The genera of the Neotropical armored catfish subfamily Loricariinae (Siluriformes: Loricariidae): a practical key and synopsis.
Author
Raphael Covain
Author
Sonia Fisch-Muller
text
Zootaxa
2007
1462
1
40
http://www.zoobank.org/urn:lsid:zoobank.org:pub:D1F13841-BD7B-4D00-B57D-9CBEC187B83C
journal article
z01462p001
D1F13841-BD7B-4D00-B57D-9CBEC187B83C
[[ Subfamily
Loricariinae
]]
Results
Morphological data used in the analyses are given in Table 1. The Hill & Smith analysis revealed structuring of the data on the two first axes (Fig. 1c) that explained 52% of the total inertia of the scatter. The projection of the individuals onto the two first factorial axes (Fig. 1a) showed a partition of the 30 genera into two groups along the first axis. These two groups corresponded to the two tribes,
Loricariini
and
Harttiini
, the former comprising
Planiloricaria
,
Dentectus
,
Crossoloricaria
,
Apistoloricaria
,
Rhadinoloricaria
,
Pseudohemiodon
,
Pyxiloricaria
,
Spatuloricaria
,
Paraloricaria
,
Ricola
,
Brochiloricaria
,
Reganella
,
Loricaria
,
Dasyloricaria
,
Rineloricaria
,
Pseudoloricaria
,
Limatulichthys
,
Furcodontichthys
,
Loricariichthys
, and
Hemiodontichthys
, and the latter comprising
Harttia
,
Harttiella
,
Lamontichthys
,
Pterosturisoma
,
Sturisomatichthys
,
Aposturisoma
, and
Sturisoma
.
Metaloricaria
and
Ixinandria
appeared intermediate between these two groups. The second axis organized the genera at an infra-tribal level according to their morphological resemblance. For example,
Planiloricaria
,
Dentectus
,
Crossoloricaria
,
Apistoloricaria
,
Rhadinoloricaria
,
Pseudohemiodon
, and
Pyxiloricaria
appeared morphologically more closely related to each other than to
Pseudoloricaria
,
Limatulichthys
,
Furcodontichthys
,
Loricariichthys
, and
Hemiodontichthys
. The projection onto the first factorial plane of the variables (Fig. 1b) defined the primary morphological tendencies of each tribe along the first axis. The
Harttiini
were characterized by numerous and pedunculated teeth, a caudal fin with more branched rays, the absence of postorbital notches and predorsal keels, a rounded mouth, papillose lips weakly or not fringed, and short maxillary barbels. The
Loricariini
were characterized by a more important variation in lips and teeth shape, the frequent presence of postorbital notches and predorsal keels, longer maxillary barbels, and less numerous teeth and branched rays in the caudal fin. The second axis defined morphological groups in each tribe mainly on the basis of dentition and lip structure. Among the
Loricariini
,
Planiloricaria
,
Dentectus
,
Crossoloricaria
,
Apistoloricaria
,
Rhadinoloricaria
,
Pseudohemiodon
, and
Pyxiloricaria
shared filamentous lips, a trapezoidal mouth opening, and teeth often spoon-shaped and smaller.
Pseudoloricaria
,
Limatulichthys
,
Furcodontichthys
,
Loricariichthys
, and
Hemiodontichthys
shared bilobate lips and bicuspid teeth often reduced in size. Among the
Harttiini
,
Metaloricaria
showed a horse-shoe like mouth shape and smaller pedunculated teeth. Other genera were difficult to characterize and another approach was clearly necessary. A cluster analysis (Fig. 2) grouped genera based on their degree of morphological resemblance.
