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Surveys of Hawaiian macroalgae over the past 15 years have yielded numerous specimens representing species new to science. Calliblepharis yasutakei sp. nov. is here described based on a plant collected at a depth of 98 m from Kapou, Papahânaumokuâkea Marine National Monument, Hawaiʻi. Phylogenetic analyses of three molecular markers (COI, rbcL, and SSU) and analyses of morphological features were used to describe the new species in the family Cystocloniaceae. Calliblepharis yasutakei sp. nov. grouped with C. fimbriata, C. rammediorum, C. occidentalis and C. jolyi in a clade with full support for the rbcL analysis, representing a distinct lineage within the genus. Phylogenetic and vegetative morphological comparisons demonstrated that the new Hawaiian species is most closely related to C. rammediorum from Israel (rbcL similarity of 96.3%), although no female reproductive structures were found to allow a more comprehensive comparison. In order to determine whether C. yasutakei represents the first confirmed report of the genus Calliblepharis in the Hawaiian Islands, phylogenetic and morphological analysis of the Hawaiian Hypnea saidana (=Calliblepharis saidana) specimen accessioned at the Bernice P. Bishop Museum was performed. These analyses demonstrated that this specimen belongs to a new species in the genus Hypnea, which is here described as H. tsudae sp. nov. C. yasutakei, in addition to being a new species, is also reported as the first confirmed record of the genus Calliblepharis in the Hawaiian archipelago, and the description of H. tsudae brings the number of species for this genus in Hawaiʻi to eight.

Calliblepharis yasutakei M.O.Paiano & A.R.Sherwood, sp. nov. (Fig. 3 A-H) Holotype: — U.S.A. Hawai‘i, Papahânaumokuâkea Marine National Monument, Kapou (Lisianski), 26.08363°N, 174.16647°W, 98 m depth, 30 July 2019, R. Kosaki (holotype BISH 783229; ARS 10483; field code NWHI-761). Description: Thallus erect, delicate, pinkish-red when living, drying to dark red along the main axis and pink along some branches, slightly compressed, plant 3.8 cm tall × 2.6 cm wide (Fig. 3A–B), attached to the substratum by a small and inconspicuous holdfast. Thallus irregularly or dichotomously branched, at narrow angles, with branches up to 3.1 mm wide (Fig. 3B). Upper part of thallus sparsely branched; lacking anastomoses. Thallus organization uniaxial, apex consisting of a single apical cell (Fig. 3C). Surface view of cortical cells irregular to polygonal, 10–20 µm × 5–15 µm, with rosette cells weakly developed around the cortical cells (Fig. 3D). Pit-connections absent. Lenticular thickenings frequently observed in cortical cells (Fig. 3E–F). Cross sections 250–295 μm thick, with medulla consisting of one layer of large, rounded cells, 66.7–74.1 μm long, 85.2–92.6 μm wide, and one outer layer of pigmented, rounded to irregular small cells, 11.1–22.1 μm long, 7.4–22.2 μm wide (Fig. 3G). Central axial filament evident in surface view, consisting of elongate cells (arrows), 20–40 μm long × 8–15 μm wide, surrounded by 2–3 layers of medullary cells and one or two layers of rounded cortical cells. (Fig. 3H). Unicellular hairs not observed. Reproductive characters were not observed. Etymology:— C. yasutakei is named in memory of Mr. Yumi Yasutake, a long-time educator and scientist for the Papahânaumokuâkea Marine National Monument. Through the use of algal pressings as a student activity, Yasutake shared his love of phycology, marine science, and Papahânaumokuâkea with legions of young people throughout the state of Hawai‘i. Distribution and Habitat:— Known only from the type locality, at 98 m depth. Identification using DNA sequence data:— GenBank accessions OL795915 (COI), OL795916 (rbc L) and OL828740 (SSU)., Published as part of Paiano, Monica O., Fumo, James T., Cabrera, Feresa P., Kosaki, Randall K., Spalding, Heather L. & Sherwood, Alison R., 2022, Calliblepharis yasutakei sp. nov. and Hypnea tsudae sp. nov. (Cystocloniaceae, Rhodophyta): novel diversity from the Hawaiian Islands, pp. 74-86 in Phytotaxa 572 (1) on pages 79-80, DOI: 10.11646/phytotaxa.572.1.5, http://zenodo.org/record/7305722

