Nocturama novamundensis Necchi & Entwisle, 2016

Jr, Orlando Necchi, Entwisle, Timothy J., Branco, Ciro C. Z. & Paiano, Monica O., 2016, First record of Nocturama (Batrachospermales, Rhodophyta) in South America, with the description of a new species N. novamundensis, Phytotaxa 278 (3), pp. 273-280 : 274-279

Nocturama novamundensis Necchi & Entwisle , sp. nov.

Figures 3–13 .

Holotype:— Brazil: Rio Grande do Sul, Parque Estadual Florestal do Turvo, Tigre River , 27°12’25”S, 53°50’02”W, 18.viii.2007, C. C. Z. Branco et al. ( SJRP29741 ) ; Isotype MEL 2401959.

Etymology:— novamundensis , from the Latin term for New World ( Mundus Novus), the somewhat romantic and misleading term for the known distribution of this species, the ‘Americas’. The epithet is in harmony with that of the type species, antipodites , which is based on a colloquial term used for the inhabitants of Australia and New Zealand (being, it seems, on the ‘opposite side of the Earth’).

Material examined:— Paraná: Foz do Iguaçu, Iguaçu National Park, 25°09’38”S, 53°49’44”W, 02.v.2008, C. C. Z. Branco et al. ( SJRP29760 ). Rio Grande do Sul: Parque Estadual Florestal do Turvo , Calisto River , 27°13’49”S, 53°54’92”W, 17.viii.2007, C. C. Z. Branco et al. ( SJRP29739 ) ; Fábio River, 27°16’32”S, 54°00’56”W, 17.viii.2007, C. C. Z. Branco et al. ( SJRP29735 ). Canela, Caracol State Park , Tiririca River , 29°18’59”S, 50°51’01”W, 02.vi.2008, C. C. Z. Branco et al. ( SJRP29725 ). Santa Catarina: Blumenau, Serra do Itajaí National Park , Prata River , 27°02’17”S, 49°05’57”W, 28.v.2008, C. C. Z. Branco et al. ( SJRP29745 ). São Paulo: Cananéia: Cardoso Island , Perequê River , 25°05’37”S, 47°55’45”W, 13.vi.1984, O. Yano & M. G. L. Wanderley ( SP187226 ) ; between Ipanema and Cambriú beaches, 25°09’41”S, 47°55’48”W, 29.xi.1983, D. M. Vital ( SP186936 ). Santo Antonio do Pinhal, Route SP-50, 2 km from town, 22 o 49’06’’S, 45 o 44’58’’W, 23.x.1996, O. Necchi Jr. & C. C. Z. Branco ( SJRP23376 ). São Luiz do Paraitinga , Ponte Preta Farm, Chapéu Stream, 23°12’34”S, 45°20’10”W, 14.vii.1983, O. Yano ( SP187153 ) .

Geographic distribution:— the species occurs in four forested Brazilian biomes ( Ab’Saber 2006): dense ombrophyllous forest (Atlantic rainforest), mixed ombrophyllous forest (subtropical rainforest with Araucaria ), deciduous and semi-deciduous seasonal forests in southeastern and southern Brazil ( Fig. 14 ).

Environmental characteristics (n = 7): water temperature16.6 ± 3.4 oC (mean ± standard-deviation); specific conductance 31 ± 8 μS cm-1; turbidity 5 ±3 NTU; pH 6.8 ± 0.5; dissolved oxygen 5,4 ± 1.2; current velocity 55 ± 25 cm s-1; depth 19± 5 cm; shaded stream or river segments, with variable shading degrees: partly shaded (58% of collecting sites), shaded (28%) and heavily shaded (14%). These environmental data are summarized from Necchi et al. (1999) and Branco et al. (2014), in which this species is reported as B. arcuatum .

