Sternarchorhynchus axelrodi, Santana & Vari, 2010

Santana, Carlos David De & Vari, Richard P., 2010, Electric fishes of the genus Sternarchorhynchus (Teleostei, Ostariophysi, Gymnotiformes); phylogenetic and revisionary studies, Zoological Journal of the Linnean Society 159 (1), pp. 223-371 : 275

publication ID

https://doi.org/ 10.1111/j.1096-3642.2009.00588.x

persistent identifier

https://treatment.plazi.org/id/03E687C2-284F-FFD8-7C87-FD4AA2DF6158

treatment provided by

Valdenar

scientific name

Sternarchorhynchus axelrodi
status

sp. nov.

STERNARCHORHYNCHUS AXELRODI View in CoL SP. NOV.

( FIGS 26–28 View Figure 26 View Figure 27 View Figure 28 ; TABLE 4)

Sternarchorhynchus cf. mormyrus View in CoL , Campos-da-Paz, 2000: 533 [ Brazil, Rio Tocantins; as probable undescribed species].

Sternarchorhynchus mormyrus View in CoL , not of Steindachner, dos Santos et al., 2004: 103, unnumbered figure [ Brazil, lower Rio Tocantins; food habits].

Diagnosis: Sternarchorhynchus axelrodi is distinguished from all congeners by the following combination of characters: a short gape that terminates posteriorly at, or slightly short of, the vertical through the anterior nares, the absence of scales along the mid-dorsal region of the body as far posteriorly as the origin of the electroreceptive filament, and the possession of 200–217 anal-fin rays.

Description: Morphometric data for examined specimens in Table 4.

Lateral line extending posteriorly to base of caudal fin, but absent on fin. Snout elongate, compressed and curved ventrally, and with sexual dimorphism in overall form across examined specimens of large body sizes. Snout more anteroventrally aligned in mature females than in mature males of comparable sizes as evidenced by specimens of each sex with mature gonads. Sexual dimorphism in form of lower jaw and associated dentition found in many congeners not apparent in examined samples. Mouth terminal, rictus situated anterior of vertical through anterior naris. Anus and urogenital papilla located ventral to head, with openings situated anterior to vertical through anterior margin of eye (in specimens of 433– 510 mm SL). Combined opening for anus and urogenital papilla distinctly elongate longitudinally and bordered laterally by raised fleshy ridges.

Premaxilla with six to ten teeth apparent in whole specimens (N = 4). Dentary with one tooth row consisting of nine to 15 curved conical teeth in whole specimens (N = 4), with second row of apparent replacement teeth located internal to functional row.

Branchiostegal rays five; with first to third rays apparently narrow and elongate in radiographs, and with fourth and fifth rays clearly very large and broad. Precaudal vertebrae 18–19 (15 anterior; three to four transitional; N = 10).

Pectoral-fin rays ii + 13–17 [ii + 16] (N = 10). Analfin origin located anterior to opercle. Anterior unbranched anal-fin rays 22–34 [33] (N = 5). Total anal-fin rays 200–217 [205] (N = 10). Scales above lateral line at midbody nine to 11 [11] (N = 10). Scales absent along much of mid-dorsal line in region anterior to origin of midsaggital electroreceptive filament. Areas lacking scales sometimes separated by regions covered by mid-dorsal scales, but with position and extent of regions lacking scales variable across examined specimens. Origin of midsaggital electroreceptive filament located approximately at 65% of TL.

Kingdom

Animalia

Phylum

Chordata

Class

Actinopterygii

Order

Gymnotiformes

Family

Apteronotidae

Genus

Sternarchorhynchus

Loc

Sternarchorhynchus axelrodi

Santana, Carlos David De & Vari, Richard P. 2010
2010
Loc

Sternarchorhynchus mormyrus

dos Santos GM & de Merona B & Juras AA & Jegu M 2004: 103
2004
Loc

Sternarchorhynchus cf. mormyrus

Campos-da-Paz R 2000: 533
2000
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