Hypnea tsudae M.O.Paiano F.P.Cabrera & A.R.Sherwood, sp. nov. (Fig. 4 A-H) Holotype: — U.S.A. Hawai‘i, Pu‘ukohala Heiau National Park, Island of Hawai‘i 20.748°N, 24.384°W, 1.5 m depth, 03 August 2006, C. Squair (holotype BISH 740394). Paratypes: — ARS 03115 (BISH 786150) from U.S.A. Hawai‘i, Island of Maui, Hana, Kaihalulu Beach, 20.7589°N, 155.985°W, intertidal, 10 December 2007, K. Conklin; ARS 03542 (BISH 786151) from U.S.A. Hawai‘i, Island of Kauai, 22.2208°N, 159.583°W, intertidal, 17 March 2007, A. Kurihara. Description: Thalli upright, terete, ranging from 1.2–4.5 cm in length (Figs 4A–C), usually rich red in color when living, drying to a light pink to orange when pressed (Fig 4A). Thalli are compressed with thorn-like branchlets that are often dichotomously branched at the apices and alternately branched in the mid to basal portions (Figs 4D–E). Branching most often in three-dimensional space (Figs 4A–E). In surface view, thallus is composed of small cortical cells, elongated, 4.0–7.5 μm in length and 2.0–10.8 μm in diameter (Fig 4F). Axes uniaxial, rounded. Transverse sections 310–440 μm in diameter (Figs 4G–H). Each axial cell surrounded by three to five periaxial cells (Figs 4G–H), 38–45 μm in diameter, surrounded by two to four layers of large, rounded to cuboidal medullary cells, 30–98 μm in length and 20–60 μm in width. Holdfast not observed. Only sterile plants observed. Etymology:— This species is named in memory of our colleague, Dr. Roy Tsuda, who made many contributions to our understanding of the flora of the Western Pacific, and who collaborated with us extensively on the taxonomy of the mesophotic flora of the Hawaiian Islands and the Papahânaumokuâkea Marine National Monument. Distribution and Habitat:— subtidal from Island of Hawai‘i, intertidal coastal waters of Maui and Kaua‘i, in the Main Hawaiian Islands, USA. Identification using DNA sequence data:— GenBank accessions OL 795917 (COI), OL 795918 (rbc L) and OL 828741 (SSU) for the holotype, ON 704651 (ARS 03115) and ON 704652 (ARS 03542) (rbc L) for the paratypes., Published as part of Paiano, Monica O., Fumo, James T., Cabrera, Feresa P., Kosaki, Randall K., Spalding, Heather L. & Sherwood, Alison R., 2022, Calliblepharis yasutakei sp. nov. and Hypnea tsudae sp. nov. (Cystocloniaceae, Rhodophyta): novel diversity from the Hawaiian Islands, pp. 74-86 in Phytotaxa 572 (1) on page 82, DOI: 10.11646/phytotaxa.572.1.5, http://zenodo.org/record/7305722

Incendia lisianskiensis A.R. Sherwood sp. nov. (Fig. 1A���J) Type: ��� USA. Hawai���i, Papahānaumokuākea Marine National Monument, Kapou (Lisianski Island), 26.025277��N, 174.15694��W, 55 m depth, 30 July 2019, B. Hauk (holotype BISH 780872; ARS 09969; field code NWHI-846). Description: Thallus crustose, prostrate, on coral rubble, reddish in color with orange markings (Fig. 1A). Thallus moderately calcified, with undulating margins, and raised ridges on the thallus surface Fig. 1A). Hypothallus filaments consisting of mostly unbranched, parallel files of rectangular cells, cells 5.0���7.0 ��m in width �� 16.3���19.0 ��m in height, giving rise to perithallial assurgent filaments above and rhizoids below (Fig. 1B���E). Crusts thin, ranging from 120���190 ��m. Perithallial assurgent filaments arising at more or less 90�� angle from hypothallus (Fig. 1B���D). Cells of mid- to lower perithallus irregularly subisodiametric, 5.1���9.2 ��m in width �� 7.5���11.4 ��m in height (Fig. 1B���D). Lower perithallial cells forming cellular projections and secondary pit connections (Fig. 1B���D). Upper perithallial cells smaller than those in the lower perithallus, isodiametric to slightly taller than broad; 3.4���7.2 ��m width �� 6.7���8.2 ��m height (Fig. 1B,C). Rhizoids 4.8���10.0 ��m diameter, medium to long, unbranched, and multicellular (Fig. 1F). Hair cells absent (Fig. 1G). Gametangial and tetrasporangial reproduction not observed. Distribution and Habitat:��� Known only from the type locality. Etymology:��� Named for the type locality. Identification using DNA sequence data:��� Neighbor-joining analysis of available COI sequences for currently recognized species of Incendia and Seiria (and other non- Peyssonnelia species in the Peyssonneliales) supported the recognition of I. lisianskiensis as a novel species (Fig. 2). The Incendia lisianskiensis COI sequence (MZ043101) differed by 7.4% (p-distance) from its most similar congener with COI representation, I. regularis K.R.Dixon, and by>9.0% from all other available Incendia COI sequences. The rbcL phylogeny (ML topology is shown, with support values from both analyses included at nodes) also indicated a close relationship between I. lisianskiensis and I. regularis, supporting the inclusion of this specimen in the genus Incendia, and the distinction of I. lisianskiensis from other Incendia taxa included in the analysis (Fig. 3)., Published as part of Sherwood, Alison R., Cabrera, Feresa P., Spalding, Heather L., Alvarado, Erika A., Smith, Celia M., Hauk, Brian B., Matadobra, Stephen J., Kosaki, Randall K. & Paiano, Monica O., 2021, Biodiversity of Hawaiian Peyssonneliales (Peyssonneliaceae, Rhodophyta): new species in the genera Incendia and Seiria, pp. 14-26 in Phytotaxa 524 (1) on page 19, DOI: 10.11646/phytotaxa.524.1.2, http://zenodo.org/record/5606530

