Danaea robbinmoranii Keskiniva & Tuomisto, 2024

Keskiniva, Venni & Tuomisto, Hanna, 2024, Danaea (Marattiaceae) keeps diversifying, part 1: eighteen new species, Willdenowia 53 (3), pp. 173-228 : 219-220

16. Danaea robbinmoranii Keskiniva & Tuomisto , sp. nov. (D. subg. Holodanaea) – Fig. 29, 30.

Holotype: Costa Rica, San José, along entrance road to University of San Ramón’s biological field station “Alberto Brenes” , c. 1.5 km from main road San Ramón–La Tigra, 10°14'N, 84°38'W, 800 m, 23 Jan 2001, Moran 6350 ( CR! (INB0003704244); isotype: NY! (03881060)).

Diagnosis — Most closely related to Danaea vanderwerffii Tuomisto & Keskiniva but differing in proximal pinnae not as reduced (largest lateral pinnae 2–4 times as long as proximal pinnae vs over 5 times as long), generally narrower fertile pinnae (0.5–1.1 cm vs 0.8–1.6 cm wide), apices more often with serrations (vs usually crenulate), sterile pinnae generally shorter (to 16 vs to 25 cm long), generally more nodes on petioles (0–3 vs 0–1). Genetically differs in location 455 (gap vs T), 752 (T vs C) of rpl32 reference sequence; 906 (C vs T) of trnL-F reference sequence. Morphologically similar to D. cuspidopsis Keskiniva & Tuomisto , but wings usually present along all of rachises and sometimes part of petioles (vs only in distal part of lamina) and wings wider (to 0.7–2 mm vs to 0.1–0.7 mm wide), generally fewer pinna-pairs (7–16 vs 13–20) that are stockier (largest lateral pinna length without apex 3–6 vs 5–8 times as long as wide), and spaced further apart (medial pinnae 2.9–3.5 cm vs

1.4–2.5 cm apart). Genetically differs in locations 43 (T vs A), 222 (A vs G), 231 (A vs G), 257 (C vs A), 327 (C vs T), 396 (A vs T), 424 (C vs A), 450 (T vs gap), 455 (T vs gap), 465 (T vs G), 466 (T vs A), 469 (G vs A), 587 (G vs A), 713 (C vs T), 758–762 (insertion of ATACT vs gap), 737 (A vs G), 749 (G vs T), 863 (A vs G), 865 (A vs G) of rpl32 reference sequence; 192 (C vs A), 233 (A vs C), 248–252 (gap vs insertion of ATTAG), 265 (G vs A), 393 (G vs A), 399 (T vs C), 538 (G vs A), 665 (T vs C), 728–732 (gap vs insertion of AATA), 740 (T vs C) of trnL-F reference sequence. Unique among Danaea in location 134 (T vs C) of rpl32 reference sequence.

Description — Rhizomes erect and radial, 1.0– 2.5 cm in diam., short, to at least 7 cm long. Sterile leaves 59–94 cm long; petioles 19–42 cm long, with 0–3 nodes, not winged or winged only distally; laminae 33–63 × 10–25 cm, oblong to lanceolate or elliptic, imparipinnate or (rarely) paripinnate, 7–16 pinna-pairs, proximal pinnae smallest and more distant, medial pinnae 2.9–3.5 cm apart, bicolorous, adaxially dark green, abaxially clearly paler, whitish to light green (or dark brown adaxially, light brown abaxially when preserved in alcohol before drying), laminar texture thin, rachises winged (at least in distal part of lamina), wings to 0.7–2 mm wide; terminal pinnae 6.9–14.2 × 1.7–2.6 cm, lanceolate to oblong, bases acute to obtuse, apices 1.5–2.6 cm long, acuminate, margins of apices serrate to serrulate; largest lateral pinnae 9.4–15.7 × 2.0– 3.5 cm, 3.0–6.1 times as long as wide without apex, parallel-sided (to widest above middle), slightly ascending (or perpendicular to rachis), bases symmetrical (obtuse) to asymmetrical (auriculate proximally, obtuse (or acute) distally), apices 1.1–2.2 cm long, acuminate to caudate, margins serrate to serrulate at shoulders of pinnae, apices serrulate, serrate, crenate or crenulate; veins 12–17 per cm, mostly simple or mixture of simple and paired at costae. Fertile leaves 53–88 cm long; petioles 20–47 cm long, 0–3 nodes; laminae 27–52 × 6–17 cm, oblong or long-elliptic, imparipinnate (or possibly paripinnate), 8–15 pinna-pairs; terminal pinnae c. 5.2 × 0.4–0.9 cm, lanceolate, bases acute, apices acuminate; largest lateral pinnae 7.6–11 × 0.5–1.1 cm, linear-oblong, (slightly) ascending, bases symmetrical (obtuse) to asymmetrical (auriculate proximally, obtuse distally), apices 0.7–1.6 cm long, long-acuminate, margins of apices serrulate, crenulate or crenate. Juveniles not known.

Distribution and habitat — Known from Costa Rica from 50–1082 m, from primary and secondary rainforests. The species has been found growing on a steep clay creek bank and epipetric on a rock face. Fig. 13.

Conservation status — We place Danaea robbinmoranii in the Least Concern (LC) category ( IUCN 2012). It has an Area of occupancy of 68 km 2, which corresponds to the EN category, and an Extent of occurrence of 28,079 km 2, which corresponds to the NT category. However, D. robbinmoranii seems to be rather abundant in the Costa Rican lowlands, is known from 17 collections, and has been collected from several protected areas (Parque Nacional Guanacaste, Nectandra Biological Preserve, Parque Nacional Braulio Carrillo, and Parque Nacional Corcovado in Costa Rica; Reserva Biológica Indio Maíz in Nicaragua). There appears to be no imminent threat to all its subpopulations.

