Creagrutus yudja, Netto-Ferreira & Moreira, 2018

Netto-Ferreira, Andre L. & Moreira, Cristiano R., 2018, New species of Creagrutus (Ostariophysi; Characiformes; Characidae) from the Rio Xingu drainage, Brazil, Zootaxa 4375 (2), pp. 250-256: 251-253

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Creagrutus yudja

new species

Creagrutus yudja   , new species

( Fig.1 View FIGURE 1 ; Table 1)

Holotype. MNRJ 48662 View Materials (26.7 mm SL) Brazil, Pará, Altamira, Praia do Levi, rio Iriri , Rio Xingu basin, 3º50'37"S 52º44'03"W, A. Gonçalves et al., 0 9 Jan 2013. GoogleMaps  

Paratypes. All from Brazil, Pará, Altamira: INPA 56751 View Materials (4, 22.5–24.1 mm SL)   ; MNRJ 44479 (5, 21.6–30.0 mm SL; 2 CS 22.7–26.8 mm SL); MZUSP 123261 View Materials (2, 23.4–26.1 mm SL), same data as holotype GoogleMaps   . MNRJ 44480 (5, 20.1–28.3 mm SL); MPEG 35268 View Materials (4, 21.6–26.7 mm SL), Praia do Amor close to Ilha da Fazenda, Rio Xingu , Volta Grande do Xingu , 3º34'40"S 51º54'37"W, A. Gonçalves et al., 23 Nov 2012. GoogleMaps  

Diagnosis. Creagrutus yudja   is distinguished from its congeners by the lack of infraorbital 6 (vs. present). Additionally, It differs from its congeners, except for C. cracentis   , C. maxillaris   , C. melanzonus   , C. phasma   , C. runa   , and C.veruina   , by having a shallower body (13.7–19.2% vs.> 20%). The new species can be further distinguished from C. cracentis   , C. maxillaris   , C. phasma   , C. runa   , and C.veruina   by the lower number of perforated lateral line scales (34–36 vs.> 37); and from C. melanzonus   by the higher number of post-anal scales (4- 6 vs. 2).

Description. Morphometric data of holotype and paratypes presented in Table 1. Small bodied species, maximum size registered 30.0 mm SL. Overall appearance elongate compared to most congeners. Greatest body depth between half distance between pectoral- and pelvic-fin origins. Head bullet-shaped in lateral view. Snout pronounced and round, mouth subterminal, profile of head strongly convex from upper lip to vertical through anterior margin of orbit. Slightly convex from that point to dorsal-fin origin, nearly straight from that point to anteriormost dorsal caudal-fin procurrent ray. Ventral profile of head slightly convex from lower lip to vertical through anterior border of orbit, nearly straight from that point to posterior border of isthmus. Ventral profile of body slightly convex from anterior margin of cleithrum to pelvic-fin origin. Slightly convex to straight from that point to anal-fin origin. Anal-fin base straight slightly posterodorsally slanted. Ventral profile of caudal peduncle, straight.

Upper jaw longer than, and overhanging, lower jaw. Premaxillary teeth visible in ventral view with mouth closed. Premaxillary teeth in three series. Primary series with 4(21), or 5(2) arranged in posterolaterally straight line, except for lateralmost tooth, aligned laterally with adjacent tooth, with distinct gap between first and second teeth. Three teeth in triangular cluster posterior lingually to primary series, anteriormost tooth aligned medially with second tooth of primary series. Single tooth aligned laterally with second tooth of primary series. All premaxillary teeth tricuspid, with size of teeth and cusps increasing posteromedially. Maxilla with 3(2), 4(17) or 5(2) tricuspid to conical teeth. Maxillary teeth decreasing in size posteriorly. Dentary with 5(3), 6(17), or 7(3) trito unicuspid teeth; three anterior teeth largest, posteriormost tooth distinctively small and conical. First gill arch with 1(1), or 2(1) gill-rakers on hypobranchial, 1(2) on cartilage between hypo- and ceratobranchial, 5(1), or 6(1) on ceratobranchial, 1(2) on intermediate cartilage, and 4(2) on epibranchial. Branchiostegal rays 4(2).

