Evolutionary trends of reproductive phenotype in Cycadales: an analysis of morphological evolution in Ceratozamia.

BACKGROUND AND AIMS: The size and shape of reproductive structures is especially relevant in evolution because these characters are directly related to the capacity of pollination and seed dispersal, a process that plays a basic role in evolutionary patterns. The evolutionary trajectories of reproductive phenotypes in gymnosperms have received special attention in terms of pollination and innovations related to the emergence of the Spermatophytes. However, variability of reproductive structures, evolutionary trends and the role of environment in the evolution of cycad species have not been well documented and explored. This study considered this topic under an explicitly phylogenetic and evolutionary approach that included a broad sampling of reproductive structures in the genus Ceratozamia. METHODS: We sampled 1400 individuals of 36 Ceratozamia species to explore evolutionary pattern and identify and evaluate factors that potentially drove their evolution. We analyzed characters for both pollen and ovulate strobili within a phylogenetic framework using different methods and characters (i. e., molecular and both quantitative and qualitative morphological) to infer phylogenetic relationships. Using this phylogenetic framework, evolutionary models of trait evolution for strobilar size were evaluated. In addition, quantitative morphological variation and its relation to environmental variables across species were analyzed. KEY RESULTS: We found contrasting phylogenetic signals between characters of pollen and ovulate strobili. These structures exhibited high morphological disparity in several characters related to size. Results of analyses of evolutionary trajectories suggested a stabilizing selection model. In regards to phenotype-environment, the analysis produced mixed results and differences for groups in the vegetation type where the species occur; however, a positive relationship with climatic variables was found. CONCLUSIONS: The integrated approach synthesized reproductive phenotypic variation with current phylogenetic hypotheses and provided explicit statements of character evolution. The characters of volume for ovulate strobili were the most informative, which could provide a reference for further study of the evolutionary complexity in Ceratozamia. Finally, heterogeneous environments, which are under changing weather conditions, promote variability of reproductive structures.

Plant morpho evo-devo.

Evo-devo is often thought of as being the study of which genes underlie which phenotypes. However, evo-devo is much more than this, especially in plant science. In leaf scars along stems, cell changes across wood growth rings, or flowers along inflorescences, plants trace a record of their own development. Plant morpho evo-devo provides data that genes could never furnish on themes such as heterochrony, the evolution of temporal phenotypes, modularity, and phenotype-first evolution. As plant science surges into increasingly -omic realms, it is essential to keep plant morpho evo-devo in full view as an honored member of the evo-devo canon, ensuring that plant scientists can, wherever they are, generate fundamental insights at the appropriate level of biological organization.

Community partnerships are fundamental to ethical ancient DNA research.

The ethics of the scientific study of Ancestors has long been debated by archaeologists, bioanthropologists, and, more recently, ancient DNA (aDNA) researchers. This article responds to the article "Ethics of DNA research on human remains: five globally applicable guidelines" published in 2021 in Nature by a large group of aDNA researchers and collaborators. We argue that these guidelines do not sufficiently consider the interests of community stakeholders, including descendant communities and communities with potential, but yet unestablished, ties to Ancestors. We focus on three main areas of concern with the guidelines. First is the false separation of "scientific" and "community" concerns and the consistent privileging of researcher perspectives over those of community members. Second, the commitment of the guidelines' authors to open data ignores the principles and practice of Indigenous Data Sovereignty. Further, the authors argue that involving community members in decisions about publication and data sharing is unethical. We argue that excluding community perspectives on "ethical" grounds is convenient for researchers, but it is not, in fact, ethical. Third, we stress the risks of not consulting communities that have established or potential ties to Ancestors, using two recent examples from the literature. Ancient DNA researchers cannot focus on the lowest common denominator of research practice, the bare minimum that is legally necessary. Instead, they should be leading multidisciplinary efforts to create processes to ensure communities from all regions of the globe are identified and engaged in research that affects them. This will often present challenges, but we see these challenges as part of the research, rather than a distraction from the scientific endeavor. If a research team does not have the capacity to meaningfully engage communities, questions must be asked about the value and benefit of their research.

