Ancistrus patronus, De & Taphorn & Armbruster, 2019

De, Lesley S., Taphorn, Donald C. & Armbruster, Jonathan W., 2019, Review of Ancistrus (Siluriformes: Loricariidae) from the northwestern Guiana Shield, Orinoco Andes, and adjacent basins with description of six new species, Zootaxa 4552 (1), pp. 1-67 : 39-43

Ancistrus patronus , new species

( Figs. 19–20 )

Holotype. MCNG 56681 (ex AUM 39876) (1, 83.6 mm SL), male, Venezuela, Amazonas, Orinoco River Basin, Ventuari River at mouth of Camoni creek , 145 km NNE of Macaruco, 189 km NE of San Fernando de Atabapo, 5.05588, -66.32742, 8-Apr-2004, M. Sabaj, N. Lujan, D. Werneke, L. de Souza, and O. León.

Paratypes. All from Venezuela, Orinoco River Basin: Amazonas State: ANSP 160236 (1, 74.3 mm SL), creek 15 km E Parguaza River ferry crossing on Caicara-Puerto Ayacucho hwy, 6.35946, -67.05375, 28-Nov-1985, B. Chernoff, W. Saul, C. Marrero, R. Royero ; AUM 39271 (6, 5, 50.8–86.0 mm SL), Parucito River, at raudales Salomon, 2.7 km NE of San Juan de Manapiare, Ventuari / Manapiare drainage, 5.34637, -66.03347, 16 April 2004, D. Werneke, N. Lujan, O León-Mata; ANSP 205667 (4, 57.9–75.7 mm SL); AUM 39306 (7, 5, 62.4–86.0 mm SL), Manapiare River 14.5 km NW of San Juan de Manapiare, Ventuari River drainage, 5.42863 -66.13616, 12-Apr- 2004, N. Lujan, M. Sabaj, L. de Souza, D. Werneke ; AUM 39876 (4, not measured), same data as holotype; ANSP 205668 (3, 60.3–66.8 mm SL); AUM 40189 (6, 1, 60.1 mm SL), tributary to Orinoco River , 30 km S of Puerto Ayacucho, 5.38659, -67.61556, 1-Apr-2004, D. Werneke, N. Lujan, L. de Souza, O. Leon Mata, M. Sabaj ; AUM 40578 (1, 74.7 mm SL), Orinoco River at Macuruco landing, 3.95816, -067.03231, 4-Apr-2004, M. Sabaj, L. de Souza, D. Werneke, N. Lujan ; AUM 41324 (2, 1, 77.9 mm SL), Manapiare River 14 km NW San Juan de Manapiare, 5.43704, -66.11408, 13-Apr-2004, M. Sabaj, N. Lujan, D. Werneke, L. de Souza ; AUM 41494 (1, 71.3 mm SL), Ventuari River drainage, Manapiare River at mouth of Yutaje creek , 14 km NW of San Juan de Manapiare, 5.43667, -66.11261, 11 Apr-2004, M. Sabaj, L. de Souza, D. Werneke, N. Lujan ; AUM 42176 (1, 71.5 mm SL), Casiquiare River drainage, Siapa River at rapids, 154 km E of San Carlos de Rio Negro, 1.60339, - 65.71587, 11-Mar-2005, M. Sabaj, L. de Souza, D. Werneke, N. Lujan ; AUM 43572 (3, 2, 52.3–65.1 mm SL), Casiquiare / Siapa River drainage, Guama creek draining Cerro Derecha , 16-Mar-2005, N. Lujan, D. Werneke, M. Sabaj, M. Arce-Hernández, R. Betancur ; AUM 43868 (1, 79.4 mm SL), Caño Soromoni , 11.8 km E of La Esmeralda, 3.19380, -65.65197, 26-Mar-2005, N. Lujan, M. Arce-Hernández, L. Richmond, B. Grant, E. Wesley ; AUM 53894 (1, not measured), Parucito River at raudales Solomon, Manapiare River , Ventuari River drainage, 5.34648, -66.03328, V. Meza, O. Santaella, and N. Lujan , 11-Apr-2010 ; AUM 54088 (1, not measured), Ventuari River, cobble shoal ~ 1 km upstream of Moriche, 167 km ENE of San Fernando de Atabapo, 4.75346, -66.37260, N. Lujan, D. Werneke, M. Sabaj, T. Carvalho, O. Leon , V. Meza , 3-Apr-2010 ; AUM 54420 (1, not measured), Manapiare River at Manapiare landing, 173.8 KM ESE of Puerto Ayacucho, Ventuari River drainage, 5.32864, - 66.05067, J. Birindelli, O. Léon , 13-Apr-2010 ; AUM 54313 (1, not measured), Marueta creek, 159 km E of San Fernando de Arabapo, 4.29481, -66.28888, N. Lujan, M. Sabaj, D. Werneke, T. Carvalho , V. Meza , 2-Apr-2010. INHS 61554 (3, 58.2–79.6 mm SL), stream near Pozo Azul , 5.763219, -67.489034, 21-Jan-1992, L. Page, L. Nico, P. Ceas, J. Lyons; MCNG 38168 (1 of 3, 86.0 mm SL), Agua Linda creek, 0.5 km upper waters between Puerto Ayacucho and Caicara, approx. 30 km north of Puerto Ayacucho , 5.645368, -67.456057 24-Jan-1998; MCNG 50038 (3, 64.8–73.0 mm SL), Manapiare River, 14.5 Km al NW de San Juan de Manapiare, 5.428611, -66.136111, 4-Dec-2004; UF 77841 (1, 42.5 mm SL), Ventuari River at Tencua, just below Tencua Falls , 5.050752, -65.625381 20-Mar-1981, S. Reid, C. Gilbert. Apure State : AUM 22631 (10, 5, 54.5–87.87 mm SL) Potrerito creek, ca. 15 km N Puerto Paez on road to San Fernando , 6.41194, -67.53194, 26-Dec-1999, collectors: J. Armbruster, M. Hardman, J. Evans, J. Thomas; Bolivar State : AUM 22336 (1, 46.2 mm SL), 6.31583, -67.09611, Ore creek, ca. 50 km SW Los Pijiguaos, Caicara-Puerto Ayacucho road., 25-Dec-1999, J. Armbruster, M. Hardman, J. Evans, J. Thomas .

