Parodon atratoensis, Londoño-Burbano & Román-Valencia & Taphorn, 2011
Londoño-Burbano, Alejandro, Román-Valencia, César & Taphorn, Donald C., 2011, Taxonomic review of Colombian Parodon (Characiformes: Parodontidae), with descriptions of three new species, Neotropical Ichthyology 9 (4), pp. 709-730 : 715-717
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Parodon atratoensis , new species
Fig. 4 View Fig
Parodon suborbitale .- Román-Valencia, 1990: 204 (listed as present in Atrato River basin).
Parodon suborbitalis .- Eigenmann, 1922: 109 (listed as present at Quibdó, Chocó department, and Truandó River, Atrato Basin). Maldonado et al., 2006:147 (listed as present in Atrato River basin, catalog numbers for Colombian collections)
Paratypes. Colombia, ICN 1584 View Materials , 1 View Materials , 98.4 mm SL, collected with holotype GoogleMaps . ICN 132 View Materials , 2 View Materials , 71.5-83.5 mm SL, Chocó , Quibdó, río Atrato drainage, 3 Aug 1959, G. Dahl . CAS 6781 View Materials , 1 View Materials , 93.6 mm SL, Chocó , río Sucio , río Atrato drainage, río Truando, a western tributary emptying into the Atrato near R. Sucio , 1 Jan 1913 - 31 Dec 1913, C. Wilson .
Diagnosis. Parodon atratoensis differs from all congeners in having just the first dorsal-fin ray unbranched (vs. two, except in P. magdalenensis ); two dorsal longitudinal stripes that end at adipose-fin origin (vs. ending at upper caudal-fin lobe or absent). It is distinguished from P. magdalenensis by a series of transverse dorsal bands ending at adipose fin (vs. ending at upper caudal-fin lobe or absent); in having the axillary scale 2-3 normal scales in length (vs. usually one, rarely two scales in length; except in P. buckleyi ). It also differs in the number of cusps on the premaxillary teeth (12-13 vs. 15-19 in P. carrikeri ; 7-12 in P. bifasciatus ; 9-12 in P. pongoensis ). It can be differentiated from P. guyanensis by the number of teeth on the premaxilla (4 vs. 5) and from P. pongoensis and P. moreirai by the presence of a lateral band with projections above and below (vs. absence of projections in such band) and the number of scales in the lateral line (37-38 vs. 40-42 in P. moreirai ). From P. suborbitalis it is distinguished by the number of cusps on premaxillary teeth (12-13 vs. 15-17); number of branched pectoral-fin rays (12-13 vs. 14-17); preanal scales (23-24 vs. 24-27); two light dorsal stripes uniting at adipose fin (vs. stripes ending at upper caudal-fin lobe) and transverse dorsal blotches ending at adipose fin (vs. dorsal blotches ending at base of upper caudal-fin lobe). From P. hilarii it differs by the absence of spots above lateral stripe (vs. present); the number of preanal scales (23-24 vs. 24-28). It differs from P. nasus by the presence of elongated projections of the lateral stripe (vs. rounded projections) and the number of cusps on premaxillary teeth (12-13 vs. 13-15).
Description. Morphometric and meristic data given in Tables 1 and 2, respectively. Body stout. Dorsal head profile straight from snout to tip of supraoccipital process. Ventral head profile straight from snout to isthmus; isthmus located at vertical through tip of supraoccipital process. Dorsal trunk profile convex from tip of supraoccipital process to dorsal-fin origin, straight from there to upper caudal-fin lobe. Branchial membranes united to each other but free from isthmus. Eyes lateral; nares at height of eye, two orifices separated by projecting skin membrane, anterior orifice larger. Mouth ventral, upper lip absent. Ventral trunk profile rounded from isthmus to anal-fin origin, then concave to lower caudal-fin lobe. Caudal peduncle compressed.