Monograph of Ceratozamia (Zamiaceae, Cycadales): an endangered genus.

Ceratozamia (Zamiaceae, Cycadales), is a member one of the most endangered seed plant groups. Species of Ceratozamia grow from near sea level up to 2,100 meters in Mexico and Mesoamerica. We present a modern taxonomic treatment of Ceratozamia, based on fieldwork combined with detailed study of herbarium specimens in and from Mexico and Central America. This new revision is based on incorporation of morphological, molecular and biogeographic data that have been previously published in circumscriptions of species complexes by our group. Detailed morphological descriptions of the 36 species of Ceratozamia are provided and relevant characters for the genus are discussed and described. A majority are endemic to Mexico and are concentrated at high elevations in mountainous areas. Synonymies, lectotypifications, etymologies, taxonomic notes, distribution maps, illustrations and detailed species-level comparisons are included, as well as a dichotomous key for identification of all species. Data on distributional ranges and habitats of all species are summarized. Ceratozamiaosbornei D.W.Stev., Mart.-Domínguez & Nic.-Mor., sp. nov. is described from evergreen tropical forests of Belize and we highlight new populations and distributional ranges for C.subroseophylla Mart.-Domínguez & Nic.-Mor. and C.vovidesii Pérez-Farr. & Iglesias in the Mesoamerican region.

A novelty in Ceratozamia (Zamiaceae, Cycadales) from the Sierra Madre del Sur, Mexico: biogeographic and morphological patterns, DNA barcoding and phenology.

Ceratozamia is a genus of cycads occurring in eastern Mexico and Central America. In this study, we describe a new species from the Pacific region of Mexico in Guerrero state. This locality represents the most northwestern Mexico distribution for the genus. We focus the comparison of this species with the most geographically proximate and phenotypically relevant lineages for this taxon. We followed an integrative taxonomy approach to evaluate the classification of these species, including geographic location, morphology, DNA barcoding and phenology as primary sources of systematic data. Within the morphological dataset, reproductive structures are described in detail and new characters are proposed for microsporophylls. The comparative morphology of these structures facilitated the elucidation of differences in forms and species for identification. The two chosen DNA barcoding markers - namely, the chloroplast genome coding region matK and the nuclear ribosomal internal transcribed spacer (ITS) region - had low divergence, allowing only 61% of species identification, suggesting slow molecular evolutionary rates. Besides employing these three basic sources of evidence, we introduced phenology as additional information for species circumscription. In addition, this work includes a brief review of the genus at the species-level. This is therefore the most recent review for Ceratozamia across its full geographic range (latitudinal and elevational). Overall, this work further contributes to a comprehensive framework for systematic studies in Mexican cycads.

Domestication of aromatic medicinal plants in Mexico: Agastache (Lamiaceae)-an ethnobotanical, morpho-physiological, and phytochemical analysis.

