Discrete Morphological Characters Research Articles

Size, not phylogeny, explains the morphology of the endosseous labyrinth in the crown clade Crocodylia.

The endosseous labyrinths are associated with several functions, including hearing and spatial orientation. Throughout their evolutionary history, crocodylomorphs have thrived in diverse environments, and the morphology of their endosseous labyrinths has been suggested as a proxy for inferring their lifestyle. However, the relationships between the shape of their endosseous labyrinths and ontogenetic and phylogenetic factors are difficult to interpret and have rarely been investigated in depth previously, particularly in terms of dataset size. Here, we present the most complete dataset to date on the endosseous labyrinths of extant crocodylians, including 111 specimens covering 22 species of different ontogenetic status (from hatchlings to adults). Using 3D geometric morphometrics, we show that allometry constitutes a major contributor of the shape variation of the crocodylian endosseous labyrinths and that the development of this structure is likely linked to the braincase conformation, in all extant genera. We also find a moderate phylogenetic signal, but only without considering the size effect, so it could not be translated into relevant discrete morphological characters. Based on these results, we discuss several remaining problems that prevent the inclusion of fossil forms with highly divergent lifestyles to study how ecological differences shaped the endosseous labyrinths of crocodylomorphs.

Functional and Character Disparity Are Decoupled in Turtle Mandibles.

Turtles have high shape variation of their mandibles, likely reflecting adaptations to a broad variety of food items and ingestion strategies. Here, we compare functional disparity measured by biomechanical proxies and character disparity measured by discrete morphological characters. Functional and character disparities vary between clades and ecological groups and are thus decoupled. Comparisons with cranial disparity also indicate decoupled patterns within the turtle skull. Exploration of mandibular patterns reveals that several biomechanical configurations or character state combinations can lead to the same feeding type (i.e., convergence) or that high functional disparity can be achieved at a low exhaustion of character state combinations (e.g., cryptodires). Dietary specialists show larger functional disparity than generalists, but the phylogenetically widespread generalist ecology leads to high character disparity signals in the ecotype. Whereas character disparity generally shows high phylogenetic signal, functional disparity patterns correspond to dietary specializations, which may occur convergently across different groups. Despite this, individual functional measurements have overlapping ranges across ecogroups and do not always conform to biomechanical expectations. Jaw opening and closing biomechanical advantages model trade-offs between force transmission and opening/closing speeds, and turtles show a variety of combinations of values that we try to synthesize into several "jaw types". Closing mechanical advantage shows that turtles retain high levels of force transmission at the anterior jaw end compared with other groups (e.g., pseudosuchians). This can possibly be explained as an evolutionary adaptation to retain high bite forces at small head sizes.

A new Boulenophrys species (Anura, Megophryidae) from the coastal hills of eastern Fujian Province, China.

A new species of the genus Boulenophrys is described from the coastal hills of eastern Fujian Province, China. The new taxon can be distinguished from all recognized congeners by a combination of discrete morphological character state differences and genetic divergences in the combined mitochondrial 16S + CO1 genes. We also provide a map showing the distribution pattern of Boulenophrys species in Fujian and a provincial-specific key, which will aid their conservation by helping the local authorities accurately identify species during field identifications and data collection efforts.

Parallel evolution of unusual ‘harpiform’ morphologies in distantly related trilobites

Abstract Harpetid and trinucleid trilobites share a similar and unusual morphology, the most striking feature of which is a wide, flattened cephalic brim with many pits or holes. This similarity was once interpreted as a sign that these two groups of trilobites were closely related, but in recent years it has instead been assumed that the ‘harpiform’ brim arose in both groups independently. However, relatedness and similarity can be difficult to disentangle in fossil taxa without close living relatives, and this assumption about the harpiform brim has never been explicitly tested. Our study re-evaluates the relationship between Harpetida and Trinucleioidea in order to test a longstanding assumption about trilobite relationships and as a case study in evaluating different kinds of morphological similarity in extinct groups. We inferred a new phylogenetic tree using parsimony methods and discrete morphological character data from a broad sampling of harpetids, trinucleids, and their relatives. Despite their gross morphological similarities, we found that harpetids and trinucleids were readily distinguished in our analyses, a result consistent with a hypothesis of multiple origins for the harpiform brim. By mapping brim-related characters across our new phylogeny, we identified a sequence of morphological innovations that arose in parallel in both groups and led ultimately in each case to the evolution of the harpiform brim. These results indicate that harpiform brims are a prime example of parallel evolution—the similar development of a morphological trait in distantly related taxa that nevertheless share a similar original morphology. In addition, our phylogeny supports the idea that trinucleids are specialized, harpiform asaphids, rather than an independent order of trilobites. We also provide new information on the relationships of the putative ‘basal-most’ members of Trinucleioidea, the Liostracinidae, and confirm recent assessments that this family is more distantly related to trinucleids.

