Rhinotocinclus kwarup ( Lehmann & Reis, 2021 ), 2022

Reis, Roberto E. & Lehmann A., Pablo, 2022, A new genus of armored catfish (Siluriformes: Loricariidae) from the Greater Amazon, with a review of the species and description of five new species, Neotropical Ichthyology (e 220002) 20 (2), pp. 1-100 : 40-42

Rhinotocinclus kwarup ( Lehmann & Reis, 2021) , new combination

( Fig. 25 ; Tab. 5 )

Parotocinclus kwarup Lehmann & Reis, 2021:449 (Type-locality: Couto de Magalhães River near Vila São José do Couto, Campinápolis, MT, Brazil [13°50’17”S 53°03’53”W]. Holotype: MZUSP 125830).

Diagnosis. Rhinotocinclus kwarup is distinguished from R. acuen , R. bockmanni , R. chromodontus , R. dani , R. dinizae , R. hera , R. jumaorum , R. pentakelis , R. marginalis n. sp., and R. loxochelis n. sp. by possessing an adipose fin (vs. adipose fin absent), and by having a Y-shaped light mark from the snout tip to each nostril (Figs. 6A,B; vs. light mark V-shaped or present as two separate lines from snout tip diverging to each nostril). It is distinguished from R. collinsae , R. halbolthi , and R. hardmanni by lacking accessory teeth on both premaxilla and dentary (Figs. 5B,C; vs. accessory teeth present, Fig. 5A); the odontodes on the ventral surface of first pelvic-fin ray bent and pointing mesially (Fig. 9A; vs. odontodes aligned with main ray axis, Fig. 9B); a triangular dark spot on the anterior portion of the dorsal-fin membrane (Fig. 8B; vs. dorsal-fin spot absent); a Y-shaped light mark from snout tip to nostrils (vs. Y-shaped light mark absent); and a larger orbit, 31.2–40.5% snout length (vs. orbit 18.9–24.6% snout length). Rhinotocinclus kwarup is distinguished from R. discolor n. sp., R. eppleyi , R. isabelae n. sp., R. longirostris , R. pilosus n. sp., R. polyochrus , R. variola , and R. yaka by having the snout more broadly rounded (Fig. 11A; vs. snout more acutely pointed, Fig. 11B); dark bars on body narrower and more widely spaced (Fig. 7A; vs. dark bars on body wider and closer together, Fig. 7B); and one plate between the posterior border of the rostral plate and the nostril (Fig. 12B; vs. 2–4 plates). It is distinguished from R. britskii by having more numerous premaxillary, 28–34 (mode 32), and dentary, 27–33 (mode 29) teeth (vs. fewer premaxillary and dentary teeth, 15–29 (modes 23 and 20/25 respectively), see Tabs. 1–2 ; and by having the color pattern with more broken marks, mottled (vs. color pattern with less broken marks).

Geographical distribution. Rhinotocinclus kwarup occurs in the tributaries of the upper rio Xingu in the state of Mato Grosso, Brazil ( Fig. 15 ).

Remarks. Rhinotocinclus kwarup , from the upper rio Xingu basin, is most similar to R. bristkii . The morphological differences found between these two species are the color pattern, which has more broken marks, creating a mottled appearance in the former, while R. britskii has the body bars and head marks more unbroken, causing a clearer pattern, and the number of oral teeth, as R. kwarup has 28–34 (mode 32) premaxillary and 27–33 (mode 29) dentary teeth, while all analyzed populations of R. britskii have 15–29 (mode 23) premaxillary and 15–29 (mode 20 and 25) dentary teeth, see Tabs. 1 and 2 for tooth count distribution. These counts are not fully discrete and partially overlap, and this species should probably be included in a wide molecular assessment of P. britskii populations. Rhinotocinclus kwarup was tentatively categorized as Least Concern (LC) by Lehmann, Reis (2021) in the original description.