BACKGROUND: Most reports of domesticated plants that involve a domestication gradient or inter-specific hybridization in Mexico have focused on those used as food. This study provides knowledge about these processes in two aromatic medicinal plants, Agastache mexicana (Lamiaceae) and A. m. subsp. xolocotziana, widely used in Mexican traditional medicine for the treatment of gastrointestinal ailments and for their sedative effect. Different populations of A. mexicana along a gradient of domestication are found in the foothills of the Popocatepetl volcano of central Mexico, while in this same area the subsp. xolocotziana grows only in the cultivation, possibly a product of hybridization between A. mexicana and Agastache palmeri. This study links ethnobotanical, morpho-physiological, and phytochemical evidence to document the domestication of both taxa as well as elucidates the possible hybrid origin of the subsp. xolocotziana. METHOD: We analyze three groups of data derived from (1) 80 semi-structured interviews aimed at documenting the selection criteria related to the use and management of A. mexicana; (2) a cultivation experiment under homogeneous conditions, evaluating 21 floral, vegetative, and seed characters (that were important according to ethnobotanical information) in 97 plants corresponding to 13 populations of the taxa under study; and (3) the chemical profiles of the essential oils of these plants by means of a thin-layer chromatography. RESULTS: By linking the three types of evidence, two evolutionary processes are distinguished: (1) A. mexicana occurs in the encouraged-cultivated phases of the domestication gradient and (2) A. m. subsp. xolocotziana may have originated through inbreeding depression or hybridization. These two cultivated plants show a domestication syndrome based upon organoleptic differentiation due to their dissimilar phytochemical composition and gigantism in flowers, seeds, and rhizomes (the last enhancing their asexual reproductive capacity). In addition to this, A. mexicana exhibits more intense floral pigmentation and foliar gigantism while subsp. xolocotziana presents floral albinism and partial seed sterility. CONCLUSION: Two divergent evolutionary processes are reported for the domestication of A. mexicana as a result of the intensification of its use and management. The selection processes of these plants have resulted in alternation of the organoleptic properties based upon the divergence of the phytochemical composition. Also, gigantism has been selected in culturally preferred plant parts and in correlated structures. The preceding characteristics reinforce the joint use of these plants in infusion in Mexican traditionalmedicine for the treatment of gastrointestinal diseases and for their sedative effects.

A User's Guide to Metaphors In Ecology and Evolution.

Biologists energetically debate terminology in ecology and evolution, but rarely discuss general strategies for resolving these debates. We suggest focusing on metaphors, arguing that, rather than looking down on metaphors, biologists should embrace these terms as the powerful tools they are. Like any powerful tool, metaphors need to be used mindful of their limitations. We give guidance for recognizing metaphors and summarize their major limitations, which are hiding of important biological detail, ongoing vagueness rather than increasing precision, and seeming real rather than figurative. By keeping these limitations in mind, metaphors like adaptive radiation, adaptive landscape, biological invasion, and the ecological niche can be used to their full potential, powering scientific insight without driving research off the rails.

The emerging structure of the Extended Evolutionary Synthesis: where does Evo-Devo fit in?

The Extended Evolutionary Synthesis (EES) debate is gaining ground in contemporary evolutionary biology. In parallel, a number of philosophical standpoints have emerged in an attempt to clarify what exactly is represented by the EES. For Massimo Pigliucci, we are in the wake of the newest instantiation of a persisting Kuhnian paradigm; in contrast, Telmo Pievani has contended that the transition to an EES could be best represented as a progressive reformation of a prior Lakatosian scientific research program, with the extension of its Neo-Darwinian core and the addition of a brand-new protective belt of assumptions and auxiliary hypotheses. Here, we argue that those philosophical vantage points are not the only ways to interpret what current proposals to 'extend' the Modern Synthesis-derived 'standard evolutionary theory' (SET) entail in terms of theoretical change in evolutionary biology. We specifically propose the image of the emergent EES as a vast network of models and interweaved representations that, instantiated in diverse practices, are connected and related in multiple ways. Under that assumption, the EES could be articulated around a paraconsistent network of evolutionary theories (including some elements of the SET), as well as models, practices and representation systems of contemporary evolutionary biology, with edges and nodes that change their position and centrality as a consequence of the co-construction and stabilization of facts and historical discussions revolving around the epistemic goals of this area of the life sciences. We then critically examine the purported structure of the EES-published by Laland and collaborators in 2015-in light of our own network-based proposal. Finally, we consider which epistemic units of Evo-Devo are present or still missing from the EES, in preparation for further analyses of the topic of explanatory integration in this conceptual framework.

Taxonomic review of Ceratozamia (Zamiaceae) in the Sierra Madre Oriental, Mexico.

