Zamia sinuensis Calonje & J.Castro, 2021

Calonje, Michael, Hernández, Jonatan Castro, Coca, Luis Fernando, Jaramillo, Daniel & Aristizábal, Arturo, 2021, Two new species of Zamia (Zamiaceae, Cycadales) from the Magdalena-Urabá moist forests ecoregion of northern Colombia, Phytotaxa 497 (1), pp. 1-19 : 9-14

Zamia sinuensis Calonje & J.Castro sp. nov. (Figs. 7A–G, 8A–I, 9A–F)

Diagnosis: —The species is similar to Zamia manicata from which it is distinguished in having leaflets that are strongly undulate and lacking a distinct petiolule and gland-like collar at the junction of the lamina and the petiolule.

Type: — COLOMBIA. Córdoba: Municipio de Tierralta, Parque Nacional Natural Paramillo : 187 m, 3 Oct. 2017, J . Castro, D. Taborda & P . Hernández 1146 (holotype HUA!) .

Additional specimens examined (paratypes): — COLOMBIA. Córdoba: Municipio de Tierralta, Parque Nacional Paramillo : 180 m, 3 Oct. 2017, J . Castro, D. Taborda, P . Hernández 1147 ( HUA!).

Description: — Stem hypogeous or semihypogeous, tuberous, solitary or clumping with up to three apices, cylindrical, 10–30 × 5–20 cm. Cataphylls chartaceous, triangular to narrowly triangular, pale tomentum covering from the base, pale brown-colored, losing tomentum and turning dry and brown at maturity, 5.3–14.5 cm long and 2.0–5.0 cm wide at the base. Leaves 3–6 per apex, erect to slightly spreading, 1.8–3.1 m long, 24.1–52.4 cm wide. Petiole 20–175 cm long and 0.7–1.0 cm thick at the middle, entire length strongly to moderately armed with prickles 0.4–3.6 mm long, abruptly swollen base 2–3 cm thick. Rachis 20–135 cm long, lightly armed with prickles in the proximal third. Leaflets

FIGURE. Zamia “Cogollo” in habitat. A. Large plant with Arturo Aristizábal holding two leaves. B. Leaf. C. Median leaflets showing adaxially raised longitudinal crease. D. Immature ovulate strobilus showing elongated sterile apex. Photographs by Arturo Aristizábal.

FIGURE. Vegetative characteristics of Zamia sinuensis . A. Leaflet tip showing dentation. B. Median leaflets illustrating strong undulation, abaxial side. C. Median section of petiole armed with prickles. D. Leaf, abaxial side. E. Cataphyll. F. Apex of new leaf in the process of expansion showing white tomentum. G. Median leaflet (dry). Photographs taken at type locality by Jonatan Castro, illustration by Michael Calonje.

FIGURE. Reproductive characteristics of Zamia sinuensis . A. Pollen strobilus near pollen dehiscence. B. Pollen strobilus with peduncle. C. Microsporophyll shield. D. Microsporophyll adaxial side. E. Microsporophyll abaxial side. F. Ovulate strobilus, fully developed but slightly immature. G. Megasporophyll, abaxial side. H. Megasporophyll shield. I. Close-up of distal half of ovulate strobilus. Photographs taken at type locality by Jonatan Castro, illustration by Michael Calonje.

FIGURE. Zamia sinuensis in habitat. A. Large megasporangiate plant with three apices and three ovulate strobili, with David Taborda for scale. B. Immature and near-mature ovulate strobili. C. Close-up of stem and petiole bases. D. Microsporangiate plant. E. Leaf apex displaying strongly undulate leaflets. F. Pollen strobilus near dehiscence stage. All photographs taken at type locality. Photograph E by David Taborda, all others by Jonatan Castro.

