Search

Plants and insects are two of the more diverse and abundant organisms in terrestrial ecosystems. The fossil record of plant-insect interactions offers crucial insights into the coevolutionary dynamics between these groups, shedding light on the intricate relationships that have shaped terrestrial ecosystems. The study of fossil interactions is especially relevant in mid-Cretaceous ecosystems, a time of dramatic changes in the composition of floras and, consequently, in plantinsect relationships. Here, we describe the first suite of plant-insect interactions from the mid-Cretaceous of Mexico. We studied 554 plant fossils from the El Chango Lagerstatte (Cintalapa Formation, Chiapas, Mexico), including vegetative (leaves) and reproductive structures (fruits and seeds). The flora was dominated by gymnosperms (89.3%) followed by angiosperms (10.7%); other groups, such as pteridophytes and bryophytes, were absent. In total, 5.4% of the plant specimens hosted some damage. Angiosperms (all broad-leafed forms), despite being much less common than gymnosperms, expressed more evidence of damage by herbivores (35.6% of specimens damaged). In contrast, the narrow-leafed gymnosperms, the dominant group in the flora, hosted a much lower proportion of herbivory damage (1.8% of specimens damaged). The diversity of damage types (DTs) was relatively low: 14 DTs were identified, corresponding to seven FFGs, including margin feeding, hole feeding, surface feeding, piercing and sucking, oviposition, galling, and mining. Comparison with the other midCretaceous plant-insect assemblages reveals a similar richness of DTs for angiosperms but a lower richness and diversity of DTs on gymnosperms from El Chango. These results indicate preferential herbivory on angiosperms (rather than on the available gymnosperms in the assemblage) by terrestrial arthropods during a period of major changes in the structure of terrestrial ecosystems. However, it is challenging to resolve whether this apparent preference is because insects particularly targeted angiosperms or if the herbivores simply targeted broad leaves in general, since most of the available gymnosperms from El Chango are scale-leafed forms. [ABSTRACT FROM AUTHOR]

Premise: Alismataceae, a sub‐cosmopolitan family with ca. 17 genera and 113 species, is a large group of aquatic plants. Compression/impressions and bioinclusions of reproductive parts in amber support the documentation of the lineage in low‐latitude North America. In Mexico, fossil aquatic plants have been infrequently documented. The new reproductive structures exhibit characteristics of Alismataceae, whose fossil record is mainly documented in the northern hemisphere through of fruits and seeds. Methods: We described and compared 150 samples of reproductive structures preserved as impressions/compressions from the Oligocene Los Ahuehuetes locality in the state of Puebla, and two bioinclusions from the Miocene amber of Simojovel de Allende in the state of Chiapas, Mexico with extinct and extant taxa. Using a parsimony analysis based on 29 floral characters of 17 extant genera of the Alismataceae, we evaluated the relationship between the fossil material and potential living relatives. Results: We discovered a new genus Nichima based on a perfect, actinomorphic flower with an expanded receptacle, three persistent sepals with multiple vasculatures, delicate and caducous petals, six stamens, and a gynoecium composed of three to more superior carpels, maturing into achenes. These characteristics resemble flowers of Alismataceae. Nichima represents an extinct member of the family, with two new species described here, Nichima magalloniae L. Hern., Cevallos‐Ferriz et Hernández‐Damián sp. nov. and Nichima gonzalez‐medranoi L. Hern., Cevallos‐Ferriz et Hernández‐Damián, sp. nov. Their phylogenetic position suggests affinity with a clade that includes Baldiella, Echinodorus, and Alisma. Conclusions: Reproductive structures from the Cenozoic of Mexico support the identification of a new extinct genus, Nichima, evidencing the extensive history of Alismataceae in North America's low latitudes and suggesting a southern extension of the boreotropical flora. [ABSTRACT FROM AUTHOR]

