taxonID	type	description	language	source
03DEFD71E42E2650AE9AA4DEFA87FBF6.taxon	materials_examined	Type: — MEXICO. Campeche: “ Crescit in litore Mexicano, prope Campeche ”, Humboldt & Bonpland s. n. (Lectotype, here designated: P-P 00670906!).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42E2650AE9AA4DEFA87FBF6.taxon	discussion	Notes: — Stevens (2005 b) proposed as lectotype the plate that accompanies the protologue (Humb., Bonpl. Kunth, Nov. Gen. Sp. 1819; Fig. 2 a). However, there is a specimen at P that is part of the original material (Figure 2 A), which has priority over and supersedes the lectotype proposed by Stevens. The P specimen bears the annotation TYPE, a label with the legend “ 4 Gonolobus barbatus, Campeche ”. It also has the customary label identifying the collections of the H. B. K. team (“ Herb. Mus. Paris. HERBIER HUMBOLDT & BONPLAND, AMERIQUE EQUATORIALE ”. In the protologue, the species is identified as “ 4. Gonolobus barbatus ” and it states “ Crescit in litore Mexicano, prope Campeche? ” Furthermore, plate XXCCCIX apparently depicts one of the three stems in this P specimen. However, the protologue of the species does not say where the type was deposited, and it is impossible to say if duplicates were (or still are) present anywhere else. Distribution of duplicates may have happened post 1818 and therefore the material examined by Kunth might have been more extensive. Thus, we have decided to designate this specimen as lectotype.	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42E2650AE9AA4DEFA87FBF6.taxon	distribution	Gonolobus barbatus is locally common and widespread from Veracruz and the drier portions of the Yucatan Peninsula on the Atlantic slope and on the dry forests of Megamexico from Oaxaca and Chiapas south to Nicaragua and also in neighboring Guanacaste in NW Costa Rica. It is the only Gonolobus in the YPBP that routinely occurs in strongly seasonal, disturbed tropical dry forests and even into urban areas. The species is easily diagnosed by its conspicuously barbate petals (Figs. 1 B, 2 A, 3 A).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42E2650AE9AA4DEFA87FBF6.taxon	materials_examined	Specimens examined: — MEXICO. Campeche: Campeche, Edzná, en las ruinas, approx. 18 ° 34 ’ N, 90 ° 14 ’ W, 8 m, 11 August 1983, E. Góngora 1090 (CICY, MEXU); Palmas, Cd. de Campeche, 19 ° 52 ’ 10 ” N, 90 ° 30 ’ W, 7 September 1998, C. Gutiérrez B. 5933 (MEXU, UCAM); 2 km noroeste de Chiná, 19 ° 45 ’ N, 90 ° 31 ’ W, 8 m, 13 September 1999, C. Gutiérrez B. 6680 (MEXU, UCAM); Zona Arqueológica de Edzná, 19 ° 35 ’ 49 ” N, 90 ° 13 ’ 52 ” W, 11 August 1983, A. Puch T. 1289 (CICY, MEXU, XAL); Unidad de evaluación y Monitoreo de la Biodiversidad de Hampolol, 19 ° 56 ’ 30 ” N, 90 ° 22 ’ 40 ” W, 24 April 1996, P. Zamora & D. Méndez D. 4999 (CICY, UCAM). Quintana Roo: Mun. F. Carrillo Puerto, X-Hazil, a orilla de carretera Chetumal-Felipe Carrillo Puerto en km 107, 19 ° 21 ’ 51 ” N, 88 ° 4 ’ 6 ” W, 10 – 15 m, 6 August 2001, P. Macario & L. Sánchez 576 (CICY, CIQR). Yucatán: Mun. Celestún, a 10.2 km al N del hotel Ecoparaíso, 21 ° 0 ’ 59 ” N, 90 ° 19 ’ 36 ” W, 14 July 2010, M. Ferrer, A. Dorantes, F. Chi & C. Pérez 178 (CICY); 5 km al N del hotel Ecoparaíso, 20 ° 58 ’ 39 ” N, 90 ° 21 ’ 23 ” W, 8 July 2010, M. Ferrer, A. Dorantes, F. Chi & C. Pérez 155 (CICY); 6 km al N del centro del puerto de Celestún, 20 ° 54 ’ 48 ” N, 90 ° 22 ’ 55 ” W, 24 June 2010, M. Ferrer, A. Dorantes, F. Chi & C. Pérez 97 (CICY); Mun. Chankom, Chankom, Casa del Sr. Mariano Caamal, 20 ° 32 ’ N, 88 ° 31 ’ W, 20 m, 2 March 1981, E. Ucán Ek 712 (XAL); Mun. Izamal, Izamal, 20 ° 55 ’ 48 ” N, 89 ° 00 ’ 36 ” W, 10 – 20 m, 1985, G. F. Gaumer 15699 (WIS); G. F. Gaumer 803 (BM, CAS, EAP, F, GH, K, MO, NY, P, WIS); Chiceh, 20 ° 54 ’ N, 88 ° 58 ’ 12 ” W, August 1916, G. F. Gaumer & et al. 23403 (F, G, GH, MO); Mun. Mérida, Jardín Botánico Regional [Roger Orellana], approx. 21 ° 1 ’ 30 ” N, 89 ° 38 ’ 30 ” W, 10 m, 17 September 1998, P. Simá 2243 (CICY, F, MEXU, MO); 8 December 1995, J. C. Trejo 537 (CICY); Sector NW de la Ciudad de Mérida, Colonia Montealbán, ca. 1.5 km al sur del Periférico, 21 ° 1 ’ 20 ” N, 89 ° 36 ’ 10 ” W, 24 September 2001, G. Carnevali 6414 (CICY, MEXU, MO); 18 August 2003, R. Duno de Stefano & G. Carnevali 1659 (CICY, MO); Mérida, Cordemex, Jardín Botánico Regional [Roger Orellana], 21 ° 1 ’ 30 ” N, 89 ° 38 ’ 30 ” W, 10 m, 17 September 1996, G. Carnevali, R. Durán García & P. Simá 4274 (CICY, MO); Mun. Muna, near Muna in second growth, approx. 20 ° 29 ’ 5 ” N, 89 ° 42 ’ 47 ” W, May-August 1938, C. L. Lundell & A. A. Lundell 8160 (CAS, F, LL, MEXU, MICH); Dzityá, 16 August 2021, G. Carnevali 8584 (CICY); Mun. Oxkutzcab, Xul, 20 ° 6 ’ 8 ” N, 89 ° 27 ’ 36 ” W, 60 m, 28 September 1983, O. L. Sanabria & P. Simá 286 (CICY, MEXU, XAL); Mun. Santa Elena, Uxmal, Misión Uxmal Hotel, 21 ° 06 ’ 00 ” N, 87 ° 54 ’ W, 30 September 1982, S. P. Darwin 2355 (CICY, MEXU, MO, NO, NY); Hacienda Uxmal, 20 ° 22 ’ N, 89 ° 44 ’ W, 29 August 1981, M. Narváez S. & A. Puch T. 681 (CICY, XAL); vicinity of Sayil, 20 ° 10 ’ 48 ” N, 89 ° 39 ’ W, 69 m, 6 January 1982, S. P. Darwin, E. Sundell & D. A. White 2165 (MO, NO); Mun. San Felipe, 1 km al norte del rancho “ Chinalco ”, reserva ecológica de Dzilam, 21 ° 31 ’ N, 88 ° 17 ’ W, 3 m, 28 September 1991, J. C. Tun 367 (MEXU, UADY); Mun. [Tinúm], camino a las grutas de Balancanché, 20 ° 39 ’ 30 ” N, 88 ° 32 ’ 15 ” W, 8 m, 7 September 1983, C. Chan V. 2900 (CICY, XAL); Mun. Tizimín, en el ejido del Santa Clara el cual se encuentra a 38 km de Tizimín, approx. 21 ° 22 ’ 20 ” N, 88 ° 3 ’ 56 ” W, 27 August 1986, J. A. Aguilar Z. & S. Diez Martínez y Day 365 (MEXU); Mun. Ucú, 7 km al W de Sierra Papacal, 400 m antes de la curva hacia Chuburná Puerto, 21 ° 8 ’ 20 ” N, 89 ° 47 ’ 30 ” W, 5 m, 26 November 1988, F. Tun, J. A. González-Iturbe & I. Olmsted 407 (CICY, MEXU).