Cyclopoid Copepods (Stellicomitidae) Parasitic on Sea Stars from Madagascar and Eniwetok Atoll

Abstract

Asterocomes indica Padmanabha Rao, 1962, and Stellicomes tumidulus Humes and Cressey, 1958, are recorded from a new host, Halityle regularis, in Madagascar. Stellicomes supplicans sp. n. is described from Asterodiscus elegans, and Leicomes monozotus gen. et sp. n. from Leiaster speciosus, both in Madagascar. Astroxynus culcitae gen. et sp. n. is described from Culcita novaeguineae at Eniwetok Atoll. Stellicomes pambanensis Padmanabha Rao, 1964, is placed in Astroxynus. Stellicomitid copepods, often of minute size, live externally on various asteroid echinoderms. This paper records two new genera and three new species of these crustaceans from Madagascar and Eniwetok Atoll. MATERIALS AND METHODS The copepods were recovered by washing the living sea stars in 5% ethyl alcohol and sea water. The wash water was strained through a fine net (mesh 125 holes per inch) and the copepods picked from the residuum. They were later studied according to the method described by Humes and Gooding (1964). All measurements are given in microns and were made from specimens in lactic acid. The body lengths do not include the setae on the caudal rami. In the spine and setal formulas of legs 1 to 4 the Roman numerals indicate spines and the Arabic numerals represent setae. All figures have been drawn with the aid of a camera lucida. The letter after the explanation of each figure refers to the scale at which it was drawn. The abbreviations used are: A1 = first antenna, A2 = second antenna, MD = mandible, MX1 = first maxilla, MX2 = second maxilla, MXPD = maxilliped, P1 = leg 1, and P2 = leg 2. Asterocomes indica Padmanabha Rao, 1962 Material collected (Madagascar): From Halityle regularis Fisher (new host).-61 specimens from 8 hosts, in 59 to 38 m (trawl), southwest of Isles Mitsio, 13002.5' S, 48021.5' E to 13005.5' S, 48? 20.5' E, 19 June 1967; 2 from 1 host, in 59 to 45 m (trawl), 13002.5' S, 48021.5' E to 13000.5' S, 48? 22.5' E, 19 June 1967. Stellicomes tumidulus Humes and Cressey, 1958 Material collected (Madagascar): From Pentaceraster mammillatus (Audouin).-156 specimens from 3 hosts, in 17 m, near black buoy, north of Pte. Ambarionaomby, Nosy Komba, 5 August 1967; 33 from 7 hosts, in 20 m, in pass between Nosy Komba and Ankify, 5 July 1967; 95 from 16 hosts, Received for publication 20 May 1971. in 10 cm, Ankify (mainland of Madagascar), 10 July 1967; 252 from 1 host, in 18 m, Banc du Touareg, 13?32'05 S, 48?15'20 E, 11 July 1967; 22 from 1 host, in 35 to 30 m (trawl), west of Andilana, 13017.5' S, 48?07' E to 13?16.5' S, 48? 07.8' E, 24 August 1967. From Poraster superbus (Mobius).-25 from 4 hosts, in 59 to 38 m (trawl), southwest of Isles Mitsio, 13?02.5' S, 48021.5' E to 13?05.5' S, 48? 20.5' E, 19 June 1967; 87 from 1 host, in 18 m, Banc du Touareg, 11 July 1967; 93 from 1 host, in 18 m, Banc du Touareg, 11 July 1967. From Halityle regularis Fisher (new host).404 from 8 hosts, in 59 to 38 m (trawl), southwest of Isles Mitsio, 13?02.5' S, 48021.5' E to 13005.5' S, 48?20.5' E, 19 June 1967; 27 from 1 host, in 59 to 45 m (trawl), southwest of Isles Mitsio, 13002.5' S, 48?21.5' E to 1300.5' S, 48022.5' E, 19 June 1967; 56 from 1 host, in 30 m, near Isles Mitsio, 13?05' S, 48?22.5' E to 13005' S, 48?21.5' E, 18 August 1967. Stellicomes supplicans sp. n. (Figs. 1-20) Type material: 1,420 specimens from 2 Asterodiscus elegans Gray, diameter 10 cm, in 59 to 45 m (trawl), southwest of Isles Mitsio, Madagascar, 13?02.5' S, 48?21.5' E to 13?00.5' S, 48?22.5' E, 19 June 1967. Holotype 9, allotype, and 1,050 paratypes deposited in the United States National Museum, Washington (Nos.-holotype 137431, allotype 137432, paratypes 137433); 200 paratypes in the Zoologisch Museum, Amsterdam; the remaining paratypes in the collection of the author. Other specimens: 360 from 1 Asterodiscus elegans, diameter 10 cm, in 59 to 38 m (trawl), southwest of Isles Mitsio, 13?02.5' S, 48?21.5' E to 13?05.5' S, 48?20.5' E, 19 June 1967. Female: Body (Figs. 1-3) ovoid and swollen dorsally. Nonovigerous females with length 405 (390 to 418), greatest width 284 (264 to 297), and thickness 257 (231 to 275), based on 10 specimens. Ovigerous females slightly larger and flatter, length 441 (429 to 455), width 313 (308 to 319), and thickness about 200, based on 3 specimens. Without external segmentation. Large prosome with complex internal sclerotized framework. Urosome small.