Hemiancistrus subviridis, Werneke & Sabaj & Lujan & Armbruster, 2005

Werneke, David C., Sabaj, Mark H., Lujan, Nathan K. & Armbruster, Jonathan W., 2005, Baryancistrus demantoides and Hemiancistrus subviridis, two new uniquely colored species of catfishes from Venezuela (Siluriformes: Loricariidae), Neotropical Ichthyology 3 (4), pp. 533-542 : 538-541

Hemiancistrus subviridis , new species

Figs. 1c and 4

Holotype. MCNG 54032, 133.5 mm SL, Venezuela, Amazonas, río Orinoco 117 km W of La Esmeralda, 03.28998°, -066.60004°, 29 Mar 2005, N. K. Lujan, M. Arce, T. E. Wesley, M. B. Grant, E. L. Richmond, J. Valadez, D. Brooks, F. Brito, & O. Santaella . Paratypes. VENEZUELA, Amazonas, río Orinoco drainage: ANSP 162167 , 1 (1, 149.5 mm SL), río Orinoco at rocks 1 km above La Esmeralda, 14 Mar 1987, W. G. Saul, J. Fernandez, O. Castillo, & M. E. Antonio. ANSP 162178 , 1 (1, 134.8 mm SL), río Orinoco , backwater behind sandy beach 1/2 hr upstream from Isla Tremblador , 10 Mar 1987, W. G. Saul, H. Lopez, J. Fernandez, O. Castillo, M. E. Antonio, & J. Moreno. ANSP 180229 , 4 (1, 93.4 mm SL), AUM 39228, 4 (1, 106.9 mm SL), MCNG 54033 , 3 (1,82.3 mmSL), ríoOrinoco, CucueAmerindian Village 60 km E of San Fernando de Atabapo, 03.97380°, - 067.15821°, 3 Apr 2004, M. H. Sabaj, N. K. Lujan, D. C. Werneke, & L. S. deSouza. AUM 39231, 2 , 1 c&s, río Ventuari beach across the river from Picua Village 34 km ENE of Macuruco 104 km E of San Fernando de Atabapo, 04.11534°, -066.76457°, 5Apr 2004, M.H.Sabaj, N.K. Lujan, D. C.Werneke, L. S. de Souza, & O. León. ANSP 180230 , 2 (2, 77.2–103.6 mm SL), AUM 39244, 2 (2, 89.4–105.6 mm SL), MCNG 54034 , 2 (2, 58.2–103.7 mm SL), río Ventuari 23 km NE of Macuruco 94 km E of San Fernando deAtabapo, 04.08042°, -066.86513°, 5 Apr 2004, N. K. Lujan, D. C. Werneke, M. H. Sabaj, L. S. deSouza, & O. León. ANSP 180231 , 2 (2,97.4–125.2 mmSL), AUM 39283, 3 (3, 51.5–121.0 mm SL), MCNG 54035 , 2 (2, 57.3–109.0 mm SL), río Parucito at raudales Salomon 2.7 km NE of San Juan de Manapiare, 05.34637°, -066.03347°, 16 Apr 2004, D. C. Werneke, N. K. Lujan, & O. León. ANSP 180236 , 3 (1, 121.0 mm SL), AUM 42117, 3 (1,134.4 mm SL), MCNG 54036 , 1 , same data as holotype. ANSP 180233 , 3 (1, 60.3 mm SL), AUM 42124, 3 (1,115.3 mm SL), MCNG 54037 , 2 (1,39.0 mm SL), río Orinoco 33.9 km W of La Esmeralda at Punto Piaroa , 03.14744°, - 065.85381°, 28 Mar 2005, N. K. Lujan, M. Arce, T. E. Wesley, M. B. Grant, E. L. Richmond, J. Valadez, & D. Brooks. AUM 42140, 2 (2, 132.8– 134.2 mm SL), Pasaganado 38 km N of San Fernando de Atabapo, 04.38442°, -067.77444°, 1 Mar 2005, N. K. Lujan, D. C. Werneke, M. H. Sabaj, M.Arce, & T. E. Wesley. ANSP 180232 , 2 (1, 99.9 mm SL), AUM 42146, 2 (1, 108.9 mm SL), ríoVentuari163 kmSEofSamariapo, 04.05736°,-066.93257°, 1 Apr 2005, N. K. Lujan, M. Arce, T. E. Wesley, E. L. Richmond, & M. B. Grant. AUM 42174, 2 (2, 79.7–100.7 mm SL), río Orinoco 60 km E of San Fernando de Atabapo, 03.97401°, - 067.16276, 3 Mar 2005, N. K. Lujan, D. C. Werneke, M. H. Sabaj,& M.Arce. AUM 42212, 2 (2, 36.9–108.8 mm SL), MCNG 54038 , 2 (1, 93.8 mm SL), río Ventuari near ornamental fish market in river, 04.07565°, -066.89285°, 3 Apr 2005, N. K. Lujan, M. Arce, E. L. Richmond, M. B. Grant, & T. E. Wesley. AUM 42929, 1 (1, 108.3 mm SL), río Orinoco at Macuruco landing, 03.95820°, -067.03210°, 30 Mar 2005, N. K. Lujan, M.Arce, E. L. Richmond, M. B. Grant, J. Valadez, D. Brooks, & T. E.Wesley. AUM 42931, 1 (1, 65.0 mm SL), río Orinoco beach and bedrock outcropping 50 km E of San Fernando de Atabapo, 03.97029°, -067.25506, 2 Mar 2005, N. K. Lujan, D. C. Werneke, M. H. Sabaj, M. Arce, R. Betancur, & T. E. Wesley. AUM 42932, 1 (1, 140.2 mm SL), río Orinoco island W of Puerto Venado 4.5 km S of Samariapo 56.5 km SE of Puerto Ayacucho, 05.20708°, - 067.80900°, 28 Feb 2005, N. K. Lujan, D. C. Werneke, M. H. Sabaj, M. Arce, R. Betancur , and T. E. Wesley. MCNG 30361 , 1 (1, 112.0 mm SL), río Orinoco in front of Macuruco , 5 Aug 1994, A. Barbarino, I. Lopez, & R. Berrios .

