Imparfinis timana, Ortega-Lara & Milani & DoNascimiento & Villa-Navarro & Maldonado-Ocampo, 2011

Ortega-Lara, Armando, Milani, Nadia, DoNascimiento, Carlos, Villa-Navarro, Francisco & Maldonado-Ocampo, Javier Alejandro, 2011, Two new trans-Andean species of Imparfinis Eigenmann & Norris, 1900 (Siluriformes: Heptapteridae) from Colombia, Neotropical Ichthyology 9 (4), pp. 777-793 : 778-782

Imparfinis timana , new species

Fig. 1

Holotype. IAvH-P 10696, 74.2 mm SL, Colombia, Departamento del Huila, Municipio Palestina, río Guarapas , in the mouth of quebrada La Quebradona , small tributary of upper río Magdalena basin, 01º45’49”N 76º05’05”W, 1350 m asl, 17Aug 2005, J.A. Maldonado- Ocampo, J. Bogotá-Gregory, F. Villa-Navarro & A. Ortega-Lara.

Paratypes. Colombia: río Magdalena basin: Departamento del Huila: CZUT-IC 2389 , 4 , 29.6-46.8 mm SL, collected with the holotype. IAvH-P 7062, 5, 51.0-72.0 mm SL, collected with the holotype. IAvH-P 7061, 9, 54.7-76.6 mm SL (2 CS, 62.7-76.2 mm SL), IMCN 1203 , 1 CS, 62.5 mm SL, MBUCV-V-33735, 3, 47.9-68.8 mm SL (1 CS, 47.9 mm SL), Municipio Palestina, quebrada La Quebradona, in the mouth of río Guarapas, 01º45’51”N 76º05’21”W, 1350 m asl, same date and collectors as the holotype. IAvH-P 7067, 36, 42.4-57.2 mm SL (1 CS, 42.4 mm SL), IMCN 2003 , 2 , 51.6-60.7 mm SL, Municipio Pitalito, río Guarapas , Tasajera, 01º51’25”N 76º02’34.2”W, 1320 m asl, same date and collectors as the holotype .

