Sirodotia assamica Necchi, N.L.Rossignolo, F.Yasmin, J.A.West & Ganesan

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 : 102

Sirodotia assamica Necchi, N.L.Rossignolo, F.Yasmin, J.A.West & Ganesan

( Fig. 4 A-E)

Phytotaxa 437: 125 (2020).

TYPE. — F. Yasmin, 25.II.2019 (holo-, SJRP [ SJRP 32584]).

TYPE LOCALITY. — India, Assam, Nagaon District, Chapanalla; 26°19’13.7”N, 92°10’16.5”E.

ADDITIONAL SPECIMENS EXAMINED. — SJRP 32583, SJRP 32585 ( Appendix 1).

DISTRIBUTION. — Asia, India (northeastern).

REPRESENTATIVE DNA SEQUENCES. — COI-5P ( MN508239 , MN508240 ) and rbc L ( MN496129 , MN496130 ).

Description

Plants dioecious or monoecious; whorls 400-665 µm in diameter; primary fascicles, 6-11(-12) cells; proximal cells cylindrical or ellipsoidal; distal cells obovoidal or ellipsoidal; secondary fascicles abundant, covering the entire internode; spermatangia spherical, arranged in clusters on primary or secondary fascicles, 6-8 µm in diameter; carpogonial branches straight or slightly curved, short, composed of 1-5(-6) discor barrel shaped cells; arising from periaxial cells of primary fascicles, 7-23 µm in length; carpogonia with sessile, elongate cylindrical, ellipsoidal or lageniform trichogynes, 37-64 µm in length, 10-14(-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, 11-14 µm in length, 6-8 µm in diameter.

Remarks

A distinguishing feature of Sirodotia assamica is the occurrence of spermatangia arranged in clusters, thus far not confirmed for any other species of Sirodotia . It is most closely comparable to S. delicatula based on other vegetative and reproductive characteristics and its occurrence in or near India ( Appendix 6). Sirodotia assamica differs from S. delicatula in having spermatangia in clusters, larger whorls (400-665 µm versus 137-433 µm in diameter), distal fascicles cells ellipsoidal or obovoid (L/D 1.3-2.1) in S. assamica and subspherical or obovoid (L/D 1.1-1.7) in S. delicatula and the known geographic distribution restricted to northeastern India.

Figures

FIG. 4. – Morphological features of Sirodotia species.A-E, Sirodotia assamica Necchi,Rossignolo,Yasmin,J.A.West & Ganesan (photos taken from samples SJRP 32583,32584):A, B; primary fascicles with spermatangia in clusters (arrows); C, a carpogonium with a mature trichogyne (arrow) showing the basal hemispherical protuberance (arrowhead); D, fertilized carpogonium with attached spermatium (arrow), gonimoblast initial (arrowhead) developing from the same side of the basal protuberance (arrowhead); E, carposporangia (arrow), prostrate (arrowhead) and erect (double arrowhead) gonimoblast filaments; F-J, Sirodotia cryptica Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov. (photos taken from sample SJRP 32575 - holotype): F, obconical whorls; G, primary fascicle with spermatangia (arrow); H, carpogonium with a mature cylindrical trichogyne (arrow) showing the basal hemispherical protuberance (arrowhead); I, fertilized carpogonium with a sessile elongate-conical trichogyne (arrowhead), attached spermatium (arrow) and gonimoblast initial developing from the protuberant side of the carpogonial base (double arrowhead); J, carposporangia (arrows) and erect gonimoblast filaments (arrowheads). Scale bars: A, B, G, 50 μm; C, D, H-J, 20 μm; E 10 μm; F, 200 μm. B-D, reproduced with permission from Rossignolo et al. (2020) (Magnolia Press).