Udotea flabellum (J. Ellis & Solander) M.A. Howe 1904: 94

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 : 201-203

Udotea flabellum (J. Ellis & Solander) M.A. Howe 1904: 94

Basionym:— Corallina flabellum J. Ellis & Solander 1786

Heterotypic Synonyms:— Udotea flabellata J.V. Lamouroux 1816

Type Locality:— WEST INDIES.

Morphology:—Thalli to 10 cm tall, anchored on substrata by a bulbous to elongated mass of fibrous rhizoids. Stipe cylindrical, short and robust or thin, flattening toward the blade, 5–47 mm length, 3–6 mm diameter. Transition between the stipe and blade is not evident. Blade fan-shaped with many overlapping lobes, dark green, almost wider (2.5–10 cm) than longer (2–8.7 cm), lower margin ovate or truncate, multistratose, ecorticate, heavily calcified, and marked by distinct concentric zonation lines (Figs. 50–53).

Anatomy:—Blade siphons with lateral appendages, dichotomously branched, 20–30 μm in diameter, blade appendages arranged irregularly spaced long-stemmed, terminating in many, short, dichotomously branched projections, apices swollen and flat ( Fig. 54 ), blade appendages peduncle 12–21 μm in diameter, 60–150 μm in length. Stipe siphons adjacent to lateral appendages 27–60 in diameter, peduncle 120–480 μm length, 25–45 μm in diameter. Appendages branched twice, with dichotomously small tips ( Fig. 55 ).

Reproduction: — The terminal portion of the fertile frond becomes loose, and as the filaments separate the reproductive structure can be observed.

Material examined:— MEXICO. Quintana Roo, Santa Rosa, 11 June 2014, J. A. Acosta Calderón, L. E. Mateo Cid, A. C. Mendoza González, ENCB 23146. MEXICO. Quintana Roo, Uvero, 10 June 2014, J. A. Acosta Calderón, Mateo Cid, A. C. Mendoza González, ENCB 23139. MEXICO. Quintana Roo, Punta Rio Bermejo, 12 April 2015, J. A. Acosta Calderón, Mateo Cid, A. C. Mendoza González, ENCB 23145. MEXICO. Quintana Roo, Rio Indio, 11 September 2014, J. A. Acosta Calderón, Mateo Cid, A. C. Mendoza González, ENCB 23138. MEXICO. Quintana Roo, Punta Akumal, 16 December 2014, J. A. Acosta Calderón, L. E. L. E. Mateo Cid, A. C. Mendoza-González, ENCB 23147. MEXICO. Quintana Roo, Akumal, 24 December 2002, L. Huerta Múzquiz, A. C. Mendoza González, ENCB 16177. MEXICO. Yucatán, Santa Clara Pueblo, 20 June 2011, J. A. Acosta Calderón, L. E. Mateo Cid, A. C. Mendoza-González, ENCB 23140. MEXICO. Yucatán, Progreso, 15 December 2014, J. A. Acosta Calderón, L. E. Mateo Cid, A. C. Mendoza-González, ENCB 23141. MEXICO. Yucatán, Ria Lagartos, 22 November 1997, L. Huerta Múzquiz, I. Sánchez Molina, R. Rojas, ENCB 13494. MEXICO. Yucatán, San Crisanto, 23 June 2006, L. E. Mateo Cid, A. C. Mendoza González, ENCB 18501. MEXICO. Campeche, Punta Xen, 26 June 2014, J. A. Acosta Calderón, L. E. Mateo Cid, A. C. Mendoza-González, ENCB 23144. MEXICO. Campeche, Xpicob, 25 June 2016, J. A. Acosta Calderón, L. E. Mateo Cid, A. C. Mendoza-González, ENCB 23143. MEXICO. Campeche, La Ensenada, 27 June 2016, J. A. Acosta Calderón, L. E. Mateo Cid, A. C. Mendoza-González, ENCB 23137. MEXICO. Campeche, Puerto Real, 26 January 2016, J. A. Acosta Calderón, L. E. Mateo Cid, A. C. Mendoza-González, ENCB 23142. MEXICO. Campeche, 26 January 2016, J. A. Acosta Calderón, L. E. Mateo Cid, A. C. Mendoza González, ENCB 23142. MEXICO. Campeche, Playa Bonita, 19 April 2007, L. E. Mateo Cid, A. C. Mendoza González, ENCB 22811.

Geographic distribution: — Bermuda, Florida, Belize, North Carolina, Texas, Panama, Bahamas, Caiman Island, Cuba, Jamaica, Lesser Antilles, Puerto Rico, Trinidad and Tobago, Brazil, Colombia, Venezuela, Kenya, Somalia, Tanzania, India, Sri Lanka, China, Indonesia, Malaysia, Philippines, Tailand, Vietnam, New Zealand, Mexico.

Habitat:—Rocky platforms with soft waves, sandy bottom with sea grass meadows, reef lagoons. Subtidal to 5 m depth.

Comments:—The first morphological description of this species was made by J. Ellis & Solander (1786), as Corallina flabellum . Later, Lamouroux (1816) made the change from C. flabellum to Udotea flabellata . Howe (1904) made the combination Udotea flabellum . Taylor (1960) provided information about the morphology of U. flabellum thalli. Finally, Littler & Littler (1900) provided a detailed description of the morphological and anatomical characters used in the species segregation in this genus. In this study, U. flabellum may have a short and wide stipe or cylindrical, flattening toward the blade, however the shapes of the blade and stipe appendages are constant characters. This species can be confused with U. dotyi , U. dixonii , U. norrisii , and U. occidentalis by the blade morphology; however, the internal structure separates these five species. The shape of the blade and stipe appendages agrees with those described by Taylor (1960) and Littler & Littler (1990). Nevertheless, the diameter of blade siphons is less than those recorded in specimens from Florida, USA ( Littler & Littler 1990). But similar than those record from Quintana Roo, Mexico ( Collado-Vides et al. 2009). It is the most widespread species of Udotea in the Yucatan peninsula littoral.

Figures

FIGURES 52–55. U. flabellum. 52–53) external morphology, 54) blade lateral appendages, 55) stipe lateral appendages. FIGURES 56–59. U. looensis. 56–57) external morphology, 58) detail of the supradichotomic constriction of the blade siphon, 59) stipe lateral appendage. FIGURES 60. U. luna. 60) external morphology.