Corydoras lacrimostigmata, Tencatt & Britto & Pavanelli, 2014

Tencatt, Luiz F. C., Britto, Marcelo R. & Pavanelli, Carla S., 2014, A new species of Corydoras Lacépède, 1803 (Siluriformes: Callichthyidae) from the upper rio Paraná basin, Brazil, Neotropical Ichthyology 12 (1), pp. 89-96 : 91-94

Corydoras lacrimostigmata , new species Figs. 1 , 2a

Corydoras flaveolus not Ihering, 1911. - Graça & Pavanelli, 2007: 10, 113, 114 [ Brazil, Paraná State, checklist, identification key, brief description, distribution, maximum standard length, photo in lateral view]

Holotype. MNRJ 40725 , 31.8 mm SL, Brazil, Paraná, Cândido deAbreu, rio Maria Flora, tributary to rio Ubazinho , rio Ivaí basin, 24º36’32”S 51º15’32”W, 9 Mar 2013, L.F.C. Tencatt, G.C. Deprá & F. T. Mise.

Paratypes. All collected in Brazil, Paraná State, Cândido de Abreu, rio Ivaí basin, except when noticed. MCP 47851, 5 , 25.8-29.8 mm SL, rio Nestor , 24º32’26”S 51º20’09”W, 22 Nov 1994, Nupélia staff. MNRJ 40726 , 16 , 25.7-34.3 mm SL, rio Nestor , 24º28’S 50º54’W, 22 Nov 1994, Nupélia staff. NUP 1408 , 5 , 26.1-31.2 mm SL, rio Nestor , 24º32’26”S 51º20’09”W, 22 Nov 1994, Nupélia staff. NUP 1436 , 9 , 26.0- 27.6 mm SL, rio Nestor , 24º32’05”S 51º19’39”W, 22 Nov 1994, Nupélia staff. NUP 1446 , 26 , 17.5-34.3 mm SL, rio Nestor , 24º28’S 50º54’W, 22 Nov 1994, Nupélia staff. NUP 5484 , 2 , 27.2-28.3 mm SL, Prudentópolis, rio Barra Grande , 24º58’41”S 51º07’34”W, 3 Apr 2007, C. H. Zawadzi & W. J. da Graça. NUP 14657, 3 c&s, 30.9-34.5 mm SL, rio Nestor , 24º32’05”S 51º19’39”W, 22 Nov 1994, Nupélia staff. ZUEC-PIS 7550 , 3 , 26.5-30.5 mm SL, rio Nestor , 24º32’05”S 51º19’39”W, 22 Nov 1994, Nupélia staff. NUP 3976 , 2 , 26.5 -30.0 mm SL ; same data as the holotype .

Diagnosis. Corydoras lacrimostigmata can be distinguished from its congeners, with exception of C. carlae , C. ehrhardti , C. flaveolus , C. longipinnis , C. nattereri , C. paleatus , and C. vittatus , by the presence of three nasal pores (vs. two). The new species can be distinguished from C. carlae , C. ehrhardti , C. longipinnis , C. nattereri , C. paleatus , and C. vittatus by the presence of four to six small rounded black blotches along the midline of flank (vs. midline of flank with three large black blotches in C. carlae , C. ehrhardti , C. longipinnis , and C. paleatus ; longitudinal dark stripe in C. nattereri ; and anterior portion spotted and posterior portion with posterior margin of plates blackened, forming a rough dark stripe in some specimens of C. vittatus ). The new species can be distinguished from C. flaveolus by the lower number of serrations on posterior margin of pectoral-fin spine (16-19 vs. 27-36) and on posterior margin of dorsal-fin spine (7-10 vs. 15-22); and by the presence of simple serrations on posterior margin of pectoral-fin spine (vs. presence of simple and bifid serrations). See additional diagnostic features in discussion.

