Hypoptopoma machadoi, Aquino, Adriana E., 2010

Aquino, Adriana E., 2010, Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae), Bulletin of the American Museum of Natural History 2010 (336), pp. 1-110 : 89-94

Hypoptopoma machadoi , new species Figure 44 , table 17

HOLOTYPE: MBUCV V-35362 (♀, 46.2 mm SL) Venezuela: San Fernando de Apure, swamps on south bank of Río Apure, ca. 3 km west of Fisheries Station ; collected by Apure Fisheries Station technicians, 21 January 1983.

PARATYPES: AMNH 77794, 23 females, 42.1–53.7 mm SL (collected with holotype).

OTHER MATERIAL EXAMINED: COLOM- BIA, Meta: ANSP 128569 (1 ³, 48.3 mm SL) Hacienda Mozambique, N. shore at main house ; ANSP 128955 (9 ♀ + 3 ³, 45.8–61.7 mm SL) Río Negro, just downstream from where it passes under the main Villavicencio, Puerto López highway at La Balsa (W side of river) ; ANSP 128956 (6 ♀ + 3 ³, 50.4–69.3 mm SL) Río Negrito midway between La Argelia and La Balsa (Plancha 267 – Río Guayuriba ) ; ANSP 128960 (16 ♀ + 2 ³, 47.5–66.5 mm SL) Río Negro, just downstream from where it passes under the main Villavicencio, Puerto López highway at La Balsa ; ANSP 131666 (5 ♀ + 1 ³, 45.6– 61.9 mm SL) Río Negrito downstream bridge at La Balsa ; ANSP 134438 (18 ♀ + 3 ³, 2 cs, 39.8–53.2 mm SL) tributary caño La Raya (first caño N de La Siberia) ; ANSP 139463 (3 juveniles, 25.5–31.0 mm SL) canal y laguna Aerotas, S. side of Río Metica, entrance on Metica, ca. 2 km. SW (upstream) of entrance to Lake Mozambique ; FMNH 84005 (1 ³ + 2 juveniles, 24.3–51.3 mm SL) Caño Venturosa, at 1 km N Puerto López. VENEZUELA, Amazonas: MCNG 6306 (4 ♀, 43.7–59.7 mm SL). Anzoátegui: ANSP 166734 (2 ♀, 54.9– 57.8 mm SL) Río Orinoco basin, Soledad, L. Terecaya. Apure: ANSP 130028 (1 ♀, 41.7 mm SL) Camaguán swamp, on W side of Hwy to San Fernando de Apure , about 2 km N of Camaguán ; ANSP 130040 (12 ♀, 1 cs; 38.2–50.5 mm SL) S bank and backwater areas pm downstream side of bridge at San Fernando de Apure ; ANSP 165843 (4 ♀ + 3 ³, 53.6–69.0 mm SL) Río Cunaviche, ca. 20 km SW of Cunaviche on San Fernando de Apure – Puerto Paez Hwy ; ANSP 165844 (1 ♀, 38.8 mm SL) Río Matiyure, at Achaguas ; ANSP 166433 (2 ♀, 31.4–44.9 mm SL) Caño Caicara , 10–12 km W of Montecal ; CAS 64271 (3 ♀, 44.0– 58.1 mm SL) pool just S of Bruzual alongside dyke that parallels highway behind bull run ; CAS 64283 (59 ♀ + 4 ³, 35.6–62.2 mm SL) Caño first creek S of Bruzual at red steel bridge ; FMNH 85814 (35 ♀ + 3 ³, 33.9–53.4 mm SL) River 24 km S Biruaca on road to San Juan de Apayara ; FMNH 85826 (10 ♀ + 1 ³, 31.2–47.2 mm SL) Río Aruaca, 32.5 Km S Biruaca ; INHS 29809 (13 ♀, 40.7–53.2 mm SL) tributary caño Setento , 10 km. S Bruzual ; INHS 30098 (34 ♀, 27.9–45.4 mm SL) Caño Guaritico (5 caño Maporal) ( Río Apure drainage), 58 km SSW Bruzual ; MCNG 6104 (7 ♀, 37.1– 44.3 mm SL) ; MCNG 9369 (8 ♀ + 4 ³, 42.5–49.3 mm SL) ; MZUSP 27973 (51 ♀, 32.3–51.0 mm SL) caño 1 km ao sul passagem de balsa, na altura da estrada de San Fernando de Apure ; USNM 257971 (2 ♀, 43.3–44.2 mm SL) Río Apure West of town center ; USNM 257972 (68 ♀ + 1 ³, 35.1–49.7 mm SL) Caño Caicará, where crossed by bridge on road from Montecal ; USNM 257975 (2 ♀, 46.8–50.6 mm SL) Río Apure ca. 2 km East of bridge at San Fernando de Apure ; USNM 260193 (52 ♀ + 2 ³, 32.7–66.1 mm SL) side channel of Río Apure ca. 5 km West of San Fernando de Apure. Barinas: FMNH 105985 (2 ♀, 36.7– 42.9 mm SL) Río Suripa ca. 10 min. by boat above confluence with Río Carapo ; FMNH 105986 (1 ♀, 62.5 mm SL) Río Anaro ca. 10 min. from mouth in Río Suripa , small island and collected small arms of river ; FMNH 105987 (27 ♀ + 4 juveniles, 30.7– 49.2 mm SL) Caño La Indiecita near mouth

