NEW RECORDS OF BENTHIC MARINE ALGAE ...

BULLETIN OF MARINE SCIENCE, 66(1): 119–130, 2000

NEW RECORDS OF BENTHIC MARINE ALGAE FROM ISLA COZUMEL, MEXICO: PHAEOPHYTA AND CHLOROPHYTA A. Catalina Mendoza-González, Luz Elena Mateo-Cid and Richard B. Searles ABSTRACT Waters off the island of Cozumel on the east coast of the Yucatán peninsula in Mexico were investigated using SCUBA. Species recorded here supplement earlier reports of seaweeds collected in shallow water from this Caribbean island. Twenty-three taxa of Phaeophyta and 72 Chlorophyta were collected. We record for the first time on Cozumel ten species of Phaeophyta and 24 species, three varieties and four forms of Chlorophyta. Four of the brown algal records and 16 of the green algal records are new records for Mexico. Collections of Onslowia bahamaensis are the first outside of the Bahamas where it was originally described in 1978. The reports of Entocladia ventriculosa, Penicillus dumestosus f. expansus, and P. pyriformis f. explanatus are the first since Børgesen’s original description of them from the Virgin Islands early in the century. We also report Trichosolen blomquistii for the first time outside of Puerto Rico. The reports of Rhipiliopsis profunda from 27–30 m are by far the shallowest depths in which this deep-water alga has been collected and are the only records of this species outside of the Bahamas, where it was originally described, and Puerto Rico.

The seaweed flora around the island of Cozumel has previously been investigated by Huerta (1958, 1961), Taylor (1972), Garza (1975), Huerta and Garza (1980), Huerta et al. (1987), and most recently by Mateo-Cid and Mendoza-González (1991). These earlier studies identified 315 taxa of algae, exclusive of diatoms (Mateo-Cid and MendozaGonzález, 1991), including 36 taxa of Phaeophyta and 89 Chlorophyta. All of these earlier studies were restricted to collections made in the intertidal and near shore, subtidal depths. The present report is based on deeper water species that have been collected using SCUBA. STUDY AREA The island of Cozumel (48 km long and 16 km wide) lies off the eastern coast of the Yucatán peninsula. The island is separated from the mainland by a channel 19 km wide and over 400 m deep. The water temperatures around the island range from 25 to 28°C (Lewbel and Martin, 1991). Collecting was restricted to the southwest quadrant of the island where there is protection from the prevailing northeast winds. Along this part of the island there is a narrow shelf mostly 1 km or less in width. This shelf begins with intertidal sand or limestone rock beaches and slopes gradually deeper across the shelf, or the shelf starts as rocky, wave-cut ledges that drop from the intertidal to depths of 2–4 m or more before the bottom becomes flat and then gradually slopes toward the shelf edge. Much of the shelf is covered by carbonate sands. Low relief, fossilized carbonate rock reefs emerge through the sand in the shallow (15–20 m deep) parts of the shelf, e.g., Yucab Reef, Tormentos Reef, Chankanab Reef, and Paraiso Reef. These reefs stand 1–3 m above the sandy bottom and appear to be heavily grazed, with little algal growth except for Halimeda spp., encrusting coralline red algae and cryptic algae in cracks and crevices. Richer algal growths are found on flat areas adjacent to these reefs where there may be carbonate rubble or thinly covered rock. Inshore of 119

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BULLETIN OF MARINE SCIENCE, VOL. 66, NO. 1, 2000

Tormentos Reef a meadow of Syringodium filiforme Kütz. hosts many epiphytic algae. Mixed in with the Syringodium are species of Udotea, Penicillus, Caulerpa and other plants that anchor in sand. Plants anchored in sand were also collected from sand flats inshore of Colombia Reef. At the edge of the shelf, usually in depths of 18–30 m, there may be an abrupt drop-off with a near vertical rock wall, e.g., Tunich Reef and parts of San Francisco Reef and Santa Rosa Reef. These walls host luxuriant growths of seaweeds as well as sponges, hydroids, corals and other sessile invertebrates. Other parts of San Francisco Reef are steep, but not nearly as vertical and have low relief rock outcroppings with rich assemblages of algae and animals. Slopes seen at Punta del Sur Reef, Colombia Reef, Palancar Reef, and Santa Rosa Reef are also steep and the emergent carbonate rocks form tall columns and buttresses that rise from depths of 25–30 m to within 8 m of the surface. At the base of the rock columns there are often shallow caves, overhanging ledges, and tunnels. Between rock formations there are steep sandy slopes on which there may be accumulated rubble that, with the rock formations, provide substrata for attached seaweeds. Currents over the shelf in the study area can exceed 5 km h−1 and the strongest currents are usually along the edge of the shelf. The shelf edge habitats generally have much richer growth of seaweeds than the reefs in the mid shelf areas. The waters around Cozumel are part of a national park and off limits for collecting unless special governmental permission is obtained. These waters are otherwise readily available to SCUBA divers. Tourists are the major industry of the island and sport SCUBA-diving is the major attraction for tourists.