The genus Ceratozamia is revised for the Sierra Madre Oriental in Mexico. This region is one of the biogeographic areas with the greatest diversity of species in this genus. These species are highly variable morphologically and this variability has led to a complex taxonomic history with many synonyms, particularly with reference to C. mexicana. We present a comprehensive taxonomic revision with history of nomenclature and the morphology, relationships, distribution and use of these species. We also introduce a key for their identification, descriptions, full synonymy, nomenclatural notes, etymologies and neotypes as well as taxonomic comments describing relevant taxonomic changes. We recognise fourteen species in this biogeographic province: C. brevifrons, C. chamberlainii, C. decumbens, C. delucana, C. fuscoviridis, C. hildae, C. kuesteriana, C. latifolia, C. mexicana, C. morettii, C. sabatoi, C. tenuis, C. totonacorum and C. zaragozae. This study provides a foundation for future taxonomic work in Neotropical species of Ceratozamia.

Expression of the KNOTTED HOMEOBOX Genes in the Cactaceae Cambial Zone Suggests Their Involvement in Wood Development.

The vascular cambium is a lateral meristem that produces secondary xylem (i.e., wood) and phloem. Different Cactaceae species develop different types of secondary xylem; however, little is known about the mechanisms underlying wood formation in the Cactaceae. The KNOTTED HOMEOBOX (KNOX) gene family encodes transcription factors that regulate plant development. The role of class I KNOX genes in the regulation of the shoot apical meristem, inflorescence architecture, and secondary growth is established in a few model species, while the functions of class II KNOX genes are less well understood, although the Arabidopsis thaliana class II KNOX protein KNAT7 is known to regulate secondary cell wall biosynthesis. To explore the involvement of the KNOX genes in the enormous variability of wood in Cactaceae, we identified orthologous genes expressed in species with fibrous (Pereskia lychnidiflora and Pilosocereus alensis), non-fibrous (Ariocarpus retusus), and dimorphic (Ferocactus pilosus) wood. Both class I and class II KNOX genes were expressed in the cactus cambial zone, including one or two class I paralogs of KNAT1, as well as one or two class II paralogs of KNAT3-KNAT4-KNAT5. While the KNOX gene SHOOTMERISTEMLESS (STM) and its ortholog ARK1 are expressed during secondary growth in the Arabidopsis and Populus stem, respectively, we did not find STM orthologs in the Cactaceae cambial zone, which suggests possible differences in the vascular cambium genetic regulatory network in these species. Importantly, while two class II KNOX paralogs from the KNAT7 clade were expressed in the cambial zone of A. retusus and F. pilosus, we did not detect KNAT7 ortholog expression in the cambial zone of P. lychnidiflora. Differences in the transcriptional repressor activity of secondary cell wall biosynthesis by the KNAT7 orthologs could therefore explain the differences in wood development in the cactus species.

Evolutionary Developmental Biology (Evo-Devo) Research in Latin America.

Famous for its blind cavefish and Darwin's finches, Latin America is home to some of the richest biodiversity hotspots of our planet. The Latin American fauna and flora inspired and captivated naturalists from the nineteenth and twentieth centuries, including such notable pioneers such as Fritz Müller, Florentino Ameghino, and Léon Croizat who made a significant contribution to the study of embryology and evolutionary thinking. But, what are the historical and present contributions of the Latin American scientific community to Evo-Devo? Here, we provide the first comprehensive overview of the Evo-Devo laboratories based in Latin America and describe current lines of research based on endemic species, focusing on body plans and patterning, systematics, physiology, computational modeling approaches, ecology, and domestication. Literature searches reveal that Evo-Devo in Latin America is still in its early days; while showing encouraging indicators of productivity, it has not stabilized yet, because it relies on few and sparsely distributed laboratories. Coping with the rapid changes in national scientific policies and contributing to solve social and health issues specific to each region are among the main challenges faced by Latin American researchers. The 2015 inaugural meeting of the Pan-American Society for Evolutionary Developmental Biology played a pivotal role in bringing together Latin American researchers eager to initiate and consolidate regional and worldwide collaborative networks. Such networks will undoubtedly advance research on the extremely high genetic and phenotypic biodiversity of Latin America, bound to be an almost infinite source of amazement and fascinating findings for the Evo-Devo community.