The fossil flora of the Matzitzi Formation, is a fluvial unit of late Paleozoic age exposed in southern Mexico, has been studied since the last century; however, the discovery of new plant elements during the last decade imposes a reevaluation of two aspects that have always been the subject of debate: the depositional age of the unit and the taxonomy of its paleoflora. The objective of the present work is to report new paleofloral records from two areas of the Matzitzi Formation as well as their chronological implications. The study sites are named Carretera and Coatepec. Nineteen genera and 11 species have been identified in beds from the Carretera site, whereas 23 genera and 16 species in beds from the Coatepec site. The analysis of floral assemblages of both sites shows that they share 49% of taxa. Ovopteris , Lesleya , Lobatopteris, and Trigonocarpus are unique to the Carretera site, while Coatepec is characterized by the presence of cf. Bjuvia, Schizoneura, and Velascophyllum. When analyzing the greatest ranges of the paleoflora awareness for the Carretera site indicates that deposition of these beds took place in a time interval that may span between Pennsylvanian and lower Permian. On the other side, the floral assemblage recovered from the Coatepec site indicates that the hosting beds were deposited in upper Permian time. U–Pb detrital zircon geochronology indicates that the maximum depositional age of the fossiliferous beds at the Carretera and Coatepec sites are of 276 ± 15 Ma and 254 ± 11 Ma, respectively. The integration of the paleontological and geochronological data obtained in this work suggests that the analyzed floral assemblage recovered from the Carretera site is of Kungurian age, whereas the one from the Coatepec site is of Lopingian age. Alternatively, we explore the possibility that deposits that are presently grouped within the Matzitzi Formation could be the vestiges of different fluvial cycles associated with different tectonic settings. Finally, the work on this unit has not finished, since there are still localities where its flora and age are still unknown. • Two age proposals are made for the Matzitzi Formation, Cisuralian and Lopingian • The Carretera locality presents a Cisuralian deposit age • The Coatepec locality presents a Lopingian deposit age • The Carretera locality presents unique taxa such as Lesleya and Lobatopteris • The Coatepec locality presents unique taxa such as Schizoneura and Velascophyllum [ABSTRACT FROM AUTHOR]

Mesozoic ferns from Mexico have been the subject of serious academic endeavours since the beginning of the 20th Century, to understand these plants at the time of their peak diversity. Most findings have been made in a set of Middle Jurassic Basins of the Mixtec Terrain in the Oaxaca State. However, fossil ferns are scarce in other assemblages, so further identification of this group has been infrequent. Here we describe six new and recently collected fossil plants from the Middle Jurassic Otlaltepec Formation, Puebla. Based on their fertile and vegetative fronds, we propose the new genus Paralophosoria Morales-Toledo, Mendoza-Ruiz & Cevallos-Ferriz, gen. nov. in the Dicksoniaceae, represented by Paralophosoria jurassica, Morales-Toledo, Mendoza-Ruiz & Cevallos-Ferriz, sp. nov., and identify the following genera: cf. Aspidistes, Sphenopteris, Spiropteris. A fern with uncertain affinities was also described. This work contributes to the understanding of fern diversity in low latitudes during the Middle Jurassic in Mexico. [ABSTRACT FROM AUTHOR]

The Anticlinorium of Huayacocotla has several outcrops of geological and paleontological importance. However, reports of localities with paleoflora have been scarce so far. In this study, we report three new localities in the Cisuralian, the diversity and composition of which lead us to propose that the paleoflora may have been derived from vegetation that grew in an arid environment with seasonal wetness. The plant remains from the localities of Papaxtla and Calnali are highly transported and their diversity indicates the presence of several groups of plants that were shared with the La Virgen locality, which yielded the best preserved plant fossils. Changes in paleoenvironmental conditions indicate that the preservation of the flora was affected by the tectonic evolution of the region associated with sea level changes. The data presented here increase our knowledge of both the Cisuralian fossil flora and paleoenvironment in the south-central region of the Huayacocotla Anticlinorium, Hidalgo state. [ABSTRACT FROM AUTHOR]

The Late Campanian (Late Cretaceous), upper part of the El Disecado Member, El Gallo Formation, Baja California, México, preserves a rich fossil assemblage of microvertebrates and macrovertebrates, silicified logs, macroscopic plant remains, and pollen that was likely deposited as the distal part of a subaerial fan. The unit was episodic and high energy, with its salient features deriving from active river channels and sheet, debris-flow deposits. Landscape stability is indicated by the presence of compound paleosol horizons, containing Fe2O3 mottling in B horizons, cutans, and calcium carbonate concretions. All of these features indicate wet/dry cyclicity in subsurface horizons, likely attributable to such cyclicity in the climate. Drainage was largely to the north and to a lesser extent, the west; however, some current flow to the south and east is preserved which, in conjunction with the proximal location of marginal marine deposits, suggest the influence of tides in this setting. The fossil vertebrates preserved in this part of the El Disecado Member are almost exclusively allochthonous, preserved as disarticulated isolated clasts in hydraulic equivalence in the braided fluvial system. A relatively diverse micro vertebrate assemblage is preserved, the largest components of which are first, dinosaurs, and second, turtles. Non-tetrapod fossils are relatively uncommon, perhaps reflecting an absence of permanent standing water in this depositional setting. Here we report a high-precision U-Pb date of 74.706 + 0.028 Ma (2σ internal uncertainty), obtained from zircons in an airfall tuff. The tuff is located low within the sequence studied; therefore, most of the sedimentology and fossils reported here are slightly younger. This date, which improves upon previously published 40Ar/39Ar geochronology, ultimately allows for comparison of these El Gallo faunas and environments with coeval ones globally. Primary stable isotopic nodules associated with roots in the paleosols of the terrestrial portion of the El Disecado Member are compared with ratios from similar sources from coeval northern and eastern localities in North America. Distinctive latitudinal gradients are observed in both δ13C and δ18O, reflecting the unique southern and western, coastal geographic position of this locality. These differences are best explained by differences in the floras that populated the northern and eastern localities, relative to the southern and western floras reported here. [ABSTRACT FROM AUTHOR]

