Sirodotia delicatula Skuja

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 : 104

Sirodotia delicatula Skuja

( Fig. 5 A-E)

Archiv für Hydrobiologie Supplement 15: 614 (Skuja 1938). — Batrachospermum delicatulum (Skuja) Necchi & Entwisle, Phycologia 29: 486 (1990).

Sirodotia ateleia Skuja, Archiv für Hydrobiologie Supplement 15: 617 (1938).

TYPE. — D. L. Sunda-Expedition, 19.IX.1928 (lecto-, UPS [ UPS A-003747]).

TYPE LOCALITY. — Indonesia, Java Island, Bogor, Tijiliwong; 6°35’21”S, 106°48’19”E.

ADDITIONAL SPECIMENS EXAMINED. — BHO A-0984 ( Appendix 1).

DISTRIBUTION. — Asia: Indonesia, Japan and Malaysia.

REPRESENTATIVE DNA SEQUENCES. — COI-5P ( MW176122 ), rbc L ( KF557560 ) and LSU ( MW053507 ).

Revised description

Plants monoecious or dioecious; whorls 137-484 µm in diameter; primary fascicles, 5-10 cells; proximal cells cylindrical or ellipsoidal; distal cells subspherical or obovoidal; secondary fascicles abundant, covering the entire internode; spermatangia spherical or obovoidal, 1-3, few or abundant on primary fascicles, (4-)7-8 µm in diameter; carpogonial branches composed of 2-5(-7) disc- or barrel shaped cells, arising from the periaxial or middle cells of the primary fascicles, short, 8-17(-20) µm in length; carpogonia with sessile, elongate cylindrical (with wavy margins), fusiform, ellipsoidal or clavate trichogynes, (19-)24-70 µm in length, 5-13 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-)10-16 µm in length, 5-10 µm in diameter.

Remarks

This species is morphologically similar to four species of Sirodotia ( S. delicatuliformis Necchi, N.L.Rossignolo & M.O.Paiano , sp. nov., 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 ). Like these species, it has large carposporangia, spermatangia single or in pairs on primary fascicles and gonimoblast initial developing from the protuberant side of carpogonium. It is distinguishable from those species only in its geographic distribution (restricted to Asia versus Americas). Sirodotia delicatula has been recorded from Indonesia and Japan and more recently reported from Malaysia including rbc L sequences ( Johnston et al. 2014). It had been previously reported in South America ( Brazil) ( Necchi 1991; Necchi et al. 1993, 2007; Paiano & Necchi 2013). However, Asian specimens are distinguishable from South American ones based on the divergences in the DNA sequences and in the known geographic distribution (Asia versus South America). Since Malaysia is closer to the type locality, the Asian specimens are regarded as representing the species. Sirodotia ateleia Skuja was considered a synonym of S. delicatula by Umezaki (1960) and Necchi (1991) based on a combination of morphological characters. On the other hand, based on the examination of North America populations identified as S. huillensis and the type of S. ateleia, Necchi et al. (1993) considered these two taxa to be synonymous by the size and shape of the whorls. In this study we followed the proposal by Umezaki (1960) and Necchi (1991) of S. ateleia being synonymous with S. delicatula based on similarity of morphological characters and geographic distribution in Asia, although S. ateleia has longer carpogonia (42-70 µm versus (19-)24-57 µm in length).

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).