Seiria mesophotica A.R. Sherwood sp. nov. (Fig. 4A���J) Type: ��� USA, Hawai���i, off West Moloka���i, 21.0455��N, 157.3524��W, 80 m depth, 28 November 2006, H. Spalding (holotype BISH 780873; ARS 09666; field code P4-189 -cont.8-#328). Description: Thallus crustose, prostrate, on coral rubble, brick red to dark, brownish maroon in color (Fig. 4A,B). Thallus moderately to heavily calcified, somewhat lobed or entire, mostly to completely adherent to substratum. Crusts thin, typically approximately 100 ��m, ranging from 80���180 ��m (Fig. 4C���E). Hypothallus filaments consisting of parallel files of cells (Fig. 4G), mostly unbranched, cells 4.6���8.8 ��m in width and 18.2���27.7 ��m in height, giving rise to perithallial assurgent filaments above and rhizoids below. Perithallial assurgent filaments arising at 60���90�� angle from hypothallus (Fig. 4C���E). Perithallus thin, composed of short filaments that are mostly 4���8 cells long (Fig. 4C���E). Lower perithallial cells taller than broad, 14.5���24.8 ��m in height �� 5.9���8.0 ��m in width (Fig. 4D). Perithallial cells becoming shorter towards upper portion of perithallus. Mid-perithallial fusion cells absent. Uppermost perithallial cells quasi-isodiametric, 7.8���15.8 ��m width �� 5.0���9.3 ��m height (Fig. 4E). Cuticle on surface of perithallus 4���8 ��m thick (Fig. 4C���E). Rhizoids 5.4���8.8 ��m diameter, mostly short to medium length, unbranched, and unicellular (Fig. 4F). Hair cells absent (Fig. 4H). Gametangial reproduction not observed. Mature tetrasporangia 43���99 �� 22���44 ��m, cruciate decussate to irregularly cruciate (Fig. 4I), borne in raised, subcircular, scattered gelatinous nemathecia, nemathecial paraphyses up to 9 cells in length, 130 ��m long (Fig. 4J). Other examined material:��� USA, Hawai���i: Papahānaumokuākea Marine National Monument, Manawai (Pearl and Hermes Atoll), 27.9625��N, 175.8361��W, 67 m depth, 31 July 2019, S. Matadobra (BISH 780874; ARS 09967; field code NWHI-833). Distribution and Habitat:��� Known from the off West Moloka���i in the Main Hawaiian Islands and Manawai of the Papahānaumokuākea Marine National Monument at mesophotic depths of 67- 80 m. Etymology:��� Named for the mesophotic depths at which the specimens were collected. Identification using DNA sequence data:��� A DNA barcoding analysis of COI sequences for the two specimens of Hawaiian Seiria (MZ043099 and MZ043100) and available COI data for related taxa demonstrated less than 4% sequence divergence between the two Hawaiian specimens (3.3% difference between ARS 09666 and ARS 09967), and much greater distance to the type species, S. magnifusa K.R.Dixon (12.0-12.2%; Fig. 2). The rbcL phylogeny supported S. magnifusa as the closest relative to S. mesophotica, with 12.1-13.0% difference in the sequences of the two taxa (Fig. 3)., Published as part of Sherwood, Alison R., Cabrera, Feresa P., Spalding, Heather L., Alvarado, Erika A., Smith, Celia M., Hauk, Brian B., Matadobra, Stephen J., Kosaki, Randall K. & Paiano, Monica O., 2021, Biodiversity of Hawaiian Peyssonneliales (Peyssonneliaceae, Rhodophyta): new species in the genera Incendia and Seiria, pp. 14-26 in Phytotaxa 524 (1) on pages 20-24, DOI: 10.11646/phytotaxa.524.1.2, http://zenodo.org/record/5606530

