Francisco F. Pedroche

MARINE RED ALGAE OF THE MANGROVES IN SOUTHERN PACIFIC MEXICO AND PACIFIC GUATEMALA

Collections of red algae were made from the mangroves in southern Pacific Mexico and Pacific Guatemala in 1993. New records for these areas include Caloglossa ogasawaraensis, C. stipitata, C. leprieurii, Bostrychia moritziana, B. pinnata, B. radicans and Catenella caespitosa. In Caloglossa stipitata as defined by King and Puttock (1994) secondary blades arise from the pericentral cell in the same plane as the main blade; in the Guatemala population however, secondary blades develop from the axial cell as in C. leprieurii. The morphological characters delimiting B. moritziana are also discussed. Culture observations and polyol data suggest important new areas of research on marine red algae from mangrove ecosystems.

Marine red algae of the mangroves in Pacific México and their polyol content

Caloglossa sp. 1, Bostrychia moritziana and Bostrychia radicans were collected from the mangroves of Barra de Navidad (Jalisco), San Blas (Nayarit) and Teacapan (Sinaloa). Caloglossa sp. 1 was previously known only from Baja California Sur. Bostrychia calliptera was obtained from Estero San Juan, San Blas (Nayarit). The concentrations of D-mannitol, the main osmolyte of the genus Caloglossa, ranged in C. sp. 1 from 360 to 395 μmol/g DW when grown in 25-35‰ seawater. In Bostrychia the polyol contents correlated with the salinity regime of the habitat

Molecular evidence for Chondrophycus poiteaui var. gemmiferus comb. et stat. nov. (Ceramiales, Rhodophyta) from the Mexican Caribbean Sea: implications for the taxonomy of the Laurencia complex

Abstract Molecular studies were carried out on Chondrophycus gemmiferus and C. poiteaui (Rhodomelaceae) from the Mexican Caribbean Sea. These species are morphologically related, but differ mainly in the presence of the apiculate projection of epidermal cells near the apices of branches. Both species belong to Chondrophycus, as indicated by the presence of two periaxial cells per axial segment and a 90° arrangement of tetrasporangia, but share characteristics with Laurencia species (e.g., presence of secondary pit connections between adjacent epidermal cells). The phylogenetic position of these species was inferred by an analysis of chloroplast-encoded rbcL gene sequences of 21 taxa, using two members of the Rhodomelaceae and two of the Ceramiaceae as outgroups. The results corroborate the taxonomy of the Laurencia complex, which comprises the genera Laurencia, Chondrophycus and Osmundea, and indicate that rbcL provides an adequate phylogenetic signal to study the intergeneric and interspecific relationships within the complex. In spite of this, relationships within the clade formed by C. gemmiferus and C. poiteaui were not resolved by any analysis because of the low level of genetic variation between their rbcL sequences (0.01–0.02%). On the basis of both molecular data and morphological similarities, we concluded that C. gemmiferus should be considered as a variety of C. poiteaui and the following new combination is proposed: Chondrophycus poiteaui var. gemmiferus (Harvey) comb. et stat. nov.

Molecular phylogeography of Pteronotus davyi (Chiroptera: Mormoopidae) in Mexico

Abstract Pteronotus davyi, Davys naked-backed bat, is a tropical bat whose current distribution in Mexico covers the watersheds of the Pacific and the Gulf coasts of Mexico, converges at the Isthmus of Tehuantepec, and continues into the Yucatan peninsula. We evaluated phylogeographic relationships among 18 populations in Mexico using data from the nucleotide sequence of the hypervariable II domain of the mitochondrial DNA control region from 105 specimens. Extant populations were distributed over 3 geographic regions (Pacific Coast, Gulf Coast, and Southeastern) that were delineated a priori according to floristic characteristics and biogeography. Coalescent simulations supported a phylogeographic model of 2 refugia situated in the south of Mexico (Arc and Soconusco refuges) during the late Pleistocene, followed by expansion into Pacific Coast, Gulf Coast, and Southeastern groups. The populations of the Southeast were genetically divergent from the Pacific and Gulf Coast populations, supporting the existence of 2 distinct lineages of P. davyi in Mexico, likely due to the Isthmus of Tehuantepec acting as a geographical barrier. Examination of our data revealed genetic differentiation of the Pacific and Gulf coastal groups but at a lower level relative to the Southeast. This pattern suggests that the Sierra Madre Occidental, Sierra Madre Oriental, and Sierra Madre del Sur act as physical barriers to dispersal for P. davyi.