Diagnosis. Ancistrus patronus differs from all other Ancistrus in the region except A. lithurgicus , A. macrophthalmus , A. maximus and A. nudiceps by having an entirely black body with tiny white to golden dots; from A. leoni by having the abdomen almost as dark as the sides (vs. much lighter); from A. nudiceps by reaching a much smaller maximum size (86 vs. 138 mm SL), by having the distance between the anteromedial plate and the snout greater than or equal to the distance between the anteromedial plate and a line formed by the anterior margins of the nasal apertures (vs. less than); and from A. leoni , A. lithurgicus , and A. macrophthalmus by being deepbodied (vs. flattened), by having the median plate below the posterior edge of the adipose-fin membrane about twice as tall as wide (vs. just slightly taller than), and by the eyes being laterally placed (vs. dorsolaterally placed in A. lithurgicus and almost completely dorsally placed in A. macrophthalmus .

Description. Morphometrics given in Table 5. Size range this study: 43–86 mm SL. A relatively large, robust Ancistrus , body broadest anteriorly, greatest body width near opercles, usually at base of pectoral spines, but sometimes body slightly wider near middle of pectoral-spine length in fish with plump abdomens, thence narrowing progressively to end of caudal peduncle. Head and body not very depressed, greatest body depth just anterior to dorsal-fin origin. Caudal peduncle deep, robust, compressed posteriorly. Dorsal profile of head steeply ascending through length of soft snout, then continuing in gentle concave arc to tip of supraoccipital process where it then descends to dorsal-fin origin and continues its decline to point below tip of adipose-fin spine; then angled up through dorsal procurrent caudal-fin spines. Ventral profile of mouth flat to beneath pectoral-fin insertions, then slightly concave to pelvic-fin insertions, then almost straight to lower caudal-fin spine.

Head wide, interorbital width about equal to head depth, much more than half of head length. Snout rounded with large broad naked margin in males, less wide in females and juveniles. Snout length more than one-half head length. Eye large, interorbital area slightly convex. Oral disk ovate, wider than long. Lips covered with minute papillae, larger near mouth. Lower lip moderate in size, not reaching gill aperture, its border covered with very small papillae. Maxillary barbel very short, its length less than orbit diameter. Jaws short with premaxillary tooth rows forming strong arc and dentary tooth rows forming angle of>135°. Dentary and premaxillary tooth rows strongly curved medially, lateralmost dentary tooth medial to lateralmost premaxillary tooth. Teeth small and numerous (58–120 per jaw ramus), asymmetrically bifid, medial cusp much larger and spatulate, lateral cusp minute and pointed, usually not reaching more than half length of medial cusp, but equal in worn teeth.

Hypertrophied cheek odontodes strongly evertible, nine to 19, stout with tips hooked anteriorly, bases encased in thick fleshy sheaths. Exposed part of opercle roughly triangular, covered with short stout odontodes. Head smooth, bones on back of head not carinate; supraoccipital with margins between surrounding bones and plates usually clearly visible. Lateral plates not carinate.