Material examined. Rio Xingu basin, Mato Grosso State, Brazil: MZUSP 125830 , holotype (measured) and MZUSP 95576 , 61 paratypes (8 measured), rio Couto de Magalhães near Vila São José do Couto , Campinápolis, 13°50’17”S 53°03’53”W. LBP 15894 , 6 paratypes, creek tributary to rio Coluene , Canarana, 13°25’30.9”S 52°16’47.0”W . MCP 32146 , 3 paratypes, rio Von der Stainer (= rio Atelchu) on road from Santa Terezinha to Iberê, ca. 28 km W of Iberê , Nova Ubiratã, 12°47’05”S 54°40’49”W . MCP 32296 , 12 + 3 cs paratypes, rio Arraias on road from Vera to Feliz Natal, ca. 5 km NW of Feliz Natal , Mato Grosso, 12°21’46”S 54°57’30”W. MCP 32297 , 32 (5 measured) + 3 cs paratypes, rio Azul on road MT-140, ca. 7 km NNW of Santa Carmen , 11°54’42”S 55°17’48”W. MCP 32298 , 2 paratypes, creek on road from Santa Terezinha to Iberê , ca. 10 km W of Iberê, Nova Ubiratã, 12°45’19”S 54°34’25”W . MCP 32299 , 2 paratypes, creek tributary to rio Azul on road MT-423 , ca. 51 km SW of Cláudia, Sinop, 11°40’17”S 55°12’54”W . MCP 32300 , 1 paratype, córrego Etnéia on road MT-423 , ca. 60 km SW of Cláudia, Sinop, 11°42’21”S 55°17’03”W. MCP 32301 , 1 paratype, creek tributary to rio da Saudade on road MT-423 ca. 38 km SE of Marcelândia , Analândia do Norte, 11°13’23”S 54°17’24”W. MCP 32302 , 1 paratype, rio Ferro on road from Novo Mato Grosso to Nova Ubiratã , ca. 25 km SW of Novo Mato Grosso, Nova Ubiratã, 13°03’32”S 55°02’12”W. MCP 39805 , 1 cs paratype, córrego da Caporã, tributary to córrego Três Marias, rio Suiazinho, on road BR-158 , Ribeirão Cascalheira, 12°32’10”S 51°46’45”W . MNRJ 24970 , 64 paratypes, ribeirão das Traíras, tributary to rio Comandante Fontoura on road BR-158, S of Posto da Mata , Alto Boa Vista, 11°49’43”S 51°38’09”W . MNRJ 25073 , 1 paratype, córrego Trinta , Alô Brasil, 12°14’54”S 51°42’45”W . MNRJ 25138 , 2 paratypes, ribeirão Bonito, tributary to rio Suiazinho , Ribeirão Cascalheira, 12°57’09”S 51°51’07”W. MZUSP 95679 , 9 paratypes, ribeirão da Anta and marginal pool in its mouth into rio Culuene , Gaúcha do Norte, 13°30’53”S 53°05’34”W . MZUSP 95709 , 21 paratypes (6 measured), rio Coronel Vandick , ca. 20 km of Vila do rio Culuene, Gaúcha do Norte, 13°31’34”S 52°43’52”W . MZUSP 97040 , 89 paratypes, rio Couto de Magalhães at mouth of córrego Água Clara, Meu Ranchinho Farm , Campinápolis, 13°48’02”S 53°03’43”W. MZUSP 97068 , 51 paratypes, córrego Água Fria, tributary to rio Couto de Magalhães , ca. 2.5 km S of Vila São José do Couto, Campinápolis, 13°49’25”S 53°04’30”W . MZUSP 99007 , 3 paratypes, rio Von den Steinen (= rio Atelchu) at Fazenda A.R.S. , Nova Ubiratã, 13°05’35”S 54°49’08”W. MZUSP 99060 , 4, rio Couto de Magalhães at Airton Espirito Santo Farm, Campinápolis, 13°55’16”S 53°01’27”W.

Figures

FIGURE 15 | Geographical distribution of Rhinotocinclus species of the R. britskii group in central and northwestern South America. Rhinotocinclus britskii (white dots); R. discolor n. sp. (purple dots); R. eppleyi (orange dots); R. isabelae n. sp. (pink dots); R. kwarup (red dots); R. longirostris (blue dots); R. pilosus n. sp. (yellow dots); R. polyochrus (cyan dot); R. variola (black dots); R. yaka (light green dots). T = Type-locality; T1 = type-locality of Parotocinclus britskii, T2 = type-locality of P. amazonensis, T3 = type-locality of P. aripuanensis.

FIGURE 25 | Rhinotocinclus kwarup, holotype, MZUSP 125830, 21.6 mm SL, female, rio Couto de Magalhães near Vila São José do Couto, Campinápolis, Mato Grosso, Brazil.

Tables

TABLE 5 | Descriptive morphometrics of Rhinotocinclus species. Values given as percent of standard length or head length. Range includes the holotype (Hol), SD = standard deviation.