TABLE 17 Morphometric and Meristic Data for Hypoptopoma machadoi Holotype: MBUCV V-35362. Paratype: AMMH 77794. Nontypes: ANSP 165843 ; CAS 64283 ; FMNH 85814 , 85826 ; LACM 43204-4 ; MCNG 9369 .

in Río Suripa ca. 35 min. up river from boat launch in Hato Mercedes ; FMNH 105988 (3 ♀, 42.7–48.1 mm SL) Caño Socopo ca. 3.5 hours upstream from boat launch of Hato Mercedes in Río Suripa .; FMNH 108762 (1 ♀, 48.3 mm SL) Río Orinoco drainage, Caño Caigua ca. 20 min. by boat from boat launch at Hato Las Mercedes ; INHS 28696 (20 ♀, 47.1–56.0 mm SL) Río Santo Domingo ( Río Apure drainage) in Torunos, hacienda La Isla ; MCNG 21329 (7 ♀, 42.2–53.3 mm SL) ; MCNG 26277 (6 ♀ + 1 ³, 41.9–55.9 mm SL). Bolívar : ANSP 135631 (11 ♀ + 7 ³, 42.1–63.1 mm SL) Caño Chuapo ca. 20 min. downstream from Jabillal (opposite bank) on Río Caura ; ANSP 135678 (20 ♀ + 1 ³, 36.8–57.1 mm SL) mouth of caño Chuapo ca. 20 min. downstream from Javillal (opposite bank) on Río Caura ; ANSP 139521 (1 ♀, 39.9 mm SL) Quebrada Cuchivero (Cuchiverito), tributary of Río Mato (right bank) ; ANSP 139620 (12 ♀ + 1 ³, 40.0– 61.2 mm SL) Sandbar along Río Mato ; ANSP 160863 (1 ♀, 42.2 mm SL) Río Cuchivero at Cuchivero ferry crossing ; FMNH 97050 (1 ♀, 40.8 mm SL) Río Orinoco , cove West end of islote Fejardo, 182 naut. mi. upstream from sea buoy ; FMNH 108767 (1 ♀, 43.4 mm SL) Río Orinoco basin, S bank of Río Orinoco at mouth of Río Orocopiche, in mouth and along Orinoco ; FMNH 108768 (4 ♀, 38.2– 55.0 m SL) Río Orinoco basin, Río Orinoco just above bridge at Ciudad Bolívar ; MCNG 6658 (3 ♀ + 1 ³, 47.4–70.8 mm SL) ; SU 48664 (9 ♀ + 1 ³, 40.6–48.9 mm SL) Río Orinoco at Caicará ; USNM 265696 (1 ♀, 41.5 mm SL) Río Orinoco , Cove, Islote de Fajardo, 182 naut. mi. upstream from sea buoy ; USNM 265963 (1 ♀, 47.6 mm SL) small caño connecting with Río Orinoco immediately South of El Burro. Cojedes : MCNG 13770 (1 ♀ + 6 juveniles, 20.6– 45.0 mm SL). Delta Amacuro : AMNH 47955 (6 ♀, 38.6–48.0 mm SL) lagoon at caño Araguaíto , ca. Km 130, Río Orinoco ; ANSP 152860 (9 ♀, 1 cs, 36.7–47.1 mm SL) ca. Km. 65, small caño near mouth of caño Fiscal, Río Orinoco ; FMNH 97051 (1 ♀, 36.3 mm SL) backwater caño Araguao , 112 naut. mi. upstream from sea buoy ; FMNH 97052 (4 ♀, 44.4–49.7 mm SL) Río Orinoco , cave on sand bar near E end of Isla Portuguesa, 117 naut. mi. upstream from sea buoy ; FMNH 97066 (14 ♀, 37.9–53.5 mm SL) Río Orinoco , first small caño on W side of caño Paloma 100 m above its mouth, 92 naut. mi. upstream from sea buoy ; FMNH 108765 (1 ♀, 43.4 