Description. Morphometric data presented in Table 1. Head compressed with slightly convex dorsal profile; triangular in dorsal view. Snout slightly pointed. Head profile convex from snout to tip of posterior process of parieto-supraoccipital. Profile slightly convex along dorsal-fin base. Postdorsal-fin body profile concave to adipose-fin spine; concave from this point to caudal-fin base. Ventral profile of body nearly straight from isthmus to pectoral girdle; slightly convex from this point until pelvic girdle. Profile nearly straight from pelvic girdle to base of first anal-fin ray; slightly concave until caudal-fin base. Body roughly elliptical in cross section at pectoral girdle, gradually becoming more compressed toward caudal fin.

Eye rounded, located dorso-laterally on head; orbit delimited dorsally by frontal and sphenotic, ventrally by infraorbitals. Anterior and posterior nares close to each other, only separated by a flap of skin. Anterior naris tubular. Posterior naris close to anterodorsal margin of orbit, separated from it by a distance equal to diameter of naris. Mouth small, subterminal, width nearly equal to bony orbit diameter. Maxillary barbel short, not reaching anteroventral limit of gill opening. Outer mental barbel slightly longer than maxillary barbel. Inner mental barbel fleshy, base separated to its counterpart; insertion of barbell in middle of lower lip. Small rounded papillae covering entire surface of all barbels, upper and lower lips, and isthmus.

Mesethmoid short, posterior portion partially exposed and bearing minute odontodes. Nasal slender, curved laterally, anterior portion of inner margin laminar; mesial border contacting only frontal; with three nasal pores. Frontal elongated, narrow, width less than half entire length; anterior projection short, size smaller than nasal length; epiphyseal branch of supraorbital canal short, pore opening located mesially on frontals. Frontal fontanel large, oval; posterior tip slightly entering anterior margin of parieto-supraoccipital. Parieto-supraoccipital wide, posterior process long and contacting nuchal plate. Two laminar infraorbitals with minute odontodes; infraorbital 1 large, anterior portion with very large expansion; infraorbital 2 small, postero-ventral margin contacting supra-preopercle, dorsal tip slender, contacting sphenotic. Interopercle covered by thick layer of skin, somewhat triangular, anterior projection welldeveloped. Preopercle slender, elongated; minute odontodes sparse on external surface. Opercle elongated in shape, width nearly equal or smaller than half of its length; free margin smooth, without serrations and covered by small odontodes. Anteroventral portion of cleithrum exposed; posterolateral portion of scapulocoracoid exposed; minute odontodes sparse on exposed areas. Vertebral count 23(3); ribs 5(3), first pair conspicuously large.

Four branchiostegal rays decreasing in size posteriorly. Hypobranchial 2 somewhat triangular, tip ossified and directed towards anterior portion, posterior margin cartilaginous; ossified portion well developed, about twice size cartilaginous portion. Five ceratobranchials with expansions increasing posteriorly; ceratobranchial 1 with small process on anterior margin of mesial portion; ceratobranchial 3 notched on postero-lateral margin; ceratobranchial 5 toothed on postero-dorsal surface, 25-28(3) teeth aligned in one row. Four epibranchials with similar size; epibranchial 2 slightly larger than others, lacking small pointed process on laminar expansion of posterior margin; epibranchial 3 without uncinate process on laminar expansion of posterior margin. Two wide pharyngobranchials, pharyngobranchial 3 with large triangular process on posterior margin. Upper tooth plate oval; 30-37(3) teeth aligned in two rows on postero-ventral surface.

Dorsal-fin rays II,8*(20), II,9(1), posterior margin of dorsalfin spine with 7-10 serrations, disposed on distal half of the spine; nuchal plate exposed with minute odontodes; spinelet short; spine short, adpressed distal tip not surpassing base of last branched dorsal-fin ray, posterior margin with small odontodes. Pectoral-fin rays I,8; posterior margin of pectoral spine with 16-19 moderate developed serrations, disposed along entire length of posterior margin or absent close to the insertion of spine ( Fig. 2a ). Pelvic-fin rays i,5. Anal-fin rays i,6. Caudal-fin rays i,12,i, generally three dorsal and ventral procurrent rays, respectively; bilobed, with superior lobe slightly larger than inferior one; lobes with rounded distal border.

