
[occurrence in the rio Ivaí, rio
Paraná
basin]. -Agostinho & Júlio Jr., 1999: 382 [occurrence in upper rio
Paraná
]. -
Meschiatti
et al
., 2000: 135
[occurrence of juveniles in floodplains of rio Mogi- Guaçú, upper
Paraná
]. -Alves & Pompeu, 2001 [occurrence in upper rio São Francisco]. -Barrella & Petrere Jr., 2003: 65 [occurrence in the rio Tietê basin, upper rio
Paraná
]. - Pompeu & Alves, 2003: 133 [hypothesis of introduction into the rio São Francisco basin]. -Alvim & Peret, 2004: 198 [diet in the rio São Francisco]. -
Vieira
et al
., 2005: 80
[occurrence in upper reaches of rios São Francisco and Doce]. -Cunico & Agostinho, 2006: 128 [occurrence in tributary to rio Ivaí, rio
Paraná
basin]. -
Silva
et al
., 2006a: 832
[occurrence in the rio São Francisco]. -
Silva
et al
., 2006b: 3572
[occurrence in the rio Tietê, upper rio
Paraná
].
Fig. 8.
Hoplias intermedius
, MZUSP
69370, 169.3 mm SL, rio Suaçui Pequeno, Minas Gerais State, Brazil.
Hoplias
cf.
lacerdae
: -
Britski
et al.,
1984:55
[identification key, occurrence in Três Marias Dam, rio São Francisco drainage].
Hoplias
aff.
lacerdae
: -Sato & Godinho, 1999:411 [occurrence in the rio São Francisco basin].
Lectotype
.
BRAZIL
.
Minas Gerais State
.
São Francisco
basin:
BMNH 1861.5
.16.6,
533.4 mm
SL,
rio Cipó
, no date,
Ch. Cumberland. Dry
and mounted specimen (
Fig. 9
), [designated herein].
Paralectotype
.
BRAZIL
.
Minas Gerais State
.
São Francisco
basin:
BMNH 1861.5
.16.7,
279.4 mm
SL, same locality and collector. Skin [designated herein]
.
Material examined.
BRAZIL
.
Bahia State
.
São Francisco basin:
MZUSP
94050, 1,
73.5 mm
SL, rio Formoso, tributary to rio Corrente, Colônia do Formoso;
MZUSP
94434, 15,
17.6-181.7 mm
SL, riacho do Morro Furado, tributary to rio Corrente near mouth of Gruta do Morro Furado, Coribe;
MZUSP
94667, 2,
14.8-27.7 mm
SL, riacho do Morro Furado, tributary to rio Corrente, Coribe;
MZUSP
94436, 2, 284.2-
309.8 mm
SL;
MZUSP
94437,
1, 284.9 mm
SL, Sobradinho Dam, rio São Francisco.
Minas Gerais State
.
São Francisco basin:
INPA
26894, 4, 242.7-282.0 mm SL;
MCP
13994,
1, 448.4 mm
SL;
MCP
13995,
1, 367.2 mm
SL;
MZUSP
24638, 3, 275.8-
374.4 mm
SL;
MZUSP
38639, 10, 235.8-
349.3 mm
SL, Três Marias Reservoir, rio São Francisco;
MZUSP
38052, 1,
58.9 mm
SL, Três Marias Reservoir near Morada Nova de Minas;
MCP
14091, 1, 392.0 mm SL;
MCP
14092,
1, 420.2 mm
SL;
MCP
14102, 1, 401.0 mm SL; rio São Francisco between Três Marias and Pirapora;
MZUSP
1495,
1, 146.6 mm
SL, rio São Francisco, Pirapora;
MZUSP
25062, 1,
47.9 mm
SL, córrego do Julião, on the road to Jaboticatubas;
MZUSP
37157, 9,
35.3-47.7 mm
SL, stream tributary to rio Paraopeba, Moeda;
MZUSP
37252, 3, 130.4-
162.7 mm
SL, lagoa da Prata, rio São Francisco;
MZUSP
38571, 2, 375.5-
377.8 mm
SL, córrego Água Limpa, tributary to rio Abaeté;
MZUSP
39239, 1, 20.0 mm SL, lagoon on right bank of córrego Braço Grande, rio São Francisco;
MZUSP