Premaxillary hemiseries with four teeth in straight line, each tooth with straight ventral margin and 12-13 small cusps; these teeth fit into space in lower jaw. Maxilla with one or two multicuspid teeth, smaller than those on premaxilla and often half buried in soft tissue. Lower jaw with one to three lateral, outwardly-curved teeth, not visible when jaw closed.
Pectoral fin inserted at vertical through tip of supraoccipital process, or one scale posterior; fins short, their tips not reaching pelvic-fin insertions; fifth branched ray longest. Pelvic fin always reaching genital pore but not anal-fin origin even in adults; inserted at vertical through middle of dorsalfin base. Dorsal fin truncate, with second to fourth rays longer than others, its origin at or slightly posterior to vertical through point midway between pectoral and pelvic fin insertions. Anal fin not reaching lower caudal-fin lobe by one or two scales, its origin at vertical through point one or two scales anterior to adipose-fin origin.Adipose fin not reaching upper caudal-fin lobe, its origin at vertical through middle of anal-fin base. Caudal fin with two lobes of equal length, covered proximally with scales for 1/3 length. Lateral line with 37-38 pored scales, complete, extending on to proximal third of caudal fin. Predorsal and ventral regions regularly scaled. Axillary scale present, two to three scales in length.
Color in alcohol. Snout and head usually uniformly brown, not lighter below eye (one 98.4 mm SL individual with lighter colored infraorbitals two and three). Dorsum of body with series of light brown transverse blotches that begin one scale posterior to tip of supraoccipital process and continue to adipose-fin base, delimited on both sides of body by two light brown stripes of at least two scales in width, that begin on snout or behind supraoccipital and extend posteriorly to unite at adipose fin. Body base color dark yellow. Dark lateral stripe zigzag with 13-15 very short points, most conspicuous in individuals smaller than 85 mm SL; no additional blotches or bands observed above zigzag stripe. Lateral stripe continued onto middle caudal-fin rays.
Pectoral fin with light brown blotch usually distal in position but sometimes larger, extending towards base of fin, all rays with very disperse brown chromatophores, giving fin very dark general appearance. Pelvic fin with very few chromatophores not forming blotches or bands. Anal and adipose fins hyaline. Dorsal fin with first four rays covered with dark brown chromatophores not forming blotches or bands. Caudal fin with middle rays dark brown to tips. Ventral part of body same as base color of sides, without spots or chromatophores.
Sexual dimorphism. Few breeding tubercles observed in males, usually only on anterior part of snout. In one male, 107.5 mm SL tubercles present from snout to supraoccipital.
Distribution. Río Atrato basin, Colombia ( Fig. 2 View Fig ).
Etymology. This species, Parodon atratoensis , is named in reference to its type-locality, the Atrato River, northwest Colombia.
Comments. Román-Valencia (1990) reported Parodon suborbitalis from the Atrato River drainage. In this study, we re-examined two specimens he used (ICN 1584) and confirm that they are the new species described here as P. atratoensis . They are distinguished from P. suborbitalis by the following characters: number of cusps on premaxillary teeth: 12-13 (vs. 15-17); number of branched pectoral-fin rays 12-13 (vs. 14- 16); one simple dorsal-fin ray (vs. two); preanal scales 23-24 (vs. 24-27); spots above lateral stripe absent (vs. present); two light dorsal stripes uniting at adipose fin (vs. stripes ending at upper caudal-fin lobe) and transverse dorsal blotches ending at adipose fin (vs. dorsal blotches ending at base of upper caudal-fin lobe). Parodon suborbitalis is found in the Lake Maracaibo and is absent from Pacific Colombian coastal drainages. Reports of P. suborbitalis by Eigenmann (1922) and Maldonado et al. (2005; 2006) from the Atrato were also based on specimens of P. atratoensis .
Parodon atratoensis shows little overlap in meristic characters with P. suborbitalis , so even though our sample size is small have found supporting evidence for us to diagnose those specimens as a new species, the only valid parodontid species known to date from the Atrato River drainage.
Instituto de Ciencias Naturales, Museo de Historia Natural
Departamento de Geologia, Universidad de Chile
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