Metaloricaria
and
Farlowella
were the most divergent genera and formed the base of the tree. Two groups were then partitioned that corresponded to the two tribes,
Harttiini
and
Loricariini
. The
Harttiini
was comprised of
Aposturisoma
, the most morphologically divergent, followed by
Lamontichthys
, and then
Ixinandria
. This tribe was then divided into two other groups, one formed by
Harttia
and
Harttiella
, and another by
Sturisoma
joined with
Pterosturisoma
and
Sturisomatichthys
. The
Loricariini
divided into two principal groups. The
Loricariichthys
group was formed by
Furcodontichthys
,
Loricariichthys
,
Hemiodontichthys
,
Pseudoloricaria
, and
Limatulichthys
. The second group was subdivided into three groups: the
Pseudohemiodon
group consisting of
Reganella
,
Pseudohemiodon
,
Pyxiloricaria
,
Planiloricaria
,
Dentectus
,
Rhadinoloricaria
,
Crossoloricaria
, and
Apistoloricaria
; the
Rineloricaria
group formed by
Spatuloricaria
,
Rineloricaria
, and
Dasyloricaria
; and the
Loricaria
group formed by
Loricaria
,
Paraloricaria
,
Ricola
, and
Brochiloricaria
. Our analyses resulted in the placement of two taxa that was inconsistent with previous classifications:
Ixinandria
appeared among
Harttiini
although its dentition and presence of postorbital notches align it with
Loricariini
; and
Spatuloricaria
appeared at the base of the
Rineloricaria
and
Loricaria
groups. Because these genera share similar lip structures, we followed
Isbruecker
(1979) by assigning them to the
Rineloricaria
group of the
Loricariini
.
Metaloricaria
and
Farlowella
, located at the base of the tree because of their particular morphology, were assigned to the tribe
Harttiini
, following
Isbruecker
(1979) and Rapp Py-Daniel (1997). To extract the main characteristics of each genus, shared as well as unique, new Hill & Smith analyses were performed on the above named groups. The projection of the individuals and qualitative variables onto the first factorial plane (Fig. 1c) summarized all this information by connecting the individuals to the center of gravity of the different modalities of the different variables possessed. For example,
Metaloricaria
(species 17) possesses a complete abdominal cover (A3) without particular organization (B2), neither postorbital notches nor predorsal keels (C1, D1), papillose lips (E1), no fringed barbels (F1), a horse-shoe like mouth shape (G2, unique character), teeth pedunculated and reduced in size (H3, unique character), short maxillary barbels (I2), no rostrum (J2), and a pointed snout (K2). Some variables with modalities close to the axes and to the center appear weakly informative on the first plane, such as the presence or absence of secondary organization in the abdominal cover (B) or the presence or absence of a rostrum (J).
FIGURE
1. Hill & Smith analysis (1976) of the subfamily
Loricariinae
. a: projection of 30 individuals representing the 30 genera numbered as in Table 1 onto the first factorial plane of the Hill & Smith analysis (axis 1 horizontal and axis 2 vertical); b: projection of the 17 variables onto the first factorial plane of the Hill & Smith analysis (title and modalities in Table 1); c: projection of the individuals and of the qualitative variables onto the first factorial plane of the Hill & Smith analysis, one plane representing one qualitative variable (title and modalities in Table 1); d: eigenvalues.
TABLE
1. Main morphological data recorded on the selected specimen for each genus of the subfamily
Loricariinae
. A star (*) indicates data taken from the literature. I to VI: Quantitative data. I: number of caudal-fin rays (including spines); II: number of pectoral-fin rays (including spine); III: number of pelvic-fin rays (including spine); IV: number of dorsalfin rays (including spine); V number of premaxillary teeth; VI: number of dentary teeth. A to K: qualitative data. A: abdominal cover with three modalities: 1 = absent, 2 = present incomplete, 3 = present complete; B: secondary organization in the abdominal cover with two modalities: 1 = absent, 2 = present; C: postorbital notches with three modalities: 1 = absent, 2 = present weak, 3 = present deep; D: predorsal keels with two modalities: 1 = absent, 2 = present; E: lips structure with three modalities: 1 = papillose, 2 = filamentous, 3 = rather smooth; F: fringed barbels with two modalities: 1 = absent, 2 = present; G: mouth shape with four modalities: 1 = elliptical, 2 = horse shoe like, 3 = bilobate, 4 = bilobate with trapezoidal opening; H: tooth shape with five modalities: 1 = pedunculated, 2 = straight bicuspid, 3 = pedunculated size reduced, 4 = straight bicuspid size reduced, 5 = spoon shaped size reduced; I: maxillary barbels with two modalities: 1 = conspicuous, 2 = inconspicuous; J: rostrum with two modalities: 1 = absent, 2 = present; K: snout shape with two modalities: 1 = rounded, 2 = pointed.
