Brachyhypopomus jureiae Triques & Khamis, 2003

Crampton, William G. R., Santana, Carlos D. de, Waddell, Joseph C. & Lovejoy, Nathan R., 2016, A taxonomic revision of the Neotropical electric fish genus Brachyhypopomus (Ostariophysi: Gymnotiformes: Hypopomidae), with descriptions of 15 new species, Neotropical Ichthyology (e 150146) 14 (4), pp. 639-790 : 738-739

Brachyhypopomus jureiae Triques & Khamis, 2003

( Fig. 33 ; Tables 2-5, 15)

Brachyhypopomus jureiae Triques & Khamis, 2003: 62 , fig. 1, color photograph of paratype (original description, type locality – Brazil, São Paulo, rio Una do Prelado, Juréia Ecological Station). - Oyakawa et al., 2006: 74, color photograph of live individual ( Brazil, São Paulo, catalog of fishes from Atlantic forest streams). - Menezes et al., 2007: 319 (reproduction of photograph from Oyakawa et al., 2006). - Crampton & Albert, 2006: 672, fig. 23.8, position in phylogenetic tree; 681, notes on EODs (gymnotiform species and EOD diversity). -Crampton, 2011: 176, table 10.2, species list; 179, figs. 10.2- 10.3, phylogeny, geographical and ecological distributions (gymnotiform biology). - Crampton et al., 2016: 1-66, table 1, 3-4, figs. 1-7, 18-20 (phylogeny, biogeography and ecology of Brachyhypopomus ).

Diagnosis. Brachyhypopomus jureiae is diagnosed from congeners by the following combination of characters: bilateral columns of electrocytes at the anal-fin terminus 4, vs. 6 in B. bennetti and vs. 3 in all other congeners except B. belindae , B. diazi , B. janeiroensis , B. occidentalis (except some populations in Colombia and Venezuela, see redescription of B. occidentalis ), and B. palenque ; precaudal vertebrae 20, vs. 16-19 in B. diazi and vs. 24- 26 in B. belindae ; snout to pectoral-fin base 12.3-15.7% LEA, vs. 10.7-12.3% in B. janeiroensis ; pectoral-fin rays 14-16, vs. 17-21 in B. palenque . Brachyhypopomus jureiae exhibits similar pigmentation and overlapping meristic counts and morphometric proportions with B. occidentalis but can be distinguished by absence of the lateral ethmoid absent, vs. presence (Mago-Leccia, 1978: 58, fig. 11) in B. occidentalis .

Description. Head and body shape, and pigmentation illustrated in Fig. 33 . Meristic and morphometric data for examined specimens presented in Tables 2-5 and 15. Body moderate in depth. Head moderate in length and shallow to moderate in depth. Dorsal profile of head approximately straight from occiput to snout, ventral profile of head approximately straight to slightly concave between operculum and snout, snout rounded. Eye moderate in size. Upper jaw with moderate sigmoidal angle between premaxillary and maxillary portions in lateral view. No accessory electric organ over operculum. Pectoral fin moderate in width, pectoral-fin rays 14-16 (mode 16). Precaudal vertebrae 20, with 1-2 (mode 2) transitional vertebrae. Anal-fin origin slightly (<0.25 HL distance) posterior to, or near, tip of pectoral fin. Anal-fin rays 188-220 rays (197-220, median 205 in specimens we examined). Dorsal rami of recurrent branch of anterior lateral line nerve visible. Middorsal region of body scaled. Rows of scales above lateral line 6-7 (mode 6). Lateral line continuous. Many specimens with complete absence of groove-like depigmented epidermal canals. Some specimens with very sparse depigmented canals bordered by dark pigment, forming parallel wavy scratch-like marks either side of and near (1-2 scales distance from) lateral line in posterior half of body only (mostly dorsal to lateral line), and some single meandering canals in upper dorsum. Four bilateral horizontal columns of electrocytes at anal-fin terminus, and at a mid-point between anal-fin terminus and tip of caudal filament in immature, mature female, and mature male specimens. Caudal filament moderate to long in length.