39275, 1, 105.0 mm SL, Ilha Grande, rio São Francisco;
MZUSP
39381, 2,
16.4-53.2 mm
SL, lagoa do Praiano, left bank of rio São Francisco;
MZUSP
39565,
1, 102.6 mm
SL, córrego Ribeiro Manso, tributary to rio Abaeté;
MZUSP
39571, córrego Água Limpa, tributary to rio Abaeté;
MZUSP
39628,
1, 127.2 mm
SL, córrego Capivara, tributary to rio Abaeté;
MZUSP
39652, 2, 140.1-
196.9 mm
SL, córrego Chumbo, tributary to rio Abaeté;
MZUSP
39700,
1, 240.8 mm
SL, rio São Francisco at Pontal do Abaeté;
MZUSP
39741, 4, 169.8-
265.9 mm
SL, rio São Francisco and tributaries, Formoso Hydroelectric Station area;
MZUSP
39779, 1,
22.5 mm
SL, rio São Francisco at mouth of rio Formoso;
MZUSP
47268, 2,
42.6-128.2 mm
SL, stream under bridge of
BR
135 road, between Corinto and Augusto de Lima;
MZUSP
47325, 1,
67.8 mm
SL, stream tributary to rio Jequitaí, on
BR
135 road, between Buenópolis and Engenheiro Dolabela;
MZUSP
54696, 2,
40.5-42.1 mm
SL, rio Cipó, circa
10 km
southeast of
BR
259 road, Presidente Juscelino;
MZUSP
73655,
1, 105.7 mm
SL, rio Cipó, Presidente Juscelino;
MZUSP
73735,
1, 164.2 mm
SL, rio Bicudo, Fazenda Bom Jardim, Corinto;
MZUSP
73837,
1, 249.9 mm
SL, Lagoa Santa, rio das Velhas drainage;
MZUSP
73839,
1, 274.8 mm
SL, rio Curimataí, Fazenda Vitória, Augusto de Lima;
MZUSP
73842,
1, 259.9 mm
SL, central lagoon in Lagoa Santa;
MZUSP
79247, Gruta Morena, Cordisburgo;
MZUSP
86019, 1,
73.8 mm
SL, rio Verde Grande, Montes Claros;
MZUSP
94433, 2, 45.0-
52.2 mm
SL, lagoa Azul, rio das Velhas Basin, Cordisbugo;
MZUSP
94435, 6,
34.2-257.2 mm
SL, ribeirão da Onça, tributary to rio das Velhas, Cordisburgo;
Minas Gerais State
.
Jequitinhonha basin:
MZUSP
38830, 3, 147.3-
221.7 mm
SL, rio Araçuai downstream from the rio Fanado, Santa Rita.
Minas Gerais State
.
Doce basin:
MZUSP
74659, 1,
29.6 mm
SL, rio Guanhães, Dores de Guanhães;
MZUSP
75289, 2, 27.5-68.0 mm SL, rio Santo Antônio, Fazenda Campinas, Conceição do Mato Dentro;
MZUSP
75331,
1, 276.7 mm
SL, rio Santo Antônio, Santo Antônio;
MZUSP
73113,
1, 313.4 mm
SL, córrego da Fonseca, rio Santo Antônio,
11 km
from Santo Antônio, São Sebastião do Rio Preto;
MZUSP
75357,
1, 160.1 mm
SL, rio Santo Antônio, Santo Antônio;
MZUSP
80937, 1, 355.0 mm SL, rio Tronqueiras, São José de Tronqueiras near border with Coroací, Governador Valadares;
MZUSP
69329, 2,
21.1-25.9 mm
SL, rio Suaçuí Pequeno upstream from waterfall, Coroaci;
MZUSP
69357, 2,
17.3-25.4 mm
SL, rio Suaçuí Pequeno, upstream from and near the bridge of Procópio, Coroaci;
MZUSP
69370,
1, 169.3 mm
SL, rio Suaçuí Pequeno, downstream from the bridge of Procópio, Coroaci;
MZUSP
66196, 2,
28.1-89.6 mm
SL, rio Suaçuí Grande, downstream from the Traíra II Hydroelectric Station, Peçanha;
MZUSP
87813,
1, 102.1 mm
SL, stream tributary to rio Santo Antônio, Serro;
MZUSP
87816,
1, 172.4 mm
SL, small waterfall in córrego Claudiano, tributary to rio do Peixe, rio Santo Antônio drainage, Serro;
MZUSP
87824, 1.