Is the Current Systematic Subdivision of the Subfamily Neanurinae (Collembola, Neanuridae) Still Valid? Testing the Monophyly and Phylogenetic Relationships of Currently Established Tribes of the Neanurinae.

The subfamily Neanurinae is the largest in the family, with almost 800 described species. These springtails differ significantly from all other Collembola in their morphology, behaviour, and natural habitats. A systematic division of the Neanurinae into tribes was proposed more than 30 years ago by Cassagnau (1989), but it has not yet been tested using cladistic methods. Recent studies, both phylogenetic analyses of individual tribes or genera and descriptions of new taxa, suggest that the currently recognised tribes may not be monophyletic. The phylogenetic relationships among major lineages of the Neanurinae were explored by analysing a dataset of 101 discrete morphological characters. Bayesian and maximum parsimony analyses yielded similar tree topologies. The relationships among the Neanurinae were not resolved in any of the analyses, except for the support for the monophyly of the tribe Lobellini. The results indicate that the taxonomic characters used in the classification of Neanurinae are shared among members of the different tribes, which may have resulted in a classification with little phylogenetic basis. The article discusses the phylogenetic significance of morphological characters, including those recognised as key to the evolution and history of Neanurinae.

A new Paleogene fossil and a new dataset for waterfowl (Aves: Anseriformes) clarify phylogeny, ecological evolution, and avian evolution at the K-Pg Boundary.

Despite making up one of the most ecologically diverse groups of living birds, comprising soaring, diving and giant flightless taxa, the evolutionary relationships and ecological evolution of Anseriformes (waterfowl) remain unresolved. Although Anseriformes have a comparatively rich, global Cretaceous and Paleogene fossil record, morphological datasets for this group that include extinct taxa report conflicting relationships for all known extinct taxa. Correct placement of extinct taxa is necessary to understand whether ancestral anseriform feeding ecology was more terrestrial or one of a set of diverse aquatic ecologies and to better understand avian evolution around the K-T boundary. Here, we present a new morphological dataset for Anseriformes that includes more extant and extinct taxa than any previous anseriform-focused dataset and describe a new anseriform species from the early Eocene Green River Formation of North America. The new taxon has a mediolaterally narrow bill which is rarely found in previously described anseriform fossils. The matrix created to assess the placement of this taxon comprises 41 taxa and 719 discrete morphological characters describing skeletal morphology, musculature, syringeal morphology, ecology, and behavior. We additionally combine the morphological dataset with published sequences using Bayesian methods and perform ancestral state reconstruction for select morphological, ecological and behavioral characters. We recover the new Eocene taxon as the sister taxon to (Anseranatidae+Anatidae) across all analyses, and find that the new taxon represents a novel ecology within known Anseriformes and the Green River taxa. Results provide insight into avian evolution during and following the K-Pg mass extinction and indicate that Anseriformes were likely ancestrally aquatic herbivores with rhamphothecal lamellae..

Exploring Phylogenetic Relationships of the Mecocephala Group (Hemiptera: Pentatomidae) Using Continuous and Discrete Characters, with Notes on Taxonomy.

