Prodontocharax aquilaepinnae, Bertaco & Chuctaya & Jerep & Malabarba, 2023

Bertaco, Vinicius A., Chuctaya, Junior, Jerep, Fernando C. & Malabarba, Luiz R., 2023, Revision of Prodontocharax and revalidation of Amblystilbe (Teleostei: Characidae: Cheirodontinae), with description of a new species, Neotropical Ichthyology (e 230031) 21 (3), pp. 1-32 : 5-12

Prodontocharax aquilaepinnae , new species urn:lsid:zoobank.org:act:40A6E69F-55C9-43F0-B197-8B9F5D6438CE

( Figs. 1–3 ; Tab. 1)

Holotype. MUSM 38647 , 1 , 49.9 mm SL, male, Peru, Junín, Satipo, Río Tambo, Cubitiali stream, Río Huallaga basin, upper Río Amazonas basin, 11º20’19”S 73º31’25”W, 31 Jan 2010, J. Espino, E. Ríos, F. Cristobal & M. Pishirovanti.

Paratypes. Peru, Cusco: MUSM 69931 , 10 , 29.1–33.5 mm SL, Megantoni, Lote 58, Río Urubamba basin, Río Pagoreni , 11º44’04”S 73º13’09”W, 22 Sep 2021, F. Cari . Huánuco: ANSP 116450 , 20 of 50 (2 c&s), 31.3–51.9 mm SL, cueva de Pavos near Puente Perez, about 0.25 mi above Río Huallaga, vicinity Tingo Maria , 09º22’16”S 75º58’32”W, 30 Sep 1955, C. G. Chaplin & M. Hohn . ANSP 166928 , 10 , 33.0– 44.9 mm SL, Tingo Maria, 09º18’04”S 76º00’23”W, 1951, Servicio de Pesqueria . MUSM 14855 , 18 , 41.6 –62.0 mm SL, Tingo Maria, Río Huallaga, Las Pavas stream, 09º22’14”S 75º58’31”W, 12 Jul 1998, F. Chang & M. Velasquez . Junín: MUSM 38591 , 3 , 33.6– 51.9 mm SL, Satipo, Río Tambo, Río Mayapo , 11º15’31”S 73º33’46”W, 26 Jan 2010, J. Espino, E. Ríos, F. Cristobal & M. Pishirovanti . San Martín: MUSM 32661 , 7 , 38.3–46.9 mm SL, M. Caceres, Huicungo, Río Abiseo, Pepe stream, 07º24’05”S 76º52’03”W, 21 May 2008, H. Ortega . MUSM 54518 , 7 , 57.8–60.6 mm SL, Tocache, Uchiza, Huallaga , Río Huaynabez , Chuallaga , 08º19’48”S 76º16’19”W, 23 Nov 2006, F. Cari .

