Ancistrus saudades, 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 : 43-47

Ancistrus saudades new species

( Figs. 21–22 )

Holotype. CSBD F 1722 (1, 107.48 mm SL) Rupununi , Guyana, Region 9, Amazon / Branco / Takutu River, creek at second wooden bridge from Moco-Moco power station, 13-Nov-2007, 3.30318 o, -59.65038 o. L. de Souza, D. Taphorn, J. Baskin, T. Geerinckx and J. Hawn.

Paratypes. Guyana, Region 9, Amazon / Branco River Basin : AUM 35631 (16, 7, 70.2–96.0 mm SL), Rupununi, Takutu River drainage, Yuora River, tributary of the Ireng River, 6.7 km NE Karasabai, J. Armbruster, M. Sabaj, D. Werneke, C. Allison, M. Thomas, C. Chin, D. Arjoon 31-Oct-2002 ; AUM 35633 (20, 9, 44.3–83.2 mm SL), Rupununi , Takutu River drainage, Sauriwau River 31.2 km NW village of Sand Creek, 3.11432 o,- 59.77544 o, J. Armbruster, M. Sabaj, D. Werneke, C. Allison, M. Thomas, C. Chin, D. Arjoon, 4-Nov-2002 ; AUM 35634 (18, 4, 60.7–79.1 mm SL), Rupununi , Moco-Moco creek at Moco-Moco hydropower station, 18.8 km SE of Lethem, 3.29672 o, -59.64466 o, J. Armbruster, M. Sabaj, D. Werneke, C. Allison, M. Thomas, C. Chin, D. Arjoon, 5-Nov-2002 ; AUM 37989 (6, 3, 46.3–77.9 mm SL), Rupununi , Kumu Creek 15.2 km SE of Lethem 3.25953 o, , - 59.72373 o, J. Armbruster, M. Sabaj, M. Hardman, D. Arjoon, N. Lujan, L. de Souza, 2-Nov-2003 ; AUM 48283 (32, 2, 65.0– 73.45 mm SL), Rupununi , Takutu River drainage, Moco-Moco Creek at Moco-Moco hydropower station, 18.8 km SE of Lethem, 3.29663 o, -59.64507 o, L. de Souza, D. Taphorn, J. Baskin, T. Geerinckx and J. Hawn, 13-Nov-2007 ; AUM 48587 (6, 2, 62.6–73.5 mm SL), Rupununi , Takutu River drainage, first creek downstream of Moco-Moco Creek at power station, 3.30095 o, -059.64908 o, L. de Souza, D. Taphorn, J. Baskin, T. Geerinckx and J. Hawn, 13-Nov-2007 ; AUM 50020 (24, 3, 68.4–75.6 mm SL), same data as holotype; FMNH 69963 (1, 48.8 mm SL) Moco Moco River behind hostel at St. Ignacius, 3.35886, -59.78959, 15-Dec-1968 . Guyana, Region 8, Amazon / Branco River Basin: AUM 67043 (2, not measured), Takaika Creek , left bank tributary of Ireng River that enters below lower Orinduik Falls, 4.72366, -60.03062, local fishermen, 2-Jan-2016 ; AUM 67055 (5, not measured), Tumong Creek , left-hand tributary of Ireng River, 4.71388, -60.02234, N. Lujan, J. Armbruster, D. Werneke, M. Ram, 3-Jan-2016 ; AUM 67104 (4, 0), Tumong Creek , left-hand tributary of Ireng River, 4.71971, -60.01311, D. Werneke, N. Lujan, J. Armbruster, M. Ram, 6-Jan-2016 ;