Sirodotia aquiloamericana Necchi, N.L.Rossignolo & M.L.Vis, sp. nov. (Fig. 3 F-J) TYPE. — T.A. Dempster, 24.IV.2011 (holo-, BHO [BHO-0437]). TYPE LOCALITY. — United States, Arizona, outlet canal of Montezuma; 34°38’57”N, 111°45’08”W. ADDITIONAL SPECIMENS EXAMINED. — BHO A-0410, MEX 1. ETYMOLOGY. — The species epithet indicates that the alga is known from North America. DISTRIBUTION. — North America: Mexico and the United States (Arizona and Texas). REPRESENTATIVE DNA SEQUENCES. — COI-5P (MW053469, MW053470, EU636739) and rbc L (JN408523, JF344716, AF126414). Description Plants dioecious; whorls 408-675 µm in diameter; primary fascicles 7-12 cells; proximal cells cylindrical or ellipsoidal; distal cells subspherical, ellipsoidal or obovoidal; secondary fascicles abundant, covering the entire internode; spermatangia spherical or obovoidal, 1-3, few or abundant on primary or secondary fascicles, 5-7(-8) µm in diameter; carpogonial branches composed of 1-3 disc- or barrel shaped cells, arising from periaxial or proximal cells, short, 11-14 µm long; carpogonia with sessile, elongate cylindrical (with wavy margins) or fusiform trichogynes, 29-42 µm in length, 6-7.5 µm in diameter; gonimoblast initial developing from the protuberant side of the carpogonium; gonimoblast filaments with erect branches of 2-5 cells; carposporangia obovoidal, 10-13 µm in length, 6-8 µm in diameter. Remarks This species has been reported as S. huillensis (Necchi et al. 1993; Vis & Sheath 1999; Lam et. al. 2012) from North America. It has been described as having spermatangia arranged in clusters. However, this arrangement was not confirmed in this species and we have observed only abundant spermantangia in some specimens. The true arrangement in clusters in Sirodotia was observed only in S. assamica. S. aquiloamericana specimens are genetically divergent from those of S. huillensis from Africa. Thus, the North American material represents a distinct species that is here described. This species is most closely comparable to S. delicatuliformis Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov. based on the narrow carposporangia, 6-8.5 (-9.5) µm in diameter. However, S. aquiloamericana differs from S. delicatuliformis sp. nov. in having wider whorls (408-675 versus 169-491 µm in diameter) and geographical distribution (arid regions of North America versus southern North American and South America)., 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 102, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571, {"references":["NECCHI O. JR., SHEATH R. G. & COLE K. M. 1993. - Distribution and systematics of the genus Sirodotia (Batrachospermales, Rhodophyta) in North America. Journal of Phycology 29: 236 - 243 https: // doi. org / 10.1111 / j. 0022 - 3646.1993.00236. x","VIS M. L. & SHEATH R. G. 1999. - A molecular investigation of the systematic relationship of Sirodotia species (Batrachospermales, Rhodophyta) in North America. Phycologia 38: 261 - 266. https: // doi. org / 10.2216 / i 0031 - 8884 - 38 - 4 - 261.1"]}

