Cytogenetics of the freshwater cyclopoid mesocyclops longisetus longisetus (crustacea, copepoda) from São Carlos, São Paulo, Brazil

Cytogenetics of the freshwater cyclopoid mesocyclops longisetus longisetus (crustacea, copepoda) from São Carlos, São Paulo, Brazil

William Marcos da Silva^I; Takako Matsumura-Tundisi^II

^IUniversidade Federal do Mato Grosso do Sul, Depto. de Eng. Hidráulica e Transportes. Cx. Postal 549, Cidade Universitária S/N 79070-900-Campo Grande, MS. Email: [e-mail]

^IIInternational Institute of Ecology R. Bento Carlos, 75013560-660 São Carlos, SP Email: [e-mail]

ABSTRACT

A cytogenetic study was carried out on the early embryonic stages of the cyclopoid species Mesocyclops longisetus longisetus (Crustacea, Copepoda) from freshwater environments of the São Carlos area of south-east Brazil. Chromatin was staining using acetic orcein solution. The species showed 2n = 14 chromosomes and presented chromatin diminution in the 4th embryonic cleavage. The eliminated chromatin was concentrated in the equatorial region of the embryonic cell. The results were compared with data for other cyclopoid species of temperate regions.

Key words: Cyclopoida, Mesocyclops longisetus longisetus, cytogenetics, chromatin diminution, chromosomal number.

RESUMO

Realizou-se estudos citogenéticos das fases iniciais da ovogênese da espécie de Cyclopoida Mesocyclops longisetus longisetus (Crustacea, Copepoda) de corpos de água doce de São Carlos, SP, Brasil. A cromatina foi corada com solução de orceína. A espécie apresentou 2n=14 cromossomos e também foi verificado o fenômeno de diminuição de cromatina na 4a clivagem da ovogenêse. A cromatina eliminada concentrou-se na região equatorial das células. Estes resultados são comparados com outras espécies de Cyclopoida de regiões temperadas e também com a mesma espécie registrada na América do Norte. A importância do estudo citogenético para a taxonomia é discutida.

Palavras-chave: Cyclopoida, Mesocyclops longisetus longisetus, citogenética, diminuição de cromatina.

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Date Received : 05/01/04

Revised: 09/03/2004

Accepted: 09/21/2004

ISSN 1676-0611

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Publication Dates

• Publication in this collection
  07 June 2013
• Date of issue
  2004

History

• Accepted
  21 Sept 2004
• Reviewed
  03 Sept 2004
• Received
  01 May 2004