Gymnogeophagus pseudolabiatus, Malabarba & Malabarba & Reis, 2015

Malabarba, Luiz R., Malabarba, Maria Claudia & Reis, Roberto E., 2015, Descriptions of five new species of the Neotropical cichlid genus Gymnogeophagus Miranda Ribeiro, 1918 (Teleostei: Cichliformes) from the rio Uruguay drainage, Neotropical Ichthyology (Neotrop. Ichthyol.) 13 (4), pp. 637-662 : 640-644

Gymnogeophagus pseudolabiatus , new species u r n:l s i d:z o o b a n k.o rg:a c t: 3D1C A 0 6 8-3 0 0 0-4 4 0 2-A 4 5A - B9DFF11B8021

Figs. 4 , 5 , 6a

Gymnogeophagus sp. C . - Wimberger et al., 1998 (molecular phylogeny).

Gymnogeophagus cf. gymnogenys complex - Clade 2. - Pereyra & García, 2008 (molecular phylogeny).

Holotype. MCP 35027 , male, 92.3mm SL, Brazil, Rio Grande do Sul, Santana do Livramento, rio Sarandi III, tributary of rio Quaraí , a tributary of rio Uruguay on road from Santana do Livramento to Quaraí , 30°34’40”S 56°04’08”W, 10 Dec 1992, R. E. Reis, P. H. Wimberger & J. F. P. Silva.

Paratypes. Brazil: Rio Grande do Sul: MCP 16123 (24, 46.9-91.1 mm SL), MCP 18294 (1, 93.9 mm SL), UMMZ 225451 (10, 53.1-92.6 mm SL), collected with the holotype. MCP 18371 (14, 44.6-69.5 mm SL), same locality as the holotype, 21 Nov 1995, J. P. Silva and others. MCP 11228 (14 alc., 3 c&s, 42.5-87.0 mm SL), arroio Garupá, between Alegrete and Quaraí, Quaraí, approx. 30°04’S 56°14’W, 11- 12 Nov 1986, C. A. S. Lucena, L. A. Bergman & P.Azevedo. MCP 11462 (1, 93.8 mm SL), tributary of rio Quaraí-Mirim, on road from Quaraí to Alegrete, approx. 30°18’S 56°23’W, 12 Nov 1986, C. A. S. Lucena, L. A. Bergman & P. Azevedo. MCP 13664 (1, 64.1 mm SL), rio Garupá, between Uruguaiana and Quaraí, 30°07’24”S 56°25’29”W, 22 Jul 1986, R. E. Reis, L. A. Bergman & P. Azevedo. MCP 19566 (2, 31.8- 27.2 mm SL), rio Quaraí-Mirim on road from Uruguaiana to Quaraí, Quaraí, 30°15’29”S 56°30’37”W, 13 Sep 1996, W. A. Santos, J. P. Silva, V. Bertaco, E. Vidal and others. MCP 35035 (17, 67.3- 39.5 mm SL) arroio Garupá tributary of rio Quaraí, on road from Quaraí to Harmonia, 33 km NE of Quaraí, Quaraí, 30°09’45”S 56°14’08”W, 25 Apr 2004, R. E. Reis, A. R. Cardoso, M. Abreu, F. Ribeiro. MCP 35036 (18, 30.1-86.5 mm SL) creek tributary of rio Quaraí, on road from Quaraí to Baltazar Brum railroad station, 30°21’52”S 56°26’23”W, 25 Apr 2004, R. E. Reis, A. R. Cardoso, M. Abreu, F. Ribeiro. MCP 35277 (10, 70.4- 25.5 mm SL) arroio Mata-olho tributary of rio Quaraí, on road from Livramento to Quaraí, Quaraí, 30°32’11”S 56°08’28”W, 24 Apr 2005, R. E. Reis, A. R. Cardoso, M. Abreu, F. Ribeiro. Uruguay: Artigas: MCP 17593 (12, 46.0- 81.1 mm SL), arroyo Arumbeba, about 22 km SE of Artigas, 30°30’02”S 56°25’ 02”W, 20 Feb 1995, R. E. Reis & C. S. Fontana. UFRGS 7754 (16, 51.6-95.9 mm SL), arroyo Cuaró Grande on Ruta 4, tributary of rio Quaraí, Artigas, 30°47’03”S 56°46’54”W, 8 Sep 2005, V. Bertaco, F. Cantera, J. Ferrer & L. R. Malabarba. UFRGS 7961 (26, 90- 33.9 mm SL), arroyo Yucutujá on Ruta 3, Artigas, 57°17’48”W 30°26’18”S, 9 Sep 2005. UFRGS 8001 (76, 81.5- 32.1 mm SL), arroyo Tres Cruces Grandes on Ruta 4, rio Quaraí basin, Artigas, 30°35’ 33”S 56°37’ 36”W, 8 Sep 2005. UFRGS 8503 (56, 98.4- 25.5 mm SL), arroyo Pelado on Ruta 4, rio Quaraí basin, Artigas, 30°39’33”S 56°40’29”W, 8 Sep 2005. ZVCP 10180 (10, 26.2-65.5 mm SL), arroyo Lemos, 30°19’37.5”S 56°34’31.1”W, Aug 2006, M. Loureiro, Teixeira de Mello, González & Quintans.