Non-type specimens. Peru, Cusco: MUSM 11979 , 77 , 32.9–49.1 mm SL, La Convención, Urubamba, Parotori stream, 11º59’48”S 73º07’39”W, 19 May 1997 , F. Chang. MUSM 18862 , 19 , 16.1–40.1 mm SL, La Convención, Echarate, Río Urubamba , 11º53’46”S 72º56’27”W, 2 May 2001 , E. Castro. MUSM 23063 , 2 , 38.5–44.8 mm SL, Quebrada Katchungari, Camana, alto Urubamba , 11º59’01”S 73º08’11”W, 26 Sep 2004 , H. Ortega et al. MUSM 30708 , 11 , 35.8–47.9 mm SL, Echarate, La Convención, Bajo Urubamba, Picha , katshigari stream, 11º59’00”S 73º08’13”W, 22 Jun 2004 , H. Ortega et al. MUSM 31168 , 4 , 30.5–42.2 mm SL, La Convención, Echarate, Bajo Urubamba, Picha , CN Camaná, Río Paratori , 11º59’16”S 73º08’09”W, 20 Jan 2005 , B. Rengijo et al. MUSM 31467 , 1 , 42.8 mm SL, La Convención, Echarate, Bajo Urubamba, Picha , CN Camaná, Katchingari , 11º59’09”S 73º07’53”W, 20 Jan 2005 , H. Ortega et al. MUSM 31838 , 1 , 32.4 mm SL, La Convención, Echarate, Bajo Urubamba, Picha , Alto Camisea , 11º49’49”S 72º34’25”W, 9 Oct 2007 , H. Ortega et al. MUSM 31892 , 26 , 31.8–33.7 mm SL, La convención, Echerate, Timpia , Río Timpia , 12º04’13”S 72º49’11”W, 15 Jan 2005 , H. Ortega. MUSM 34331 , 31 , 29.3–43.7 mm SL, La Convencion, Echarate , CN Camana, Alto Urubamba, Canchingari stream, 11º59’01”S 73º08’11”W, 29 Sep 2008 , I. Corahua et al. MUSM 36444 , 36 , 37.5–54.6 mm SL, La convención, Echarate , RC Matziguenga, 12º08’43”S 73º02’22”W, 12 Dec 2010 , J. Arana. MUSM 40092 , 4 , 36.2–46.9 mm SL, La Convención, Echarate , CN Nuevo Mundo, Bajo Urubamba, Río Huitiricaya , 11º30’07”S 73º15’13”W, 5 Jul 2010 , I. Sipión. MUSM 41576 , 1 , 28.5 mm SL, La Convención, Echerate, Río Camisea , 11º49’19”S 72º47’30”W, 27 Aug 2011 , I. Sipión. MUSM 45386 , 3 , 41.8–45.4 mm SL, La Convención, Megantoni, Porotobango, Kitepampanis , rio Urubamba , Huitiricaya stream, 11º27’38”S 73º18’44”W, 19 Jun 2017 , Sipion. MUSM 45409 , 2 , 44.3–44.5 mm SL, La Convención, Megantoni, Porotobango, Kitepampanis , Río Urubamba , Huitiricaya stream, 11º27’45”S 73º18’25”W, 21 Jun 2017 , I. Sipión. MUSM 45440 , 16 , 38.1–47.2 mm SL, La Convención, Megantoni, Porotobango, Nuevo Mundo , Urubamba , Río Huitiricaya , 11º30’04”S 73º15’15”W, 16 Jun 2017 , I. Sipión. MUSM 45567 , 29 , 31.3–47.6 mm SL, La Convención, Megantoni, Porotobango–Kitepampani, Urubamba , Río Huitiricaya , 11º27’42”S 73º18’51”W, 26 Sep 2017 , I. Sipión. MUSM 48043 , 1 , 55.5 mm SL, La Convención, Echerate, Cashiari, Tornillo stream, Río Urubamba , 11º51’47”S 72º43’27”W, 28 Jun 2013 , L. Santamaria. MUSM 48090 , 2 , 36.8–47.7 mm SL, La Convención, Echerate, Mipaya, Pitonari stream, rio Urubamba , 11º34’35”S 73º09’52”W, 25 Jun 2013 , L. Santamaria. MUSM 48161 , 2 , 45.5–46.7 mm SL, La Convención, Echerate, Mipaya, Pitonari stream, 11º34’19”S 73º10’10”W, 2 Jun 2013 , L. Santamaria. MUSM 49348 , 1 , 48.3 mm SL, La convención, Echarate, Sagari , Río Urubamba , Huitiricaya stream, 11º25’49”S 73º21’44”W, 9 Mar 2014 , V. Meza . MUSM 60459 , 17 , 27.6–48.7 mm SL, La Conveción, Megantoni, Urubamba, Río Pagoreni , 11º45’42”S 73º18’34”W, 8 Sep 2017 , R. Mejia . MUSM 63951 , 2 , 31.3–41.8 mm SL, La convención, Megantoni, Urubamba , Río Sensa , Porotobango , 11º24’27”S 73º21’42”W, 26 Mar 2018 , I. Sipion. MUSM 63997 , 4 , 32.0– 43.8 mm SL, La Convención, Megantoni, Urubamba , 11º27’36”S 73º18’58”W, 22 Mar 2018 , I. Sipión. MUSM 69015 , 1 , 44.2 mm SL, La Convención, Megantoni, Serjali, Río