MATERIALS AND METHODS Collections were made from 1993 to 1998 on 37 different dives using SCUBA. Because of the high relief of some of the limestone outcrops, collecting on any one dive usually ranged over depths of several meters. The depths listed with each species indicate the minimum depth of the shallowest collection in which the species was collected and the maximum depth of the deepest collection. Collections were preserved in formalin:sea water in the ratio 1:19. Semi-permanent slides were prepared using corn syrup:water 1:1 with a trace of phenol added to prevent fungal growth. Voucher slides and herbarium specimens are deposited at the Escuela Nacional de Ciencias Biologicas (ENCB) at the Instituto Politecnico Nacional in Mexico City, additional vouchers are deposited in the herbarium of Duke University (DUKE).

RESULTS Twenty-four taxa of Phaeophyta were collected, including ten species that were not recorded in earlier reports from Cozumel. Four of these are new records for Mexico. Seventy-two taxa of Chlorophyta were collected, including 24 species, three varieties and four forms that are new records for Cozumel. Thirteen of the Chlorophyta species and three of the forms are new records for Mexico. The additional 10 taxa of Phaeophyta represent a 28% increase in the number of taxa of Phaeophyta in the Cozumel flora; the additional 31 taxa of Chlorophyta increase the number of taxa in that division by 35%. Records of the species collected, the depths over which they were collected, months of collection and a source of an illustration and description of each species are included in Table 1. New records for Mexico or for the island of Cozumel are indicated. Names of species are in accord with Wynne (1998). Authors’ names follow the recommendations of Brummitt and Powell (1992). Herbaria abbreviations follow Holmgren et al. (1990).

MENDOZA-GONZÁLEZ ET AL.: NEW RECORDS OF BENTHIC MARINE ALGAE FROM MEXICO

121

PHAEOPHYTA Ectocarpus elachistaeformis Heydr.—Wynne (1998) retained this species in the genus Ectocarpus Lyngb., whereas Silva et al. (1996) placed the species in Kuetzingiella Kornmann and discuss the possibility that the reports of it from the Atlantic Ocean as E. elachistaeformis may represent reports of a different taxon. Myrionema strangulans Grev.—Records of this small, epiphytic alga in the Caribbean are limited. This is the first record west of Florida and the Virgin Islands. The alga is probably widespread in the Caribbean but overlooked because of its small size. Onslowia bahamensis E. C. Henry.—Most collections were of immature plants without well developed propagules; those propagules that were observed had apical cells deflected distally from the plane perpendicular to the axis of the propagule as described and illustrated by Henry (1987) for this species. It was epiphytic on Dictyota pulchella. Dictyopteris polypodioides (DC. in Lam. & DC.) J. V. Lamour.—Silva in Silva et al. (1996) discusses the tangled nomenclatural and systematic problems associated with plants referred to Dictyopteris polypodioides and D. membranacea (Stackh.) Batters. Lacking resolution of the problems raised by Silva, we follow his practice and refer our plants to D. polypodioides pending further study of these plants. Dictyota hamifera Setch.—This is the second Caribbean record of this tropical Pacific species; it was first reported from the Caribbean by Hörnig et al. (1992) from the coast of Colombia. Dictyota pulchella Hörnig & Schnetter.—Earlier records of this alga from Cozumel were listed as Dictyota divaricata Lamour., a species placed in synonomy by Hörnig and Schnetter (1988) with D. dichotoma (Hudson) Lamour., a European and Mediterranean alga. They erected the new species, D. pulchella, to accommodate the Caribbean algae that had been ascribed to D. divaricata. CHLOROPHYTA Entocladia ventriculosa Børgesen.—This species was originally described by Børgesen (1920) in the walls of Chrysymenia agardhii Harv. from deep-water, 28 m, in what are now the U.S. Virgin Islands. The plants reported here, apparently the first since Børgesen’s original report, were epiphytic on Chrysymenia enteromorpha Harv. and were collected in similar depths. See Wynne (1998) for a discussion of the placement of species in the genus Epicladia vs. Entocladia. Anadyomene saldanhae A. B. Joly & E. C. Oliveira.—As indicated by the numerous collections, this is a common alga in deep-water around Cozumel. It occurs with Rhiphiliopis profunda and Peyssonnelia spp. in low light environments. Microdictyon marinum (Bory) P. C. Silva.—Collected rather regularly in the deep waters of Cozumel. This is the first record of this alga south or west of Cuba. Derbesia vaucheriaeformis (Harv.) J. Agardh.—As in Harvey’s (1858) original description of this species, no fertile material was observed although this alga was encountered regularly in the spring months. The species determination was based on the coarse, greater than 100 μm, diameter of the filaments. Trichosolen blomquistii (Díaz-Pif.) D. M. John.—Díaz-Piferrer (1965) distinguished this species (as Pseudobryopsis blomquistii) from the other, more widely distributed species, Trichosolen duchassaingii (as Pseudobryopsis longipedicellata Blomquist & DíazPif.), on the basis of the larger gametangia, up to 125 μm long vs 83 μm, and shorter