The Olmos Formation (upper Campanian) is located in the Sabinas Basin in northern Mexico. It represents a deltaic-fluvial system, and it is known by its abundance of fossil plants mainly represented by leaves and woods. In this contribution, we describe angiosperm fossil leaves, related to ?Violaceae. The new fossil genus has pinnate venation, with a major secondaries festooned semicraspedodromous, tertiary venation opposite percurrent, quaternary veins irregular reticulate, margin crenulated with tooth terminating in a glandular tissue, and fimbrial vein present. This mosaic of characteristics supports the creation of a new genus and species, Mascogophyllum elizondoa Centeno-González, Porras-Múzquiz et Estrada-Ruiz (?Violaceae). This record could be the oldest of the family; also, a new family is added to the very diverse fossil flora record that established during the Cretaceous in the northern of Mexico. • The Olmos Formation (upper Campanian) contains one of the most diverse fossil floras in the continent. • Fossil leaves from Olmos Formation were described and identified. • We describe a new fossil genus resembles to the ?Violaceae family. [ABSTRACT FROM AUTHOR]

A fossil palm flower in Late Oligocene to Early Miocene amber deposits of Chiapas, Mexico, is described as the new species Colpothrinax chiapensis. The flower is perfect and complete, with a calyx tube bearing 3 small, triangular lobes, and 3 ovate-lanceolate, spreading or recurved petals that are connate basally into a shallow tube. The 6 stamens are attached at the mouth of the corolla tube; their slender, subulate filaments are widened basally, slightly connate, and bear large, versatile, laterally dehiscent anthers. The ovary, loosely enclosed in the corolla tube, is composed of 3 closely adjacent, separate carpels. The united style is three-grooved, well-exserted, and slightly shorter than the filaments, with an acute tip and smooth, non-papillate stigma. The 3 modern species of Colpothrinax differ from the fossil in having the filaments shorter, more widely tapering, and united basally to form a better developed staminal tube. [ABSTRACT FROM AUTHOR]

Abstract: Plant macrofossils from 38 packrat middens spanning the last ~33,000cal yr BP record vegetation between ~650 and 900m elevation along the eastern escarpment of the Sierra San Pedro Mártir, northern Baja California. The middens span most of the Holocene, with a gap between ~4600 and 1800cal yr BP, but coverage in the Pleistocene is uneven with a larger hiatus between 23,100 and 14,400cal yr BP. The midden flora is relatively stable from the Pleistocene to Holocene. Exceptions include Pinus californiarum, Juniperus californica and other chaparral elements that were most abundant >23,100cal yr BP and declined after 14,400cal yr BP. Despite being near the chaparral/woodland-desertscrub ecotone during glacial times, the midden assemblages reflect none of the climatic reversals evident in the glacial or marine record, and this is corroborated by a nearby semi-continuous pollen stratigraphy from lake sediments. Regular appearance of C4 grasses and summer-flowering annuals since 13,600cal yr BP indicates occurrence of summer rainfall equivalent to modern (JAS average of ~80–90mm). This casts doubt on the claim, based on temperature proxies from marine sediments in the Guaymas Basin, that monsoonal development in the northern Gulf and Arizona was delayed until after 6200cal yr BP. [Copyright &y& Elsevier]

