Species of Ancistrus (Siluriformes, Loricariidae) from Ecuador, with the description of a new species from the Amazon River Basin Author Provenzano, Francisco Author Barriga-Salazar, Ramiro text Zootaxa 2018 2018-12-05 4527 2 211 238 journal article 27858 10.11646/zootaxa.4527.2.4 78e71f21-bf4e-4cb6-9b39-ec297753e743 1175-5326 2612125 AD39D2F3-B8BB-4CC2-913B-D46A6B7E72D6 Ancistrus clementinae Rendahl, 1937 Table 3 Figures 2 , 3 , 6 Ancistrus clementinae Rendahl, 1937 . Arkiv för Zoologi v. 29 , häfte 3, A. no. 11:4, fig. 2. Río Clementina system, northwest of Babahoyo , Ecuador . Holotype (unique): NRM 10369. Material examined. All from Ecuador . Azuay province : MEPN-5984, 1, 99.4 mm SL, Río Siete, afluente del Río Fermín, Brazo del Pulga Guerrero, 03°01’47”S 79°43’00”W , R. Barriga, M. Guerrero, R. Jácome, 25 August 2007 . MEPN-5996, 10, 72.7–106.3 mm SL, Río Siete , afluente del Río Fermín , Brazo del Pulga Guerrero , 03°01’47”S 79°43’00”W , R. Barriga , M. Guerrero , R. Jácome , 25 August 2007 . MEPN-5997, 2, 90.3–95.3 mm SL, Río Siete , afluente del Río Fermín , Brazo del Pulga Guerrero , 03°01’47”S 79°43’00”W , R. Barriga , M. Guerrero , R. Jácome , 25 August 2007 . Los Ríos province : MEPN-11420, 22, 42.5–65.6 mm SL, Cuenca río Caluma , río La Clara cerca al puente, 01°38’11’’S 79°15’33’’W , N. Lujan , D. Taphorn , R. Barriga , 26 August 2012 . Guayas province : MEPN-9833, 1, 57.1 mm SL, Río Bucay , 3 km aguas abajo de Naranjal , 02°41’19”S 79°38’58”W , R. Barriga , 22 September1992 . MEPN-9837, 1, 91.0 mm SL, Río Canayacu a 7 km al Sur de Naranjal , Cooperativa La Nueva Unión , 02°43’24”S 79°39’53”W , R. Barriga , 24 September 1992 . Diagnosis. Ancistrus clementinae can be distinguished from species inhabiting the trans–Andean region and Ecuador by the arrangement of the soft, fleshy tentacles on the snout. Females don’t have small, conical, fleshy tentacles, on the ventral and central region of snout vs. presence of small conical tentacles on the ventral and central region of the snout, in females of trans–Andean and Ecuador species. Males have evident fleshy tentacles along the dorsal midline of the snout, two backward divergent rows of flat branched tentacles vs. single row of cylindrical and branched tentacles, along dorsal midline of the snout, in males, in the same condition, in species of trans– Andean region and Ecuador . Among the species found in Ecuador , A. clementinae have 18–22 movable cheek odontodes vs. 10 to 12, in the other three analyzed species. Additionally, this species has shorter dorsal fin and pectoral fin spines, 18.7%–25.8% SL vs. 24.3%–27.3% SL in A. shuar , 29.8%–33.4% SL in A. alga and 24.4%– 32.4% SL in A. malacops ; 19.5%–26.7% SL vs. 28.9%–33.6% SL in A. shuar , 31.9%–38.9% SL in A. alga and 28.5%–38.7% SL in A. malacops , respectively. Description. Morphometric data given in Table 3 . This species reaches smaller size than other three. Body depressed anteriorly, progressively compressed posteriorly. Caudal peduncle compressed, deep, robust. Dorsal profile of body convex from tip of snout through dorsal-fin origin. Descending straight from last point to adiposefin origin, then straight and horizontal to caudal-fin. Ventral profile of body flat and straight or slightly concave. Ventral surface of head and belly naked until anal-fin origin. Urogenital papilla not usually visible, in some mature males opening is partially visible just posterior to anus ( Figs. 2 , 6 ). Head moderately wide and depressed. Snout partially naked with or without fleshy cylindrical tentacles branched or not, its contour semicircular. In adult males, naked area is wider, reaches nares and orbits. Females and juveniles have only a narrow naked strip on snout border, fleshy tentacles are very small and located laterally only. Nostrils juxtaposed and closer to eyes than tip of snout. Eyes in dorso-lateral position, orbits not raised and without odontodes. Interorbital space broad and flat or gently conv, Supraoccipital flat without ridges, posterior border straight and truncate. Movable hypertrophied cheek odontodes well developed, specimens can have from 18–22. Odontodes size variable in each specimen, longest odontode, in mature males, reaches pectoral-fin origin. Anteriorly, bases of movable hypertrophied odontodes are ventrally covered with plates. Opercular bone has small exposed surface visible externally, its lateral margin carries few odontodes. FIGURE 6. Ancistrus clementinae , MEPN 5996, 94.6 mm SL, male. From top to bottom, lateral, dorsal, and ventral view. FIGURE 7. Ancistrus malacops , MEPN 14705, 117.8 mm SL, male. From top to bottom, lateral, dorsal and ventral view. Mouth rounded or oval. Upper lip narrow, usually covering premaxillary and only external surface is visible, its edge is almost horizontal, and with very small papillae, its internal surface papillose. Lower lip broad, its border smooth or with very small papillae, its surface with papillae that are smaller near border of lip but increase in size near lower jaws. Papillae of anterior lip have similar size to those near lower jaws. Maxillary barbels very short, inconspicuous, only tip is free. Upper jaw a little longer than lower. The upper jaws are straight, and placed horizontally. Lower jaws form an open V between them. Teeth numerous and minute. Between 40–50 teeth in upper jaw and between 35–45 teeth in lower jaw. Premaxillary and dentary teeth of same size. Teeth incisor type , asymmetrically bifid, medial cusp longer and wider than lateral cusp. Medial cusp rounded or straight truncated, lateral cusp pointed. Tooth apex curved toward interior of mouth. Tooth apex yellowish, stalk whitish. Premaxillary and dentary without posterior papillae or ornamentation. FIGURE 8. Map of Ecuador showing the geographical distribution of the species. A. shuar , star. A. alga , square. A. clementinae , circle. A. malacops , triangle. Symbols may represent more than one lot. TABLE 3. Morphometric data of Ancistrus clementinae . Measurements are expressed as percentage of standard length. N=9

Character	Average	STD	Min.	Max.
