Taxonomic revision of Spectracanthicus Nijssen & Isbrücker (Loricariidae: Hypostominae: Ancistrini), with description of three new species
Author
Chamon, Carine C.
Author
Rapp Py-Daniel, Lúcia H.
text
Neotropical Ichthyology
2014
12
1
1
25
journal article
6619
10.1590/S1679-62252014000100001
10c0936c-f405-4c8d-b34b-9c825f2683a5
1982-0224
4774086
Spectracanthicus immaculatus
,
new species
Figs. 9-10
Holotype
.
MZUSP 92797
,
63.8 mm
SL,
Brazil
,
Pará
,
rio Tapajós
, near
Itaituba
, approximately
4°16’46.56”S
55°59’5.77”W
,
7 Nov 2006
,
L. M. Sousa
&
J. L. Birindelli.
Paratypes
.
MZUSP 92617
,
11
,
38.2-82.2 mm
SL (1 c&s,
81.2 mm
SL),
Brazil
,
Pará
,
rio Tapajós
near
Itaituba
and
Pimental
, approximately
4°16’46.56”S
55°59’5.77”W
,
8 Nov 2006
,
L.M. Sousa
&
J. L. Birindelli
.
Diagnosis.
Spectracanthicus immaculatus
can be distinguished from all congeners by its color pattern consisting of a dark gray body, without dots or spots, and by having very slender teeth (
vs.
with small to mid-sized yellowish dots in
S. punctatissimus
,
S. murinus
, and
S. tocantinensis
; and large white spots in
S. zuanoni
). It further differs from
Spectracanthicus punctatissimus
and
S. zuanoni
by the pointed snout in dorsal view (
vs
. snout rounded). Other characters that differs the new species from other congeners are: nasal quadrangular (
vs
. nasal L-shaped); posterior margin of pterotic-supracleithrum without contact with posterior margin of orbit (
vs.
with large contact with orbit in
S. murinus
and small contact in remaining species); cartilage area of basipterygia short (
vs.
elongate in remaining species, except in
S. murinus
); anterior fenestrae of cartilage area of basipterygia large in size (
vs.
small to median size in remaining species, except in
S. tocantinensis
) (
Fig. 11
).
Description.
Morphometric and meristic data summarized in
Table 3
. Dorsal profile of body slightly convex from tip of snout to vertical through of dorsal fin; concave, nearly straight from that point to caudal-fin origin.Ventral profile straight from snout tip to origin of caudal fin.Ventral surface from tip of snout to urogenital papillae lacking plates, except for few small plates at pectoral and pelvic-fins origins. Body deep and robust even at caudal peduncle. Head and trunk lacking keels or ridges. Greatest body depth at dorsal-fin origin; lowest at caudal peduncle.
Fig. 9.
Spectracanthicus immaculatus
, holotype, MZUSP 92797, 64.6 mm SL, rio Tapajós, Pará State, Brazil.
Fig. 10.
Color in live of
Spectracanthicus immaculatus
, paratype, MZUSP 92617, 81.2 mm SL. Image by L. Sousa.
Fig. 11.
Basipterygia and pelvic fin of (a)
Spectracanthicus murinus
, MZUSP
24293, 37.0 mm SL; (b)
S. immaculatus
, paratype, MZUSP 92617; 58.9 mm SL and (c)
S
.
tocantinensis
, paratype, MZUSP 34265, 65.4 mm SL. Scale bars = 2 mm. Image by E. Baena.
Table 3.
Morphometric and meristic data of
Spectracanthicus immaculatus
. Values are given as percents of standard length or head length. SD = standard deviation.
Holotype MZUSP 92797 |
n |
Min |
Max |
Mean |
SD |
Standard length |
64.6 |
11 |
38.2 |
82.2 |
69.0 |
- |
Percents of Standard Length |
Head length |
23.5 |
11 |
34.1 |
36.2 |
35.4 |
0.7 |
Head depth |
11.5 |
11 |
16.6 |
29.4 |
20.4 |
3.1 |
Head width |
20.0 |
11 |
18.6 |
33.8 |
31.0 |
4.1 |
Body depth |
11.2 |
11 |
16.6 |
23.1 |
20.1 |
1.9 |
Body width at dorsal |
18.4 |
11 |
24.9 |
31.4 |
28.3 |
2.1 |
Body width at anal |
8.7 |
11 |
12.5 |
16.8 |
14.0 |
1.2 |
Predorsal length |
27.1 |
11 |
39.8 |
44.3 |
42.1 |
1.0 |
Postdorsal length |
14.9 |
11 |
20.2 |
36.0 |
25.7 |
3.8 |
Postanal length |
21.0 |
11 |
24.4 |
32.8 |
28.2 |
2.0 |
Dorsal-spine length |
22.5 |
11 |
23.0 |
31.8 |
28.5 |
2.6 |
Pectoral-spine length |
21.0 |
11 |
27.8 |
35.1 |
29.3 |
1.9 |
Pelvic-spine length |
19.8 |
11 |
24.4 |
27.8 |
26.1 |
0.9 |
Dorsal-base length |
20.3 |
11 |
27.5 |
34.1 |
31.3 |
2.3 |
Caudal peduncle depth |
10.2 |
11 |
12.7 |
14.3 |
13.5 |
0.5 |
Percents of Head Length |
Snout length |
14.4 |
11 |
55.2 |
63.7 |
60.0 |
2.8 |
Interorbital width |
7.5 |
11 |
30.0 |
38.2 |
33.4 |
2.1 |
Orbital diameter |
3.8 |
11 |
13.6 |
16.2 |
14.7 |
0.6 |
Dentary length |
2.2 |
11 |
8.1 |
12.8 |
10.9 |
1.5 |
Counts |
Mode |
Premaxillary teeth |
5 |
11 |
6 |
22 |
12 |
- |
Dentary teeth |
7 |
11 |
8 |
30 |
18 |
- |
Dorsal-fin rays |
i+7 |
11 |
i+7 |
i+7 |
i+7 |
- |
Pectoral-fin rays |
