Crenicichla Piálek, An, Casciotta & Almirón, 2010, new species
Creators: name: Piálek, Lubomír
name: An, Old Ř Ich Ř Í Č
name: Casciotta, Jorge
name: Almirón, Adriana
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Cichlidae
Crenicichla

description: Crenicichla hu, new species
(Figs. 2–5)
Holotype. MACN-ict 9429, 118.0 mm, Argentina, Misiones, río Paraná basin, arroyo Piray–Miní, 26°20'00.3"S 53°52'30.0"W, Nov 2007, O. Ř íčan et al. (Fig. 2).
Paratypes. All from Argentina, same data as the holotype. MACN-ict 9430, 17 ex., 76.9–153.0 mm. AI 261, 4 ex., 96.3–110.0 mm. AI 262, 1 ex. (C&S) 93.9 mm, same data as holotype (Figs. 3–4).
Diagnosis. Crenicichla hu is distinguished from all known species of the La Plata basin and adjacent coastal rivers by the following combination of characters: 1. dark grey or dark brown to black color of body and fins, 2. 7 to 9 black irregular blotches on the flank, 3. 47–54 scales in row E1, 4. the dorsal fin of adult females with a color pattern formed of black and white longitudinal stripes and/or blotches.
Since the molecular analysis confirmed close relations between C. hu and its biogeographic congeners from the Paraná basin (Fig. 1), a detailed comparative analysis was performed on all 13 known species inhabiting the Paraná drainage basin, either exclusively or partly:
Crenicichla hu is distinguished from C. britskii and C. lepidota (both C. saxatilis group) by the absence of the distinctive humeral spot vs. a humeral spot present (synapomorphy of the group). Crenicichla hu is distinguished from C. haroldoi by the absence of dots on lateral line scales vs. brown dots present on each lateral line scale. It differs from C. iguassensis and C. tesay in the absence of small dots on the flank vs. numerous scattered small dots present. Crenicichla hu is distinguished from C. jaguarensis, C. vittata, and adults of C. mandelburgeri by the absence of a lateral band vs. a lateral band present. It differs from C. jaguarensis in the absence vs. presence of the caudal spot. Further, Crenicichla hu differs from C. mandelburgeri and C. niederleinii in the absence vs. presence of the narrow vertical double-bars on the flank. It is also distinguished by a low number of scales in a lateral row, 47–54 vs. 56–65 in C. niederleinii and 78– 85 in C. vittata. Crenicichla hu differs from C. jupiaensis in the absence vs. presence of numerous narrow vertical bars on the flank, a well developed (but composed of spots) suborbital stripe vs. reduced to a few spots posteriorly to the orbit, a cheek bearing 4 to 6 scale rows vs. a naked cheek, and the absence vs. presence of a thin black line on the posterior margin of the preopercle. Crenicichla hu lacks several regular parallel rows of small dark spots vs. present in C. scottii. The new species is distinguished from C. semifasciata (C. reticulata group) by having about half of the caudal fin scaled vs. this fin scaled over most of its surface. C. hu further has the ascending arm of the premaxilla longer than the dentigerous one vs. shorter in C. semifasciata. Finally, C. hu is distinguished from C. yaha by the head depth 17.9–20.8% vs. 15.1–18.1% of SL, and lower jaw slightly prognathous vs. jaws isognathous or upper jaw slightly prognathous.
Description. Morphometric data of the holotype and paratypes is given in Table 3. Body elongate, depth 21.5 to 25.6% of SL (Fig. 2). Head slightly deeper than wide. Snout short, bluntly pointed in lateral view, 2.5 to 3.0 times in HL. Lower jaw slightly prognathous. Tip of maxilla not reaching anterior margin of orbit in most specimens (reaching in four specimens, MACN-ict 9429). Lower lip widely interrupted medially. Nostrils dorsolateral, nearer anterior margin of orbit than snout tip. Posterior margin of preopercle weakly serrated (21 ex.*) or smooth (3 ex., MACN-ict 9430). Scales on flank strongly ctenoid. Head scales cycloid. Predorsal scales small, superficially embedded in skin. Prepelvic scales smaller than predorsal ones.
