Aphanotorulus rubrocauda, Oliveira & Py-Daniel & Zawadzki, 2017

Oliveira, Andreza S., Py-Daniel, Lúcia Rapp & Zawadzki, Cláudio H., 2017, A new species of Aphanotorulus (Siluriformes: Loricariidae) from the rio Aripuanã basin, Brazil, Neotropical Ichthyology 15 (1), No. e 160034, pp. 1-10 : 2-7

Aphanotorulus rubrocauda , new species

urn:lsid:zoobank.org:act:E3B44D1F-C9B4-45A1-AF13-AB4F1AB40F65

Figs. 1-2

Hypostomus emarginatus . - Pedroza et al., 2012: 13 [species list; rio Guariba and rio Roosevelt, tributaries of rio Aripuanã basin].

Aphanotorulus horridus . - Ray, Armbruster, 2016: 521 [taxonomic revision of Aphanotorulus and Isorineloricaria ].

Holotype. INPA 33666, 150.5 mm SL, Brazil, Amazonas State , Apuí Municipality , rio Guariba , Resex do Guariba, tributary of the rio Aripuanã basin, 08°45’44”S 60°24’48”W, 15 Nov 2008, W. S. Pedroza, W. M. Ohara, F. R. V. Ribeiro & T. F. Teixeira.

Paratypes. All from Brazil. Rio Aripuanã basin: Amazonas State : INPA 33636 , 5 , 150.2 - 220.3 mm SL (1 c&s, 150.2 mm SL), Apuí Municipality, rio Guariba, Resex ( Extractive Reserve ) do Guariba , tributary of the rio Aripuanã basin, 08°45’03”S 60°26’10”W, 07 Nov 2008, W. S. Pedroza, W. M. Ohara, F . R. V. Ribeiro & T. F. Teixeira . INPA 52205 , 1, 187.4 mm SL (same data of the holotype) . INPA 52436 , 2 , 69.3-86.9 mm SL, Novo Aripuanã, boulders on rapids above Prainha , 07°17’13.00”S 60°37’59.0”W, Nov 2014, E. D. Ribeiro , R. Collins & V. Machado . INPA 52448 , 3 , 145.8 -195.0 mm SL, Novo Aripuanã Municipality, boulders on rapids below Prainha , 06°59’56.00”S 60°40’9.00”W, Nov 2014, E. D. Ribeiro , R. Collins & V. Machado. Mato Grosso State : INPA 31868 , 1, 173.2 mm SL, Aripuanã Municipality, Cisga , 10°09’9.23”S 59°26’9.40”W, 29 Sep 1975, F. Marinho . MNRJ 36331 , 2 , 182.4 -218.0 mm SL, Aripuanã Municipality, about 100 meters downstream of Dardanelos waterfalls, 10°9’48”S 59°26’56”W, 31 Mar 2008, F. Pupo & R. Paiva . MNRJ 37551 , 1, 118.6 mm SL, Aripuanã Municipality, rio Aripuanã, 500 meters downstream of Dardanelos waterfalls, 10°09’47”S 59°26’41”W, 05 May 2009, F. Pupo . MNRJ 38829 , 1 , 95.6 mm SL, Aripuanã Municipality, rio Aripuanã, left margin, 1500 meters downstream of Dardanelos waterfalls, 10°09’33”S 59°26’20”W, 09 Feb 2011, F. Pupo . MNRJ 38943 , 2 , 173.5 - 222.5 mm SL, Aripuanã Municipality, left margin, 1500 meters downstream of Dardanelos waterfalls, 10°09’30”S 59°26’19”W, 11 Dec 2008, F. Pupo . MNRJ 39824 , 3 , 132.2 - 180.5 mm SL, Aripuanã Municipality, rio Aripuanã, left margin, 500 meters downstream of Dardanelos waterfalls, 10°09’53”S 59°26’57”W, 20 Dec 2010, F. Pupo . MZUSP 37594 , 5 , 155.9 - 226.5 mm SL, Aripuanã Municipality, rio Aripuanã, 3 kilometers downstream of the Cachoeira Grande , 09°57’23.7”S 59°19’45.9”W, 08 Nov 1976, Expedição MZUSP / INPA. MZUSP 60372 , 1 , 144.0 mm SL, Aripuanã Municipality, Porto de Balsa (upstream), road connecting the district of Colniza Panelas , kilometer 18, 09°21’10.5”S 59°19’32.3”W, 22 Jul 1997, F. Machado . MZUSP 104456 , 5 , 192.5 - 239.2 mm SL, Aripuanã Municipality, 3 kilometers below of the Cachoeira Grande ( Dardanelos waterfalls), 10°09’00”S 59°26’00”W, 07 Nov 1976, Expedição MZUSP / INPA. NUP 7458 , 4 , 125.3 - 215.5 mm SL, Aripuanã Municipality, small stream with unknown name, tributary of igarapé Guaribal, 10°06’35”S 59°26’12”W, 19 May 2008, I. M. Fernandes. NUP 7785, 6, 158.5- 234.5 mm SL, Aripuanã Municipality , unnamed small stream, tributary of igarapé Guaribal , 10°06’35”S 59°26’12”W, 19 May 2008, I. M. Fernandes . UFRO-I 21197 , 5 , 158.6 - 212.5 mm SL, Rondolândia Municipality, rio Madeirinha, boulders on rapids, 40 minutes motorized canoe, above of the Comil farm, 09°24’42.2”S 61°22’0.4”W, 12 Jul 2013, D. G. Hungria . UFRO-I 21647 , 2 , 132.6 - 159.8 mm SL, Colniza Municipality, rio Roosevelt , boulders on rapids, 09°09’48.7”S 60°44’33.5”W, 13 Jul 2013, W. M. Ohara . UFRO-I 21648 , 1, 126.2 mm SL, Colniza Municipality, rio Branco , 09°08’43.1”S 60°45’03.5”W, 14 Jul 2013, W. M. Ohara . UFRO-I 21672 , 5 , 72.4-240.5 mm SL, Colniza Municipality, rio Roosevelt , 09°08’43.1”S 60°45’03.5”W, 14 Jul 2013, B. S. F. Barros . UFRO-I 22039 , 1 , 91.0 mm SL, Colniza Municipality, rio Roosevelt , 09°09’46.82”S 60°44’31.43”W, 14 Jul 2013, D. G. Hungria . UFRO-I 22081 , 1, 156.7 mm SL, Colniza Municipality, boulders on rapids in the rio Aripuanã, Pai da Mata farm, 09°15’45.79”S 59°23’10.6”W, 17 Jul 2013, D. G. Hungria . UFRO-I 22685 , 5 , 172.7 - 238.5 mm SL, Colniza Municipality, boulders on rapids in the rio Aripuanã, farm Pai da Mata , 09°15’45.79”S 59°23’10.60”W, 17 Jul 2013, D. G. Hungria .

