Ancistrus maldonadoi, Bifi & Ortega, 2020

Bifi, Alessandro Gasparetto & Ortega, Hernán, 2020, Redescription of Ancistrus greeni (Siluriformes: Loricariidae), and description of a new species from the río Madre de Dios basin, Peru, Neotropical Ichthyology (Neotrop. Ichthyol.) 18 (1), No. e 190070, pp. 1-18 : 8-12

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 .

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.

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.

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.

Figures

FIGURE 3 | Details of the teeth showing lack of lateral cusp in A. Ancistrus greeni and B. Ancistrus maldonadoi. Bars = 0.1mm.

FIGURE 4 | Ancistrus maldonadoi, MUSM 57733, holotype, 114.7 mm SL, male, Peru, Manu, río Madre de Dios basin, río Salvación.

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.