A new genus of armored catfish (Siluriformes: Loricariidae) from the Greater Amazon, with a review of the species and description of five new species

A new genus of Hypopopomatinae armored catfish is described from the northern portions of South America, namely the Amazon, Orinoco and Guianan coastal drainages. The new genus is diagnosed from all remaining hypoptopomatines by having the canal cheek plate on the ventral surface of the head posteriorly elongated and contacting the cleithrum, in addition to other features that distinguish the new genus from specific genera. Five new species are described and 18 species currently allocated in Parotocinclus, Hisonotus, and Curculionichthys are transferred to the new genus and rediagnosed. Parotocinclus amazonensis and P. aripuanensis are considered junior synonyms of P. britskii. The secondary sexual dimorphism of the members of the new genus is detailed and illustrated. Morphological characters are used to delimit four phenotypic groups of species that might have phylogenetic significance, which still have to be properly tested. A key to the species is offered and diagnoses, illustrations, and distribution maps are provided for all species.

Keywords:
Biodiversity; Identification key; South America; Systematics; Taxonomy

Authorship

Roberto E. Reis

Pontifícia Universidade Católica do Rio Grande do Sul. Av. Ipiranga, 6681, P. O. Box 1429, 90619-900 Porto Alegre, RS, Brazil. (RER) reis@pucrs.br (corresponding author).Pontifícia Universidade Católica do Rio Grande do SulBrazilPorto Alegre, RS, BrazilPontifícia Universidade Católica do Rio Grande do Sul. Av. Ipiranga, 6681, P. O. Box 1429, 90619-900 Porto Alegre, RS, Brazil. (RER) reis@pucrs.br (corresponding author).

https://orcid.org/0000-0003-3746-6894

Pablo Lehmann A.

Laboratório de Ictiologia, Universidade do Vale do Rio dos Sinos. Av. Unisinos, 950, 93022-000 São Leopoldo, RS, Brazil. (PLA) pablole@unisinos.br.Universidade do Vale do Rio dos SinosBrazilSão Leopoldo, RS, BrazilLaboratório de Ictiologia, Universidade do Vale do Rio dos Sinos. Av. Unisinos, 950, 93022-000 São Leopoldo, RS, Brazil. (PLA) pablole@unisinos.br.

https://orcid.org/0000-0002-8884-4827

Edited-by

Marcelo Britto

Correspondence

Roberto E. Reis reis@pucrs.br

Author's Contribution

Roberto E. Reis: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Validation, Writing-original draft, Writing-review and editing.

Pablo Lehmann A.: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Validation, Writing-original draft, Writing-review and editing.

Competing Interests

The authors declare no competing interests.

Ethical Statement

Not applicable.

SCIMAGO INSTITUTIONS RANKINGS

Figures | Tables

Figures (46)
Tables (9)

	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51
*R. britskii*					1	1	3	4	3	8	14	10	15	7	11	12	12	6	3
R. longirostris																		1	3	4	2	1		1		2
R. polyochrus													1									1
R. eppleyi												1	3	1	2	4	1			1
R. variola																							1		1	2	1	2		5		1			1		1				1
R. yaka																								2	2		2		1
R. kwarup																		3	2	2		4	1	1
R. discolor													4	6	5	2
R. pilosus																					3	2	2	4	5		2
R. isabelae											2	3	1	2	2	3		1	1
*R. collinsae*															2		2	2	1	2			2
R. halbolthi																		1	1	1		1
R. hardmanni								1	5	2	4	6
*R. bockmanni*	1	3	3	1
R. dani									2		5	2	1			2		1
R. hera						2	2	1	1	2		2
R. pentakelis					1	1	4	1	7	1		1
R. marginalis		1		3	2	4	1	2
R. loxochelis						1		1		3	3	1
*R. chromodontus*																2	11		1	2		2					1		1	1
R. acuen							1	2		2	4	2
R. jumaorum										1		1			2	1	2	2		1	3		1
R. dinizae						3	1
	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51