Diagnosis. This species is distinguished from all trans-Andean species of the genus ( I. lineatus , I. nemacheir , I. spurrellii , and I. usmai ) by its longer adipose-fin (24.6-31.3% in SL vs. 17.2-18.6% in I. lineatus ; 19.0-21.8% in I. nemacheir ; 21.1- 22.9% in I. spurrellii ; 21.1-27.0% in I. usmai ) and longer analfin base (12.4-15.5% in SL vs. 10.9-11.7% in I. lineatus ; 9.6- 13.1% in I. nemacheir ; 11.5-12.0 % in I. spurrellii ; 10.8-14.5% in I. usmai ). Imparfinis timana can be differentiated from all trans-Andean species, except I. lineatus , by having 5-6 gill rakers on the first ceratobranchial (vs. 7-8 in I. nemacheir and I. usmai ; 10-11 in I. spurrellii ); 42-43 vertebrae (vs. 38-40 in I. nemacheir ; 45 in I. spurrellii ; 39-40 in I. usmai ) and greater caudal peduncle depth (7.1-8.7% in SL vs. 5.3-6.9% in I. nemacheir ; 7.0-7.2% in I. spurrellii ; 5.6-7.8% in I. usmai ). Imparfinis timana is distinguished from I. nemacheir and I. spurrellii , by a greater interorbital width (29.4-38.1 % in HL vs. 28.2-30.5% in I. nemacheir ; 23.6-24.3% in I. spurrellii ). Imparfinis timana is further recognized from I. lineatus by its shorter predorsal length (30.7-36.9% in SL vs. 36.0-37.9%); by the longer maxillary barbel (exceeding end of pectoral-fin, maxillary barbel length: 32.3-45.0% in SL vs. extending to half length of pectoral fin, 24.0-32.6%), and by the upper caudal fin lobe longer than lower lobe (lower caudal fin lobe length/ upper caudal fin lobe length: 0.73-0.93 times) vs. both lobes approximately symmetrical (0.93-0.96 times). Imparfinis timana also differs from I. nemacheir by having the first ray of dorsal and pectoral fins shorter than the second ray of the respective fin (vs. longer and extended as a filament projected beyond the margin in both fins); shorter maxillary barbels (not surpassing the pelvic-fin base vs. surpassing the pelvic-fin base) and shorter caudal-fin lobes (upper caudal-fin lobe length: 21.9-28.0% in SL vs. 38.2-52.1%; lower caudal-fin lobe length: 18.4-23.8% in SL vs. 28.6-32.3%). Imparfinis timana is readily distinguished from all cis-Andean congeners as follows: from I. borodini by having a deeper head (1.6-1.9 times in HL vs. ca. 2.2 times, obtained from holotype picture), longer maxillary barbels (reaching pelvic fin vs. slightly beyond pectoral-fin base), fewer vertebrae (42-43 vs. 49-54), insertion of first dorsal-fin pterygiophore posterior to neural spine of vertebra 7 (vs. vertebra 12-13), pelvic-fin origin at or slightly posterior to mid-distance of dorsal-fin base (vs. at vertical or slightly anterior to dorsal-fin origin), shorter adipose fin (3.19- 4.06 times in SL vs. 2.67 times), fewer total anal-fin rays (11-13 vs. 14-15), insertion of first anal-fin pterygiophore posterior to hemal spine of vertebra 23-24 (vs. vertebra 30-31), caudal fin deeply forked (vs. caudal fin obliquely truncated with upper end longer and prolonged in a pointed tip), and more branched caudal-fin rays (7+8 vs. 6+6); from I. cochabambae (Fowler, 1940) by having fewer gill rakers on first gill arch (8 vs. 15), more vertebrae (42-43 vs. 41), pectoral-fin distal tip not reaching pelvic-fin origin (vs. surpassing pelvic-fin origin), longer adipose fin (3.19-4.06 times in SL vs. 4.12 times), and lower caudal-fin lobe rounded (vs. pointed); from I. guttatus by having fewer gill rakers on first gill arch (8 vs. 14), longer adipose fin (3.19-4.06 times vs. ca. 5.65 times, obtained from holotype picture), both caudal-fin lobes similarly pigmented (vs. lower caudal-fin lobe darker), and hypural 5 partially fused at base with 3+4 (vs. free); from I. hasemani by having longer maxillary barbels (reaching pelvic-fin base vs. not surpassing pectoral-fin distal margin), more vertebrae (42-43 vs. 40), fewer pleural ribs (9 vs. 10) and longer adipose-fin (24.6-31.3% in SL vs. 20.9-21.6%, obtained from measurements in Steindachner, 1915); from I. hollandi by having longer maxillary barbels (reaching pelvic fin vs. not surpassing pectoral-fin distal margin), fewer gill rakers on first gill arch (8 vs. 9), fewer vertebrae (42-43 vs. 52-53), fewer pleural ribs (9 vs. 11), insertion of first dorsal-fin pterygiophore posterior to neural spine of vertebra 7 (vs. vertebra 12), pelvic-fin origin at or slightly posterior to mid-distance of dorsal-fin base (vs. at vertical or slightly posterior to dorsal-fin origin), adipose fin free from caudal fin (vs. continuous), fewer total anal-fin rays (11-13 vs. 14-15), insertion of first anal-fin pterygiophore posterior to hemal spine of vertebra 23-24 (vs. vertebra 29-30), caudal fin deeply forked (vs. obliquely truncated, with upper end prolonged), and more branched caudal-fin rays (7+8 vs. 6+5-6); from I. longicauda by having a longer head (4.22-5.1 times in SL vs. 6 times or more), and insertion of first dorsalfin pterygiophore posterior to neural spine of vertebra 7 (vs. vertebra 8); from I. microps Eigenmann & Fisher, 1916 by having longer maxillary barbels (reaching pelvic-fin base vs. not extending beyond posterior margin of branchiostegal membrane), fewer branchiostegal rays (7-8 vs. 9), more gill rakers on first gill arch (8 vs. 4-5), fewer vertebrae (42-43 vs. 46-47), more pleural ribs (9 vs. 8), more branched pectoral-fin rays (8-9 vs. 7), more posterior pelvic-fin origin (at or