The Mecocephala group comprises about 50 species, restricted to the Neotropics and with the highest species richness in Neotropical South America. Several species use rice as host plants and their identification is facilitated by the presence of exaggerated head proportions and a unique male genitalic morphology. The taxonomy of the group has been extensively explored, but inferring its monophyly and especially its internal phylogenetic relationships has been challenging. Here, we inferred the phylogenetic relationships for the group assembling the most complete taxonomic sampling to date, analyzing discrete and continuous morphological characters through equal and implied weighted parsimony analyses. The monophyly of the group was recovered, but internal relationships varied slightly according to the dataset tested. Thus, we propose internal arrangements for the group and provide a formal description of the Mecocephala group, diagnoses for each genus, a dichotomous key to identify its genera, and illustrations of the morphological characters and type species.

Mind the gap: new records of Caenolestes in the Western Andes of Colombia challenge its current biogeographic patterns

Abstract The genus Caenolestes is the most species-rich of the marsupial order Paucituberculata. Two species inhabit Colombia (and also occur in Ecuador) with a discontinuous distribution that has not been accounted for in previous studies—Caenolestes fuliginosus known from the Central and Eastern Andes, and C. convelatus restricted to the Western Andes. Here, we present new and noteworthy records of Caenolestes from the Western Andes at the distributional gap of C. convelatus, and outside the known range of C. fuliginosus. We present detailed comparisons using discrete and continuous diagnostic morphological characters, with type material and additional specimens collected nearby, to assess the identity of the new specimens. We performed statistical analyses at species and subspecies levels, and used a principal components analysis to explore the ordination of the new specimens in morphological space. We found that although these specimens are from the Western Andes, they present traits similar to C. fuliginosus and show great overlap with the morphospace of that species. The new records did not differ statistically with C. fuliginosus or any of its subspecies, but they differed in 20 craniodental measurements from C. convelatus. We also report differences at subspecies level within and between species. Based on these observations, we identified these records as C. fuliginosus, expanding its known distribution to the midportion of the Western Andes, across de Cauca valley. We discuss the biogeography of these 2 species in light of the new data and the context of high Andean habitats, especially regarding the contrasting biogeographical patterns found in other taxa in the Northern Andes. Finally, we discuss the need for a new and exhaustive review of the systematics and biogeography of the genus.

Phylogeny and historical biogeography of the leafhopper subfamily Coelidiinae (Hemiptera: Cicadellidae) based on morphological and molecular data

AbstractThe phylogenetic relationships among major lineages of the globally distributed leafhopper subfamily Coelidiinae were reconstructed by analysis of 2903 nucleotide positions from two mitochondrial genes (COI and 16S), four nuclear genes (28S, H3, H2A and Wingless) and 102 discrete morphological characters, compiled for 86 species representing 52 genera within 9 coelidiine tribes broadly representative of the world fauna in addition to 12 outgroup taxa. Maximum likelihood and Bayesian analyses yielded well‐resolved phylogenetic estimates that were highly congruent with most branches receiving strong support. The results indicate Coelidiinae sensu stricto (=Coelidiinae sensu lato without Equeefini and Macroceratogoniini), Thagriini, Tharrini, Tinobregmini and Equeefini are monophyletic. However, the two largest tribes, Coelidiini and Teruliini, are paraphyletic, as well as Youngolidiini and most genera of Oriental Coelidiini. Fossil‐calibrated molecular divergence time analysis indicates that the Coelidiinae sensu stricto originated ca. 149 Ma, prior to the complete separation of the Gondwanan continents, and the tribe‐level lineages diverged between the Lower and Upper Cretaceous (92.77–138.03 Ma). The major lineages of Coelidiinae arose in the Oriental and Neotropical regions, and Oriental Coelidiini arose as a result of dispersal and colonisation from the Afrotropical region.

Performance of tree-building methods using a morphological dataset and a well-supported Hexapoda phylogeny.

