A new endemic species and species richness distribution of the genus Pinguicula (Lentibulariaceae) in the Trans-Mexican Volcanic Belt, Mexico

Abstract

Background:
The genus Pinguicula harbors 110 species, of which 53 are distributed in Mexico. The formation of the Mexican mountains has favored the Pinguicula diversification. Pinguicula specimens collected in the State of México, along the Trans-Mexican Volcanic Belt (TMVB) do not correspond with any known species.

Questions:
Do the collected specimens belong to a new species? What is its conservation status? How many Pinguicula species are there along the TMVB and how do they differentiate? How is the Pinguicula species richness distributed?

Studied species:
Pinguicula.

Study site and dates:
TMVB, 2005-2023.

Methods:
Based on herbarium specimens and recently collected material, a morphological analysis and description were made. Conservation status was assessed following IUCN Red List Categories and Criteria. Herbarium specimens and digital records of Pinguicula from the TMVB were examined to generate a list and key. We analyzed the richness distribution of Pinguicula by states, vegetation types, elevation ranges, and grid cells.

Results:
Pinguicula tlahuica is proposed as a new species. It is distinguished by the linear-spatulate summer leaves. The new species falls into the Endangered (EN) category. Along the TMVB, 16 species of Pinguicula are distributed. The State of México, Hidalgo and Michoacán, and the pine-oak forest were the richest. Pinguicula appeared between 759-3,427 m asl. The grid cell analyses revealed different areas with high richness.

Conclusions:
Along the TMVB, the Pinguicula species richness centered on the Eastern and Western sectors. Pinguicula crassifolia, P. michoacana, P. tlahuica, and P. zamudioana are endemic to the TMVB.

Full text

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López-Pérez et al. / Botanical Sciences
A new endemic species And species richness distribution of the genus pinguiculA
(lentibulAriAceAe) in the trAns-mexicAn VolcAnic belt, mexico
Jorge dAVid lópez-pérez1, sergio zAmudio2, guAdAlupe munguíA-lino3,4,* & AArón rodríguez4,5
1Doctorado en Ciencias en Biosistemática, Ecología y Manejo de Recursos Naturales y Agrícolas (BEMARENA), Centro
Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, Mexico.
2Independent Researcher, Pátzcuaro, Michoacán, Mexico.
3Cátedras Conahcyt-Universidad de Guadalajara, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de
Guadalajara, Zapopan, Jalisco, Mexico.
4Laboratorio Nacional de Identificación y Caracterización Vegetal (LaniVeg), Consejo Nacional de Humanidades, Ciencias y
Tecnologías (Conahcyt), Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan,
Jalisco, Mexico.
5Herbario Luz María Villareal de Puga del Instituto de Botánica (IBUG), Departamento de Botánica y Zoología, Centro
Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, Mexico.
*Author for correspondence: gmlinno@gmail.com
Botanical Sciences
DOI: 10.17129/botsci.3485
Received: February 8, 2024, Accepted: April 17, 2024
On line rst: June 27, 2024
Taxonomy and Floristics / Taxonomía y Florística
This is an open access article distributed under the terms of the Creative Commons Attribution License CCBY-NC (4.0) international.
https://creativecommons.org/licenses/by-nc/4.0/
Abstract
Background: The genus Pinguicula harbors 110 species, of which 53 are distributed in Mexico. The formation of the Mexican mountains has
favored the Pinguicula diversication. Pinguicula specimens collected in the State of México, along the Trans-Mexican Volcanic Belt (TMVB)
do not correspond with any known species.
Questions: Do the collected specimens belong to a new species? What is its conservation status? How many Pinguicula species are there along
the TMVB and how do they differentiate? How is the Pinguicula species richness distributed?
Studied species: Pinguicula.
Study site and dates: TMVB, 2005-2023.
Methods: Based on herbarium specimens and recently collected material, a morphological analysis and description were made. Conservation status
was assessed following IUCN Red List Categories and Criteria. Herbarium specimens and digital records of Pinguicula from the TMVB were
examined to generate a list and key. We analyzed the richness distribution of Pinguicula by states, vegetation types, elevation ranges, and grid cells.
Results: Pinguicula tlahuica is proposed as a new species. It is distinguished by the linear-spatulate summer leaves. The new species falls into
the Endangered (EN) category. Along the TMVB, 16 species of Pinguicula are distributed. The State of México, Hidalgo and Michoacán, and the
pine-oak forest were the richest. Pinguicula appeared between 759-3,427 m asl. The grid cell analyses revealed different areas with high richness.