Character	R. britskii n = 121						R. longirostris n = 16					R. polyochrus
Character	Hol1	Hol2	Low	High	Mean	SD	Hol	Low	High	Mean	SD	Hol	Para
Standard length (mm)	14.2	22.5	14.2	25.2	20.3		27.5	22.5	28.8	25.3		27.6	26.3
Percent of SL
Body depth	-	-	14.8	19.5	16.9	0.94	18.4	16.4	18.4	17.3	0.61	5.5	4.7
Predosal distance	-	-	43.0	50.1	47.0	1.39	48.7	47.4	51.6	48.9	1.05	12.7	11.9
Prepelvic distance	-	-	39.4	48.6	43.8	1.45	45.4	42.2	45.8	44.0	0.98	12.3	11.2
Preanal distance	-	-	61.0	69.6	65.6	1.51	67.3	65.6	69.6	67.7	1.03	18.6	16.8
Preadipose distance	-	-	73.9	80.8	77.6	1.31	79.1	73.2	80.9	78.2	1.66	21.7	20.1
Dorsal-fin spine length	-	-	21.5	28.4	25.2	1.26	23.7	23.2	26.7	24.6	1.21	7.2	5.9
Anal-fin unbranched ray length	-	-	13.2	20.6	16.7	1.29	14.2	13.8	16.1	15.1	0.75	4.1	3.9
Adipose-fin spine length	1.1	-	6.0	9.3	7.8	0.68	-	6.9	9.3	8.1	0.59	2.3	2.2
Pectoral-fin spine length	4.1	6.0	25.8	33.7	29.0	1.35	30.7	29.2	33.0	30.8	1.13	8.9	7.7
Caudal peduncle depth	1.4	1.8	7.1	10.0	8.6	0.53	7.2	6.8	7.9	7.4	0.36	2.0	1.8
Dorsal-adipose fin distance	-	-	16.2	20.5	18.5	1.01	-	18.6	21.5	19.6	0.86	5.4	5.1
Dorsal-fin base length	-	-	9.6	14.5	12.5	0.93	-	9.7	13.4	12.5	1.10	3.5	3.0
Lower caudal-fin principal ray	-	-	22.3	33.2	27.4	2.29	-	21.2	30.0	26.3	2.64	-	6.7
Cleithral width	4.3	5.9	24.5	30.4	26.9	0.88	27.3	26.1	28.2	26.9	0.55	7.7	7.3
Head length	5.7	7.8	34.3	40.2	37.0	1.30	37.4	36.2	39.7	38.3	1.03	10.4	10.1
Percent of HL
Head depth	-	-	39.8	50.4	44.8	2.35	44.8	41.9	46.7	43.9	1.53	5.1	4.6
Interorbital distance	1.8	2.5	29.7	39.1	33.8	1.76	32.6	31.9	35.4	33.2	1.05	4.1	3.5
Orbital horizontal diameter	1.0	1.2	15.0	20.3	17.2	0.95	14.5	14.5	16.4	15.4	0.55	1.6	1.4
Snout length	2.8	4.0	47.2	55.4	52.1	1.62	56.3	55.7	58.3	56.7	0.77	5.6	5.4
Internarial distance	5.7	7.8	4.7	11.3	8.6	1.11	8.4	8.4	11.0	9.5	0.70	1.2	1.0
Tooth count
Premaxilla	12	-	15	29	23.3	3.18	-	28	36	31.1	2.56	23	32
Dentary	14	-	15	29	22.2	3.08	-	27	31	29.1	1.33	31	27