Intracultural Differences in Local Botanical Knowledge and Knowledge Loss among the Mexican Isthmus Zapotecs.

This study reports on the socio-demographic and locality factors that influence ethnobiological knowledge in three communities of Zapotec indigenous people of the Isthmus of Tehuantepec, Mexico. It uses local botanical nomenclature as a proxy for general ethnobiological knowledge. In each of these communities (one urban and two rural), 100 adult men were interviewed aided with a field herbarium. Fifty had a background in farming, and 50 worked in the secondary or tertiary sector as their main economic activity, totaling 300 interviews. Using a field herbarium with samples of 30 common and rare wild regional species, we documented visual recognition, knowledge of the local life form, generic and specific names and uses (five knowledge levels measuring knowledge depth). The relationship between sociodemographic variables and knowledge was analyzed with simple correlations. Differences between the three communities and the five knowledge levels were then evaluated with a discriminant analysis. A general linear analysis identified factors and covariables that influenced the observed differences. Differences between the groups with different economic activities were estimated with a t-test for independent samples. Most of the relationships found between sociodemographic variables and plant knowledge were expected: age and rurality were positively related with knowledge and years of formal schooling was negatively related. However, the somewhat less rural site had more traditional knowledge due to local circumstances. The general linear model explained 70-77% of the variation, a high value. It showed that economic activity was by far the most important factor influencing knowledge, by a factor of five. The interaction of locality and economic activity followed. The discriminant analysis assigned interviewees correctly to their localities in 94% of the cases, strengthening the evidence for intracultural variation. Both sociodemographic and historic intracultural differences heavily influence local knowledge.

Molecular control of normal and acrocona mutant seed cone development in Norway spruce (Picea abies) and the evolution of conifer ovule-bearing organs.

Reproductive organs in seed plants are morphologically divergent and their evolutionary history is often unclear. The mechanisms controlling their development have been extensively studied in angiosperms but are poorly understood in conifers and other gymnosperms. Here, we address the molecular control of seed cone development in Norway spruce, Picea abies. We present expression analyses of five novel MADS-box genes in comparison with previously identified MADS and LEAFY genes at distinct developmental stages. In addition, we have characterized the homeotic transformation from vegetative shoot to female cone and associated changes in regulatory gene expression patterns occurring in the acrocona mutant. The analyses identified genes active at the onset of ovuliferous and ovule development and identified expression patterns marking distinct domains of the ovuliferous scale. The reproductive transformation in acrocona involves the activation of all tested genes normally active in early cone development, except for an AGAMOUS-LIKE6/SEPALLATA (AGL6/SEP) homologue. This absence may be functionally associated with the nondeterminate development of the acrocona ovule-bearing scales. Our morphological and gene expression analyses give support to the hypothesis that the modern cone is a complex structure, and the ovuliferous scale the result of reductions and compactions of an ovule-bearing axillary short shoot in cones of Paleozoic conifers.

Morphological "primary homology" and expression of AG-subfamily MADS-box genes in pines, podocarps, and yews.