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42F2658AE9AA420FDA9FECB.taxon	discussion	A species of Gonolobus phenetically similar and probably related to G. erianthus Decaisne (1844: 592), a taxon that grows at higher elevations of (200 –) 900 – 1300 (– 1600) m in central Mexico south to Nicaragua in cloud forests, whereas the new species grows in lowland, seasonally dry forests at 10 – 100 m. Furthermore, G. caamalii has oblong to oblong elliptic, narrower (3.0 – 3.2 times longer than wide) corolla lobes whereas they are proportionally wider (1.7 – 1.9 times longer than wide) in G. erianthus. Live flowers have strikingly different color patterns as G. caamalii has dark yellow green corolla lobes with a dark purple (almost black) longitudinal, callose band along the proximal 2 / 3 on the right side of the lobes whereas this band is absent or pale yellow, slightly evident in G. erianthus. The new species exhibits a 1.1 – 1.3 mm broad, annular, continuous dark purple-black band, the faucal annulus, surrounding the gynostemium and corona at the base of the corolla lobes. This band is narrower and either absent or pale green in G. erianthus.	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42F2658AE9AA420FDA9FECB.taxon	materials_examined	Type: — MEXICO. Yucatán: Mun. Valladolid, 680 – 700 m al E del poblado de Chan Yokdzonot 2, unos 1380 – 1400 m al este del desvío Valladolid-Chan Yokdzonot, unos 3.7 – 4 km al norte en línea recta de Valladolid, 20 ° 44 ’ 15.34 ” N, 88 ° 11 ’ 23.46 ” W, 25 m, 24 November 2020; selva mediana subcaducifolia muy húmeda en esta época del año, G. Carnevali, R. Duno & M. A. Caamal Dzul 8573 (Holotype, CICY; isotypes, GH, MEXU, MO).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42F2658AE9AA420FDA9FECB.taxon	description	Herbaceous perennial vines, growth more of less monopodial, rarely branching. Latex white. Stems pubescent, with short and long, pale brown yellow, retrorsely spreading hairs up to 0.5 mm long, glandular capitate trichomes absent, pubescence dense throughout, not arranged in lines, denser distally and at the internodes, nodes densely pubescent, internodal colleters 3, 0.1 mm long. Leaf blades ovate, elliptic-ovate to oblong-ovate, 5.5 – 8.5 (– 11.6) × (3.0 –) 3.5 – 6.0 (– 7.3) cm, apex acute to abruptly acuminate, acumen narrowly obtuse, 1.5 – 2.1 cm, bases always deeply cordate, lobes (0.7 –) 1.0 – 1.2 (– 1.5) cm long, convergent or more rarely somewhat parallel, often overlapping, sinus 1.0 – 1.5 cm, adaxial surface very sparsely strigose, glandular capitate trichomes absent, eglandular trichomes scattered along the major and minor veins, margins entire with glandular capitate, hairs, 0.3 mm long, colleters 5, borne on each side of the petiole base, two in the base, two distal, and one in the apical, the basal one 0.5 mm long, the smaller one 0.1 mm long, eventually deciduous, abaxial surface paler than the adaxial surface, laxly pubescent throughout, nerving of 5 – 6 pairs of primary, the proximal retrorse and innerving the basal lobe, the rest at a 45 ° degree to the midnerve, not reaching the margin, nerves raised with a line of hairs; petioles (3.5 –) 4.0 – 5.5 cm long, densely strigose with very short hairs throughout, more dense distally, becoming glabrescent proximally, glandular capitate trichomes absent; stipular colleters 2 (– 4), ca. 0.3 mm long, 1 - 2 borne on each side of the petiole base. Inflorescence subcapituliform, 1 – 3 (– 5) - flowered, the distal flowers maturing first; peduncles (1.5 –) 1.7 – 2.0 cm long, indument as on the stems but hairs shorter; rachis very short, 0.3 – 0.5 cm; pedicels 2.5 – 2.7 (– 3) cm long, indument as in the peduncle; floral bracts ca. 3 × 0.4 mm, eventually deciduous, pubescent as in the peduncles on both surfaces. Flowers showy, flat, presented vertically. Calyx lobes 5, 10 – 11 × 3 – 4 mm, ovate- elliptic to triangular elliptic, abruptly acuminate, margins pubescent, both surfaces strigose throughout, margin with longer hairs, glandular capitate trichomes absent, colleters 1 - 2 per sinus. Corolla 5 - lobed, lobes green or yellowish green, with slightly darker, inconspicuous, reticulate nerving, and a dark-purple to almost black longitudinal, callose band along the proximal 2 / 3 on the right side of the lobes, the apex of the corolla lobes tinged in the same hue, the base of the corolla, surrounding the corona and the gynostemium, provided with a 1.1 – 1.3 mm broad, annular, continuous dark purple-black band of irregular width but wider opposite the anthers, strigose proximally with 0.02 mm long hairs; corolla lobes oblong-triangular to oblong, acute to narrowly acute, lobes 15 – 18 × 4.7 – 6 mm, wider proximally (5.8 – 6.0 mm wide), dextrogyrous at the distal half forming an angle of 30 – 35 ° to the general axis of the flower, lobes slightly overlapping proximally, glandular swelling absent in the sinus; adaxial surface glabrescent but densely hairy on the dark band, the pubescence mostly of eglandular trichomes to 0.4 – 0.9 mm long, abaxial surface moderately pubescent with eglandular trichomes 1.0 mm long, but conspicuously more pubescent near the apex, glabrescent on the underside of the callose, dark-colored band. Faucal annulus a distinctly raised ridge opposite each corolla lobe sinus, inconspicuously 5 - lobed, 0.5 – 0.6 mm tall, with upper margins strigose with 1.2 mm long hairs. Gynostegial corona of fused staminal (Cs) and interstaminal parts, single, 5 - lobed, 5 mm diameter, adnate to the ring, corona lobes 2 × 1.2 mm, pale green yellow, subquadrate reniform, somewhat bowl shaped, fleshy, smooth; gynostegium with stipe 2.5 mm high × 1.2 mm diameter, 5 - winged, each wing with a small, fleshy projection distally; dorsal anther appendages 1.6 – 1.8 × 2.2 – 2.3 mm, deflexed, reniform-subquadrangular, wider proximally, shallowly bilobed at apex, thinly fleshy, concave, shiny wine-red; style head 3.2 – 3.8 mm wide, terminal appendages appressed to margin of style apex, guide rails + / - indistinct, 0.2 – 0.3 mm. Pollinarium with an ovoid corpusculum, 0.35 – 0.36 x 0.05 – 0.36 mm, dark brown, caudicle 0.5 – 0.6 × 0.3.0 - 0.31 mm, flat, pollinia 1.6 – 1.7 x 0.6 – 0.7 mm, ovoid-ellipsoid apically rounded, translucent proximally, somewhat excavated ellipsoid, complanate. Follicles known only from a photograph, ovoid, sharply 5 - winged, peduncles recurved.	