slightly posterior to mid-distance of dorsal-fin base vs. anterior to dorsal-fin origin), insertion of first dorsal-fin pterygiophore posterior to neural spine of vertebra 7 (vs. vertebra 15), fewer branched anal-fin rays (7-8 vs. 9), anal-fin origin at vertical through adipose-fin origin (vs. anterior), insertion of first analfin pterygiophore posterior to hemal spine of vertebra 23-24 (vs. vertebra 26), and more branched caudal-fin rays (7+8 vs. 6+6); from I. minutus by having longer maxillary barbels (reaching pelvic-fin base vs. not surpassing distal tip of adpressed pectoral fin), more vertebrae (42-43 vs. 41), more pleural ribs (9 vs. 8), insertion of first dorsal-fin pterygiophore posterior to neural spine of vertebra 7 (vs. vertebra 8-9), and longer adipose fin (3.19-4.06 times in SL vs. 4.7 times); from I. mirini by having longer maxillary barbels (reaching pelvic-fin base vs. scarcely beyond distal tip of adpressed pectoral fin), more vertebrae (42-43 vs. 38-40), adipose-fin posterior end extending more posteriorly than distal margin of adpressed anal fin (vs. approximately at same level), and upper caudalfin lobe longer than lower lobe (vs. both caudal-fin lobes equal in length); from I. mishky by having fewer gill rakers on first gill arch (8 vs. 9), fewer branched rays on lower lobe of caudalfin (8 vs. 9), longer and deeper caudal peduncle (19.3-25.6% in SL and 7.1-8.7%, respectively vs. 17.7-20.1% and 6.4-7.8%), and greater interorbital width (29.4-38.1% in SL vs. 18.5-23.1%); from I. peruanus by having a shorter predorsal distance (2.71- 3.25 times in SL vs. 2.6 times), insertion of first dorsal-fin pterygiophore posterior to neural spine of vertebra 7 (vs. vertebra 9), adipose-fin origin at vertical through anal-fin origin (vs. anterior), insertion of first anal-fin pterygiophore posterior to hemal spine of vertebra 23-24 (vs. vertebra 25), PH fused with 1+2 (vs. PH free); from I. pijpersi by having longer maxillary barbels (reaching pelvic-fin base vs. not surpassing distal tip of adpressed pectoral fin), longer caudal peduncle (19.3-25.6% in SL vs. 16.1%), shorter caudal peduncle depth (7.1-8.7% in SL vs. 11.0%), and longer adipose fin (24.6-31.3% in SL vs. 13.1%); from I. piperatus by having longer maxillary barbels (reaching pelvic-fin base vs. reaching distal tip of adpressed pectoral fin), more vertebrae (42-43 vs. 37), more pleural ribs (9 vs. 8), and insertion of first anal-fin pterygiophore posterior to hemal spine of vertebra 23-24 (vs. vertebra 20); from I. pristos by having a larger size (maximum SL: 76.7 mm vs. 38 mm, value from Bockmann & Guazelli, 2003), shorter head (4.2-5.1 times in SL vs. 3.4-3.7), longer maxillary barbels (reaching pelvic-fin base vs. not surpassing distal tip of adpressed pectoral fin), more gill rakers on first gill arch (8 vs. 4-6), more vertebrae (42- 43 vs. 33-35), more pleural ribs (9 vs. 6), insertion of first dorsalfin pterygiophore posterior to neural spine of vertebra 7 (vs. vertebra 6), longer adipose fin (3.19-4.06 times in SL vs. 5.0- 5.6 times), more branched anal-fin rays (7-8 vs. 5-6), insertion of first anal-fin pterygiophore posterior to hemal spine of vertebra 23-24 (vs. vertebra 17-18), upper caudal-fin lobe longer than lower lobe (vs. both caudal-fin lobes equal in length), and more branched rays on caudal fin (7+8 vs. 6+7); from I. pseudonemacheir Mees & Cala, 1989 by having a larger size (maximum SL: 76.7 mm vs. 48.1 mm), shorter maxillary barbels (reaching pelvic-fin base vs. reaching posterior end of analfin base), fewer gill rakers on first gill arch (8 vs. 11-14), more vertebrae (42-43 vs. 35-36), first ray of dorsal and pectoral fins shorter than the second ray of the respective fin (vs. longer and extended as a filament projected beyond the margin in both fins), pectoral-fin distal end not reaching pelvic-fin origin (vs. reaching or surpassing pelvic-fin base), longer adipose fin (3.19-4.06 times in SL vs. 4.5-5.0 times), anal-fin origin at the same level of adipose-fin origin (vs. posterior), distal margin of adpressed anal fin anterior to adipose-fin posterior end (vs. posterior), upper caudal-fin lobe longer than lower lobe (vs. both caudal-fin lobes equal in length), and sides of body without distinct markings (vs. four irregular dark patches); from I. schubarti by having longer maxillary barbels (reaching pelvic-fin base vs. reaching or scarcely beyond distal tip of adpressed pectoral fin), fewer gill rakers on first gill arch (8 vs. 11-16), fewer vertebrae (42-43 vs. 39-40), longer adipose-fin base (24.6-31.3% in SL vs. 18.7-22.6%), and shorter preanal length (62.2-70.6% in SL vs. 71.0-74.7%); and from I. stictonotus by having shorter maxillary barbels (reaching pelvic-fin base vs. extending to first half of adipose-fin base), more vertebrae (42-43 vs. 34-38), more pleural ribs (9 vs. 6-8), first ray of dorsal and pectoral fins shorter than the second ray of the respective fin (vs. longer and extended as a filament projected beyond the margin in both fins), pectoral-fin distal end not reaching pelvic-fin origin (vs. reaching or surpassing pelvic-fin base), more branched anal-fin rays (7-8 vs. 6), both caudal-fin lobes similarly pigmented (vs. lower lobe darker than upper lobe), and sides of body without distinct markings (vs. four irregular dark patches).

