Gelidium calidum Jamas, Iha & M.T.Fujii, 2017

Jamas, Mayra, Iha, Cintia, Oliveira, Mariana C., Guimarães, Silvia M. P. B. & Fujii, Mutue T., 2017, Morphological and molecular studies on Gelidiaceae and Gelidiellaceae (Gelidiales, Rhodophyta) from Brazil with description of the new species Gelidium calidum, Phytotaxa 314 (2), pp. 195-218 : 207-208

Gelidium calidum Jamas, Iha & M.T.Fujii , sp. nov.

Figs. 8 and 9

Diagnosis:—Plants tufted or isolated, dark vinaceous-red, cartilaginous, up to 3.5 cm tall, arising from stoloniferous branches attached to the substratum by brush-like haptera. Erect axes are mainly flattened to compressed and proximally terete, sparse to abundantly branched. Branches slightly constricted at the base, and the apices are obtuse with prominent apical cells. Rhizines are abundant and scattered in the medulla or rarely between the medulla and the inner cortex. Tetrasporangial sori develop mainly on the apical portions of branches. Sterile margins are absent, or small rounded margins are present. Mature tetrasporangia are ovoid, cruciately divided. Cystocarps are bilocular and develop at the tips of penultimate or ultimate branchlets.

Holotype:— Ponta Grossa Beach , Icapuí, Ceará, Brazil. 27 April 2013, C. A. Azevedo & T. Vieira-Pinto. ( SP469072 ). rbc L sequence = GenBank accession number KX555612. cox 1 sequence = GenBank accession number KX574736.

Distribution:—Distributed throughout northeastern Brazil and collected in the states of Piaui, Ceará, Rio Grande do Norte, Pernambuco, and Bahia. Samples were collected in the intertidal region in sandstone reefs and rocky shore.

Etymology:—Latin: calidum = hot. The specific epithet calidum refers to its occurrence in the northeastern Brazil, which is characterized by a tropical climate.

Extended description: — Plants tufted or isolated, dark red-vinaceous, cartilaginous, up to 3.5 cm tall ( Fig. 8 ), arising from stoloniferous branches attached to the substratum by brush-like haptera ( Fig. 9 C, D ). Erect axes are mainly flattened to compressed and proximally terete, sparse to abundantly branched. Branches slightly constricted at the base, and apices are obtuse with prominent apical cells ( Fig. 9 A ). Stoloniferous branches are cylindrical, 170–300 μm in diameter, composed of a medulla with six to seven layers of colorless cells surrounded by three to four layers of pigmented cortical cells. Rhizines are scattered throughout the medulla to inner cortex. Cylindrical portions of the erect axes are 170–330 μm in diameter, and compressed portions are 85–210 μm thick and 307–345 μm wide. Flattened thalli are 45–135 μm thick and 385–1290 μm wide. In transverse section of the middle region of the main branch, medulla is composed of four to nine layers of cells in compressed regions and three to four layers of loosely arranged cells in flattened regions, 6–13 μm in diameter, surrounded by three to four layers of cortical cells ( Fig. 9 B ). Outermost cortical cells are cylindrical, 5–10 μm in diameter, to elliptical, 3–6 μm thick and 6–13 μm wide. Rhizines are abundant and scattered in the medulla or, rarely, between the medulla and the inner cortex. Tetrasporangial sori develop mainly on the apical portions of branches ( Fig. 9 E ). They either have no sterile margins, or they have small rounded margins ( Fig. 9 F ). Mature tetrasporangia are ovoid, 16–30 μm long and 23–52 μm wide, cruciately divided ( Fig. 9 F ). Cystocarps are bilocular and develop at the tips of penultimate or ultimate branchlets ( Fig. 9 G, H ), with one ostiole in each side of the thallus. Male gametophytic thalli were not observed.

Specimens examined: — Brazil. Piauí: Luis Correia, Pedra do Sal Beach, 22. June. 2013, col. M. T. Fujii ; D. Milstein ( SP 469080 ), 26. June. 2013, col. M. T. Fujii ; D. Milstein ( SP 469081 ). Ceará: Camocim, Farol Beach, 24. June. 2013, col. M. T. Fujii ; D. Milstein ( SP 469082 ) ; Paracuru, Munguba Beach, 24. April. 2013, col. B. N. Torrano-Silva, C. A. A. Azevedo , T. Vieira-Pinto ( SP 469071 ) ; Icapuí, Ponta Grossa Beach, 27. April. 2013, C. A. A. Azevedo ; T. Vieira-Pinto ( SP 469072 ). Rio Grande do Norte: Conde, Jacumã Beach, 18. October. 2012, col. S. M. P. B. Guimarães ( SP 469073 ) ; São Miguel do Gostoso , Cardeiro Beach, 29. March. 2014, col. M. Jamas, M. T. Fujii, D. Milstein, A. Santos, T. Vieira-Pinto ( SP 469074 ), Tourinhos Beach, 29. March. 2014, col. M. Jamas, M. T. Fujii, D. Milstein, A. Santos, T. Vieira-Pinto ( SP 469075 ). Pernambuco: Ipojuca, Toquinho Beach, 17. April. 2013, col. M. T. Fujii ( SP 469076 ). Bahia: Camaçari, Jauá Beach, 23.May.2013, col. M. Jamas, B. N. Torrano-Silva, C. A. A. Azevedo, T. Vieira-Pinto ( SP 469077 ). Porto Seguro, Espelho Beach, 12.May.2014, col. B. N. Torrano-Silva, J. Pires, A. S. Santos ( SP 469078 ) .

Based on sequence divergences between Gelidium crinale and G. calidum found for cox 1, 5.3–6.4%, and rbcL, 0.9–1.0%, and high support of the monophyletic clades in the analyses, we consider that they are two distinct species.

Figures

FIGURE 8. A–C. Variation in gross morphology for Gelidium calidum Jamas, Iha, M.T. Fujii sp. nov. in Brazil. Scale bar = 1 cm. A–B. Abundantly branched (SP469073, SP469072). C. Slightly branched (SP469074).

FIGURE 9. Gelidium calidum Jamas, Iha, M.T. Fujii sp. nov. (SP469074) A. Detail of the apical portion of the branch showing prominent apical cell (arrow). Scale bar = 25 μm. B. Cross section in the middle region of the vegetative branch. Scale bar = 50 μm. C. Stoloniferous branch with brush-like holdfast. Scale bar = 250 μm. D. Cross section of stoloniferous branch showing disorganized rhizoidal filaments produced by the internal cortical cells. Scale bar = 25 μm. E. Detail of the tetrasporangial branch. Scale bar = 250 μm. F. Cross section of tetrasporangial branch showing absence of sterile margin. Scale bar = 100 μm. G. Detail of female gametophyte branch with cystocarp. Scale bar = 250 μm. H. Cross section of the mature cystocarp with carposporangia produced in both sides of locule. Scale bar = 25 μm.