Chondrophycus anabeliae Sentíes, M.T. Fujii, Cassano & Dreckmann, 2016

Sentíes, Abel, Cassano, Valéria, Dreckmann, Kurt M., Gil-Rodríguez, Candelaria, Stein, Erika M. & Fujii, Mutue T., 2016, Chondrophycus anabeliae (Rhodomelaceae, Ceramiales), a new species in the Laurencia complex from the Mexican Caribbean, Phytotaxa 283 (3), pp. 259-270 : 261-262

Chondrophycus anabeliae Sentíes, M.T. Fujii, Cassano & Dreckmann sp. nov. ( Figs 1–18 ).

Type locality:— MEXICO, Quintana Roo, Isla Mujeres, Garrafón de Castilla ; 21° 12’ 32.28” N and 86° 43’ 17.83” W, coll. A. Sentíes, & M. C. Gil-Rodríguez s.n., tetrasporangial plant, 12 February 2007 (holotype UAMIZ 1240 ). Genbank accesion number for rbc L KX815262 . Paratype: ( UAMIZ 1241 ) vegetative and male plants, coll. A. Sentíes & M. T. Fujii s.n., 16 November 2008 .

Etymology:—The specific epithet makes reference to “Anabel”, the ancient goddess of love in the western Caribbean Sea region.

Diagnosis:—Plants forming tufts up to 7 cm high; thalli terete to partially compressed up to 1.5 mm in diameter, arising from a discoid holdfast; cartilaginous in texture; branching irregularly alternate and spirally arranged, usually with 2–3 (4) orders of branches; ultimate branchlets are cylindrical-clavate; two pericentral cells per vegetative axial segment, production of the first pericentral cell on the side of the trichoblast basal cell, trichoblast type spermatangial branches, procarp-bearing segment with five pericentral cells, tetrasporangia produced from a particular cell with the formation of one additional fertile pericentral cell, and arranged at a right-angle in relation to fertile branchlets.

Morphology: Plants forming tufts up to 7 cm high, terete to partially compressed axes ( Figs 1–4 ), cartilaginous in texture, not adhering to herbarium paper when dried. Thalli attached to the substratum by a discoid holdfast. Erect branches irregularly alternate and spirally arranged, usually with 2–3 (4) orders of branches. The main axes are partially compressed in the lower portions of the thalli, broader in the middle portions, 900–1,500 μm in diameter, and slightly narrowing towards the terete apices, 750–1,080 μm in diameter in the upper portions. Ultimate branchlets cylindrical to clavate and truncate at the apices, 800–2,950 μm long and 544–850 μm in diameter.

Vegetative structures: In surface view the outermost cortical cells are translucent, isodiametric-polygonal in the middle portions, 20–33 μm long and 10–20 μm wide, without secondary pit connections ( Fig. 5 ). Subcortical cells are pigmented, larger and connected to each other by secondary pit connections ( Fig. 6 ). In transverse section thalli formed by two cortical cell layers, and four or five layers of medullary cells ( Fig. 7 ). The translucent outer layer of cortical cells become evident, and they are smaller than the inner layer cells, measuring 20–25 μm long and 15–17.5 μm wide in the middle portions of main axes ( Fig. 8 ). These outer cortical cells are markedly projecting beyond the surface near the apices. The inner layer of cortical cells is composed of pigmented and elongated cells, measuring 50–52 μm long and 28–30 μm wide ( Fig. 8 ). Medullary cells are rounded or slightly radially elongated, measuring 75–115 μm long and 45–70 μm wide in the middle portions of the main axes. Medullary cell walls uniformly thickened, but lenticular wall thickenings are absent. Each vegetative axial segment cuts off two pericentral cells ( Figs. 9, 10 ) that are slightly smaller than the medullary cells of the surrounding layer.

Reproductive structures: Male branches are characteristically swollen, up to 800 μm in diameter ( Fig. 2 ). In longitudinal section through a fertile branchlet, the spermatangial pits are cup-shaped, and an axial cell row is discernible at the base ( Fig. 11 ). Spermatangial branches developed from two laterals on a suprabasal cell of trichoblast, terminating in a vesicular sterile cell, 37.5–40 μm long and 20–22.5 μm in diameter; partial sterility of the spermatangial branches was not seen. Spermatangia ovoid, 15–17.5 μm long and 5.0–7.5 μm in diameter with each spermatium possessing a noticeable apical nucleus ( Fig. 12 ).