71.1 mm
SL, Cachoeira do Cancão, rio Mãe d’Água, tributary to rio Santo Antônio, Santo Antônio do Itambé.
Minas Gerais State
.
Paraíba
do Sul basin:
MZUSP
81011, 2, 248.7-
267.2 mm
SL, rio Glória, tributary to rio Muriaé, Muriaé, rio
Paraíba
do Sul basin.
Minas Gerais State
.
upper
Paraná
basin:
MZUSP
44019,
1, 116.7 mm
SL, Camargos Reservoir, rio Grande, São João del Rei;
MZUSP
51460, 4, 201.5-
277.5 mm
SL, rio Grande, Itutinga Hydroelectric Station;
MZUSP
51469,
1, 142.5 mm
SL, rio Pará, Cajuru Hydroelectric Station, Carmo do Cajuru;
MZUSP
51994, 4, 140.1-
290.6 mm
SL, Camargos Reservoir, rio Grande;
MZUSP
38638,
1, 312.1 mm
SL, rio Paranaíba,
Bocaina Hydroelectric
Station.
São Paulo State
.
upper
Paraná
basin:
MZUSP
23006, 2, 252.8-
430.5 mm
SL;
MZUSP
24827, 23, 135.2-
322.9 mm
SL;
MZUSP
45580, 1, 315.0 mm SL, rio Pardo, Limoeiro Hydroelectric Station, São José do Rio Pardo.
Paraná State
.
upper
Paraná
basin:
MZUSP
38570,
1, 113.6 mm
SL, mouth of rio Cantú, tributary to rio Piquirí, Campina da Lagoa;
MZUSP
39780, 2, 171.8-
245.8 mm
SL, rio Piquirí, Campina da Lagoa.
Diagnosis.
Hoplias intermedius
differs from the others species of the
H
.
lacerdae
group, but
H
.
australis
and
H
.
lacerdae
, in the number of scales along lateral line (42-46
vs
.
38-43 in
H
.
brasiliensis
and
34-39 in
H
.
curupira
). It can be further distinguished from
H
.
australis
and
H
.
lacerdae
, in the number of pores of the laterosensory system along the ventral surface of dentary (4-6
vs
. always 5 and 6-8 respectively). The shape of anterior profile of head further distinguished
H
.
intermedius
from
H
.
australis
(angular
vs
. rounded respectively).
Description.
Morphometric data presented in
Table 6
. Body cylindrical, deeper than wide. Greatest body depth at vertical through fifth scale anterior to dorsal-fin origin in specimens smaller than
40 mm
SL, closer to dorsal-fin origin in larger specimens. Anterior profile of head rounded in lateral view in specimens smaller than
40 mm
SL, more angular in larger specimens. Dorsal profile of head varying from slightly convex in specimens smaller than
40 mm
SL to gradually becoming straighter in larger specimens. Dorsal margin of orbit located at horizontal through of dorsal profile of head in specimens smaller than
130 mm
SL, but not reaching dorsal profile of head in larger specimens (
ca
.
300 mm
SL). Dorsal profile of body slightly convex from vertical through first series of scale of body to dorsal-fin origin; straight and posteroventrally inclined along dorsal-fin base; straight and less inclined to slightly concave from vertical through base of last dorsal-fin ray to origin of dorsal most procurrent caudal-fin ray. Ventral profile of lower jaw distinctly angular in region of mandibular symphysis, straight to slightly inclined from vertical through anterior nostril to posterior margin of lower jaw. Medial margins of contralateral dentaries running in parallel (
Fig. 1
a-c). Ventral profile of body slightly convex to pelvic-fin origin; approximately straight to slightly convex from latter point to anal-fin origin; straight and posterodorsally inclined along anal-fin base; slightly concave from base of last anal-fin ray to anterior most ventral procurrent caudal-fin ray.