Scales cycloid, circuli and focus restricted to anterior, covered area of scales, with few weak, nearly parallel radii extending from focus to posterior margin of scales. Lateral line with 34(3), 35(6) or 36(1) perforated scales; slightly curved ventrally from humeral area to vertical through anal-fin terminus, becoming nearly straight from that point to lateral line scales onto caudal-fin rays. Longitudinal scale rows between dorsal-fin origin and lateral line 4(16), longitudinal scale rows between lateral line and pelvic-fin origin 2(15). Predorsal scales 10(1), 11(11), or 12(3). Scales between anus and anal-fin origin 4(2), 5(9), or 6(4). Few, smaller and elongate scales at base of anal fin. Circumpeduncular scales 13(5), or 14(3).

Pectoral-fin rays i,9(4), i,10(18), or i,11(1). Tip of pectoral fin not reaching vertical through pelvic-fin origin. Pelvic-fin rays i,6,i*(23). Tip of pelvic fin not reaching anal-fin origin. Rod-shaped supraneurals 5(2), anterior to 5th(2) to 9th(2) vertebral centra. Dorsal-fin rays ii,8(23). First dorsal-fin pterygiophore inserted immediately posterior to neural spine of 11th(2) vertebral centrum. Distal margin of expanded dorsal fin nearly straight. Dorsal fin originating slightly ahead middle of standard length, terminus anterior to vertical through anal-fin origin. Analfin rays ii, 7(1), 8(16), or 9(6). Distal margin of anal fin slightly concave. First anal-fin pterygiophore inserted immediately anterior of haemal arch of 18th(2) vertebral centrum. Adipose fin present. Caudal fin forked, lobes approximately equal in size. Principal caudal-fin rays i,9/8,i(23). Dorsal procurrent caudal-fin rays 10(2), ventral procurrent caudal-fin rays 9(1), or 10(1). Total vertebrae 36(2); precaudal vertebrae 15(2), caudal vertebrae 21(2).

Color in alcohol. Overall ground colour pale yellowish ( Fig. 1 View FIGURE 1 ). Chromatophores concentrated on top of head, from snout tip to supraoccipital spine. Small superficial chromatophores restricted to snout, larger deeper chromatophores associated with supraorbital sensory canal and dorsal surface of brain. Few scattered chromatophores ventral to nares, on premaxilla, and infraorbitals 1 and 2. Scattered chromatophores posterior to eye, on infraorbitals 4 and 5 and dorsal half of opercle. Middorsal and adjacent two scale rows with chromatophores concentrated on posterior margin of each scale. More concentrated on middorsal row and posterior to dorsal-fin. Vertically elongate humeral blotch, approximately rectangular, encompassing, one scale horizontally and three scales vertically, including scales of lateral line series. Chromatophores concentrated on midlateral of body, forming a longitudinal stripe from near supracleithrum to distal tip of median caudal-fin rays. Longitudinal stripe diffuse anteriorly, becoming progressively thinner and darker and more discernible posterior to dorsal fin. Pectoral and pelvic fins mostly hyaline except for few chromatophores on lateralmost pectoral-fin rays. Dorsal-fin rays with scattered chromatophores on anterior and posterior margins. Anal-fin rays with scattered chromatophores on anterior and posterior margins, more concentrated at base. Adipose fin with few chromatophores at base. Caudal fin with conspicuous dark stripe on middle rays, continuous with lateral stripe of body; scattered chromatophores on remainder of fin, mainly on dorsal and ventralmost principal caudal-fin rays, and procurrent rays.

Sexual dimorphism. Adult male specimens with small antrorse bony hooks on medial face of branched rays of pelvic fin. Hooks more numerous on first branched ray decreasing in number on subsequent rays, no more than two hooks per segment, except for basalmost segment.

Distribution. Creagrutus yudja   is only known from two localities in the Rio Iriri (Praia do Levi) and the Rio Xingu (Praia do Amor), both sandy beaches at the lower Rio Xingu basin, Pará, Brazil ( Fig. 2 View FIGURE 2 ).

Etymology. The new species is named after the Juruna indigenous people, self-named Yudjá. The Yudjá, which means “keeper of the river”, were numerous and inhabited the area of the lower and middle Xingu river. Nowadays the Yudjá have a population of approximately 900 individuals and are restricted to two areas, one at the Xingu Indigenous Park and other at the Volta Grande of Rio Xingu. The Yudjá have an overlapping area of occupancy with the new species described herein, and both are seriously threatened since the construction of the Belo Monte dam.