Danaea elongata Keskiniva & Tuomisto, 2024

Keskiniva, Venni & Tuomisto, Hanna, 2024, Danaea (Marattiaceae) keeps diversifying, part 1: eighteen new species, Willdenowia 53 (3), pp. 173-228 : 194-197

7. Danaea elongata Keskiniva & Tuomisto , sp. nov. (D. subg. Danaea ) – Fig. 16 .

Holotype: Ecuador, Zamora-Chinchipe, Bombuscaro, Podocarpus National Park , 950–1050 m, 16 Sep 2004, Lehnert 1258 ( QCA! (mounted on 2 sheets: 208044 & 7008041); isotypes: GOET! (042667), TUR!, UC! (mounted on 2 sheets: 1794279, 1794280)) .

Diagnosis — Similar to Danaea nigrescens Jenman , but differing in pinna apices usually without serrations (vs almost always serrate); medial pinnae parallel-sided (vs usually oblanceolate); pinnae generally narrower (to 4.3 cm vs to 5.7 cm wide, 4.9–7.6 vs 4.1–6.7 times as long as wide without apex); genetically differs in locations 105 (G vs T), 377 (C vs T), 446 (T vs C), 480 (C vs A), 614 (G vs A), 620 (T vs C), 1004 (C vs T), 1019 (T vs A) of atpB reference sequence; 698 (T vs C), 752 (G vs A), 1191 (T vs C) of rbcL reference sequence; 48 (T vs C), 71 (T vs C), 112 (G vs T), 213 (A vs C), 293 (G vs A), 299 (G vs A), 320 (T vs G), 742–744 (TTT vs gap), 762–763 (CC vs gap), 858 (G vs A) 876 (C vs gap), 886–889 (TAAA vs gap) of trnL-F reference sequence; 109 (A vs G), 334 (A vs C), 424 (T vs C), 471 (C vs T), 517 (C vs T), 617 (C vs A), 630 (A vs G), 642 (G vs A), 643 (A vs G), 650 (T vs C), 670 (G vs A), 673 (A vs G), 684 (A vs C), 688 (T vs C), 690 (T vs gap), 877 (C vs T), 909 (T vs C), 958 (T vs C) of rpl32 reference sequence. Similar to D. erecta Tuomisto & R. C. Moran , but differing in creeping, dorsiventral rhizomes (vs erect, radial), and sometimes having serrations in pinna apices (vs never serrate). It is unique in D. subg. Danaea by having a T (vs A or C) at position 650 of rpl32 reference sequence and a T (vs C) at position 1191 of rbcL reference sequence.

Description — Rhizomes creeping, dorsiventral, leaf bases in two rows, 3.0–4.0 cm in diam., to at least 15 cm long. Sterile leaves 92– 200 cm long; petioles 55–92 cm long, lacking nodes, not winged; laminae 60–69 × 45–70 cm, obovate, imparipinnate, 9–15 pinna-pairs, medial pinnae 3.5–5.0 cm apart, slightly paler abaxially than shiny green adaxial side when fresh, dries green (or brown in alcohol), texture relatively thin to intermediately thick, pinna margins sometimes slightly cartilaginous, rachises not winged; terminal pinnae 16–26 × 1.8–5.2 cm, oblong (to lanceolate), bases acute, apices 2.0–4.0 cm long, long-acuminate to caudate, margins of apices entire, sinuate or serrulate; largest lateral pinnae 22–34 × 3.9–4.3 cm, 4.9–7.6 times as long as wide without apex, parallelsided (to slightly wider above middle), bases symmetrical, acute to obtuse, apices 2.5–3.6 cm long, acuminate to long-caudate, margins of apices entire, sinuate, serrulate or serrate; veins 13–19 per cm, mostly forked at costae, some simple. Fertile pinnae 14–22 × 1.9–2.1 cm, parallel-sided or long-elliptic, bases symmetrical, acute to obtuse, apices 0.5–2.0 cm long, acuminate to cuneate, margins of apices entire to crenulate. Juveniles not known.

Distribution and habitat — Grows at mid-elevations, 550–1300 m, on the Amazonian side of the Andes in Ecuador (Zamora-Chinchipe) and Bolivia (Cochabamba, El Beni, La Paz); it may occur in between as well, but we have no confirmed records from Peru. Found in (pre) humid, evergreen montane forests and lower montane forests. Individual labels mention collections made in a ravine, in disturbed vegetation, in a coffee plantation, and on sandstone. Fig. 17 .

Conservation status — We place Danaea elongata in the Least Concern (LC) category ( IUCN 2012). It has a known Area of occupancy of 36 km 2, which corresponds to the EN category, and an Extent of occurrence of 173,189 km 2, which corresponds to the LC category. Whether the lack of records from Peru indicates lack of collecting activity or actual fragmentation of the species into two distant populations is unknown. Danaea elongata is known from only 10 collections, but all of these are from inside national parks (Parque Nacional Tibnis and Isiboro Sécure National Park and Indigenous Territory in Bolivia and Podocarpus National Park in Ecuador). There appears to be no imminent threat to all its subpopulations.

Etymology — Named for the long, narrow, parallel-sided pinnae.