SL (mm)	62.5	110.8
Head length	36.9	1.1	34.7	38.4
Predorsal length	46.9	0.7	45.8	48.2
Postdorsal length	37.3	1.5	35.2	39.8
Interdorsal length	19.3	1.5	17.0	21.7
Preanal length	67.6	1.8	64.8	70.8
Postanal length	31.0	1.3	28.7	33.0
Thoracic length	23.4	1.3	21.1	25.6
Abdominal length	21.1	1.2	20.1	23.8
Dorsal fin base	19.8	0.8	18.6	20.9
Dorsal spine length	23.9	2.2	18.7	25.8
Pectoral spine length	23.7	2.3	19.5	26.7
Pelvic spine length	21.5	2.1	18.5	23.7
Cleithral width	27.9	1.6	25.4	30.2
Caudal peduncle depth	11.9	0.7	10.3	12.7
Head depth	19.6	1.2	17.7	20.9
Snout length	21.5	1.4	19.8	24.6
Interorbital width	14.3	0.6	13.1	15.2
Orbital diameter	5.5	0.5	4.9	6.5
Mandibular ramus length	4.7	0.5	4.2	5.8

Lateral line plates 24–25. Post-anal plates 12–13. Inter-dorsal plates seven or eight, the plate just in front of the adipose-fin spine has small keel, and seems to be an isolated plate, different from the anterior plates. Dorsal-fin origin anterior to vertical passing through pelvic-fin origin. Dorsal-fin with one spine, followed by seven branched rays; when depressed does not reaches adipose-fin origin. Adipose fin always present, but the membrane scarcely or not developed. Adipose-fin spine straight. Pectoral-fin with one spine, and six branched rays. Pectoral-fin spine almost reaches pelvic-fin origin when depressed. The spine is shorter than first three branched rays. Distal region of pectoral-fin spine with fleshy tip, and with enlarged odontodes, more developed in males. Pelvic-fin with one spine and five branched rays; its posterior margin surpass anal-fin base when depressed. Anal-fin with one flexible spine and four branched rays. Distal margin of caudal-fin truncate and a bit oblique, but in some specimens rounded. The lower spine is a bit longer than upper spine, or of same length; caudal-fin rays i,14,i. Sexual dimorphism. Adult males of A. clementinae have dorsolateral naked area on snout. Tentacles are arranged as follows: Snout edge with three or four rows of small conical tentacles. Tip of the snout, with a patch of tentacles, some of them bifid or branched. Starting at the tip of snout, a dorsal midline of two or three conical and bifid or branched tentacles runs backward. This row quickly splits into two new rows of flat branched tentacles, ending in front of the nostrils. Lateral to the rows of tentacles, the naked area of the snout have papillae and/or conical tentacles, small or very small, randomly arranged. Just in front of each nostril a slightly longer, flat, branched tentacle is found ( Fig. 6 ). Also in this species, some samples have males without or with only small (vestigial), soft, fleshy tentacles on dorsal midline of snout. Females have the similar narrow naked strip on snout border, but they do not have the usually small fleshy conical tentacles on the border. Some females have a very small conical tentacles just in front of movable cheek odontodes ( Figs. 2 , 3 ). Color. Head, and dorsolateral surface of body varies from light to dark brown or black with irregular scattered, pale or whitish areas, sometimes perceived as white or cream, rounded blotches. Some specimens have dark brown or black, irregular transverse bands on dorsolateral surface of the body. Belly is whitish or cream and uniform, but some specimens have a vermiculated dark pattern. Color pattern in all fins, except the anal-fin with four to six, dark blotches or dots on rays, occasionally forming horizontal or transverse stripes; interradial membrane is translucent, and the distal border of fins white. Anal-fin with two dark blotches or dots on rays ( Figs. 2 , 6 ). Geographical distribution. Ancistrus clementinae is found in the Pacific versant of Ecuador , mostly in drainages that flow to the Guayas River Basin ( Fig. 8 ).