In female thalli, each procarp-bearing segment producing five pericentral cells ( Fig. 13 ), the fifth of which becomes the supporting cell of a four-celled carpogonial branch with two groups of sterile cells ( Fig. 14 ). Fully developed cystocarps are conical, with a prominent ostiole, 500–750 μm in diameter, subapically arranged with the lower half immersed within the parent branch ( Figs. 3 , 15 ). Carposporangia are clavate, 80–200 μm long and 20–55 μm in diameter.

Tetrasporangial branchlets are cylindrical or slightly compressed, simple or compound, 800–1,200 μm long and 850–1,175 μm in diameter ( Fig. 4 ). Tetrasporangia are arranged in a right-angled pattern in relation to fertile branchlets ( Figs 4 , 16 ). At the apex of fertile branches, each axial segment produces one additional pericentral cell situated opposite to the existing two normal pericentral cells. The third additional cell becomes fertile, and the two pre-existing pericentral cells remain vegetative ( Fig. 17 ). The additional cell cuts off two pre-sporangial cover cells distally and abaxially positioned in relation to the tetrasporangial initial ( Fig. 18 ). Subsequently, one post-sporangial cover cell is produced and continues to divide, contributing to cortication around the tetrasporangia. The pre-sporangial cover cells do not divide and display a transverse-type alignment in relation to the fertile axis in surface view. Mature tetrasporangia are tetrahedrally divided, 30–130 μm in diameter ( Fig. 18 ).

Figures

FIGURES 1–4. Chondrophycus anabeliae sp.nov. (Holotype, UAMIZ 1240). Fig. 1. Habit (5 mm). Fig. 2. Female plant (1 mm). Fig. 3. Male plant (1 mm). Fig. 4. Tetrasporangial plant (1 mm).

FIGURES 5–8. Chondrophycus anabeliae sp.nov. Vegetative structures. Fig. 5. Surface view of translucent cortical cells (25 μm). Fig. 6. Surface view of subcortical cells. Note secondary pit connections between pigmented cortical cells (arrow) (25 μm). Fig. 7. Transverse section of the thallus (100 μm). Fig. 8. Detail of the two-layered cortical cells. Note small translucent outer cortical cells and large pigmented inner cortical cells with secondary pit connections between them (25 μm).

FIGURES 9–12. Chondrophycus anabeliae sp.nov. Vegetative and reproductive structures. Fig. 9. Transverse section of the upper portion of a branch showing two superimposed axial cells (a) each with two pericentral cells (p) (25 μm). Fig. 10. Transverse section showing two axial cells (a), each of which has two pericentral cells (p) and a basal trichoblast cell (bt) (25 μm). Fig. 11. Longitudinal section through a male branch with a cup-shaped spermatangial pit (50 μm). Fig. 12. Detail of trichoblast-type spermatangial branches with terminal vesicular sterile cells. Note spermatangia with an apical nucleus (arrow) (30 μm).

FIGURES 13–18. Chondrophycus anabeliae sp.nov. Reproductive structures.Fig. 13. Procarp-bearing segment with five pericentral cells, the fifth becoming the supporting cell (su) of the carpogonial branch; central cell of procarp-bearing segment (c) (10 μm). Fig. 14. Procarp before fertilization with four-celled carpogonial branch (cb), carpogonium (cg), trichogyne (tr), and supporting cell (su) (10 μm). Fig. 15. Longitudinal section through a female branchlet with partly immersed cystocarp and protuberant ostiole (100 μm). Fig. 16. Longitudinal section through a branchlet showing right-angle arrangement of the tetrasporangia (100 μm). Fig. 17. Transverse section of tetrasporangial axial segments showing an axial cell (a) and two vegetative pericentral cells (p) out of focus; an additional third fertile pericentral cell is formed in the opposite position (arrow) (25 μm). Fig. 18. Detail of a fertile pericentral cell (fp) with two pre-sporangial cover cells, one out of focus (pr), one post-porangial cell (po), and a tetrahedrically divided tetrasporangium (te). Note cortical cells markedly projected.