Etymology — Named for Robbin C. Moran, who has made important contributions to fern systematics and fern-related education and who also collected the type specimen of this species.

Remarks — Danaea robbinmoranii is one of the species in a complex that was previously referred to D. moritziana . It is morphologically most similar to D. cuspidopsis , with which it co-occurs in Costa Rica but at lower elevations (generally below vs above 1000 m). Danaea robbinmoranii is perhaps best separated from D. cuspidopsis by the rachis wings, which are wider (to 0.7–2 mm vs to 0.1–0.7 mm wide) and usually extend along all of the rachises and sometimes part of the petioles as well (vs adult leaves only winged in the distal part of the rachis), the pinnae being further apart on the rachises (medial pinnae 3.0– 3.5 cm vs 1.4–2.5 cm apart) and abaxially being even more starkly whitish. Danaea robbinmoranii further differs from D. cuspidopsis in having generally fewer pinnae (7–16 vs 13–20 pinna-pairs) that are stockier (largest lateral pinnae 3–6 vs 5–8 times as long as wide without apex), by its smaller size (sterile leaves max. 94 cm vs max. 120 cm long), and probably shorter rhizomes (to 7 cm tall vs to 25 cm tall).

Genetically, Danaea robbinmoranii was resolved as sister to D. vanderwerffii from Panama, with which it shares a starkly whitish abaxial colour but differs in the proximal pinnae being larger (vs strongly reduced; smallest pinnae ¼–½ as long as largest lateral pinnae vs at most 1/5 and usually less than 1/10). In addition, the apices of the sterile pinnae in D. robbinmoranii are often serrulate (vs crenate), the fertile pinnae are often narrow- er (0.5–1.1 cm vs 0.8–1.6 cm wide), the sterile pinnae do not grow as large (to 16 vs to 25 cm long), and there are often more petiolar nodes (0–3 vs 0–1).

Danaea robbinmoranii is similar in habit to the genetically distant Danaea alata Sm. that has a distribution in the Lesser Antilles and Venezuela (vs Costa Rica and Nicaragua) but differs in having erect rhizomes (vs decumbent in D. alata ), generally stockier pinnae (largest lateral pinnae 3–6 vs 4–9 times as long as wide without apex), and often forked veins (vs always simple) that are closer (12–17 vs 7–14 veins per cm).

Additional specimens examined — COSTA RICA: ALAJUELA: Upala, Bijagua, El Pilón, Cabaceras del Río Celeste, 10°49'N, 84°27'W, 700 m, 13 Nov 1987, Herrera 1245 (CR!, UC!); San Ramón, Nectandra Biological Preserve, Ocotea area, 10°11'N, 84°31'W, 1082 m, 23 Jan 2011, Nitta 851 (UC!); northern slope of ridge along quebrada draining eastward to Río Cataratitas, c. 20 km NW of San Ramón, 10°13'N, 84°32'W, 850 m, 3 Feb 1986, Smith 2248 (MO!, NY!, UC!); GUANACASTE: La Cruz, Santa Cecilia, Finca Montecele, on way to Río Colón and toward Cerro Campana, 10°58'N, 85°26'W, 650–800 m, 12 Apr 2008, Rojas 8404 (MO!); La Cruz, Santa Cecilia, Finca Montecele, on way to Río Colón and toward Cerro Campana, 10°58'N, 85°26'W, 700–1000 m, 13 Apr 2008, Rojas 8417 (MO-2!); HEREDIA: Finca La Selva, OTS Field Station on Río Puerto Viejo just E of its junction with Río Sarapiqui, 100, 22 Jun 1981, Hammel 10905 (CR!, DUKE, F!, MO!); Along Rio Peje about 0.5 km SW of back end of Vargas property, approx. where an imaginary line between Magsasay and Puerto Viejo de Sarapiqui would cross Río Peje, 20 Feb 1982, Hammel 11215 (DUKE, F!, MO!); LIMÓN: Siquirres, Las Brisas de Pacuarito, 300 m, 18 Apr 1985, Gómez 23409 (MO!); Río Danto, path to Las Brisas, Pacuarito, Siquirres, 21 May 1985, Gómez 23622 (MO!, UC!); PUNTARENAS: Golfito, P. N. Corcovado, Peninsula de Osa, Cerro Rincón, 08°31'N, 83°28'W, 700–800 m, 30 Jan 1998, Azofeifa 623 (CR!, NY!); Along road between Chacarita and Rincón de Osa, c. 6 km W of Interamerican Highway at Chacarita, 08°45'N, 83°18'W, 160 m, 2 Mar 1985, Croat 59710 (MO!); c. 3 miles E of Rincón de Osa, 08°42'N, 83°29'W, 250–350 m, 17 Jul 1967, Evans 2761 (U!); Parque Nacional Corcovado, Estación Los Patos, 08°34'N, 83°31'W, 120 m, 1 Apr 1988, Hammel 16631 (CR!, UC!); Osa Peninsula, on ridge 9.5 km W of Rincón de Osa, 600 m, 17 Jul 1967, Mickel 2753 (NY!, U!); SAN JOSÉ: Vazquez de Coronado, Parque Nacional Braulio Carrillo, Estación Carrillo, Quebrada Sandijuela, 500 m, 25 Jul 1984, Gómez 22921 (UC!). — NICARAGUA: RÍO SAN JUAN: Reserva Indio-Maíz, Municipality of Castillo, along Caño Chontaleño, 11°06'N, 84°14'W, 150–200 m, 14 Feb 1997, Rueda 5791 (MO!).