Non-types. Guyana, Region 9, Amazon River Basin: FMNH 53090 (1, 75.6 mm SL), Ireng River, near “Holmia” (this is likely an error as Holmia is in the upper Potaro River Basin , not the Ireng, excluded from type series because of uncertain locality), 1908; Venezuela, Orinoco River Basin (excluded from type series): ANSP 146219 (2, 51.0–96.0 mm SL) Caura River drainage, Cuchima creek ( Cusimi River ), ca 20 mi upstream from junction of Caura River with Erebato River (between rivers), 5.71208, -64.55980, 7-Feb-1977 ; AUM 36663 (4, 60.6–72.5 mm SL), Caroní River drainage, Samey River , 57.5 km WSW of Santa Elena, 6 km S. of El Piaje, on foot path, 4.124336, -61.043975, 14-Jun-2003 ; AUM 39477 (3, 44.0– 61.3 mm SL), Ventuari River, above Salto Tencua , 58 km ESE of San Juan de Manapiare, 5.04777, -65.61583, 21-Apr-2004 ; FMNH 110066 (1, 77.0 mm SL), Caura River drainage, creek near its mouth with upper Caura , River at Cejiato, 5.55780, -64.31360, 28-Nov- 00 ; FMNH 110069 (1, 51.2 mm SL), Caura River drainage, Creek at Tojanaño that flows into Tawadu River , 6.33750, -65.02500, 5-Dec-00 ; MCNG 12071 (1, 63.9 mm SL), Caura, Creek a tributary of Guana River , 4.159326, -63.749342, 26-Oct-1982 ; MCNG 20877 (2, 52.0– 62.6 mm SL), Caura River drainage, Nichare River in a rivulet behind a small island, 6.22972, -64.93861, 19-Mar-1989 ; MCNG 23201 (2, 42.9–60.7 mm SL), Caura River drainage, Nichare River, slabs near Serapia creek , Bolivar state, 6.55000, -64.85000, 25-Mar-89 ; MCNG 48095 (5, 57.0–64.0 mm SL), Rio Samey , 57 Km al WSW de Santa Elena 4.42278, -61.59583, 14-Jun-2003 ; UF 78052 (1, 61.2 mm SL), Caura River drainage, confluence of río Erebato with Caura (several localities in immediate area), 5.9 3159, -64.42734, 23-Mar-1981 .

Diagnosis. Ancistrus saudades differs from all other Ancistrus in the region except A. brevifilis , A. leucostictus , and A. triradiatus by having large spots on the caudal fin, abdomen, and sides (these can be obscured in preserved specimens, but spots generally remain in the fins, vs. all dark color with small white dots, dots may be absent in preserved specimens). Ancistrus saudades can be separated from A. leucostictus by having the adpressed dorsal fin reaching maximally to the middle of preadipose plate (vs. to middle of the adipose-fin spine or beyond) and by having the pectoral-fin spine when adpressed ventral to the pelvic fin not reaching the base of the cloacal tube (vs. reaching the base of the cloacal tube in adults) and by having relatively smaller light spots and wider dark interspaces on the anterolateral plates and posterodorsal head bones with the interspaces half to equal in width to the spots or spots not visible in this region in preserved specimens (vs. spots relatively large with the interspaces much less than half the size of the interspaces and at least some spots in this region visible in all specimens; the difference in spots vs. interspaces generally works on the abdomen as well); from A. brevifilis by having round spots on the caudal fin (vs. oval spots), and from A. brevifilis and A. triradiatus by having spots on the abdomen in life (vs. spots absent; rare specimens of A. triradiatus have spots).

Description. Morphometrics given in Table 6. Size range of examined specimens 42.9–107.48 mm SL. A medium sized Ancistrus , body broadest anteriorly, greatest body width just posterior to opercles, then narrowing progressively to end of caudal peduncle. Head and body depressed, greatest body depth between level of pectoral- fin insertions and dorsal fin origin. Caudal peduncle deep, robust, compressed posteriorly. Dorsal profile of head ascending steeply in convex arc from tip of snout to just posterior of orbits, ascending in straight line to posterior tip of supraoccipital, then descending to dorsal-fin origin. From the dorsal-fin origin descending in a slight convex arc to just posterior of dorsal-fin base, then straight to caudal fin. Ventral profile flat to slightly convex from tip of snout to pelvic-fin insertions. Abdomen flat to slightly concave to pelvic-fin insertions, from there, straight to slightly convex and sloping gently ventrally towards caudal fin.

Head wide, interorbital width equal or slightly less than head depth, slightly less than half of head length. Snout rounded with large broad naked margin in males, less wide in females and juveniles. Snout length about onehalf head length. Eye moderate in size, 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 numerous (49–120 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, equal in worn teeth. Hypertrophied cheek odontodes strongly evertible, eight to 14, stout with tips hooked anteriorly, bases encased in thick fleshy sheaths. Exposed part of opercle small, roughly triangular with few 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, lateral line pores distinctly visible, horizontally elongate.