Interopercle naked. Cheek scaled, 4 to 6 scales below eye embedded in skin. Scales in E1 row 47(1), 51(2), 52(4), 53(5), 54(9*). Scales in transverse row 10/14(1), 11/13(1), 11/14(7), 11/15(2), 11/16(3*), 11/17(3), 12/ 13(1), 12/14(2), 12/15(1). Three scale rows between lateral lines. Upper lateral line scales 18(1), 19(1), 21(3), 22(8), 23(4*), 24(2), 25(2). Lower lateral line scales 10(1), 11(7), 12(5), 13(1), 14(5), 15(2*). Dorsal, anal, pectoral and pelvic fins naked. Dorsal fin XVIII,10(1); XX,12(2); XX,13(1); XXI,10(3*); XXI,11(8); XXI, 12(4); XXII,11(1). Anal fin II,10(1); III,8(2); III,9(14*); III,10(3). Pectoral fin 15(10*), 16(11). Caudal-fin squamation extending almost to middle of fin in larger specimens, no more than the basal third of caudal fin in smaller ones. Soft-dorsal fin rounded or pointed tip, surpassing caudal-fin base. Tip of anal fin reaching caudal-fin base (not reaching in three specimens, AI 261 and MACN-ict 9429). Caudal fin rounded. Pectoral fin rounded, almost reaching the tip of pelvic fin. Microbranchiospines present on second through fourth gill arches. Gill rakers externally on first gill arch: 1 on epibranchial, 1 on angle, and 8 on ceratobranchial. Three to five patches of unicuspid teeth on fourth ceratobranchial. Lower pharyngeal tooth plate with unicuspid recurved and curved crenulated bicuspid teeth, those of posterior and medial row larger than remaining ones (Fig. 5). Upper pharyngeal tooth plate with unicuspid and bicuspid teeth. Frashed zone bearing one concavity with small unicuspid teeth. Premaxillary ascending process longer than dentigerous one. Premaxilla with 24(1) unicuspid teeth on outer row, larger than inner ones. Five teeth rows near symphysis. Dentary with 25(1) unicuspid teeth on outer row, 4 rows near symphysis. Total vertebrae 35 (1 C&S ex.). Premaxillary and dentary outer row teeth slightly movable, inner ones fully depressible.
Coloration in alcohol. Background of body deeply dark, almost black in large specimens; smaller ones (75–95 mm) dark brown. Deep grey preorbital stripe between anterior margin of orbit to snout tip, only visible in smaller specimens. Postorbital stripe between posterior margin of orbit to preopercle distal margin, deep grey; only visible in smaller specimens. Suborbital stripe black almost reaching ventral margin of cheek; wide (up to six dots) and fragmented. Flank with 7 to 9 black irregular blotches just below upper lateral line and reaching faintly dorsal-fin base. Posteriormost blotch extending or not onto caudal peduncle. Dorsal, anal, and caudal fins dark grey or black, dorsal and anal fins with numerous dark scattered dots on their surface, also present in caudal fin in smaller specimens. Dorsal fin (females) with an irregular color pattern formed by black and white longitudinal stripes and blotches (3 ex., AI 261 and MACN-ict 9430; Fig. 4) or a black longitudinal stripe (sometimes reduced to a single blotch) with white margin (2 ex.*, MACN-ict 9429; Fig. 2). Caudal fin with a black subcircular spot well separated from base of fin, just above midline of caudal fin. Pectoral and pelvic fins smoky.
Coloration in live specimens. Same as color in alcohol (Figs. 3–4). Live specimens lack almost all carotenoid or physical reflective colors, the overall color is dark grey or dark brown to black. Some female specimens show a faint orange area behind the pectoral fin. Outline of the black areas in the dorsal fin of females milk-colored (Fig. 4).
Ecological notes. The arroyo Piray–Miní (the type and only-known locality) has clear and rapidly flowing water. The depth of the arroyo Piray–Miní is variable, 0.20 to 1.40 m. The bottom consists of mud, sand, and mostly stones. Some areas have scarce submerged vegetation (Figs. 6–7).
Etymology. The specific epithet hu is a Guaraní word hû that means black in allusion to the ground color of the body and fins.
Discussion. Molecular phylogeny divides the Misioneran crenicichlas into several clades (Fig.1). The basal-most species is C. lepidota (C. saxatilis group; Fig. 1; tree additionaly rooted with Satanoperca jurupari and Astronotus ocellatus; see Methods). The two philosophically distinct computing methods (MP, BA) inferred a robust phylogenetic hypothesis of nearly identical topologies that supports the biogeographic foundation of the recognized species groups. All species from the Misioneran part of the Paraná drainage basin (C. hu, C. tesay, C. yaha, and C. mandelburgeri) were grouped together in one clade with conclusively high support (Fig. 1; Paraná endemic species; bootstrap, 96; PP, 1.00). The newly described Crenicichla hu is recovered in a basal position of this clade. Crenicichla mandelburgeri appears non-monophyletic (see below).
The position of C. vittata inhabiting both the Paraná and the Uruguay basins differs between the BA and MP hypotheses, in the latter forming a monophyly together with the endemic Paraná species (Fig. 1; bootstrap, 66). The morphologically distinct Crenicichla species from the Uruguay basin formed two independent clades (Fig. 1; C. missioneira and C. scottii groups). Two species from the coastal rivers (C. lacustris, C. punctata) do not form a monophyletic lineage in either of the two phylogenies.
