Lasiancistrus mayoloi Eigenmann, 1912

Poveda-Cuellar, José Luis, Conde-Saldaña, Cristhian Camilo, Villa-Navarro, Francisco Antonio, Lujan, Nathan K. & Santos, Jorge Abdala Dergam dos, 2023, Phylogenetic revision of whisker-cheeked suckermouth catfishes (Loricariidae: Lasiancistrus) from east of the Andes: five species where once there were two, Zoological Journal of the Linnean Society 199 (3), pp. 688-712 : 703-705

Lasiancistrus mayoloi Eigenmann, 1912

( Fig. 8 ; Tables 4 and 5 )

Hemiancistrus mayoloi Eigenmann, 1912: 10 (type locality: San Juan River , Istmina, Colombia; holotype: FMNH 56036 ). Henn (1928: 84) remarks on holotype at Carnegie Museum.

Ancistrus planiceps Meek, 1913: 79 (type locality: Tuyra River , Boca de Cupé, Panamá; holotype: FMNH 7580 ). Ibarra and Stewart, 1987: 8 remarks on holotype at FMNH.

Diagnosis: Lasiancistrus mayoloi differs from all trans-Andean congeners except L. guacharote by having the head with dark brown base colour and lighter brown spots (vs. head with light brown base colour and darker brown reticulations or stripes) and the snout more acute (vs. rounded; Fig. 8 ), from L. guacharote by lacking abdominal plates (vs. abdomen with patch of plates medial to pectoral-fin spine insertion), from L. volcanensis by having the dorsal rim of the orbit slightly elevated above the interorbital space (vs. dorsal rim of orbit level with interorbital space), abdominal region pyriform (vs. rectangular; Fig. 6 ) and seven ribs, (vs. eight), from L. wiwa by having the parieto-supraoccipital posterior margin projected posteromedially (vs. not posteromedially projected; Fig. 6 ) and the posterior margin of the urohyal rounded (vs. V-shaped; Figs 7 ), and from L. caucanus by the suture between the parieto-supraoccipital and compound pterotic being concave (vs. straight; Fig. 5 ).

Description: Morphometrics are presented in Table 4 , meristics in Table 5 . Abdomen naked. Body broadest anteriorly, narrow (depressed), with greatest body width at cleithrum. Dorsal profile gently ascending from snout to supraoccipital, flat to dorsal-fin origin, gently descending in straight line to dorsal procurrent caudal-fin rays, then slightly ascending to dorsal caudal-fin insertion. Body depth greatest at dorsal-fin origin. Ventral profile flat from snout to ventral caudal-fin insertion. Robust caudal peduncle almost triangular in cross-section: flaưened ventrally, with flaưened flanks converging to more acute dorsum.

Twenty four median plates (mode = 24); three predorsal plates; six plates along dorsal-fin base; seven plates between dorsal and adipose fins; five plates between adipose and caudal fins; 10 or 11 plates between anal and caudal fins (mode = 10); three horizontal series of lateral plates on caudal peduncle. Parieto-supraoccipital level with nuchal region. Nuchal plate small and curved posterolaterally. Snout slightly acute. Eye small (orbit diameter 16.4 ± 1.3% of head length), with dorsal rim of orbit slightly elevated above interorbital space. Iris operculum present. Frontals, infraorbital, nasals, opercles, pterotics, sphenotics and supraoccipital supporting odontodes. Cheek odontodes robust and sharp (mode = 17, N = 35).

Whisker-like odontodes present in evertible cheek mass and in some individuals at anterolateral corner of snout and oriented ~90° from head. Odontodes on tip of pectoral-fin spine slightly hypertrophied. Odontodes on lateral plates not enlarged to form keels. Lips covered with minute hemispherical papillae; papillae larger near mouth. Lower lip wide, reaching almost to pectoral girdle; upper lip narrow. Maxillary barbel short, not reaching gill opening. Teeth bicuspid; 44–70 less dentary teeth (mode = 63); 40–65 less premaxillary teeth (mode = 54).

