Danaea antioquiana Keskiniva & Tuomisto, 2024

Keskiniva, Venni & Tuomisto, Hanna, 2024, Danaea (Marattiaceae) keeps diversifying, part 1: eighteen new species, Willdenowia 53 (3), pp. 173-228 : 184-187

4. Danaea antioquiana Keskiniva & Tuomisto , sp. nov. (D. subg. Danaea ) – Fig. 9, 10.

Holotype: Colombia, Antioquia, San Luis, Reserva “Río Claro” , 06°00'N, 74°56'W, 300 m, 1 Feb 2015, Kessler 14754 ( TUR!).

Diagnosis — Morphologically very similar to Danaea nodosa (L.) Sm. but genetically differs in locations 562 (T vs C) of atpB reference sequence; 123 (G vs A) and 282 (A vs G) of trnL-F reference sequence; 636–638 (gap vs AAA), 642 (A vs C) and 673 (A vs G) of rpl32 reference sequence. Similar to D. sellowiana C. Presl , but generally has more parallel-sided and straight pinnae (vs narrow-elliptic and slightly curved) and dries a more yellowish colour (vs bluish to greyish green). Genetically differs from D. sellowiana in locations 74 (A vs G) of trnL-F reference sequence; 425 (T vs C) and 445 (G vs A) of rpl32 reference sequence.

Description — Rhizomes creeping, dorsiventral, 4 cm in diam., leaf bases in two rows, at least to 14 cm long. Sterile leaves 108–217 cm long; petioles 55–110 cm long, no nodes, not winged; laminae 53–108 × 30–60 cm, long-obovate, imparipinnate, 11–19 pinna-pairs, medial pinnae 3.3–7.6 cm apart, concolorous, light brown to rather dark greenish brown, texture thin to intermediate, rachises not winged; terminal pinnae 8.6–16 × 1.7–4.9 cm, parallel-sided or lanceolate, bases acute, apices 1.7– 3.3 cm long, acuminate, margins of apices entire, sinuate or crenulate; largest lateral pinnae 17–34 × 2.4–5.5 cm, 4.9–8.8 times as long as wide without apex, parallel-sided (or slightly wider at or above middle), pinna apices symmetrical (acute to obtuse) or slightly asymmetrical (obtuse proximally, acute distally), apices 1.4–3.7 cm long, (long-)acuminate, margins of apices entire, sinuate or crenulate (rarely serrulate at shoulder of pinna); veins 15–20 per cm, mostly forked at costa. Largest fertile lateral pinnae 17–19 × c. 2.3 cm, parallel-sided or long-lanceolate, bases acute, symmetrical or slightly asymmetrical, apices 1.0– 1.6 cm long, acuminate to cuneate. Juveniles not known.

Distribution and habitat — Danaea antioquiana is known from the Magdalena River Valley in Colombia (Antioquia and Santander). It has been found in lowland forests at 60–820 m near ravines and rivers. Fig. 3.

Conservation status — We place Danaea antioquiana in the Vulnerable (VU B1ab(iii)+2ab(iii)) category ( IUCN 2012). It has an Extent of occurrence of 8511 km 2 and is known from only five locations, which corresponds to the VU category. Its Area of occupancy of 20 km 2 corresponds to the EN category. Danaea antioquiana was said to be locally abundant in two locations and one of the collections was from inside a protected area (Reserva Río Claro in Colombia). However, the rest of the collection localities are outside protected areas, and the area, extent, and quality of suitable habitats were inferred to be suffering continuing decline from deforestation.

Etymology — The name refers to the Antioquia Department in Colombia, where the type was collected.

Remarks — Danaea antioquiana belongs to the clade within D. subg. Danaea that occurs outside Amazonia and includes true D. nodosa (which is found in Central America and the Greater Antilles) and D. sellowiana (which is found in the Atlantic coastal forests of Brazil and adjacent Paraguay). Although superficially similar, D. nigrescens Jenman (which is found in Amazonia and the Guianas) belongs to a different clade. These four species (and especially the three extra-Amazonian ones) are morphologically hard to distinguish, but genetic evidence shows that they are distinct (details are presented in Keskiniva & al. 2024).