The phylogeny of a few species of Crenicichla from southern South America was recently studied by Kullander et al. (in press). That study supports virtually the same relationships between the above-mentioned clades. The endemic Paraná species group was represented in their analysis by only one taxon (C. iguassuensis) as were the coastal-river drainages (C. punctata). The Uruguay basin was represented by the C. scottii group (C. scottii) and the C. missioneira group (C. missioneira, C. minuano, C. celidochilus, C. empheres, C. tendybaguassu). There is thus no overlap with our taxon sampling of the endemic Paraná clade.
Evaluating the uncorrected pairwise divergences between the gene sequences of Crenicichla hu and the other species, the supposed higher evolutionary rate in the Geophagini tribe of cichlids must be taken in account (Farias et al. 1999, 2000; Pereyra & García 2008). Referring to ND2 sequences, the lowest divergence between a haplotype of C. hu and a haplotype of the nearest species (C. mandelburgeri C44) is 3.3% (Table 2). On the other hand, substantially lower values of divergences between formerly described species can be found (e.g., C. missioneira C36 vs. C. minuano C80, 0.6%; C. tesay C1 vs. C. mandelburgeri C51, 1.0%; C. yaha C5 vs. C. mandelburgeri C44, 1.0%). Despite the little-known divergence rate in Geophagini (López-Fernández et al. 2005), molecular divergences between the newly described species and its phylogenetic neighbours are substantial.
With the newly described C. hu, fourteen species of Crenicichla have now been recorded from the río Paraná basin. Some of them (i.e. C. britskii, C. haroldoi, and C. jaguarensis) are restricted to the Upper Paraná basin (Resende 2003; Reis et al. 2003). Crenicichla jupiaensis and C. niederleinii are found both in the Upper and Middle Paraná basin. Several species (i.e. C. lepidota, C. mandelburgeri, C. scottii, C. semifasciata and C. vittata) inhabit only the lower–middle part of the river; C. vittata occurs also in the Uruguay basin. Crenicichla iguassuensis and C. tesay are only present in the Iguazú basin. Crenicichla yaha is registered from the arroyo Urugua–í (Paraná basin) and Iguazú basin above the Cataratas del Iguazú.
The high diversity of ichthyofauna in the Argentinean province of Misiones has already been stressed. Three new Crenicichla species have recently been described from the río Paraná tributaries in Misiones (C. yaha, C. tesay, and C. hu), and several additional putatively new species are known to us from these tributaries (pers. obs).
We also confirm the presence of Crenicichla mandelburgeri in Misiones. Our material was compared with material from the type localities of C. mandelburgeri (both morphology and the ND2 gene sequences; not shown). This taxon, however, demonstrates geographical variation as well as phylogeographic structure (Fig. 1), and we thus cannot rule out the presence of a species complex; the specimens from Piray-Guazu (haplotypes C15, C17) that infringe on the monophyly of this species are therefore referred to as C. cf. mandelburgeri.
Based on our field observations, Crenicichla missioneira, C. minuano and C. gaucho, described from the Middle río Uruguay in Rio Grande do Sul, Brazil and also cited by Lucena & Kullander (1992) from Misiones, are quite common in the río Uruguay tributaries in Misiones. Crenicichla hadrostigma, described from the Upper río Uruguay in Santa Catarina, Brazil is known so far from one locality in Misiones (Lucena 2007), confirming the possibility of finding additional Upper Uruguay Crenicichla species in Misiones. On this note, Lucena & Kullander (1992) also cite C. tendybaguassu from Misiones.
So far there are no records in Misiones of four Crenicichla species which are known from the Upper río Uruguay basin in Brazil (C. prenda, C. empheres, C. igara and C. jurubi), whose boundary with the Middle río Uruguay is recognised as being at the Salto Moconá (Yucumã), just downstream from the río Pepirí–Guazú which forms the eastern border between Misiones, Argentina and Santa Catarina, Brazil (Zaniboni Filho & Schulz 2003). The ranges of these species could thus primarily be outside of Misiones as they are also not known from the Middle río Uruguay in Rio Grande do Sul, Brazil. However, the presence of these species in Misiones cannot be ruled out (see C. hadrostigma and C. tendybaguassu above).