Dorsal-fin origin situated slightly anterior to vertical through pelvic-fin insertion. Dorsal-fine spine length shorter than snout length; last dorsal-fin ray reaching first or second preadipose plate when depressed. Adipose-fin spine curved, stout, not embedded; membrane present, easily visible beneath spine. Pectoral-fin spine reaching almost one-third of pelvic-fin base when adpressed; pectoral-fin spine reaching middle of pelvic fin in some larger specimens. Pelvic-fin spine reaching middle of anal-fin base when adpressed; central rays of pelvic fin extend beyond middle of anal fin base in some larger specimens. Unbranched anal-fin ray slightly shorter than first branched ray. Caudal fin slightly forked; ventral lobe longer than dorsal lobe. Tiny odontodes present on body plates and all fin spines with small odontodes, more developed on first two pelvic-fin rays in larger males. Dorsal fin I,7; caudal fin i,14,i; pectoral fin i,6; pelvic fin i,5; anal fin i,5. Twenty-six ertebrae (N = 4). Seven ribs (N = 4).

Coloration in life: Head and body with dark brown base colour. Head with approximately naris-sized lighter brown spots; spots smaller anteriorly. Body with lighter brown wavy stripes; stripes forming four dorsolateral rows in some specimens. Specimens from Bayano River basin have large light brown spots posteriorly along the flank. Abdomen uniformly light brown. All fins with light brown bands. Adipose fin uniformly dark.

Coloration in alcohol: Similar to live coloration but faded, with less distinct paưerning.

Distribution: Lasiancistrus mayoloi is distributed throughout Pacific Coast drainages of northern Colombia (Baudó, San Juan) and southern Panamá (Bayano, Tuyra) ( Fig. 1 ) and the Caribbean slope Atrato River basin in Colombia and Mandinga River basin in Panamá.

Comments: Lasiancistrus mayoloi was originally described as Hemiancistrus mayoloi Eigenmann, 1912 from the San Juan River at Istmina, Colombia. Here, L. planiceps , originally described as Ancistrus planiceps Meek & Hildebrand, 1913 from the Tuyra River in Panama, is considered as a junior synonym of L. mayoloi . The earlier publication date of the former makes this the senior valid synonym. Exceptionally high interspecific COI genetic distance (> 3.0%) supports the recognition of L. mayoloi as a distinct species widely distributed along the Chocó biogeographical region in Panamá and Colombia. However, a high intraspecific distance value (1.73%) also suggests that this species could still harbour hidden diversity.