The morphological variation among reproductive organs of extant gymnosperms is remarkable, especially among conifers. Several hypotheses concerning morphological homology between various conifer reproductive organs have been put forward, in particular in relation to the pine ovuliferous scale. Here, we use the expression patterns of orthologs of the ABC-model MADS-box gene AGAMOUS (AG) for testing morphological homology hypotheses related to organs of the conifer female cone. To this end, we first developed a tailored 3'RACE procedure that allows reliable amplification of partial sequences highly similar to gymnosperm-derived members of the AG-subfamily of MADS-box genes. Expression patterns of two novel conifer AG orthologs cloned with this procedure-namely PodAG and TgAG, obtained from the podocarp Podocarpus reichei and the yew Taxus globosa, respectively-are then further characterized in the morphologically divergent female cones of these species. The expression patterns of PodAG and TgAG are compared with those of DAL2, a previously discovered Picea abies (Pinaceae) AG ortholog. By treating the expression patterns of DAL2, PodAG, and TgAG as character states mapped onto currently accepted cladogram topologies, we suggest that the epimatium-that is, the podocarp female cone organ previously postulated as a "modified" ovuliferous scale-and the canonical Pinaceae ovuliferous scale can be legitimally conceptualized as "primary homologs." Character state mapping for TgAG suggests in turn that the aril of Taxaceae should be considered as a different type of organ. This work demonstrates how the interaction between developmental-genetic data and formal cladistic theory could fruitfully contribute to gymnosperm systematics.

AGAMOUS subfamily MADS-box genes and the evolution of seed cone morphology in Cupressaceae and Taxodiaceae.

In this comparative developmental genetics study, we test hypotheses based on fossil and morphological data on reproductive organ morphology and evolution in conifers--specifically, the ovule-bearing organ in Cupressaceae and Taxodiaceae. Genes homologous to the Arabidopsis gene AGAMOUS are expressed in ovuliferous scales of spruces (Picea) throughout development. Previous studies have shown that the AGAMOUS subfamily of MADS-box genes predates the split between angiosperms and gymnosperms, and that these genes have in part conserved functions in reproductive development among seed plants, especially in the specification of identity of the ovule-bearing organs. These data indicate that their expression in conifer families other than Pinaceae might be used as markers for organs homologous to the Pinaceae ovuliferous scale. Here we have isolated putative AGAMOUS orthologs from Cupressaceae and Taxodiaceae and analyzed their expression pattern in seed cones to test for the presence of morphological homologs of ovuliferous scales. Our results were not congruent with the hypothesis that the tooth of the Cryptomeria seed cone is homologous to the Picea ovuliferous scale. Likewise, the hypothesis that the bracts of Thujopsis and Juniperus contain fused ovuliferous scales was not supported. However, we found expression of AGAMOUS homologs in the sterile bracts of Cupressaceae seed cones at late developmental stages. This expression probably represents a novel gene function in these conifer families, since no corresponding expression has been identified in Pinaceae. Our study suggests that the evolutionary history of modern conifer cones is more diverse than previously thought.

Recurrent abnormalities in conifer cones and the evolutionary origins of flower-like structures.

Conifer cones are reproductive structures that are typically of restricted growth and either exclusively pollen-bearing (male) or exclusively ovule-bearing (female). Here, we review two common spontaneous developmental abnormalities of conifer cones: proliferated cones, in which the apex grows vegetatively, and bisexual cones, which possess both male and female structures. Emerging developmental genetic data, combined with evidence from comparative morphology, ontogeny and palaeobotany, provide new insights into the evolution of both cones and flowers, and prompt novel strategies for understanding seed-plant evolution.

A character-based approach in the Mexican cycads supports diverse multigene combinations for DNA barcoding.

