Hisonotus jumaorum, Dias & Silva & Oliveira & Roxo, 2018

Dias, Angelica C., Silva, Gabriel S. C., Oliveira, Claudio & Roxo, Fábio F., 2018, A new species of Hisonotus (Siluriformes: Loricariidae) from Aripuanã river, Amazon basin, Brazil, Zootaxa 4504 (4), pp. 577-585 : 578-581

Hisonotus jumaorum , new species

Fig. 1 , Table 1

Holotype. MZUSP 123835 , female, 26.2 mm SL, Brazil, Amazonas state, municipality of Apuí, rio Juma, tributary of rio Aripuanã , rio Madeira basin, 7°12’43.7”S 59°55’19.6”W, 22 June 2015, W. M. Ohara & V. Abrahão.

Paratypes. All from Brazil, rio Madeira basin. LBP 25850, female, 21.2 mm SL, collected with the holotype. MZUSP 117603 , 2 , 21.3 ¯ 24.3 mm SL, collected with the holotype. MZUSP 117710 , 1 , 22.5 mm SL, municipality of Apuí , rio Juma , tributary of rio Aripuanã, rio Madeira basin, 7°12’43.7”S 59°55’19.6”W, 22 June 2015, W. M. Ohara & V. Abrahão .

Diagnosis. Hisonotus jumaorum can be diagnosed from all congeners, except H. chromodontus , by having reddish-tipped teeth, Fig. 2a, b (vs. hyaline or yellowish-tipped teeth, Fig. 2c, d ). Additionally, the new species can be distinguished from all congeners, except H. acuen , H. bockmanni , H. chromodontus and H. vespuccii Roxo, Silva & Oliveira, 2015a by having a V -shaped spinelet (vs. rounded, rectangular or triangular-shaped spinelet). Hisonotus jumaorum can be distinguished from H. acuen , H. chromodontus and H. vespuccii by having three lateral plates in the abdominal series (vs. four to five in H. acuen and H. chromodontus , and six to seven in H. vespuccii ) and by having the caudal-fin color hyaline with three transverse dark bars, Fig. 3a (vs. two hyaline rounded areas on the upper and lower lobes in H. chromodontus , Fig. 3b or a dark brown chromatophores largely concentrated on rays near lower caudal spine in H. acuen and H. vespuccii , Figs. 3c,d ). Furthermore, the new species can be diagnosed from H. chromodontus by lower number of lateral plates in the median plate series, 21–22 (vs. 23–24) and by head length, 36.6–40.3% SL (vs. 27.5–35.5% SL); and from H. vespuccii by having odontodes randomly distributed on head and trunk (vs. odontodes forming longitudinally aligned rows, one odontode after the other, but not necessarily forming parallel series, on head and trunk, see character definition in Fig. 2 of Roxo et al. 2014b).

Description. Morphometric and meristic data presented in Table 1. Small size (21.3–26.2 mm SL). In dorsal view, snout tip pointed (57.4–59.1% HL). Margin of snout covered by odontodes, larger than rest of head. Snout tip without naked area, covered by plates and odontodes. Eyes small (11.0–14.2% HL), dorsolaterally positioned, superior margin of orbits not elevated. Iris operculum absent. In lateral view, dorsal profile of head almost straight, depressed, slightly concave from snout tip to area between nostril, straight to parieto-supraoccipital. Head completely covered by bony plates, except on ventral portion of head, at mouth region and between lower lip and scapular bridge. Bony plates covered by odontodes randomly arranged, not forming aligned rows. Head without conspicuous crests. Mouth located in ventral portion of body. Lower lip small, not reaching transversal line through gill openings; naked area between lower lip and scapular bridge large and slightly concave, twice larger than lower lip. Small papillae randomly distributed through lower lip and increasing in size proximally. Buccal papilla absent. Reddish-tipped teeth, slender and bifid.

In lateral view, dorsal profile of trunk slightly convex from tip of snout to posterior margin of parietosupraoccipital, slightly concave from that point to dorsal-fin insertion, straight from that point to dorsal caudal-fin insertion. Ventral profile slightly convex from snout tip to opercular region, convex from that point to anal-fin insertion, slightly concave from that point to caudal peduncle, straight to ventral caudal-fin origin. Greatest body depth at dorsal fin origin; greatest body width at cleithral region (23.8–24.5% SL); narrowing anteriorly to snout tip and posteriorly to caudal peduncle. Trunk covered by bony plates, except on dorsal-fin base and pectoral, pelvic and anal fins insertion. Median plate series with 21–22 plates; lateral line complete. Abdominal region entirely covered by slender plates; lateral abdominal plate series with three plates; 5–6 irregular plates on median series; three large plates on anal series. Large naked area around pelvic-fin insertion.