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42F2658AE9AA420FDA9FECB.taxon	materials_examined	Paratypes: — MEXICO. Yucatán: Mun. Abalá: 15 km al S del poblado de Yaxcopoil, a lo largo de la carretera Mérida-Muna, 20 ° 36 ’ 30 ” N, 89 ° 42 ’ 50 ” W (correctly 20 ° 36 ’ 35.93 ” N, 89 ° 42 ’ 52.60 ” W), approx. 12 m, “ selva baja caducifolia, aguada o cenote de unos 200 m de diámetro; trepadora herbácea, rara localmente; látex blanco; flores verdes ”, 7 November 2001, G. Carnevali, J. L. Tapia & F. May & M. Gómez 6438 (CICY); same locality, cultivated at Jardín Botánico Regional Roger Orellana, at the Centro de Investigación Científica de Yucatán, flowering 15 July 2015, G. Carnevali 8579 (CICY, spirits). Mun. Oxkcutzcab, Helen Moyers Biocultural Reserve at Rancho Kiuic (Kaxil Kiuic), approx. 20 ° 5.79 ’ N, 89 ° 33.06 ’ W, [90 – 100 m], “ on the trail to Santa Rita, near the first haltun. Herbaceous liana; corolla green, contorted; gynostegium deep maroon ”, 20 October 2005, W. J. Hayden 4923 (URV). Mun. Tinum: Rancho San Pedro, 20 ° 47´N, 88 ° 23 ’ W, 22 m, 24 November 1980 “ flor verde negra ”, E. Ucán Ek 569 (CICY, XAL). Mun. Valladolid, same locality as type, 28 August 2020, G. Carnevali, R. Duno & M. A. Caamal Dzul 8550 (CICY, SEL).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42F2658AE9AA420FDA9FECB.taxon	conservation	IUCN Conservation assessment: — EN. Gonolobus caamalii meets criterion B 1 a, b (i, ii, iii, iv) for a Vulnerable species (V) and B 2 a, b (i, ii, iii. iv) for Endangered species (EN). It is known from only four localities all in the state of Yucatán; its extent of occurrence is of 5,324.757 km 2, and the area of occupancy is of 16.0 km 2. EN B 2 ab (i, ii, iii. iv).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42F2658AE9AA420FDA9FECB.taxon	discussion	Apparently, Gonolobus caamalii is an extremely rare species, having been found only four times at four different localities. At the type locality in northern Yucatán, we were able to record about 20 individuals on a dirt road along a span of 3 – 4 kilometers. Only a few specimens were in flower at any given time during the two visits we made at the locality. This population is severely threatened because of the imminent urban expansion of Valladolid, a medium sized city that is about 4 km south, and which is growing fast. The population SW of Abalá is severely threatened because of the expansion of cattle pastures and it is expected to disappear in the near future. The same applies to the Tinum locality. The population at the Helen Moyers Biocultural Reserve at Rancho Kiuic is protected and it is at this locality where the best survival expectations for the species are met. Because the species is rare, both its EOO and AOO are small, only occurs naturally in nearly undisturbed vegetation, and most of its known populations occur in areas where the original vegetation is currently being or is likely to be substituted by anthropogenic ecosystems during the next few years, we propose the species to be treated as Endangered (EN).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42F2658AE9AA420FDA9FECB.taxon	etymology	Eponymy: Named after Miguel Ángel Caamal Dzul, of Chan Yokdzonot 2, Yucatán, who collected for the second time this interesting species. He has a keen eye for rare plants and enthusiastically collects, cultivates, and photographs the native flora.	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E42F2658AE9AA420FDA9FECB.taxon	discussion	Notes: — Gonolobus caamalii is similar and putatively related to G. erianthus, yet both taxa are amply different in several relevant aspects. Both species have green corollas with reticulate nerving of relatively similar shapes and with one of the margins crenulate, a yellow corona, and reddish anther appendages. However, our new taxon is a lowland species occurring at elevations of 10 – 100 m in tropical dry forests whereas G. erianthus grows at higher elevations of (200 –) 900 – 1300 (– 1600) m in central Mexico south to Nicaragua in tropical humid to cloud forests. The corollas of both species, albeit relatively similar, are readily diagnosed. In G. caamalii, the corolla lobes are asymmetrically oblong to oblong elliptic, 15 – 18 × 4.7 – 6 mm and relatively narrow (3.0 – 3.2 times longer than wide). On the other hand, G. erianthus features asymmetrically elliptic corolla lobes 15 – 23 × 9 – 12 mm that are proportionally wider (1.67 – 1.9 times longer than wide). Moreover, the color patterns of live flowers (even somewhat noticeable in pressed material) are unmistakable. Gonolobus caamalii has dark yellow green corolla lobes that feature a dark purple (almost black) longitudinal, callose band along the proximal 2 / 3 on the right side of the lobes; this band is absent, or it is yellow and only slightly evident in G. erianthus. In addition, there is 1.1 – 1.3 mm broad, annular, continuous dark purpleblack band surrounding the gynostemium and corona at the base of the corolla lobes. This band is narrower and either absent or dark green in