Australoheros kaaygua Casciotta, Almiron & Gomez 2006
Creators: name: An, Old Ř Ich Ř Í Č
name: Kullander, Sven O.
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Cichlidae
Australoheros
Australoheros kaaygua

description: Australoheros kaaygua Casciotta, Almirón & Gómez, 2006
(Fig. 13)
Australoheros kaaygua Casciotta, Almirón & Gómez, 2006: 78, fig. 1 (Type locality: arroyo Ñandú, Río Iguazú basin, Misiones, Argentina. Holotype: MACN-ict 8917).
Australoheros sp. “Jacutinga” (Ř íċan & Kullander, 2006).
charrua guarani E0 scales 25.3±0.5 24.0±0.0 caudal vertebrae 13.9±0.4 13.0±0.0 Obrit diameter in head length 36.8±1.5 32.2±2.3 Anal fin spines 7.1±0.3 6.2±0.4 Snout length in head length 26.3±2.0 30.2±2.4 Ceratobranchial 1 gill rakers 6.1±0.6 7.0±0.0 Interorbital width in head length 35.3±2.6 38.7±1.9 charrua minuano caudal vertebrae 13.9±0.4 13.0±0.0 Head length 32.4±1.0 35.9± 1.1 E 0 scales 25.3±0.5 24.1±0.4 Preorbital distance in head length 22.6±3.2 16.7±2.4 Anal fin spines 7.1±0.3 6.3±0.5
Anal fin rays 7.6±0.5 8.4±0.5
L1 scales 17.4±0.7 16.3±0.5 Head width in head length 54.6±1.8 52.4±1.3 Snout length in head length 26.3±2.0 29.6±2.7 Pectoral fin rays 12.9±0.4 12.1±0.4 Obrit diameter in head length 36.8±1.5 35.0±1.6 Material examined. 40 specimens, 24.6–77.0 mm SL. Brazil, Paraná: Rio Iguaçu drainage: NUP 3913, 2, field numbers 3683 and 3967, Rio São Pedro, tributary to Rio Iguaçu, Pinhão county, Paraná State (26ºS/ 51º45'W), 28.iii.1993, collectors: NUPELIA staff; NUP 3914, 1, field number 7743, Rio Iratim (Linígrafo), tributary to Rio Iguaçu, Palmas county, boundary with Pìnhão-PR, Paraná State (26º05´S / 51º45´W), 27.iv.1993, collectors: Nupélia staff; NUP 3915, 1, field number 8861, Rio São Pedro, tributary to rio Iguaçu, Pinhão county, Paraná State (26ºS/ 51º45'W), 28.iii.1993, collectors: Nupélia staff. Brazil, Santa Catarina: MCP 13937, 1, 73.2 mm SL, Rio Jacutinga, Rio Uruguai drainage, road BR 283 from Ceará to Concordia. October 1988. L. Bergmann, E. Pereira, P. Azevedo, and A. Ramírez; MCP 13383, 6, 24.6–77.0 mm SL, Rio Jacutinga, Rio Uruguai drainage, road BR 283 from Ceará to Concordia. 16 February 1989. R. E. Reis, L. Bergmann, E. Pereira, and P. Azevedo; MCP 12509, 1, 75.0 mm SL, Rio Jacutinga, Rio Uruguai drainage, road BR 283 from Ceará to Concordia. October 1988. E. Pereira, L. Bergmann, P. Azevedo, and A. Ramírez; MCP 13011, 6, 44.2–61.4 mm SL, Rio Jacutinga, Rio Uruguai drainage, road BR 283 from Ceará to Concordia. 8 December 1988. R. E. Reis, L. Bergmann, E. Pereira, and P. Azevedo. Brazil, Rio Grande do Sul: MCP 6262, 13/35: A, B, E, F, G, H, I, J, K, L, M, O, S. Sanga das Aguas Frias, Rio Uruguai drainage, Irai. 1985. L. R. Malabarba, R. E. Reis, and S. B. Malman; MCP 12710, J-K, 2, Arroyo Canoin, Rio Uruguai drainage, road from Pirapo to São Nicolau. 2 November 1988. C. Lucena, L. Bergmann, E. Pereira, and P. Azevedo. Argentina, Misiones: ZSM 23482, 1/16: P, 63.1 mm SL, Río Soberbio, Río Uruguay drainage, Soberbio. 1966. J. Foerster; ZSM 23060, 6/12, A (C&S), B (C&S), E, H, K, F, 50.3–66.2 mm SL, Rio Soberbio, Río Uruguay drainage, Soberbio. 1966. J. Foerster. Fractions denote numbers of specimens in mixed lots including more than one species.
Description of Australoheros kaaygua material from Brazil. Based on specimens over 60 mm SL with notes on smaller specimens. Meristic data are summarized in Table 1. Morphometric data are summarized in Table 2.