Diagnosis. Aphanotorulus rubrocauda can be distinguished from all other species of Aphanotorulus by its color pattern: having a uniformly red colored lower caudal-fin lobe (vs. lower lobe of caudal fin with dark spots on creamy colored background), by the absence of dark spots on the posterior half of mid-ventral lateral plate series (vs. presence of dark spots in all lateral plate series). Additionally, Aphanotorulus rubrocauda is distinguished from congeners by having more premaxillary teeth (32-65 per ramus, mean = 45; vs. 15-34, mean = 24) and dentary teeth (30-63 per ramus, mean = 44; vs. 14-34, mean = 25). Aphanotorulus rubrocauda further differs from A. emarginatus by having small round dark spots (vs. dark large and elongated spots) ( Fig. 3).

Description. Morphometric and count data are given in Tab. 1. Long and moderately depressed body in lateral view; body trapezoid in cross section. Dorsal profile slightly convex from snout to dorsal-fin origin, then descending almost straight to caudal-fin procurrent ray and rising again to caudal-fin origin. Ventral profile straight from snout to caudalfin origin. Median series of plates slightly carenate; midventral series not forming prominent keel. Greatest body width anterior to cleithral region. Scapular girdle and abdominal surfaces covered by small plates of uniform size. First anal-fin pterygiophore exposed, located anterior to anal-fin origin, in ventral view. Three pre-dorsal plates. Supraoccipital usually with small median ridge and bordered by three plates. Nine plates between dorsal and adipose fin. Seven plates at dorsalfin base. Median series with 28 perforated plates.

Head short, depressed and triangular in dorsal view. Snout tip slightly rounded with small odontodes. Orbit slightly elevated, bordered by small odontodes; flat interorbital region. Eyes moderately large (15.1-22.1% in HL). Maxillary barbel short, cylindrical, not reaching transverse line on lower lip edge. Presence of large buccal papilla, square and wide, covered distally by multiple small papillae. Mouth wide. Upper lip rounded in ventral view and without marginal fringes. Lower lip rounded and covered with papilla, decreasing in size distally. Odontodes present on anterior surface of snout ventral edge. Cheek plates with non-evertible odontodes usually small; more developed in reproductive males.

