New Myloplus from Essequibo River basin, Guyana, with discussion on the taxonomic status of Myleus pacu (Characiformes: Serrasalmidae)

Andrade, Marcelo C.; López-Fernández, Hernán; Liverpool, Elford A.

doi:10.1590/1982-0224-20190026

Acessibilidade / Reportar erro

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Original article • Neotrop. ichthyol. 17 (4) • 2019 • https://doi.org/10.1590/1982-0224-20190026 copy

New Myloplus from Essequibo River basin, Guyana, with discussion on the taxonomic status of Myleus pacu (Characiformes: Serrasalmidae)

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

A new species in the serrasalmid genus Myloplus is described from the middle Mazaruni River, Essequibo River basin, Guyana. The new species is similar to Myleus pacu and Myloplus planquettei in its silver to purplish black coloration and its overall morphology, and has a putative syntopic distribution with those species. The new species is, however, readily distinguishable from the other two by meristic counts of the unpaired fins and by differences in color pattern, primarily in males. Additionally, we provide comments on Myleus pacu and other species that have been confounded under that name.

Keywords:
Endemic; Myletes; Sexually dichromatism; Species inquirenda; Taxonomy

	Holotype	Paratypes			Mean	SD
	CSBD F 3611	ROM 101261	ROM 101262	UMMZ 251911
Standard length (mm)	143.3	145.7	142.4	154.9
Percentages of SL
Body depth	72.7	72.8	78.9	69.1	73.4	4.1
Head length	26.1	25.4	25.8	25.5	25.7	0.3
Distance from snout to supraoccipital spine	33.0	34.5	33.8	34.2	33.9	0.7
Predorsal length	58.3	59.0	60.9	58.5	59.2	1.2
Dorsal-fin base length	36.5	34.6	36.3	36.2	35.9	0.9
Interdorsal length	9.1	10.1	9.0	9.2	9.4	0.5
Adipose-fin base length	4.6	3.7	4.7	4.2	4.3	0.5
Caudal-peduncle length	9.7	9.2	8.9	8.8	9.2	0.4
Caudal-peduncle depth	10.5	10.0	9.9	9.3	9.9	0.5
Caudal peduncle width	3.3	3.4	3.9	3.6	3.6	0.3
Prepectoral length	29.7	28.4	27.9	28.1	28.5	0.8
Pectoral-fin length	21.7	19.9	21.3	20.3	20.8	0.8
Pelvic-fin origin to anal-fin origin	20.4	22.8	21.2	21.8	21.6	1.0
Pectoral-fin origin to pelvic-fin origin	31.6	32.7	37.6	32.6	33.6	2.7
Prepelvic length	60.6	60.8	65.3	60.2	61.7	2.4
Pelvic-fin length	14.7	14.0	14.1	14.1	14.2	0.3
Preanal length	79.0	80.2	75.0	79.3	78.4	2.3
Anal-fin base length	40.4	38.2	41.4	37.7	39.4	1.8
First anal-fin lobe length	20.8	-	24.1	17.7	20.9	3.2
Second anal-fin lobe length	14.3	-	-	16.2	15.3	1.3
Dorsal-fin lobe length	27.1	25.9	28.4	25.3	26.7	1.4
Dorsal-fin origin to anal-fin origin	75.2	74.4	79.5	72.0	75.3	3.1
Dorsal-fin end to anal-fin origin	55.7	54.0	58.8	51.6	55.0	3.0
Dorsal-fin end to anal-fin end	22.2	21.4	21.7	20.5	21.5	0.7
Percentages of HL
Snout length	27.9	28.6	28.3	28.9	28.4	0.4
Mouth length	16.9	16.9	14.7	17.3	16.5	1.2
Mouth width	37.3	35.2	36.7	34.9	36.0	1.2
Interorbital width	55.7	59.0	56.9	53.3	56.2	2.4
Head width	64.8	66.0	67.5	64.7	65.8	1.3
Third infraorbital width	12.5	13.1	12.4	11.8	12.5	0.5
Cheek gap width	8.7	9.0	10.0	10.0	9.4	0.7
Fourth infraorbital width	9.5	10.8	10.6	9.3	10.1	0.8
Eye vertical diameter	47.3	46.6	46.7	45.6	46.6	0.7
Postorbital distance	25.7	25.1	24.4	24.6	25.0	0.6

Sociedade Brasileira de Ictiologia Neotropical Ichthyology, Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura, Universidade Estadual de Maringá., Av. Colombo, 5790, 87020-900, Phone number: +55 44-3011-4632 - Maringá - PR - Brazil
E-mail: neoichth@nupelia.uem.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] Edited by Paulo Lucinda