mm SL) Río Orinoco at plays on North side ; FMNH 108766 (2 ♀, 44.7–48.3 mm SL) Río Santa Clara at first tributary on East side ca. 0.5 hour above mouth ; LACM 43016-2 (1 ♀, 48.2 mm SL) N bank – beach across from Los Castillos ; 160 NM upstream from sea buoy; LACM 43151-16 (69 ♀ + 1 ³, 32.9– 54.1 mm SL) Río Orinoco , inlet ; 82 NM upstream from sea buoy; LACM 43204-4 (30 ♀ + 3 ³, 35.2–66.8 mm SL) Río Orinoco , shallow lagoon on N side of river, W of caño Araguarito ; LACM 43297-2 (15 ♀ + 1 juvenile, 25.3–46.5 mm SL) Teda , caño Paloma system ; USNM 265682 (1 ♀, 44.3 mm SL) Río Orinoco , first small caño on W side of caño Paloma 100 m above its mouth, 92 naut. mi. upstream of sea buoy ; USNM 265708 (5 ♀, 38.3–50.6 mm SL) Río Orinoco , small caño near mouth of caño Socoroco , 111 naut. mi. upstream from sea buoy. Guárico: ANSP 166732 (19 ♀, 38.9– 48.8 mm SL) Río Orinoco basin, Cabruta, Laguna Larga II ; ANSP 166733 (1 ♀ + 1 ³, 37.4–62.7 mm SL) Río Orinoco basin, Cabruta, Laguna Larga II ; FMNH 85807 (1 ♀, 39.9 mm SL) pond by river at 8 km E of Camaguán on road to Uvenito ; INHS 62063 (43 ♀, 33.9–47.1 mm SL) caño ( Río Guariquito–Río Orinoco drainage) 100 air km E San Fernando ; MCNG 15072 (10 ♀, 37.8– 48.7 mm SL) ; USNM 257969 (7 ♀, 32.8– 43.4 mm SL) Caño Falcon ca. 5 km north of RPV 83-4 ; Río Portuguesa drainage basin ; USNM 257973 (16 ♀, 36.2–48.3 mm SL) Caño to West of highway from Calabozo to San Fernando about 35 km South of Fundo Masaguaral, Caño Falcon ; USNM 257976 (1 ♀, 45.6 mm SL) Río Guárico at Flores, Moradas ranch ca. 3–4 km East of road from Calabozo to San Fernando. Monagas : CAS 58157 (5 ♀, 47.0– 54.8 mm SL) Río Orinoco , small caño 0.75 miles upstream from mouth of caño Guarguapo, near Barrancas ; LACM 43382-29 (7 ♀, 43.0– 54.9 mm SL) Río Orinoco , secondary caño about 500 m from its mouth in caño Guarguapo ; LACM 43423- 4 (31 ♀ + 1 ³, 35.1–50.7 mm SL) Río Orinoco, S shore of Isla Noina , 51–52 NM from sea buoy ; USNM 163172 (1 ♀, 53.0 mm SL) Caicará , Río Guarapiche ; USNM 265718 (17 ♀, 3 cs, 36.3–48.3 mm SL) Río Orinoco , 161 naut. mi. upstream from sea buoy, laguna Tapatapa on Isla Tapatapa near downstream end of caño de Limón. Portuguesa: MCNG 1179 (4 ♀ + 3 ³, 39.0– 55.5 mm SL) ; TNHC 12513 (6, 43.6–53.3 mm SL) Caño Maraca at Urriolas ranch, 35 km SE Guanare´ ; TNHC 12766 (10 ♀, 35.6– 39.8 mm SL) Caño Maraca at Urriolas ranch, 35 km SE Guanare´ ; USNM 348681 (12 ♀, 38.2–57.8 mm SL) Guanaré-Guanarito , road at road km 60 ; caño Igues–Río Portuguesa (Caño Maraca) .

