Sirodotia amazonica Necchi, N. L. Rossignolo & M. O. Paiano 2021, sp. nov.
Creators: name: Rossignolo, Natalia L.
name: Vis, Morgan L.
name: Paiano, Monica O.
name: Eloranta, Pertti
name: West, John A.
name: Ganesan, E. K.
name: Yasmin, Farishta
name: Lim, Phaik-Eem
name: Necchi, Orlando Jr
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Rhodophyta
Florideophyceae
Nemaliales
Batrachospermaceae
Sirodotia
Sirodotia amazonica

description: Sirodotia amazonica Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov.
(Fig. 3 A-E)
TYPE. — O. Necchi Jr., 27.IX.2010, (holo-, SJRP [SJRP 31924]).
TYPE LOCALITY. — Brazil, Mato Grosso, River Rosana, Route BR- 163, between Sinop and Sorriso; 11°57’26”S, 55°31’01”W.
ADDITIONAL SPECIMENS EXAMINED. — SJRP 32139, SJRP 32140, SJRP 32576, SJRP 32577, and SJRP 32578 (Appendix 1).
ETYMOLOGY. — The species epithet indicates that the alga occurs in the Amazonian region in Brazil.
DISTRIBUTION. — South America: Brazil (mid-western and northern Brazil).
REPRESENTATIVE DNA SEQUENCES. — COI-5P (KF010489, KF010490, MW053464), rbc L (KC951866, KC951867, MW053480) and LSU (BR14, BR15, MW053499).
Description
Plants monoecious or dioecious; whorls 249-491 µm in diameter; primary fascicles, 4-8 cells; proximal cells cylindrical or ellipsoidal; distal cells spherical, subspherical, obovoidal or ellipsoidal; secondary fascicles abundant, covering the entire internode; spermatangia spherical or obovoidal, 1-3 in a group, few or abundant on primary or secondary fascicles, 6-9 µm in diameter; carpogonial branches composed of 1-4 disc- or barrel shaped cells, arising from periaxial or proximal cells of primary fascicles, rarely on the secondary fascicles or cortical filaments, short, 8.5-25 µm in length; carpogonia with sessile, elongate cylindrical (with wave margins) or fusiform trichogynes, 35-58(-62) µm in length, 8-14(-15) µm in diameter; gonimoblast initial developing from the protuberant side of the carpogonium; gonimoblast filaments prostrate with erect branches of 1-4 cells; carposporangia obovoidal or subspherical, 10-18(-19) µm in length, (7-)8-13 µm in diameter.
Remarks
The phylogeography study by Paiano & Necchi (2013) showed the existence of two cryptic species in Brazil. No morphological characteristics were observed to distinguish them, but a high interspecific divergence (2.3-3.0% for rbc L and 4.4-6.2% COI-5P). We conclude they are distinct. Sirodotia amazonica Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov. is very similar to two species found in Brazil, S. delicatuliformis Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov. and S. cryptica Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov., overlapping for most morphometric and morphological characters. However, S. amazonica Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov. is distinguishable from S. delicatuliformis sp. nov. based on the wider carposporangia (8-13 versus 6-8.5(-9.5) µm in diameter).
description: Published as part of Rossignolo, Natalia L., Vis, Morgan L., Paiano, Monica O., Eloranta, Pertti, West, John A., Ganesan, E. K., Yasmin, Farishta, Lim, Phaik-Eem & Necchi, Orlando Jr, 2021, Revision of the genus Sirodotia Kylin (Batrachospermales, Rhodophyta) with description of four new species, pp. 93-127 in Cryptogamie, Algologie 20 (8) on page 101, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571