Contribution of external morphology in solving a species complex: The case of Prorocentrum micans, Prorocentrum gracile and Prorocentrum sigmoides (Dinoflagellata) from the Mexican Pacific Coast

Prorocentrum micans Ehrenberg, Prorocentrum gracile Schütt and Prorocentrum sigmoides Böhm are planktonic dinoflagellates present along the Mexican Pacific coast. These three species can be treated as a species complex because of similar shape and size. The taxonomy of the group has been based on cell form and size, the presence or absence of apical spines and the ornamentation of the main valves. A morphometric study of samples from 11 locations from the Mexican Pacific coast and from laboratory cultures is presented. The presence of a mucron (small tooth) in the antapical region of P. gracile and P. sigmoides morphotypes was recorded for the first time. Morphotypes were defined using as the main criteria the size of pores in relation to the size of the depressions on the cell’s surface, the presence of a mucron in the posterior end of the cell and the shape of the valve margins. Results show a clear distinction between the morphotype P. micans and the P. gracile–P. sigmoides. P. sigmoides is suggested to be a junior synonym of P. gracile as no convincing characters could distinguish these two morphotypes.

Caloglossa apomeiotica sp. nov. (Ceramiales, Rhodophyta) frorn Pacific México

A new species, Caloglossa apomeiotica West et Zuccarello, is described based on material from San Carlos, Bahia Magdalena, Bajo Califomia Sur. The species is morphologically similar to C. leprieurii but characterised by the production of bisporangia and, less commonly, tetrasporangia, and the lack of sexually reproducing plants. In eight culture isolates from throughout the geographic range of the species only the bisporangia were viable. The present known distribution of Caloglossa apomeiotica is from Bahia Magdalena, Baja California Sur to Barra de Navidad, Jalisco in Pacific Mexico. It is suggested that C. apomeiotica is derived from C. leprieurii populations further south in the Americas through a loss of sexual reproduction

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.

New records of red algae from mangroves in El Salvador and Pacific Mexico, combining culture and molecular observations

Abstract The algae of El Salvador have received limited attention. We combined collections from the mangroves of El Salvador and neighboring southern Mexico, and used culture studies and molecular analysis to gain insights into the diversity in this poorly explored region. Bostrychia montagnei, Caloglossa apomeiotica, and Caloglossa ogasawaraensis were newly recorded in El Salvador. Bostrychia montagnei has not been reported from the Pacific Americas before. B. montagnei normally produced axial cells with two-tier cells, typical of the species, but sometimes a series of axial cells had three-tier cells. This was a significant tier cell number variation not previously seen in Bostrychia species. Bostrychia montagnei had a Polysiphonia-type sexual life history with both unisexual and bisexual gametophytes. Caloglossa apomeiotica isolates in culture from El Salvador and Chiapas, Mexico, either had a normal sexual life history or asexual recycling of tetrasporophytes. Those found in El Salvador were the first record of C. apomeiotica south of Jalisco, Mexico, a distance of 1200 km. Four strains isolated from El Salvador and Chiapas, Mexico, which were morphologically part of the Caloglossa leprieurii sensu lato lineage, were analyzed; however, they were not closely related to any named species, indicating that this is a new species that will require further study.

Genetic diversity of the mangrove-associated alga Bostrychia radicans/Bostrychia moritziana (Ceramiales, Rhodophyta) from southern Central America

Previous studies suggested that the biodiversity of the mangrove‐associated Bostrychia radicans/Bostrychia moritziana species complex on the Pacific coast of Central America, based on genetic and reproductive data, were low compared with similar areas on the Atlantic coast. Evolutionary scenarios were proposed based on either a recent introduction to the Pacific, or a more uniform environment leading to genetically connected populations and low differentiation between populations. We sampled more extensively in southern Mexico, Guatemala and El Salvador and sequenced the samples for the RuBisCo spacer. Our results show that genetic diversity is high in these populations. Many haplotypes retrieved are also found in the Atlantic Ocean (USA, Brazil), an observation not made before. Data suggest that populations are highly differentiated with little evidence of isolation‐by‐distance. The population at La Puntilla, El Salvador is highly differentiated from other populations. Data also suggest that diversity is reduced in a northerly direction, with only one haplotype, unique to Pacific Central America, found north of Chiapas, Mexico. This could be due to northern expansion of this unique genotype as sea surface temperatures ameliorated following the last glacial maximum. Our data do not support the previous proposition of low diversity in the east central Pacific and suggest that much of the Pacific Central America diversity is from before the closure of the Isthmus of Panama.

The occurrence of Dictyota canariensis (Dictyotales, Phaeophyceae) in the Gulf of Mexico

Abstract The brown alga Dictyota canariensis (Grunow) Tronholm has so far been reported only from the eastern Atlantic Ocean (Canary Islands, Cape Verde, Madeira). In the present work, we record the species for the first time from the shores of the Gulf of Mexico, occurring in Montepío, Veracruz. The specimens were collected in December 2011 and October 2013, growing in the intertidal zone on moderately exposed rocky shores. To confirm the identification, we conducted phylogenetic analyses, combining the partial sequences of psbA and cox1 genes of l7 taxa. The low uncorrected “p” distance values obtained between Mexican and Canary Island specimens for each gene (0.3% for psbA and 1.8% for cox1) are indicative that these specimens most likely belong to the same species. The low genetic divergence is corroborated by morphological observations, which show that the Mexican specimens share the presence of rectangular pigmented patches near the rounded to obtuse apices, margins with triangle-shaped teeth, and a monostromatic medulla with D. canariensis. Additionally, male reproductive structures are described for the first time for this species.