Conclusions: Along the TMVB, the Pinguicula species richness centered on the Eastern and Western sectors. Pinguicula crassifolia, P. michoa-
cana, P. tlahuica, and P. zamudioana are endemic to the TMVB.
Keywords: butterworts, carnivorous plants, diversication, Mexican Transition Zone, Pinguicula section Orcheosanthus.
Resumen
Antecedentes: Pinguicula agrupa 110 especies, 53 crecen en México. La formación de las montañas mexicanas ha favorecido su diversicación.
Ejemplares provenientes del Estado de México, en la Faja Volcánica Trans-Mexicana (FVTM) no corresponden con alguna especie conocida.
Preguntas: ¿Los ejemplares recolectados representan una especie nueva? ¿Cuál es su estado de conservación? ¿Cuántas especies de Pinguicula
crecen en la FVTM y cómo se diferencian? ¿Cómo se distribuye la riqueza de especies en la FVTM?
Especies estudiadas: Pinguicula.
Lugar y fechas del estudio: FVTM, 2005-2023.
Métodos: Con base en especímenes de herbario y muestras recolectadas recientemente se realizaron un análisis morfológico y una descripción.
El estado de conservación se evaluó siguiendo las Categorías y Criterios de la Lista Roja de la UICN. Ejemplares de herbario y registros digi-
tales de Pinguicula en la FVTM fueron examinados para generar una lista de especies y una clave. La riqueza fue analizada por estados, tipos
de vegetación, rangos de elevación y celdas.
Resultados: Pinguicula tlahuica es propuesta como especie nueva, distinguible por las hojas de verano linear-espatuladas. Es considera dentro
de la categoría En Peligro (EN). En la FVTM crecen 16 especies de Pinguicula. El Estado de México, Hidalgo y Michoacán, y el bosque de
pino-encino son los más ricos. Pinguicula crece entre 759-3,427 m snm. Los análisis de celdas recuperaron distintas áreas con riqueza alta.
Conclusiones: En la FVTM, la riqueza de especies de Pinguicula está en los sectores Oriental y Occidental. Pinguicula crassifolia, P. michoa-
cana, P. tlahuica y P. zamudioana son endémicas de la FVTM.
Palabras clave: diversicación, Pinguicula sección Orcheosanthus, pinguiculas, plantas carnívoras, Zona de Transición Mexicana.
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Lentibulariaceae is a family of carnivorous plants that includes the genera Genlisea A.St.-Hil. with 30 spe-
cies, Pinguicula L. with 110 species, and Utricularia L. with 271 species. Pinguicula is distinguished by
the presence of true roots, leaves grouped in a basal rosette, and bractless peduncles with a terminal ow-
er (Casper 1966). Based on morphological characters, Casper (1966) divided Pinguicula into P. subg.
Isoloba Barnhart, P. subg. Pinguicula L., and P. subg. Temnoceras Barnhart. Pinguicula subg. Isoloba includes spe-
cies with actinomorphic corollas, subequal lobes, white to white-purplish corolla, and trichomes arranged in three
rows inside the corolla tube. In contrast, P. subg. Pinguicula harbors species with bilabiate, blue or violet corollas,
and with the tube trichomes dispersed. Finally, P. subg. Temnoceras includes species with whitish bilabiate corol-
las, crenate or cleft apex lobes, the lobes of the upper lip shorter than the lower, and the tube trichomes arranged in
three rows.
Pinguicula grows in Eurasia, the Americas, and the Caribbean islands (Shimai et al. 2021). All three subgenera are
represented in Mexico, where 53 species have been recorded, 45 of which are endemics (López-Pérez et al. 2024).
In addition, in Mexico, the species of Pinguicula grows almost exclusively in the mountain chains. Due to the large
number of species and high endemism, Mexico represents a center of diversity for the group.