| Genus |
Species |
I |
II |
III |
IV |
V |
VI |
A |
B |
C |
D |
E |
F |
G |
H |
I |
J |
K |
|
Apistoloricaria
|
A. condei
* [1]
|
12 |
7 |
6 |
7 |
4 |
7 |
2 |
2 |
2 |
2 |
2 |
2 |
4 |
5 |
1 |
1 |
2 |
|
Aposturisoma
|
A. myriodon
[2]
|
13 |
7 |
6 |
6 |
85 |
85 |
3 |
2 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
2 |
|
Brochiloricaria
|
B. macrodon
[3]
|
12 |
7 |
6 |
7 |
5 |
6 |
3 |
1 |
2 |
2 |
2 |
2 |
3 |
2 |
1 |
1 |
2 |
|
Crossoloricaria
|
C. rhami
[4]
|
12 |
7 |
6 |
7 |
3 |
4 |
2 |
2 |
2 |
2 |
2 |
2 |
4 |
5 |
1 |
1 |
2 |
|
Dasyloricaria
|
D. cf. filamentosa
[5]
|
12 |
7 |
6 |
7 |
13 |
13 |
3 |
2 |
3 |
2 |
1 |
2 |
3 |
2 |
1 |
1 |
2 |
|
Dentectus
|
D. barbarmatus
* [6]
|
12 |
7 |
6 |
7 |
3 |
3 |
3 |
1 |
2 |
2 |
2 |
2 |
4 |
5 |
1 |
1 |
1 |
|
Farlowella
|
F. platoryncha
[7]
|
13 |
7 |
5 |
6 |
23 |
17 |
3 |
2 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
2 |
|
Furcodontichthys
|
F. novaesi
* [8]
|
12 |
7 |
6 |
7 |
10 |
6 |
3 |
2 |
3 |
2 |
3 |
1 |
3 |
2 |
1 |
2 |
2 |
|
Harttia
|
H. guianensis
[9]
|
14 |
7 |
6 |
7 |
85 |
68 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
1 |
1 |
|
Harttiella
|
H. crassicauda
[10]
|
14 |
7 |
6 |
7 |
33 |
31 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
1 |
1 |
|
Hemiodontichthys
|
H. acipenserinus
[11]
|
12 |
7 |
6 |
7 |
0 |
8 |
3 |
2 |
3 |
2 |
3 |
1 |
3 |
4 |
2 |
2 |
2 |
|
Ixinandria
|
I. montebelloi
[12]
|
12 |
7 |
6 |
7 |
10 |
8 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
2 |
2 |
1 |
1 |
|
Lamontichthys
|
L. filamentosus
[13]
|
14 |
8 |
6 |
7 |
38 |
36 |
3 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
1 |
1 |
|
Limatulichthys
|
L. griseus
[14]
|
12 |
7 |
6 |
7 |
7 |
10 |
3 |
1 |
2 |
1 |
3 |
1 |
3 |
4 |
2 |
1 |
2 |
|
Loricaria
|
L. sp.
[15]
|
12 |
7 |
6 |
7 |
3 |
6 |
3 |
1 |
3 |
2 |
2 |
2 |
3 |
2 |
1 |
1 |
2 |
|
Loricariichthys
|
L. platymetopon
[16]
|
12 |
7 |
6 |
7 |
8 |
15 |
3 |
2 |
3 |
1 |
3 |
1 |
3 |
4 |
2 |
1 |
2 |
|
Metaloricaria
|
M. paucidens
[17]
|
13 |
7 |
6 |
7 |
11 |
13 |
3 |
1 |
1 |
1 |
1 |
1 |
2 |
3 |
2 |
1 |
2 |
|
Paraloricaria
|
P. agastor
[18]
|
12 |
7 |
6 |
7 |
4 |
7 |
2 |
1 |
2 |
2 |
2 |
2 |
3 |
2 |
1 |
1 |
2 |
|
Planiloricaria
|
P. cryptodon
[19]
|
12 |
7 |
6 |
7 |
0 |
3 |
2 |
1 |
2 |
2 |
2 |
2 |
4 |
5 |
1 |
1 |
1 |
|
Pseudohemiodon
|
P. laticeps
[20]
|
12 |
7 |
6 |
7 |
5 |
7 |
3 |
1 |
2 |
2 |
2 |
2 |
4 |
5 |
1 |
2 |
2 |
|
Pseudoloricaria
|
P. laeviuscula
[21]
|
12 |
7 |
6 |
7 |
10 |
12 |
3 |
1 |
2 |
1 |
3 |
1 |
3 |
2 |
2 |
1 |
2 |
|
Pterosturisoma
|
P. microps
[22]
|
14 |
7 |
6 |
7 |
46* |
46* |
3 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
1 |
1 |
|
Pyxiloricaria
|
P. menezesi
* [23]
|
12 |
7 |
6 |
7 |
3 |
3 |
3 |
1 |
2 |
2 |
2 |
2 |
4 |
5 |
2 |
1 |
2 |
|
Reganella
|
R. depressa
[24]
|
12 |
7 |
6 |
7 |
0 |
15 |
3 |
1 |
2 |
1 |
3 |
2 |
4 |
5 |
2 |
2 |
2 |
|
Rhadinoloricaria
|
R. macromystax
[25]
|
12 |
7 |
6 |
7 |
4 |
8 |
2 |
2 |
2 |
2 |
2 |
2 |
4 |
5 |
1 |
2 |
2 |
|
Ricola
|
R. macrops
[26]
|
12 |
7 |
6 |
7 |
10 |
10 |
3 |
1 |
2 |
2 |
2 |
2 |
3 |
2 |
1 |
1 |
2 |
|
Rineloricaria
|
R. steindachneri
[27]
|
12 |
7 |
6 |
7 |
7 |
9 |
3 |
1 |
3 |
2 |
1 |
2 |
3 |
2 |
2 |
1 |
2 |
|
Spatuloricaria
|
S. sp.
[28]
|
12 |