The description of A. kaaygua from Misiones, Río Iguazú drainage, Argentina, by Casciotta et al. (2006) agrees well with our material from Brazil. Specimens from the Iguaçu drainage of Brazil have only an even shorter caudal peduncle (-1 or fewer vertebrae; the shortest caudal peduncle found in Australoheros) and slightly larger scales, visible as only 3 scales anteriorly between the upper lateral line and origin of D fin, only 1 and 1 small posteriorly. We treat these two differences as intraspecific variation and do not believe that they would credit a separate species status. The analysis by Ř íčan and Kullander (2006) also supports the conspecifity of the Río Iguazú and Río Uruguay specimens.
Shape. See Fig. 13 for general aspect. Comparatively deep bodied (mean body depth 49.6% SL). Snout short, strait in lateral view. Jaws isognathous. Mouth small. In other respects it fits the description of A. scitulus (Ř íčan & Kullander, 2003).
Scales on head and chest not distinctly smaller than on flanks. Scales in E0 row 23(3), 24(16), 25(4). Upper lateral line scales 16(1), 17(6), 18(8). Lower lateral line scales 7(4), 8(7), 9(4). Scales between upper lateral line and dorsal fin 4 anteriorly, 1 big plus 1 small posteriorly. Cheek scale rows 3(14), 4(2). About 8 scale rows between the opercular flap and the anterior insertion of the pelvic fin (as in A. scitulus and A. charrua).
Dorsal fin with one basal scale row, starting from the seventh or eighth spine and running posteriad; interradial scales appear from 14th or 15th spine membrane, in single rows. Anal fin with one basal scale row; interradial scales in single rows, from penultimate spine. Caudal fin densely scaled, scales ctenoid; interradial scales in single rows; hind margin of scaly area concave, extending to between one-third and middle of caudal fin.
Soft dorsal fin pointed, extending beyond middle of caudal fin. D. XVI,9 (16), XVI,10 (13), XVII,8 (2). Soft anal fin pointed, of about the same length as dorsal fin. A. VI,7 (2), VI,8 (3), VII,7 (17), VII,8 (8), VIII,6 (1). Anal fin pterygiophores 11(2), 12(22), 13(7). First pelvic fin ray longest, extending up to the second anal fin spine. Pectoral fin with a rounded tip, third and fourth rays longest, extending just to the midlateral blotch.
P. 12(11), 13(5). Caudal fin rounded to subtruncate.
All teeth caniniform, slightly curved. Outer row teeth increasing in size symphysiad, upper jaw anterior teeth longest, lower jaw anterior teeth subequal. Number of lower jaw teeth up to 16 in one outer hemiseries, upper jaw tooth row much shorter, with about 7 or 8 teeth in one outer hemiseries.
Lower pharyngeal tooth plate not studied.
Gill rakers externally on first gill arch, 2 epibranchial, 1 in angle, 5(4), 6(11), 7(1) ceratobranchial.
Vertebrae 13+13=26(29), 13+14=27(2). Caudal peduncle containing -1(4), -0.5(1), 0(5), 0.5(4), 1(14), 1.5(1) vertebrae.
Color pattern in alcohol. Six vertical flank bars, a caudal peduncle bar confluent with the caudal bar base bar, and a midlateral stripe bearing the midlateral blotch in the third flank bar make up the principal markings. All fins and body are without conspicuous dark spots or blotches. The midlateral stripe is more distinct anteriorly from the midlateral blotch posteriorly, and the midlateral blotch itself is a dominant coloration element. Vertical bars are relatively wide, faint, indistinct in their ventral parts. The midlateral stripe posteriorly from the midlateral blotch does not align with the lower lateral line and aligns with the E1 scale row and does not continue in the E0 scale row. Posteriorly from the midlateral blotch, the stripe is slightly decomposed into two blotches in the respective vertical flank bars. The blotch posterior from the midlateral blotch is centered in the same scale row as the midlateral blotch (i.e. E1 scale row), whereas the second blotch is more elongate along the vertical axis and centered in the E2 scale row, making the impression that the midlateral stripe makes a dorsally directed turn at its posterior end. The arrangement of the bars on the body in essentially the same as described for A. scitulus (Ř íčan & Kullander, 2003).
Dorsal, anal and caudal fins with very small dark spots on interradial membranes. Very small dark spots present also on the bases of some body scales in adult specimens. In juveniles the spotted pattern of the body is much more pronounced, with virtually every scale on the body having a dark spot at its base, including those in the anterior part of the E4 scale row (i.e. as in adult A. scitulus). Juveniles, on the contrary, without spots in unpaired fins.