Recently, many studies have addressed the performance of phylogenetic tree-building methods (maximum parsimony, maximum likelihood, and Bayesian inference), focusing primarily on simulated data. However, for discrete morphological data, there is no consensus yet on which methods recover the phylogeny with better performance. To address this lack of consensus, we investigate the performance of different methods using an empirical dataset for hexapods as a model. As an empirical test of performance, we applied normalized indices to effectively measure accuracy (normalized Robinson-Foulds metric, nRF) and precision, which are measured via resolution, one minus Colless' consensus fork index (1-CFI). Additionally, to further explore phylogenetic accuracy and support measures, we calculated other statistics, such as the true positive rate (statistical power) and the false positive rate (type I error), and constructed receiver operating characteristic plots to visualize the relationship between these statistics. We applied the normalized indices to the reconstructed trees from the reanalyses of an empirical discrete morphological dataset from extant Hexapoda using a well-supported phylogenomic tree as a reference. Maximum likelihood and Bayesian inference applying the k-state Markov (Mk) model (without or with a discrete gamma distribution) performed better, showing higher precision (resolution). Additionally, our results suggest that most available tree topology tests are reliable estimators of the performance measures applied in this study. Thus, we suggest that likelihood-based methods and tree topology tests should be used more often in phylogenetic tree studies based on discrete morphological characters. Our study provides a fair indication that morphological datasets have robust phylogenetic signal.

Fast Bayesian Inference of Phylogenies from Multiple Continuous Characters.

Time-scaled phylogenetic trees are an ultimate goal of evolutionary biology and a necessary ingredient in comparative studies. The accumulation of genomic data has resolved the tree of life to a great extent, yet timing evolutionary events remain challenging if not impossible without external information such as fossil ages and morphological characters. Methods for incorporating morphology in tree estimation have lagged behind their molecular counterparts, especially in the case of continuous characters. Despite recent advances, such tools are still direly needed as we approach the limits of what molecules can teach us. Here, we implement a suite of state-of-the-art methods for leveraging continuous morphology in phylogenetics, and by conducting extensive simulation studies we thoroughly validate and explore our methods' properties. While retaining model generality and scalability, we make it possible to estimate absolute and relative divergence times from multiple continuous characters while accounting for uncertainty. We compile and analyze one of the most data-type diverse data sets to date, comprised of contemporaneous and ancient molecular sequences, and discrete and continuous morphological characters from living and extinct Carnivora taxa. We conclude by synthesizing lessons about our method's behavior, and suggest future research venues.

Variation of sperm size and evolution of giant spermatozoa in Lonchopteridae (Diptera)

Among species of the spear-winged flies (Lonchopteridae) there is remarkable variation in sperm size, with some species producing giant spermatozoa. With a length of 7500 μm and a width of 1.3 μm the spermatozoon of Lonchoptera fallax ranks among the largest known to date. In the present study body size, testis size, sperm size, and spermatid number per bundle and per testis were examined across 11 Lonchoptera species. Results are discussed in terms of how these characters are related with each other and how their evolution affects the resource allocation amongst spermatozoa. Based on some discrete morphological characters and a molecular tree derived from DNA barcodes a phylogenetic hypothesis of the genus Lonchoptera is proposed. The occurrence of giant spermatozoa in Lonchopteridae is compared to convergent occurrences reported in other taxa.

Multivariate mapping of ontogeny, taphonomy and phylogeny to reconstruct problematic fossil taxa.

Exceptionally preserved fossils of soft-bodied organisms provide unique evidence of evolutionary history, but they are often contentious; different approaches frequently produce radically different reconstructions of taxa and their affinities. Conflict arises due to difficulties in disentangling the three non-independent factors that underlie all morphological variation within and between fossils: ontogeny, taphonomy and phylogeny. Comparative data from extant organisms can be extremely powerful in this context, but is often difficult to apply given the multi-dimensionality of anatomical variation. Here, we present a multivariate ordination method using discrete morphological character data from modern taxa at different ontogenetic and taphonomic stages (semaphoront and 'semataphonts'). Analysing multiple axes of morphological variation simultaneously allows us to visualize character combinations that are likely to exist in fossil specimens at intersecting stages of growth and decay, and thus constrain interpretation of fossils. Application to early vertebrates finds variation in fossil specimens to be accounted for by all three axes: primarily decay in Mayomyzon, ontogeny in Priscomyzon and phylogeny in 'euphaneropoids' and Palaeospondylus. Our demonstration of empirical multi-factorial variation underscores the power of multivariate approaches to fossil interpretation, especially non-biomineralized taxa. As such, this conceptual approach provides a new method for resolving enigmatic taxa throughout the fossil record.