The Trans-Mexican Volcanic Belt morphotectonic province (TMVB) crosses central Mexico from east to west
between the 18° 30’ N and 21° 30’ N parallels. It includes, at least partially, the states of Colima, Guanajuato,
Hidalgo, Jalisco, Mexico, Mexico City, Michoacán, Morelos, Nayarit, Puebla, Querétaro, Tlaxcala, and Veracruz
(Ferrusquía-Villafranca 2007). The TMVB includes mountain ranges, volcanic structures, and intermountain pla-
teaus at different elevations ranging from Cerro San Juan in Nayarit to the Sierra de Chiconquiaco in Veracruz
(Gámez et al. 2012). The province is divided into the Eastern, Central and Western sectors (Ferrusquía-Villafranca
et al. 2007, Ferrari et al. 2012) and merges three major mountain ranges. The Eastern sector meets the Sierra
Madre Oriental and the Sierra Madre del Sur. Whereas the Western sector connects with the Sierra Madre Occi-
dental and the Sierra Madre del Sur. Whereby, the TMVB represents the nucleus of the Mexican Transition Zone
(MTZ; Halffter & Morrone 2017).
Ferrari et al. (2012) described the TMVB formation in four episodes. The rst episode showed a volcanic arc
during the Early and Mid Miocene (~20-10 Ma), followed by a pulse of mac volcanism during the Late Mio-
cene (~11-7 Ma). Then, between the Late Miocene and Early Pliocene (7.5-3 Ma), a silicic and bimodal episode
was recorded. Lastly, an arc from the Late Pliocene to the Holocene (2.5 Ma-present) is observed (Gómez-Tuena
et al. 2005, Ferrari et al. 2012). The TMVB displays the most recent orogenic processes with volcanism still
active (Gámez et al. 2012) and its uplift has favored the biogeographic transition, speciation, and persistence
of several taxa, such as the tribe Tigridieae B. M. Kittel (Munguía-Lino et al. 2015), Solanum L. sect. Petota
Dumort (Murillo-Pérez et al. 2022), the genera Cosmos Cav. and Lycianthes (Dunal) Hassl. (Vargas-Amado
et al. 2013, Anguiano-Constante et al. 2018), and populations of Nolina parviora Hemsl. (Ruiz-Sanchez &
Specht 2013).
During a systematic study of Pinguicula in Mexico, we collected material in the Eastern sector of the TMVB,
which did not correspond with any previously known species. Here, we propose it as a new and endemic species. In
addition, we analyzed the species richness distribution of Pinguicula along this province. The extreme sectors of the
TMVB are the conuence of the three major mountain ranges. We expect that the species richness will be unevenly
distributed.
Materials and methods
Taxonomic treatment. We examined the specimens of Pinguicula from the IBUG, IEB, and MEXU herbaria (her-
barium acronyms per Thiers 2023). For the new species, the morphological description was accomplished based on
fresh material and herbarium specimens. The terminology followed Casper (1966), Moreno (1984), and Zamudio
(2001). We used the infrageneric classication proposed by Casper (1966). The color of the structures was designated
in accordance with the RHS Colour Chart (Royal Horticultural Society 2015).
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Conservation status. The conservation status of the new species was evaluated based on the IUCN Red List Catego-
ries and Criteria (IUCN 2022). The Area of Occupancy (AOO) was estimated with GeoCAT (Bachman et al. 2011).
Study area, database and species richness of Pinguicula. The TMVB is made up of volcanic successions, continen-
tal sedimentary deposits, and volcanic-sedimentary deposits situated in the intermountain depressions, whereby the
study area was delimited under the morphotectonic province criterion of Ferrusquía-Villafranca (2007). A morpho-
tectonic province has physiographic and geologic-tectonic features unique enough to distinguish it from such other
neighboring provinces (Ferrusquía-Villafranca 1993). The records from CHAP, CHAPA, ENCB, FCME, HUAP,
IBUG, IEB, INEGI, INIF, MEXU, QMEX, SLPM, and XAL herbaria (Thiers 2023), the digital herbaria CAS, K,
MO, and US (Thiers 2023), as well as the information available in the Global Biodiversity Information Facility
(GBIF 2023), the Southwest Environmental Information Network (Gilbert et al. 2019), and the Sistema Nacional de
Información sobre Biodiversidad de México (CONABIO 2020) were compiled and curated into a database. To assure
the taxonomic identity of the digital records, only specimens with images were examined. Specimens without geo-
graphical data were georeferenced using Google Earth Pro v. 9.191.0.0 (Google 2023), the Mapa Digital de México
v. 6.1 (INEGI 2023a) and following the recommendations of Garcia-Milagros & Funk (2010). The specimens with
ambiguous information were excluded. The species distribution maps were elaborated using the presence records of
Pinguicula along the TMVB.