Description. Morphometric data given in Table 1 . Small heptapterid catfish (largest specimen 76.7 mm SL), with elongated body, triangular in cross-section at dorsal-fin origin, progressively more laterally compressed to tail region. Dorsal profile slightly convex from snout tip to dorsal-fin origin, slightly concave just posterior to dorsal-fin base to adipose-fin origin, straight and descending along adiposefin base, then ascending along caudal peduncle. Ventral profile of head straight, slightly convex along abdomen, then straight to anal-fin origin and slightly descending along caudal peduncle.

Head conical and depressed, dorsally covered by thin skin. Snout short and broadly rounded. Mouth subterminal. Premaxillary teeth conical and pointed arranged in rectangular band with 4-5 irregular rows. Dentary with four irregular rows of teeth. Barbels dorsoventrally flattened. Maxillary barbels generally extending to pelvic-fin base, but reaching anal fin in some juvenile specimens. Anterior portion of maxillary barbel in shallow groove. Bases of outer and inner mental barbels aligned. Outer mental barbels surpass pectoral-fin base. Inner mental barbels reach pectoral-fin origin. Eye dorsolateral in position. Orbital margin not free, but delimited by shallow groove, more conspicuous along dorsal rim. Anterior naris tubular. Posterior naris rounded, slightly closer to anterior ocular margin than to anterior naris, bordered by low fleshy margin, with notch in posterior border. Nares disposed in trapezoidal arrangement.Anterior internarial width slightly shorter (mean % in HL: 15.2) than posterior internarial width (mean % in HL: 19.4). Branchiostegal membrane free, supported by 7-8 rays and joined to isthmus only at anteriormost point. Gill rakers on first gill arch eight, 5-6 arranged on anterior margin of ceratobranchial, one on cartilage between ceratobranchial and epibranchial, and 1-2 on epibranchial.

Lateral line canal complete, extending to basal portion of interradial membrane of middle caudal-fin rays. Supraorbital pore S1 medially adjacent to anterior naris. S2+I2 midway between anterior and posterior nares, at end of posteriorly directed membranous tubule originating from commissure connecting supraorbital and infraorbital canals, closer to supraorbital canal. S3 posteriorly adjacent to posterior naris and S4 located approximately at mid-distance between posterior naris and eye margin and at level of medial border of posterior naris. Both S3 and S4 originating from anterior and posterior ends of bifurcated lateral membranous branch with T-shape. S7 located dorsomedial and posterior to eye, originating from short membranous tubule running posteriorly. S8 (corresponding to parietal branch), posteromedial to eye. Parietal branch running posteriorly on frontal bone, and ending close to articular suture with parietosupraoccipital bone. Infraorbital pore I1 laterally adjacent to anterior naris, just between naris and maxillary barbel base. I3 posterior to maxillary barbel base. I4 at vertical through anterior eye margin. I5 at vertical through posterior eye margin. I6 posterior to eye at end of short ventroposterior membranous tubule. Preoperculomandibular canal with 11 pores. Dentary with seven pores. Submental pores (PM1) paired and last mandibular pore (PM7) at level of articulation between anguloarticular and quadrate bones. Preopercle with three pores. Anterior pore (PM8) originating between subpreopercle and preopercle. Middle pore (PM9) originating from membranous tubule passing above interopercle and posterior pore (PM10) from membranous tubule passing above ventral portion of opercle. Last preopercular pore (PO1+PM11) at end of membranous branch dorsal to dorsal edge of opercle, close to articulation between opercle and hyomandibula. PO2 corresponding to pterotic branch, located dorsal to dorsoposterior corner of opercular margin. Axillary branch (LL1) ventral, running posterior to extrascapular. Accessory branch (PO3) dorsal to lateral line canal, ending approximately at axilar pore level.

