CHORDARIACEAE, Greville, 1830

Coppejans, Eric, Leliaert, Frederik, Verbruggen, Heroen, de Clerck, Olivier, Schils, Tom, de Vriese, Thomas & Marie, Daniel, 2004, The marine green and brown algae of Rodrigues (Mauritius, Indian Ocean), Journal of Natural History 38 (23), pp. 2959-3020 : 3004-3005

CHORDARIACEAE Cladosiphon Kützing

Four species of Cladosiphon occur in the Indian Ocean: C. filum (Harvey) Kylin , C. mauritianus Børgesen , C. occidentalis Kylin and C. vermicularis (J. Agardh) Kylin ( Silva et al., 1996: 616–617) . A synthesis of their morphological and anatomical characters is given in table 3.

After comparison of the above-mentioned characters it appears that the material from Rodrigues belongs to Cladosiphon mauritianus . Nevertheless, it should be emphasized that C. occidentalis and C. mauritianus are very similar. Further research should clarify if they are two different species or if they have to be

synonymized.

* Cladosiphon mauritianus Børgesen, 1941: 54–57 , figure 22 , pl. II

( figures 25, 26 )

Reference: Børgesen, 1941: 54–57, figure 22 , pl. II (~ C. mauritianum ).

Type locality. Cannoniers Point , Mauritius .

Vouchers. HEC 14789 (zF), 25 September 2001, Passe Grand Bassin (s.s. 4) .

Ecology. Epilithic close to spring low water mark, in a pool. Only a single, large specimen observed.

Distribution. Mauritius ( Børgesen, 1941: 54–57, figure 22 , pl. II), Rodrigues

(this paper).

Unchecked data from literature

Eudesme J. Agardh

Eudesme virescens (Carmichael ex Berkeley) J. Agardh, 1882: 31

Mentioned by Dickie (1877a, as Mesogloia virescens Carmichael ex Berkeley ) but not among our recent collection.

This species has been described from different localities around Great Britain. The single observation of this species in the Indian Ocean is that of Dickie (1877a) on Rodrigues. It might represent a misidentification of Cladosiphon mauritianus , which is superficially very similar.

SCYTOSIPHONALES

CHNOOSPORACEAE

Chnoospora J. Agardh

Chnoospora implexa J. Agardh, 1848: 172

( figures 27, 28 )

References: Jaasund, 1976: 49, figure 99; Tseng, 1984: 184, pl. 93, figure 1 ; Cribb, 1996: 39, figure p. 38; Payri et al., 2000: 142, figure p. 143.

Type locality. Near Tor , Sinai Peninsula, Egypt. Vouchers. HEC 14611 and HEC 14613, 18 September 2001, western side of

Cotton Bay (s.s. 13); HEC 14674 (zF), 20 September 2001, Rivière Banane

(s.s. 12); HEC 14719, 20 September 2001, Totor (s.s. 9) .

Ecology. Abundant in intertidal pools, but also observed at about spring low water mark.

Distribution. Bangladesh, India, Indonesia, Kenya, Mauritius ( Børgesen, 1941: 63–65; 1948: 50; 1953: 18), Réunion ( Jadin, 1935: 158), Rodrigues ( Dickie, 1877a: 6), Seychelles, Tanzania.

Note. At some sites (Cotton Bay and Rivière Banane), different growth stages are present: young, hemispherical, densely intricated, rubbery-stiff tufts of 10 cm diameter, branches with short interdichotomies (2–4 mm, figure 27 ), through intermediates, to old, laxly branched, suppler plants, up to 25 cm long, branches with interdichotomies up to 3 cm long ( figure 28 ).

Figures

FIGS 19–24. Chlorophyta. (19) Caulerpa nummularia, proliferating from primary, peltate assimilator (HEC 14609 p.p.). (20) Rhipidosiphon javensis (HEC 14763). (21) Udotea sp. (HEC 14759). (22–24) Udotea palmetta (HEC 14817): (22) general morphology of large, fertile specimen; (23) gametangia growing from the blade surface; (24) gametangia growing from the blade margin. Scale bars: 2 mm (19, 20); 1 cm (21, 22); 1 mm (23); 500 mm (24).

FIGS 25–30. Phaeophyta. (25, 26) Cladosiphon mauritianus (HEC 14789b): (25) general morphology; (26) apical branches. (27, 28) Chnoospora implexa (HEC 14674b): (27) compact form; (28) thin, slender form. (29) Hydroclathrus tenuis (HEC 14756d). (30) Asteronema breviarticulatum, rope-like appearance of intertwined filaments (HEC 14884). Scale bars: 2 cm (25); 1 cm (26–30).

FIG. 1. Sampling stations. See table 1 for a list of the stations and their GPS coordinates. Map redrawn from Wells (1988). The outer grey line represents the fringing reef.