×

×

×

10−27

Dictyopteris justii J. V. Lamour.

× ×

8−27

Dictyota menstrualis (Hoyt) Schnetter, Hö rnig, & Weber-Peukert

×

×

10−24

■ Dictyota hamifera Setch.

×

×

×

8−30 ×

Dictyota cervicornis Kü tzing

×

×

12−21 ×

✷ Dictyota caribaea Hö rnig & Schnetter

×

×

×

×

× ×

×

×

8−27

×

×

12−27 ×

×

×

×

×

Dictyota bartayresiana J. V. Lamour.

×

×

×

×

✷ Dictyopteris polypodioides (DC.) J. V. Lamour.

×

×

12−27 ×

×

✷ Dictyopteris jamaicensis W. R. Taylor

×

10−30

18−24

×

×

21

×

×

✷ Rosenvingea intricata (J. Agardh) Bø rgesen Choristocarpaceae ■ Onslowia bahamensis E. C. Henry Dictyotaceae Dictyopteris delicatula J. V. Lamour.

18−24

8−9

×

21−27

×

Hydroclathrus clathratus (C. Agardh) M. Howe

21−24

18−24

Depth Reefs (m) PN Ch To Y Tu SF SR P Co

✷ Hincksia mitchelliae (Harv.) P. C. Silva Myrionemataceae ■ Myrionema strangulans Grev. Scytosiphonaceae Colpomenia sinuosa (Roth) Debrès & Solier

PHAEOPHYTA Ectocarpaceae ✷ Ectocarpus elachistaeformis Heydr.

Taxa

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

3

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο Ο

Ο

Ο Ο

Ο

Ο

Ο

Ο Ο

P

R

T

Q

T

P1

T

T

E

I

E

T

P

G

P

P

Ill. Months 5 6 9

Table 1. Phaeophyta and Chlorophyta identified from deep-waters off the southwest shore Cozumel Island, Mexico. ✷ Indicates new records for the island of Cozumel. ■ indicates new records for Mexico. References to illustrations and descriptons of each taxon are listed using the following letters: A. Barton (1901), B. Bø rgesen (1913), C. Bø rgesen (1920), D. Diaz Piferrer (1965), E. Earle (1969), F. Eiseman & Earle (1982), G. Fletcher (1987), H. Harvey (1858), I. Henry (1987), J. Hillis-Colinvaux (1980), K. Hö rnig & Schnetter (1988), L. Littler & Littler (1990), M. Littler & Littler (1992), N. Littler & Littler (1997), O. Ortega (1995), P. Schneider & Searles (1991), Q. Schnetter (1976), R. Setchell (1926), S. Silva (1952), T. Taylor (1960), U. Taylor (1962). Reefs: PN—Paraiso North, Ch—Chankanab, To—Tormentos, Y—Yucab, Tu—Tunich, SF—San Francisco, SR—Santa Rosa, P—Palancar, Co—Colombia. Months: 3—March, 5—May, 6—June, 9—September. Ill.: Illustrations. 122 BULLETIN OF MARINE SCIENCE, VOL. 66, NO. 1, 2000

■ Phyllodictyon pulcherrimum J. E. Gray

Cladophora vagabunda (L.) C. Hoek Boodleaceae

■ Cladophora albida (Nees) Kü tz. Cladophora catenata (L.) Kü tz.

