Pseudancistrus kwinti, Willink, Philip W., Mol, Jan H. & Chernoff, Barry, 2010

Willink, Philip W., Mol, Jan H. & Chernoff, Barry, 2010, A new species of suckermouth armored catfish, Pseudancistrus kwinti (Siluriformes: Loricariidae) from the Coppename River drainage, Central Suriname Nature Reserve, Suriname, Zootaxa 2332, pp. 40-48 : 41-46

Pseudancistrus kwinti , new species

( Figs. 1–2 , Table 1 )

Common name: Coppename Catfish

Previous citations: Peckoltia sp. (new), Pseudancistrus barbatus, Berrenstein (2005)

Peckoltia sp. 1, Pseudancistrus barbatus, Mol et al. (2006)

Peckoltia sp., Willink & Sidlauskas (2006)

Holotype: FMNH 116976, 94.3 mmSL, Suriname, Sipaliwini State, Coppename River at base of Sidonkroetoe-val rapids, Central Suriname Nature Reserve, 4º31’51”N, 56º30’56”W, J.H. Mol, B. Chernoff, P.W. Willink, and M. Cooperman, 9 March 2004.

Paratypes: NZCS F7066, 95.7 mm SL, Suriname, Sipaliwini State, Rapids of Midden Coppename River, Central Suriname Nature Reserve, 4º12’53”N, 56º35’54”W, J.H. Mol, B. Chernoff, P.W. Willink, and M. Cooperman, 2 March 2004; FMNH 116975, 43.9 mm SL, Suriname, Sipaliwini State, Coppename River at head of Tonckens-val rapids, Central Suriname Nature Reserve, 4º25’22”N, 56º31’34”W, J.H. Mol, B. Chernoff, P.W. Willink, and M. Cooperman, 23 February 2004.

Diagnosis: Pseudancistrus kwinti can be diagnosed from all other described Pseudancistrus by the following combination of characters: dentary papillae absent (versus present in P. coquenani (Steindachner) , P. o r i n o c o (Isbrücker et al.) ( Fig. 3 ), P. pectegenitor Lujan et al. , and P. yekuana Lujan et al. ), mid-dorsal plate row complete (versus incomplete in P. genisetiger Fowler , P. papariae Fowler , and P. re u s Armbruster & Taphorn), coloration mottled or with bars (versus dark with white spots in P. barbatus (Valenciennes) , P. corantijniensis de Chambrier & Montoya-Burgos, P. depressus (Günther) , P. longispinis (Heitmans et al.) , P. niger (Norman) , P. nigrescens Eigenmann , and P. sidereus Ambruster or base of plates dark and edges pale in P. guentheri (Regan)) , and hypertrophied odontodes along edge of snout (versus largely restricted to cheek plates in P. brevispinis (Heitmans et al. )) .

Description: Morphometric data in Table 1 . Ventral surface flattened. Lateral profile of snout relatively straight at approximately 45º angle. Profile curves from anterior of eye to supraoccipital, then increases slightly to dorsal-fin origin, the highest point on the body. Profile relatively straight and decreasing from dorsal-fin origin to caudal fin. Body relatively deep, dorsal-fin origin to pectoral-fin origin 30.3–32.0% of standard length. Median lateral plates 24–25. Caudal peduncle plate rows 5. Plates covered by odontodes, but not keeled. Hypertrophied odontodes along posterior edge of plate. Cheek plates evertible to ~20º from head. Abdomen without plates. No plates immediately around anus.

Dorsal profile of snout rounded. Head width widest at evertible cheek plates. Body narrows from evertible cheek plates to caudal fin. Caudal peduncle compressed horizontally. Head relatively smooth. Anterior orbital rim slightly elevated. Low ridge from tip of snout to between nares. Eyes directed dorsolaterally. Orbit diameter 16.6–22.4% of head length. Nares closer to eyes than to tip of snout. Hypertrophied odontodes along edge of snout, 15 (juvenile)–67 (adult) on evertible cheek plates. Hypertrophied odontodes straight and directed laterally.