Bicuspid teeth; mesial cusp longer and rounded, two times larger than lateral teeth; lateral cusp pointed. Teeth stalk hyaline; crown yellow. Mature males, with mesial cusp more elongated, up to three times longer than lateral. Premaxilla with 33-57 teeth (mode = 45, n = 62), dentary with 31-58 teeth (mode = 44, n = 62).

Dorsal fin II,7, branched rays decreasing in length posteriorly. Last branched ray 2/3 shorter than dorsal-fin spine. Pectoral fin I,6; distal tip of branched rays surpassing insertion of pelvic fin; pectoral-fin spine slightly curved inward and depressed, distal region with hypertrophied odontodes along laterodorsal surface in larger specimens. Pelvic fin i,5, distal tip of branched rays reaching insertion of anal-fin. Pelvic fin unbranched ray slightly curved inward and rounded with thin extremity. Forked caudal fin i,14,i. Unbranched ray of lower lobe slightly longer than that from upper lobe. All rays with small odontodes. Caudal fin with seven branched rays in each lobe. Anal-fin branched rays of coequal length.

Coloration in alcohol. Body with light brown base color covered with rounded dark spots; spots slightly smaller and more densely organized on head than on trunk and fins. Distal portion of pectoral and pelvic fins hyaline and without dark spots. Dorsal-fin spine with 16-17 spots, inter radial membranes with 10-11 spots each; branched rays uniformly colored. Spots on pectoral fin arranged from insertion to distal end of all fin rays. Pelvic fin with spots from insertion to distal third; plain or hyaline along margin. Presence of dark spots on lateral series of plates, except on mid-ventral and ventral series. Upper lobe of caudal fin cream colored with dark spots on simple and branched rays; lower lobe lacking spots, uniformly reddish to brown. Red coloration on lower caudal fin lobe restricted to branched rays; unbranched ray almost uniform. Dark spots on body and fins becoming more numerous in adults ( Figs. 1-2).

Coloration in life. Similar to preserved specimens, but more intensely red on lower lobe of caudal fin. In juveniles (up to 110.0 mm SL) both lobes are red, with a few dark spots on base of upper lobe. In adults only the lower lobe is red, whereas the upper lobe has more sparsely distributed spots for its entire extension ( Fig. 2).

Geographical distribution and ecological notes. The new species was found in fast-running waters of tributaries of the rio Aripuanã basin, a right bank tributary of the rio Madeira that stretches from the Mato Grosso to Amazonas States ( Fig. 4). The rio Aripuanã is a dark-colored water river, poor in sediments, having cataracts, large boulders and a rocky bottom from its middle reach upward, stretching approximately 800 km from its headwaters until its confluence with the sediment-loaded rio Madeira. The rio Aripuanã receives many clear-water, rocky-bottom tributaries that drain the Brazilian Shield.

Etymology. The specific epithet, rubrocauda , is from the Latin rubro, meaning red, and cauda referring to caudal fin.

Conservation status. Aphanotorulus rubrocauda , under the IUCN standards, should be considered as a Least Concern species (LC). The species occurs in preserved areas; it is frequently seen although not abundant. No current threats were identified that could endanger the species for now.

