Udotea dotyi D. S. Littler & M. M. Littler (1990: 223)

Rocha, Mayara C. B. S., Pereira, Sonia M. B., Oliveira-Carvalho, Maria F., Benko- Iseppon, Ana M., Ximenes, Caroline F., Fujii, Mutue T. & Cassano, Valéria, 2023, Morphological and molecular characterization of Udotea species (Bryopsidales, Chlorophyta) from northeastern Brazil with a new record of U. dotyi from the western south Atlantic, Phytotaxa 578 (1), pp. 57-74 : 65

Udotea dotyi D. S. Littler & M. M. Littler (1990: 223)

( Fig. 7–14 )

Type locality: Tobago Cays , Grenadines, Lesser Antilles

Description: Thallus erect, light green to dark green, strongly calcified, leathery, growing isolated, up to 10 cm high, attached to the substratum by a bulbous basal portion composed of a rhizoidal mass ( Figs 7–9 ). Stipe short, flattened or cylindrical, strongly calcified, rigid, up to 1 cm long and up to 5 mm wide. Transition between stipe and blade not evident. Blade flabellate or occasionally lobed, sometimes spatulate or flabellate-truncate in lower margin ( Figs 7–9 ), surface flat, multistratose, corticated, with visible concentric zonation, up to 9 cm long. Blade siphons with lateral appendages, siphons cylindrical densely compacted, constrictions above the dichotomies absent, 20–50 µm wide. Lateral appendages densely distributed, often unilaterally ( Figs 10, 11 ) or disposed in a pattern opposite or irregular on the siphons; appendages with short stalks; appendages stalk 40–100 μm long, 20–30 μm in diameter very branched forming a closely packed flattened tips ( Figs 11, 12 ). Stipe siphons with lateral appendages without constrictions at the base, siphons interwoven, longitudinally arranged, 40–70 µm in diameter sparsely distributed irregularly on the siphons ( Figs 13, 14 ); appendages with long stalks, appendages stalk 130–350 μm long, 20–50 μm in diameter, dichotomously branched, with rounded swollen tips ( Fig. 14 ). Fertile specimens were not found.

Material examined: BRAZIL. Pernambuco: Goiana, Ponta de Pedras , 07°36’41”S, 34°48’30”W, 27 May 2017, M. F . Oliveira-Carvalho ( UFP83634 ); Itamaracá, Pilar , 07°45’20.04”S, 34°49’17.25”W, 26 April 2017, M. F . OliveiraCarvalho , M. C. B. S . Rocha , C. F . Ximenes ( UFP83564 ), GenBank accession: tuf A OK623532 , rbc L OK623528 , 20 August 2016, M. F . Oliveira-Carvalho ( UFP83565 ); Itamaracá, Jaguaribe , 07°44’12’’S, 34°49’24”W, 29 August 2016, M. F . Oliveira-Carvalho , M. C. B. S . Rocha , C. F . Ximenes ( UFP83448 ), GenBank accession: tuf A OK623533 , rbc L OK623529 ; Candeias , 08°12’22”S, 34°55’01”W, 28 April 2017, M. F . Oliveira-Carvalho ( UFP83584 ); Itapuama , 08°17’38”S, 34°57’05”W, 21 May 2017, M. F . Oliveira-Carvalho ( UFP83585 ); Cabo de Santo Agostinho, Suape , 8°21’36.15”S, 34°57’15.17”W, 21 July 2017, M. F . Oliveira-Carvalho ( UFP83586 ), 21 May 2016, M. F . OliveiraCarvalho , M. C. B. S . Rocha , C. F . Ximenes ( UFP83587 ), GenBank accession: tuf A OK623531 , rbc L OK623527 ; Serrambi , 08°33’37.35”S, 35°0’58.91”W, 02 July 2016, M. F . Oliveira-Carvalho ( UFP83580 ), 27 April 2017, M. F . OliveiraCarvalho ( UFP83579 ); Tamandaré, Carneiros , 08°42’9.56”S, 35°4’49.74”W, 22 July 2016, M. F . Oliveira-Carvalho , M. C. B. S . Rocha , C. F . Ximenes ( UFP83467 ), GenBank accesion: tuf A OK623534, OK623535 , rbc L OK623526 . Alagoas: Maragogi, Praia de Maragogi , 09°00’43.2’’S, 35°13’19.2’’W, 13 March 2012, F . Scherner, 4 m depth ( PEUFR52367 ), GenBank accession: rbc L OK623530 . Ceará: Paracuru, Pedra Rachada , 3º23’55”S, 39º00’44”, 27 July 2013, M. F . Oliveira-Carvalho ( PEUFR52376 ), GenBank accession: rbc L OK623525 .

Habitat: Specimens were found growing on sandy substratum in the intertidal zone or, more rarely, on rocky in calm areas. Also found in subtidal zone at 4 m depth.

Remarks: The analyzed Brazilian specimens of Udotea dotyi showed great external morphological plasticity regarding the blade shape but sharing the multistratose blades with zonation, and continuous stipe-blade junction. Our specimens agree with the dimensions of the thallus and blade by Acosta-Calderón et al. (2018), differing only by the longer stipe (up to 1 cm long vs. 8–13 mm, Acosta-Calderón et al. 2018). The diameter of blade siphons and stipe siphons are almost perfectly within the range found by Acosta-Calderón et al. (2018, 20–40 μm in diam. and 40–70 μm in diam., respectively). However, Brazilian specimens did not present blade siphons covered by appendages predominantly opposite as described by Littler & Litter (1990) and Acosta-Calderón et al. (2018), being often unilateral in our specimens ( Table 3 ). Despite gross morphology and anatomical variations, Brazilian specimens correspond to U. doty i based on our molecular results. Most of our specimens were found only in the intertidal zone, growing on sandy substratum, nevertheless U. dotyi from Alagoas state occurred from the intertidal to subtidal zones up to 4 m depth. As our specimens, U. dotyi from the Gulf of Mexico grows from intertidal (on sandy bottom) to subtidal to 3 m depth ( Acosta-Calderón et al. 2018), whereas the most specimens from the Caribbean Sea are often collected from moderately deep at 12–25 m ( Littler & Littler 1990).

Figures

FIGURES 3–14. ‘Udotea cyathiformis’. 3. External morphology. 4. Detail of the blade siphon showing dichotomies with constrictions. 5–6. Detail of the stipe lateral appendages. Udotea dotyi. 7–9. Variation of external morphology.10. Blade siphon showing arrangement of lateral appendages. 11. Detail of the blade siphon showing unilateral appendages. 12. Detail of blade lateral appendages. 13–14. Details of the stipe lateral appendages.