Coloration. ( Fig. 33 ). Background pale to dark brown, much darker dorsal to lateral line. Dorsal region without prominent depigmented pale stripe extending along midline from occipital region to base of caudal filament. Dorsal surface speckled with dark pigment and irregular dark flecks or patches over background. Vertical stripes and saddles absent on flank. Dorsal and ventral flank with light, even scattering of chromatophores and with irregular dark brown or charcoal spots. Caudal filament darker dorsally and with irregular dark patches. Head with very pale background color ventrally, darker dorsally. Eye without prominent suborbital patch, or stripe, of chromatophores/subcutaneous pigmentation. Pectoral and anal-fin membranes hyaline. Pectoral and anal-fin rays hyaline with light scattering of brown chromatophores. Color in live individuals similar to preserved specimens, with opercular region usually rosy due to underlying gills.

Size. Moderate adult size, largest specimen examined 292 mm TL, 194 mm LEA (n = 14). Largest male specimen examined 170 mm TL, 125 mm LEA (n = 1). Largest female specimen examined 169 mm TL, 116 mm LEA (n = 4).

Sexual dimorphism. No known secondary sexual dimorphism.

Geographic distribution. Brazil ( Fig. 23 ). Known only from the rio Una do Prelado and rio Ribeira de Iguape, coastal drainages in southeast São Paulo state.

Ecological notes. Brachyhypopomus jureiae is known from small Atlantic forest and coastal lowland streams. Triques & Khamis (2003) provide some notes on the ecology of the type locality: “specimens were collected in the rio do Descalvado, a blackwater river of muddy bottom with surface partially covered by water-hyacinth ( Eichhornia sp. ); grasses are occasionally present on the margins. Water pH 6.0.” One of us (WGRC) collected B. jureiae from small very slow-flowing blackwater streams of the rio Ribeira de Iguape drainage in July 2006 and July 2008. The streams traversed forest fragments and pastureland, were 0.5- 2 m in width, up to 0.5 m deep, and had clay or sandy beds. All specimens were collected from submerged leaf litter or marginal vegetation. The following water parameters were recorded: conductivity 55-62 µScm-1, dissolved oxygen 2.5-3.0 mgl-1, temperature 15-23°C, pH 6.4. Reproductive biology is unknown. Stomach contents of specimens from the rio Ribeira de Iguape drainage comprise aquatic insect larvae and other small aquatic invertebrates (WGRC unpublished data).

Co-occurring congeners: None.

Local names. Brazil: tuvira.

Material examined. 14 specimens. Brazil. São Paulo. DZUFMG 010, 1 (holotype), 292 mm TL, 194 mm LEA, examined from photographs, DZUFMG 011, 2 (paratypes), 142-147 mm LEA, examined from photograph, MZUSP 67491 , 1 (paratype) , MZUSP 70004 , 1 (paratype), 141 mm, Estação Ecológica Juréia, rio do Descalvado, rio Una do Prelado dr., ca. 24°29′S, 047°14′W . FMNH 54543, 1, 153 mm, Iguape, rio Ribeira de Iguape dr., ca. 24°40′S, 047°32′W . MZUSP 83020 , 2 , immature, 60-65 mm, nr. Vila de Momuna, stream affl. rio Momuna, rio Ribeira de Iguape dr., 24°42′57″S, 47°41′27″W . MZUSP 93118 , 1 , male ( CS), 170 mm, stream, affl. rio Momuna, ca. 1.5 km Vila de Momuna, rio Ribeira de Iguape dr., 24°42′29″S, 47°40′53″W . MZUSP 100268 , 5 , (1 immature, 100 mm, 4 female, 149-169 mm), nr. Vila de Momuna, rio Bateçaria, affl. rio Momuna , rio Ribeira de Iguape dr., 24°42′56″S, 047°41′28″W .

Figures

Fig. 33. Brachyhypopomus jureiae. MZUSP 100268, female, 170 mm TL (head in lateral view, and body in lateral and dorsal view, specimen fixed in formalin and preserved in EtOH); Brazil, rio Bateçaria, rio Ribeira de Iguape dr. Scale bars = 5 mm.

Fig. 23. Collection records for Brachyhypopomus draco (circles), B. janeiroensis (squares), and B. jureiae (triangles). Holotype locations are marked with open symbols. Elevation data refers to altitude above mean sea level (see Fig. 2 for legend).