Color in life. Life fishes have been photographed by Staeck (1998a, 1998b, 2003: p. 64). The ground color of neutral fishes is yellowish to yellow or orange. Many other species of Australoheros have a yellowish ground color, but it is best developed in A. kaaygua. The caudal fin has red dorsal and ventral margins and corners. This character is not unique for A. kaaygua, and can also be seen in populations of A. facetus from Uruguay for example. Also specimens from the Rio Iguaçu tributaries clearly show the red markings on the caudal fin. Breeding animals have the typical Australoheros breeding coloration with the horizontal interruption of the black vertical bars in their dorsal portion between the opercle and the midlateral blotch (Ř íčan & Kullander, 2003; Staeck 1998a p. 82, 1998b: p. 62, 2003: p. 65). The yellow interbar spaces reach all the way down to the belly, even in the breeding coloration (i.e. bars clearly demarcated all the way from D fin base to A fin base). Females in breeding coloration develop a black blotch in the dorsal fin. The yellowish ground color lasts till the female starts to guard free-swimming fry when they lose it and develop a pale, whitish-greyish ground color. This color change is typical for most other cichlasomatine cichlids. Males usually do not change their ground color into white when helping with guarding fry and juveniles, which is also typical for most other cichlasomatine cichlids where the female takes most of the guarding of fry. Staeck (1998b, 2003) describes behavior and spawning under aquarium conditions.
Distribution. Australoheros kaaygua has a disjunct distribution, including tributaries of the Río Iguazú, a tributary of Río Paraná in Brazil and Argentina (Casciotta, Almirón and Gómez, 2006), and tributaries of the Upper Rio Uruguay in Brazil (Fig. 14).
Notes. Juvenile A. kaaygua are similar to juvenile A. scitulus (of about 20 mm SL) in having a characteristic pattern made of rows of spots most marked anteriorly in the E4 scale row (above anterior part of upper lateral line) and also in the two scale rows below the upper lateral line (see Ř íčan & Kullander, 2006). It is unknown whether juvenile A. charrua have these spots as well.
Australoheros kaaygua can be distinguished from both A. scitulus and A. charrua in having 13 caudal vertebrae (vs. 14), and by modal counts of 12 pectoral fin rays (vs. 13), 24 E0 scales (vs. 25), 3 cheek scale rows (vs. 3–4) and in being more deep-bodied.
Additionally distinguished from A. scitulus in having 7 anal spines (vs. 8–9) and 16 dorsal spines (vs. 17), in having a larger interorbital distance, and longer ventral fins (refer to Table 14 for exact values). The difference in the anal fin spine counts is also evident even without counting the spines, since both adult as well as juvenile A. kaaygua can be distinguished from A. scitulus by the origin of the anal fin, which in A. kaaygua originates in the middle of the spot-bearing vertical bar, whereas in A. scitulus the anal fin originates well in front of the spot-bearing vertical bar. The differences in coloration include retaining the spotted flank scales in A. scitulus into adult sizes in contrast to A. kaaygua, where they are mostly present only in juveniles, and adult A. scitulus also develop distinct spots on the head, opercular region, and in the anterior part of the E4 scale row. Spotted unpaired fins are also less common and less pronounced in A. kaaygua than in A. scitulus specimens.
Additionally distinguished from A. charrua in having a shorter snout (refer to Table 15 for exact values) and by having the dorsal margin of the upper lip horizontally aligned with the ventral border of the eye (vs. mouth situated much lower on the head). Also distinguished by having the midlateral stripe posteriorly from the midlateral blotch not as distinctly decomposed into blotches, and also not as distinctly bent upwards. The midlateral stripe posterior from the midlateral blotch is centered in the same scale row as the midlateral blotch (i.e. E1 scale row), and only the last blotch is very high on the body. The midlateral stripe does not continue in the E0 scale row posterior to the midlateral blotch (see description of coloration patterns uniting A. charrua with A. scitulus and A. kaaygua in the description of A. charrua). Also distinguished from A. charrua by having fewer caudal vertebrae (13 vs. 14), fewer E0 scales (24 vs. 25), fewer cheek scale rows (3 vs. 3–4) and pectoral fin rays (12 vs.13), and in being more deep-bodied and with a longer snout (refer to Table 15 for exact values).
