MARINE MACROALGAL DIVERSITY OF THE REPUBLIC OF PANAMÁ

(poster presentation at the Annual Meeting of the Phycological Society of America, San Diego, CA, 15-19 July 2000)

Wysor, B. (1), W. H. C. F. Kooistra (2), S. Fredericq (1).

(1) University of Louisiana at Lafayette, Department of Biology, PO Box 42451, Lafayette, LA 70504-2451, USA.

(2) Mariene Biologie, Biologisch Centrum, Postbus 14, 9750 AA Haven (GN), The Netherlands.

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Abstract

 

The marine flora of Panamá remains poorly described to date, having been described from a few sporadic and species poor (<50 species) collections in the early half of the century and a couple of dedicated surveys in the latter half. With the exception of a few studies which have focused on particular genera or species, only a single marine floral survey has been published in the past three decades. In 1999 we collected marine algae from 78 different collection sites along both coasts of Panamá over a 10 month period of time. Over 1500 specimens have been curated, representing 250 Caribbean species and 117 Pacific species. This is an increase in algal diversity of approximately 100 and 50% for the Caribbean and Pacific flora, respectively, relative to Earle's compilation of 1972. We estimate that algal diversity in Panamá may approach 450 species as the remainder of the collection is identified and previous records are incorporated.
 

Introduction

 

As part of a project which seeks to investigate the role the Panamá Canal has played (if any) in the current distribution of marine macroalgae along the coasts of Central America we assessed marine floristic diversity along the Caribbean and Pacific coasts of Panamá. With the exception of a few studies which have focused on particular genera or species (Hay and Gaines, 1984; Hay and Norris, 1984; Kilar and Norris, 1988), only a single marine floral survey has been published in the past three decades (Earle, 1972). Prior to our study, 119 taxa were known from the Caribbean coast and 80 taxa were known from the Pacific coast. In our collections of 1999 we uncovered a tremendous diversity of macroalgae heretofore unreported in the literature.
 

Study Area and Methods

 

Panamá hosts two varied mainland coastlines totaling some 1800 kilometers in addition to an extensive island shoreline (Fig 1.). The Pacific shores, with a tidal amplitude of up to 6 m, consist of rocky outcrops with numerous tide pools and a diverse low-tidal algal turfs. Extensive sand and mud flats and mangrove forests crowd the more protected shorelines. Corals are present but rarely develop into elaborate reefs. In contrast, the Caribbean coastline experiences minimal tidal flux (<0.5 m) and is characterized by subtidal limestone platforms, sand and mud plains, diverse reefs, seagrass meadows and mangroves.

 

Fig. 1.

 

We collected samples from 78 different collection sites covering diverse habitats along both coasts of Panamá. Sampling over a 10 month period provided some seasonal resolution within our sampling schedule, however, most sites were sampled only once. Collections were made primarily by wading, snorkeling, SCUBA diving and incidental dredging. Material was transported to the lab in chilled seawater and maintained in flow-through seawater aquaria prior to identification and preservation. When sufficient material was available specimens were preserved in triplicate: 1) 5-10% formalin-seawater for morphological studies, 2) multiple herbarium sheets as vouchers and 3) silica gel desiccant or 95% ethanol for molecular genetic studies.
 

Results

 

Our collecting efforts have thus far, resulted in an increase of estimated total algal diversity of over 125% for the Republic of Panamá . To date, 452 taxa have been recorded for both coasts of the Republic of Panamá (Table 1) including previous reports from the literature. The Caribbean flora is considerably more diverse than that of the Pacific (species lists available upon request; contact wysor@louisiana.edu).
 

Table 1. Summary of floristic records for the Republic of Panamá (Union, indicates the number of taxa common to both coasts). Taxa in this collection that have not been identified to species but are identified to genus are regarded as new records if the genus has not been previously recorded for Panamá . For cases in which Earle (1972) lists "Genus sp." and the genus is represented by a designated species in the present collection, the taxa is regarded as a new record. Where we have recorded "Genus sp." and Earle has designated a particular species of that genus, the as yet undetermined specimen is not regarded as a new record unless it is definitely different from other species designated in this collection or from Earle's compilation. Finally, "Genus sp." is counted only once to accommodate all undesignated species within a genus except in certain cases where sorting on the grounds of obvious morphological differences leads us to believe that different species have been collected.

     New Species (var.) Records  Total Estimated Species (var.)
 Caribbean Rhodophyceae 96(1) 165(1)
  Chlorophyceae 54(9) 88(15)
   Phaeophyceae 17(1) 38(1)

Total

   167 (11) 291(17)
Pacific Rhodophyceae 52 109(4)
  Chlorophyceae 22 42(2)
   Phaeophyceae 13 23

Total

   87 174(6)

 Union

     34(2)
       
 Total Estimated Algal Diversity for the Republic of Panamá  431(21)
 
Of 308 Caribbean taxa, 178 appear to be new records and 87 of 180 Pacific taxa are new for the country. Determinations of the 1500 specimens collected from both coasts of Panamá are incomplete (Table 2).
 
 

Table 2. Taxonomic resolution of the collection.

   # specimens  UnID to Genus  UnID to species

 Caribbean

 562 70 (12.5%) 326 (58%)
  276 0 26 (9.5%)
  108 0 16(125%)

Total

 946 70 (7.5%) 368 (39%)

Pacific

 348 114 (32.8%) 253 (72.7%)
  119 0 39 (32.8%)
  86 0 40 (46.5%)

Total

 553 114 (21%) 332 (60%)
 
 
Many of these specimens do not fit current taxonomic descriptions and may represent new species. One new species (Fig 2.) has aleady been described (Lin et al. in preparation). Considering that 40 and 60% of the Caribbean and Pacific collections, respectively, remain to be identified to species we are confident that the data presented here represent a conservative estimate of marine macroalgal diversity. Figures 2-11 represent a small sample of additional noteworthy records from the Caribbean Coast.
 