Despite its small size, the province of Misiones shows biogeographic structuring which cannot be explained merely by diversity on a broader scale. Both the río Paraná and río Uruguay tributaries in Misiones are divided from the main rivers by waterfalls close to their mouths, but the northern tributaries of the Paraná in particular and the Iguazú itself in Misiones have a significant number of endemics which are so far not known outside of Misiones (i.e. Paraguay or Brazil). Among Crenicichla these are C. tesay from río Iguazú and C. yaha from río Iguazú and arroyo Urugua–í and C. hu from arroyo Piray–Miní (Fig. 7). Two putative new species are further known from the arroyo Urugua–í (pers. obs.), which is located between the río Iguazú and arroyo Piray–Miní. These three drainages together with arroyo Aguaray–Guazú form the northern part of Misiones. From the southeastern-most point of this part of Misiones starts the watershed between the río Paraná and río Uruguay. Tributaries of the río Paraná from here to the southeast (starting with arroyo Piray– Guazú, Fig. 7) have a diferent fauna of Crenicichla (dominated by C. mandelburgeri). A very similar pattern is also observed among Australoheros Ř íčan & Kullander, but with the exception that south from arroyo Piray–Miní there are so far no known species of Australoheros in the río Paraná tributaries in Misiones (A. kaaygua Casciotta et al., A. tembe (Casciotta et al.) [and likely A. guaraní Ř íčan & Kullander] are known again only from the northern tributaries).
Comparative material. A list of comparative material of C. scottii and C. vittata is available in Casciotta (1987). In addition, the following material was studied: Crenicichla hadrostigma: Argentina. AI 220, 1 ex., 72.8 mm, Misiones, Itacaruare, río Uruguay basin. Crenicichla iguassuensis: Brasil. FMNH 54159 (holotype), 137 mm, Porto Uniao da Victoria, Rio Iguassu. Crenicichla jupiaensis: Argentina. AI 226, 2 ex., 87.7–93.0 mm, Corrientes, río Paraná at Yahapé. AI 227, 1 ex., 60.7 mm, Corrientes, río Paraná at Yahapé. Crenicichla lepidota: Argentina. MACN-ict 5067, 4 ex., 67.7–113.4 mm, Misiones, Represa Estación Experimental Cerro Azul. FML 0 0 528, 1 ex., 111.5 mm, Salta, Luna Muerta, Hickman. MACN-ict 3656, 2 ex., 116.0– 165.7 mm, Formosa, Riacho de Oro. MACN-ict 7275, 1 ex., 151.6 mm, Chaco, Esteros del Palmar. FML 0 0 312, 1 ex., 138.0 mm, Corrientes, Isla Apipé Grande, Ituzaingó. MACN-ict 4091, 1 ex., 98.4 mm, Entre Ríos, río Uruguay, Concepción del Uruguay. MACN-ict 2314, 6 ex., 59.9–104.2 mm, Buenos Aires, Isla Martín García. Uruguay. MNHNM 2087, 1 ex., 72.9 mm, Departamento Colonia, arroyo Limetas. Crenicichla cf. mandelburgeri: MACN-ict 9439, 2 ex., 83.7–93.0 mm, Misiones, arroyo Guaruhape en ruta 220, río Paraná basin. MACN-ict 9440, 2 ex., 72.6–82.3 mm, Misiones, arroyo Cuñapirú, in route 223 near Ruiz de Montoya, río Paraná basin. MACN-ict 9441, 7 ex., 56.0–93.0 mm, Misiones, arroyo Cuñapirú (arroyo Tucangua), río Paraná basin. MACN-ict 9442, 2 ex., 102.2–208 mm, Misiones, arroyo Chapa, ruta 6, río Paraná basin. Boggiana ocellata: Paraguay. MSNG 33700 (holotype), 257.5 mm, Puerto 14 de Mayo, Bahía Negra, Chaco Boreal. Crenicichla semifasciata: Argentina. MACN-ict 3683, 1 ex., 68.8 mm, Formosa, Riacho de Oro. MACN-ict 6239, 1 ex., 176,6 mm, Entre Ríos, arroyo Curupí. Crenicichla tesay: MACN-ict 9016 (holotype), 115.1 mm, Argentina, Misiones, río Iguazú basin, arroyo Verde. Crenicichla yaha: Argentina, Misiones. MACN-ict 8924 (holotype), 103.7 mm, arroyo Urugua–í in Isla Palacios. AI 199, 1 ex., 116.6 mm, río Iguazú basin, arroyo Benavente. MTD-F 30606 (paratype), 1 ex., 105.9 mm, arroyo Urugua–í in ruta provincial 19, Parque Provincial Islas Malvinas. AI 200 (paratype), 1 ex., 135.8 mm SL, arroyo Uruzú (affluent of A. Urugua–í) in ruta provincial 19, Parque Provincial Islas Malvinas. AI 202 (paratypes), 4 ex., 1 (C&S) 37.4– 48.5 mm, arroyo Urugua–í in Isla Palacios.
description: Published as part of Piálek, Lubomír, An, Old Ř Ich Ř Í Č, Casciotta, Jorge & Almirón, Adriana, 2010, Crenicichla hu, a new species of cichlid fish (Teleostei: Cichlidae) from the Paraná basin in Misiones, Argentina, pp. 33-46 in Zootaxa 2537 on pages 38-44, DOI: 10.5281/zenodo.196655