The field of Evolutionary Developmental biology arose with the promise of new approaches to answering longstanding questions of comparative biology. Here we review the fruits of that promise some decades later. We chose three areas of arthropod EvoDevo—evolution of body plans, segment number, and appendage morphology—to provide an overview for the nonspecialist of how these issues have been clarified by the comparative analysis of regulatory gene networks. In all cases, we identify substantial progress and novel insights provided by the tools and perspective of EvoDevo. We also recognize that some core questions remain unanswered, and we reflect on how discoveries in EvoDevo fit in the landscape of other progress in phylogenetics, population biology, and genomics, facilitated by a new and ever-expanding set of molecular tools for comparative studies in evolution.

Mimulus guttatus DC. (yellow monkey-flower; Phrymaceae) is an important model species for ecological and evolutionary studies, being locally adapted to a wide range of elevation, moisture and temperature gradients, soil types, and pollinator availabilities. In order to advance this species as a model for evolutionary genetic studies, we have developed virus-induced gene silencing (VIGS) using the tobacco rattle virus (TRV) to assay gene function. We demonstrate the effectiveness of Agrobacterium-mediated VIGS in two divergent populations of M. guttatus, Iron Mountain 767 (IM767) and Point Reyes (PR). Plants infected with a fragment of the carotenoid biosynthesis pathway gene PHYTOENE DESATURASE (PDS) cloned into the TRV2 vector exhibited endogenous PDS silencing and photobleached phenotypes. We further assayed for VIGS-induced floral phenotypes by silencing paralogous genes putatively affecting floral symmetry, CYCLOIDEA1 (CYC1) and CYCLOIDEA2 (CYC2). Simultaneous silencing of CYC1 and CYC2 resulted in organ number defects in the petal and stamen whorls; silencing of CYC1 affected petal margin growth; and silencing of CYC2 had no effect on flower development. Infection with TRV2 and TRV1 is significantly higher and more pervasive in the IM767 versus the PR population and is more efficient after vacuum infiltration. These results demonstrate the efficacy of VIGS for determining the function of developmental genes, including those involved in ecologically important reproductive traits.

The MADS-box genes form a large family of pan-eukaryotic transcription factors that are involved in various aspects of plant growth and development, particularly reproduction. To understand the extent of their conservation and divergence in the emerging model genus Aquilegia L. (Ranunculaceae), we have annotated 47 MADS-box containing loci from the recently released hybrid A. coerulea E. James ‘Origami' genome sequence. Phylogenetic analysis of these sequences along with those previously identified from Arabidopsis (DC.) Heynh. and Oryza L. demonstrates that we were able to recover members of all major subfamilies with the exception of clear Mβ representatives. The evolution of the Aquilegia type I loci is similar to what has been observed for other angiosperms in exhibiting relatively recent gene radiation events. In contrast, the type II loci are distributed across 12 subfamilies that were established before the diversification of the angiosperms. Overall, expressed sequence tag (EST) data exist for 20 of these loci; further characterization of gene expression patterns will be an important next step. This characterization of Aquilegia MADS-box transcription factors thereby lays the foundation for many crucial studies on the development and evolution of Aquilegia as well as the conservation of function across the MADS-box gene family.

The tribe Bignonieae includes all Neotropical lianescent Bignoniaceae. The leaves of Bignonieae are generally 2- or 3-foliolate, with terminal leaflets modified into a tendril. These tendrils have varied morphologies and are thought to have been involved in the diversification of Bignonieae. Little, however, is still known about the biology and evolution of tendrils. This study investigated the evolution and development of tendril types in Bignonieae in order to further understand how changes in leaf morphogenesis led to current patterns of variation in tendril morphology. For that, we investigated the ontogeny of 11 species representing a wide diversity of tendril types (i.e., simple, trifid, and multifid) and used a recently published phylogeny of Bignonieae as the basis to reconstruct patterns of evolution for tendril types. For those analyses, we used maximum likelihood (ML) and maximum parsimony (MP) approaches, with both ACCTRAN and DELTRAN optimization schemes implemented in the latter. Ancestral character state reconstructions of tendril type suggest that the ancestral condition for the whole tribe (Core Bignonieae plus Perianthomega Bureau ex Baill.) is a lack of tendrils, whereas parsimony reconstructions indicate an ambiguous ancestral condition. However, all reconstructions suggest that trifid tendrils represent the ancestral condition for the Core Bignonieae. Other tendril types evolved subsequently through a series of developmental changes. Furthermore, tendril ontogenetic studies provided key information for the resolution of major ambiguities in the ancestral state reconstructions of tendril type in Bignonieae. For instance, in Bignonia callistegioides Cham. and B. prieurei DC. (simple tendrils), no traces of remnant lateral branches from a trifid-tendrilled ancestor were found, corroborating the ACCTRAN hypothesis of a simple tendril condition for the ancestor of that lineage. In Tanaecium pyramidatum (Rich.) L. G. Lohmann (trifid tendrils), on the other hand, we detected a pattern and rate of tendril differentiation that initially followed the same pattern seen in taxa with simple tendrils (i.e., Cuspidaria DC. and Fridericia Mart.), with a developmental delay relative to other trifid-tendrilled species, favoring a simple-tendrilled ancestor hypothesis and supporting the ML and ACCTRAN optimizations. The interpretation of the ontogenetic data in light of a robust phylogenetic framework led to specific hypotheses about the evolutionary processes and respective changes in gene regulation that may have led to the current tendril morphologies found in Bignonieae. In particular, we suggest that tendril evolution involved heterochrony and hypothesize that changes in the expression of genes that are associated with compound leaf development may have led to the diversity of tendril morphology currently observed in Bignonieae.