7 |
6 |
7 |
3 |
4 |
2 |
1 |
2 |
2 |
1 |
2 |
1 |
2 |
2 |
1 |
2 |
|
Sturisoma
|
S. robustum
[29]
|
14 |
7 |
6 |
7 |
45 |
38 |
3 |
2 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
2 |
|
Sturisomatichthys
|
S. citurensis
[30]
|
14 |
7 |
6 |
7 |
56 |
46 |
3 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
1 |
2 |
FIGURE
2. Cluster analysis of the subfamily
Loricariinae
. Dendrogram based on morphological distances matrix using UPGMA. A:
Harttiini
tribe; B:
Loricariini
tribe. Colors represent the different ranks established::
Harttiini
tribe;:
Loricariini
tribe;:
Loricariichthys
group;:
Rineloricaria
group;:
Loricaria
group;:
Pseudohemiodon
group. Braces indicate the genera confirmed inside their own group.
Key
to the genera
The methodology used in this study enabled us to sort the valuable information (grouping of individuals according to combinations of variables) into a hierarchy and create morphologically coherent groups by summarizing the characteristics of each genus. These results are intended to rectify problems with the identification of taxa and should not be interpreted as a phylogeny. We do not use the subtribal rank defined by
Isbruecker
(1979, 1981a) because the divisions are not well-defined. The results of our analyses support the recognition of two tribes,
Harttiini
and
Loricariini
, the latter of which contains four morphological groups. Characters that are underlined in the key couplets are also illustrated on the same page and identified by letters between brackets [a, b, c... aq, ar]. These letters are presented in alphabetical order in the couplets and in the illustrations, with two exceptions: character [ab] (first proposed in lead 13a, is illustrated in Figure 20b), and character [af] (first proposed in lead 15b, is illustrated in Figure 23a). Arrows indicate the most important characters for identification purposes. The numbers of the figures correspond to the numbers of the key couplet. Additional features are given at the level of identification to confirm this identification, certain specimens being sometimes poorly preserved or poorly characterized like juveniles, and certain genera being relatively variable.
1
a. - Caudal fin [a] with i-12-i or i-11-i rays; teeth pedunculated [b], bicuspid, numerous (>10 per premaxillae), organized in comb and weakly differentiated; sometimes with filamentous extensions [c] on pectoral [d], dorsal [e], upper [f] and/or lower caudal [g] spines:
Harttiini
.................................................................2
1b. - Caudal fin [a] with i-10-i rays; teeth straight [h] bicuspid, spoon-shaped [i], not numerous (<20 per premaxillae), strongly differentiated, sometimes reduced in size or absent; often with a more or less strong whip [j] on upper caudal spine [f]:
Loricariini
..............................................................................................................10
2
a. - Mouth shape elliptical [k]...........................................................................3
2b. - Mouth shape horseshoe like [1]; with three buccal papillae [m], lateral ones trilobate; teeth small and not numerous (~ 10 per premaxillae):........
