Udotea occidentalis A. Gepp & E.S. Gepp 1911: 127

Acosta-Calderón, Julio Adulfo, Hernández-Rodríguez, César, Mendoza-González, Ángela Catalina & Mateo-Cid, Luz Elena, 2018, Diversity and distribution of Udotea genus J. V. Lamouroux (Chlorophyta, Udoteaceae) in the Yucatan peninsula littoral, Mexico, Phytotaxa 345 (3), pp. 179-218 : 206

Udotea occidentalis A. Gepp & E.S. Gepp 1911: 127

Type locality:— USA. St. Thomas, Virgin Islands.

Morphology:—Thalli to 5 cm, anchored on soft substrata by a bulbous mass of rhizoids. Stipe cylindrical, robust, 8–10 mm length, 5–6 mm diameter, there is no differentiation between stipe and blade. Blade fan-shaped, multilobed, light green, wider (7–8 cm) than long (4–5 cm, lower margin is reniform, multistratose, corticated, heavily calcified, and fain concentric zonation ( Fig. 70 ).

Anatomy:—Blade siphons with lateral appendages, 30–40 μm in diameter, densely covered by two opposite rows of short lateral appendages ( Fig. 71 ), possessing 8–15 low unique knobs with appearances of sunken blade appendages, peduncle 10–20 μm in diameter, 40–65 μm length ( Fig. 72 ). Stipe siphons adjacent to lateral appendages 30–60 μm in diameter, appendages peduncle 150–300 μm length, 20–30 μm in diameter. Appendages branched twice terminating in numerous rounded projections ( Fig. 73 ).

Reproduction:—Vegetative

Material examined: — MEXICO. Quintana Roo, Chankanab, Isla Cozumel, 15 May 1993, R. B. Searles, M. Volovseck, ENCB 12766

Geographic distribution:— Bermuda, Florida, Belize, Bahamas, Cuba, Puerto Rico, Virgin Islands, Brazil, Philippines, Mexico

Habitat:—Sandy bottom, subtidal to 12–15 m depth

Comments:— Gepp & Gepp (1911) described for the first time Udotea occidentalis based in morphological and anatomical character record from West Indies specimens. Littler & Littler (1990) mention that U. occidentalis can be confused with Udotea flabellum by the corticate blade; however both species can be differentiated by the presence of the fan-shape blade with a lower margin cordate and the uniquely lobed blade appendages. This species has been reported in depths greater than 5 m (Geep & Geep 1911, Littler & Littler 1990). This species was not located by the collections carried out in this study; hence, specimens from the ENCB herbarium were consulted to corroborate the record in the Yucatan peninsula littoral.

Figures

FIGURES 70–73. U. occidentalis. 70) external morphology, 71) blade siphons showing the lateral appendages arrangement, 72) blade lateral appendages, 73) stipe lateral appendage. FIGURES 74–76. U. spinulosa. 74) external morphology, 75) blade lateral appendages, 76) stipe lateral appendage. FIGURES 77–78. U. unistratea. 77) external morphology, 78) blade siphons.