The history of classification of the tribe Bignonieae and its genera are reviewed as context for a comprehensive new genus-level classification of the tribe Bignonieae (Bignoniaceae, Lamiales). This new classification is based on a well-supported phylogeny based on multiple molecular markers from both chloroplast and nuclear DNA, a morphological survey, and a broad sampling of taxa. Genera are circumscribed here as clades that are well supported as monophyletic by molecular data and also recognizable by one or more morphological synapomorphies. Perianthomega Bureau ex Baill. is here transferred from Bignoniaceae tribe Tecomeae into Bignonieae, and 21 genera and a total of 393 species are recognized in Bignonieae: Adenocalymma Mart. ex Meisn. (82 species), Amphilophium Kunth (47), Anemopaegma Mart. ex Meisn. (45), Bignonia L. (28), Callichlamys Miq. (1), Cuspidaria DC. (19), Dolichandra Cham. (8), Fridericia Mart. (67), Lundia DC. (13), Manaosella J. C. Gomes (1), Mansoa DC. (12), Martinella Baill. (2), Neojobertia Baill. (2), Pachyptera DC. ex Meisn. (4), Perianthomega (1), Pleonotoma Miers (17), Pyrostegia C. Presl (2), Stizophyllum Miers (3), Tanaecium Sw. (17), Tynanthus Miers (15), and Xylophragma Sprague (7). Several genera are here circumscribed differently from previous classifications, in particular Memora Miers and Sampaiella J. C. Gomes are synonymized with Adenocalymma; Distictella Kuntze, Distictis Mart. ex Meisn., Glaziova Bureau, Pithecoctenium Mart. ex DC., and Urbanolophium Melch. are synonymized with Amphilophium; Cydista Miers, Clytostoma Miers ex Bureau, Macranthisiphon Bureau ex K. Schum., Mussatia Bureau ex Baill., Phryganocydia Mart. ex Bureau, Potamoganos Sandwith, Roentgenia Urb., and Saritaea Dugand are synonymized with Bignonia; Macfadyena A. DC., Melloa Bureau, and Parabignonia Bureau ex K. Schum. are synonymized with Dolichandra; Arrabidaea DC. is synonymized with Fridericia; Gardnerodoxa Sandwith is synonymized with Neojobertia; Leucocalantha Barb. Rodr. is synonymized with Pachyptera; and Ceratophytum Pittier, Periarrabidaea A. Samp., Paragonia Bureau, Pseudocatalpa A. H. Gentry, and Spathicalyx J. C. Gomes are synonymized with Tanaecium. The genera Adenocalymma, Amphilophium, Fridericia, Dolichandra, and Tanaecium are formally emended here as to diagnosis and circumscription. A natural key, complete morphological descriptions, and illustrations characterize the accepted genera, and full generic synonymy and a catalogue of their component species summarize their basic nomenclature and geographic range. Three new names are published: B. neouliginosa L. G. Lohmann replaces Phryganocydia uliginosa Dugand; B. neoheterophylla L. G. Lohmann replaces Cydista heterophylla Seibert; and Tanaecium neobrasiliense L. G. Lohmann replaces Sanhilaria brasiliensis Baill. Thirty-two generic names are newly synonymized, and 144 new nomenclatural combinations are made. A lectotype is designated for one genus, Periarrabidaea A. Samp., and 78 species names. One species name is neotypified, Memora campicola Pilg. (≡ Adenocalymma campicola (Pilg.) L. G. Lohmann).

Taxonomic revision of Gouania Jacq. (Rhamnaceae) is presented for the full extent of its range in North America, from Florida and Mexico through Central America to and including Panama, and the islands of the Caribbean region, including the Bahamas. Fifteen species are recognized, five of which are described and published as new: G. croatii A. Pool (Panama and Colombia), G. ferruginea A. Pool (Guatemala and Honduras), G. guiengolensis A. Pool (Oaxaca, Mexico), G. obamana A. Pool (Mexico, Guatemala, Belize, and Honduras), and G. pubidisca A. Pool (Mexico, Guatemala, El Salvador, and Nicaragua). Lectotypes are designated for Banisteria lupuloides L. [≡ G. lupuloides (L.) Urb.] (and the synonymous G. domingensis L.), G. colombiana Suess., G. glabriuscula Stokes, G. lupuloides var. aptera Urb., G. mexicana Sessé & Moc., G. mexicana Rose [≡ G. rosei Wiggins], G. paniculata Spreng., G. pubescens Poir. var. martinicensis Poir., G. pubescens var. pubescens, G. virgata Reissek var. virgata [≡ G. virgata var. guianensis Reissek], G. virgata var. brasiliensis Reissek, and Rhamnus polygama Jacq. [≡ G. polygama (Jacq.) Urb.] (and the synonymous G. tomentosa Jacq.). Epitypes are designated for B. lupuloides L. [≡ G. lupuloides] (and the synonymous G. domingensis L.), G. stipularis DC., and R. polygama Jacq. [≡ G. polygama] (and the synonymous G. tomentosa). A neotype is selected for R. domingensis Jacq. and a lectotype is designated for the equivalent name G. glabra Jacq.