G. erianthus. Gonolobus caamalii is fairly distinctive in possessing a very dark, almost black brownish purple, callose longitudinal band parallel to the right margin of the petals and in the fact that the petals are sharply tilted dextrogyrously forming an angle of 30 – 35 ° to the general axis of the flower. In Stevens (2010) useful key to the Mesoamerican Gonolobus, G. caamalii would key out to couplet 36 b because of its abaxially moderately pubescent corolla of 15 – 18 mm long, its uniformly pubescent internodes, and the anther appendages lacking 2 distinct lobes or “ arms ”. Then, it would key out to G. erianthus in couplet 37 a. However, G. caamalii is sharply distinct from G. erianthus (a species ranging widely from Nuevo León and Nayarit, Mexico, to Nicaragua) in several respects as discussed above. In the YPBP, it is difficult to confuse it with any other species. The species is known only from a narrow, arch-like band of seasonally dry forests under Ax (Wo) climate according to the Köppen system (as modified by García, 2004). Here, rains occur mostly in the summer and precipitation is in the 1000 – 1200 mm range. The vegetation is locally called “ selva mediana subcaducifolia ” (“ medium height semideciduous forest ”) and is structurally dominated by several species of woody deciduous species such as Jatropha gaumeri Greenman (1907: 256), Margaritaria nobilis Linnaeus (1781: 428) (Euphorbiaceae), Bursera simaruba (Linnaeus 1753 a: 1026) Sargent (1890: 260) (Burseraceae), Leucaena leucocephala (Lamarck 1783: 12) de Wit (1961: 54) subsp. leucocephala, Caesalpinia gaumeri Greenman (1912: 330), Bauhinia ungulata Linnaeus (1753 b: 374), Gliricidia maculata (Kunth 1823: 393) Kunth ex Walpers (1842: 679) (Fabaceae), Cedrela odorata Linnaeus (1759: 940) (Meliaceae), Ceiba aesculifolia (Kunth 1821: 298) Britten & Baker (1896: 175), Hampea trilobata Standley (1923: 787) (Malvaceae), and Gymnopodium floribundum Rolfe (1901: t. 2699) (Polygonaceae). The area is particularly rich in scandent members of the Apocynaceae with species such as Matelea stenosepala Lundell (1942: 398), Dictyanthus yucatanensis Standley (1930: 37), Cynanchum rensonii Woodson (1941 a: 210), Macroscepis diademata (Ker Gawl. in Edwards 1817: 3, t. 252) Stevens (1983: 405), Echites yucatanensis Millspaugh ex Standley (1930: 35), and Mandevilla subsagittata (Ruiz & Pavón 1799: 19) Woodson (1932: 60 - 70). Herbs on the forest floor include Agave petskinil (Orellana et al., in Hernández et al. 2008: 173) Thiede (2012: 94) (Asparagaceae), Oeceoclades maculata (Lindley 1821: pl. 15) Lindley (1833: 237), Sarcoglottis sceptrodes (Reichenbach f. 1855: 214) Schlechter (1920: 421) (Orchidaceae), and Hybanthus thiemei (Donnell Smith 1905: 1) Morton (1944: 81) (Violaceae). The northern portion of the YPBP seems to be a center of endemism for the Gonolobinae with at least 10 species restricted to this area, including Gonolobus caamalii and the recently described Matelea falcata Juárez-Jaimes et al. (2021: 113). It seems likely that several other novelties are yet to be discovered in this area. Most of these endemic Gonolobinae consist of small populations, most likely threatened, surviving in remnants of the once extensive semideciduous forests that covered the Yucatan Peninsula before pervasive “ slash and burn ” agriculture removed most of them. Gonolobus stenanthus subsp. yucatanensis has been collected near and at the type locality of G. caamalii. For example, G. Carnevali et al. 8377 (CICY, CHIP, CIQR, F, FCME, G, GH, MEXU, MO, SEL, UADY, UCAM, UJAT, XAL; Fig. 3 I) was collected less than 4.5 km to the NW whereas C. L. Lundell & A. A. Lundell 7577 (GH, MEXU, MICH) was collected 41 km E of the type collection of G. caamalii. More recently, M. A. Caamal 01 (CICY; Fig. 3 H) was collected a few hundred meters for the type locality. Thus, it is evident that both species are sympatric or parapatric in the area. However, there is no morphological evidence of gene flow between the two very distinct Gonolobus species. Aside from possible morphological or genetic barriers to gene flow between both taxa, G. stenanthus subsp. yucatanensis flowers at the end of the dry season or beginning of the rainy season (April-July) whereas G. caamalii, at least under natural conditions, blooms toward the end of the rainy season (October-November) providing an additional prezygotic barrier to gene exchange.	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E427265BAE9AA164FE31FD7B.taxon	materials_examined	Type: — Belize, Toledo: “ a low climber in thicket, Toledo, 5 April 1907 ”, M. E. Peck 821 (Holotype, GH!; isotype K, n. v.).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E427265BAE9AA164FE31FD7B.taxon	discussion	Notes: — This species is widespread in the YPBP, usually in flooded areas and mangrove associations. Outside of the YPBP, it has been collected in Veracruz, Tabasco, Chiapas, Guatemala, Belize, and northern Honduras. The species is easily diagnosed in by its extremely narrow corolla lobes with a longitudinal line of trichomes 0.2 – 0.5 mm long along its right margin. The sinus of the leaf base is relatively shallow and broad, which makes it distinctive even vegetatively (Figs. 1 B, 3 B).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E427265BAE9AA164FE31FD7B.taxon	materials_examined	Specimens examined: — MEXICO. Campeche: Mun. Calakmul, a 7.9 km al N del poblado Bel-ha, 18 ° 59 ’ 49 ” N, 89 ° 17 ’ 57 ” W, 136 m, 7 July 2003, D. Álvarez 5964 (MEXU); a 1.6 km al NO de Dos Naciones, 17 ° 59 ’ 3 ” N, 89 ° 21 ’ 41 ” W, 205 m, 12 August 2003, D. Álvarez 6187 (MEXU); 5 km al S de Constitución, a 70 km al E de Escárcega, approx. 