Character	R. eppleyi n = 16				R. variola n = 18				R. yaka n = 14
Character	Low	High	Mean	SD	Low	High	Mean	SD	Hol	Low	High	Mean	SD
Standard length (mm)	19.4	28.1	23.1		19.5	30.0	23.6		29.4	17.9	30.06	24.0
Percent of SL
Body depth	14.7	19.1	16.4	1.34	16.2	20.0	17.9	1.18	15.9	14.0	17.2	15.9	0.89
Predosal distance	45.6	50.3	48.2	1.28	46.6	51.0	49.0	1.13	47.8	46.3	51.3	48.2	1.68
Prepelvic distance	42.7	49.0	45.8	1.69	42.7	47.9	45.1	1.44	43.7	41.8	51.2	44.6	2.30
Preanal distance	65.0	70.5	67.0	1.49	66.7	70.8	68.0	1.12	66.1	64.4	68.6	66.1	1.22
Preadipose distance	74.6	80.7	77.2	1.85	75.9	81.3	78.3	1.37	79.3	75.0	79.3	77.0	1.37
Dorsal-fin spine length	21.0	25.2	23.0	1.37	23.6	27.0	25.2	1.02	24.3	20.0	25.9	24.3	1.60
Anal-fin unbranched ray length	13.1	15.0	14.0	0.73	13.8	16.7	14.9	0.82	13.5	12.8	16.7	14.7	1.04
Adipose-fin spine length	7.7	11.1	8.8	1.07	6.4	8.4	7.2	0.53	7.5	6.1	8.3	7.2	0.68
Pectoral-fin spine length	29.0	31.2	30.0	0.67	30.2	34.0	32.1	1.15	27.8	26.4	31.4	29.2	1.36
Caudal peduncle depth	6.9	7.8	7.3	0.30	6.8	7.8	7.2	0.28	6.9	6.8	8.1	7.4	0.35
Dorsal-adipose fin distance	16.5	19.5	18.1	1.03	13.5	19.1	16.5	1.63	16.8	13.1	17.8	16.2	1.16
Dorsal-fin base length	9.8	14.2	12.5	1.25	11.7	15.5	13.6	1.02	13.2	10.3	14.1	12.5	1.06
Lower caudal-fin principal ray	20.5	25.8	23.2	1.85	22.8	27.2	25.0	1.20	23.3	23.3	28.2	25.9	1.49
Cleithral width	24.8	28.0	26.0	0.82	27.7	30.8	28.9	0.90	26.0	25.5	27.9	26.5	0.57
Head length	38.0	42.6	39.2	1.34	37.5	41.7	39.5	1.10	35.5	35.4	42.2	38.4	2.41
Percent of HL
Head depth	37.5	43.1	40.7	1.61	36.9	48.7	43.6	3.22	45.3	37.3	46.4	42.6	3.27
Interorbital distance	29.6	36.1	32.1	1.84	32.0	37.0	34.5	1.42	36.8	32.2	38.6	35.6	1.85
Orbital horizontal diameter	14.7	17.1	15.8	0.72	15.5	17.5	16.4	0.51	15.4	15.0	17.8	16.4	0.76
Snout length	52.4	56.8	54.7	1.14	55.2	57.7	56.6	0.86	55.4	53.3	56.5	54.9	0.92
Internarial distance	6.7	10.3	8.8	1.19	8.2	11.7	9.5	0.79	10.0	6.3	10.1	8.2	1.21
Tooth count
Premaxilla	22	30	25.1	2.14	33.0	51.0	39.8	4.49	39	34	39	35.9	1.86
Dentary	21	27	24.1	1.80	33.0	43.0	36.7	2.75	41	31	41	35.7	3.74

Character	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

Character	R. collinsae n = 20					R. halbothi n = 12					R. hardmani n = 19
Character	Hol	Low	High	Mean	SD	Hol	Low	High	Mean	SD	Hol	Low	High	Mean	SD
Standard length (mm)	23.9	18.0	24.2	22.1		19.4	17.5	19.9	18.8		22.7	20.3	24.3	22.6
Percent of SL
Body depth	16.2	16.0	17.9	16.8	0.68	15.9	14.7	19.5	16.3	1.14	16.5	13.8	16.6	15.3	0.87
Predosal distance	49.1	49.1	52.5	51.0	0.97	51.3	51.0	55.5	53.0	1.38	50.4	50.1	53.7	51.8	1.11
Prepelvic distance	48.0	45.4	49.3	47.8	1.27	50.5	45.9	54.6	50.0	2.10	49.1	48.1	51.0	49.6	0.85
Preanal distance	67.9	66.9	69.3	68.0	0.87	70.4	66.2	75.2	69.6	2.43	68.3	66.2	70.4	68.6	1.27
Preadipose distance	81.6	81.0	84.5	82.4	0.89	79.7	78.1	86.0	80.7	2.27	81.2	77.9	82.4	80.7	1.23
Dorsal-fin spine length	19.5	17.6	22.0	20.0	1.28	19.9	17.8	21.6	20.0	1.13	19.0	16.4	19.7	18.7	0.80
Anal-fin unbranched ray length	15.1	12.6	15.4	14.1	0.96	13.2	13.0	17.3	14.9	1.22	15.6	12.6	15.8	14.2	0.93
Adipose-fin spine length	5.6	5.5	7.7	6.5	0.83	5.3	4.5	7.2	5.4	0.90	4.6	3.4	5.4	4.5	0.57
Pectoral-fin spine length	24.6	23.3	27.9	25.0	1.31	19.4	19.4	24.3	21.9	1.44	24.2	22.9	26.9	25.2	0.97
Caudal peduncle depth	9.5	9.4	10.4	9.8	0.32	9.1	9.0	10.3	9.6	0.46	8.8	8.2	9.1	8.7	0.30
Dorsal-adipose fin distance	19.6	17.8	19.7	19.1	0.66	16.7	14.3	21.1	17.0	1.71	16.1	16.1	18.5	17.3	0.62
Dorsal-fin base length	12.3	10.1	13.0	11.9	0.83	15.1	12.1	15.1	13.1	0.81	11.5	11.3	13.5	12.2	0.73
Lower caudal-fin principal ray	26.2	21.4	26.4	24.3	1.68	23.7	21.9	26.5	24.2	1.31	24.1	19.0	27.7	24.0	1.88
Cleithral width	26.6	25.4	29.0	26.9	0.99	29.4	28.1	31.3	29.1	0.83	22.9	21.8	23.8	22.7	0.57
Head length	38.6	38.1	42.2	39.9	1.35	41.9	38.9	44.4	42.0	1.36	40.4	38.1	42.8	40.7	1.43
Percent of HL
Head depth	43.4	40.2	44.5	42.3	1.48	38.9	38.5	48.5	41.0	2.63	38.2	35.3	39.1	37.8	1.13
Interorbital distance	29.7	26.6	30.5	28.8	1.05	29.9	27.1	33.6	29.6	1.53	24.1	21.9	25.0	23.9	0.79
Orbital horizontal diameter	12.6	12.3	14.2	13.0	0.53	12.6	11.1	16.1	12.9	1.38	12.8	11.1	14.4	13.2	1.10
Snout length	57.5	56.4	58.9	57.7	0.87	58.0	57.8	65.6	60.0	2.54	59.5	56.0	60.6	58.8	1.36
Internarial distance	8.7	6.3	9.5	7.9	1.17	10.0	7.6	11.0	9.0	1.05	6.8	5.6	7.8	6.7	0.62
Tooth count
Premaxilla	33	25	33	28.6	2.73	30	28	32	29.8	1.71	21	18	22	20.5	1.38
Dentary	32	24	32	26.5	2.70	30	26	30	27.7	1.80	18	16	19	17.6	0.98