Metaloricaria
3a. - Caudal peduncle [n] strongly depressed, elliptical in transverse section (in average, the minimal depth of the caudal peduncle represents 1 to 3 % of the SL) .................................................................................................................................4
3b. - Caudal peduncle [n] weakly depressed, more or less circular in transverse section (in average, the minimal depth of the caudal peduncle represents 5 % of the SL); abdomen naked; body covered by numerous, short and dense odontodes giving a velvety aspect; species of small size (~ 50 mm):....................................
Harttiella
4
a. - Rostrum [o] present........................................................................................5
4b. - Rostrum [o] absent.........................................................................................7
5a. - Dorsal fin [p] originating more or less in front of the anal-fin [q] origin......6
5b. - Dorsal fin [p] originating more or less in front of the pelvic-fin [r] origin; abdominal cover complete and weakly structured in two to three rows: ........
Sturisoma
6
a. - Teeth not numerous (~ 20 per premaxillae); two to three rows of abdominal plates; general aspect slender, reminiscent of a stick:..............................
Farlowella
6b. - Teeth numerous (~ 100 per premaxillae); three rows of abdominal plates: ..............................................................................................................
Aposturisoma
7a. - Snout rounded.................................................................................................8
7b. - Snout pointed; abdominal cover complete without particular organization, or weakly structured in two to three rows.........................................
Sturisomatichthys
8
a. - Pectoral fins [s] with i-6 rays.........................................................................9
8b. - Pectoral fins [s] with i-7 rays; pectoral spine [d] sometimes with filamentous extensions [c]:....................................................................................
Lamontichthys
9a. - Eye diameter large (on average ~ 20% of head length); tip of snout naked; without filamentous extensions [c] on pectoral [d], upper [f] and lower caudal [g] spines:............................................................................................................
Harttia
9b. - Eye diameter small (on average ~ 10% of head length); tip of snout covered by plates; with filamentous extensions [c] on pectoral [d], upper [f] and lower caudal [g] spines:...............................................................................
Pterosturisoma
10
a. - Lower lip bilobate [t] with a median furrow [u]; surface of this lip more or less smooth or weakly papillose; presence of a double abdominal keel [v]; throat never covered; whip [j] on upper caudal spine [f] weak or absent:
Loricariichthys
group...........................................................................................11
10b. - Absence of such a combination of characters; lower lip more often strongly papillose [w] or filamentous [x]..............................................................................15
11a. - Presence of a secondary structure in the organization of the abdominal cover forming a perfect elliptical area [y] at the level of the pectoral girdle: ...........................................................................................................
Loricariichthys
11b. - Without such structure................................................................................12
12
a. -With conspicuous lines of odontodes [z] on head and snout......................13
12b. - Without lines of odontodes [z] on head and snout......................................14
13a. - Rostrum [o] strongly pronounced; maxillary barbels [aa] short; premaxillary teeth [ab] absent; abdomen covered by large rectangular plates organized in three rows:.............................................................................................
Hemiodontichthys
13b. - Rostrum [o] weakly pronounced; maxillary [aa] and fringed [ac] barbels conspicuous and gathered in series at the lip corners; premaxillary teeth [ab] present; abdomen covered by large plates organized in two rows:...............
Furcodontichthys
14
a. - Abdomen covered by small plates without particular organization; in adults pelvic-fin spine [ad] longer than last pelvic-fin [r] ray; in juveniles presence of a conspicuous basicaudal spot [ae]:....................................................
Pseudoloricaria
14b. - Abdomen covered by medium-sized plates weakly structured in two to three rows; in adults last pelvic-fin [r] ray longer than pelvic-fin spine [ad]; in juveniles absence of a conspicuous basicaudal spot [ae]:.................................
Limatulichthys
15a. - Lips papillose [w]; fringed barbels [ac] of lower lip absent or inconspicuous:
Rineloricaria
group..............................................................................................16
15b. - Lips generally filamentous [x] or smooth [af]; fringed barbels [ac] of lower lip generally conspicuous......................................................................................19
16
a. - Abdomen partially to completely covered by plates..................................17
16b. - Abdomen naked; snout rounded; mouth circular; postorbital notches [ag] deep; strongly depressed body covered by numerous, short, and dense odontodes giving a velvety aspect; species of small size (~ 90 mm):........................
