Udotea spinulosa M.A. Howe 1909: 97

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 : 206-208

Udotea spinulosa M.A. Howe 1909: 97

Type locality:— BAHAMAS. Bimini Harbor.

Morphology: — Thalli delicate to 4 cm tall, anchored on substrata by a small bulbous mass of entangled rhizoidal siphons. Stipe cylindrical, slightly calcified, 4–6 mm long, 0.5 mm in diameter. Gradual transition between the stipe and blade. Blade flabellate or spatulate, green, longer (2–2.5 cm) than wider (1.5–2 cm), lower margin obtuse, multistratose in most part of the blade and unistratose in the superior margin, corticated (with lateral appendages), calcified, and slightly zonate (Fig. 74).

Anatomy:—Blade siphons with lateral appendages except in unistratose margin, dichotomously branched, 30–45 μm in diameter, distance between each dichotomy varies from 1500 to 1600 μm. From each dichotomy, one of the siphons branches dichotomically and the other continues to grow without branching. Blade appendages have a short peduncle from which 1–8 spine-like projections arise (Fig. 75). Stipe siphons adjacent to lateral appendages 45–60 μm in diameter, appendages peduncle 40–80 μm length, 20–25 μm in diameter. Appendages dichotomously branched once, with long, acute, digitate projections (Fig. 76).

Reproduction: — Vegetative

Material examined:— MEXICO. Yucatan, Progreso, 20 June 2014, J. A. Acosta-Calderón, L. E. Mateo Cid, A. C. Mendoza González. ENCB 23179. MEXICO. Campeche, Playa Villamar, 25 January 2016, J. A. Acosta-Calderón, L. E. Mateo Cid, A. C. Mendoza González. ENCB 23182. MEXICO. Campeche, Don Lin, 22-06-2004, P. López, ENCB 16999.

Geographic distribution: — Florida, Bahamas, Jamaica, Puerto Rico, Virgin Island, Seychelles, Mexico.

Habitat: — Rocky bottom, subtidal to 5 m deep.

Comments: — Howe (1909) provide the first detail description of Udotea spinulosa based in morphological and anatomical characters of the blade and stipe. The shape of the stipe appendages agrees with those registered by Howe (1909), and Littler & Littler (1990). However, the diameter of siphons stipe and blade are smaller than those documented in specimens from Bahamas ( Howe 1909), Jamaica, Puerto Rico ( Littler & Littler 1990), and Cuba ( Collado-Vides et al. 2009). U. spinulosa has been cited for several localities from Quintana Roo, Campeche, and Yucatan shores, however in this study few specimens were found only in Progreso, Yucatan, and Playa Villamar, Campeche.