Diagnosis. Gymnogeophagus pseudolabiatus differs from all congeners, except G. labiatus , by the presence of thick, extremely well developed lips, with the lower lip deeply notched medially. It can be distinguished from G. labiatus by the presence of a dark band extending posteroventrally from the dorsal-fin origin (absent in G. labiatus ), and by the dorsal, anal and caudal-fin color patterns, where fins are partially or completely covered with well-defined circular dots (vs. small longitudinal stripes).

Description. Morphometric data summarized in Table 1. Body elongated, laterally compressed. Dorsal profile of head approximately straight between mouth and interorbital area and convex from interorbital region to dorsal-fin origin. Predorsal body profile modified in adult males that may show moderate adipose hump ( Figs. 4a , 5a ). Dorsal-fin base slightly convex. Caudal peduncle longer than deep, with dorsal and ventral profiles slightly concave.

Snout pointed, straight dorsally and ventrally in lateral aspect; narrow and anteriorly rounded in dorsal aspect. Upper and lower lips thick, large; extremely developed in adult males. Eye small, close to dorsal profile of head in juveniles and far from it at least one-half eye diameter in specimens larger than 70 mm SL; eye slightly posterior or near middle of head length. Interorbital area convex, more strongly in large specimens; interorbital width smaller than eye diameter in young (30-65 mm SL) and progressively larger than eye diameter in larger specimens. Posterior tip of maxilla not reaching vertical line crossing anterior margin of eye. Upper jaw longer than lower jaw.

Body scales large and ctenoid, smaller around pectoral fins; scales cycloid in preventral area. Caudal fin with single series of small ctenoid and elongated scales between contiguous rays reaching proximal third to half length of fin in both upper and lower lobes. Other unpaired fins without scales. Cheek scales cycloid in 4 to 6 rows; cheek naked anteroventrally. Upper half of opercle scaled; one vertical row of ctenoid scales in its anterior margin, not observable in all specimens. Subopercular scales ctenoid in single row. Upper lateral line 15(2), 16(1), 17*(8); lower lateral line 7*(4), 8(2), 9(4), 10(5), 11(2), 12(1), usually with 1 to 5 small perforated scales continuing onto caudal-fin base. Scales between upper lateral line and dorsal fin 4(14), 5*(5). Scales between upper lateral line and anal fin 8*(16), 9(3). E1 scales 25*(1), 26(10), 27(6), 28(2).

Dorsal-fin spines 12(1), 13(8), 14*(9), 15(1); dorsal-fin soft rays 9*(3), 10(15), 11(1). First dorsal-fin spine inserted at vertical line across posterior bony margin of opercle or slightly anterior to it in larger specimens. Soft dorsal fin in young and females rounded, reaching to or almost reaching caudal-fin base. Soft dorsal fin in mature males pointed, with 4th ray produced and reaching proximal third to almost end of caudal fin. Anal-fin with three spines and 7*(6), 8(12), 9(1) soft rays. Anal-fin origin under or slightly posterior to last dorsal-fin spine; soft portion nearly rounded in young and females and clearly pointed in males. Pectoral fin pointed, more strongly in adults; 3rd and 4th rays longest, reaching vertical crossing anal-fin origin in young and females and passing that point in males. Pelvic fin pointed, more conspicuously in adult males; 2nd soft ray longest reaching region between anal opening and anal-fin origin in young and females and passing anal-fin origin in adult males. Caudal-fin posterior margin concave.

Jaw teeth small, conical, strongly recurved. Upper jaw with outer regular row of nearly 20 teeth in each premaxilla (number increasing with specimen size) and 3 or 4 indistinct irregular inner tooth bands. Lower jaw with tooth band arranged in 3-4 irregular rows; teeth larger near symphysis. Lower limb of first gill arch with 7-8 gill rakers; upper limb lobed (as in other geophagines) with 5-6 gill rakers in its margin.

Lower pharyngeal tooth plate wide; length of bone 85.7% of width; teeth covering whole occlusion surface; 21 teeth in posterior row, 17 on median row. Teeth on posterior and medial rows larger than remaining ones. Posterolateral teeth small and laterally compressed, with slightly recurved tips; posteromedial teeth much larger, cylindrical with medial, blunt cusps of molariform aspect ( Fig. 6a ).

Vertebrae 12+15(1), 12+17(1), 13+16(1) in three cleared and stained specimens.