Sirodotia kennedyi A.L.Szinte, J.C.Taylor & M.L.Vis (Fig. 6 G-I) Phycologia 194 (2020). S. masoalensis E. Fischer, D. Killmann & D. Quandt, Plant and Fungal Systematics 65: 164 (Fischer et al. 2020). TYPE. — Coll. M. P. Kennedy, 07.VII.2011 (holo-, SANDC [SANDC 19-566]; iso-, BHO [BHO A-0946]). TYPE LOCALITY. — Zambia, Mutinondo River, Mutinondo Wilderness, 12°16.101’S, 31°22.869’E. DISTRIBUTION. — Africa: Zambia and Madagascar. REPRESENTATIVE DNA SEQUENCES. — COI-5P (MT109276), rbc L (MN974518, MT109266). Description Plants dioecious; whorls 115-315 µm in diameter; primary fascicles, 3-5 cells; proximal cells cylindrical or ellipsoidal; distal cells obovoidal or ellipsoidal; secondary fascicles present, covering half to the entire internode; spermatangia spherical, on primary or secondary fascicles, 6-8 µm in diameter; carpogonial branches composed of 3-4 disc- or barrel shaped cells, arising from proximal cells of primary fascicles, short, 16-22 µm in length; carpogonia with sessile, elongate pear-shaped, elongate conical or irregularly shaped trichogynes, 25-40 µm in length, 7-11 µm in diameter; gonimoblast filaments with erect branches of one cell; carposporangia obovoidal or ellipsoidal, 9-10 µm in length, 5-7 µm in diameter. Remarks This species was recently described by Szinte et al. (2020) and it is most closely comparable to S. huillensis based on the reduced whorls (162-364 µm in diameter), shorter carposporangia (8-10 µm in length, respectively) and the occurrence in Africa. Sirodotia kennedyi differs from S. huillensis in number of primary fascicle cells, 3-5 versus 5-9(-10), respectively. In addition, they are genetically divergent. The recently described species S. masoalensis did not differ from S. kennedyi in morphology and DNA sequence and is here proposed as a synonym., 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 108, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571, {"references":["FISCHER E., GERLACH J., KILLMAN D. & QUANDT D. 2020 - The freshwater red algae (Batrachospermales, Rhodophyta) of Africa and Madagascar I. New species of Kumanoa, Sirodotia and the new genus Ahidranoa (Batrachospermaceae). Plant and Fungal Systematics 65: 147 - 166. https: // doi. org / 10.35535 / pfsyst- 2020 - 0010","SZINTE A. L., TAYLOR J. C., ABOSEDE A. T. & VIS M. L. 2020. - Current status of freshwater red algal diversity (Rhodophyta) of the African continent including description of new taxa (Batrachospermales). Phycologia 59: 1 - 13. https: // doi. org / 10.1080 / 0 0318884.2020. 1732149"]}