Serjali , unnamed stream, 11º45’19”S 72º29’47”W, 21 Oct 2019 , A. Mendoza. MUSM 66332 , 2 , 41.5–42.4 mm SL, La Convención, Megantoni, Cashiriari, rio Urubamba , 11º52’00”S 72º49’33”W, 21 May 2018 , I. Sipión. MUSM 67879 , 2 , 48.9–49.3 mm SL, La Convención, Megantoni, Río Urubamba, Las Pavas stream, 11º52’53”S 72º52’08”W, 20 May 2019 , L. Valenzuela et al. MUSM 69825 , 11 , 29.0– 35.6 mm SL, La Convención, Echarate, lote 88, Tsonkiri stream, Camisea , Urubamba , 11º47’42”S 72º50’17”W, 25 Sep 2021 , I. Sipion. MUSM 69864 , 1 , 46.2 mm SL, La convención, Echarate, lote 88, Tsonkiri stream, Camisea , Urubamba , 11º46’47”S 72º42’39”W, 20 Sep 2021 , I. Sipión. Junín: MUSM 37777 , 4 , 32.0– 49.9 mm SL, Satipo, Río Tambo basin, Mayapo stream, 11º22’27”S 73º29’58”W, 31 Jan 2005 , G. Trevejo & P. Zuñiga. MUSM 45728 , 4 , 45.9– 51.5 mm SL, Satipo, Río Tambo, Soroja , Río Mayapo , 11º22’13”S 73º29’58”W, 21 Sep 2017 , I. Sipión. MUSM 51100 , 6 , 32.7–49.6 mm SL, Satipo, Río Tambo , CN Mayapo, Ucayali, Mayapo stream, 11º22’27”S 73º29’58”W, 28 Jan 2010 , R. Olivera . MUSM 51182 , 27 , 32.5–52.1 mm SL, Junín, Satipo, Río Tambo , CCNN Mayapo, cuenca Río Ucayali, Mayapo stream, 11º22’10”S 73º30’00”W, 8 Jan 2010 , R. Olivera . MUSM 70320 , 1 , 42.6 mm SL, Satipo, Tambo, Santonano stream, 11º09’09”S 74º01’09”W, 16 Dec 2021 , D. Faustino. Huánuco: ANSP 168629 , 20 , 27.8–32.3 mm SL, Peru, Departamento de Huanuco, vicinity of Tingo Maria, back-water near Puerto Nuevo , flowing into Río Tullamayo , ca. 09º18’S 75º59’W, 649 m, 27 Sep 1955 , Catherwood Foundation Peruvian Amazon Expedition. MHNG 2725.025 , 1 of 2, 46.2 mm SL, Cueva de las Pasava, affluent of Río Huallaga , Tingo Maria , Leoncio Prado , 08º17’37”S 76º21’05”W, 14 Sep 2008 , S. Fisch-Muller, R. Covain , P. de Rham , V. Mesa Vargas, D. Ordonez & A. Minaya . MUSM 14898 , 64 , 27.0–40.0 mm SL, Tingo María, Huallaga , 09º18’00”S 76º00’00”W, 11 Jul 1998 , F. Chang & M. Velasquez. MUSM 28279 , 2 , 26.6–28.4 mm SL, Pto Inca, Río Pachitea, Río Sungaruyacu , 09º28’17”S 75º14’41”W, 11 Jul 2005 , V. Palacios & M. Rojas . MUSM 39311 , 3 , 41.7–45.2 mm SL, Leoncio Prado, Tingo Maria, Huallaga , Las pavas stream, 09º21’50”S 75º58’31”W, 19 Sep 2008 , H. Ortega et al. Loreto: MUSM 15886 , 3 , 41.7–44.9 mm SL, Ucayali, Rashaya, Vibra Caño , 07º58’04”S 75º24’00”W, 17 May 1997 , M. Hidalgo. MUSM 15907 , 5 , 36.5–42.3 mm SL, Río Ucayali, Rashaya, Norte stream, 07º58’04”S 75º24’00”W, 16 May 1997 , M. Hidalgo. San Martín: MHNG 2725.024 , 4 of 9, 50.8–60.6 mm SL, Río Cachiyacu, affluent of Río Huallaga, versant Chapaja , Chapaja , Tocache , 08º17’37”S 76º21’05”W, 14 Nov 2008 , S. Fisch-Muller & A. Minaya. MUSM 15642 , 3 , 46.9–55.4 mm SL, Tarapoto, Morales, San Antonio , Río Cumbaza , 06º32’08”S 76º21’54”W, 18 Sep 1998 , Guerra et al. MUSM 67361 , 10 , 27.4–34.7 mm SL, Mariscal Cáceres, Pajarillo, Amazonas , Huallaga , 07º10’55”S 76º41’46”W, 23 Jun 2019 , R. Quispe et al. Ucayali : MUSM 35790 , 2 , 43.3–46.3 mm SL, Padre Abad, Aguaytia, Ucayali, Río Aguaytia , Río Shambo , Tigre stream, 08º54’49”S 75º38’24”W, 12 Aug 2009 , R. Oliveira & G. Quezada . MUSM 47702 , 1 , 40.9 mm SL, Atalaya, Reymondi, quebrada Coconal , affluent of Río Urubamba , 10º41’02”S 73º07’31”W, 21 Mar 2013 , R. Olivera . MUSM 59300 , 4 , 44.8–49.3 mm SL, Padre Abad, Aguaytia, Ucayali, Río Aguaytia , 09º02’24”S 75º30’10”W, 17 Oct 2016 , F. Peñaloza.