18 ° 36 ’ N, 90 ° 8 ’ 11 ” W, 10 July 1983, E. Cabrera & O. Canul 5072 (MEXU); a 55 km al N de Xpujil, 18 ° 59 ’ 46.8 ” N, 89 ° 18 ’ 1.4 ” W, 147 m, 22 August 2002, D. Álvarez, C. H. Ramos, E. Martínez S. & J. P. Abascal 1983 (MEXU); a 2 km al E del poblado “ Unión 20 de Junio ” camino a Flores Magón, 18 ° 48 ’ 34 ” N, 89 ° 16 ’ 32 ” W, 205 m, 17 March 2003, D. Álvarez & C. Jiménez J. 4284 (MEXU); a 7.6 km al E del poblado “ Unión 20 de Junio ” (antes la Mancolona), 18 ° 44 ’ 55 ” N, 89 ° 13 ’ 48 ” W, 160 m, 18 August 2002, D. Álvarez, C. H. Ramos, E. Martínez S., F. Chiang & J. P. Abascal 1851 (MEXU); a 16 km al N de Xpujil, camino a Dzibalchén, 18 ° 39 ’ 18 ” N, 89 ° 24 ’ 29 ” W, 260 m, 12 October 1997, E. Martínez S., D. Álvarez, S. Ramírez, E. Lira & E. Madrid 28826 (MEXU); Zoh-Laguna, por la laguna del pueblo, 18 ° 35 ’ 39 ” N, 89 ° 24 ’ 48 ” W, 290 m, 5 September 1997, G. Bacab W. 61 (MEXU, TEX); a 65 km al N de Xpujil, camino a Dzibalchén, 19 ° 2 ’ 42 ” N, 89 ° 18 ’ 06 ” W, 140 m, 29 October 1997, E. Martínez S., D. Álvarez & S. Ramírez 29677 - A (MEXU); km 20 de la carretera Xpujil-Campeche, 18 ° 41 ’ 30 ” N, 89 ° 24 ’ 13 ” W, 270 m, 12 October 1997, E. M. Lira C., E. Martínez, D. Álvarez, S. Ramírez & E. Madrid 83 (MEXU); a 15 km al N de Xpujil, camino a Dzibalchén, 18 ° 39 ’ 42 ” N, 89 ° 24 ’ 27 ” W, 330 m, 11 August 1997, E. Martínez S., D. Álvarez & S. Ramírez 28366 (MEXU); Mun. [Calakmul], a 4 km al N de Zoh-Laguna, sobre el camino a Dzibalchén, 18 ° 40 ’ N, 89 ° 26 ’ W, 200 m, 3 September 1996, P. Álvaro M. 534 (MEXU); a 10 km al S de Xcan-ha, camino a Xpujil, 19 ° 1 ’ 28 ” N, 89 ° 17 ’ 38 ” W, 82 m, 25 June 1997, E. Martínez S. & D. Álvarez M. 27410 (MEXU); Mun. Calkiní, 11 km al W de Tankuché hacia Isla Arena, al sur de la carretera, 20 ° 31 ’ 50 ” N, 90 ° 20 ’ 45 ” W, 31 October 1993, F. Tun, J. C. Trejo & R. Durán 62 (CICY); Mun. Campeche, 3 km al E de Castamay carretera Castamay-Hopelchén, 19 ° 49 ’ 25 ” N, 90 ° 24 ’ 40 ” W, 25 February 1992, M. Méndez, R. Durán & G. Campos-Ríos 515 (CICY, MEXU); Mun. Carmen, en Finca Mamantel, sobre el río Las Cruces, en el sistema pluvio-lagunar del Río Palizada, approx. 18 ° 20 ’ 25 ” N, 91 ° 41 ’ 10 ” W, 25 November 1987, E. Cabrera & H. de Cabrera 14965 (MEXU); Vapor, approx. 18 ° 24 ’ 6 ” N, 91 ° 50 ’ 20 ” W, 25 - 28 July 1939, E. Matuda 3903 (F, GH, MEXU); Mun. Champotón, a 2 km al N de Seybaplaya. camino a Payacán Punta Morritos, 19 ° 39 ’ 4 ” N, 90 ° 42 ’ 20 ” W, 10 m, 3 May 1998, E. Martínez S. 30741 - A (MEXU); Mun. Hopelchén, a 4.61 km. al ENE de Chan-Chen, 19 ° 13 ’ 13 ” N, 89 ° 13 ’ 22 ” W, 112 m, 5 August 2004, D. Álvarez, A. Ramírez & E. Sosa 1032 bis (MEXU); a 3 km al S de Xcan-ha, camino a Xpujil, 19 ° 4 ’ 24 ” N, 89 ° 19 ’ 18 ” W, 80 m, 29 June 1997, E. Martínez S. & D. Álvarez M. 27457 (MEXU); 19 ° 4 ’ 23 ” N, 89 ° 19 ’ 18 ” W, 120 m, 17 November 1997, E. Martínez S., D. Álvarez & S. Ramírez 29795 (MEXU); 12 November 1997, E. Madrid N., D. Olguera, D. Álvarez, E. Martínez & E. Lira 362 (MEXU); a 5.3 km al NO de Chan-Chen, 19 ° 14 ’ 21 ” N, 89 ° 13 ’ 26 ” W, 106 m, 11 June 2004, D. Álvarez, A. Ramírez, C. H. Ramos, E. Martínez S. & F. Sosa M. 8855 (MEXU); Mun. Palizada, Santa Elena-Palizada, 18 ° 5 ’ 52 ” N, 92 ° 2 ’ 18 ” W, 6 m, 17 January 1982, C. Chan 1164 (CICY). Quintana Roo: Mun. [Bacalar], 4 km from Margarita Maza to Nuevo Progreso, approx. 19 ° 5 ’ 7 ” N, 88 ° 37 ’ 43 ” W, approx. 32 m, 3 July 2002, P. Acevedo & F. May Pat 12258 (CICY, MEXU, US); 3 – 4 km al oeste de Nuevo Progreso, unos 24 km al oeste de Graciano Sánchez (La Pantera), 19 ° 04 ’ 30 ” N, 88 ° 42 ’ 10 ” W, 2 July 1997, G. Carnevali, F. May & D. L. Benzing 4502 (CICY); Mun. Felipe Carrillo Puerto, a 38 km. al E de F. Carrillo Puerto, rumbo a Vigía Chico, approx. 19 ° 46 ’ 5 ” N, 87 ° 44 ’ 40 ” W, 15 October 1980, O. Téllez, M. García & E. Cabrera 3737 (MEXU); Sian Ka’an Biosphere Reserve, 30 km NE of Carrillo Puerto, 19 ° 50 ’ N, 87 ° 50 ’ W, 2 November 1984, D. A. Neill, T. L. Wendt, I. Olmsted, R. Durán G. & F. Chiang C. 5771 (MO); Mun. José María Morelos, a 4.15 km. al E del poblado Plan de la Noria, 19 ° 18 ’ 27 ” N, 88 ° 44 ’ 54 ” W, 96 m, 16 March 2004, D. Álvarez & A. Ramírez 8209 (MEXU); a 2.78 km. al N del poblado Zafarrancho, 19 ° 32 ’ 14 ” N, 88 ° 52 ’ 23 ” W, 88 m, 19 March 2004, D. Álvarez & A. Ramírez 8462 (MEXU); a 0.8 km. al O de San Isidro Poniente, 19 ° 21 ’ 36 ” N, 88 ° 57 ’ 28 ” W, 111 m, 18 June 2005, E. Martínez, A. Castañeda, A. Ramírez, C. H. Ramos & D. Álvarez 37879 (MEXU); Mun. Othón P. Blanco, a 15 km. al NO de Tomás Garrido, sobre el camino a Dos Aguadas, approx. 18 ° 6 ’ 22 ” N, 89 ° 5 ’ 26 ” W, 2 July 1984, E. Cabrera & H. de Cabrera 6591 (MEXU). Yucatán: Mun. Hunucmá, a 12 km. al NO de Hunucmá, sobre el camino a Sisal, approx. 21 ° 6 ’ N, 89 ° 68 ’ 10 ” W, 26 December 1985, E. Cabrera & H. de Cabrera 10411 (MEXU); Hunucmá, 5 km de la carretera que va de Hunucmá a Sisal, 21 ° 2 ’ 30 ” N, 89 ° 54 ’ 55 ” W, 4 October 1999, I. Ramírez, F. Chi & F. May 852 (CICY); Mun. Kinchil, 23 km al E de Celestún, 15 August 1985, E. Estrada 298 (CICY); Mun. Progreso, km. 33, Mérida road, approx. 21 ° 16 ’ 35 ” N, 89 ° 39 ’ 42 ” W, 23 July 1938, C. L. Lundell & A. A. Lundell 8065 (GH, MEXU, MICH, TEX). BELIZE. Orange Walk: Honey Camp, 18 ° 02 ’ N, 88 ° 26 ’ W, October 1929, C. L. Lundell 540 (F, GH, SMU). GUATEMALA. Petén: Puerto Chimino, Laguna Petexbatún, 20 km S of Sayaxché, 16 ° 25 ’ 53 ” N, 90 ° 11 ’ 28 ” W, October-December 1989, H. Zomer 114 (F); Tikal, Tikal National Park, 17 ° 13 ’ 30 ” N, 89 ° 36 ’ 47 ” W, 13 May 1959, C. L. Lundell 15990 (TEX).