Abstract: Thin-bedded and millimetrically laminated platy marly limestone quarried near Vallecillo, north-eastern Mexico, contains abundant excellently preserved marine fossils. Planktic foraminifers, inoceramids, and ammonites occur throughout the 7.7-m-thick section of this plattenkalk and provide a precise and detailed biostratigraphic zonation from the uppermost Cenomanian to early Turonian, with a mixed assemblage of Tethyan and Western Interior Seaway faunal elements. Five species of inoceramids are present and described herein: Inoceramus pictus pictus, Mytiloides hattini, M. puebloensis, M. goppelnensis, and M. kossmati. The faunal characteristics of the Vallecillo fossil assemblage combined with the monotonous lithology are favourable attributes for correlation with the GSSP at Pueblo, Colorado, and the Eastbourne section in southern England. The first appearances (FAs) of Watinoceras and Mammites nodosoides are considered approximately isochronous and thus suited for long-distance correlation. In contrast, the FAs of Pseudaspidoceras flexuosum, Fagesia catinus, and Helvetoglobotruncana helvetica are clearly diachronous. The range of M. kossmati needs further evaluation. [Copyright &y& Elsevier]

Abstract: In order to establish the general environmental conditions under which the plants of the El Cien Formation grew during the Miocene, wood anatomical features from several extant ecological categories (southern California flora) and communities (Brazil, Mexico and Suriname) as well as those of the El Cien paleocommunity were analysed using different statistical approaches. We find a significant correlation between 42 characters of 199 species and 11 climate variables which suggests a close association of wood characters with temperature, whereas characters such as diameter, frequency, and grouping of vessels are more closely related to evaporation. The expression of various wood characters depends on more than one climate variable. There are no doubts regarding the tropical affiliation of the El Cien fossil flora but water availability and seasonality of the system are less clear. Principal component and cluster analyses of two different datasets (423 species, 9 characters and 223 species, 32 characters) suggest that the physiognomy of the fossil assemblage of El Cien was highly efficient in water transport, but also highly vulnerable to embolisms. Characters such as vessel diameter, frequency and grouping suggest proximity to a tropical rain forest, whereas the proportion of ring semi ring porous woods brings the El Cien paleoflora closer to forests with slightly xeromorphic physiognomy, probably a tropical deciduous or semi-deciduous forest. This condition is paralleled with the taxonomic composition of the El Cien fossil plants since their Nearest Living Relatives (NLR) can be referred to both humid or more (seasonally) dry environments. Derived regression analysis models suggest that the paleoflora prospered under conditions with an evaporation regime similar to that of the tropical rain forest. [Copyright &y& Elsevier]

Recently discovered fossil flowers from the Cretaceous Cerro del Pueblo and flowers and fruits from the Oligocene Coatzingo Formations are assigned to the Rhamnaceae. The Cretaceous flower, Coahuilanthus belindae Calvillo-Canadell and Cevallos-Ferriz, gen. et sp. nov., is actinomorphic with fused perianth parts forming a slightly campanulate to cupulate floral cup, with sepals slightly keeled and spatulate clawed petals. The Oligocene fossils include Nahinda axamilpensis Calvillo-Canadell and Cevallos-Ferriz, gen. et sp. nov. (characterized by its campanulate bisexual flower with stamens opposite, adnate to and enfolded by petals; and with the ovary ripening into a drupe), and a winged fruit assigned to Ventilago engoto Calvillo-Canadell and Cevallos-Ferriz, sp. nov. The flowers and drupe features indicate closer affinity to Zizipheae and/or Rhamneae, while the single samaroid fruit suggests the presence of Ventilagineae. However, the unique character combination in the fossil flowers precludes placing them in extant genera. Nevertheless, the history of the family is long and can be traced back to the Campanian. A detailed phylogenetic revision of the group that uses morphological characters from both extant and fossil plants is needed to better understand the significance of these records as well as other important fossils of the family. [ABSTRACT FROM AUTHOR]

Abstract: Three fossil wood types are described from the Olmos Formation, Coahuila, Mexico. The anatomical characters of two of them enable identification to Malvaceae and Fagaceae, while the affiliation of the third type is uncertain (Fagaceae?). The wood of the Malvaceae fossil plant is characterised by the presence of vessel-ray and vessel-parenchyma pits with reduced borders, larger than the intervascular pits, scanty paratracheal parenchyma, septate fibres and storied structure. This wood type, Javelinoxylon, has been also found in the Maastrichtian Javelina Formation, Texas. Aggregate and uniseriate homocellular rays, apotracheal diffuse and diffuse in aggregates parenchyma, simple perforation plates, vessel-ray pits variable with reduced borders and vasicentric tracheids relate the wood of a second plant to Quercinium. The third wood type, Sabinoxylon pasac Estrada-Ruiz, Martínez-Cabrera et Cevallos-Ferriz, is very similar to some species of Quercinium; however, the presence of heterocellular rays and the almost exclusive presence of scalariform perforation plates make unlikely its relationship with this genus. Since observation of vessel parenchyma and vessel ray pits was not possible, its inclusion in Fagaceae cannot be confirmed. Nevertheless, S. pasac and Quercinium centenoae Estrada-Ruiz, Martínez-Cabrera et Cevallos-Ferriz represent the earliest record of fagaceous plants in Mexico, while the presence of Javelinoxylon weberi Estrada-Ruiz, Martínez-Cabrera et Cevallos-Ferriz extends the geographic distribution of the genus in North America. [Copyright &y& Elsevier]