11–54, suboppositely to subalternately arranged, spaced 3.0– 3.5 cm apart at leaf center, articulate insertion on rachis 4.3–6.9 mm wide, chartaceous to subcoriaceous, strongly discolorous, adaxially dark green and lustrous, abaxially light green and dull, new leaflets emerging densely white tomentose, gradually becoming glabrous, lanceolate, symmetrical to slightly falcate, strongly undulate longitudinally, margins revolute and bearing 32–39 marginal teeth 0.6–2.3 mm long restricted to distal half, basal leaflets 24.5–26.2 × 4.2–4.5 cm, middle leaflets 23.5–25.8 × 3.7– 3.9 cm, apical leaflets 17.9–21.6 × 3.1–3.5 cm. Pollen strobili 1–5 per crown, at pollen shedding 4.9–5.1 × 1.0– 1.2 cm, peduncle 23–24 cm long, 0.38–0.40 cm diameter at base, strobilar axis and inner surfaces of microsporophylls glabrous. Microsporophylls spirally arranged in 15 orthostichies of 12–13 fertile sporophylls each, 5.0–5.6 × 5.3–5.4 mm, distal shield encompassing 1/4 to 1/3 of sporophyll length, external face hexagonal relatively flat with rounded edges, cream colored with reddish-brown speckled tomentum, abaxial surface with 14–16 microsporangia aggregated into two separate groups along margins and extending beyond surface of lamina, adaxial surface glabrous and lacking microsporangia. Ovulate strobili typically one per stem apex, 27.5 × 5.0 cm, reddish-brown, cylindrical with elongated sterile apex 170 mm long. Strobilar axes and megasporophyll pedicels glabrous on mature strobili, peduncle 40.0 × 1.5–2.1 cm, dark olive green with fine tan tomentum. Megasporophylls spirally arranged in 8 orthostichies of 13–14 sporophylls each, pedicel 11–14 mm long, sterile shield flat (not extruded), 3–5 mm thick with oblong-hexagonal distal face 15–17 mm tall and 23–24 mm wide and terminal face shallowly depressed. Seeds ovoid to ovoid-pyramidal, at maturity 13.0–14.0 × 7.5–8.5 mm with sarcotesta 1 mm thick, sclerotesta 11.0–12.0 × 6.5–7.5 mm.

Etymology: —The epithet refers to the Sinú River basin in which this species occurs.

Distribution, habitat and climate: — Zamia sinuensis is only known from two simultaneous collections within the same population occurring 3 km distant from each other in disturbed tropical moist forest in the Sinú River basin. The known elevational range is 180– 187 m. The climate within the area of occupancy of Z. sinuensis is classified as tropical monsoon (Am) by the Koppen-Geiger classification system ( Geiger, 1954; Köppen, 1918; Kottek et al., 2006). It is characterized by having monthly mean temperatures above 18 °C and a distinct dry season. The annual mean temperature within its area of occupancy ranges between 25.4° C and 25.5° C, and the annual precipitation ranges between 2200–2900 mm /yr. The rainfall pattern is relatively unimodal, with the dry season occurring December through March, and the rainy season in April through November. The rainiest month is May with 420–430 mm, and the driest month is February, with 56–58 mm.

Ecology: —This species remains poorly understood and understudied due to the logistical difficulties and security concerns impeding long-term access to its habitat. Little is known about its demography, population viability, or biological interactions (e.g. pollination and seed dispersal agents, herbivory, etc.). During our October 2017 visit, we observed pollen strobili at near pollen release, immature and near-mature ovulate strobili, and newly emerging leaves. Additional observations at different times of the year will be necessary to better understand the phenology of this species.

Conservation: —The only known collections of this species are from within a protected area, Paramillo National Park. Nevertheless, the distribution, abundance, demography, and threats facing this species remain unknown, so the species should be considered Data Deficient (DD) in the IUCN Red List until enough information is obtained to adequately assess its risk of extinction.

Morphological and taxonomic affinities: — Zamia sinuensis most closely resembles Z. manicata but the species can readily be distinguished from each other based on several qualitative morphological characters (Table 2). Zamia sinuensis is readily distinguished from Z. manicata by its strongly undulate leaflets lacking a petiolule and gland-like collar at the base. It is separated from populations of Z. manicata by the Serranía de Abibe, a northward extension of the Andean Cordillera Occidental, but it shares the Sinú River basin with Z. restrepoi and occurs only 20 km distant from historic collections of this species. However, the two species do not resemble each other at all vegetatively (Fig. 1) and do not appear to be sympatric.