Species richness distribution of Pinguicula along the TMVB. The species richness distribution was quantied by 1)
states, 2) vegetation types, 3) elevation ranges, and 4) grid cells. The shapes of states (INEGI 2018) and vegetation
types (Rzedowski 1978) were clipped with the TMVB polygon of Ferrusquía-Villafranca (2007). The distribution
richness analyses by states and vegetation types were carried out through a direct count of species documented in
each polygon. Species richness by elevation ranges was quantied based on 500 m intervals. The Continuo de Eleva-
ciones Mexicano 3.0 (INEGI 2023b) with a resolution of 15 m was used to assign the elevation value to each record.
The grid cell richness analyses were performed using a cell size of 0.21 × 0.21° based on Suárez-Mota & Villaseñor
(2011) method and 0.24 × 0.24° according to Oyala (2020) criterion.
Results
Pinguicula tlahuica López-Pérez & Zamudio, sp. nov. (Figures 1 and 2, Table 1).
Type. Mexico, Estado de México, municipio Ocuilan de Arteaga, parque Tlatucapa, Peña Redonda, 18° 57’ 56.6” N, 99°
24’ 58.5” W, 2,189 m snm, 12 April 2023, J. López-Pérez & G. Munguía-Lino 641 (Holotype: IBUG; Isotype: MEXU).
Diagnosis. Pinguicula tlahuica is morphologically similar to P. moranensis Kunth in the form and size of the ow-
ers, but it is distinguished from it by: the oblong to oblong-spathulate winter leaves; linear-spatulate summer leaves,
7.0-14.5 × 0.5-1.7 cm; blooming with winter rosette.
Description. Perennial herbs. Leaves dimorphic, arranged into basal rosettes; winter rosette compact, subhypogeous,
1.2-1.9 cm in diameter, leaves 55-70, succulent, petiole 0.5-2.5 mm long, oblong, spathulate to oblong-spathulate,
2.5-8.0 × 1.0-3.0 mm, acute to obtuse, pubescent; summer rosette lax, leaves 4-8, sessile, ascending, linear-spatulate,
7.0-14.5 × 0.5-1.7 cm, acute to obtuse, margin revolute, pubescent on the upper surface with sessile and stipitate
glandular trichomes. Peduncles 1-6 per plant, 4.0-12.0 cm long, pilosulose with stipitate glandular trichomes. Flow-
ers 3.0-5.0 cm long, including the spur; calyx bilabiate, outer surface pilosulose with stalked glandular trichomes;
upper lip trilobate, triangular lobes, 2.0 × 1.0 mm; lower lip bilobate, lobes triangular to lanceolate, 2.0 × 0.5 mm;
corolla bilabiate, blue-violet (violet-blue group 95A), with a white macula at the base of lower lip that extends to
the throat; upper lip bilobate, lobes oblong to obovate, 8.0-12.0 × 3.5-7.0 mm, truncate to obtuse; lower lip trilobate,
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Figure 1. Pinguicula tlahuica. A) Summer rosette. B) Flowering winter rosette. C) Summer leaves. D) Winter leaves. E) Stipitate glands on the leaf. F)
Flower frontal view. G) Flower lateral view. H) Fruit. Illustrated by Fatima Bracamontes based on type material (J. López-Pérez & G. Munguía-Lino 641).
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Figure 2. Pinguicula tlahuica. A) Habitat. B) Flower frontal view. C-D) Winter rosette with owers. E) Sterile winter rosette. F) Summer rosette. G)
Transition among winter and summer leaves. A-G by Jorge López-Pérez.
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lobes oblong to obovate, truncate to obtuse, lateral lobes 7.0-8.0 × 3.0-6.0 mm, the medium larger than the lateral
ones, 8.0-10.0 × 4.0-6.5 mm; corolla tube infundibuliform, 2.5-4.0 × 2.0-2.5 mm, pilosulose with stalked glandular
trichomes; spur cylindrical-subulate, 2.0-3.0 cm long, brown to green-greyish (brown group N200A, greyed-green
group 197B); ovary subglobose, 1.5 mm in diameter, glandular pilosulose; stigma bilobate, blue-violet (violet-blue
group 95A). Capsule globose, 4-5 mm in diameter. Seeds not seen.