		R. kwarup n=20					R. discolor n=20					R. pilosus n=20					R. isabelae n=15
Character
	Hol	Low	High	Mean	SD	Hol	Low	High	Mean	SD	Hol	Low	High	Mean	SD	Hol	Low	High	Mean	SD
Standard length (mm)	21.6	18.8	23.7	21.3		24.4	21.6	25.2	23.3		22.6	18.1	22.6	20.2		17.6	14.6	17.9	16.6
Percent of SL
Body depth	15.1	13.6	17.2	15.7	0.88	16.2	16.2	18.7	17.2	0.71	16.9	15.4	18.9	17.3	0.84	19.9	17.8	20.9	19.4	0.85
Predosal distance	44.5	44.5	48.4	46.7	1.11	46.6	46.2	50.3	47.7	1.13	48.6	47.8	51.4	49.8	1.00	48.8	45.7	50.9	48.6	1.48
Prepelvic distance	42.4	40.6	44.9	42.5	0.98	42.6	42.1	46.0	43.8	1.17	45.1	44.1	48.2	46.3	1.05	44.3	41.1	48.4	45.3	1.75
Preanal distance	65.5	62.2	67.5	65.2	1.40	64.6	63.6	67.1	65.4	1.03	68.6	65.9	71.8	69.1	1.36	66.8	64.3	69.7	67.1	1.80
Preadipose distance	78.2	72.3	80.0	76.7	1.65	75.6	74.1	78.3	76.2	1.04	78.4	75.4	80.3	78.3	1.22	74.8	74.8	79.8	77.0	1.39
Dorsal-fin spine length	23.7	20.5	27.7	24.0	1.59	25.3	23.2	25.3	24.1	0.62	24.2	21.1	25.3	23.1	0.92	25.1	22.6	26.0	24.4	0.86
Anal-fin unbranched ray length	16.0	12.1	17.1	14.8	1.12	15.6	13.5	17.3	16.1	0.80	13.6	12.4	16.4	14.4	1.01	17.1	16.6	20.4	18.1	0.99
Adipose-fin spine length	7.2	5.3	8.4	7.1	0.74	8.6	7.6	10.3	8.5	0.82	6.1	6.0	7.9	6.7	0.51	7.4	7.0	9.4	8.0	0.59
Pectoral-fin spine length	28.4	23.9	29.6	26.6	1.62	26.9	24.8	27.3	26.4	0.65	28.4	24.7	29.8	27.1	1.24	29.2	27.9	30.2	29.2	0.62
Caudal peduncle depth	8.3	7.3	8.6	7.9	0.35	7.7	7.7	8.6	8.2	0.25	6.4	6.3	7.5	6.7	0.30	8.1	8.1	8.8	8.5	0.24
Dorsal-adipose fin distance	20.0	18.9	20.9	19.8	0.52	16.6	13.3	18.1	16.0	1.51	16.7	12.8	17.5	15.2	1.49	14.4	12.3	16.5	14.7	1.45
Dorsal-fin base length	12.2	9.5	12.7	11.3	0.93	11.8	10.1	12.9	12.0	0.69	12.7	11.2	14.7	12.3	1.01	12.9	11.6	13.7	12.6	0.59
Lower caudal-fin principal ray	23.9	21.1	28.7	25.0	1.81	28.4	25.2	29.7	27.5	1.35	24.0	21.3	27.3	23.7	1.32	27.4	23.4	29.1	27.4	1.43
Cleithral width	27.5	24.4	27.5	26.0	0.97	26.6	26.5	28.3	27.2	0.52	27.3	27.2	29.0	28.0	0.51	31.6	29.5	31.6	30.5	0.56
Head length	35.3	32.4	37.4	35.4	1.60	37.0	36.8	39.3	37.8	0.72	38.9	38.9	43.1	41.7	0.97	40.2	39.4	42.7	40.8	1.05
Percent of HL
Head depth	43.6	41.2	48.0	44.4	1.90	42.1	39.5	48.4	42.8	2.61	41.7	36.2	43.0	39.9	1.66	47.2	46.4	50.8	48.6	1.30
Interorbital distance	37.1	31.9	37.7	35.3	1.76	30.9	28.7	34.4	31.0	1.45	36.7	32.0	36.7	33.5	1.12	34.5	33.0	36.3	34.9	1.02
Orbital horizontal diameter	18.8	16.8	21.3	18.6	1.36	18.1	15.4	19.7	17.7	1.23	18.4	15.0	18.9	16.8	0.95	16.5	15.8	17.8	16.8	0.63
Snout length	52.4	50.0	55.8	53.0	1.30	52.7	49.7	58.5	53.0	2.41	57.3	53.4	57.3	55.1	1.11	52.5	51.5	54.7	53.3	1.03
Internarial distance	9.1	6.4	10.4	8.5	0.99	8.3	7.7	10.8	9.0	0.85	11.1	8.6	11.8	10.1	0.95	10.3	9.6	11.6	10.7	0.55
Tooth count
Premaxilla	-	28	34	30.2	2.13	24	23	26	24.3	0.99	35	31	37	33.8	1.81	22	21.0	29.0	24.3	2.46
Dentary	-	27	33	29.8	1.66	24	19	24	21.9	1.58	34	29	35	31.8	1.96	20	18.0	24.0	21.5	2.20