Gracilaria falconii Ardito, Núñez-Resendiz, Dreckmann & Sentíes, 2017

Ardito, Sonia, Núñez-Resendiz, María Luisa, Dreckmann, Kurt M. & Sentíes, Abel, 2017, Gracilaria falconii sp. nov. (Gracilariales, Rhodophyta): a new species with flat axes from Venezuela, Phytotaxa 292 (3), pp. 271-278 : 272

Gracilaria falconii Ardito, Núñez-Resendiz, Dreckmann & Sentíes sp. nov. ( Figs. 1–8 )

Type: VENEZUELA. Falcón: Chichiriviche ; 10°55’45” N 68°16’07” W, 19 May 2015, coll. S. Ardito, A. Sentíes, M. Toyota & V. Cassano 3017 (holotype VEN 438409 , vegetative, Fig. 1 ) GenBank accession number for rbc L KX427105 .

Isotypes: VENEZUELA. Falcón: Chichiriviche ; 10°55’45” N 68°16’07” W, 19 May 2015, coll. S. Ardito, A. Sentíes, M. Toyota & V. Cassano 3018 (isotype UAMIZ 1243 , vegetative, Fig. 2 ) and Ibid.3019 (isotype LUC 1646 ,vegetative) GenBank accession numbers for rbc L KX427104 and KX427106 .

Diagnosis: Thallus flattened, axes 3 to 7 mm in width, branching dichotomous to irregular, sharp transition between cortex and medulla. Cortex of one to two layers of pigmented, anticlinally elongated cells, 2.5–5 μm by 7.5–12.5 μm. Medullary region composed of five layers of cells, those near the cortex 35–80 μm by 28–90 μm, subspherical, those of the center 170–320 μm by 100–250 μm, elongated.

Habitat: Growing on wood in the subtidal up to 0.50–1.50 cm depth, on calm waters.

Etymology: Gracilaria falconii ; the specific epithet makes reference to Falcón State, Venezuela.

Description: Thallus erect, dark violet to purple red in color, 2 to 3.5 cm high, one to three main axes, flattened, branching dichotomous to irregular in one plane. Branches 3 to 7 mm in width, narrower than the main axis, tapering towards the base without being totally constricted, apices rounded, very rarely acute, occasionally bifurcate. Margins entire. Stipe short and complanate in cross-section. Sharp transition between cortex and medulla. Cortex of one to two layers of pigmented, anticlinally elongated cells, 2.5–5 μm by 7.5–12.5 μm. Medullary region composed of five layers of cells, those near the cortex 35–80 μm by 28–90 μm, subspherical, those of the center 170–320 μm by 100–250 μm, elongated. Reproductive structures not seen.

Figures

FIGURES 1–8. Gracilaria falconii sp. nov. Fig 1. VEN 438409, holotype, vegetative specimen, scale bar: 4 mm Fig. 2. UAMIZ-1243, isotype, vegetative specimen, scale bar: 4 mm. Fig. 3. Base of the branch, scale bar: 500 μm. Figs. 4–6. Variation at the apical form, scale bar: 200 μm. Fig. 7. Transverse section of the vegetative thallus, showing sharp transition between and cortex and medulla, scale bar: 30 μm. Fig. 8. Transverse section of the vegetative thallus, showing forms of cortical and medullary cells, scale bar: 10 μm.