Non-types. VENEZUELA, Amazonas, río Casiquiare drainage : AUM 42201, 1 (1, 73.3 mm SL), río Casiquiare 153 km NE of San Carlos de río Negro , 02.79877°, -066.00652°, 24 Mar 2005 . ANSP 180234 , 1 (1, 38.3 mm SL) , AUM 42930, 1 (1, 89.4 mm SL) , MCNG 54039 , 1 (1, 51.7 mm SL), río Casiquiare left bank upstream from mouth of río Siapa , 02.15570°, -066.46377°, 19-22 Mar 2005 . ANSP 180235 , 2 , AUM 42933, 2 (1, 146.9 mm SL), río Casiquiare bedrock riffle and outcrop 74.6 km NE of San Carlos de río Negro , 02.36280°, -066,56483°, 9 Mar 2005 . MCNG 12362 , 2 (2, 62.1–65.9 mm SL), raudal Cabarua approximately 5 km N of confluence with río Siapa , 02.11667°, -066.46667°, 18 Apr 1985 .

Diagnosis. Hemiancistrus subviridis can be separated from all other hypostomines except Baryancistrus demantoides by having a light gold-olive base color in life with goldenyellow spots, and from B. demantoides by lacking a membranous connection between the dorsal and adipose fins and by having 9-29 left dentary teeth (vs. 34-51). Hemiancistrus subviridis when preserved is very similar to the sympatric H. guahiborum from which it differs by lacking an orange band at the edge of its dorsal and caudal fins and by having 9-29 left dentary teeth (vs. 28–72). The only other species of Hemiancistrus with light spots are H. chlorostictos , H. fuliginosus , H. macrops , H. meizospilos , and H. votouro . In addition to the light gold-olive base color (vs. dark gray base color), H. subviridis can be separated from H. chlorostictos , H. fuliginosus , H. meizospilos , and H. votouro by having a forked caudal fin (vs. an emarginate caudal fin) and by having 9-29 left dentary teeth (vs. 41-86); and from H. macrops by having the light spots restricted to the anterior half of the body (vs. all over).