Table 6.
Morphometric data of
Hoplias intermedius
. Standard length in mm; values 1-14 are percents of standard length and values 15-22 are percents of head length. n = number of examined specimens.
n |
Mean |
Range |
Standard deviation |
Standard length |
99 |
- |
16.4-448.4 |
- |
1. Body depth |
95 |
20.8 |
15.3-26.5 |
2.5 |
2. Head length |
99 |
31.4 |
28.8-36.9 |
1.8 |
3. Pectoral-fin length |
90 |
18.4 |
16.2-22.3 |
1.2 |
4. Pelvic-fin length |
98 |
18.9 |
15.3-22.4 |
1.2 |
5. Anal-fin length |
98 |
18.2 |
13.6-25.1 |
1.5 |
6. Dorsal-fin length |
99 |
28.5 |
23.6-33.7 |
1.9 |
7. Dorsal-fin base |
99 |
16.8 |
13.4-20.5 |
1.2 |
8. Anal-fin base |
99 |
9.2 |
7.3-11.5 |
0.8 |
9. Pre-pectoral distance |
98 |
29.0 |
24.8-36.2 |
2.4 |
10. Pre-pelvic distance |
99 |
55.7 |
50.0-61.7 |
1.6 |
11. Pre-dorsal distance |
99 |
50.5 |
46.3-56.0 |
2.1 |
12. Pre-anal distance |
99 |
81.1 |
72.8-87.2 |
2.4 |
13. Caudal-peduncle depth |
98 |
13.6 |
9.6-15.4 |
1.2 |
14. Caudal-peduncle length |
99 |
13.4 |
10.1-15.3 |
1.1 |
15. Head depth |
99 |
42.2 |
34.5-48.8 |
2.5 |
16. Snout length |
98 |
24.2 |
15.3-28.4 |
2.4 |
17. Snout width |
97 |
18.9 |
12.6-22.1 |
2.1 |
18. Snout depth |
97 |
19.7 |
10.3-24.2 |
2.6 |
19. Pre-nasal distance |
97 |
14.8 |
9.5-19.3 |
2.0 |
20. Orbital diameter |
98 |
20.9 |
13.7-35.8 |
5.4 |
21. Interorbital width |
99 |
22.2 |
15.1-28.0 |
2.8 |
22. Upper jaw length |
99 |
47.5 |
39.1-57.9 |
2.9 |
Upper and lower jaws of similar size in specimens smaller than
40 mm
SL, upper jaw gradually becoming shorter than lower jaw in larger specimens. Posterior portion of maxilla dorsally enlarged and extending medial to anterior margins of second and third infraorbitals. Upper and lower lips fleshy with short projections of skin covering canines externally. Anterior nostril tubular with anterior slit along its distal half. Anterior and posterior nostrils situated along horizontal through center of orbit, anterior nostril located at two-thirds of orbital diameter from anterior margin of orbit; posterior nostril situated midway between anterior nostril and anterior margin of orbit. Eye proportionately larger in smaller specimens. Infraorbital bones well-developed and horizontally elongate. Infraorbitals 3, 4, and ventral portion of 5 partially covering preopercle. Anteroventral margin of infraorbital 3 relatively straight and posteroventral margin convex. Posterior margin of infraorbitals 4, 5, and 6 slightly convex. Small specimens (
ca
.
40 mm
SL) with infraorbital 3 barely reaching orbital rim and proximal ends of infraorbitals 2 and 4 almost in contact. Larger specimens (
ca
.
130 mm
SL) with infraorbitals 3 and 4 completely excluded from orbital rim and infraorbital 5 progressively separated from rim in larger specimens. Proximal ends of infraorbitals 2 and 6 almost meeting in some of the largest specimens examined (
ca
.
300 mm
SL).