Distribution and ecology. Pinguicula tlahuica is endemic to the TMVB. It grows in the municipalities of Ocuilan de
Arteaga, State of México, and Cuernavaca, Morelos (Figure 3). The area is part of a mega-stratovolcanoes alignment in
the Eastern sector of the TMVB (Ferrusquía-Villafranca 2007). Pinguicula tlahuica inhabits in ravines, on northeastern
facing igneous rock walls, within the oak forest at elevations of 1,860-2,190 m asl (Figure 2A). The plants grow in compact
groups, associated with mosses, and in sympatry with Bomarea edulis (Tussac) Herb., Calochortus pringlei B.L.Rob.,
Dahlia merckii Lehm., Svenkoeltzia congestiora (L.O.Williams) Burns-Bal, Hechtia sp., Nolina sp., and Pitcairnia sp.
Character P. gypsicola P. moranensis P. tlahuica
Winter rosette
Life form Subhypogeous Epigeous, hypogeous, and
subhypogeous
Subhypogeous
Rosette diameter (cm) 1.5-2 1-3 1.2-1.9
Leaf number 41-42 30-80 55-70
Leaf size (cm) 0.5-1.5 × 0.1-0.2 1-3 × 0.2-0.6 0.25-0.8 × 0.1-0.3
Leaf shape Spatulate to
elliptic-lanceolate
Lanceolate to oblong-lanceolate Spatulate to
oblong-spatulate
Summer rosette
Leaf orientation Ascendent Adpressed Ascendent
Leaf number 6-17 4-12 4-8
Leaf size (cm) 2.2-11 × 0.3-0.6 3.5-9.5 × 2.5-7.5 7-14.5 × 0.5-1.7
Leaf shape Linear lanceolate, cili-
ate at the base
Elliptic, obovate to suborbicular,
not ciliate
Linear-spatulate,
not ciliate
Flower length (cm) 3-4 2.5-6 3-5
Corolla upper lobes size (mm) 7-10 × 2-5 7-18 × 4-11 8-12 × 3.5-7
Corolla lower lobes size (mm) 6-11 × 3-7 6.5-11.5 × 4.5-9 7-8 × 3-6
Corolla lower median lobe size (mm) 7-13 × 3-7 8-18.5 × 5-10 8-10 × 4-6.5
Spur length (mm) 14-22 15-37 20-30
Flowering time June to October, with
summer rosette
All year, with winter and
summer rosettes
April to May with
winter rosette
Habitat Gypsum soils in xeric
scrublands
Limestone rock walls, soils in
xeric scrublands, igneous rock
walls in pine-oak forest, cloud
forest, tropical deciduous forest
Igneous rock walls
in oak forest
Table 1. Morphological comparison among Pinguicula gypsicola, P. moranensis, and P. tlahuica.
Conservation status. Pinguicula tlahuica is known only from two localities. It grows along a few ravines on igneous
rock walls. GeoCAT calculated an AOO of 12 km2. According to the IUCN Red List Categories and Criteria, we
preliminary recommend the category of Endangered (EN), criterion B2ab(iii).
Phenology. The summer rosettes have been observed from May to September. In contrast, the winter rosettes appear
from September to May. The plants bloom from April to May when the winter rosette is present.
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Etymology. The specic epithet honors the Tlahuica ethnical people. The tlahuicas inhabit some villages in Ocuilan
de Arteaga, State of México (Álvarez Fabela 2006).
Additional specimens examined. Mexico, Estado de México, municipio Ocuilan de Arteaga, Barranca y mirador Peña
Redonda, 2,185 m snm, 18° 57’ 57.3” N, 99° 24’ 57.9” W, 29 September 2021, A. Rodríguez et al. 8466 (IBUG, IEB,
MEXU); Parque Tlatucapa, Peña Redonda, 2,185 m, 18° 57’ 57.2” N, 99° 24’ 59” W, 3 September 2022, J. López-Pérez
& G. Munguía-Lino 589 (IBUG, IEB, MEXU). Morelos, Cuernavaca, Barranca cerca del Tecolote, antigua vía de madera
hacia Bella Vista del Monte, May 1955, E. Lyonnet s/n (MEXU, two sheets MEXU-699454 and MEXU-699473).