Abstract: The Teotihuacan Valley, Mexico has been the object of considerable interest because of its importance in the context of human history in America. Although, archeological research has been extensively conducted to understand causes of the decline of Teotihuacan culture, no sufficient scientific evidence has been provided. This paper is focused on paleopedological evidence, especially properties that constitute “soil memory,” in order to reconstruct the spatial distribution of environment variability during the Late Pleistocene and Holocene. Three profiles that include modern soils and buried paleosols were studied in different geomorphic positions: uplands (Cerro Gordo site, CG), lower talus slope/transition to valley bottom (Maseca, MA), and the mouth of the Valley, at the ancient border of the former Texcoco lake. This last site is near Tepexpan (TE) where some of the oldest human remains in Mexico were recovered. The oldest paleosol is at CG at 3000ma.s.l. It is dated at 22,000yrBP and exhibits a truncated profile with a very well developed Bt horizon, dominated by kaolinite, with phytoliths of C3 plants. All of its features are related to a humid, probably warm environment. It was classified as a Luvisol. This paleosol is buried by another Luvisol, dated at 13,000yrBP, with morphological characteristics similar to the previous soil, although clay mineralogy consists mostly of halloysite and a higher percentage of C4-plant phytoliths is apparent. In MA the oldest paleosol was not recognized. It is probable that the two paleosols found in CG merge into one at MA, which shows strong redoximorphic features, but high percentages of C4-plant phytoliths and halloysitic clays. At the TE site paleosols are less developed Fluvisols. Modern soil cover also varies in relation to its geomorphic position. In CG it is a Phaeozem, while in MA and TE present day soils have carbonate accumulation. We interpret prevailing conditions during the Last Glacial Maximum in the Teotihuacan valley to be humid, with a tendency towards drying at the end of Pleistocene. Dry conditions prevail in the valley today. [Copyright &y& Elsevier]

Microfossils associated with stromatolites in the Upper Cretaceous (Campanian–Maastrichtian) are preserved in chert layers of the Tarahumara Formation that crop out at the Huepac Chert locality in Sonora, Mexico. A high diversity of microfossils was reported in a previous publication and ten of these are identified here as Cyanophyta (Calothrix estromatolitica, Eucapsis jacquesii, Gloeocapsa taverae, Microcystis cretacica, and Spirulina noveloi), Chlorophyta (Chlorella godinezii, and Tetraedron roldanii), and Bacillariophyta (Fragilaria tarahumara, Melosira huepacensis, and Tabellaria sonorensis), based on their similarities in form, shape, size, and three dimensional arrangement when compared to extant algae. Benthonic or planktonic habits of the extant species are thought to be similar to those of the fossils; therefore, a few could have participated in the build up of the stromatolites in non-marine, most probably freshwater environments. These fossils document the diversity of microorganisms in freshwater environments during the Late Cretaceous in northern Mexico, which include some of the most ancient freshwater diatoms. [Copyright &y& Elsevier]

Investigates the origin and environmental setting of ancient agriculture at San Andres in Tabasco, Mexico. Preservation of plant macrofossils in dry caves; Role of humid tropical areas of Mesoamerica in plant domestication; Collection of soil samples from cultural features.