Teeth in both jaws conical or canine. Premaxillary teeth in single row. First premaxillary tooth large canine, second and seventh teeth medium sized. Eighth tooth canine almost as large as anterior most premaxillary canine. Third to sixth, and ninth premaxillary teeth small. Maxillary with single row of approximately 32 relatively small teeth, except for very well developed canine-like fourth tooth. Dentary with anterior external row of teeth and posterior internal row. External series with three anterior small teeth, followed by two well developed canines with posterior canine larger than anterior canine, and then 11 conical teeth slightly smaller than anterior most dentary canine. Internal series beginning at level of last conical tooth of external row and composed of approximately 18 very small teeth. Accessory ectopterygoid and ectopterygoid toothed. Ectopterygoid with series of small conical teeth along ventrolateral margin and many smaller viliform teeth on ventromedial surface. Endopterygoid edentulous.
Distal margins of all fins rounded. Total dorsal-fin rays 13-15 (n = 98; ii,11-13; mode: ii,12, n = 44). Dorsal fin located at midbody, its origin at vertical through approximately fourth scale anterior on series along pelvic-fin origin. Longest dorsalfin ray approximately three-quarters of body depth. Anal-fin base short. Total anal-fin rays 9-11 (n = 97; ii,7-9; mode: ii,8, n = 88). Tip of depressed dorsal fin reaching vertical through anal-fin origin in small specimens (<
130 mm
SL) but falling short of that point in larger specimens. Total pectoral-fin rays 12-14 (n = 89; i,11-13; mode: i,11, n = 55). Pectoral-fin origin located at vertical through median region of opercle. Tip of pectoral fin separated from pelvic-fin origin by four to six scales. Pectoral and pelvic fins of similar size and slightly smaller than anal fin. Pelvic-fin rays i,7 (n = 97, i,
8 in
one specimen
). Pelvic-fin origin situated at midbody and approximately four scales posterior to vertical through dorsalfin origin. Tip of pelvic fin separated from vertical through anal-fin origin by four or five scales. Caudal-fin rays i,15,i (n = 88, 13 branched rays in
one specimen
and 14 branched rays in
six specimens
).
Well developed cycloid scales imbricated along body. Dorsal scales begin in series at posterior margin of parietals and overlap supraoccipital spine. Last vertical series of scales on caudal peduncle forms slightly convex arch on caudal-fin base in lateral view. Anterior margin of scales with small recess and posterior margin rounded. Approximately eight
radii
extending from center of scale to its anterior margin and around eighteen
radii
, some anastomosed, extending from center of scale to its dorsal, posterior, and ventral margins. Lateral line straight and complete, extending from posteroventral margin of supracleithrum to posterior most scale in body. Lateral line with 42-46 (n = 90, 42 in
five specimens
and
46 in
four specimens
; mode: 44, n = 36) perforated scales (
Table 2
). Lateral-line scales with single laterosensory canal. Longitudinal series of scales between lateral line and dorsalfin origin 5.5-6.5 (n = 92; mode: 5.5, n = 86). Longitudinal series of scales between lateral line and pelvic-fin origin 4.5- 5.5 (n = 93; mode: 5.5, n = 75). Longitudinal series of scales around caudal peduncle 20 (n = 92).
Approximately 9 gill rakers on first epibranchial, most in form of small denticulated plates. Lower branch of first branchial arch with five or six more elongate rakers and approximately 10 plate-like rakers (n = 96). Laterosensory canal along ventral surface of dentary with 4-6 pores (n = 97; mode: 5, n = 74) (
Table 3
).
Color in alcohol.
Ground coloration of head and body dark to light brown, darker dorsally and paler ventrally. Ventral region white in several specimens. Approximately seven dark parallel diagonal bars along dorsal region, bars extending anteroventrally to just below lateral line. Diagonal bars in many specimens continuing posteroventrally to approximately two longitudinal scale series below lateral line, resulting in chevron-like pattern. Dorsal portions of bars more evident than ventral region. Bars more conspicuous in specimens with light brown ground coloration. Dorsal surface of head dark brown. Lips with alternating dark and light vertical bands, but completely black in some of largest specimens examined (
ca.