Species of Pinguicula in the TMVB. There are 16 species of Pinguicula recorded along the TMVB (Table 2, Figures
3, 4). Pinguicula crassifolia, P. michoacana, P. tlahuica, and P. zamudioana are exclusive to this morphotectonic
province (Figures 3, 4). The Pinguicula species along the TMVB can be identied as follows:
1. Corolla isolobate to subisolobate, the superior and inferior lips lobes are almost equal….…..….…..….…..….….. 2
2. Annual plants, with a single type of leaves (homophyllous); corolla lilac or white, palate diminute; tube with purple
veins……………………….....…………………….….………………………………………………… P. lilacina
2. Perennial plants, with two types of leaves during the annual cycle (heterophyllous); corolla white, occasionally with
violet margin, palate absent; tube with green veins……………………………………………………………….. 3
3. Corolla tube geniculate .......................................................................................................................... P. acuminata
3. Corolla tube straight ................................................................................................................................................. 4
4. Rupiculous plants; winter rosette epigeal, leaves entire, blade pubescent; summer leaves entire……….. P. agnata
4. Terrestrial plants; winter rosette hypogeal, leaves ciliate at the base, blade glabrous; summer leaves ciliate at
the base……............................................................................................................................................................ 5
5. Calyx accrescent, covering the capsule at maturity ………........................................................................ P. casperi
5. Calyx not accrescent, nor covering the capsule at maturity ..................................................................... P. parvifolia
1. Corolla bilabiate, with clear distinction between the superior and inferior lip lobes …..................................…..... 6
6. Annual plants; owers 3-7 mm long (including the spur); corolla lobes crenate or cleft……….....… P. crenatiloba
6. Perennial plants; owers larger than 10 mm (including the spur); corolla lobes entire, emarginate or erose….….. 7
7. Homophyllous plants, winter and summer rosettes undifferenciated during the annual cycle.................................. 8
8. Corolla white, lobes emarginate or erose, with evident purple veins ………..….. ................................P. emarginata
8. Corolla pink, lobes entire, with incospicuos veins or the same color as the lobes…............................. P. zamudioana
7. Heterophyllous plants, winter and summer rosettes differentiated during the annual cycle….................................. 9
9. Corolla red to purple-red; tube evident; spur equal or larger than the tube…....….................................. P. crassifolia
9. Corolla blue, purple, pink or violet; tube diminute; spur larger than the tube……...………................................... 10
10. Summer leaves linear-spatulate…........................................................................................................... P. tlahuica
10. Summer leaves cuneate, oblong, elliptic to suborbicular....................................................................................... 11
11. Summer leaves ciliate at the base………………………………….…………..………..…................................. 12
12. Winter rosette subhypogeal, leaves entire………………………..………….…................................. P. elizabetiae
12. Winter rosette hypogeal, leaves ciliate at the base…………………………………………................................. 13
13. Winter rosette covered by a layer of dry membranous leaves, leaves 25-86, lanceolate…................. P. oblongiloba
13. Winter rosette without dry membranous leaves, leaves 20-40, ovate-lanceolate………. ..................P. michoacana
11. Summer leaves entire..…………………………...………...………………………………............................... 14
14. Winter rosette epigeal, laxa; owers 2.4-2.8 cm long (including spur); corolla pink to whitish-purple, whit a yellow
macula at the throat………….……….................................................................................................... P. esseriana
14. Winter rosette epigeal to hypogeal, compact; owers 2.5-6 cm long (including spur); corolla purple, whit a white
macula at the throat …..……………………………….……………………......................................................... 15
15. Winter rosette epigeal to subhypogeal, covered by dry membranous leaves....................................... P. moranensis
15. Winter rosette hypogeal, without dry membranous leaves................................................................. P. macrophylla
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Species richness distribution of Pinguicula along the TMVB. The species richness distribution analyses indicated that
Hidalgo, the State of México and Michoacán (six species each), and the pine-oak forest (10 species) were the richest
states and vegetation type (Figure 5A, B, Table 2). While, Mexico City, Morelos, Puebla, Querétaro, and Tlaxcala
registered two species each. Pinguicula acuminata, P. casperi, P. crassifolia, P. crenatiloba, P. emarginata, P. lilaci-
na, P. moranensis, P. oblongiloba, P. parvifolia, and P. tlahuica were found in pine-oak forest. Only, P. moranensis
was found in the tropical evergreen forest.
Along the TMVB, the species of Pinguicula appeared from 759 m asl to 3,427 m asl (Figure 5C), but these were
found mainly between 1,500-1,999 m asl (Figure 5D). Pinguicula moranensis had the widest elevation distribution
range (996-3,427 m asl, Figure 5C). Whereas, P. michoacana had the narrowest elevation distribution range (1,828-
1,852 m asl, Figure 5C). Furthermore, P. moranensis reached the highest elevation (3,427 m asl, Figure 5C) and P.
lilacina had the lowest elevation (759 m asl, Figure 5C).