■ Microdictyon marinum (Bory) P. C. Silva Cladophoraceae Chaetomorpha linum (O. F. Mü ll.) Kü tz.

■ Anadyomene saldanhae A. B. Joly & E. C. Oliveira Anadyomene stellata (Wulfen) C. Agardh

■ Entocladia ventriculosa Bø rgesen Anadyomenaceae

✷ Entocladia viridis Reinke

Ulvellaceae

×

×

×

×

18−24

27

8− 27 ×

21−30

10−15

× ×

×

×

× ×

12−27 12−30 ×

×

×

×

×

×

× ×

12−30

18

×

×

×

×

×

12−18 ×

Sargassum vulgare C. Agardh

CHLOROPHYTA

×

×

10−24 ×

× ×

×

8−15 10−27

Padina sanctae-crucis Bø rgesen

×

Stypopodium zonale (J. V. Lamour.) Papenf. Sargassaceae Sargassum filipendula C. Agardh

×

×

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

21−24

×

Padina boergesenii Allender & Kraft

× Ο

×

8− 30 ×

■ Dictyota pulchella Hö rnig & Schnetter Lobophora variegata (J. V. Lamour.) Womersley ex E. C. Oliveira ×

3 Ο

Depth Reefs (m) PN Ch To Y Tu SF SR P Co 8−30 × × × × × × ×

Taxa

Table 1. Continued.

Ο

Ο

Ο

Ο

Ο

Ο

Ο

P

T

S

T

P

C3

P

T

T

T

E

T2

P

P5

P

Ο T4

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο Ο

Ill. Months 5 6 9 Ο Ο Ο K MENDOZA-GONZÁLEZ ET AL.: NEW RECORDS OF BENTHIC MARINE ALGAE FROM MEXICO

123

× ×

12−21 12−30 12−15 8−30 × 10−15

✷ Caulerpa cupressoides (H. West) C. Agardh var. turneri Weber Bosse

Caulera mexicana Sond. ex Kü tz.

✷ Caulerpa mexicana Sond. ex Kü tz. f. pectinata (Kü tz.) W. R. Taylor

✷ Caulerpa microphysa (Weber Bosse) Feldmann

Caulerpa paspaloides (Bory) Grev.

8−30 ×

×

×

×

× ×

×

×

×

×

×

18−27

✷ Codium taylorii P. C. Silva Caulerpaceae Caulerpa cupressoides (H.West) C. Agardh

18−21

×

8−27

×

18−27

■ Derbesia vaucheriaeformis (Harv.) J. Agardh

■ Trichosolen blomquistii (Dí az-Pif.) D. M. John

■ Trichosolen duchassaingii (J. Agardh) W. R. Taylor Codiaceae Codium isthmocladum Vickers

×

18−27

×

× ×

×

24−27

×

Derbesia marina (Lyngb.) Solier

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

8−24

×

×

18−21

Valonia utricularis (Roth) C. Agardh Bryopsidaceae Bryopsis pennata J. V. Lamour. ×

×

×

×

×

10−15

×

×

×

18−30

×

×

Valonia macrophysa Kü tz.

×

×

8−30 ×

×

Ventricaria ventricosa (J. Agardh) J. L. Olsen & J. A. West Valoniaceae Ernodesmis verticillata Bø rgesen ×

×

×

× ×

8−27 × ×

×

18−30

Dictyosphaeria cavernosa (Forrskål) Bø rgesen

Depth Reefs (m) PN Ch To Y Tu SF SR P Co

Siphonocladaceae Cladophoropsis macromeres W. R. Taylor

Taxa

Table 1. Continued.

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

3

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

T

T

Ο

T

T

P

P

U8

D7

H

P

P

T

T

Ο

Ο Ο

Ο

T

T

O

P

Ο N

Ο Ο

Ο

Ο

Ο

Ο

Ο

Ο Ο

Ο Ο T6

Ο Ο

Ο

Ill. Months 5 6 9

124 BULLETIN OF MARINE SCIENCE, VOL. 66, NO. 1, 2000

8−30 ×

10−27 12−21 12−14 × 24−27 15−18

Avrainvillea longicaulis (Kü tz.) G. Murray & Boodle

Avrainvillea nigricans Decne.