The Jurassic flora of Mexico represents a key element for the knowledge of the paleoflora on the western margin of equatorial Pangea because of its abundance and diversity. Bennettitales were the dominant group and are represented by leaves and reproductive organs in Jurassic outcrops from southern Mexico. This group has been historically recorded in seven lithostratigraphic units in southern Mexico in a range from the Toarcian to the Callovian. These reports have focused on morphological and taxonomical aspects for the obtention of paleofloristic listings by locality but do not provide environmental data or have any impact on biostratigraphic or phytogeographic analyses. The highest number of localities in Mexico has been reported in the state of Oaxaca, where plant fossils are more abundant and better preserved in comparison with localities of Guerrero, Puebla, Veracruz, and Hidalgo states. Therefore, in order to reinforce the paleofloristic knowledge of southern Mexico, the present study documents the diversity of Bennettitales in northwestern Oaxaca region, which is composed of 11 fossil-genera and 41 fossil-taxa, included 30 valid species and 11 species that need taxonomic revision. We provide the description of a new species, Williamsonia sanjuanensis sp. nov., new findings of Williamsonia nathorstii, and the first record of Bennetticarpus for southern Mexico. We also describe fossiliferous outcrops of the Zorrillo and Zorrillo/Taberna undifferentiated formations and propose their sedimentary environments. In addition, we provide a proposal of one biozone based on Bennettitales. Finally, we recognize six spatio-temporal distribution patterns for this plant group in northwestern Oaxaca. These new data add to a growing set of information on the Jurassic flora of Mexico and allow to substantiate the paleobotanic importance of southern Mexico within the region of North America. • A new species of Williamsonia is described from the southern Mexico. • So far, 41 taxa of Bennettitales have been reported in southern Mexico. • We provide the first proposal of a biozone based on Bennettitales for the northwestern Oaxaca. • We recognize six spatio-temporal distribution patterns of Bennettitales in northwestern Oaxaca. [ABSTRACT FROM AUTHOR]

Recent fossil findings of well-preserved plants in deposits of the Cabullona Group (Campanian-Maastrichtian) indicate that in this region grew an abundant flora. In order to contribute to the knowledge of its paleodiversity, three silicified trunks more than 4 m in length and a stump of 72 cm high discovered close to the town of Fronteras, in sandstones of Campanian age, are described and identified. The fossil wood of these specimens is pycnoxylic and their anatomical characteristics indicate they are typical Cupressinoxylon. Although there is slight anatomical variation among these fossil trunks, they were all included in the same species. The wood anatomy of the fossils does not have a particular affinity to any extant taxa, and among fossil taxa compares closely to Cupressinoxylon , therefore it was assigned to a new species, Cupressinoxylon manuelii Rios-Santos et al. The fluvial and lacustrine deposits suggested by the rocks where the logs were found coincide with the ecological conditions proposed for the growth and reproduction environments these woody plants prefer. To date, another wood pattern has not been found. Although other micro and macro-fossils have been found in nearby locations is probable that this cupressaceous species represent a dominant element in the canopy of the vegetation, which needs more studies in order to propose a full reconstruction. • The first record of Cupressinoxylon in Mexico (Cabullona Group). • Cupressaceous woods reinforce the described paleoenvironments for the Fronteras area. • The new taxon contributes to the Late Cretaceous vegetation reconstruction in northwestern Sonora. • The new specimens add to cretaceous plant diversity in low latitude North America. [ABSTRACT FROM AUTHOR]

A. Typical specimen of a plant of the genus Ceratozamia. B. Ontogenetic transformation by estimating the difference in the value of the leaflets shape index between seedlings and adults. C. Phylogeny of Ceratozamia species. In each terminal typical leaflets of each species are presented. • Comprehensive phenotypic assessment of populations-species of a cycad genus. • Molecular phylogeny supports two clades: ' miqueliana' and ' mexicana '. • Ceratozamia was originated at the S of Mexico and diversified in the last 3 Mya. • Empirical evidence of punctuated evolution in the lineages encompassed by Ceratozamia. • Ontogeny also traces the evolutionary history of the Ceratozamia species. Evidence suggests that past climatic fluctuations affected speciation of extant cycads. However, empirical genetic and morphological evidence explaining patterns and processes of species diversification are scarce. There are some explanations for the origin and evolution of the genus Ceratozamia , but with inconclusive results. To elucidate the evolution of Ceratozamia , we used genetic and phenotypic sources as empirical data, which were applied in a 'proximate-ultimate' framework (ecological and evolutionary scale, respectively). Our results suggested that the evolutionary mechanisms of speciation were shaped by deterministic (natural selection-adaptation) driven by climatic conditions associated to water stress, and probably enhanced by stochastic processes (gene drift and inbreeding). In general terms, punctuated evolution models were those that best explained the patterns of speciation throughout the phylogenetic history of the lineages encompassed in the genus Ceratozamia. Finally, we provide empirical evidence on the tempo and mode of the evolution of a 'living plant fossil'. [ABSTRACT FROM AUTHOR]