Redescription of Ancistrus greeni (Siluriformes: Loricariidae), and description of a new species from the río Madre de Dios basin, Peru Author Bifi, Alessandro Gasparetto Author Ortega, Hernán text Neotropical Ichthyology 2020 Neotrop. Ichthyol. 18 1 http://dx.doi.org/10.1590/1982-0224-2019-0070 journal volume 10.1590/1982-0224-2019-0070 1982-0224 10960551 B0B62C38-2D9A-4F59-8310-FE9ABFED0075 Ancistrus maldonadoi , new species urn:lsid:zoobank.org:act: ED1397C7-5087-4EB8-94D8-326A42AEEE2D ( Fig. 4 , Tab. 2 ) Holotype . MUSM 57733, 114.7 mm SL, male, Peru , Manu District , Manu Province , río Madre de Dios basin, río Salvación , 12º55’05”S 71º27’36”W , 21 May 2006 , M. Hidalgo. Paratypes . Peru : río Madre de Dios basin : INPA 58921 , 10 , 40.6–101.9 mm SL (2, 68.6–101.9 mm SL), Manu , Parque Nacional del Manu , quebrada Culli , ca. 12º10’S 71º00’W , 5 Sep 1988 , H. Ortega et al .; MPUJ 14358 , 2 , 68.9–72.7 mm SL, same data from holotype ; MUSM 3763 , 1 , 87.0 mm SL, Manu , Salvación , quebrada Culli , 12º51’S 71º23’W , 5 Sep 1988 , H. Ortega ; MUSM 11620 , 1 , 77.5 mm SL, Sandia , Zona Reservada Tambopata Candamo , río Ebehua-baeji basin, río Beshuajali , 13º14’45”S 70º00’02”W , 25 Jul 1997 , F. Chang ; MUSM 11665 , 2 , 68.3–81.1 mm SL, Sandia , Zona Reservada Tambopata Candamo , río Ebehua-baeji basin, río Explorada , 13º14’34”S 70º00’01”W , 28 Jul 1997 , F. Chang ; MUSM 57732 , 4 , 58.0– 64.2 mm SL (2, 61.6–64.2 mm SL), same data from holotype ; MUSM 57832 , 5 , 61.5–147.2 mm SL (4, 74.5–147.2 mm SL), Paucartambo , Pillcopata , Tono , rio Huacarya , 12º55’05”S 71º27’36”W , 13 May 2006 , M. Hidalgo ; MUSM 58079 , 2 , 47.6–74.4 mm SL (1, 74.4 mm SL), Paucartambo , Pillcopata , río Queros , 12º56’41”S 71º21’22”W , 17 May 2006 , M. Hidalgo ; MUSM 58521 , 6 , 49.5– 76.3 mm SL (2, 65.6–67.6 mm SL), Paucartambo , Pillcopata , Queros , río Sabaluyoc , 12º56’38”S 71º21’09”W , 17 May 2006 , M. Hidalgo ; MUSM 58671 , 4 , 40.9 –83.0 mm SL (1, 83.0 mm SL), Quispicanchis , Camanti , río Inambari basin, stream without name, 13º11’29”S 70º33’16”W , 7 Aug 2010 , M. Hidalgo ; MZUSP 125014 , 2 , 85.1–85.4 mm SL, Paucartambo , Pillcopata , Queros , río Sabaluyoc , 12º56’38”S 71º21’09”W , 17 May 2006 , M. Hidalgo ; NUP 21719 , 2 , 70.4–75.6 mm SL, Paucartambo , Pillcopata , Queros , río Sabaluyoc , 12º56’38”S 71º21’09”W , 17 May 2006 , M. Hidalgo . FIGURE 4 | Ancistrus maldonadoi, MUSM 57733, holotype, 114.7 mm SL, male, Peru, Manu, río Madre de Dios basin, río Salvación. Diagnosis. Ancistrus maldonadoi is diagnosed from congeners, except A. greeni , by having unicuspid teeth ( vs. bicuspid). Ancistrus maldonadoi is diagnosed from A. greeni by larger orbital diameter 13.8–20.6% of HL ( vs. 8.8–13.0%); and longer adipose-fin spine (adipose spine length 7.2–9.5% of SL vs. 3.7–6.3%). Furthermore, A. maldonadoi is distinguished from the species described from rio Madre de Dios basin by larger dentary width 25.9–31.4 % of HL ( vs. 18.0–21.3% in A. montanus ); deeper caudal peduncle (12.2–14.0% of SL; vs. 9.4–11.2% in A. marcapatae , 9.6–10.5% in