Avrainvillea rawsonii (Dickie) M. Howe

■ Boodleopsis pusilla (Collins) W. R. Taylor, A. B. Joly & Bernat.

✷ Halimeda copiosa Goreau & E. A. Graham

× 18−21

■ Halimeda tuna (J. Ellis & Sol.) J. V. Lamour. f. platydisca (Decne.) E. S. Barton

×

× 8−30

Halimeda tuna (J. Ellis & Sol.) J. V. Lamour.

×

18−30

Halimeda simulans M. Howe

×

×

8−30 ×

Halimeda opuntia (L.) J. V. Lamour.

×

×

10−21

Halimeda monile (J. Ellis & Sol.) J. V. Lamour.

×

×

×

×

×

×

×

×

×

×

12−24 ×

×

×

×

×

✷ Halimeda gracilis Harv. ex J. Agardh Halimeda incrassata (J. Ellis) J. V. Lamour.

×

×

8−30

✷ Halimeda discoidea Decne.

✷ Halimeda goreauii W. R. Taylor

21−27

×

12−30

18−21 18−21

18−24

■ Caulerpa webbiana Mont. Caulerpella ambigua (Okamura) Prud’ homme & Lokhorst Udoteaceae Avrainvillea elliotii A. Gepp & E. Gepp

Caulerpa verticillata J. Agardh

× ×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

M

T9

M

J

J

J

J

J

J

J

Ο Ο A

Ο Ο

Ο Ο

Ο Ο

Ο

Ο Ο

Ο Ο

J

J

P

Ο M

Ο Ο

Ο

Ο

T T

Ο M

Ο Ο Ο

T Ο N

Ο

T

Ο Ο N

×

× Ο

×

×

✷ Caulerpa racemosa (Forsskå l) J. Agardh var. macrophysa (Sond. ex Kü tz.) W.R. Taylor 18−21 12−30 ■ Caulerpa serrulata (Forsskå l) J. Agardh Caulerpa sertularioides (S. G. Gmel.) M. Howe 10−15

×

✷ Caulerpa racemosa (Forsskå l) J. Agardh var. peltata (J. V. Lamour.) Eubank

×

×

12−27

Caulerpa racemosa (Forsskå l) J. Agardh ×

Ill. Months 3 5 6 9 Ο Ο Ο N

Taxa Depth Reefs (m) PN Ch To Y Tu SF SR P Co 18−30 × ×

Table 1. Continued


125

×

as Dictyopteris membranacea, 2 as Padina gymnospora, 3 as Endoderma ventriculosum, Pseudobryopsis blomquistii, 8 as Trichosolen antillarum, 9 as Caulerpa vickersiae

1

×

as Cladophora fulginosa,

8−27 ×

×

8−27 ×

4

×

12−27 12−27 ×

■ Udotea unistratea D.S. Littler & Littler

✷ Udotea wilsonii A. Gepp, E. Gepp & M. Howe Dasycladaceae Neomeris annulata Dickie Polyphysaceae Acetabularia crenulata J.V.Lamour.

×

18−24

✷ Udotea occidentalis A. Gepp & E. Gepp Udotea spinulosa M. Howe

×

5

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

as Struvea pulcherrima,

×

×

8−27

✷ Udotea loensis D. S. Littler & Littler

12−27 ×

×

×

18−30

×

×

×

8−27 ×

×

✷ Udotea dixonii D. S. Littler & Littler Udotea flabellum (J. Ellis & Sol.) J. V. Lamour.

×

×

×

12−30 ×

Udotea cyathiformis Decne.