Danaea nigrescens still remains enigmatic. It has not been lectotypified, so we do so here: the lectotype is Jenman 53, Upper Demerara River, Guyana, 1898 ( US 1120090), and the other specimens with the same collecting locality and date information become isolectotypes (Jenman in E00037360 in E and 172 and 173 in NY). The type material is morphologically even more similar to D. nodosa than most material from the Guianas and Amazonia. Unfortunately, we do not have DNA material from the type locality, so the possibility remains that what we here call D. nigrescens actually consists of two species, in which case the genetic affinity of D. nigrescens s.s. would be unknown.

The genetic distance is especially large between Danaea antioquiana and D. nodosa , even though the morphological variation in these two overlaps almost completely. They do not seem to occur in the same geographical area, as D. antioquiana is (so far) known only from the Magdalena River Valley in Colombia. Danaea antioquiana is also morphologically similar to D. sellowiana , from which it differs by generally having more parallel-sided and straight pinnae (vs narrow-elliptic and slightly curved) and drying a more yellowish colour (vs bluish to greyish green). These are difficult and variable characters, however; in practice, this pair can also best be separated with genetics and biogeography.

Danaea antioquiana is also closely related to D. alba , D. longicaudata and D. grandifolia , but these species are relatively easy to tell apart morphologically. This is especially true for D. longicaudata , which is a smaller plant (leaves <1 m vs> 1 m) with an erect trunk (vs creeping dorsiventral rhizome) and smaller lateral pinnae (10–16 cm vs 17–34 cm long, 1.8–2.6 cm vs 2.4–5.5 cm wide) with long-caudate (vs acuminate) apices. Danaea antioquiana differs from D. alba and D. grandifolia in having creeping rhizomes with leaf bases in two rows (vs 3–5 rows in the others), shorter terminal pinnae (8.6–16 cm vs 22–28 cm long in D. alba , 18–24 cm in D. grandifolia ), and more pinna-pairs (11–19 vs 8–9 in D. alba , 8–12 in D. grandifolia ) that are often narrower (minimum 2.4 cm wide vs 4.5 in D. alba , 4.2 in D. grandifolia ), have more densely packed veins (15–20 veins per cm vs 12–13 in D. alba , 11–15 in D. grandifolia ), and often have sinuate or crenulate apices (vs entire in D. alba and entire or slightly sinuate in D. grandifolia ). It also differs from D. grandifolia in acuminate pinna apices (vs usually cuspidate), and from D. alba in having petioles without nodes (vs petioles sometimes with one node), and a thinner pinnae texture and darker colour when dry. Danaea grandifolia is a montane species, occurring at 600–1600 m, whereas D. antioquiana is generally found at lower elevations (60–820 m).

Danaea antioquiana differs from the Lesser Antillean D. kalevala both genetically and in having rhizomes with leaf bases in two rows (vs 3–5 rows) and wider fertile pinnae (6.7–7.6 vs 8.4–9.6 times as long as wide without apex).

Additional specimens examined — COLOMBIA: ANTIOQUIA: Remedios Municipality, Sitio Otu, 3 km from Santa Isabel, Vereda Los Lagos, 11 km S from Remedios, 06°56'N, 74°45'W, 820 m, 1987, Callejas 4705 (NY!); Dos Bocas, on Río Nechi, near Pato, drainage of Río Nechi, 100–200 m, 23–25 Jun 1944, Ewan 15823 (BM!, GH!, US!); Nechi Municipality, Verada Santa Maria, near chapel on edge of Santa Maria ravine, 08°82'N, 74°45'W, 60 m, 4 Mar 2010, Rodriguez 6565 (COL-3!); SANTANDER: Vicinity of Puerto Berio , between Carare and Magdalena Rivers, 100–700 m, 29 Jul 1935, Haught 1841 (COL!, MICH!, S, US!) .