Character	R. bockmanni n = 8				R. dani n = 14					R. hera n = 10
Character	Low	High	Mean	SD	Hol	Low	High	Mean	SD	Hol	Low	High	Mean	SD
Standard length (mm)	18.3	23.0	19.8		27.4	20.4	27.4	24.1		25.2	19.4	26.1	22.6
Percent of SL
Body depth	17.2	22.2	20.0	1.89	17.3	16.3	18.3	17.1	0.58	15.8	14.6	17.5	16.0	0.93
Predosal distance	47.5	51.2	49.3	1.21	48.6	47.5	49.8	48.4	0.77	49.0	47.2	50.5	48.6	0.92
Prepelvic distance	44.4	47.3	45.9	1.08	45.3	43.7	45.7	44.8	0.56	44.4	43.3	47.4	44.7	1.53
Preanal distance	64.7	67.6	66.0	0.92	65.1	63.8	66.1	65.1	0.69	64.8	63.4	67.0	64.4	1.13
Preadipose distance	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Dorsal-fin spine length	24.2	28.3	26.1	1.56	24.0	24.0	27.0	25.3	0.90	25.1	21.5	25.1	23.7	1.13
Anal-fin unbranched ray length	18.2	21.3	19.0	1.09	15.5	15.5	19.3	16.6	1.07	18.3	14.4	18.3	16.7	1.30
Adipose-fin spine length	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Pectoral-fin spine length	29.3	31.6	30.3	0.74	29.8	29.2	31.8	30.4	0.82	29.8	27.6	29.9	28.9	0.88
Caudal peduncle depth	10.6	11.6	11.1	0.37	8.8	8.8	9.9	9.3	0.28	8.3	7.8	9.3	8.6	0.50
Dorsal-adipose fin distance	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Dorsal-fin base length	11.8	14.3	13.1	0.75	11.3	9.8	12.7	11.5	0.87	9.3	9.3	12.3	10.3	1.08
Lower caudal-fin principal ray	28.4	34.1	31.0	1.96	-	24.3	27.9	26.4	1.12	25.3	24.3	29.7	26.7	1.93
Cleithral width	24.2	26.7	25.4	0.91	23.6	23.6	26.5	25.3	0.91	24.5	23.6	26.0	24.6	0.72
Head length	38.4	41.6	39.9	0.98	38.3	36.3	40.0	38.2	1.1	37.6	35.1	41.2	38.5	1.95
Percent of HL
Head depth	41.3	45.4	43.0	1.57	42.9	39.9	43.5	42.4	0.9	42.8	39.9	45.5	42.2	1.97
Interorbital distance	32.7	36.1	34.4	1.23	39.2	36.2	41.9	38.7	1.6	36.4	33.7	37.7	35.4	1.37
Orbital horizontal diameter	16.2	18.6	17.5	0.86	14.6	13.6	16.7	15.3	0.8	16.6	15.1	17.3	16.5	0.68
Snout length	49.0	52.2	50.3	1.07	53.1	50.8	55.6	52.7	1.2	52.8	51.9	55.6	53.5	1.40
Internarial distance	6.6	10.7	8.6	1.26	11.0	9.6	12.0	11.0	0.7	9.8	7.2	11.2	9.9	1.22
Tooth count
Premaxilla	11	14	12.5	0.93	26	19	28	21.9	2.7	20	16	22	18.7	2.26
Dentary	9	12	11.0	1.07	22	16	22	19.4	1.7	21	15	21	17.4	2.01

