Sirodotia delicatuliformis Necchi, N.L.Rossignolo & M.O.Paiano, 2021

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, Cryptogamie, Algologie 20 (8), pp. 93-127 : 106-108

Sirodotia delicatuliformis Necchi, N.L.Rossignolo & M.O.Paiano , sp. nov.

( Fig. 5 F-L)

TYPE. — O. Necchi Jr., 25.VI.2008, (holo-, SJRP [ SJRP 31918 ].

TYPE LOCALITY. — Brazil, São Paulo State, Mirassol, São José dos Dourados River; 20°48’45”S, 49°34’29”W.

DISTRIBUTION. — South America: Brazil (southeastern) and Central America: Costa Rica.

REPRESENTATIVE DNA SEQUENCES. — COI-5P ( KF010483 , KF010486 e KF010487 ), rbc L ( KC951857 , KC951858 , KC951863 ) and LSU ( MW053486 , MW053487 , MW053491 ).

ADDITIONAL SPECIMENS EXAMINED. — SJRP 23450, SJRP 23501, SJRP 31915, SJRP 31916, SJRP 31917, SJRP 31919, SJRP 31920, SJRP 31921, SJRP 31922, SJRP 32156, SJRP 32579 and SJRP 32580 ( Appendix 1).

ETYMOLOGY. — The species epithet indicates that the alga is morphologically very similar to S. delicatula .

Description

Plants monoecious, dioecious or polyoecious; whorls 169- 491 µm in diameter; primary fascicles 5-10(-13) cells; proximal cells cylindrical, ellipsoidal or obovoidal; distal cells obovoidal, ellipsoidal or spherical; secondary fascicles abundant, covering the entire internode; spermatangia spherical or obovoidal, single or in pairs on primary or secondary fascicles, 5-8(-8.5) µm in diameter; carpogonial branches composed of 0-4 disc- or barrel shaped cells, arising from periaxial, proximal or distal cells of primary fascicles, rarely on secondary fascicles or cortical filaments, short, 6-22 µm in length; carpogonia with sessile, elongate cylindrical (with wavy margins) or fusiform trichogynes, sometimes with anomalous shapes (bifurcated or with bent end), (20-)22- 55(-59) µm in length, 8-14(-16) µm in diameter; gonimoblast initial developing from the protuberant side of the carpogonium; gonimoblast filaments with erect branches of 1-4 cells; carposporangia obovoidal or ellipsoidal, 11-16 µm in length, 6-8.5(-9.5) µm in diameter.

Remarks

This species has been previously reported as S. delicatula ( Necchi 1991; Necchi et. al 1993; 2007) from South and North America. Based on recent studies including molecular data ( Paiano & Necchi 2013; Johnston et al. 2014; this study), the sequences from South and North America were showed to be genetically divergent from the sequence of S. delicatula from Malaysia.Thus, it represents a distinct species that is here described. The species is highly divergent in sequence from S. delicatula . However, these two species are morphologically very similar with considerable overlap for all morphological characters, but the disjunct geographic distribution that can be applied as criterion to distinguish them. In addition, this species formed a lineage with three other species ( S. amazonica Necchi, N.L.Rossignolo & M.O.Paiano , sp. nov., S. cryptica Necchi, N.L.Rossignolo & M.O.Paiano , sp. nov. and S. aquiloamericana ) from North and South America. The morphology among these species is similar, but S. delicatuliformis Necchi, N.L.Rossignolo & M.O.Paiano , sp. nov. is distinguishable from S. amazonica and S. cryptica based on the narrow carposporangia (6-8.5(-9.5) versus 8-13 µm in diameter), and from S. aquiloamericana by having smaller whorls (169-491 versus 408-675 µm in diameter).

Sirodotia huillensis (Welwitsch ex West & G.S.West) Skuja

( Fig. 6 A-E)

Archiv für Protistenkunde 74: 304 ( Skuja 1931). — Batrachospermum huillense Welwitsch ex West & G.S.West , Journal of Botany 35: 3 (West & West 1897).

TYPE. — F. M. J. Welwitsch, V.1860 (holo-, BM[BM 001043858]; iso-, LISU).

TYPE LOCALITY. — Africa, Angola, Huila, Lopollo, 14°47’51”S, 14°40’03”E.

ADDITIONAL SPECIMEN EXAMINED. — BHO A-1447 ( Appendix 1).

DISTRIBUTION. — Africa: Angola, Madagascar, Reunion, South Africa.

R EPRESENTATIVE DNA SEQUENCES. — COI-5P ( MN974523 ) and rbc L ( JF344717 ).

Revised description

Plants monoecious or dioecious; whorls 162-364 µm in diameter; primary fascicles (5-)6-10 cells; proximal cells cylindrical, ellipsoidal or obovoidal; distal cells subspherical, obovoidal or ellipsoidal; secondary fascicles abundant, covering the entire internode; spermatangia spherical, 1-3, few or abundant on primary fascicles, 5-7 µm in diameter; carpogonial branches composed of 1-3 disc- or barrel shaped cells, arising from periaxial or distal cells of primary fascicles, short, 5-14 µm in length; carpogonia with sessile, elongate cylindrical (with wavy margins), ellipsoidal, fusiform or lageniform trichogynes, 28.5-48 µm in length, 5.5-12 µm in diameter; gonimoblast initial developing from the protuberant side of the carpogonium; gonimoblast filaments with erect branches of 2-4 cells; carposporangia obovoidal, 8-10 µm in length, 5-8 µm in diameter.