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E424265BAE9AA29DFABAF8C5.taxon	materials_examined	Type: — MEXICO. Veracruz: Hacienda de la Laguna, August 1829, C. J. W. Schiede 162 (Holotype, HAL- 98553, photo!; isotypes MO / BC: MO- 078171, photo!, MO / A: 2760903, photo!) Notes: — This is a species from tropical to premontane humid forests at elevations of 50 – 1000 (– 1900) m. It is widespread in Mexico, particularly on the Atlantic slope from Tamaulipas southward to the Guatemalan Petén. It is much more uncommon on the Pacific drainage, with records in coastal Oaxaca, Guerrero, and Michoacán. It is relatively common in the southern, more humid portions of the YPBP, particularly in the Guatemalan Petén and northern Belize. The species is distinctive in its anther appendages, which are distally bilobed (hence the name). They are white and also relatively large as compared with other local Gonolobus. The petals are elliptic, not obviously bent dextrogyrously, rounded to obtuse at apex and the corolla is shortly cup-like at the base (Figs. 1 C, 3 C). Specimens examined — MEXICO. Campeche: Mun. Calakmul, a 11 km al S de Ley de Fomento Agropecuario, camino a Dos Naciones, 17 ° 59 ’ 52 ” N, 89 ° 23 ’ 13 ” W, 300 m, 21 May 1997, E. Martínez S., D. Álvarez & P. Álvaro M. 27372 (MEXU); a 7.9 km al NO de El Civalito, 17 ° 56 ’ 32 ” N, 89 ° 14 ’ 22 ” W, 81 m, 18 May 2002, D. Álvarez & J. Calónico S. 1276 bis (MEXU); a 7.3 km al S del poblado Ley de Fomento Agropecuario, 17 ° 59 ’ 57 ” N, 89 ° 24 ’ 43 ” W, 247 m, 12 August 2003, D. Álvarez 6177 (MEXU); a 10 km al SE de Ley de Fomento Agropecuario, camino a Dos Naciones, 18 ° N, 89 ° 42 ’ 41 ” W, 205 m, 23 October 1997, E. Martínez S., D. Álvarez, S. Ramírez, E. Lira & E. Madrid 29136 (MEXU). Quintana Roo: Mun. Othón P. Blanco, Civalito, L. Ibarra-González s. n. (unvouchered). BELIZE. Orange Walk: 3.3 km S of Program for Belize Camp, 17 ° 45 ’ N, 89 ° 09 ’ W, 15 May 1991, R. Arvigo, P. Cocom, R. Cocom, N. Romero, G. Shropshire & J. Woodland 529 (MO); 0.5 m N of San Antonio village, 18 ° 08 ’ N, 88 ° 41 ’ W, 29 June 1974, P. W. Leino 306 (MO); Indian Church, 17 ° 46 ’ N, 88 ° 39 ’ W, 15 May 1977, T. Arnason & J. Lambert 17543 (MO). GUATEMALA. Petén: East of km 179, on Cadenas Road, 15 ° 54 ’ 14 ” N, 89 ° 13 ’ 49 ” W, 14 June 1970, E. Contreras 10065 (MEXU, MO); [Sitio arqueológico], en el camino que conduce al caserío La Llorona, 2.0 – 3.5 km [SO] de la aldea de Uaxactún, 17 ° 22 ’ 39 ” N, 89 ° 39 ’ 23 ” W, 30 May 1973, R. Tun Ortíz 2667 (F); Laguna Yaxja, collection from banks of Laguna Yaxja, 17 ° 03 ’ 49 ” N, 89 ° 23 ’ 30 ” W, 28 June 1970, W. E. Harmon & J. D. Dwyer 2743 (MO); Parque Nacional Tikal, alrededor del Grupo E, lado N, 17 ° 13 ’ 30 ” N, 89 ° 36 ’ 47 ” W, 28 May 1971, R. Tun Ortíz 1795 (F, MO, NY); Dos Lagunas, El Cedro, km 8, 17 ° 42 ’ 16 ” N, 89 ° 24 ’ 25 ” W, 21 April 1969, E. Contreras 8367 (DS, MO, NY); Dos Lagunas, Ixcanrio, bordering Ixcanrio River, 17 ° 44 ’ 56 ” N, 89 ° 18 ’ 12 ” W, 24 May 1969, E. Contreras 8636 (DS, F, MO); Tikal, Tikal National Park, bordering airfield, 17 ° 13 ’ 30 ” N, 89 ° 36 ’ 47 ” W, 5 June 1959, C. L. Lundell 16052 (F, MO, TEX); Cerro Cauhui [Cahui], 16 ° 59 ’ 46 ” N, 89 ° 42 ’ 59 ” W, 20 May 1986, R. L. Walker 1429 (MO); La Libertad and vicinity, 16 ° 47 ’ 17 ” N, 90 ° 06 ’ 53 ” W, 18 June 1934, M. Aguilar H. 307 (MO, WIS).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E424265AAE9AA77FFC15FBF7.taxon	materials_examined	Type: — GUATEMALA, H. Bartlett 12300 (Holotype, MO / BC: MO- 078253 / A: 1041429, photo! (Fig. 2 D); isotypes, MICH- 1111617, photo!, MO- 1041473 (Fig. 2 C), photo!, US- 00111087, photo!).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E424265AAE9AA77FFC15FBF7.taxon	discussion	Notes: — A distinctive species whose generic position has been long disputed. The glabrous, lanceolate foliar blades, at least three times longer than wide are unusual in Gonolobus and unique in the YPBP among members of the genus. The foliar blades are only shallowly cordate at the base; all other Gonolobus in the area have predominantly ovate, ovateelliptic, or ovate-oblong foliar blades that are sharply cordate at base and only about 2 – 2.5 times longer than wide. The flowers of this species are relatively small with white corolla lobes 7 – 8 × 3.5 – 4 mm. This species is closely related to the extralimital G. hammelii W. D. Stevens (2005 b: 235) (from Costa Rica), G. hadrostemma Stevens (2005 b: 233 - 235) (Nicaragua and Costa Rica), Matelea manarae Morillo (in Steyermark 1978: 48 - 49) (from coastal Venezuela) and a few others. All feature similar foliage and are atypical in Gonolobus in having a massive corona adnate to the faucal annulus. Furthermore, the anthers lack the free appendages that characterize the genus (Stevens 2005 b). These species have been transferred to Atrostemma Morillo (2015 b: 198), a taxonomic decision that may have some merit.	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E424265AAE9AA77FFC15FBF7.taxon	description	Gonolobus glaberrimus is known from two collections, both from the Guatemalan Petén, where it grows in tropical rain forest at elevations of 175 – 190 m. It is probably a rare, inconspicuous species and probably difficult to spot even in flower or fruits. There is a collection at MO (I Inbio 159, photo!) from Estación Biológica Maritza, Guanacaste, Costa Rica identified as this species by a specialist (J. F. Morales). However, the specimen is poor, the leaves are all folded-up and the shape looks somewhat different. Also, it does not have mature flowers (“ immature fruits ”), which are necessary for positive identification. Furthermore, it is isolated from the other three localities by more than 850 km. Because of all these arguments, we have decided to consider G. glaberrimus as endemic to the southern portion of the YPBP until more conclusive evidence proves otherwise (Figs. 1 C, 2 C-D). IUCN Conservation assessment. — EN. Gonolobus glaberrimus is known from only two localities and three collections. Thus, AOE cannot be estimated at this time and the AOO is of 8 km 2. The two localities are 18 – 19 km apart. It is likely that the species is restricted to the area of the Guatemalan Petén and that when further localities are recorded, we will be able to reassess its conservation status probably as EN (Endangered). Although the species is rare, its known populations are located the Tikal National Park, which affords them some degree of protection for the foreseeable future.	