Sirodotia suecica Kylin (Fig. 6 J-N) Nova Acta Regiae Societatis Scientiarum Upsaliensis, ser IV, 3: 38 (Kylin 1912). — Batrachospermum suecicum (Kylin) Necchi & Entwisle, Phycologia 29: 486 (1990). Sirodotia fennica Skuja, Archiv für Protistenkunda 74: 297 (1931). Sirodotia sinica C. C. Jao, Sinensia 12: 267-270 (1941). Sirodotia tenuissima (Collins) Skuja ex Flint, American Journal of Botany 35: 431 (1948). Sirodotia acuminata Skuja ex Flint, American Journal of Botany 37:755 (1951). Sirodotia segawae Kumano, Botanical Magazine, Tokyo 95: 128-131 (1982). Sirodotia yutakae Kumano, Botanical Magazine, Tokyo 95: 126- 129 (1982). Sirodotia goebelii Entwisle & Foard, Australian Systematic Botany 12 (4): 610 (1999). TYPE. — H. Kylin, 3.VIII.1909 (lecto-, LD; isolecto-, UPS [UPS A-653877]). TYPE LOCALITY. — Sweden, Skäne, Osby; 56°23’01”N, 13°59’34”E. ADDITIONAL SPECIMEN EXAMINED. — BHO A-0264, SJRP 32581, SJRP 32582, SJRP 32583, NSW 799516, MEL 2033246 A, 2268154 A, WELT A 027220 (Appendix 1). DISTRIBUTION. — Africa, Asia, Australasia, Europe and North America. R EPRESENTATIVE DNA SEQUENCES. — COI-5P (MW053472, MW053473, MW053474), rbc L (MW053484, JF344724, JF344725) and LSU (MW053504, MW053505). Revised description Plants monoecious or dioecious; whorls (85-)135-850 µm in diameter; primary fascicles, 4-12(-13) cells; proximal cells cylindrical, obovoidal, ellipsoidal, fusiform or ovoidal; distal cells ellipsoidal, obovoidal or subspherical; secondary fascicles abundant, covering the entire internode; spermatangia spherical or ellipsoidal, 1-3, few or abundant on primary or secondary fascicles, (4-)5-9 µm in diameter; carpogonial branches composed of (1-)2-9 disc- or barrel shaped cells, short, 5-40 µm long, arising from periaxial, proximal or median cells of primary fascicles and cortical filaments, rarely on secondary fascicles; carpogonia with sessile, elongate cylindrical, ellipsoidal, elongate pear-shaped or irregularly shaped trichogynes, (15-)19-48 µm in length, (4-)5-16 µm in diameter; gonimoblast initial developing from the nonprotuberant side of the carpogonium; gonimoblast filaments with erect branches of 2-9 cells; carposporangia obovoidal, ellipsoidal, spherical or pear-shaped, 10-21 µm in length, 6-11 µm in diameter. Remarks This species has a broad geographic distribution and a broad range for the morphological features. It is comparable to the other species with large carposporangia and spermatangia 1-3 on primary fascicles (e.g. S. delicatula, 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). The species is clearly differentiated by the unique character of gonimoblast initial developing from the non-protuberant side of the carpogonium.Molecular data also showed the species to be clearly distinct from all others in the genus (rbc L, COI-5P and LSU). The heterotypic synonyms considered in this study were based on the analysis of types, protologues and when possible, molecular data. The morphological characters used to distinguish these species (S. fennica, S. sinica, S. tenuissima, S. acuminata, S. segawae, S. yutakae and S. goebelii) overlap most characters (breeding system, internode length, carpogonial branch growth and length and carpogonia length) of S. suecica and they are not useful due to the variation observed across this species. Molecular data for S. tenuissima and S. goebelii showed these taxa to have very similar rbc L sequences to S. suecica (Lam et al. 2012). Based on the analysis of type specimens and protologues of S. segawae and S. yutakae, we did not confirm the existence of specialized spermatangial branches on primary fascicles and secondary fascicles (S. yutakae) or on specialized filaments on cortical filaments or on shortened involucral filaments of carpogonial branches (S. segawae). We conclude that S. segawae, S. yutakae and S. sinica should be placed in synonymy with S. suecica. Overall, we accept only one taxon including these other names as synonyms, that is characterized by the gonimoblast initial developing from the opposite side of the basal protuberance of carpogonium., 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 pages 108-110, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571, {"references":["KYLIN H. 1912 - Studien uber die Schwedischen Arten der Gattungen Batrachospermum und Sirodotia nov. gen. Nova Acata Regiae Societatis Scentiarum Upsaliensis. Ser IV. 3 (3): 1 - 40.","SKUJA H. 1931. - Untersuchungen uber die Rhodophyceen des Su ¨ sswassers, 1 - 2. Archiv fur Protistenkunde 74: 297 - 309.","SZINTE A. L., TAYLOR J. C., ABOSEDE A. T. & VIS M. L. 2020. - Current status of freshwater red algal diversity (Rhodophyta) of the African continent including description of new taxa (Batrachospermales). Phycologia 59: 1 - 13. https: // doi. org / 10.1080 / 0 0318884.2020. 1732149","NECCHI O. JR., SHEATH R. G. & COLE K. M. 1993. - Distribution and systematics of the genus Sirodotia (Batrachospermales, Rhodophyta) in North America. Journal of Phycology 29: 236 - 243 https: // doi. org / 10.1111 / j. 0022 - 3646.1993.00236. x","LAM D. W., ENTWISLE T. J., ELORANTA P., KWANDRAS J. & VIS M. L. 2012. - Circumscription of species in the genus Sirodotia (Batrachospermales, Rhodophyta) based on molecular and morphological data. European Journal of Phycology 47: 42 - 50. https: // doi. org / 10.1080 / 09670262.2011.645885"]}

Sirodotia cryptica Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov. (Fig. 4 F-J) TYPE. — F. R. Borges, 15.IV.2014, (SJRP [SJRP 32575]). TYPE LOCALITY. — Brazil, Goiás, Highway GO-070, between the municipalities of Jussara and Itaberaí; 16°00’32.7”S, 48°55’55.9”W. ADDITIONAL SPECIMENS EXAMINED. — SJRP 31923 and SJRP 31925 (Appendix 1). ETYMOLOGY. — The species epithet indicates that the alga is cryptic with another species described in this study (S. amazonica Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov.). DISTRIBUTION. — South America, Brazil (midwestern). REPRESENTATIVE DNA SEQUENCES. — COI-5P (KF010488, KF010491, MW053463,), rbc L (KC951865, KC951869, MW053479) and LSU (MW053494, MW053495, MW053498). Description Plants monoecious or dioecious; whorls 223-559 µm in diameter; primary fascicles (4-)5-10(-11) cells; proximal cells cylindrical or ellipsoidal; distal cells spherical, ellipsoidal or obovoidal; 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, proximal or median cells of primary fascicles, rarely on the secondary fascicles or cortical filaments, short, 10-25 µm long; carpogonia with sessile, elongate cylindrical (with wavy margins), elongate-conical or fusiform trichogynes, sometimes with anomalous shapes (bent end), (24-)26-58 µm in length, 9-13(-15) µm in diameter; gonimoblast initial developing from the protuberant side of the carpogonium; gonimoblast filaments prostrate with erect branches of 2-5 cells; carposporangia subspherical, ellipsoidal or obovoidal, 10-17 µm in length, (7-)8-11 µm in diameter. Remarks This species is morphologically indistinguishable from S. amazonica Necchi, N.L.Rossignolo & M.O.Paiano, sp. nov. that also occurs in Brazil, but is genetically divergence and thus, it is here described as a new species., 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 104, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571