All spines and rays on all fins with odontodes. Odontodes slightly larger on spines and unbranched rays. Pectoral fin I6, reaching posterior end of pelvic-fin base when adpressed. Spine stout. First three branched rays extend distal of tip of spine. Distal margin convex. Pelvic fin i5. Origin equal to second branched ray of dorsal fin, reaching posterior end of anal-fin base when adpressed. Unbranched ray hypertrophied and strengthed. First four branched rays extend distal of tip of unbranched ray. Distal margin convex. Anal fin i4 (NZCS F7066 anal fin i5, but appears malformed). Origin equal to dorsal-fin termination, reaching middle of adipose fin when adpressed. First three branched rays extend distal of tip of unbranched ray. Distal margin convex. Dorsal fin Ii7, with I and i fused. Origin anterior of pelvic fin, reaching just posterior end of adiposefin origin when adpressed. Distal margin convex. Adipose fin I, not reaching caudal fin. Membrane extends beyond distal tip of spine. Distal margin convex. Caudal fin i14 i. Base at approximately 65º angle, such that dorsalmost point of base is anterior of ventralmost point. Regardless of angle, caudal-fin ventral edge slightly longer than dorsal edge. Interior branched rays shorter than exterior unbranched rays, forming concave distal margin. Dorsal procurrent caudal-fin rays 5 and ventral procurrent caudal-fin rays 3 in FMNH 116975.

Holotype Range Average SD Standard length (mm) 94.3 43.9–95.7 78.0 29.5

Mouth extending ¾ of distance across head. Premaxillary- and dentary-tooth rows gently curved. Premaxillary teeth 46–53. Dentary teeth 45–61. Teeth villiform, on stalks, bicuspid, with lateral cusp 50–85% of the length of the medial cusp. Buccal papilla present. Dentary papillae absent. Lips not extending beyond margin of head. Posterior lobe longer than anterior lobe. Ventral surface of both lobes covered with papillae. Papillae fairly uniform in size, slightly larger towards mouth. Lip margins smooth except for slight unevenness caused by papillae. Posterior lip margin reaching level of opercular opening. Barbels short, not reaching halfway point to posterior margin of lip.

Color in alcohol: Juvenile head brown with two faint pale bars ( Fig. 1 ). First bar from ventralposterior corner of eye to cheek plate. Second bar from posterior margin of supraoccipital to base of pectoral spine. Body with alternating dark and pale bars. The four dark bars approximately twice as wide as pale bars (three or four plates wide versus one or two). Bars angled such that dorsal portion is anterior to ventral portion. First pale bar starts at dorsal-fin origin. Second pale bar starts near third branched ray of dorsal fin. Third pale bar starts at dorsal-fin termination. Fourth pale bar starts at adipose-fin origin. Ventral half of body slightly fainter than dorsal half.

Dorsal fin with three alternating dark and pale bars confluent with the bars on the body. Distal margin pale. Adipose fin with one distal dark bar. Within dark bar, leading edge of fin and margin between fin and body are more heavily pigmented. Caudal fin with two wide alternating dark and pale bars. Caudal-fin base pale. Caudal-fin distal margin a wide dark bar with a very narrow hyaline edge. Pectoral fin brown; less pigmented at base and distal margin, forming two faint pale bars and dark central bar. Pelvic fin brown; less pigmented at base and distal margin, forming two faint pale bars and dark central bar, each confluent with bars on body. Anal fin less pigmented at base and distal margin, forming two faint pale bars and dark central bar, each confluent with bars on body.

Barbels and posterior margin of lip pigmented. Oral disk pale. Abdomen pale with moderate amount of pigmentation along sides between pectoral and pelvic fins. Ventral plates pigmented in the same alternating bar pattern as lateral plates.

Adult head and body brown, with some pale mottling ( Fig. 2 ). Juvenile pale bands faded with some remnants present, especially at junction of dorsal and mid-dorsal plate rows. Ventral half of body slightly fainter than dorsal half.

Dorsal fin with four alternating pale and dark bars. Tip of unbranched ray and first branched ray pale, but tips of all other rays dark. Adipose fin spine dark except for pale tip. Distal adipose membrane adjacent to spine pale, otherwise dark. Caudal fin between base and fork with three to four alternating pale and dark bars. Caudal-fin base pale. Bars partially interconnected in holotype ( Fig. 2 ). Caudal-fin tips with additional paledark-pale sequence. Pectoral fin brown, slightly mottled. Pelvic fin with three alternating dark and pale bars. Pelvic-fin base dark. Proximal half of anal fin dark, distal half pale.

Barbels and posterior margin of lip pigmented. Oral disk pale. Abdomen pale with moderate amount of pigmentation along sides between pectoral and pelvic fins. Ventral plates uniformly pale with slight pigmentation.