DIAGNOSIS: Hypoptopoma machadoi is distinguished from all congeners, with the exception of H. gulare , by the presence of a single paranasal plate separating the lateral process of the lateral ethmoid from the second infraorbital and the nasal organ (fig. 7B). In contrast, in all other species of Hypoptopoma , except H. steindachneri , the paranasal plates are absent and the lateral process of the lateral ethmoid contacts the second infraorbital (fig. 7A). In H. steindachneri , there are two or more paranasal plates (fig. 7C).

Hypoptopoma machadoi is distinguished from H. gulare by its deeper caudal peduncle (caudal-peduncle depth 9.0–12.0 (10.2) vs. 7.2–9.1 (8.7); t (16.298), p, 0.001); by its greater number of premaxillary (16–25 (20) vs. 12–16 (14); t (16.298), p, 0.001) and dentary teeth (14–21 (17) vs. 10–14 (12); t, p, 0.001); by having lanceolate plates at caudal-fin base with light brown spot, symmetrically shaped, shortly extended over branched rays; spot followed by three vertical bands variably defined, with anterior band not continuous along midline with the basal spot (vs. lanceolate plates at caudal-fin base with dark spot, asymmetrically shaped, slightly more extended over lower-lobe branched rays; this spot is followed by two V-shaped bars, anterior bar variably developed on the upper lobe but always connected with basal spot) (fig. 17B); and by having the dorsal fin with typically three bars, without triangular spot at base (vs. dorsal fin with roughly triangular dark brown spot extended over base of anterior 3–4 branched rays, followed typically by 3–4 bars) (fig. 17G).

Hypoptopoma machadoi is distinguished from H. steindachneri by having a single paranasal plate (vs. presence of two or more paranasal plates) (fig. 7B–C), second infraorbital in contact with nasal and pararostral plates (vs. second infraorbital entirely separated from nasal and pararostral plates), and ventral canal-bearing plate undivided (vs. canal-bearing plate typically subdivided) (fig. 5A–B).

DESCRIPTION: Morphometric and meristic data presented in table 17. Body robust; greatest body depth at dorsal-fin origin. Dorsal profile of head and body straight from tip of snout to dorsal-fin origin, slightly angled dorsally at posterior tip of supraoccipital; straight from dorsal-fin origin to anteriormost procurrent caudal-fin ray. Head moderately depressed, almost as wide as cleithral width; lateral process of lateral ethmoid bone visible dorsally. Snout rounded in dorsal view; dorsally, slightly concave anterior to naris. Posterior surface of bony pit of nasal organ sharply inclined. Trunk cross section between pectoral-fin and pelvicfin origins slightly triangular, ovoid to progressively rounded posterior to dorsal fin, progressively compressed posterior to adipose-fin base.

Eyes relatively large, positioned closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located on ventral surface of head. Dorsal interorbital distance/ventral interorbital distance ratio changing from,1 to.1 during ontogeny.