A DNA barcoding study was conducted to determine the optimal combination of loci needed for successful species-level molecular identification in three extant cycad genera-Ceratozamia, Dioon, and Zamia-that occur in Mexico. Based on conclusions of a previous multigene study in representative species of all genera in the Cycadales, we tested the DNA barcoding performance of seven chloroplast coding (matK, rpoB, rpoC1, and rbcL) and non-coding (atpF/H, psbK/I, and trnH-psbA) regions, plus sequences of the nuclear internal transcribed spacer. We analysed data under the assumptions of the "character attributes organization system" (CAOS), a character-based approach in which species are identified through the presence of 'DNA diagnostics'. In Ceratozamia, four chloroplast regions and one nuclear region were needed to achieve > 70% unique species identification. In contrast, the two-gene combination atpF/H + psbK/I and the four-gene combination atpF/H + psbK/I + rpoC1 + ITS2 were needed to reach 79% and 75% unique species identification in Dioon and Zamia, respectively. The combinations atpF/H + psbK/I and atpF/H + psbK/I + rpoC1 + ITS2 include loci previously considered by the international DNA barcoding community. However, none of the three combinations of potential DNA barcoding loci found to be optimal with a character-based approach in the Mexican cycads coincides with the 'core barcode' of chloroplast markers (matK + rbcL) recently proposed for universal use in the plant kingdom.

Character-based, population-level DNA barcoding in Mexican species of Zamia L. (Zamiaceae: Cycadales).

BACKGROUND AND AIMS: With the recent proposal of matK and rbcL as core plant DNA barcoding regions by the Consortium for the Barcoding of Life Plant Working Group, the construction of reference libraries in the botanical DNA barcoding initiative has entered a new phase. However, in a recent DNA barcoding study in the three Mexican genera of the gymnosperm order Cycadales, we found that neither matK nor rbcL allow high levels of molecular identification of previously established species. MATERIALS AND METHODS: Our data analysis in that study rested on the "Characteristic Attributes Organization System" (CAOS), a character-based algorithm for the definition of "DNA diagnostics." Here, we use CAOS to analyze a population-level molecular data set in Zamia, one of the three cycad genera occurring in Mexico, whose populations display contrasting biogeographic patterns. Our population-level study, which includes all species in the region formally known as Megamexico, is restricted to the genome region, which showed the best single-locus molecular identification performance in our previous study-namely, the noncoding intergenic chloroplast spacer psbK-I. RESULTS: Our comparison of single-individual vs. population-level psbK-I datasets in Zamia indicates that CAOS analyses are sensitive to slight alignment changes, which in turn derive from the different amounts of molecular variation present in each matrix type. CONCLUSION: We, therefore, suggest that character-based studies that involve population-level data should contemplate this type of comparison between data matrices, before a set of DNA diagnostics in a given DNA barcoding reference library is considered definitive.

Pattern cladistics and the 'realism-antirealism debate' in the philosophy of biology.

Despite the amount of work that has been produced on the subject over the years, the 'transformation of cladistics' is still a misunderstood episode in the history of comparative biology. Here, I analyze two outstanding, highly contrasting historiographic accounts on the matter, under the perspective of an influential dichotomy in the philosophy of science: the opposition between Scientific Realism and Empiricism. Placing special emphasis on the notion of 'causal grounding' of morphological characters (sensu Olivier Rieppel) in modern developmental biology's (mechanistic) theories, I arrive at the conclusion that a 'new transformation of cladistics' is philosophically plausible. This 'reformed' understanding of 'pattern cladistics' entails retaining the interpretation of cladograms as 'schemes of synapomorphies', but in association to construing cladogram nodes as 'developmental-genetic taxic homologies', instead of 'standard Darwinian ancestors'. The reinterpretation of pattern cladistics presented here additionally proposes to take Bas Van Fraassen's 'constructive empiricism' as a philosophical stance that could properly support such analysis of developmental-genetic data for systematic purposes. The latter suggestion is justified through a reappraisal of previous ideas developed by prominent pattern cladists (mainly, Colin Patterson), which concerned a scientifically efficient 'observable/non-observable distinction' linked to the conceptual pair 'ontogeny and phylogeny'. Finally, I argue that a robust articulation of Antirealist alternatives in systematics may provide a rational basis for its disciplinary separation from evolutionary biology, as well as for a critical reconsideration of the proper role of certain Scientific Realist positions, currently popular in comparative biology.