Udotea cyathiformis Decne. var. cyathiformis f. sublittoralis (W. R. Taylor) D. S. Littler & Littler 12−15

×

×

8−30

Rhipocephalus phoenix (J. Ellis & Sol.) Kü tz. f. longifolius A. Gepp & E. Gepp

×

×

12−15

■ Rhipiliopsis profunda (Eiseman & S. Earle) J. N. Norris & J. L. Olsen Rhipocephalus oblongus (Decne.) Kü tz. ×

×

18−30 ×

×

×

12−27

■ Penicillus pyriformis A. Gepp & E. Gepp f. explanatus Bø rgesen

×

×

×

× ×

18−27 ×

×

Penicillus pyriformis A. Gepp & E. Gepp

×

10−21

×

×

■ Penicillus dumetosus (J. V. Lamour.) Blainv. f. expansus Bø rgesen Penicillus lamourouxii Decne. ×

×

6

×

×

×

×

×

×

×

×

×

×

×

×

×

×

×

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

3

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Ο

T

T

F

B

T

T

T

Ο

Ο

7

as

T

S

Ο M

Ο M

Ο M

Ο M

M

Ο M

Ο M

Ο M

Ο M

Ο

Ο

Ο

Ο

Ο

Ο

Ο

Months Ill. 5 6 9 Ο Ο T

as Valonia ventricosa,

Penicillus dumetosus (J. V. Lamour.) Blainv.

×

12−30

Penicillus capitatus Lam. 18−24

Depth Reefs (m) PN Ch To Y Tu SF SR P Co 12−30 × × ×

Taxa

Table 1. Continued 126 BULLETIN OF MARINE SCIENCE, VOL. 66, NO. 1, 2000


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pedicels, 8–15 μm long vs up to 120 μm long. This is the first report of this species outside of Puerto Rico. Caulerpa mexicana Sond. ex Kütz. f. pectinata (Kütz.) W. R. Taylor.—Erect axes of this form were 10–15 mm tall compared with the typical form that reaches 25 cm (Taylor, 1960) and Ortega’s report of form pectinata from Campeche, Mexico in which she illustrates plants over 50 mm tall. Taylor indicated that the pinnules in this form are separated by about their own width. In his original description of the form as a species, Kützing (1849) described plants with imbricate pinnules and in our collections from Cozumel the pinnules are generally slightly imbricate or at most are separated by one fourth of their width. Caulerpa racemosa (Forsskål) J. Agardh var. peltata (J. V. Lamour.) Eubank.—Included in our collections are specimens of Caulerpa with the morphology of plants described as C. racemosa var. laetevirens (Mont.) Weber Bosse. Ohba & Enomoto (1987) and Ohba, Nashima, & Enomoto (1992) demonstrated that the same isolates expressed the “laetevirens” morphology in high light and low temperatures, and the “peltata” morphology in low light and high temperature conditions. Wynne (1998) indicated that plants with either the “laetevirens” morphology (branchlets cylindrical or clavate and imbricate) or with the “peltata” morphology (branchlets peltate) should be referred to as var. peltata since the name has priority over var. laetevirens. Caulerpa racemosa var. macrophysa (Sond. ex Kütz.) W. R. Taylor.—In the Caribbean, this variety of Caulerpa racemosa, characterized by widely spaced, obconical branchlets with hemispherical to slightly convex tips, has been reported from the Yucatán peninsula by Garza Barrientos (1975, 1998). The only other record of the variety is Taylor’s (1928) from Florida. It was collected only once in this study. Halimeda spp.—All five of the Halimeda’s reported here as new records for Cozumel or Mexico were also found in even deeper waters by Blair and Norris (1988) in their records of deep water Halimeda from the Bahamas. Halimeda goreauii was by far the most common species of Halimeda observed in deeper waters off Cozumel. Penicillus capitatus Lam.—Collections of Penicillus included diminutive specimens only 3.5 cm tall with capitular filaments as small as 76 μm diameter. No species of Penicillus has been described with such slender capitular filaments. The narrowest capitular filaments reported for the genus are those of P. capitatus (125–300 μm) and P. pyriformis A. Gepp & E. Gepp (150–250 μm) (Taylor, 1960). The much smaller size of these Cozumel plants suggested that they might be an unreported species. However, the corticating filaments of the stalks of these small plants were truncated with thickened end walls as described and illustrated for P. capitatus. Examination of over 100 plants of Penicillus with the stalk characteristics of P. capitatus in the collections at Duke University and the U.S. National Herbarium from around the Caribbean indicate that P. capitatus has a much larger range of plant sizes and diameter of capitular filaments than previously reported. Height of plants from the base of the stalk to the end of the capitulum ranged from less than 2 cm to 22 cm; diameter of capitular filaments ranged from 76 to 295 μm. There were no apparent discontinuities in the distribution of either of these dimensions across the collections or any localization geographically of small or large plants. These observations suggest that these Mexican specimens, as well as similar small plants from other parts of the Caribbean, are not a new species but that P. capitatus includes smaller and larger plants with narrower and broader capitular filaments than previously reported. Penicillus dumetosus (J. V.Lamour.) Blainv. f. expansus Børgesen.—Plants we have ascribed to this form have stalks 2 cm long and capitula 11 cm long. Described by Børgesen

