Danaea ubatubensis Keskiniva & Tuomisto, 2024

Keskiniva, Venni & Tuomisto, Hanna, 2024, Danaea (Marattiaceae) keeps diversifying, part 1: eighteen new species, Willdenowia 53 (3), pp. 173-228 : 221-223

17. Danaea ubatubensis Keskiniva & Tuomisto , sp. nov. (D. subg. Holodanaea) – Fig. 31, 32.

Holotype: Brazil, São Paulo, Ubatumirim, Parque Estadual da Serro do Mar , Núcleo Picinguaba , trail along Rio da Fazenda starting at Casa de Farinha , 23°20'S, 44°50'W, 125 m, 6 Mar 2008, Christenhusz 4910 ( SP! (mounted on 2 sheets: 473402); isotypes: AAU!, MO! (mounted on 2 sheets: 6303081), TUR!, UC! (1930838), Z!).

Diagnosis — Similar to and co-occurring with Danaea excurrens Rosenst. , differing in having no serrations in pinna apices (vs pinna apices usually serrate), terminal pinnae often replaced by bud (vs always present), sometimes having more pinna-pairs (11–16 vs 5–16), generally longer pinnae (12–16 cm vs 5–15 cm) that are more elliptic (vs parallel-sided or spathulate), longer pinna apices (1.9–2.2 cm vs 0.5–1.5 cm), veins both simple and forked at costae (vs usually mostly forked either at costae or above), often symmetrical pinna bases (vs usually asymmetrical). Genetically differs from all other species of Danaea in locations 629 (A vs G), 857 (A vs G) of atpB reference sequence; 226 (G vs A or gap), 257 (T vs A or G), 685 (G vs C or T), 867 (T vs A or G) of trnL-F reference sequence; 417 (T vs C of rbcL reference sequence; 438–465 (gap vs no gap), 466 (G vs A or T), 469 (T vs A or G), 766 (T vs C) of rpl32 reference sequence. Unique in D. subg. Holodanaea in locations 413 (G vs A or T), 435 (A vs G) of rpl32 reference sequence; 240 (A vs C or T) of trnL-F reference sequence.

Description — Rhizomes radial, orientation not certain, 1.5–2.0 cm in diam. Sterile leaves 66–118 cm long; petioles 37–57 cm long, with 1–3 nodes, not winged; laminae 29–60 × 18–26 cm, lanceolate to obovate, imparipinnate or paripinnate, 11–16 pinna-pairs, medial pinnae 2.0– 2.9 cm apart, bicolorous, dark green adaxially, light green abaxially (or dark brown adaxially and light brown abaxially when preserved in alcohol before drying), laminar texture rather thin, rachises not winged or very narrowly winged distally, wings to 0.1 mm wide; terminal pinnae 9.0–10 × 1.5–1.8 cm, oblong to lanceolate, bases acute, apices 1.4–1.6 cm long, (long-) acuminate, margins of apices sinuate at apex, serrulate at shoulder of pinna; largest lateral pinnae 12–16 × 1.5–2.1 cm, 5.4–7.7 times as long as wide without apex, widest at middle or parallel-sided, slightly ascending, bases asymmetrical or symmetrical, acute, apices 1.9–2.2 cm long, long-acuminate, margins of apices sinuate to crenulate at apex, crenulate to serrulate at shoulder of pinna; veins 10–15 per cm, simple or forked at costae or rarely above. Fertile leaves 100 cm long; petioles 57 cm long, with 1 node, not winged; laminae c. 43 × 14 cm, parallel-sided, paripinnate, 13 pinna-pairs, not winged; largest lateral pinnae c. 7.3 × 0.7–0.9 cm, parallel-sided, bases obtuse, apices mucronate to acuminate, margins of apices sinuate. Juveniles with elliptic, oblong or lanceolate laminae, terminal pinnae elliptic to lanceolate, lateral pinnae elliptic, apices acuminate to acute, smallest observed pinnate juvenile leaf 10 cm long with 4 pinna-pairs.

Distribution and habitat — Known only from the Brazilian Atlantic Forest in Ubatuba, São Paulo state, southern Brazil, from 125–1000 m. Fig. 33.

Conservation status — We place Danaea ubatubensis in the Critically Endangered (CR B1ab(iii)+2ab(iii)) category ( IUCN 2012). It is known from only two specimens, which corresponds to the CR category. The collection localities were only 6 km apart, and an Area of occupancy of <10 km 2 also corresponds to the CR category. Both collections are from Parque Estadual da Serro do Mar, Núcleo de Picinguaba, but the Atlantic forests of Brazil are only a fragment of their original size and the extent and quality of the habitats suitable for D. ubatubensis are continuing to decline. Given that D. ubatubensis is genetically distant from all the other Holodanaea species we have sampled, it makes an important contribution to the genetic diversity of the genus.

Etymology — Named after the municipality of Ubatuba, where both known specimens were collected.

Remarks — Danaea ubatubensis occurs in the same area as D. excurrens but is genetically clearly distinct and can most easily be identified by its larger number of pinnae (11–16 vs 5–8 pairs). However, our genetic studies suggest that D. excurrens is a variable species that does not always display the most striking characteristics of the type, namely the small number of pinnae that are narrow and spathulate and have sparse, simple veins. Instead, most specimens of D. excurrens are more similar to D. moritziana , although they have narrower pinnae and often creeping rhizomes (vs always erect in D. moritziana ).

Danaea ubatubensis differs from D. excurrens s.l. in larger size (66–118 cm vs 35–62 cm), having entire apices (vs apices usually serrate), often with terminal pinnae replaced by a bud (vs always present but sometimes interrupted by a bud), and generally having longer pinnae (12–16 cm vs 5.3–15 cm long). The narrow-elliptic pinna shape of D. ubatubensis differs from both the spathulate shape of typical D. excurrens and the more parallel-sided shape of the majority of the specimens. From the latter, D. ubatubensis further differs in having acute pinna bases (vs obtuse) that can be symmetrical (vs always asymmetrical), longer pinna apices (1.9–2.2 cm vs 0.5–1.5 cm long), and a mixture of simple veins and veins forked at the costae (vs mostly forked at the costae or above).

Additional specimens examined — BRAZIL: SÃO PAULO: Ubatuba, Parque Estadual da Serra do Mar, Núcleo de Picinguaba , Pico do Cuscuzeiro trail, close to border between Rio de Janeiro and São Paulo, 23°18'S, 44°48'W, 1000 m, 2001, Salino 7284 (NY!)