Fig. 2. Nitophyllum wysorii.
 
Fig. 3. Cryptonemia sp. This specimen resembles Cryptonemia crenulata (Fig. 4) in gross morphology and some cellular characteristics, however, in size it is much reduced.
 
Fig. 4. Cryptonemia crenulata..
 
Fig. 5. Cryptonemia sp.
 
Fig. 6. Rhipidosiphon floridensis. This may represent the largest known specimen of this alga. Despite it's much larger size than described specimens in the literature, siphon measurements and structural composition are consistent with published ranges. Characteristic of the genus is a monosiphonous stipe, shown in the lower right corner. Rhizoidal outgrowths which hold the alga in the sand from which it was collected are shown in the upper right corner.
 
Fig. 7. Agardhinula sp. Flagellar outgrowths along the margins strongly attach this procumbent red alga to hard substrate. While cellular features ally this alga with the genus Agardhinula, the procumbent growth form and the flagellar outgrowths are at odds with the description ofAgardhinula brownea.
 
Fig. 8. Gracilariopsis sp. DNA sequence data suggests that this specimen may represent an as yetundescribed species (Fred Gurgel, personal communication).
 
Fig. 9. Sebdenia sp.
 
Fig. 10. Meristotheca sp.
 
Fig. 11. Predaea sp.
 

Discussion

 

The few reports on the seaweeds of Panamá depict an impoverished flora. Yet, our data reveal macroalgal diversity comparable to many other countries in the Caribbean and eastern Pacific which have received more intensive attention in terms of marine ecological research and biodiversity surveys (Table 3 and 4). Even our current estimate of diversity is assuredly an underestimate of the actual species diversity considering that we neither assessed seasonal variation in macroalgal assemblages nor epiphyte diversity. A survey of the literature reveals that macroalgal diversity in Panamá is actually higher than in most other countries of either the Caribbean or the eastern Pacific (Tables 3 and 4).
 
Table 3. Macroalgal species diversity for various Caribbean countries.
 # sp.  Country  Source
 27  Guatamala  Bird and McIntosh, 1979
 45  San Andres  Kapraun, 1972
 97  Nicaragua  Phillips et al., 1982
 108  Honduras  Ogden, 1998
 133  Trinidad  Richardson, 1975
 147  Cuba  Kusel, 1972; Sosa, 1977
 160  Venezuela  De Rios, 1972
 165  Colombia  
 180  Antigua  Price and John, 1979
 181  Belize  Littler and Littler, 1997
 239  Dominican Republic  Diaz-Piferrer, 1978
 263  Costa Rica  Soto and Ballantine, 1986
 263  Aruba/Bonaire  Vroman and Stegenga, 1988
 281  Cozumel, MX  Mateo-Cid and Mendoza-González, 1991
291
Panamá
this study
 473  Puerto Rico  Ballantine and Aponte, 1997
 
Table 4. Macroalgal species diversity for various eastern Pacific countries.
 # sp.  Country  Source
10
Guatamala
Bird and McIntosh, 1979
25
Nicaragua
Dawson, 1962a
93
El Salvador
Dawson, 1961
125
Colombia
Schnetter and Bula Meyer, 1982
154
Peru
Dawson, 1964
174
Panamá
this study
235
Central America
Dawson, 1962b
 
We attribute the tremendous number of new records and overall diversity in Panamá to sampling frequently over an extended period of time as well as sampling a diversity of habitats from the supra-littoral spray zone to the subtidal. Because sampling of the macroalgal flora in Central America is so limited, however, it is difficult to determine whether the apparently high diversity of the Panamanian flora is real or merely perceived as such. Nevertheless, once the Panamá collection is completely resolved taxonomically we intend to compare diversity throughout the tropical Atlantic and eastern Pacific in order to identify biogeographical relationships.
 
The isthmus of Panamá provides an ideal framework in which to address biogeographical and evolutionary questions. The emergence of the isthmus is not only well known geologically, but of sufficiently recent occurrence that rates of divergence can be reliably estimated among closely related species or even within species. From this collection, 36 taxa are recorded from both the Pacific and Caribbean coasts. Many of these taxa are currently being investigated to determine how closely related amphi-isthmian species pairs are and if there is any gene flow across the isthmus. Trans-isthmian genetic exchange is very interesting especially in light of the Panamá Canal which may serve as a corridor for the transfer of native and exotic species which may be associated with shipping traffic.
 

Future work

 

Determinations will continue to be made until the collection is completely resolved taxonomically. DNA sequencing will be used in addition to traditional morphological characters to aid in the identification of problematic taxa which do not seem to conform to current species descriptions. Amphi-isthmian species pairs will continue to be sequenced to determine whether populations separated by the isthmus of Panamá have been separated historically (since the emergence of the isthmus ~3.5 million years ago) or whether populations represent recently introduced stock.
 

Acknowledgements

 

We gratefully acknowledge Dr. Peter Glynn, Kirk Zigler, and Haris Lessios for providng logistic help with collections, Prof. Dr. C. van den Hoek and Dr. O. de Clerck for help with identifications. This work was supported financially by a United States Information Agency Fulbright Fellowship and a University of Louisiana at Lafayette Board of Regents doctoral fellowship awarded to BW. Additional support was provided by the Smithsonian Tropical Research Insitute which provided access to laboratory facilities and equipment.
 

Literature cited

 

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