Ixinandria
17a. - Abdomen partially to completely covered by medium-sized plates; mouth not circular; postorbital notches [ag] deep.............................................................18
17b. - Abdomen covered by very small plates not contiguous; mouth circular and thick; postorbital notches [ag] weak; teeth few (~ 4 per premaxillae); body depth strong (~ 12% of SL); presence of a long whip [j] on upper caudal spine [f]; predorsal keels [ah] strong;...........................................................................
Spatuloricaria
18
a. - Without a secondary structure in abdominal cover; abdominal cover weakly organized in rows; predorsal keels [ah] more or less pronounced; species of medium size (generally <20 cm):......................................................................
Rineloricaria
18b. - With a secondary structure on abdominal cover consisting in double median row of plates organized in chevrons [ai]; predorsal keels [ah] strong; species of large size (generally> 25 cm):.....................................................................
Dasyloricaria
19a. - Mouth opening without particular shape; the most often predorsal keels [ah] strong; body generally weakly depressed:
Loricaria
group.................................20
19b. - Mouth opening trapezoidal [aj]; predorsal keels [ah] weak; body strongly depressed:
Pseudohemiodon
group......................................................................23
20
a
. - Abdominal cover the most often complete made of medium to small plates ...............................................................................................................................21
20b. - Abdominal cover incomplete, made of very small plates not contiguous; equal size [ak] of dentary [al] and premaxillary teeth [ab]; tooth size-reduced; maxillary barbels [aa] long, branched and reaching pectoral-fin [s] origin: ..............................................................................................................
Paraloricaria
21
a. - Equal size [ak] of dentary [al] and premaxillary teeth [ab]; tooth very long: ...........................................................................................................
Brochiloricaria
21b. - Different size [am] of dentary [al] and premaxillary teeth [ab], the latter almost two times longer than the former...............................................................22
22a. - 10 to 15 premaxillary teeth [ab]; lips extremely filamentous [x]; maxillary barbels [aa] long, strongly branched, and reaching pectoral-fin [s] origin: .........................................................................................................................
Ricola
22b. - 3 to 5 premaxillary teeth [ab]; lips filamentous [x]; maxillary barbels [aa] not reaching pectoral-fin [s] origin:..........................................................
Loricaria
23
a. - Rostrum [o] weakly pronounced or absent:................................................24
23b. - Rostrum [o] strongly pronounced; premaxillary teeth [ab] absent; dentary teeth [al] numerous (~15 per dentary) and reduced in size; lips smooth [afj; maxillary barbels [aa] short; abdominal cover complete, made of little plates without particular organization; throat covered:........................................
Reganella
24a. - Abdominal cover complete:........................................................................25
24b. - Abdominal cover incomplete, most often consisting in a double median row [an] of plates:.........................................................................................................27
25
a. - Maxillary barbels [aa] inconspicuous, not reaching gill opening [ao]; teeth very difficult to observe, invisible in normally preserved specimens....................26
25b. - Maxillary barbels [aa] conspicuous, reaching gill opening [ao]; teeth visible; head large; body strongly depressed:.............................................
Pseudohemiodon
26a. - Head triangular and little; body large; trapezoidal in transverse section; with a fleshy flap [ap] partially covering the branchiostegal membrane [aq]: ...............................................................................................................
Pyxiloricaria
26b. - Head rounded; upper lip with numerous filaments reaching the lower lip margin; with plates on the external margin of the maxillary barbels [aa]: ....................................................................................................................
Dentectus
27
a. - Premaxillary teeth [ab] present...................................................................28
27b. - Premaxillary teeth [ab] absent; head rounded; eyes small; maxillary barbels [ac] conspicuous, reaching beyond pectoral-fin [s] origin:....................
Planiloricaria
28a. - maxillary barbels [aa] conspicuous, reaching beyond pectoral-fin [s] origin; lips stongly filamentous [x]...................................................................................29
28b. - maxillary barbels [aa] reaching gill opening [ao]; lips fairly filamentous [x] ..........................................................................................................
Crossoloricaria
29
a. - Rostrum [o] pointed; 12 fringed barbels [ac]; iris operculum [ar] generally present:...........................................................................................
Rhadinoloricaria
29b. - Rostrum [o] generally rounded; 14 fringed barbels [ac]; iris operculum [ar] absent or vestigial:.............................................................................
Apistoloricaria