300 mm
SL). Ventral surface of dentaries varying from white in small specimens (
ca.
40 mm
SL), to alternating dark and light transverse stripes in specimens around
130 mm
SL, to completely dark in larger specimens. Coloration of infraorbital region and dorsal surface of head similar. Many specimens with two dark stripes radiating posteriorly from eye along infraorbital 6 and dorsal portion of infraorbital 3. Ground coloration of opercular series dark brown. Opercular membrane usually lighter than opercle.
All fins light brown, lighter than body in specimens smaller than
130 mm
SL, with dark spots on rays and interradial membranes forming pattern of irregular dark stripes. Stripes on anal and caudal fins wider and more regular than those on dorsal fin. Ventral surfaces of pectoral and pelvic fins either lighter than, or with same pattern as, dorsal surface, but with pattern less conspicuous. Fins of largest specimens (
ca
.
300 mm
SL) usually darker than rest of body.
Distribution.
In the rio São Francisco basin and upper reaches of rio
Paraná
basin, including rios Grande, Paranaíba and Piquiri.
Hoplias intermedius
also occurs in tributaries of rio Doce,
Minas Gerais State
(
Fig. 3
).
Remarks.
Syntypes
of
Macrodon intermedius
are deposited in the BMNH collection, and permit its clear placement in the
Hoplias lacerdae
group. Data presented herein matches information from the original description of
M
.
intermedius
.
Oyakawa (1990)
included the nominal species
Erythrinus microcephalus
Agassiz, 1829
and
Macrodon intermedius
Günther,
1864
in the
Hoplias lacerdae
group, with latter being considered a junior synonym of the former (
Oyakawa, 2003
). These names are available for the taxon occurring in the upper rio São Francisco drainage, since
E
.
microcephalus
was described from “rio São Francisco” and
M
.
intermedius
from “rio Cipó”, one of its tributaries. As discussed above, many specimens of species described by Spix and Agassiz (1829) were lost during World War II, as well as the
holotype
of
Erythrinus microcephalus
is also missing (
Terofal, 1983
;
Kottelat, 1988
). Unlike the situation with
Erythrinus brasiliensis
(see above), the original description of
E. microcephalus
, although mentioning that the tongue is edentate, is unclear as to the alignment of the contralateral dentaries noting only that “branches of the lower jaw narrow and convex throughout their length, farther apart when the mouth is closed and distant from the other by a greater space than their transverse diameter” [our translation]. This makes it difficult to determine whether
Hoplias microcephalus
belongs to the
H
.
lacerdae
or to the
H
.
malabaricus
species groups. Neither
Hoplias microcephalus
nor
H
.
intermedius
have been recently used, except for a catalog based on preliminary data (
Oyakawa, 2003
), but previous authors included both epithets as synonyms of
H
.
malabaricus
(
e
.
g
.
Steindachner, 1874
;
Lütken, 2001
). The younger name,
H
.
intermedius
is certainly a member of the
H. lacerdae
group whereas the older one,
H
.
microcephalus
cannot be unambiguously assigned to this group. Since neither these names has been used recently,
H
.
intermedius
is herein chosen to designate this taxon.
In describing
Macrodon intermedius
,
Günther (1864)
cited
two specimens
, but made no reference to either being the
holotype
, and both are thus
syntypes
of the species. Following Article 74 of the International Code of Zoological Nomenclature (
ICZN, 1999
), one of the
syntypes
is designated a
lectotype
(BMNH 1861.5.16.6) (
Fig. 9
), and the other becomes a
paralectotype
(BMHN 1861.5.16.7).
Hoplias intermedius
has an interesting disjunct distribution, occurring in the upper stretches of rio São Francisco, rio Doce and rio
Paraná
. In the latter basin, the species is not known to occur downstream of the Sete Quedas. Similar distributions are reported for other fish species (
Menezes, 1988
; Vari & Harold, 2001).
Dergam
et al
. (2002)
demonstrated that populations of
H
.
malabaricus
from the upper rio Doce, upper rio
Paraná
, and upper rio
Paraíba
do Sul are genetically close, indicating a possible common origin or recent exchanges between these basins.