Character	R. pentakelis n = 16				R. marginalis n = 13					R. loxochelis n = 9
Character	Low	High	Mean	SD	Hol	Low	High	Mean	SD	Hol	Low	High	Mean	SD
Standard length (mm)	18.1	23.6	21.2		19.6	18.2	20.8	19.4		22.6	20.3	23.1	21.6
Percent of SL
Body depth	18.4	20.8	19.5	0.80	17.7	16.5	18.7	17.9	0.62	18.7	18.3	20.4	19.4	0.70
Predosal distance	47.1	49.5	48.1	0.79	47.8	43.6	49.8	47.7	1.45	50.0	48.7	52.8	50.5	1.55
Prepelvic distance	42.0	45.2	43.6	0.83	45.2	43.1	46.7	44.7	1.11	44.1	42.8	46.4	44.3	1.19
Preanal distance	62.4	66.6	64.3	1.20	62.9	56.4	65.1	62.9	2.22	65.0	61.7	66.2	63.9	1.27
Preadipose distance	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Dorsal-fin spine length	27.0	30.8	28.8	1.24	23.1	21.9	25.7	24.1	1.18	25.7	23.2	27.6	25.4	1.29
Anal-fin unbranched ray length	18.4	21.8	19.7	0.90	18.0	17.0	19.9	18.6	0.77	17.3	17.1	19.0	18.0	0.73
Adipose-fin spine length	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Pectoral-fin spine length	28.8	33.5	30.6	1.23	28.7	28.3	30.3	29.2	0.58	32.1	30.4	32.1	31.2	0.63
Caudal peduncle depth	10.1	11.7	10.7	0.42	9.2	9.3	10.0	9.6	0.23	10.5	10.3	11.2	10.8	0.31
Dorsal-adipose fin distance	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Dorsal-fin base length	11.1	13.1	12.5	0.46	12.1	11.4	12.4	12.0	0.27	11.9	11.8	13.5	12.6	0.66
Lower caudal-fin principal ray	26.9	34.6	29.9	1.88	27.4	27.4	31.5	29.0	1.37	27.4	24.5	29.2	27.0	1.51
Cleithral width	25.4	27.5	26.2	0.53	25.6	24.6	27.2	25.8	0.67	26.2	26.1	27.4	26.8	0.50
Head length	37.5	39.7	38.3	0.61	39.2	38.0	40.8	39.3	0.97	39.3	39.3	42.1	40.4	0.79
Percent of HL
Head depth	43.6	49.5	47.1	1.70	45.2	40.2	46.1	44.0	1.83	49.4	44.3	49.4	46.8	1.75
Interorbital distance	36.9	40.9	39.1	0.94	34.8	34.8	37.6	36.1	0.86	42.3	38.8	43.9	42.1	1.46
Orbital horizontal diameter	15.9	18.2	16.7	0.62	16.7	14.9	17.5	16.2	0.72	17.5	15.9	18.1	17.3	0.63
Snout length	49.2	53.3	51.0	1.05	51.4	47.9	53.1	50.7	1.27	50.0	49.4	52.3	51.0	0.98
Internarial distance	7.6	12.3	9.7	1.55	12.4	8.2	13.2	11.1	1.30	14.4	11.8	14.4	13.0	0.80
Tooth count
Premaxilla	15	22	18.3	1.69	14	12	18	15.5	1.71	20	16	22	19.9	1.83
Dentary	14	21	16.8	1.81	13	11	16	13.3	1.25	17	15	19	16.9	1.27