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E424265AAE9AA77FFC15FBF7.taxon	materials_examined	Specimens examined: — GUATEMALA. Petén: Tikal National Park, on [along] Remate Road, 17 ° 13 ’ 30 ” N, 89 ° 36 ’ 47 ” W, 190 m, 15 January 1962, C. L. Lundell 17103 (LL, MO).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E4252644AE9AA420FAB4FB07.taxon	materials_examined	Type: — GUATEMALA. Dept. Alta Verapaz, Cubilquitz, 350 m, October 1901, H. von Türckheim 8243 (Holotype, US- 01338610, photo!).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E4252644AE9AA420FAB4FB07.taxon	description	Specimens examined: — GUATEMALA. Petén: Dolores, between km 73 / 72 of Santo Toribio road, 16 ° 31 ’ 45 ” N, 89 ° 27 ’ 15 ” W, 21 July 1961, E. Contreras 2637 (CAS, MEXU, MO, TEX); Dolores, bordering Río Ixcol, 1 km East, 16 ° 30 ’ 45 ” N, 89 ° 23 ’ 54 ” W, 3 June 1961, E. Contreras 2415 (TEX); La Cumbre, km 138 / 137 of Cadenas Road, 16 ° 04 ’ 52 ” N, 89 ° 21 ’ 03 ” W, 270 m, 26 September 1966, E. Contreras 6246 (F, LL, MEXU, MO); La Cumbre, bordering Cadenas Road, km 143, 16 ° 04 ’ 52 ” N, 89 ° 21 ’ 03 ” W, 270 m, 1 September 1969, E. Contreras 9036 (CAS, DUKE, MO, TEX); San Luis, 16 ° 11 ’ 59 ” N, 89 ° 26 ’ 31 ” W, 12 July 1959, C. L. Lundell 16385 (CAS, F, MO, TEX); Tikal, Tikal National Park, 17 ° 13 ’ 30 ” N, 89 ° 36 ’ 47 ” W, 4 July 1959, C. L. Lundell 16172 (CAS, DUKE, F, MEXU, MO, TEX); 24 September 1959, E. Contreras 168 (CAS, F, MO, TEX); Tikal, Parque Nacional, frente Templo No. 4, 17 ° 13 ’ 30 ” N, 89 ° 36 ’ 47 ” W, 8 November 1969, R. Tun Ortíz 428 (DS, F, MO).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E4252644AE9AA420FAB4FB07.taxon	materials_examined	Type: — BELIZE. Tower Hill, 1928, J. S. Karling 27 (Holotype, F- 0044022 F, photo!; isotype US- 00112339, photo!). Notes: — Gonolobus stenanthus is one of the endemic species of the YPBP. It is readily diagnosed by its relatively large, conspicuously reflexed calyx lobes (11 – 14 × 3.8 – 5.5 mm), which are easily visible both in live and in herbarium material. Furthermore, the corolla lobes are triangular-lanceolate, acute, and the right margin is bright white. The corona is bright yellow, pubescent. This species is relatively widespread within the YPBP, particularly in the eastern and southern portions, covered by seasonally dry forests with precipitations in the range of 1000 – 1500 mm. Recent treatments of the Gonolobus of the YPBP (Stevens 2010; Carnevali et al. 2010) have treated G. yucatanensis as a synonym of G. stenanthus. Both entities are vegetatively indistinguishable and dry flowers look extremely alike. However, G. stenanthus comes in two color morphs. In the type collection (J. S. Karling 27, F, photograph!, type of the basionym, Vincetoxicum stenanthum Standley (1929: 255), the flowers have dried of a dull pale green, a pattern associated with the typical green corollas of the species in populations coming from northern Belize, the Guatemalan Petén, and southern Quintana Roo and Campeche. Thus, plants matching this type have bright green or yellow-green petals; the stylar head of the gynostegium as well as the anther appendages are yellow (Fig. 1 D, 3 E-F). However, populations of G. stenanthus on the northern, drier edge of its distribution in eastern Yucatán and northern Quintana Roo States, typically feature extremely dark chestnut to reddish brown, almost black corollas (Fig. 1 D, 3 G-I). The type of Trichostelma yucatanensis (Steere 2641, MO) is very poorly preserved, but the original diagnosis clearly states that the flowers have an “ … atrocarneae … ” corolla, which indicates that the name can be applied to the dark-colored populations on the northern edge of the distribution of G. stenanthus. Furthermore, while the corona is also bright yellow (as in typical plants), the stylar head of the gynostegium and the anther appendages are dark reddish maroon, creating a sharp color contrast. Photographs of both color morphs of the species are strikingly distinct, suggesting they may be reproductively isolated and could constitute different species. Because the dark colored populations are geographically restricted but contiguous to the typical, more common and more southernly distributed green-flowered populations, and both sets of populations are morphologically distinctive in flower color and ecologically different, we propose to treat Gonolobus yucatanensis as a subspecies of G. stenanthus. This decision requires the following nomenclatural change:	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