i+6 |
11 |
i+6 |
i+6 |
i+6 |
- |
Pelvic-fin rays |
i+5 |
11 |
i+5 |
i+5 |
i+5 |
- |
Anal-fin rays |
i+4 |
11 |
i+4 |
i+4 |
i+4 |
- |
Caudal-fin rays |
ii+14 |
11 |
ii+14 |
ii+14 |
ii+14 |
- |
Lateral line plates |
23 |
11 |
21 |
23 |
21 |
- |
Caudal peduncle plates |
8 |
11 |
7 |
8 |
7 |
- |
Head wide, convex dorsally; snout and cheeks completely covered by numerous small plates, except for small naked area on tip of snout. Snout slightly rounded in dorsal profile. Nasal elongated, L-shaped. Frontal short with a slight contact with nares anteriorly and orbit posteriorly. Anterior margin of frontal short, reaching posterior margin or half of length of nare. Parieto-supraoccipital short with posterior edge narrow, lacking crest. Sphenotic short, without contact with IO6, lacking conspicuous odontodes. Orbit moderate in size (13.6-16.2% HL), placed dorsolaterally in head. Iris with small dorsal flap over pupil. Pterotic-supracleithrum short with few fenestrae; anterior process forming most posterior margin of orbit. Posterior area of pterotic-supracleithrum with one plate.
Mouth moderate in size, nearly as long as wide. Lips large, covered with papillae; size of papillae decreasing towards posterior margin of lower lip; central buccal papilla absent. Upper lip folded over itself. Maxillary barbel short; base of barbel united to lips with free tip. Lower lip not reaching anterior margin of coracoid. Medial end of premaxillary teeth series almost straight. Premaxillae and dentaries narrow and elongate. Dentaries strongly curved inwards. Teeth medium in size, well developed, slender, with long crown and large lateral cusp. Distal edge of teeth slightly curved inward. Eversible cheek plates with associated hypertrophied odontodes and disposed as unique block connected to opercle, that can be everted to approximately 90
o
from head by opercle movements (
Fig. 12
).
Body covered by five longitudinal series of plates supporting odontodes. Keels absent. Three to four predorsal plates; some small azygous predorsal plates sometimes present. Eight neural bifid spines supporting dorsal fin. Dorsal-fin rays i,7, located posterior to neural spines of vertebral centra 7-17. Dorsal-fin base very long, its length equivalent to 12 dorsal plates, reaching pre-adipose plate and connected to adipose fin by thick membrane. Dorsal-fin spinelet V-shaped with locking mechanism. Pectoral and pelvic fins well developed, medial portion much expanded relative to base; distal margins rounded. Pectoral-fin rays I,6; unbranched ray covered with conspicuous odontodes. Tip of adpressed pectoral fin almost reaching vertical through medial, unbranched, pelvic-fin ray. Pelvic-fin rays i,5; pelvic-fin spine reaching vertical through anal-fin base when adpressed. Anal-fin rays i,4 located posterior to hemal spines of vertebral centra 14-17. Caudal-fin rays i,14,i, truncated; supracaudal plates. Five to six procurrent caudal-fin rays. Caudal peduncle strongly deep in lateral view. Total vertebrae 26, precaudal 8-12. Sixth rib strongly thickened, remaining ribs slender. Infraorbital with 7-8 pores. Infraorbital 4 with little contact with orbit by posterior margin. Infraorbital 6 forming only postero-vental part of orbit. Lateral line pores restrict to hypural plate.
Color in alchool.
Ground color evenly dark gray to dark brown without dots or spots. Ventral surface ochre to light brown without dots. Dorsal surface of body of live specimens gray.
Distribution.
Spectracanthicus immaculatus
is known from rio Tapajós basin, near Itaituba and Pimental,
Pará State
,
Brazil
.
Etymology.
The specific epithet “
immaculatus
” derives from Latin, meaning unspotted or unstained, in allusion to the coloration pattern of the species, lacking dots or spots. An adjective.
Fig. 12.
Suspensorium of
Spectracanthicus immaculatus
, (a) external view and (b) internal view, paratype, MZUSP 92617, 58.9 mm SL. Scale bars = 2 mm. Image by E. Baena.
Fishery and economical importance.
Spectracanthicus immaculatus
is an important resource of ornamental fish. It is also recognized by local fishermen and aquarists as “naná” or “L363” (L-number; Schraml & Schafer, 2004;
Werner
et al
. 2005
). Like
S. murinus
, it is also captured by diving with help of a compressor, a typical way of capturing ornamental fishes in Itaituba and Santarém regions (Sousa & Birindelli, 2009).