Molluscs of the family Bithyniidae (Mollusca, Gastropoda) of Tyumen Region

The work is based on a study of long-term collections of molluscs of the family Bithyniidae from the waterbodies of the Tyumen region (Western Siberia), located within the world’s largest Ob-Irtysh natural focus of opisthorchiasis. Difficulties with species identifications of bithyniid snails, the first intermediate hosts of Opisthorchis , necessitate the publication of photographic images of Bithyniidae shells and an identification key based on discrete morphological characters. It has been established that 14 species of Bithyniidae belonging to five genera inhabit the Tyumen region, an annotated list of species is given, and a brief zoogeographical description is given. The most abundant species are Digyrcidum starobogatovi and Boreoelona sibirica, whereas Paraelona milachevitchi were found solitary.

Phylogenetic Analysis of the Genus Planaphrodes Hamilton (Hemiptera, Cicadellidae, Aphrodinae) Based on Morphological Characteristics, with Revision of Species from China, Korea and Japan

A morphology-based phylogeny of the Holarctic leafhopper genus Planaphrodes Hamilton is reconstructed for the first time based on 39 discrete male adult morphological characters. The results support the monophyly of Planaphrodes, with the included species forming two monophyletic lineages defined mainly by the number and location of aedeagus processes. The position of Planaphrodes in the Aphrodini was resolved as follows: (Stroggylocephalus + (Anoscopus + (Planaphrodes + Aphrodes))). The fauna of Planaphrodes from China, Japan and Korea are reviewed and six species are recognized, including two new species: P. bifasciatus (Linnaeus), P. sahlbergii (Signoret), P. nigricans (Matsumura), P. laevus (Rey), P. baoxingensis sp. nov. (China: Sichuan) and P. faciems sp. nov. (China: Hubei). Acocephalus alboguttatus Kato, 1933 syn. nov. and Aphrodes daiwenicus Kuoh, 1981 syn. nov. are considered junior synonyms of Planaphrodes sahlbergii (Signoret, 1879). Planaphrodes bella Choe, 1981 is a junior synonym of Planaphrodes nigricans (Matsumura, 1912). A checklist and key to species of Planaphrodes are provided.

A new kannemeyeriiform dicynodont (Synapsida) from a Late Triassic vertebrate assemblage in west Texas, U.S.A.

ABSTRACT A new kannemeyeriiform dicynodont is described from the Upper Triassic Tecovas Formation (Dockum Group) of west Texas, U.S.A. The taxon, Argodicynodon boreni gen. et sp. nov., is diagnosed by numerous cranial characters including: squamosal-interparietal sutural contact broad and interdigitating; tall, narrow intertemporal region formed by the parietals with long postorbitals forming the lateral face of the dorsal platform; interparietal forms knobby, bilobed exostoses that wedge between the parietals to form a W-shaped outline in dorsal view; basioccipital and exoccipital contributions to the occipital condyle are distinct, and the dorsal fossa separating the exoccipitals is deeply incised and dorsoventrally deep; caniniform process of the maxilla is dorsoventrally deep and well developed; and an elongated tab-like medial process of the articular exceeds the width of the quadrate roller. A phylogenetic analysis based on 23 continuous and 176 discrete (numeric) morphological characters and 120 taxa finds Argodicynodon conservatively to be a placeriine near the Placerias + Moghreberia group, representing the oldest placeriine in the southwestern U.S.A. and the first named dicynodont genus from the Dockum Group of Texas. A review of Euramerican dicynodont records exposes their hidden diversity and abundance in Laurasia during the Late Triassic. The records of Argodicynodon and other previously undescribed dicynodont fossils from nearby localities underscores the diversity of non-Placerias dicynodonts in the North American Upper Triassic. http://zoobank.org/urn:lsid:zoobank.org:pub:AB9B7ABC-6C84-4B04-909F-F1DA114030AB

A new species of jupati, genusMetachirusBurmeister 1854 (Didelphimorphia, Didelphidae) for the Brazilian Amazon