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(1913) from deep-water (30 m) in the Danish West Indies (U.S. Virgin Islands), this form has very short stalks of 2–4 cm with capitula of 14–17 cm length (Taylor, 1960). Taylor also indicated that all records of the species except form expansus were from shallow depths (3.7 m or less). We find no records of this form in the Caribbean since Børgesen’s original description. Penicillus pyriformis A.Gepp & E.Gepp f. explanatus Børgesen.—This is another of Børgesen’s (1913) forms from deep-water (40 m) that has not been recorded since his original report. It has a broad, flattened capitulum whose filaments are loosely entangled rather than tightly compacted as in the typical form. Rhipiliopsis profunda (Eiseman & S. Earle) J. N. Norris & J. L. Olsen.—Norris and Olsen (1991) transferred this species from the monotypic genus Johnson-sea-linkia Eiseman & S. Earle to Rhipiliopsis A. Gepp & E. Gepp. Previous records of this species are restricted to the Bahamas and Puerto Rico. All specimens previously collected were obtained from depths between 55 and 153 m either using submersibles or by dredging. The plants collected at Cozumel from 27–30 m are therefore both geographically distant from other records of the species and are at much shallower depths. This is a very common plant under overhanging ledges and other low light environments at Columbia and Palancar Reefs. Udotea cyathiformis Decne.—Littler and Littler (1990) described the variety flabellifolia for plants from deep water (20–40 m) forming fan-shaped rather than cup-shaped or scoop-shaped blades. Included in the list of representative specimens cited by Littler and Littler are plants from North Carolina in the US National Herbarium. Examination of the collections of the species from North Carolina waters at DUKE, e.g,. No. 11898, and observations by one of us (RBS) in the field indicate that specimens from small patches, probably representing a single clonal plant, include both cup-shaped and fan-shaped blades. This suggests that the morphology distinguishing the variety flabellifolia is a case of phenotypic variability, not a genetic difference among plants and although our collections from Cozumel include plants with the morphology of the variety flabellifolia we chose not to recognize it. Udotea dixonii D. S. Littler & Littler.—Littler and Littler (1990) indicate that this species is restricted to low light environments, 15–54 m depths, or shallower, shaded habitats. We collected it in open, unshaded depths as shallow as 8 m at Paraiso North. Udotea unistratea D. S. Littler & Littler.—Littler and Littler (1990) suggested that this species will probably turn out to be widely distributed, but because of its restriction to deep water, 24–46 m in their collections, it will not often be collected. We have collections from somewhat shallower water, but still not in depths accessible except by SCUBA diving. Udotea wilsonii A. Gepp, E. Gepp, & M. Howe in A. Gepp & E. Gepp.—The representative specimens of this species listed by Littler and Littler (1990) are from relatively shallow depths, to 10 m. All of our collections are from deeper water, 12–27 m. ACKNOWLEDGMENTS Permission to collect in the restricted waters of Cozumel was provided by the Secretaria de Medio Ambiente, Recursos Naturales y Pesca of Mexico (SEMARNAP). Logistical support was provided by the Secretaria de Marina de Mexico. This study would not have been possible without the diving assistance of E. Krellwitz, R. Robles, S. Ross, and M. Volovsec. The Duke University


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Research Council provided funds for travel and diving equipment rental. Funding for the first author was provided by a grant from the Comision de Operación y Fomento de Actividades Academicas del Instituto Politécnico Nacional (COFAA, IPN). L. Huerta M. of the Escuela Nacional de Ciencias Biología, I.P.N. provided laboratory space, obtained permission to make the collections and gave wise council.