03DEFD71E4252644AE9AA420FAB4FB07.taxon	materials_examined	Type: — Mexico: Quintana Roo: in low forest, San Miguel, Cozumel Island, 6 - 8 Aug 1932, W. C. Steere 2641 (Holotype, MO / BC: MO- 078214 / A: 1064813, photo!; isotypes MICH- 1000055 A, photo!, MICH- 1000055 B, photo!). IUCN Conservation assessment: Here we will assess the species a as a whole and the subspecies individually. Gonolobus stenanthus — NT. The species meets criterion B 1 a, b (i, ii, iii, iv) for a Least Concern species (LC) and B 2 a, b (i, ii, iii, iv) for Endangered species (EN). It is known to us from 27 localities in the three Mexican states of the YPBP, as well as from northern Belize (Orange Walk). Its extent of occurrence is of 77,475.415 km 2 (LC) and its AOO = 96.000 km 2 (EN). Furthermore, the species does not have two of the three additional conditions to meet the requirements for neither the category of an Endangered (EN) nor a Vulnerable (V) species. For this reason, as well as the occurrence of the subspecies in two naturally protected areas (Calakmul Biosphere Reserve, and Sian Ka’an Biosphere Reserve), we propose the species to be treated as Near Threatened (NT). Gonolobus stenanthus subsp. stenanthus — NT. Occupying most of the range of the species, this subspecies is the most common and widespread with 20 collection localities, with an EOO = 59,039.2 km 2 (LC) and an AOO = 72.0 km 2 (EN). All the statements for the whole species apply here. Gonolobus stenanthus subsp. yucatanensis — EN. This subspecies is currently known from seven localities and has an EOO of 3,565.9 km 2 (EN) and an AOO of 28.0 km 2 (EN). Most of the localities for this species are in areas where anthropic disturbances are strong and are likely to become subject to increased pressure. Several of the known localities are in the vicinities of large urban centers (Valladolid in Yucatán, Tulum in Quintana Roo) and will be most likely soon affected. However, the species has been collected near at least three protected archaeological zones (Chichén Itza, Coba, and Tulum) where at least some degree of protection for the foreseeable future is guaranteed. Specimens examined: — Gonolobus stenanthus subsp. stenanthus. MEXICO. Campeche: Mun. Calakmul, Zoh-Laguna, 18 ° 35 ’ 39 ” N, 89 ° 24 ’ 48 ” W, 290 m, 19 May 1997, P. Álvaro M. & D. Álvarez 730 (MEXU); a 2 km al W de Calakmul, camino a La Laguna, 18 ° 7 ’ 28 ” N, 89 ° 48 ’ 56 ” W, 184 m, 12 July 1997, E. Martínez S., D. Álvarez & S. Ramírez 27689 (MEXU); Ejido Nuevo Becal, parcela 6, 18 ° 40 ’ 54 ” N, 89 ° 23 ’ 47 ” W, 16 August 2006, M. A. Islas Luna 1950 (CICY, CIQR); Cerro Civalito, km 4.5 carretera Civalito-Dos Lagunas, 17 ° 52 ’ 43.5 ” N, 89 ° 20 ’ 29.1 ” W, 200 m, 8 July 2009, L. Ibarra & A. Torres C. 603 (CICY); 22 July 2009, L. Ibarra & A. Torres C. 609 (CICY); Mun. [Calakmul], 6 km al O de la desviación a Calakmul, aprox. km 105 de la carr. Escárcega-Chetumal, approx. 18 ° 32 ’ 35 ” N, 89 ° 57 ’ 24 ” W, approx. 159 m, 30 July 1987, E. Cabrera & H. de Cabrera 14176 (MEXU); 12 km al S de Conhuas, sobre el camino al centro Ceremonial de Calakmul, entrando por el km 98 de la carretera Escárcega-Chetumal, 18 ° 28 ’ 2 ” N, 89 ° 53 ’ 30 ” W, 27 July 1986, E. Cabrera C. & H. de Cabrera 11845 (MEXU); Mun. [Carmen], Monterrey, approx. 18 ° 23 ’ 60 ” N, 91 ° 7 ’ W, 23 January 1932, C. L. Lundell 1237 (DS, F, MO, NY, WIS); Mun. Hopelchén, a 2.44 km al NO de Pachuitz, 19 ° 9 ’ 53 ” N, 89 ° 15 ’ 24 ” W, 143 m, 29 May 2004, D. Álvarez 8823 (MEXU); a 2.3 km al S de Chan-Chen, camino a Pachuitz, 19 ° 11 ’ 15 ” N, 89 ° 15 ’ 42 ” W, 136 m, 16 June 2004, D. Álvarez, A. Ramírez, C. H. Ramos, E. Martínez S. & F. Sosa M. 9230 (MEXU); a 3.2 km al SE de Chan-Chen, 19 ° 11 ’ 18 ” N, 89 ° 14 ’ 26 ” W, 113 m, 13 June 2004, D. Álvarez, A. Ramírez, C. H. Ramos, E. Martínez S. & F. Sosa M. 9032 (MEXU). Quintana Roo: Mun. Benito Juárez, a 1 km al Este de la Cd. Cancún, approx. 21 ° 19 ’ 50 ” N, 86 ° 48 ’ 30 ” W, 12 September 1982, E. Cabrera & H. de Cabrera 3482 (MEXU); Mun. F. Carrillo Puerto, a 44 km al Norte de F. Carrillo Puerto, approx. 19 ° 55 ’ 30 ” N, 88 ° 12 ’ 34 ” W, 9 September 1980, O. Téllez, E. Cabrera & L. Rico 3509 (MEXU); 10 km al NE de F. Carrillo Puerto sobre el camino a Vigía Chico, approx. 19 ° 37 ’ 15 ” N, 87 ° 57 ’ 30 ” W, 6 July 1989, E. Cabrera 16475 (MEXU); Mun. [Tulum], Cobá, zona arqueológica, sacbé # 1 y # 3, 20 ° 30 ’ 40 ” N, 87 ° 43 ’ 10 ” W, A. Barrera 484 (CICY); Cobá, zona arqueológica, grupo Cobá, 20 ° 29 ’ 15 ” N, 87 ° 44 ’ W, 15 May 1981, E. Ucán & J. S. Flores 1120 (CICY); 22 March 1994, R. R. Sears 75 (CICY). Yucatán: Mun. Tekax, a 18.9 km al ESE de Nohanal, 19 ° 43 ’ 45 ” N, 89 ° 9 ’ 58 ” W, 90 m, 17 June 2004, D. Álvarez, A. Ramírez, C. H. Ramos, E. Martínez S. & F. Sosa M. 9293 (MEXU). BELIZE. Orange Walk: Vicinity of Tower Hill, 18 ° 01 ’ N, 88 ° 31 ’ W, 1928, J. S. Karling 27 (F, MO); Honey Camp, 18 ° 02 ’ N, 88 ° 26 ’ W, October 1929, C. L. Lundell 536 (DS, F). Gonolobus stenanthus subsp. yucatanensis. MEXICO. Quintana Roo: Mun. Cozumel, San Miguel in forest of Cozumel Island, 20 ° 29 ’ 18 ” N, 86 ° 55 ’ 56 ” W, 6 – 8 August 1932, W. C. Steere 2641 (MICH, MO); Mun. [Tulum], Ruinas de Cobá, approx. 20 ° 29 ’ 30 ” N, 87 ° 43 ’ 55 ” W, 28 June 1986, J. Palma G. s. n. (CIQR, MEXU); 20 ° 31 ’ N, 87 ° 39 ’ W, June-July 1938, C. L. Lundell & A. A. Lundell 7700 (A, F, GH, MICH, NY, SMU, TEX); 20 ° 28 ’ 48 ” N, 87 ° 43 ’ 48 ” W, June-July 1938, C. L. Lundell & A. A. Lundell 7765 (MICH, TEX); C. L. Lundell & A. A. Lundell 7801 (MICH); along road from Tulúm to Cobá, approx. 20 ° 17 ’ 20 ” N, 87 ° 30 ’ 15 ” W, 26 June 2002, P. Acevedo & F. May Pat 12190 (CICY, NY, US). Yucatán: Mun. Tinúm, Chichén Itza, near Pisté, approx. 20 ° 40 ’ 15 ” N, 88 ° 34 ’ 20 ” W, June-July 1938, C. L. Lundell & A. A. Lundell 7577 (GH, MEXU, MICH); Mun. Valladolid, La Isla, un centro de descanso y gasolinera, km 143 autopista Mérida-Cancún, 20 ° 44 ’ 39.62 ” N, 88 ° 13 ’ 52.96 ” W, 27 – 30 m, 9 August 2018, G. Carnevali, R. Duno & J. Márquez 8377 (CICY, CHIP, CIQR, F, FCME, G, GH, MEXU, MO, SEL, UADY, UCAM, UJAT, XAL).	en	Carnevali, Germán, Romero-González, Gustavo A., Tapia-Muñoz, José Luis, Ramírez-Morillo, Ivón M., Ramírez-Díaz, Claudia J., Cetzal-Ix, William, Stefano, Rodrigo Duno De, Romero-Soler, Katya J. (2022): Twice lost, twice found: A new species of Gonolobus (Apocynaceae: Asclepiadoideae) with a reappraisal of the genus in the Yucatan Peninsula Biotic Province. Phytotaxa 530 (2): 141-162, DOI: 10.11646/phytotaxa.530.2.2
