Raúl Aguilar-Rosas

First record of Undaria pinnatifida (Harvey) Suringar (Laminariales, Phaeophyta) on the Pacific coast of Mexico

Abstract Undaria pinnatifida, a laminarian kelp (Phaeophyta) native to Japan, Korea and northern China, has been introduced recently to the coast of southern California (USA). We present the first record of this invasive species on the Mexican Pacific coast, and show the current southern limit along the Pacific coast of North America. U. pinnatifida was found on September 28th, 2003, growing attached to small rocks on a sandy bottom in the subtidal zone at 12–14 m depth at Todos Santos Islands, in Baja California, Mexico. This population consisted of 15 sporophytes, with an average length of 50 cm and with mature sporophylls. This new finding suggests that the colonization of the Pacific coast of North America by this invasive species is still occurring, and its distributional range is expanding.

Ecological aspects of Sargassum muticum (Fucales, Phaeophyta) in Baja California, Mexico: reproductive phenology and epiphytes

The reproductive phenology and epiphytic macroalgae of Sargassum muticum were studied through an annual cycle (September 1987 to November 1988) at two sites on the northwestern coast of Baja California, Mexico, which were subjected to different degrees of wave exposure. Sargassum muticum is a brown alga of Japanese origin, now considered a permanent member of the marine flora of Baja California. A similar reproductive development was observed at both sites, with a maximum percentage of reproductive plants from May to July (spring-summer) and minimum from December to March (winter). Reproductive plants were found throughout the year. A total of 48 species of epiphytes were identified and seasonal variation in their diversity was observed. The greatest diversity was found at the more protected site.

Marine Algae from the Northeast Coast of Baja California, México

Abstract Seasonal samplings were conducted at six sites on the northeastern coast of Baja California, Mexico, (between Campo Hawaii and Puertecitos), in the northern zone of the Gulf of California. A total of 140 taxa of marine algae were determined, of which 125 are cited for the first time for the area of study. The families with best representation are: Rhodomelaceae with 20 species, Corallinaceae with 16, Ceramiaceae with 11, Gracilariaceae with 9 and Dictyotaceae with 9. A higher diversity was found at the beginning of autumn, winter, at the end of spring, and a lower one in summer. Lower diversity was found at the sites located towards the north: Campo Hawaii with 12 species, El Machorro with 21 and El Faro de San Felipe with 44. These are places in which the beaches are broad and composed of sand and with few pebbles. A higher diversity was found at the sites located towards the south: El Coloradito with 75 species, Playa Santa Teresa with 76 and Puertecitos with 85. These localities are characterized by stable rocky substrates, with numerous intertidal pools. The most common species with regard to distribution and occurrence over time are: Cladophora prolifera, Struveopsis robusta, Dictyota flabellata, Gelidium pusillum, Gracilaria subsecundata, Prionitis abbreviata, Corallina vancouveriensis, Lithophyllum imitans, Spongites decipiens and Spyridia filamentosa. Twenty-one species are reported for the first time from the northern Gulf of California, and another three species represent new records for the Gulf: Gelidiocolax microsphaerica, Gastroclonium parvum, and Leathesia nana.

Infrared analysis of eleven carrageenophytes from Baja California, Mexico

Infrared analyses of the carrageenan in ten species (representing four genera) of Gigartinaceae and one species of Hypneaceae in different reproductive phases from the northwestern coast of Baja California were studied. Cystocarpic samples of the Gigartinaceae presented varying degrees of a к/ι ‘hybrid’. The degree of hybridization was determined based on the ratio between the peak absorbances at 805/845 cm−1. A high correlation was observed between the 805/845 cm−1 and 805/970 cm−1 ratios. Tetrasporic samples of Gigartina leptorhynchos, Iridaea splendens, Rhodoglossum affine and R. roseum, presented a λ-carrageenan profile, whereas Gigartina tepida, G. exasperata, G. harveyana, G. canaliculata and G. spinosa presented a e-carrageenan. The tetrasporic sample of Hypnea valentiae showed a κ-carrageenan with a very low degree of hybridization.

New Record of Sargassum filicinum Harvey (Fucales, Phaeophyceae) in the Pacific Coast of Mexico

Sargassum filicinum Harvey, a brown alga (Phaeophyceae) native to Northeastern Asia, has been recently reported from the coast of Southern California (USA). Here we report the occurrence and range extension of this introduced species, as we found the alga at La Jolla and Rancho Packard in Todos Santos Bay, Baja California, Mexico. The first collections of S. filicinum correspond to several immature plants, found on September 8, 2005, drifting in the intertidal zone at La Jolla. Later on November 9, 2006, we found a well-established population in Rancho Packard in the middle intertidal zone to 2 m depth. Since S. filicinum is an annual monoecious species with air bladders, the risk there is a high risk of spreading rapidly along the Pacific, as in the case for S. muticum. The population in Rancho Packard extends 500 m along the coast, consisting mainly of young plants with an average length of 30 cm and a density of 5 thallus/m2. This is the first record of this invasive species for the Mexican Pacific coast, and it represents the southern limit along the Pacific coast of North America. This finding suggests that this invasive species has successfully colonized the Pacific coast of North America and its distributional range is still expanding.