Remarks — Danaea elongata is a rather large species with a disjunct distribution in the Ecuadorian and Bolivian Andes. It differs from the typical D. nigrescens in usually having entire to sinuate pinna apices (vs usually serrate) and parallel-sided medial pinnae (vs usually oblanceolate) that are generally narrower (to 4.3 cm vs to 5.7 cm wide, 5–8 vs 4–7 times as long as wide without apex). Danaea nigrescens usually grows at lower elevations (50–900 m vs 550–1300 m) and has a wide distribution in the Amazonian lowlands (vs found only in the foothills of the Andes). However, there is both geographical and morphological overlap, and some specimens can be reliably identified only with DNA.

The most reliable morphological difference between Danaea elongata and D. erecta is in rhizome habit (creeping and dorsiventral vs erect and radial). In addition, sometimes D. elongata has serrations at the pinna apices (vs margins always entire), and it usually grows at lower elevations (550–1300 m vs 500–2000 m) and only on the Amazonian side of the Andes (vs on both sides). However, reliable identification generally requires either information on rhizome habit or DNA.

Danaea elongata differs from D. kessleri in having generally more pinnae (9–15 vs 4–14) that are usually narrower (max. 4.3 cm vs max. 7.1 cm wide, medial pinnae 4.9–7.6 vs 3.6–7.0 times as long as wide without apex) and parallel-sided (vs often elliptic or oblanceolate), pinna apices that are usually long-acuminate (vs acute to acuminate) and can be serrate (vs always entire), and a terminal pinna that is smaller than second pinnae distally (vs usually largest or larger than second pinnae distally). In addition, D. elongata dries brown in alcohol (vs green), grows at higher elevations (550–1300 m vs 200–800 m), and has a more southern general distribution ( Fig. 17 ).

Danaea elongata is a smaller plant than D. cartilaginea Christenh. & Tuomisto (sterile leaves to 2 m vs to 3 m long), with smaller and especially narrower pinnae (largest lateral pinnae 22–34 × 3.9–4.3 cm vs 27–49 × 4.6–10 cm). The pinnae of D. elongata are thinner in texture and do not have the thick cartilaginous margins usually present in D. cartilaginea . Both species can rarely have apices that are serrate throughout, but more typically D. cartilaginea has entire pinna apices with the ends of the veins protruding, whereas D. elongata has apices that are entire, sinuate or serrate only at the shoulder of the pinnae. In addition, D. elongata usually has more pinna-pairs (9–15 vs 4–10), a terminal pinna that is usually smaller than second pinnae distally (vs often larger than second pinnae distally), and lateral pinnae that are parallel-sided or seldom oblanceolate (vs seldom parallel-sided, usually elliptic or oblanceolate).

Danaea elongata is genetically clearly different from D. nodosa , but morphologically the two overlap almost completely and are very hard to distinguish without DNA analysis. Luckily for botanists, they do not occur in the same geographical area, as D. elongata is restricted to the Amazonian side of the Andes whereas D. nodosa is found in Central America and the Greater Antilles.

Additional specimens examined — BOLIVIA: COCHABAMBA: Prov. Chapare, Villa Tunari 34 km toward Cochabamba Trail on bank of Río Espíritu Santo, 670 m, 1905, Beck 7357 (F!, Z!). Prov. Ayopaya, crossing Rio Ipiri in serrania de Mosetenes, 16°03'S, 66°40'W, 610 m, 27 Sep 2004, Huaylla 1456 (GOET!, UC!); Territorio Indígena Parque Nacional Isiboro-Secure, cordillera de Mosetenez, laguna Carachupa, 16°14'S, 66°25'W, 1300 m, 2003, Kessler 13000 (GOET!, TUR!); EL BENI: Prov. Gral. Ballivian, km 16 on camino maderero to SW of km 12 Yucumo-Rurrenabaque, 15°05'S, 67°07'W, 700 m, 31 Jul 1997, Kessler 10901 (GOET-2!, LPB, UC!); LA PAZ: Prov. Caranavi, serranía Bella Vista, 36 km from Caranavi toward Sapecho, 15°41'S, 67°30'W, 1300 m, 22 Aug 1997, Kessler 11238 (GOET, UC!); Sapecho; Colonia Tupiza B, c. 3 h walk to Sapecho, 15°31'S, 67°18'W, 950 m, 14 Apr 2003, Lehnert 769 (GOET!). — ECUADOR: ZAMORA-CHINCHIPE: Lodge “Copalinga”, 3 km from Bombuscaro Ranger Station of Podocarpus National Park, 900–1300 m, 15 Sep 2004, Lehnert 1244 (GOET!, TUR!, QCA!, UC!); Campamento Shaime (Shaimi) along Rio Nangaritza. Trail to oil bird cave (“cueva de los tayos”), 04°19'S, 78°40'W, 950–1050 m, 6 Nov 2004, Lehnert 1523 (GOET!, TUR!, QCA!, UC-2!); Parque National Podocarpus, Bombuscaro, MATRIX plot L5, along train “Higuerones”, 04°07'S, 78°59'W, 1050 m, 20 Nov 2010, Lehnert 2074 (QCA!, STU-2!), VT!).

Figures

Fig. 16. Danaea elongata: A: medial pinna apex (typical); B: medial pinna apex (serrate form); C: fragment of creeping rhizome; D: sterile leaf apex; E: sterile leaf medial pinnae; F: fertile pinna. – A, D, E: Lehnert 1258 (TUR); B: Kessler 13000 (LPB); C: Beck 7357 (F); F: Lehnert 1523 (UC). – Drawn by Venni Keskiniva.

Fig. 17. Distribution of types and paratypes of Danaea elongata and D. kessleri.