The two cell grid sizes recovered different areas with high species values on the Eastern and Western sectors of
the TMVB (Figure 6). The analysis with cells of 0.21 × 0.21° rescued one cell with the highest species richness value
in the Eastern sector (Figure 6A). On the other hand, the 0.24 × 0.24° cell analysis highlighted two richest cells, one
on the Eastern and the other in the Western sectors (Figure 6B).
Discussion
Taxonomic treatment. Pinguicula tlahuica was rst collected in 1955 in the vicinity of Bella Vista del Monte, munici-
pality of Cuernavaca, Morelos by E. Lyonnet. The second author searched for the plants in this locality from 2005 to
2016, but never found them. During a eld expedition in 2021, it was rediscovered and collected in the vicinity of
Specie State Vegetation type
P. acuminata Benth. CdMx, Hgo, Méx, Mich, Qro,
Tlax
Pof, Xs, G
P. agnata Casper Hgo Xs
P. casperi H.D.Juárez & Zamudio Jal Pof
P. crassifolia Zamudio*Hgo Pof
P. crenatiloba DC. Jal, Méx, Mich, Nay Pof, Tdf
P. elizabethiae Zamudio Hgo Xs
P. emarginata Zamudio & Rzed. Pue, Ver Pof, Cf
P. esseriana B.Kirchn. Hgo Xs
P. lilacina Schltdl. & Cham. Nay, Ver Pof, Cf
P. macrophylla Kunth Gto Tdf
P. michoacana Zamudio & H.D.Juárez*Mich Tdf
P. moranensis Kunth CdMx, Gto, Hgo, Méx, Mich,
Mor, Pue, Qro, Tlax, Ver
Pof, Cf, Tdf, Tef, Xs, G
P. oblongiloba A.DC. Gto, Jal, Méx, Mich Pof, Tf, Tdf, G
P. parvifolia B.L.Rob. Jal, Méx, Mich, Mor, Nay Pof, Tf, Tdf
P. tlahuica López-Pérez & Zamudio*Méx, Mor Pof
P. zamudioana H.D.Juárez & Muñiz-Castro*Jal Tdf
Table 2. Species list and distribution of Pinguicula along TMVB. (*) Exclusive species of TMVB. States: CdMx) Mexico City; Gto)
Guanajuato; Hgo) Hidalgo; Jal) Jalisco; Méx) State of México; Mich) Michoacán de Ocampo; Mor) Morelos; Nay) Nayarit; Pue) Pue-
bla; Qro) Querétaro de Arteaga; Tlax) Tlaxcala; Ver) Veracruz de Ignacio de la Llave. Vegetation type: G) Grassland; Cf) Cloud forest;
Tef) Tropical evergreen forest; Pof) Pine-oak forest; Tf) Thorn forest; Tdf) Tropical deciduous forest; Xs) Xeric scrubland.
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Ocuilan de Arteaga, State of México. The dimorphic leaves arranged in summer and winter rosettes, the blue-violet
and bilabiate corollas, the short infundibuliform tube, and the long spur place the new taxon within P. subg. Pinguicula
section Orcheosanthus A.DC. (Candolle 1844). Within this section, P. tlahuica is similar to P. moranensis and P.
gypsicola Brandegee by the form and size of the owers, but morphological characters and ecological preferences
set it apart (Table 1). Pinguicula tlahuica differs from P. moranensis by the linear-spatulate and ascendant summer
leaves (vs. elliptic to sub-orbicular and adpressed to the soil), and the owering period with the presence of winter
rosettes (vs. winter and summer rosettes). In addition, it differs from P. gypsicola by the linear-spatulate and entire
at the base summer leaves (vs. linear-lanceolate and ciliate at the base), and niche preferences. Pinguicula tlahuica
grows on igneous rock walls in the oak forest, whereas P. gypsicola is found on gypsum soils of the xeric scrubland.
Pinguicula tlahuica adds up to 54 the taxonomic richness of Pinguicula in Mexico.
Species richness distribution and endemism of Pinguicula along the TMVB. The MTZ represents the boundary
between the Nearctic and Neotropical regions (Villaseñor et al. 2020). It includes the main mountainous chains of
Mexico, Guatemala, Honduras, El Salvador, and Nicaragua (De Mendonça & Ebach 2020). The MTZ is a set of mor-
photectonic and physiographic provinces with different ages and origins (Ferrusquía-Villafranca 1993, Mastretta-
Yanes et al. 2015). The orientation of the mountain ranges favors the dispersal of northern elements to the south
and vice versa (Zunino & Halffter 1988). Shimai et al. (2021) explain the evolution within Pinguicula by ancient
geographical expansions and gene ow, and subsequent vicariance with genetic drift. Whereas, Domínguez et al.