Diagnosis. Prodontocharax aquilaepinnae is distinguished from P. melanotus by the anal fin pigmented along the base to median portion of second to seventh branched rays (vs. not pigmented); by the number of olfactory organ lamellae, with 32 in males and 24 in females (vs. 40–42 in males and 30–32 in females), and by the number of gill-rakers on upper limb (10–11 vs. 13).

Description. Morphometric data summarized in Tab. 1. Largest male 49.9 mm SL, largest female 51.9 mm SL. Body elongated and compressed, with greatest body depth near dorsal-fin origin. Dorsal body profile slightly convex from nostril to dorsal-fin origin, slightly or strongly concave at supraoccipital; posteroventrally slanted at dorsal-fin base; nearly straight from last dorsal-fin ray to caudal peduncle. Ventral head profile nearly straight. Ventral body profile deeply convex from pectoral-fin origin to pelvic-fin origin, and nearly straight to anal-fin origin. Anal-fin base nearly straight. Caudal peduncle very elongate, nearly straight to slightly concave in the dorsal and ventral margins.

Head relatively small. Snout rounded from margin of upper lip to vertical through anterior nostrils. Mouth distinctly inferior, mouth slit at horizontal through inferior border of eye. Maxilla very short. Obliquely positioned maxilla ending at vertical near or at anterior border of eye and at horizontal on inferior eye border. Premaxilla with 5 teeth tricuspid, central cusp longer and broader than lateral cusps; distal margin of teeth arched (n = 2). Maxilla with 4 to 5 teeth tricuspid, rarely conical (n = 2). Dentary with 6 to 8 teeth; anterior 6 teeth large and tricuspid, followed posteriorly by 2 teeth conical and small (n = 2). Anterior 5 to 6 dentary teeth inserted at the anterior and anterolateral border of bone and radially projected to anterior and lateral borders of the mouth; dentary teeth main axis positioned horizontally (n = 2). All cusp tips slightly curved inside the mouth ( Fig. 2 ). Olfactory rosette slightly oval with 24(2) lamellae in females, and 32(2) lamellae in males around of central median raphe ( Fig. 3 ).

Dorsal-fin rays ii,9* (n = 27); first unbranched ray approximately half length of second ray. Dorsal-fin origin slightly behind to vertical line projected through pelvic-fin origin. Adipose-fin located just posterior to vertical through posteriormost anal-fin ray insertion. Anal fin rays ii–iv,12–14 (iv,15*, mean = 13, n = 27). First unbranched ray normally only apparent in c&s specimens. Anal-fin origin posterior to vertical line projected through base of last dorsal-fin rays. Pectoral-fin rays i,10–11* (n = 27). Pectoral fin not reaching pelvic-fin origin in both sexes. Pelvic-fin rays i,6,i* (n = 27). Pelvic-fin origin anterior to a vertical line projected through dorsal-fin origin. Caudal fin forked, with 19* principal rays (n = 27); lobes similar in size. Dorsal procurrent rays 11–12, and ventral procurrent rays 9–11 (n = 2).

Scales cycloid, moderately large. Lateral line complete. Scales in longitudinal series 35–37 (36*, mean = 35.4, n = 18). Scale rows between dorsal-fin origin and lateral line 5–6* (mean = 5.4, n = 20); scale rows between lateral line and pelvic-fin origin 4* (n = 20). Predorsal scales 10–12* arranged in regular series (mean = 11, n = 18). Scales rows around caudal peduncle 14* (n = 20). No modified scales on caudal-fin. Scale sheath along anal-fin base formed of 4–5 scales in single series, extending to base of fourth to fifth branched rays.

Precaudal vertebrae 17; caudal vertebrae 17–18; total vertebrae 34–35. Supraneurals 5 (n = 2). Gill-rakers of first gill arch 10–11 on upper limb and 17 (n = 2) on lower limb.