Comparative material examined. Aphanotorulus emarginatus : Brazil: DZSJRP 3920, 1, 171 mm SL. LBP 17160, 2, 134.9- 158.1 mm SL. LBP 17182, 2, 116.1- 125.4 mm SL. INPA 22138, 1, 270.1 mm SL. INPA 25716, 1, 168.2 mm SL. INPA 28771, 5, 78.9-206.5 mm SL. INPA 36082, 1, 272.5 mm SL. INPA 36637, 2, 165.7- 179.6 mm SL. MCP 30623, 1, 132.4 mm SL. MZUSP 40908, 1, 149.6 mm SL. MZUSP 82178, 4, 257.5- 324.5 mm SL. MZUSP 82247, 9, 90.9- 103.8 mm SL. NUP 9257, 1, 146.3 mm SL. NUP 10951, 1, 186.5 mm SL. Colombia: USNM 181367, 1, 194.0 mm SL. Venezuela: ANSP 185287, 1, 118.8 mm SL. Aphanotorulus phrixosoma . Brazil: ANSP 68650, 1, 110.6 mm SL, holotype of Plecostomus phrixosoma Fowler, 1940a: 233 .AMNH 12604, 1, 165.2 mm SL. LBP 166, 5, 105.1- 147.6 mm SL. MZUSP 49839, 1, 191.5 mm SL. MZUSP 50378, 1, 146.8 mm SL. MZUSP 50493, 1, 173.0 mm SL. MZUSP 50495, 1, 157.0 mm SL. Peru. ANSP 73174, 2, 117.6- 122.9 mm SL. USNM 167887, 2, 125.0- 186.93 mm SL. Aphanotorulus unicolor . Brazil: INPA 24951, 3, 48.2-92.2 mm SL. MZUSP 49659, 6, 51.4-87.7 mm SL. MZUSP 49682, 3, 50.2-125.6 mm SL. MZUSP 50488, 1, 108.6 mm SL. UFRO-I 6096, 1, 107.2 mm SL. UFRO-I 6104, 5, 77.8-93.8 mm SL. UFRO-I 6107, 1, 92.5 mm SL. Hypostomus carinatus . Brazil: INPA 41833, 2, 156.5- 166 mm SL. Hypostomus cochliodon . Brazil: NUP 12069, 2, 125.5- 151.5 mm SL. NUP 12071, 2, 145.5- 151.3 mm SL. NUP 12670, 1, 155.5 mm SL. NUP 13479, 5, 49.0- 160.8 mm SL. Hypostomus delimai . Brazil: ANSP 192612, 1, 202.1 mm SL, paratype of Hypostomus delimai Zawadzki, de Oliveira & Debona, 2013: 74 . INPA 20473, 1, 167.1 mm SL, paratype of Hypostomus delimai Zawadzki, de Oliveira & Debona, 2013: 74 . ZUEC 7088, 1, 200.7 mm SL. Hypostomus faveolus . Brazil: INPA 20069, 1, 145.1 mm SL. INPA 20452, 1, 168.4 mm SL. Hypostomus hoplonites . Brazil: INPA 2372, 1, 168.9 mm SL. INPA 35309, 2, 101.1- 173.3 mm SL. Hypostomus macushi . Brazil: INPA 2559, 1, 148.2 mm SL. Hypostomus cf. pantherinus . Brazil: INPA 35312, 1, 175.7 mm SL. Hypostomus paranensis . Bolivia: ANSP 88424, 1, 248.5 mm SL. ANSP 95873, 4, 111.8- 136.6 mm SL. Hypostomus plecostomus . Brazil: INPA 33663, 1, 178.7 mm SL. INPA 38694, 1, 184.0 mm SL. Guyana: CAS 56704, 2, 107.7- 134.2 mm SL. Venezuela: SU 62517, 1, 183.5 mm SL. Hypostomus pyrineusi . Peru: ANSP 180718, 1, 175.8 mm SL. Hypostomus regani . Brasil: LBP 3188, 4, 123.7- 147.8 mm SL. Hypostomus soniae . Brazil: INPA 33974, 3, 132.5- 147.6 mm SL. INPA 35324, 1, 172.4 mm SL. Hypostomus tenuis . Suriname: RMNH 16198, 1, 196.1 mm SL, holotype of Hypostomus tenuis Boeseman, 1968: 64 . Hypostomus watawata . Guyana: BMNH 1932.11.10.31, 261.2 mm SL, neotype of Hypostomus watawata Hancock, 1828: 246 , designated by Boeseman, (1968: 71). RMNH 3101, 1, 120.7 mm SL, paralectotype of Hypostomus watawata Hancock, 1828: 246 , designated by Boeseman, (1968: 71). Suriname: RMNH 21434, 1, 115.3 mm SL. RMNH 21435, 1, 135.5 mm SL. Isorineloricaria spinosissima . Ecuador. AMNH 58373, 10, 44.3-120.4 mm SL. BMNH 1898.11.4.32, 1, 357.6 mm SL, syntype of Plecostomus spinosissimus Steindachner, 1880: 98 . Isorineloricaria villarsi . Colombia: ANSP 139262, 3, 114.9- 237.5 mm SL. CAS 13915, 6, 105- 141.6 mm SL. NMW 44294, 1, 179.7 mm SL, syntype of Plecostomus villarsi Lütken, 1874: 211 . Venezuela: ANSP 134482, 1, 205.5 mm SL. AMNH 242814, 1, 115.6 mm SL. CAS 64374, 1, 115.7 mm SL. CAS 64381, 1, 98.4 mm SL. USNM 121030, 1, 188.0 mm SL.