(2024) highlight the effects of climatic changes over time in the mountain chains of the MTZ, favoring specia-
tion and persistence, which is reected in the high species richness and endemism of Pinguicula (López-Pérez
et al. 2024).
Within the MTZ, the TMVB connects three major mountain ranges at both ends (Ferrusquía-Villafranca et al.
2007, Ferrari et al. 2012). Consequently, the TMVB represents a center of diversity, endemism, persistence, and
Figure 3. Species distribution map of Pinguicula along the TMVB. Blue line: TMVB limits. Red line: Sector limits. Grey line: State limits.
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Figure 4. Pinguicula species in the TMVB. A) P. acuminata. B) P. agnata. C) P. casperi. D) P. crassifolia. E) P. crenatiloba. F) P. emarginata. G) P. es-
seriana. H) P. lilacina. I) P. michoacana. J) P. moranensis. K) P. oblongiloba. L) P. parvifolia. M) P. zamudioana. A-B, D-E, G-M by Jorge López-Pérez,
C by Sergio Zamudio, and F by Alberto Lozano.
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Figure 5. Species richness distribution of Pinguicula along the TMVB. A) Species richness by state. B) Species richness by vegetation type. C) Boxplot
of distribution by elevation range. D) Species richness by elevation range. In dark green the richest class.
Figure 6. Species richness distribution of Pinguicula along the TMVB by grid cell. A) Cell size of 0.21° × 0.21°. B) Cell size of 0.24° × 0.24°. Blue line:
TMVB limits. Red dot line: Sector limits. Gray line: State limits.
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biogeographic transition of the Mexican biota (Halffter & Morrone 2017). Our results identied the species richness
of Pinguicula centered at both extreme sectors of the TMVB. Contact zones among mountain ranges favored the
species richness and has been observed in other groups of plants. Rodríguez et al. (2018), identied grid cells with
high species richness and endemism values of angiosperms in the Eastern, Central and Western sectors. Meanwhile,
Murillo-Pérez et al. (2022) showed high species richness of Solanum (Solanaceae) in the Eastern and Western sec-
tors. Also, Vargas-Amado et al. (2013) rescued the richness of Cosmos (Asteraceae) in the Western sector. Sosa et
al. (2018), Sosa & Loera (2017), and Sanginés-Franco et al. (2015) located the species richness of vascular plants,
monocot geophytes, and ferns in the Eastern sector. Furthermore, Munguía-Lino et al. (2015) recognized this sec-
tor as the richest in Tigridieae (Iridaceae) species. In addition, this sector was highlighted as the species richest for
Lycianthes (Solanaceae) and Echeandia Ortega (Asparagaceae) (Anguiano-Constante et al. 2018, 2021, Ortiz-Bru-
nel et al. 2021). On the other hand, Ruiz-Sanchez & Specht (2013) correlated the TMVB uplifting with the popula-
tion diversication of Nolina parviora (Asparagaceae). In addition, Sosa et al. (2018) found a high phylogenetic
diversity of Mexican vascular plants in this province. Finally, Romero-Soler et al. (2021) revealed evidence support-
ing the speciation of Bakerantha B.L.Sm. (Bromeliaceae) as a result of the TMVB uplift. All analyses support the
importance of the geodiversity and the complex climatic history of this province which promoted the diversication
of angiosperms, including Pinguicula.
Acknowledgments
We thank the staff of all herbaria for the access to specimens. We are grateful to E. Munguía-Lino for assistance
during eld work. Mollie Harker assisted with the English edition. We thank two anonymous reviewers and Martha
González-Elizondo, associate editor, for helpful comments on the manuscript.
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Associate editor: Martha González Elizondo
Author contributions: JDLP designed the project, conducted the eld work, and analyzed the information; SZ examined the specimen; GML
did eld work and analyzed the information; AR worked in the eld.
Supporting Agencies: This research was supported by the Consejo Nacional de Humanidades, Ciencias y Tecnologías (Conahcyt) with the
scholarship (CVU 1002142). The Universidad de Guadalajara and the Laboratorio Nacional de Identicación y Caracterización Vegetal (La-
niVeg) provided nancial support for eld work.
Conict of interest: All authors wrote the manuscript. The authors declare that there is no conict of interest, nancial or personal, in the infor-
mation, presentation of data and results of this article.
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