Ventral surface of head and abdomen naked, no exposed platelets anterior to anal-fin spine. Nuchal plate small and curved posterolaterally. Enlarged odontodes present along edges of lateral plates. Five series of lateral plates anteriorly, three series on caudal peduncle, mid-dorsal and mid-ventral plate series end on caudal peduncle beneath adipose fin. Last plate in median series much smaller than penultimate plate, and median plate below end of adipose fin about twice as high as wide. Base of caudal fin with about eight roughly triangular platelets covering bases of caudal-fin rays.

Dorsal-fin origin situated anterior to vertical through pelvic-fin insertion. First dorsal-fin ray not elongate, but longer than snout length; last dorsal-fin ray reaching adipose-fin spine when depressed. Dorsal-fin base length much longer than dorsal–adipose distance. Adipose fin stout, angled up from body, membrane visible beneath spine. Pectoral spine stout, moderately long, reaching just past pelvic-fin base but not to cloaca. Anal fin small but well developed; base of first anal-fin pterygiophore covered by skin, anal-fin origin posterior to vertical through base of last dorsal-fin ray. Pelvic fins reaching well past anal-fin origin but not past anal-fin tip, inserted at vertical about through second branched dorsal-fin ray. Caudal fin truncate, lower lobe slightly longer than upper.

Tiny odontodes present on body plates, largest on posterior margins of plates. All fin spines with small odontodes, more developed in pectoral-fin spine of males. All fin rays with tiny odontodes on rays.

Meristics (N=47). Mid-dorsal plates 6–18, x= ̃13; median plates 22-24, x= ̃ 23; mid-ventral plates 16–19, x= ̃ 17–18; plates bordering dorsal-fin base 4–8, x̃ = 7; plates between dorsal and adipose fins 4–8 median 6–7; preadipose plates one. Fin-ray formulae invariate: dorsal I,7; pectoral I,6; pelvic i,5; anal i,4; caudal i,14,i. Caudal procurrent spines: dorsal: four to five, x= ̃five; ventral: two to four, x= ̃three.

Sexual dimorphism. ( Fig. 5b ) snout tentacles of nuptial males long, largest 1.5 times eye diameter. Posteromedial tentacles diverging in V- shape along anteriorly triangular snout plates. Naked areas of snout without tentacles rugose, separated from naris by several, wide plates; naked area wide, distance from anteromedial plate to snout greater than or equal to distance from anteromedial plate to line formed between anterior edges of nasal apertures.

Color in alcohol. ( Fig. 19 ) Base color of all fins, dorsum, sides and ventrum of body black, brown or gray, with tiny white dots; dots often lost in preservative. First dorsal-fin membrane with dark pigment near base. Upper and lower tips of caudal fin sometimes white or cream colored.

Life colors. ( Fig. 20 ) Body and fins jet black with tiny white dots. First dorsal-fin membrane with dark pigment near base. Upper and lower tips of caudal fin sometimes white or cream colored.

Distribution. Present in the upper río Orinoco from the río Cinaruco upstream and the río Casiquiare ( Fig. 7 ).

Etymology. Named for good fathers. Patronus is Latin for protector or defender and is derived from pater for father. Males of this genus guard their nests and protect their young until they are fairly large. With their cheek odontodes everted, males can block off nests and potentially injure predators.

Figures

FIGURE 5. Heads, dorsal view, of A. Ancistrus nudiceps AUM 35623, 140.2 mm SL and B. A. patronus, holotype, AUM 39876, 83.6 mm SL demonstrating differences in head shape and tentacle pattern. Ancistrus nudiceps has a longer, more spatulate snout with the point from the edge of medial snout plates to the end of the snout (turquoise line) much shorter than the distance from the edge of the medial snout plates to a line through the anterior margins of the orbits (yellow line, dashed line is the line that demarks the anterior borders of the orbits) while the two lengths are approximately equal in A. patronus. In addition, the anterior margin of the snout plates form a rough V in A. nudiceps and a U in A. patronus (solid white line). Scale = 1 cm. Photos by J.W. Armbruster.

FIGURE 7. Distribution of species of Ancistrus from the northwestern Guiana Shield and neighboring regions.

FIGURE 19. Ancistrus patronus, holotype, in dorsal, lateral, and ventral views, AUM 39876, 83.6 mm SL. Scale = 1 cm. Photos by J.W. Armbruster.

FIGURE 20. Live coloration of head of Ancistrus patronus in dorsal and lateral views, AUM 43868, 79.4 mm SL. Scale = 1 cm. Photos by N.K. Lujan.