Precaudal vertebrae 12 and caudal vertebrae 30-31, totaling 42-43 vertebrae. First hemal spine on vertebra 16-17. Pleural ribs nine.Anus approximately at mid-length of pelvic fin, closer to pelvic-fin base than anal-fin origin. Urogenital papilla separated from anus by distance approximately equivalent to length of papilla.

Pectoral fin i,8-9. Basal portion of simple ray ossified, distal portion soft and segmented. First and second branched rays longest. Distal margin of pectoral fin straight. Pelvic fin i,5. First pelvic-fin ray thick and shortest, second and third branched rays longest. Pelvic-fin origin at or slightly posterior to mid-distance of dorsal-fin base. Dorsal fin lacking spinelet (i.e. first lepidotrichium), with one simple (second lepidotrichium), and six branched rays. Dorsal fin triangular, second ray longest. Supporting fin elements represented by seven proximal and six distal radials. Last two branched rays articulating separately with last two pterygiophores. First proximal radial inserted posterior to neural spine of vertebra 7 and last proximal radial inserted anterior to neural spine of vertebra 13.Adipose fin low, its maximum height at mid-length, and longer than anal fin, with free posterior lobe. Adipose-fin origin at vertical through anal-fin origin. Anal fin with 2-3 procurrent rays, associated with first proximal radial, two simple rays and 7-8 branched rays. Anal-fin distal margin rounded. Anal fin supported by 10 proximal and nine distal radials. First proximal radial posterior to hemal spine of vertebra 23-24 and last proximal radial anterior to hemal spine of vertebra 30-31. Caudal fin deeply forked with i,7+8,i principal rays. Upper caudal-fin lobe pointed and longer than lower lobe. Lower caudal-fin lobe rounded. Dorsal procurrent caudal-fin rays 13-16, located posterior to vertebrae PU 5 -PU 6. Last 2-3 rays segmented. Ventral procurrent caudal-fin rays 13-15, located posterior to vertebrae PU 6 -PU 7. Last 2-3 rays segmented. Caudal skeleton PH, 1+2, 3+4 partially fused at base with 5. Long epural present.

Coloration in alcohol. Body brownish on dorsal and lateral surfaces, and ventral region cream. Conspicuous, dark midlateral stripe, extending from posterior margin of opercle to caudal-fin origin. Dorsal surface of maxillary barbel pigmented. Outer mental barbel scarcely pigmented at basal portion. Inner mental barbel light-colored. Parieto-supraoccipital region densely pigmented. Dark blotch on opercle. Four dark saddles in dorsum, first saddle crossing predorsal region, second saddle just in front of dorsal-fin origin, third saddle on posterior half of dorsal-fin base, and last saddle between dorsal and adipose fins. Rays of pectoral, dorsal and caudal fins darkly pigmented. Interradial membranes hyaline. Distal portion of pectoral fin light-colored. First pelvic-fin rays with chromatophores scattered. Anal and adipose fins light-colored.

Distribution. This species is only known from the type locality at the río Guarapas, a small tributary of the upper río Magdalena basin ( Fig. 2 ).

Etymology. Timana is used as a noun in apposition and refers to the indigenous people inhabiting the west flank of the eastern cordillera, in the Colombian Andes, from San Agustin to Pitalito (Departamento del Huila).

Figures

Fig. 1. Imparfinis timana, holotype, IAvH-P 10696, 74.2 mm SL, Colombia, Huila, Palestina, río Guarapas, in the mouth of quebrada La Quebradona, upper río Magdalena basin, 01º45’49”N 76º05’05”W. Scale bar = 1 cm.

Fig. 2. Map of midwestern region of Colombia showing geographic distribution of Imparfinis timana (circle, star: holotype locality) and I. usmai (squares, diamond: holotype locality). Some symbols represent more than one lot and/or locality.