Coloration in alcohol. General ground body color brownish or yellowish. Scales near dorsal midline clearly delineated with dark chromatophores. Scales on lateral surface of body weakly pigmented, if at all. Dark unpigmented triangular area at pseudotympanum. Narrow midlateral body stripe extending from vertical line through near dorsal-fin origin to caudal-fin base, weakly pigmented at base of median caudal-fin rays, forming small black spot. Dorsal fin with densely pigmented dark spot between median portion of third to seventh branched rays. Anal fin pigmented along base to median portion of second to seventh branched rays. Adipose fin not pigmented ( Fig. 1 ).

Sexual dimorphism. Males of Prodontocharax aquilaepinnae are easily recognized by the presence of bony hooks on anal and pelvic-fin rays and by anal-fin profile, nearly straight in males, and smoothly concave in females. Branched anal-fin ray length decreasing gradually from first to last rays in males, and length of branched anal-fin ray decreasing rapidly from first to fourth or fifth rays and gradually decreasing in remaining rays in females. Anal-fin rays of males bearing one pair of retrorse bony hooks per segment of lepidotrichia along posterolateral border. Hooks usually in last unbranched ray and along anterior nine branched rays, rarely through tenth ray, more numerous along second through fourth rays. Hooks located along posteriormost branch of branched ray, and two thirds to half distal length of ray. Tip of pelvic fin reaching urogenital opening in females, and reaching or close to anal-fin origin in males. Pelvic fin of males bearing usually one, rarely two, retrorse and short bony hooks per segment of lepidotrichia, along posteriormost branch of all branched rays, rarely found in anteriormost branches. Hooks distributed along ventromedial border and usually more than 2/3 of distal length of each ray. Males and females also slightly differ in the relative pelvic-fin length (larger in males than females, Tab. 1). The number of lamellae in olfactory rosette is greater in males than in females (32 and 24–26, respectively). Nonhistological examination of the first gill arch of a male (ANSP 116450, 46.7 mm SL) shows the anterior five filaments of the lower branch of the first gill arch apparently fused in a gill organ.

Geographical distribution. Prodontocharax aquilaepinnae is known from the Huallaga,

Ucayali, and Urubamba river basins, upper Amazonas River basin, Peru ( Fig. 4 ).

Ecological notes. The holotype of Prodontocharax aquilaepinnae was collected in the Cubiriali stream, Tambo River basin. This stream is 6 m wide and 1 m deep. It presents moderate water velocity, clear water with greenish coloration. The bottom substrate characterized by stones and gravel and with the margins covered by vegetation ( Fig. 5 ).

Etymology. The name aquilaepinnae is from the Latin, aquiluus, blackish or dark- colored, and pinnae, fins, referring to the pigmented dorsal and anal fins. A noun in adjective.

Conservation status. No significant threats were identified for the Prodontocharax aquilaepinnae , which is suggested to be categorized as Least Concern (LC), according to IUCN criteria ( IUCN, 2022).

Figures

FIGURE 1 | Prodontocharax aquilaepinnae, Peru, Junín, Satipo, Tambo River, Huallaga River basin, upper Amazonas River basin; A. MUSM 38647, holotype, male, 49.9 mm SL, Cubitiali stream; B. MUSM 38591, paratype, female, 51.9 mm SL, Mayapo River. Photos: Dario F. Fuster and Junior Chuctaya.

FIGURE 2 | Prodontocharax aquilaepinnae, ANSP 116450, 47.6 mm SL, paratype. Scanning electronic microscopy (SEM) image of left side upper and lower jaws teeth.A. Premaxilla.B. Maxilla; arrow indicates the twisted posterior edentulous portion of the maxilla. C. Dentary; arrow indicates the separation of an anterior large tooth series angled and discontinuous with the posterior small tooth series.

FIGURE 3 | Lamellae of central median raphe of olfactory rosette of Prodontocharax aquilaepinnae, MUSM 14855, paratypes, male, 43.8 mm SL (left), female, 52.1 mm SL (right), Peru, Huánuco, Tingo Maria, Huallaga River, Las Pavas stream. Photos: Junior Chuctaya.

FIGURE 4 | Map of central and northern South America showing the distribution of Amblystilbe howesi (red dots), Prodontocharax melanotus (yellow dots) and P. aquilaepinnae (gray dots). Some symbols represent more than one lot or locality. Stars represent the type localities. Red triangle represents the type-locality of P. alleni.

FIGURE 5 | Type-locality of Prodontocharax aquilaepinnae, Cubiriali stream, Tambo River basin, Huallaga River basin, Junín, Peru. Photo: Jessica Espino.