Character	R. chromodontus n = 11					R. acuen n = 11					R. jumaorum n = 14					R. dinizae n = 4
Character	Hol	Low	High	Mean	SD	Hol	Low	High	Mean	SD	Hol	Low	High	Mean	SD	Low	High	Mean	SD
Standard length (mm)	26.2	23.3	32.2	26.9		25.8	22.3	27.4	25.2		26.3	24.4	31.0	27.0		17.8	20.0	19.0
Percent of SL
Body depth	17.9	17.0	18.9	17.9	0.61	19.7	16.6	19.7	17.7	1.00	15.2	14.7	17.9	16.1	0.96	15.8	16.8	16.4	0.47
Predosal distance	47.3	47.0	51.4	48.6	1.32	50.1	47.5	50.1	48.8	0.78	48.1	47.8	50.9	49.1	1.11	46.9	49.5	48.5	1.13
Prepelvic distance	41.6	40.9	45.3	43.2	1.59	44.1	42.9	46.5	44.1	1.08	44.3	42.0	45.2	43.9	0.82	44.9	46.6	45.7	0.82
Preanal distance	61.8	61.8	66.4	64.2	1.35	63.8	62.4	65.2	63.8	1.12	65.7	62.7	65.7	64.1	0.87	63.6	65.5	64.3	0.84
Preadipose distance	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Dorsal-fin spine length	22.1	18.5	23.2	20.8	1.60	20.0	20.0	22.8	21.3	0.94	21.7	20.4	23.9	21.8	0.87	22.8	25.5	24.1	1.28
Anal-fin unbranched ray length	16.0	13.5	17.0	15.1	0.97	15.4	15.0	17.4	16.3	0.83	16.5	15.3	18.2	16.8	0.67	18.5	19.5	19.0	0.44
Adipose-fin spine length	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Pectoral-fin spine length	26.8	26.7	29.5	27.8	0.88	24.9	23.1	26.9	24.7	0.98	25.1	23.3	26.7	24.8	1.01	28.1	30.0	29.1	0.83
Caudal peduncle depth	9.5	8.9	9.8	9.4	0.27	9.7	8.5	10.5	9.5	0.54	8.6	8.4	9.5	8.9	0.34	8.9	9.5	9.1	0.27
Dorsal-adipose fin distance	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Dorsal-fin base length	-	10.6	14.2	12.4	1.03	-	11.6	13.5	12.6	0.59	10.8	9.6	11.1	10.4	0.39	11.0	12.8	12.0	0.88
Lower caudal-fin principal ray	27.2	23.2	28.4	25.1	1.85	-	22.7	27.3	25.7	1.34	-	22.8	28.4	25.4	1.93	27.1	29.7	28.1	1.14
Cleithral width	25.2	24.9	27.9	26.5	1.03	24.1	21.7	24.1	22.9	0.71	24.4	22.4	24.9	23.8	0.75	22.5	23.8	23.0	0.56
Head length	36.3	36.2	38.5	37.1	0.74	40.0	37.0	40.0	38.6	0.89	36.8	36.4	39.7	37.8	1.18	40.0	41.8	41.0	0.75
Percent of HL
Head depth	45.4	40.8	50.1	46.8	2.88	45.1	41.2	45.1	42.8	1.27	41.3	38.5	43.6	41.2	1.70	37.8	42.4	39.7	2.11
Interorbital distance	37.1	33.9	37.4	36.1	1.05	35.2	34.9	38.7	36.0	1.09	35.6	32.1	37.9	35.1	1.98	33.8	36.2	35.0	1.08
Orbital horizontal diameter	13.1	11.5	13.7	12.8	0.63	14.0	13.0	15.5	13.9	0.73	14.0	12.8	15.0	13.9	0.67	12.9	14.8	13.8	0.78
Snout length	55.4	53.4	57.4	55.2	1.23	53.0	53.0	56.1	55.0	1.16	57.7	55.5	59.8	57.4	1.12	52.9	54.3	53.7	0.62
Internarial distance	8.8	6.2	13.1	8.8	2.19	9.8	8.2	9.9	9.2	0.54	11.6	9.9	13.7	11.5	0.96	7.3	11.3	10.1	1.88
Tooth count
Premaxilla	29	26.0	40.0	31.6	5.01	22	17	22	20.1	1.70	28	20.0	33.0	27.4	3.67	16.0	17.0	16.3	0.50
Dentary	25	21.0	34.0	26.8	3.74	18	14	19	16.5	1.75	25	18.0	28.0	23.3	3.02	12.0	14.0	13.3	0.96