In addition, Hemiancistrus subviridis can be separated from all ancistrins except Baryancistrus , other Hemiancistrus , Hypancistrus , Panaque , Parancistrus , Peckoltia , and some Pseudancistrus by lacking odontodes on the opercle; from Ancistrus , Dekeyseria , Lasiancistrus , Neblinichthys , and Pseudolithoxus by having five rows of plates on the caudal peduncle (vs. three); from Hopliancistrus by having more than 10 relatively straight hypertrophied odontodes on the evertible cheek plates (vs. usually less than five strongly recurved hypertrophied odontodes); from Exastilithoxus and Lithoxus by having oval lips (vs. round); from Acanthicus , Chaetostoma , Cordylancistrus , Dolichancistrus , and Leptoancistrus , Leporacanthicus , Megalancistrus , and Pseudacanthicus by having seven dorsal-fin rays (vs. eight or more); from Acanthicus , Dekeyseria , Leporacanthicus , Megalancistrus , and Pseudacanthicus by lacking keels on the lateral plates; from most Pseudancistrus by lacking hypertrophied odontodes around the snout; from Pseudancistrus sidereus and P. megacephalus by having spots only anteriorly on the body (vs. all over); from Baryancistrus by not having the posterior portion of the dorsal-fin membrane expanded; from Parancistrus , Spectracanthicus , and most Baryancistrus by not having the dorsal fin connected to the adipose fin; from Panaque by having viliform teeth (vs. spoon-shaped teeth or elongated teeth); from Peckoltia by having light spots (vs. dark spots or saddles); and from Hypancistrus by having the teeth of the dentary and premaxillary of equal size (vs. dentary teeth longer than premaxillary teeth).

Description. A member of Subfamily Hypostominae , Tribe Ancistrini as diagnosed by Armbruster (2004). Morphometrics in Table 1. Medium-sized loricariids, largest specimen 149.5 mm SL. Body stout. Head sloped at approximate 30° angle to point above anterior portion of eye. Nape ascending slightly to insertion of dorsal fin. Dorsal slope decreasing to insertion of dorsal procurrent caudal rays then ascending to caudal fin. Body depth greatest below insertion of dorsal fin. Ventral profile flat to caudal fin. Caudal peduncle triangular in cross section with dorsal surface flattened. Body widest at insertion of pectoral fins, narrowest at insertion of caudal fin. Snout rounded.

Eyes moderately sized. Iris with dorsal flap. Interorbital space flat. Slight ridge formed between anterodorsal margin of orbit and nares. Supraoccipital pointed posteriorly, not elevated above nuchal plate. Infraorbitals, frontal, nasal, pterotic, and supraoccipital supporting odontodes. Preopercle and opercle not supporting odontodes.

Lips covered with short, wide papillae. Lower lip wide, upper lip narrow. Maxillary barbel only barbel present, reaching more than one third of distance to gill opening.

Median plates 23–25 (mode = 24). Plates unkeeled. Five caudal peduncle plate rows. Plates on all surfaces of body except for small naked upside down V-shaped wedge on the anteroventral margin of snout, throat, and abdomen behind pectoral. Some small embedded plates ventral to pectoral girdle and along ventromedial insertion of pectoral fin. Evertible cheek plates supporting hypertrophied odontodes that can be everted perpendicular to head. Cheek odontodes 17–74 (mode = 60). Longest evertible cheek odontode reaching cleithrum. Hypertrophied cheek odontodes relatively weak. Slightly longer odontodes present along dorsal-, adipose-, pelvic-, caudal-, and pectoral-fin spines; larger individuals with hypertrophied odontodes at tip of pectoral spine.

Dorsal fin II,7; dorsal spinelet V-shaped, dorsal-fin locking mechanism present, last ray of dorsal fin reaching insertion of adipose spine when adpressed. Adipose fin with single preadipose plate and moderately long spine. Caudal fin i,14,i; caudal fin forked, ventral lobe longer than dorsal lobe, dorsal procurrent caudal rays four, ventral procurrent caudal rays four. Pectoral fin I,6; pectoral-fin spine reaching beyond insertion of pelvic-fin spine when adpressed ventral to pelvic fin. Pelvic fin i,5; pelvic-fin spine extending beyond base of anal fin when adpressed. Anal fin i,4; anal-fin spine slightly shorter than first ray.

Teeth bicuspid with lateral lobe three-quarters length of medial lobe and distal tip of lateral cusp one-half width of tip of medial cusp. 9-29 left dentary teeth (mode = 17). 10–28 left premaxillary teeth (mode = 19).