Ventral surface of head and abdomen naked, no exposed platelets anterior to anal-fin spine. Nuchal plate small and curved posterolaterally. No enlarged odontodes at edge of lateral plates. Five series of lateral plates anteriorly, three series on caudal peduncle, mid-dorsal and mid-ventral plate series ending on caudal peduncle beneath preadipose plate just anterior to embedded adipose-fin spine. Last plate in median series slightly smaller than penultimate plate, and median plate below end of adipose fin about twice as high as wide. Base of caudal fin with six platelets covering bases of caudal-fin rays.

Dorsal-fin origin situated anterior to vertical through pelvic-fin insertion. First dorsal-fin ray elongate, just slightly longer than snout length; last dorsal-fin ray reaching first preadipose plate when depressed. Adipose-fin spine (if present) embedded, oriented parallel to horizontal axis of body, membrane present, not visible beneath spine. Pectoral spine long and stout, when adpressed ventrally not reaching to the cloaca. Anal fin small but well developed; base of first anal-fin pterygiophore covered by skin, its origin below or posterior to vertical through base of last dorsal-fin ray. Pelvic fins reaching well past anal-fin origin, inserted posterior to vertical through first branched dorsal-fin ray. Caudal fin truncate, lower lobe 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=56). Mid-ventral plates 17; median plates 22–25, x= ̃23; mid-dorsal plates 12–19, x= ̃16; plates bordering dorsal-fin base six to eight, x= ̃ seven; plates between dorsal and adipose fins four to seven, x= ̃ six; preadipose plates one. Fin-ray formulae invariable: dorsal II,7; pectoral I,6; pelvic i,5; anal i,4; caudal i,14,i. Caudal procurrent spines: dorsal: two to five, x= ̃five; ventral: two to four, x= ̃three.

Sexual dimorphism. Snout tentacles of nuptial males long, largest over twice 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. 21 ) Dorsal and lateral base color dark gray or brown mottled with light brown spots on top of head and body. Plateless area of snout and tentacles also dark with irregular lighter spots. All fins with alternating dark and light spots. Ventral surface of head and abdomen tan to yellowish tan, oral disk yellowish, plates of ventral surface of caudal peduncle with posterior margins darker brown, forming alternating light and dark pattern. Small white spots on ventral surface of head and abdomen. Dark interspaces on the head, anterior body, and abdomen usually greater than half the width of the spots.

Life colors. ( Fig. 22 ) Dorsum mottled dark and light brown with small white spots on the extent of the body. Body posterior to dorsal-fin origin equally spotted, and base color is dark and light brown. Preadipose plate and vestiges of adipose-fin spine outlined in yellow. Sides with irregular light and dark spots. Ventrum of body with light brown base color and tightly spaced small white spots. Oral disk and adjacent area on chest pink to whitish. Fin membranes lightly pigmented, grayish, but spines and rays tan in color with spots on all fins. Dark interspaces on the head, anterior body, and abdomen usually greater than half the width of the spots.

Distribution. Ancistrus saudades has a distribution that matches the upper portion of the Proto-Berbice River drainages: Takutu, upper Ventuari, upper Caura, and upper Caroni river drainages of Guyana, Venezuela, and Brazil ( Fig. 7 ). Type locality was restricted to the Takutu drainage of Guyana / Brazil because the Orinoco populations may be distinct.

Etymology. The Portuguese word saudades is used word saudades , used to express a deep longing or profound melancholy attached to a person, place or experience. It has a deeper tone and meaning than a direct English translation and reflects the lead author’s connection to her Brazilian heritage and her nostalgia for field work in remote wilderness areas that yielded these museum collections.

Figures

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

FIGURE 21. Ancistrus saudades, holotype, in dorsal, lateral, and ventral views, CSBD F 1722, 107.5 mm SL. Scale = 1 cm. Photos by J.W. Armbruster.

FIGURE 22. Live coloration of Ancistrus saudades in dorsal and lateral views, AUM 67055, 58.1 mm SL. Scale = 1 cm. Photos by N.K. Lujan.