Remarks

This species is most closely comparable to S. kennedyi based on the reduced whorls (162-364 µm in diameter), shorter carposporangia (8-10 um in length) and geographic distribution (occurrence in Africa). However, S. huillensis differs from S. kennedyi in having a greater number of cells in primary fascicle (5-9(-10) versus 3-5), a small number of cells in the carpogonial branches (1-3 versus 3-4), a shorter carpogonial branch (5-14 versus 16-22 µm in length) and a greater number of cells in the erect gonimoblast filament (2-4 versus 1-2, Appendices 4-6). In addition, they are genetically divergent. In the description of this species from Africa ( Madagascar and Reunion) bySkuja (1931) and then later by Necchi et al. (1993) in specimens from North America (Arizona and Texas), this species was reported to have spermatangia arranged in clusters. However, this type of arrangement, characterized by the terminal and subterminal cells bearing two to four spermatangia, was not confirmed in the type or protologue. That arrangement of spermatangia in clusters was observed only in S. assamica , whereas in some populations of S. huillensis only abundant and densely arranged spermatangia were found. The species referred by Lam et al. (2012) as S. aff. huillensis (BHO A-1447), which was analyzed in this study, could not be conclusively identified based on morphology for the limited morphological characters provided or examined. Phylogenetic analyses based on molecular data ( Lam et al. 2012; this study) of the specimen referred to as S. aff. huillensis collected in South Africa was genetically distinct from specimens described as S. huillensis from North America. Therefore, the specimen, S. aff. huillensis , collected closer to type locality of S. huillensis , is interpreted as S. huillensis and the North American specimens represent another species ( S. aquiloamericana ).

Figures

FIG. 5. – Morphological features of Sirodotia species: A-E, Sirodotia delicatula Skuja (photos taken from sample BHO A-0984): A, obconical whorls; B, primary fascicle; C, carpogonium with a mature trichogyne (arrow) showing the basal hemispherical protuberance (arrowhead); D, fertilized carpogonium with a sessile cylindrical trichogyne, attached spermatium (arrowhead) and gonimoblast initial developing from the protuberant side of the carpogonial base (arrow); E, carposporangia (arrow) and erect gonimoblast filaments (arrowhead); F-L, Sirodotia delicatuliformis Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov. (photos taken from sample SJRP 31918 – holotype): F, obconical whorls; G, primary fascicle; H, primary fascicle with spermatangia (arrow) and anomalous shape (bent end) trichogyne (arrowhead); I, carpogonium with a mature trichogyne (arrow) showing the basal hemispherical protuberance (double arrow); J, carpogonium with anomalous shape (bifurcate) trichogyne (arrow); K, carpogonium with a sessile cylindrical trichogyne (short arrow), attached spermatium (long arrow) and gonimoblast initial developing from the protuberant side of the carpogonial base (double arrow); L, carposporangia (long arrow) and erect (short arrow) gonimoblast filaments.Scale bars: A, F, 200 μm; B, C, D, E, I, 20 μm; D, K, 10 μm G, H, 50 μm; L, 25 μm. D, redrawn from Johnston et al. (2014); K, redrawn from Necchi (1991).

FIG. 6. — Morphological features of Sirodotia species: A-E. Sirodotia huillensis (Welwitsch ex West & G.S.West) Skuja (photos taken from sample BHO A-1447): A, obconical whorls; B, C, primary fascicles with spermatangia (arrows); D, E, carpogonia with irregular trichogyne (arrowheads) showing the basal hemispherical protuberance (double arrows) and gonimoblast initial developing from the protuberant side of the carpogonium (arrow); F, carposporangia (arrows) and erect gonimoblast filaments (arrowheads). G-I, Sirodotia kennedyi (photos taken from sample BHO A-0946): G, obconical whorls; H, primary fascicles (arrows) and carpogonium with irregular trichogyne (arowhead) and basal hemispherical protuberance (double arrowhead); I, carposporangia (arrow), prostrate (arrowhead) and erect (double arrowhead) gonimoblast filaments. J-N, Sirodotia suecica Kylin (photos taken from samples BHO A-0266, SJRP32582, SJRP32583): J, obconical whorls; K, primary fascicles with terminal spermatangia (arrows); L, carpogonia with mature trichogyne (arrows) and basal hemispherical protuberance (arrowhead); M, fertilized carpogonium with attached spermatium (arrow) and gonimoblast initial (double arrowhead) on the opposite side of the basal protuberance (arrowhead); N, carposporangia (arrows), prostrate (arrowhead) and erect (double arrowhead) gonimoblast filaments. Scale bars: A, G, J, 100 μm; B-C, H-I; D-F, L-M, 10 μm; K, 50 µm. B-F, redrawn from Skuja (1931); H-I, modified from Szinte et al. (2020); M, redrawn from Necchi et al. (1993).