Sirodotia huangshanensis Z.X.Shi & S.L.Xie Journal of Tropical and Subtropical Botany 12 (1): 2 (2004). Type specimen is not available for analysis; in the protologue the species was distinguished based on breeding system (monoecious) and the presence of monosporangia in the secondary fascicles. In Sirodotia, it has been shown that distinguishing species based on breeding system (monoecious, dioecious or polyoecious) is not a reliable taxonomic character (Umezaki, 1960). The presence of monosporangia may be a misinterpretation of carposporangia based on size and position., 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 110, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571, {"references":["UMEZAKI I. 1960. - On Sirodotia delicatula Skuja from Japan. Acta Phytotaxonomica et Geobotanica 18: 208 - 214."]}

Sirodotia cirrhosa Skuja ex M.S.Balakrishnan & B.B.Chaugule Indian Batrachospermaceae: 242 (1980). Type specimen not available for analysis.

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)., 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 104, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571, {"references":["JOHNSTON E. T., LIM P. - E., BUHARI N., KEIL E. J., DJAWAD M. I. & VIS M. L. 2014. - Diversity of freshwater red algae (Rhodophyta) in Malaysia and Indonesia from morphological and molecular data. Phycologia 53: 329 - 341. https: // doi. org / 10.2216 / 13 - 223.1","NECCHI O. JR. 1991. - The Section Sirodotia of Batrachospermum (Rhodophyta, Batrachospermales) in Brazil. Archiv Hydrobiologie, Suppl. Algological. Studies 62: 17 - 30.","NECCHI O. JR., SHEATH R. G. & COLE K. M. 1993. - Distribution and systematics of the genus Sirodotia (Batrachospermales, Rhodophyta) in North America. Journal of Phycology 29: 236 - 243 https: // doi. org / 10.1111 / j. 0022 - 3646.1993.00236. x","NECCHI O. JR., VIS M. L. & OLIVEIRA M. C. 2007. - Phylogenetic relationship of Sirodotia species (Batrachospermales, Rhodophyta) in North and South America. Cryptogamie, Algologie 27: 117 - 127.","PAIANO M. O. & NECCHI O. Jr. 2013. - Phylogeography of the freshwater red alga Sirodotia (Batrachospermales, Rhodophyta) in Brazil. Phycological Research 61: 249 - 255. https: // doi. org / 10.1111 / pre. 12027","UMEZAKI I. 1960. - On Sirodotia delicatula Skuja from Japan. Acta Phytotaxonomica et Geobotanica 18: 208 - 214."]}

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., 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 102, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571