Color in alcohol. Mature males ( Fig. 4a ): base color of body dark brown above longitudinal series of scales bearing lower lateral line, becoming yellowish tan below pectoral-fin insertion and in prepelvic area. Six to 9 vertical bars clearly discernible along midventral surface of body, variable in shape, distributed between pectoral-fin base and caudal peduncle. Midlateral spot not well defined, on scales 8-10 of scale row just below upper lateral line and on scales 7-9 of E1 scale row. Dark band in front of dorsal-fin origin, extending ventrally and slightly posteriorly, almost reaching first scales of upper lateral line. Head light brown, with series of conspicuous black markings surrounding eye ventrally and posteriorly, partially covering opercle. Faint vertical dark band covering cheek. Isthmus and branchiostegal membrane brownish gray. Pectoral fin hyaline. Pelvic fin dark brown. Distal border of entire dorsal fin dark brown. Spinous dorsal fin faint brown with small, narrow and inconspicuous white stripes. Soft dorsal fin faint brown covered with large number of well-defined white spots. About half distal length of anal-fin rays and spines dark brown, without additional distinct marks. Proximal half of anal-fin rays covered with small and conspicuous white dots. Caudal fin covered with white dots along almost its entire length.

Preserved coloration of females and juveniles not clearly distinct from that described for males ( Fig. 4b ), except for isthmus and branchiostegal membrane light yellow, instead of brown as observed in males. Presence of conspicuous vertical dark band covering cheek, below eye.

Color in life. Base color of dorsal region of body in males ( Fig. 5a ) olivaceous with longitudinal series of bright blue spots. Head largely yellowish green, with lips and lower jaw region pale gray. Adipose hump light brown. Red marks concentrated on opercular region and scattered over nape and anterodorsal scales. Numerous small roundish to elongate light blue spots posterior and ventral to eye and on opercle. Lateroventral portion of body yellowish brown, more intense around pectoral-fin base; yellow pale to white along isthmus and midventral regions. Anterior part of dorsal fin yellow, with hyaline thin stripes; posterior part red with numerous relatively large hyaline spots. Dorsal-fin distal margin dark black dorsally and reddish orange posteriorly. Pectoral-fin hyaline and pelvic-fin dark gray. Anal fin reddish orange proximally with numerous hyaline spots, slightly smaller than those from dorsal fin. Anal fin pale red distally with dark gray distal margin. Caudal fin orange proximally and faint red distally with numerous light spots extending along its middle region. Tips of dorsal and ventral lobes dark gray.

Color in life of females ( Fig. 5b ) similar to that described for males, but paler. Most clear differences refer to light brown and silvery color of opercle and below pectoral fin regions, instead of yellow as observed in males. Conspicuous vertical dark band from posterior eye margin to cheek.

Distribution. Gymnogeophagus pseudolabiatus is known from the rio Quaraí and its tributaries, along the frontier of Brazil and Uruguay in the middle rio Uruguay drainage ( Fig. 1 ).

Ecology. This species is found exclusively in stone bottom habitats covered with stones and rocks of all sizes, found along the rio Quaraí and its tributaries ( Fig. 7 ).

Etymology. From the Greek pseudos, meaning false, and labiatus , in reference to a congener species that also presents well developed lips. A noun in apposition.

Conservation status. Gymnogeophagus pseudolabiatus is relatively frequent and abundant in the rio Quaraí basin. Despite its Extent of Occurrence (EOO) is approximately 4,500 square kilometers, no specific threats were detected, and the species can be categorized as Least Concern (LC) according to IUCN criteria ( IUCN, 2014).

Figures

Fig. 4. Gymnogeophagus pseudolabiatus: top, holotype, male, MCP 35027, 92.3 mm SL, rio Sarandi III, on the road from Santana do Livramento to Quaraí, Santana do Livramento, Rio Grande do Sul, Brazil; bottom, paratype, male, MCP 35036, 81.4 mm SL) creek tributary of rio Quaraí, on road from Quaraí to Baltazar Brum railroad station, Rio Grande do Sul, Brazil.

Fig. 5. Gymnogeophagus pseudolabiatus: top, paratype, male, UFRGS 7754, 102.0 mm SL, arroyo Cuaró Grande on Ruta 4, tributary of rio Quaraí, Artigas, Uruguay; bottom, paratype, female, UFRGS 7754, 80.5 mm SL, arroyo Cuaró Grande on Ruta 4, tributary of rio Quaraí, Artigas, Uruguay.

Fig. 6. Lower pharyngeal tooth plates in occlusal view: a, G. pseudolabiatus, MCP 11228, 71.6 mm SL; b, G. mekinos, MCP 11251, 84.2 mm SL; c, G. constellatus, MCP 10827, 91.4 mm SL; d, G. missioneiro, MCP 12725, 59.3 mm SL; e, G. lipokarenos, MCP 12991, 89 mm SL. Scale bars = 1 mm.

Fig. 1. Rio Uruguay and adjacent drainages showing the distribution of the examined specimens of Gymnogeophagus lipokarenos (dark blue), G. missioneiro (light blue), G. constellatus (red), G. pseudolabiatus (orange), and G. mekinos (yellow). Stars represent the type localities.

Fig. 7. Rio Sarandi III, on the road from Santana do Livramento to Quaraí, Santana do Livramento, Rio Grande do Sul, Brazil, type locality of Gymnogeophagus pseudolabiatus.