Vieira
et al
. (2005)
also suggested a common ancestry between the rios São Francisco and Doce based on their ichthyofauna.
Fig. 9.
Hoplias intermedius
(lectotype of
Macrodon intermedius
) BMNH 1861.5.16.6, 533.4 mm SL, rio Cipó, Minas Gerais State, Brazil.
Current knowledge of the geological history of eastern South America indicates that the origin of coastal rivers involved successive erosion of the eastern margin of the platform associated with consequent upland river capture, giving rise to the various independent basins draining into the Atlantic Ocean (
Potter, 1997
;
Ribeiro, 2006
). According to these authors, six major uplift events created megadomes that worked synergistically with marginal erosion and upland stream capture along the Atlantic coast of South America when the latter and Africa were separated during the opening of the Atlantic Ocean. One of these megadomes, the “Mantiqueira-Angola”, is represented in
Brazil
by highlands extending from
São Paulo
and
Rio de Janeiro
states north to
Minas Gerais state
, and was responsible for isolating the upper stretches of the rios São Francisco,
Paraná
and Doce. Therefore, it is possible that the disjunct distribution pattern of
Hoplias intermedius
, as well as of other examples cited above, results from a common history of these basins.
Goeldi (1898)
cited
Macrodon intermedius
in the Ilha de Marajó, in the mouth of rio Amazonas. Under current understanding of the distribution of
H. intermedius
it is clear that these records of the species in the Amazon basin were based on misidentifications. The only species of
H
.
lacerdae
group occurring in the vicinity of Ilha de Marajó is
H
.
curupira
, described in the present study. However, the number of lateral line scales (43) reported by
Goeldi (1898)
does not match with the range registered for
H
.
curupira
(34-39).
Alves & Pompeu (2001), Pompeu &Alves (2003),
Vieira
et al
. (2005)
and
Silva
et al
. (2006a)
stated that
Hoplias
aff.
lacerdae
(=
H
.
intermedius
) was introduced into rio São Francisco because it was originally described from rio Ribeira de Iguape and was missing from earlier ichthyological surveys in the rio São Francisco. The absence of
H
.
intermedius
in previous reports of the São Francisco fish fauna is due to the fact that past naturalists failed to recognize two groups of species in that basin based on the orientation of the contralateral dentaries (
Lütken, 2001
).This resulted in taxonomic confusion and the placement of
H
.
intermedius
in the synonym of
H. malabaricus
. After these two groups had been formally defined by
Oyakawa (1990)
,
Hoplias
aff.
lacerdae
(=
Hoplias intermedius
) began to be included in the ichthyological surveys of the rio São Francisco, but was erroneously regarded as an exotic species introduced from the rio Ribeira de Iguape basin.
Although several karyotypes have been reported for the
Hoplias malabaricus
group (
e
.
g
.
Bertollo
et al
., 1983
; Dergam & Bertollo, 1990;
Bertollo
et al
., 2000
), only one karyotype has been described for specimens of the
Hoplias lacerdae
group collected in the upper rio
Paraná
basin (
Bertollo
et al
., 1978
). The diploid number cited by these authors, 2n = 50, is regarded herein as belonging to
H
.
intermedius
, as that species occurs in the upper rio
Paraná
basin. Further karyotype and molecular studies involving
Hoplias intermedius
from rio São Francisco and rio Doce basins would greatly aid in the knowledge of this species regarding its disjunct distribution.
Hoplias intermedius
inhabits main rivers channels and marginal lagoons (
Vieira
et al
., 2005
). Juveniles were captured in floodplain lakes (
Meschiatti
et al
., 2000
). The species is common in reservoirs (
e
.
g
. Cunico & Agostinho, 2006;
Silva
et al
., 2006a
) and has economic importance (Alves & Pompeu, 2001;
Vieira
et al
., 2005
). Its piscivorous habit (Alvim & Peret, 2004) makes it vulnerable to the bioaccumulation of mercury. In the rio das Velhas, a tributary to the rio São Francisco, its flesh had the highest permitted level of mercury (Alves & Pompeu, 2001).