A. megalostomus , and 10.1–10.7% in A. montanus ). Description. Morphometric data and counts in Tab. 2 . Head and trunk moderately depressed with body depth greatest at supraoccipital. Dorsal profile of body convexly raising from tip of snout to dorsal-fin origin, then straight or slightly convex to adipose fin, and concave from that point to caudal fin. Ventral profile of body straight, slightly convex on caudal peduncle. Caudal peduncle compressed; slightly flattened ventrally. Head moderately large and wide; snout large and rounded in dorsal view, with large naked margin bordered by dermal platelets on lateral portion in males. Adult males with middle- to large-sized tentacles, sometimes branched on dorsal region of snout. Females usually with two small tentacles on each side of snout border. Evertible cheek plates supporting (14–26) hypertrophied odontodes (cheek spines). Eye mid-sized, 13.8–20.6% of HL, dorsal orbit not raised; dorsolaterally positioned. Interorbital region slightly concave. Exposed portion of opercle roughly triangular, supporting odontodes; supra-opercular region with few platelets near compound pterotic. Oral disk circular covered with small papillae; lower lip not reaching pectoral girdle, with papillae reducing in size toward margin; maxillary barbel short, attached to lip. Branchial opening small. Premaxillary and dentary tooth rows mid- to large; teeth short, thin, numerous, unicuspid ( Fig. 3b ), curved inward. Three specimens having tiniest lateral cusp, almost imperceptible (MUSM 11665, 2, 68.3–81.1 mm SL; MUSM 57732, 1, 59.6 mm SL). Only one small buccal papilla positioned between premaxillae. Head covered by dermal bones; dorsum covered by dermal plates, except at dorsal-fin base. Supraoccipital process limited posteriorly by first pair of predorsal plates and posterolaterally by the first plate of the mid-dorsal series. Trunk with five series of lateral plates, three lateral series on the narrowest portion of caudal peduncle. Mid-dorsal and mid-ventral series not surpassing adipose fin. Median series supporting lateral line. Short odontodes on fin rays and body plates. Ventral surface devoid of plates from snout tip to anal-fin insertion. Base of first anal-fin pterygiophore covered by skin. Dorsal-fin origin situated slightly anterior to vertical through pelvic-fin origin; dorsal fin usually reaching preadipose plate when adpressed; dorsal-fin spine flexible, shorter than head length. Adipose-fin spine short. Pectoral-fin spine inflexible and slightly curved inward, with hypertrophied odontodes and tentacles on its distal portion; pectoral fin surpassing pelvic-fin origin when adpressed. Pelvic fin flexible and curved inward, depressed pelvic-fin unbranched ray surpassing origin of anal fin. Anal fin short. Caudal-fin margin obliquely truncate with ventral unbranched ray longer than dorsal one. Fin-ray formula: dorsal II,7; pectoral I,6; pelvic i,5; anal i,4; caudal i,14,i. TABLE 2 | Morphometric and meristic data of Ancistrus maldonadoi . SD= standard deviation, N= number (including holotype).