(12,068)

Total plates in lateral medial series typically 21–22 (22). Dorsal series plates 18–19 (19); middorsal series plates 3–4 (4); midventral series plates 12–13 (13), three plates anterior to first ventral series plate; ventral series plates 18–19 (19). Second plate of midventral series contacting two plates of medial series.

Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right series, 3–10 each; anterior azygous plate usually present; medial series of plates, if present (47 % of 316 individuals examined), not forming well-defined series. Single anal plate present. Thoracic plates present, 2–6. Preopercular canal present, semicircular; anteriormost pore located between ventral canal-bearing plate and fourth infraorbital; posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital variably developed, framed by notch at posterolateral margin of canal-bearing plate and ventral margin of fourth infraorbital.

Small odontodes evenly distributed on head. Odontodes along rostral margin of snout not arranged in well-defined series, without odontode-free discontinuity between ventrad and dorsad odontodes. Odontodes dorsal to tip of snout small, slightly larger than those on dorsal surface of head. Lamina of trunk plates with odontodes arranged in longitudinal rows, becoming progressively smoother ontogenetically; marginal odontodes present in mature adults.

Total vertebrae 26. Premaxillary teeth 16– 25 (20); dentary teeth 14–21 (17). Maxillary barbels short; in adults, slightly surpassing anterior margin of ventral canal-bearing plate.

Dorsal-fin origin located slightly posterior to vertical through pelvic-fin origin. Depressed dorsal fin reaching to vertical through distal half of anal-fin base. Pectoral fin reaching to vertical through midpoint between anus and anal-fin origin. Pectoral spine with serrae along posterior margin, individual serrae oriented orthogonal to spine shaft. Extension of serrae along pectoral spine margin reduced ontogenetically from proximal two-thirds in smaller specimens to middle third in larger specimens. Depressed pelvic fin not reaching to anal-fin origin; unbranched and first branched rays of equal length. Caudal-fin margin concave; upper and lower lobes equal. Adipose fin present.

COLOR IN ALCOHOL: Ground color tan and light brown. Melanophores light to dark brown, clustered on trunk and at base of plates, yielding mottled appearance. Pigmentation slightly more concentrated dorsally on head, along narrow area betweeen compound pterotic, cleithral process and opercle, at base of dorsal and pectoral fins, and on anterior surface of lip. Deep-lying melanophores arranged as series of blotches posterior to dorsal-fin base. Midlateral stripe mostly along trunk medial series of plates. Ventral surface of body mostly unpigmented except for scattered melanophores on posterior portion of trunk, anterolateral margin of cleithra and posterior tip of cleithral process, lateral border of canal-bearing plates, and lateral portions of lateral abdominal series. Paired dorsal and anal fins with dark brown bars, aligned roughly orthogonal to the rays. Basal dark spot on anterior dorsal-fin branched rays typically not developed; if present, spot poorly defined. Lanceolate plates at base of caudal fin with light brown spot, symmetrically shaped and shortly extended over branched rays, followed by typically three vertical bands variably defined, with anterior one not continuous in the middle with basal spot; tips of lobes variably pigmented (fig. 17G).

SEXUAL DIMORPHISM: Males with genital papilla small, not clearly separated from tubelike anal papilla. Males without patch (or patch poorly developed) of tightly arranged small odontodes oriented as a swirl on plates lateral to anal region. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes.

DISTRIBUTION: Known for the Rio Orinoco basin in Venezuela, including the Rio Meta drainage in Colombia (fig. 39).

REMARKS: Specimens collected in the Río Meta drainage and in localities along the southern tributaries of the Río Orinoco are slightly more slender and with fewer caudalfin bars than specimens that originated in localities from northern tributaries to the Río Orinoco.

ETYMOLOGY: The specific epithet machadoi is a patronymic honoring Antonio Machado-Allison, in recognition of his lifelong dedication and contributions to Neotropical ichthyology.

PHYLOGENETIC ANALYSIS Character Descriptions and Coding

Figures

Fig. 44. Hypoptopoma machadoi, paratype, AMNH 77794, 46.2 mm SL female, in dorsal, lateral, and ventral views.