The Occurrence of Jolyna laminarioides (Phaeophyta) in the Arabian Sea and the Indian Ocean and a New Report of Melanothamnus somalensis (Rhodophyta)

Some collections made in the People's Democratic Republic of Yemen have revealed the occurrence of two taxa of benthic marine algae of special significance. Jolyna laminarioides (Scytosiphonaceae, Phaeophyta), a taxon recently described from Brazil, represents an interesting disjunct distribution pattern. Earlier reports of Endarachne binghamiae from Pakistan and Oman and Petalonia fascia from PDR Yemen were based on misidentifications and also belong to Jolyna laminarioides. Melanothamnus somalensis (Rhodomelaceae, Rhodophyta), a poorly known monbtypic genus, has also been identified from PDR Yemen. It has already been identified as IPterosiphonia cloiophylla based on a collection from southern Oman. Material and Methods Both specimens preserved in 5% formalin in sea-water and dried herbarium specimens were used in this study. Collection data for the PDR Yemeni, Pakistani, and Omani specimens that were used in this study are provided in the Collections Cited sections under each species. Specimens are deposited in the University of Michigan Herbarium (MICH), in the personal Herbarium of S. A. Banaimoon (HB), or in the Tropical Marine Research Unit, Biology Dept., University of York, England (Y). The following collection of Jolyna was used for comparison: leg. J. P. Gilberto Mitchell (in MICH), 18. viii. 1978, Ponta das Focas, Lagoinha, Rio de Janeiro State, Brazil. Figure 6 is from a Brazilian specimen (Praia de Geriba, Rio de Janeiro State: leg. M. R. A. Braga (in SP), 19. xi. 1978. Also, the following collection of Endarachne binghamiae J. Agardh was examined: leg. M. Wynne 7354 (in MICH), 23. iv. 1983, Bats Cave, north of East London, Cape Prov. , South Africa. J Present address: P.O. Box 3008, 13031 Safat, Kuwait Jolyna laminarioides Guimaräes in Guimaräes et al. With the recent description of the monötypic genus Jolyna from Brazil (Guimaräes et al. 1986), the Scytosiphonaceae (Phaeophyta) now contains eight genera (and possibly a ninth genus, the poorly known Utriculidiuni). These genera share the cytological characteristic of each cell containing a single large platelike chloroplast with a conspicuous projecting pyrenoid and the reproductive characteristic of having only plurilocular sporangia produced by the macrothallus (Wynne 1982). three of these genera, Petalonia, Endarachne, and Jolyna, have a similar morphological form, namely, simple foliose or strapshaped blades. Differences in the internal anatomy are used to distinguish them. The medulla of Petalonia is comprised of rounded cells (Fletcher 1987). In contrast, the medulla in the other two genera is comprised of narrow filaments. In Endarachne the medulla is comprised of densely intertwined, branched filaments [J. Agardh 1896, Okamura 1901, as Phyllitis fascia (O. F. Müll.) Kütz. ; Setchell and Gardner 1925]. In Jolyna the medulla is comprised of fiber-like cells in a complex ground tissue composed of a dense network of interconnected filaments (Guimaräes et al. 1986). Botanica Marina / Vol. 33 / 1990 / Fasc. 2 Copyright © 1990 Walter de Gruyter · Berlin · New York 214 Wynne and Banaimoon: Occurrence ofJolyna laminarioides and a new report of Melanothanmus somalensis