Copepoda associated with octocorals in Northwestern Madagascar, including Orecturus sakalavicus n. sp. from the Telestacean Coelogorgia palmosa

Abstract

Several copepods associated with octocorals are recorded from the region of Nosy Be in northwestern Madagascar, including Orecturus sakalavicus n. sp. from Coelogorgia palmosa. The female of this new siphonostomatoid may be distinguished from its four congeners on the basis of selected characteristics as follows: Orecturus grandisetiger (body large, average length 1.20 mm; third segment of antennule with enlarged seta); Orecturus excavatus (outer margin of first segment of exopod excavated, free segment of leg 5 oval); Orecturus forticulus (caudal ramus wider than long, innermost terminal seta on antenna very long and plumose, claw of maxilla stout); and Orecturus finitimus (free segment of leg 5 oval, caudal ramus wider than long). Two poecilostomatoids are reported: Acanthomolgus telestophilus from Coelogorgia palmosa (new host) and Telesticola angoti from Coelogorgia palmosa. Sixty-six species of siphonostomatoid and poecilostomatoid copepods are known to be associated with octocorals, primarily representatives of Gorgonacea, Telestacea, Alcyonacea, and Pennatulacea, in the vicinity of Nosy Be in northwestern Madagascar (Humes, 1982, 1989, 1990; Humes & Stock, 1973). Three poecilostomatoid copepods (but no siphonostomatoids) have been reported from Telestacea in the vicinity of Nosy Be. Acanthomolgus (=Lichomolgus) Telestophilus (Humes & Ho, 1968) occurs with Telesto arborea Wright & Studer, Telesticola angoti Humes & Stock, 1973 lives with Coelogorgia palmosa Milne Edwards & Haime. Paramolgus (=Lichomolgus) clavatus (Humes & Ho, 1968) is known from Coelogorgia palmosa. This paper presents a description of a new siphonostomatoid copepod from Coelogorgia palmosa and lists other copepods from certain alcyonaceans and telestaceans, including new host records. MATERIALS AND METHODS At the time of collection, the colonies of the octocorals were isolated in plastic bags containing sea water. Later, in the laboratory, sufficient 95% ethanol was added to make approximately a 5% solution. After 1-2 h, the octocorals were rinsed, the wash water poured through a fine net (approximately 120 holes per 2.5 cm), and the copepods recovered from the sediment retained. The copepods were measured and studied in lactic acid. Dissections were The copepods were collected in 1963-1964 as part of the United States Program in Biology of the International Indian Ocean Expedition, and in 1967 with the support of a grant from the National Science Foundation (G-5838). The laboratory study has been aided by a grant from the National Science Foundation (BSR 88 21979). TRANS. AM. MICROSC. SOC., 113(2): 117-126. 1994. ? Copyright, 1994, by the American Microscopical Society, Inc. This content downloaded from 207.46.13.51 on Mon, 20 Jun 2016 07:33:01 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC. prepared using the wooden-slide method described by Humes & Gooding (1964). All drawings were made with the aid of a camera lucida.