Sexual dimorphism: In most species of Pseudancistrus , the hypertrophied odontodes along the snout are relatively longer in males than in females ( Armbruster, 2004). This appears to be the case in P. k w i n t i, although the sample size is small.

Range: Pseudancistrus kwinti is only known from the Coppename River drainage, Sipaliwini, Suriname ( Fig. 4 ). These localities are within the Central Suriname Nature Reserve.

Habitat: Pseudancistrus kwinti was collected in rapids ( Fig. 5 ). Substrate was rubble, boulders, and cracked bedrock with patches of the aquatic plant Podostemaceae . Clear water. Swift current.

Etymology: The species-group name, kwinti , refers to the Kwinti people that live along the Coppename River and traditionally fish the area in which the new species was discovered ( Hoogbergen, 1992). The gender of Pseudancistrus is masculine. The species-group name is treated as a noun in apposition.

Figures

FIGURE 1. Dorsal, lateral, and ventral views of juvenile Pseudancistrus kwinti, paratype, FMNH 116975, 43.9 mm SL.

FIGURE 2. Dorsal, lateral, and ventral views of adult Pseudancistrus kwinti, holotype, FMNH 116976, 94.3 mm SL.

FIGURE 3. Mouth of hypothetical Pseudancistrus showing the locations, when present, of the single buccal papilla (BP) and two dentary papillae (DP). The four tooth rows are filled in.

FIGURE 4. Map of major rivers in Suriname and collection localities for Pseudancistrus kwinti (star = holotype, circle = paratype).

FIGURE 5. Holotype locality. Coppename River at base of Sidonkroetoe-val rapids, Central Suriname Nature Reserve, Sipaliwini State, Suriname.

Tables

TABLE 1. Measurements of Pseudancistrus kwinti types (n = 3) in either percent of standard length or percent of head length. Measurements are as described in Armbruster (2003).

(In percent of standard length)
Predorsal length	45.5	45.5–48.3 47.1	1.5
Head length	35.5	35.5–37.1 36.4	0.85
Head–dorsal length	11.3	10.0–11.6 11.0	0.9
Cleithral width	35.7	34.9–37.4 36.0	1.3
Head–pectoral length	30.1	28.5–32.0 30.2	1.7
Thorax length	22.2	22.2–24.9 23.4	1.4
Pectoral-spine length	28.1	26.5–28.1 27.1	0.9
Abdominal length	26.9	22.9–26.9 25.5	2.2
Pelvic-spine length	26.4	25.4–26.7 26.2	0.7
Postanal length	30.1	28.1–31.5 29.9	1.7
Anal-fin spine length	12.8	10.4–12.8 11.7	1.2
Dorsal–pectoral depth	30.3	30.3–32.0 31.4	1.0
Dorsal-spine length	28.1	28.1–30.6 29.0	1.4
Dorsal–pelvic depth	25.4	22.5–26.0 24.6	1.9
Dorsal-fin base length	27.9	27.2–27.9 27.6	0.3
Dorsal–adipose depth	9.8	8.6–13.0 10.4	2.3
Adipose-spine length	11.8	9.8–11.8 10.5	1.1
Adipose–upper caudal depth	14.0	13.4–14.6 14.0	0.6
Caudal peduncle depth	16.3	15.9–16.3 16.2	0.3
Adipose–lower caudal depth	26.4	24.8–26.4 25.9	0.9
Adipose–anal depth	19.3	19.0–21.3 19.9	1.3
Dorsal–anal depth	18.8	17.9–18.8 18.5	0.5
Pelvic–dorsal depth	30.6	29.5–31.0 30.4	0.8
(In percent of head length)
Head–eye length	30.0	30.0–32.2 30.9	1.2
Orbit diameter	16.6	16.6–22.4 18.7	3.2
Snout length	68.0	58.0–68.0 64.2	5.4
Internares width	20.9	12.1–20.9 17.7	4.8
Interorbital width	47.0	32.0–49.8 42.9	9.6
Head depth	70.4	70.4–72.8 71.8	1.3
Mouth length	59.6	52.9–64.2 58.9	5.7
Mouth width	75.9	55.5–75.9 68.1	11.0
Barbel length	9.9	8.5–9.9 9.0	0.8
Dentary tooth cup length	18.4	17.2–18.8 18.1	0.8
Premaxillary tooth cup length	16.6	16.6–18.8 17.7	1.1