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__________ and A. Garza-Barrientos. 1980. Contribución al conocimiento de la flora marina de la zona sur del litoral de Quintana Roo, Mexico. An. Esc. Nac. Cienc. Biol. Méx. 23: 25–44. __________, A. C. Mendoza-González and L.E. Mateo-Cid. 1987. Avance sobre un estudio de las algas marinas de la peninsula de Yucatán. Phytologia 62: 23–53. Kraft, G. T. and M. J. Wynne. 1996. Delineation of the genera Struvea Sonder and Phyllodictyon J. E. Gray (Cladophorales, Chlorophyta). Phycol. Res. 14: 129–142. Kützing, F. T. 1849. Species algarum. Pp. i-vi, 1–922. Leipzig. Lewbel, G.S. and L.R. Martin. 1991. Diving and snorkeling guide to Cozumel 2nd ed. Pices Books. vi + 90 p. Littler, D. S. and M. M. Littler. 1990. Systematics of Udotea species (Bryopsidales, Chlorophyta) in the tropical western Atlantic. Phycologia 29: 206–252. __________ and __________. 1992. Systematics of Avrainvillea (Bryopsidales, Chlorophyta) in the tropical western Atlantic. Phycologia 31: 375–418. __________ and __________. 1997. An illustrated marine flora of the Pelican Cays, Belize. Proc. Biol. Soc. Wash. 9: 1–149. Mateo-Cid, L. E. and A. C. Mendoza-González. 1991. Algas marinas benticas de la Isla Cozumel, Quintana Roo, Mexico. Acta Bot. Mex. 16: 57–87. Norris, J. N. and J. L. Olsen. 1991. Deep-water green algae from the Bahamas, including Cladophora vandenhoekii sp. nov. (Cladophorales) Phycologia: 30: 315–328. Ohba, H. and S. Enomoto. 1987. Culture studies on Caulerpa (Caulerpales, Chlorophyta). II. Morphological variation of C. ramosa var. laetevirens under various culture conditions. Jap. J. Phycol. 35: 178–188. ______, H. Nashima and S. Enomoto. 1992. Culture studies on Caulerpa (Caulerpales, Chlorophyceae) III. Reproduction, development and morphological variation of laboratorycultured C. racemosa var. peltata. Bot. Mag. Tokyo 105: 589–600, 27 figs. Ortega, M. M. 1995. Observationes del fitobentos de la Laguna de Términos, Campeche, México. Anal. Inst. Biol. Univ. Nac. Autón. Méx., Ser. Bot. 66: 1–36. Schneider, C.W. & R.B. Searles. 1991. Seaweeds of the southeast United States. Cape Hatteras to Cape Canaveral. Duke Univ. Press, Durham. xiv + 553 p. Schnetter , R. 1969. Marine Algen der karibischen Küsten von Kolumbien. I. Phaeophyceae. Biblioth. Phycol. 24: 1–125. Setchell, W. A. 1926. Tahitian algae collected by W. A. Setchell, C. B. Setchell and H. E. Parks. Univ. Calif. Publs. Bot. 12: 61–142, pls. 7–22. Silva, P. C. 1952. The identity of Hydrodictyon marinum Bory. Rev. Algol. n.s. 1(4): 179–180. ________, P. Basson and R. Moe. 1996. Catalogue of benthic marine algae of the Indian Ocean. Univ. Calif. Publs. Bot. 79: xiv + 1259 p. Taylor, W. R. 1928. The marine algae of Florida with special reference to the Dry Tortugas. Publs Carn. Inst. Wash. 379: [i–v], 1–219, 37 pls. __________. 1960. Marine algae of the eastern tropical and subtropical coasts of the Americas. Univ. Michigan Press, Ann Arbor. i*–xi, 1–879. __________. 1962. Observations on Pseudobryopsis and Trichosolen (ChlorophyceaeBryopsidaceae) in America. Brittonia 14: 58–65, 25 figs. __________. 1972. Marine algae of the Smithsonian-Bredin expedition to Yucatán -1960. Bull. Mar. Sci. 22: 34–44. Wynne, M. J. 1998. A checklist of benthic marine algae of the tropical and subtropical western Atlantic: first revision. Nova Hedwigia 116: I–III, 1–155. DATE SUBMITTED: January 5, 1999.

DATE ACCEPTED: May 21, 1999.

ADDRESSES: (C.M.-G., L.E.M.-C.) Laboratorio Ficología, Departamento de Botánica, Escuela Nacional de Ciencias Biológicas, I.P.N., Prol. Carpio y Plan de Ayala, 11340 México, D.F., Mexico. CORRESPONDING AUTHOR: (R.B.S.) Duke University, Department of Botany, Box 90338, Durham, North Carolina 27708-0338. e-mail: .