Sirodotia Kylin Nova acta Regiae Societatis Scientiarum Upsaliensis, ser. IV, 3: 38 (Kylin 1912). Section Sirodotia (Kylin) Necchi & Entwisle, Phycologia 29, 4: 485 (Necchi & Entwisle 1990). TYPE SPECIES. — Sirodotia suecica Kylin, Nova acta Regiae Societatis Scientiarum Upsaliensis Ser. IV, 3: 38 (1912). DISTRIBUTION. — The genus has been collected in temperate, tropical, subtropical and sub-polar regions of North and South America, Africa, Asia, Australasia and Europe. Revised description Plants monoecious, dioecious or polyoecious, bluish green to yellowish green; branching irregular; whorls well-developed or reduced, contiguous or separated, obconical or pear-shaped; cortical filaments of the main axis well-developed, one or two layers; primary fascicles with cells variable in shape, cylindrical, ellipsoidal, obovoid, subspherical or spherical; secondary fascicles abundant, covering the entire or two-thirds of internode, equal to or less than the length of the primary fascicles; spermatangia spherical, subspherical or obovoid on primary or secondary fascicles; carpogonial branches well-differentiated from the fascicles, straight, rarely curved, developing from the periaxial, proximal, median and distal cells of primary fascicles or cortical filaments, rarely on the secondary fascicles, short, composed of disc- or barrel-shaped cells; involucral filaments few and short, composed 1-4 cylindrical or ellipsoidal cells; carpogonia asymmetrical, with a hemispherical protuberance in the basal portion; trichogynes sessile and cylindrical, cylindrical-elongated, conical-elongated, clavate, fusiform, lageniform or ellipsoidal, with or without wavy margins; carposporophyte diffuse extending along the internode; gonimoblast filaments develop on the same side or opposite side of the basal protuberance of the carpogonium; gonimoblast filaments prostrate and indeterminate, composed of 1-5 cylindrical cells, producing short, erect branches, formed by cylindrical or ellipsoidal cells, with terminal or sub-terminal carposporangia; carposporangia large or small, obovoidal, ellipsoidal or subspherical. Diagnostic characters The genus is characterized by diffuse carposporophytes composed of prostrate gonimoblast filaments producing short, erect filaments with terminal carposporangia; and asymmetric carpogonium, with a semi-spherical basal protuberance; the shape of the whorls (obconical or pear-shaped) can be used as a complementary character; however, it is not exclusive to the genus and can be observed in species of Kumanoa (Necchi & Vis 2012), Paludicola (Vis et al. 2020) and to varying degrees in other genera of Batrachospermales. KEY TO THE SPECIES OF THE GENUS SiRodoTia KYLIN 1. Carposporangia small, 5-10 µm in length..................................................................................................... 2 — Carposporangia large, 10-21 µm in length................................................................................................... 3 2. Primary fascicle 3-5 cells; erect gonimoblast filaments with 1 cell.................................................................................................................................................................... S. kennedyi A.L.Szinte, J.C.Taylor & M.L.Vis — Primary fascicle (5-)6-10 cells; erect gonimoblast filaments with 2-4 cells............................................................................................................................................... S. huillensis (Welwitsch ex West & G.S.West) Skuja 3. Spermatangia arranged in clusters........... S. assamica Necchi, N.L.Rossignolo, F.Yasmin, J.A.West & Ganesan — Spermatangia isolated or in groups of 2-3..................................................................................................... 4 4. Gonimoblast initial developing from the non-protuberant side of the carpogonium................ S. suecica Kylin — Gonimoblast initial developing from the protuberant side of the carpogonium............................................ 5 5. Known distribution restricted to Asia (Indonesia, Japan and Malaysia)............................... S. delicatula Skuja — Known distribution in the Americas............................................................................................................. 6 6. Carposporangia wide, 8-13 µm in diameter........................................................................................................................................................................................................ S. amazonica sp. nov. and S. cryptica sp. nov — Carposporangia narrow, 6-8.5 (-9.5) µm in diameter................................................................................... 7 7. Known distribution in southern North America (Costa Rica) and South America (Brazil).............................................................................................................................................................. S. delicatuliformis sp. nov. — Known distribution in arid regions of North America (United States, Mexico)............................................................................................................................................................................ S. aquiloamericana sp. nov., 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 pages 100-101, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571, {"references":["KYLIN H. 1912 - Studien uber die Schwedischen Arten der Gattungen Batrachospermum und Sirodotia nov. gen. Nova Acata Regiae Societatis Scentiarum Upsaliensis. Ser IV. 3 (3): 1 - 40.","VIS M. L., LEE J., ELORANTA P., CHAPUIS I. S., LAM D. W. & NECCHI O. JR. 2020. - Paludicola gen. nov. and revision of the species formerly in Batrachospermum section Turfosa (Batrachospermales, Rhodophyta). Journal of Phycology 56: 844 - 861. https: // doi. org / 10.1111 / jpy. 13001"]}

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)., 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, {"references":["PAIANO M. O. & NECCHI O. Jr. 2013. - Phylogeography of the freshwater red alga Sirodotia (Batrachospermales, Rhodophyta) in Brazil. Phycological Research 61: 249 - 255. https: // doi. org / 10.1111 / pre. 12027"]}

Sirodotia gardneri Skuja ex L.Flint American Journal of Botany 37: 754 (1951). Type specimen is not available for analysis.The type specimen analyzed by Necchi et al. (1993) was a male plant and therefore key characteristics could not be confirmed., 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 110, DOI: 10.5252/cryptogamie-algologie2021v42a8, http://zenodo.org/record/7828571, {"references":["NECCHI O. JR., SHEATH R. G. & COLE K. M. 1993. - Distribution and systematics of the genus Sirodotia (Batrachospermales, Rhodophyta) in North America. Journal of Phycology 29: 236 - 243 https: // doi. org / 10.1111 / j. 0022 - 3646.1993.00236. x"]}

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).