scitulus kaaygua caudal vertebrae 14.1±0.4 13.1±2.5 Dorsal fin spines 16.9±0.4 16.1±0.3 Anal fin spines 8.5±0.5 6.9±0.4
Cheek scales 3.6±0.5 3.1±0.3
Pectoral fin rays 13.2±0.5 12.3± 0.5 E 0 scales 24.9±0.5 24.0±0.5 Body depth 46.8±2.0 49.5±1.2 Ventral fin length 28.6±2.2 32.4±3.1 Interorbital width in head length 32.1±3.2 35.2±2.4 charrua kaaygua Caudal vertebrae 13.9±0.4 13.1±2.5 Body depth 46.9±1.5 49.5± 1.2 E 0 scales 25.3±0.5 24.0±0.5 Cheek scales 3.6±0.5 3.1±0.3
Pectoral fin rays 12.9±0.4 12.3±0.5 Snout length in head length 26.3±2.0 28.4±2.3 kaaygua facetus
Ceratobranchial 1 gill rakers 5.8±0.5 7.9±0.7 Obrit diameter in head length 35.5±1.5 30.3±2.4 Anal fin spines 6.9±0.4 6.1±0.3 Pectoral fin rays 12.3±0.5 13.5±0.7 Anal fin rays 7.4±0.6 8.4±0.6 Snout length in head length 28.4±2.3 30.6±3.1 Head length 33.3±1.5 34.5±1.5 Dorsal fin rays 9.3±0.6 10.1±0.5 L2 scales 8.0±0.8 8.6±0.7 Preorbital distance in head length 21.4±3.0 20.3±2.4 kaaygua cf. facetus Body depth 49.5±1.2 44.5±1.5 Ceratobranchial 1 gill rakers 5.8±0.5 7.5±0.5
Caudal peduncle depth 39.9±5.2 48.1±3.5 Caudal peduncle vertebrae 0.4±0.7 1.16±0.4) Preorbital distance in head length 21.4±3.0 16.0±2.5 Ventral fin length 32.4±3.1 28.2±1.4 Head length 33.3±1.5 35.8± 1.0 Interorbital width in head length 35.2±2.4 31.1±2.5 Pectoral fin rays 12.3±0.5 13.0±0.5 Pectoral fin length 30.3±1.4 28.7± 1.0 L1scales 17.5±0.6 15.8±1.2 Head width in head length 52.8±2.0 54.2±2.4 Number of anal fin pterygiophores 12.2±0.4 12.8 0.6 Anal fin spines plus rays 14.3±0.4 14.8±0.6 Supranumerary anal fin pterygiophores 1.5±0.5 1.9±0.4
Anal fin rays 7.4±0.6 7.8±0.5
E0 scales 24.0±0.5 24.4±0.6 kaaygua guarani Anal fin spines 6.9±0.4 6.2±0.4 Ceratobranchial 1 gill rakers 5.8±0.5 7.0±0.0 Obrit diameter in head length 35.5±1.5 32.2±2.3 Cheek scales 3.1±0.3 3.9±0.4 Interorbital width in head length 35.2±2.4 38.7±1.9 Preorbital distance in head length 21.4±3.0 25.6±1.4 Head width in head length 52.8±2.0 55.8±1.4 Pectoral fin rays 12.3±0.5 13±0.0
Supranumerary anal fin pterygiophores 1.5±0.5 1.0±0.0 Body depth 49.5±1.2 48.1± 1.6 Among the A. facetus -like species, this species is most similar to the more slender bodied A. minuano (in having a small terminal mouth, 6 C1 gill rakers, 12 pectoral fin rays). Distinguished from A. facetus, A. cf. facetus and A. guarani by a different head shape, and a smaller, terminal mouth (vs. larger, upturned mouth in A. facetus and A. cf. facetus and a larger and subterminal mouth in A. guarani), in having fewer C1 gill rakers (5–6 vs. 7–8), and modally 12 pectoral fin rays (vs. 13). Distinguished from the A. facetus -like species in coloration characters, as explained in the description of A. charrua. Additionally distinguished from all, except A. guarani, by only three abdominal bars (vs. four), from all except A. cf. facetus by 7 anal spines (vs. 6), and from all except A. facetus in being more deep-bodied. For all meristic and morphometric differences between A. kaaygua and the A. facetus -like species see Tables 16–19.
Distinguished from A. forquilha and A. tembe by having 13 caudal vertebrae (vs. 14 or 15), by a shorter caudal peduncle including 1 or none vertebra (vs. modally 2 or 3), 7 anal fin spines (vs. 6), modally 12 pectoral fin rays (vs. 13–14), 24 E0 scales (vs. 26), 3 cheek scale series (vs. 4 to 5) and 5–6 C1 gill rakers (vs. 7–8 in A. forquilha and A. tembe).
kaaygua minuano Body depth 49.5±1.2 46.9±1.2 Anal fin rays 7.4±0.6 8.4¡À0.5 Cheek scales 3.1±0.3 4.0±0.0 Anal fin spines 6.9±0.4 6.3±0.5 Preorbital distance in head length 21.4±3.0 16.7±2.4 Head length 33.3±1.5 35.9±1.1 L2 scales 8.0±0.8 8.8±0.4
description: Published as part of An, Old Ř Ich Ř Í Č & Kullander, Sven O., 2008, The Australoheros (Teleostei: Cichlidae) species of the Uruguay and Paraná River drainages, pp. 1-51 in Zootaxa 1724 on pages 27-34, DOI: 10.5281/zenodo.181173