Description:— thalli dioecious, brownish, moderately mucilaginous, abundantly and irregularly branched, up to 7 cm long, 300–535 μm in diameter. Whorls spheric or barrel-shaped, separated or contiguous ( Figures 3, 6 ). Internode 150–350 μm in length. Rhizoidal filaments composed of cylindrical cells only. Primary fascicles curved, composed of 8–15 cells; proximal cells cylindrical or ellipsoid, distal cells ellipsoid or obovoid ( Figures 6–8 ). Secondary fascicles lacking, few and sparse in older thalli ( Figures 3, 6 ). Spermatangia spherical or obovoid, terminal or sub-terminal on distal cells of primary fascicles, 3.5–6.0 μm in diameter. Carpogonial branches straight, 30–70 μm in length, on pericentral or proximal fascicle cells, composed of 3–10 cells, undifferentiated from fascicle cells; proximal cells cylindrical or ellipsoid, distal cells cylindrical or short-cylindrical; involucral filaments long (3–5 cells) in proximal portion, short (1–2 cells) in distal portion ( Figures 9–11 ). Carpogonia symmetric, 13–25.5 μm in length; trichogyne club-shaped, sessile ( Figures 10–11 ).

Carposporophytes pedicellate or indistinctly pedicellate, 1–2 per whorl, dense, spherical, 75–175 μm in diameter; carposporophyte inserted in the inner or outer part of the whorls; diameter to whorl radius ratio 0.5–1.0; gonimoblast filaments 3–5 cells ( Figures 3–5, 12–13 ). Carposporangia obovoid, 10–18 μm in length, 7–10 μm in diameter ( Figures 12–13 ).

DNA sequences:— rbc L-KX764639 (SJRP29725), KX764640 (SJRP29745); SSU-KX764641 (SJRP29725), KX764642 (SJRP29745)).

Diagnostic characters:— the species can be distinguished from N. antipodites in having curved rather than straight primary fascicles, composed of non-audouinelloid cells ( Table 1). In addition, Brazilian populations of N. novamundensis are dioecious, whereas the Australian specimens of N. antipodites are monoecious, only rarely dioecious. Sequence divergences for both molecular markers analyzed corroborate the morphological characters, indicating a clear separation of the two species.

Circumscription of Nocturama :— with the addition of a new species, the circumscription of Nocturama remains the same except for the fascicle cells not always being audouinelloid ( Entwisle et al. 2016). The Southern Hemisphere (ex-Gondwanan) distribution, red to brownish colour of the thallus, generally well-shaded habitat and the lack of secondary fascicles are useful if not exclusive diagnostic characters for the genus.

Within the Batrachospermales , Nocturama more closely resembles members of the genus Sheathia and section Batrachospermum of the genus Batrachospermum in lacking secondary fascicles and having long and undifferentiated carpogonial branches, short and usually club-shaped trichogynes, and pedicellate carposporophytes. It can be distinguished from both of those taxa by the presence of only one or two large carposporophytes per whorl (carposporophyte diameter-to-whorl-radius ratio ranging from 0.5 to 1.0). In contrast, members of Sheathia and section Batrachospermum typically have more numerous carposporophytes (two to six, exceptionally up to ten, per whorl) that are much smaller than whorls (carposporophyte diameter-to-whorl-radius ratio <0.5) ( Kumano 2002, Salomaki et al. 2014). This discovery highlights yet again the richness and distinctiveness of the Batrachospermales in the Southern Hemisphere, and that there are important discoveries still to be made even among existing collections.

Figures

FIGURE 14. Distribution map of Nocturama novamundensis Necchi & Entwisle sp. nov. in Brazil.

FIGURES 3–13. Nocturama novamundensis Necchi & Entwisle sp. nov. 3–4. Whorls and carposporophytes (arrow); 5. Developing carposporophyte showing pedicellate (arrow); 6. Whorls showing curved primary fascicles (arrows); 7–8. Details of primary fascicles showing the curved disposition; 9. Entire carpogonial branch showing trichogyne (arrow); 10–11. Apical part of carpogonial branches showing young (10) and mature carpogonia; 12–13. Details of an intact (12) and a squashed carposporophyte. Scale bars: 250 μm for figures 3; 100 μm for figures 4–6; 50 μm for figures 7–8; 25 μm for figures 9, 12–13; 10 μm for figures 10–11.