Material examined: Pacific Coast, Colombia, Chocó Department, Baudó River drainage: CZUTIC 21298, two individuals, 81.6–87.1 mm SL, Urudó River , 5°13 ʹ 45.0 ″ N, 76°58 ʹ 01.0 ″ W ; CZUTIC 21324, six, 35.8–104.4 mm SL, Salao Creek , 5°11 ʹ 26.0 ″ N, 76°57 ʹ 03.0 ″ W ; San Juan River drainage: CZUTIC 21400, four, 44.4–110.6 mm SL, San Juan River , 5°19 ʹ 41.0 ″ N, 76°17 ʹ 01.0 ″ W ; CZUTIC 21423, nine, 24.7–73.3 mm SL, Chato River , 5°15 ʹ 00.0 ″ N, 76°31 ʹ 01.0 ″ W ; CZUTIC 21345 (c&s), nine, 39.5–91.6 mm SL, Condoto River , 5°05 ʹ 46.0 ″ N, 76°40 ʹ 06.0 ″ W ; CZUTIC 21366, four, 79.21–70.0 mm SL, Iró River , 5°06 ʹ 34.0 ″ N, 76°40 ʹ 02.0 ″ W ; CZUTIC 21386, one, 60.9 mm SL, Tadocito River , 5°16 ʹ 08.0 ″ N, 76°31 ʹ 03.0 ″ W ; FMNM 56037 (ph), two, 2.5–85.7 mm SL , paratypes, San Juan River at Istmina Panamá, Tuyra River drainage: FMNH 7580 (ph & xr), one, 147.6 mm SL , holotype of L. planiceps, Tuyra River at Boca de Cupe. FMNH 26293 (ph), one, 82.5 mm SL , paratype of L. planiceps, Cana River ; USNM 78311 (ph), two, 121.2–177.1 mm SL, mouth of Yape River; USNM 280394 (ph), one, 125, 3 mm SL, Tuyra River between Calle Larga and Pinogana above El Real Pacific, 08°07 ʹ N, 077°42 ʹ W ; USNM 293418 (ph), one, 138.0 mm SL, Tuyra River 0.5 km above Boca de Cupe, 08°03 ʹ N, 077°06 ʹ W . MCZ88615 (ph), one, 15–36 mm SL, Pirre River , above El Real (Tuira Dr.), 8°06 ʹ 30.0 ″ N, 77°45 ʹ 30.0 ″ W . MCZ88614 (ph), one, 64–87 mm SL, Pucuro River 3–4 km above confluence with Tuira River , 8°00 ʹ 30.0 ″ N, 77°31 ʹ 30.0 ″ W . Bayano River drainage: MCZ57075 (ph), one, 84.0 mm SL, probably Canita River , on large rock ledge 0.5 km upriver of construction camp and headquarters, 9°13 ʹ 13.4 ″ N, 78°50 ʹ 41.1 ″ W . Atlantic Coast, Colombia, Chocó Department, Atrato River drainage: CZUTIC 21457, eight, 31.1–72.1 mm SL, Tutunendo River , 5°44 ʹ 39.0 ″ N, 76°31 ʹ 05.0 ″ W ; CZUTIC 21488, two, 22.1– 59.8 mm SL, La Piedra Creek , 5°44 ʹ 31.0 ″ N, 76°31 ʹ 05.0 ″ W .

Figures

Figure 1. Geographical distributions of trans-Andean species of Lasiancistrus individuals and species examined in this study. Key:purple stars, Lasiancistrus caucanus; orange triangles, Lasiancistrus guacharote; green circles, Lasiancistrus mayoloi; red diamonds, Lasiancistrus volcanensis; yellow squares, Lasiancistrus wiwa.

Figure 5. Dorsal view of anterior portion of body.A, Lasiancistrus caucanus, CZUTIC12434, 98.83 mm standard length (SL). B, Lasiancistrus volcanensis, CZUTIC5898, 83.59 mm SL. C, Lasiancistrus mayoloi, CZUTIC21345, 91.68 mm SL.D, Lasiancistrus wiwa, CZUTIC17449, 79.55 mm SL. Abbreviations: F, frontal; PT, compound pterotic; SO, parieto-supraoccipital; SP, sphenotic. Scale bars:10 mm.

Figure 6. Ventral view of abdominal region.A, Lasiancistrus caucanus, CZUT-IC 12434, 98.83 mm standard length (SL). B, Lasiancistrus volcanensis, CZUT-IC 5898, 83.59 mm SL.C, Lasiancistrus mayoloi, CZUT-IC 21345, 91.68 mm SL. D, Lasiancistrus wiwa, CZUT-IC 17449, 79.55 mm SL. Scale bars: 1 mm.

Figure 7. Urohyal (UH) and hypohyals (HH) in ventral view. A, Lasiancistrus wiwa, CZUTIC17449, 79.55 mm standard length (SL). B, Lasiancistrus caucanus, CZUTIC12434, 98.83 mm SL. C, Lasiancistrus volcanensis, CZUTIC5898, 83.59 mm SL. D, Lasiancistrus mayoloi, CZUTIC21345, 91.68 mm SL. Scale bar: 1 mm.

Figure 8. Lasiancistrus mayoloi Eigenmann, 1912. CZUT-IC 21298, 87.17 mm standard length, from Río Urudó, Baudó river.Scale bar: 10 mm. Photographs by N.K. Lujan.