Color in life. Adults with light golden-olive ground color on body and fins. Head, anterior sides and skin covering dorsalfin base with distinct round golden-yellow spots. Spots usually confined to portion of sides anterior to last dorsal-fin ray, but sometimes continuing on dorsolateral plates to below adipose fin or slightly beyond. Spots largest and more remotely spaced on anterior body below dorsal fin, becoming gradually smaller and more closely spaced towards and onto snout. Dorsal fin with distinct golden-yellow spots largely confined to basal two-thirds of spine and rays (lacking from membranes and distal portions of spine and rays). Pectoral fin with smaller golden-yellow spots largely confined to basal one-half to basal three-quarters of rays.

Color in alcohol. Adults with head, sides and fins nearly uniform light to medium gray-brown (becoming lighter posteriorly); plated undersurfaces tan, naked abdominal region white to cream-colored (without markings). Light spots on head and anterior sides clearly evident; light spots on head smaller, more numerous, and more tightly spaced; lateral plates anterior to dorsal fin usually with two to five light spots per plate; light spots also evident on skin along dorsal-fin insertion. Light spots on dorsal fin largely restricted to basal two-thirds of spine and rays, lacking on membranes. Light spots usually lacking on paired fins but sometimes evident on anterior membranes of pectoral fin. Juvenile coloration more or less as described for adults except light spots in fins lacking.

Range. Hemiancistrus subviridis is known from the río Orinoco upstream of Atures rapids to río Iguapo, the río

Ventuari, and the río Casiquiare upstream of the río Siapa ( Fig. 3 ).

Etymology. From the Latin subviridis meaning greenish in reference to the olive base color in life.

Gut morphology and ecology. Gastrointestinal tract brown with yellow-green fat deposits, loosely attached to intestinal wall. Esophagus turns 90° toward right upon entering peritoneal cavity, extends straight to right for short distance, turns 90° toward posterior before transitioning into proximal (cardiac) stomach. Cardiac stomach extends posteriorly for two thirds of length then transitions into distal (pyloric) stomach by making a 180° turn such that pyloric portion exits anteriorly and lies to right of cardiac portion. Total length of stomach approximately 15 mm. Proximal intestines exit the anterior-facing pyloric stomach, turn 180° to cross dorsally over esophagus, then continuing posteriorly towards anus. Near the anus, the proximal and distal ends of intestines begin a parallel, clockwise spiral toward the left with coils accruing ventral toward stomach and esophagus. Proximal intestines spiral clockwise for half of entire intestinal length, turn 180° at their middle, then distal portion spirals back to anus. Length of intestines and stomach from 15–17 times SL. External diameter of intestines ranges from 1–2 mm.

Hemiancistrus subviridis were most frequently encountered in cracks and interstitial spaces of granitic rocks in flow. Gut contents of all individuals consisted largely of small grained (<0.001 mm diameter) mineral/organic matrix resembling clay, with some larger (~1.0 mm diameter) grains resembling silica sand. Organic material embedded in matrix of one individual (AUM 39283) included pieces of a moss-like nonvascular plant (Bryophyta), intact mayfly larvae (Ephemeroptera), midge larvae ( Chironomidae ), unidentified fly larvae ( Diptera ), a clump of filamentous algae, a piece of lignified vascular plant, and an ingested tooth of presumed endogenous origin. Organic components of diet inAUM 42140 consisted of unidentifiable pieces of insect exoskeleton, pieces of unidentifiable plant matter, and ingested teeth of presumed endogenous origin (n=2). The only identifiable organic components in anterior gut of AUM 42124 were ingested teeth of presumed endogenous origin (n=13).

Figures

Fig. 1. Live specimens of a: Baryancistrus demantoides, adult,AUM 42034, paratype, 96.3 mm SL; b: B. demantoides, juvenile, MCNG 54031, paratype, 54.1 mm SL; c: Hemiancistrus subviridis,AUM 42933, 146.9 mm SL. Photos by M.H. Sabaj.

Fig. 4. Hemiancistrus subviridis MCNG 54032, 133.5 mm SL; holotype, dorsal, lateral, and ventral views. Photos by D.C. Werneke.

Fig. 3. Localities of Baryancistrus demantoides (triangle), Hemiancistrus subviridis (dots), and both species (squares). 1 is the type locality of B. demantoides and 2 is the type locality of H. subviridis.