Characters	Holotype	N	Range	Mean	SD
Standard length (mm)	114.7	21	61.6–147.2	80.9	-
Percents of standard length
Predorsal length	45.7	21	42.9–46.3	44.5	1.0
Head length	35.1	21	32.2–36.2	34.5	1.1
Occipital depth	19.1	21	16.4–19.1	17.6	0.7
Cleithral width	33.8	21	30.4–36.0	32.7	1.3
Dorsal-fin base length	20.3	21	18.4–21.3	19.8	0.9
Interdorsal length	19.9	21	17.9–23.8	20.4	1.6
Prepectoral length	29.2	21	25.8–30.0	28.3	1.1
Prepelvic length	51.5	21	48.9–53.5	50.4	1.1
Dorsal-fin spine length	25.3	21	24.1–27.6	26.0	1.0
Pectoral-fin spine length	29.2	21	25.2–30.5	26.6	1.4
First pelvic-fin ray length	25.9	21	22.6–27.6	25.4	1.2
Adipose-fin spine length	7.2	21	7.2–9.5	8.4	0.7
First anal-fin ray length	9.2	19	7.1–10.8	8.7	0.9
Thoracic length	25.0	21	24.4–27.6	25.9	0.9
Abdominal length	17.9	21	17.5–20.1	18.6	0.7
Upper caudal-fin ray length	26.1	13	24.1–30.3	27.9	1.8
Lower caudal-fin ray length	27.0	14	26.3–35.4	31.2	2.7
Caudal peduncle length	29.3	21	28.7–32.2	30.1	0.9
Caudal peduncle depth	13.1	21	12.2–14.0	12.7	0.4
Adipose-fin to caudal-fin length	13.5	21	13.4–17.7	15.3	1.3
Anal-fin to caudal-fin length	33.8	21	32.0–37.0	35.2	1.2
Percents of head length
Supracleithral width	86.3	21	78.0–92.7	85.1	3.3
Snout length	56.2	21	54.5–60.7	57.2	1.7
Interorbital distance	41.7	21	37.3–41.7	39.3	1.1
Orbital diameter	14.8	21	13.8–20.6	17.8	1.7
Occipital-orbital distance	41.7	21	39.4–43.2	41.4	1.2
Dentary width	26.7	21	25.9–31.4	27.9	1.4
Counts
Lateral median series	24	21	24–25	24.0	0.2
Dorsal-fin base	6	21	6–7	6.1	0.3
Between dorsal and adipose	8	21	6–8	7.2	0.5
Between adipose and caudal	6	21	5–7	5.8	0.5
Between anal and caudal	13	21	12–13	12.6	0.5
Preadipose plates	2	21	2–4	3.2	0.6
Premaxillary teeth	84	20	71–105	83.8	9.1
Dentary teeth	110	20	75–115	94.3	10.7
Cheek spines	26	21	14–26	19.0	3.3

Color in alcohol. Body background color yellowish-brown to greenish. Dorsal surface of head and trunk with rounded mid size spots, diameter similar or larger than pupil. Ventral surface of head and abdomen yellowish to light brown, brown on ventral surface of caudal peduncle. All fins with alternating dark and light spots on the rays, sometimes organized into transverse bands. Sexual dimorphism. Largest male and female with 114.7 mm and 147.2 mm SL, respectively. Mature males have small- to middle-sized tentacles on dorsal region and border of snout. Females sometimes with fewer and shorter tentacles than males limited to one series on lateral border of snout, usually two to four on each side of snout. FIGURE 5 | Partial map of Peru, showing the collecting sites of Ancistrus greeni ( yellow ) and Ancistrus maldonadoi ( white ). Star indicates type locality. Both symbols can represent more than one lot and/or locality. Geographical distribution. Ancistrus maldonadoi is only known from the río Madre de Dios and río Inambari basins ( Fig. 5 ). Etymology. The specific name maldonadoi is a special dedication in memoriam to professor Dr. Javier Maldonado-Ocampo , Pontificia Universidad Javeriana in Bogotá , Colombia for his great contribution to the Neotropical Ichthyology. Conservation status. Ancistrus maldonadoi occurs along a well-conserved region, with good water quality and little or no human pressure. Thus, considering the good environmental conditions of the known area of occurrence for the species, we suggest that A. maldonadoi be classified as LC (Least Concern) under the International Union for Conservation of Nature ( IUCN ) categories and criteria ( IUCN Standards and Petitions Subcommittee, 2019) of extinction risk.