Ulva fasciata Delile (Ulvaceae, Chlorophycota): a species newly introduced into Pacific Mexico

Abstract Ulva fasciata Delile is reported for the first time as an introduced species along the coast of the Baja California Peninsula. In 2002–2003, populations of U. fasciata were observed at only three sites (Monalisa Beach, El Faro Beach and mouth of Punta Banda Estuary) on the eastern side of Todos Santos Bay, Baja California, Mexico. The variation in mean thallus size suggests that this species attains maximum development during late summer and early autumn (September), gradually decreases during autumn–winter and disappears during spring (April). Reproductive plants were observed, especially in the warm months (summer–autumn), when seawater temperatures can reach 24°C. A detailed review of specimens housed in Mexican herbaria revealed that U. fasciata is widely distributed along the Mexican Pacific coast, growing on rocks in the midtidal and upper intertidal zones. A detailed description of the vegetative and reproductive structures is provided.

Marine algae from the Gulf of Santa Clara, Sonora, México

Four sites in the Gulf of Santa Clara, northwestern coast of Sonora, Mexico, were sampled seasonally during 1995–1996. A total of 43 species of marine algae were determined, which are recorded for the first time for the area of study. The families with best representation are: Gracilariaceae and Cladophoraceae, each with 5 species; and Corallinaceae, Rhodomelaceae, and Ulvaceae, each with 3. The highest diversity was found in autumn, the lowest in summer. The sites with the low diversity were Piedras del Burro with 7 species and El Tornillal with 18. These places are broad beaches, composed of sand and with few pebbles. The higher diversity was found at Punta Gorda with 34 species and Piedras de La Salina with 26. These localities are characterized by relatively stable rocky substrates, with some intertidal pools. The most common species regardless to distribution and occurrence over time were: Spyridia filamentosa, Dictyota flabellata, Struveopsis robusta, Cladophora microcladioides and Enteromorpha linza. Rosenvingea antillarum and Cladophora vagabunda represent new records for the Gulf of California. Nine epiphytic species were identified, which were frequently observed on Gelidium crinale, Spyridia filamentosa and Dictyota flabellata.

New Records of Marine Rhodophyta from the Pacific Coast of Mexico

Two species of marine red algae, Jania ungulata (Yendo) Yendo f. brevior (Yendo) Yendo and Peyssonnelia japonica (Segawa) Yoneshigue (Rhodophyta) were collected for the first time from Mexican Pacific coast. Their vegetative and reproductive structures are described, as well as the habitat where they were found and their geographical distribution along the Pacific coasts of Mexico. Jania ungulata f. brevior is a commonly growing epiphytic and Peyssonnelia japonica is epiphyte. The fact that we found this new records in Mexican coast is noteworthy, due that this species are originally described in Japanese coast. The absence of records of this species in the Mexican coast is likely related in part to the lack of specific collections and the fact that the specimens are small and delicate, and may commonly be unnoticed during samplings.⤚ꄀ᐀㘳㈻㘳㈮〹㔱㤻㘳㈮㔻଀䅧物捵汴畲攀

Geographic correlation of morphological and molecular variation in Silvetia compressa (Fucaceae, Fucales, Phaeophyceae)

Abstract Silvetia compressa is a common member of the upper intertidal fucoid community on the Pacific coast of North America from Humboldt County, California, to Punta Baja, Baja California, Mexico, including coastal islands. On the mainland, there is considerable morphological variability involving robustness, branching pattern, and size and shape of receptacles. A latitudinal cline is not evident. By contrast, there is relatively little morphological variability among populations in the Channel Islands of southern California and coastal islands of northern Baja California, These insular populations are perceptibly distinct from all mainland populations except for several in northern Baja California. After comparing populations from various parts of the range of the species, including all coastal islands, we conclude that two subspecies may be recognized. In subsp, compressa, which occurs only on the mainland, the frond is robust and straggly, with dichotomous branching that tends to be irregular, and with linear receptacles often tapered to a point. In the newly described subsp. deliquescens, which is chiefly insular but also occurs on the coast of northern Baja California, the fronds form hemispherical clumps, with densely and regularly branched slender axes and short, blunt, ellipsoidal receptacles. A few populations on the Monterey Peninsula in which the fronds are unusually delicate were described by Setchell and Gardner as f. gracilis, to which was assigned a population from Santa Catalina Island. We conclude that the Monterey Peninsula populations of f. gracilis constitute an ecotype of subsp, compressa, whereas the Santa Catalina Island popUlation is referable to subsp. deliquescens. Comparison of nucleotide sequences from the ITS regions of rDNA revealed no molecular differentiation in populations of subsp. compressa from Baja California and central California, including those assignable to f. gracilis. The sequence in the three populations of subsp, deliquescens was identical, but differed by 2 bp (0.3%) from that of subsp, compressa.