Dorsal-fin rays II,7; dorsal-fin spinelet V -shaped, almost reaching half of anal-fin unbranched ray when depressed; dorsal-fin locking mechanism functional; dorsal portion of dorsal-fin spine covered by odontodes, more developed distally. Pectoral-fin rays I,6; reaching half of pelvic-fin unbranched ray when depressed; pectoral spine covered by odontodes on dorsal surface, larger on distal portion. Pectoral-fin axillary slit present (more visible in large specimens as holotype). Pelvic-fin rays i,5; not reaching anal-fin insertion when depressed; pelvic-fin spine covered by odontodes, curved inward on ventral surface. Anal-fin rays i,5; anal-fin spine covered by odontodes, more developed distally. Caudal-fin rays i,14,i; forked, all rays covered with odontodes; odontodes more developed on distal portion of dorsal and ventral caudal-fin spine. Total vertebrae 28 (only holotype radiography). Caudal peduncle ellipsoid in cross-section, round laterally, flat dorsally and ventrally.

Color in Alcohol. Background coloration, in dorsal and lateral view dark-brown, in ventral view cream. Two hyaline bars from tip of snout to each naris, forming a V -shaped hyaline stain. Dorsal portion of trunk with five hyaline longitudinal stripes: one at dorsal-fin insertion, second at middle portion of dorsal-fin, third at posterior margin of dorsal-fin spine, fourth at typical adipose-fin region and fifth at upper caudal-fin spine insertion. Dorsalfin hyaline with three transversal dark stripes: one almost inconspicuous at proximal portion, one at middle portion and one at distal portion. Pectoral-fin hyaline with five inconspicuous dark strips on dorsal surface. Pelvic-fin hyaline, without strips. Anal-fin hyaline, with two inconspicuous strips. Caudal-fin possessing three transversal dark bars: first at origin of branched rays, second at middle portion of caudal-fin, and third at distal portion of rays. In lateral view, a large dark band at median portion of body in lateral line from tip of snout to end of caudal peduncle. In ventral view, body yellowish, with concentration of chromatophores around anal-fin base and along caudal peduncle.

Distribution. The new species is only known from the type locality at rio Juma, tributary of lower rio Aripuanã, rio Madeira basin, municipality of Apuí, Amazonas state, Brazil. The type locality of this species is an area between two Legal Amazon Conservation Units, Floresta Nacional do Aripuanã and Floresta Nacional do Jatuarana. This area is constantly threatened by mining and deforestation.

Etymology. The specific name “jumaorum” is related to the large Indian tribe (Juma) that were butchered and wiped out of the region around the Juma river. In the 18th century, the Juma had a population of about 15 thousand people. Nowadays, the survivors of the Juma people comprise only one nuclear family with a father and three daughters (source “Povos Indígenas no Brasil ” https://pib.socioambiental.org/en/Povo:Juma).

Figures

FIGURE 1. Hisonotus jumaorum, MZUSP 123835, 26.2 mm SL, holotype, Brazil, Amazonas state, municipality of Apuí, rio Juma, tributary of rio Aripuanã, rio Madeira basin. Dorsal, lateral and ventral views.

FIGURE 2. Comparison of Hisonotus tooth color pattern. a) Hisonotus jumaorum sp. n., holotype, MZUSP 96785, 26.2 mm SL and b) H. chromodontus, NUP 10924, 29.7 mm SL, showing the reddish-tipped teeth; c) H. acuen, MZUSP 115350, 25.9 mm SL and d) H. vespuccii, LBP 19491, 38.0 mm SL, showing the yellow-tipped teeth.

FIGURE 3. Caudal-fin coloration pattern of a) Hisonotus jumaorum sp. n., holotype, MZUSP 96785, 26.2 mm SL; b) H. chromodontus, LBP7964, 27.6 mm SL; c) H. acuen, LBP 16279, 26.1 mm SL; and d) H. vespuccii, LBP 19491, 26.2 mm.