Three laterosensory canals on trunk; first ossicle tubular, second ossicle laminar and last lateral-line canal encased in third dorsolateral body plate. Body plates with minute odontodes scattered over exposed area, a conspicuous line of odontodes confined on posterior margins; dorsolateral body plates 23(3), 24*(18); ventrolateral body plates 20(2), 21*(19); dorsolateral body plates along dorsal-fin base 5(9), 6*(12); dorsolateral body plates between adipose and caudal fin 7(3), 8*(18); preadipose platelets 2(7), 3*(13), 4(1), adipose spine opposed to anal-fin insertion; small platelets covering base of caudal-fin rays; small platelets disposed dorsally and ventrally between junctions of lateral plates on posterior portion of caudal peduncle.Anterior margin of orbit with platelets, above posterior portion of lateral ethmoid and above the junction of frontal and lateral ethmoid. Ventral surface of the body without platelets.

Color in alcohol. Ground color of body brownish yellow, with top of the head dark brown. Tip of the snout generally with rounded black spots; scattered chromatophores not forming conspicuous spots in some specimens; few specimens lacking spots on snout. Diffuse dark stripe between corner of mouth and anterior margin of orbit. Posterior region of infraorbital 1 with a drop-shaped dark blotch. Black spots on dorsal portion of the head in some specimens. Region of nasal bone dark brown. Opercle with clear border; anterior portion dark brown. Upper portion of dorsolateral plates black or brownish blotched. Dorsal series of four black or brownish blotches, first on anterior portion of dorsal-fin base, second on posterior portion of dorsal-fin base, third on adipose-fin base and fourth on caudal-fin base. Midline of flank with four to six small rounded black or brownish blotches. Inferior portion of ventrolateral body plates generally black or brownish spotted posteriorly to pelvic fin. Dorsal and ventral portions of the posterior-most region of the caudal peduncle blackened. Ventral portion of caudal peduncle with a darkened region just posterior to anal fin. Dorsal and pectoral fins scarcely mottled. Tip of the spine and first branched dorsal-fin rays, including membranes, blackened. Pelvic fin generally hyaline. Adipose fin generally with hyaline membrane; with a darkened area on distal portion of membrane in some specimens. Anal fin generally black or brownish spotted; hyaline in some specimens. Middle portion of caudal- fin base with small black dot. Origin of each caudal-fin lobe with black blotch. Caudal fin with one to three irregular black bars.

Color in life. Similar to preserved specimens. Yellowish ground color of body slightly light and dark stripe between corner of mouth and anterior margin of orbit more evident than in preserved specimens.

Distribution. Corydoras lacrimostigmata is known from rio Ivaí basin, a tributary of the rio Paraná, in the State of Paraná, Brazil ( Fig. 3 ).

Etymology. From the Latim, the epithet lacrĭma, meaning tear, plus stigmata, meaning marks (plural of stigma), make allusion to the diffuse dark stripe between corner of mouth and anterior margin of orbit and the drop-shaped dark blotch on the posterior portion of infraorbital 1, which seem to be tears. A noun in apposition.

Figures

Fig. 1. Corydoras lacrimostigmata, holotype, MNRJ 40725, 31.8 mm SL, Brazil, Paraná, Cândido Abreu, rio Maria Flora, tributary to rio Ubazinho, rio Ivaí basin. Dorsal, lateral and ventral views.

Fig. 2. Pectoral-fin spine of Corydoras lacrimostigmata (a), NUP 14657, paratype, 30.9 mm SL, showing the serrations in posterior margin of the right spine (6.0 mm) and Corydoras flaveolus (b), LBP 14596, 33.5 mm SL, showing the serrations in posterior margin of the right spine (8.0 mm).Arrows indicate bifid serrations.

Fig. 3. Map showing geographic distribution of Corydoras lacrimostigmata. Red star represents the type locality, rio Maria Flora, the triangle represents rio Nestor and the square represents rio Barra Grande, upper rio Paraná basin, Paraná. Each symbol may represent more than one locality.