Hydroclathrus tenuis Tseng and Lu, 1983: 185

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 : 3007

* Hydroclathrus tenuis Tseng and Lu, 1983: 185 , figure 1 ; pl. 1, figure 1a

( figure 29 ) References: Tseng, 1984: 186, pl. 94, figure 3 ; Verheij and Prud’homme van Reine,

1993: 435, pl. 13, figure 1 ; Trono, 1997: 123, figure 83; Coppejans et al., 2000: 60,

figure 22 .

Type locality. Xisha Island , Guangdong Province, China .

Voucher. HEC 14756d, 22 September 2001, Grand Baie (s.s. 11) .

Ecology. Intertidal, about spring low tide level, wrapped around coral boulders. Also found drifting in the lagoon in huge quantities, locally forming a floating mass of 0.5 m thick.

Distribution. China, Indonesia, Rodrigues (this paper), Tanzania.

Notes. (1) See note for H. clathratus . (2) According to Tseng (1984: 186) this species is endemic to China. Since then it has been reported from one site in Indonesia ( Verheij and Prud’homme van Reine, 1993: 435), from the Philippines ( Trono, 1997: 123) and from several locations in Tanzania ( Coppejans et al., 2000: 60). (3) When decaying, H. tenuis turns green. As a result it has been identified as Ulva reticulata in previous ecological studies of Rodrigues, based on the morphological resemblance.

Figures

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.

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).

FIGS 2–6. Chlorophyta. (2) Microdictyon tenuius, detail of branching and anastomosing patterns (HEC 14849). (3) Bryopsis pennata var. pennata, branchlets of last order contiguous and in a single plane (HEC 14796 p.p.). (4) Bryopsis pennata var. leprieurii, branchlets of last order interrupted and in a single plane (HEC 14757).(5) Bryopsis pennata var. secunda, branchlets of last order curved in one direction (HEC 14796 p.p.). (6) Chamaedoris delphinii (HEC 14617). Scale bars: 250 mm (2); 5 mm (3–5); 1 cm (6).

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).