AbstractThe brown or pouchless four-eyed opossums or jupatis represent the genusMetachiruswith a wide geographical range in the Neotropics. Recent studies show distinct monophyletic clades with high genetic divergence and recognized two species,Metachirus nudicaudatusandMetachirus myosuros. Nevertheless, there is a need for systematic revision with multiple sources of evidence on the taxonomy ofMetachirus, which has never been fully revised. Here we describe a new species ofMetachirusfor the Brazilian Amazon from the Xingu/Tocantins interfluve using the unification of concepts and evolutionary significant units, morphological, genetic, and geographic data. Our analysis reveals a new species withinMetachirusas a differentiated Amazonian clade from the Serra dos Carajás region and the Caxiuanã National Forest, both in the Xingu endemism centre. This new species can be distinguished from the type species,M. nudicaudatusand fromM. myosurosthrough discrete external morphological characters, including cranium and dentition, and molecular data with an average degree of divergence, but ancient divergence time for the mitochondrial cytochromebgene. The Amazon River delimits the distribution of the new species, which also occurs in areas under strong anthropogenic pressure, reinforcing the importance to guide conservation strategies for the region.

Phylogenetic revision of Dennstaedtioideae (Dennstaedtiaceae: Polypodiales) with description of Mucura, gen. nov.

AbstractWe undertook a molecular phylogenetic revision of hayscented ferns (Dennstaedtiaceae: Dennstaedtioideae) using four plastid markers. Our sampling represents ca. 40% of the extant diversity and includes the type species for each of the relevant segregate genera. We coded 18 discrete morphological characters which we used to find diagnosable clades. We show that Dennstaedtia is polyphyletic, with the majority of species forming three morphologically distinct clades, but its type (D. flaccida) is nested within Microlepia. As such, we support the conservation of Dennstaedtia with a new type, D. dissecta. Following our results, we develop a classification of four genera: Dennstaedtia, Microlepia, Mucura (gen. nov.) and Sitobolium. Beyond the inclusion of D. flaccida, we propose to maintain Microlepia with its current circumscription. Except for a single adventive species in the Neotropics, Microlepia is a Paleotropical genus of about 60 species diagnosed by their distinctive perispore ornamentation of rodlets, and by petioles that lack epipetiolar buds. Mucura is a Neotropical genus of two species that differ from all other Dennstaedtiaceae by the combination of dichotomously branching rhizomes, petioles that lack epipetiolar buds, marginal sori with both abaxial and adaxial indusia, and trilete spores with a unique perispore ornamentation. As defined here, Dennstaedtia is a pantropical genus of about 55 species recognized by having unbranched rhizomes, petioles bearing epipetiolar buds, and by often bearing proliferous buds upon the leaves. Sitobolium is a small clade of ca. five species distinguished by their relatively small leaves that have elongate catenate hairs. These hairs often bear a capitate non‐glandular terminal cell. In support of our classification, we provide a key to the eleven genera of Dennstaedtiaceae, and for the four genera of Dennstaedtioideae we provide morphological and geographic synopses, a list of constituent species, and necessary new combinations.

A long-flowering Hechtia (Bromeliaceae): Hechtia sanchezii, a new species from San Luis Potosí, Mexico

Background: Hechtia is known among Bromeliaceae by its unisexual, sexually dimorphic, mainly fragrant flowers and dioecy; delimitation of taxa particularly on those with lateral inflorescence, requires qualitative morphological evidence from both sexes, because dimensions of structures change during its growth.
 Hypotheses: Hechtia species are delimitated based on a combination of discrete morphological characters from both sexes, associated with narrow geographical distributions. If examination of populations of San Luis Potosí shows characters that place the taxon in the genus and distinguish it from other species in Hechtia, the taxon will be described as new.
 Taxon: Hechtioideae, Hechtia sp. nov.
 Study site and dates: Mexican State of San Luis Potosí and vicinities, 2015-2021.
 Methods: Live plants as well as herbarium material of the new taxon and the most morphological similar species, were analyzed, with examination of inflorescences and flowers of both sexes, fruits, and seeds. Geographical distribution was mapped and conservation status using IUCN criteria is reported for the new species.
 Results: Hechtia sanchezii has been confused with H. glomerata since both share lateral, glomerulate-like infructescences, but H. sanchezii shows red to ferruginous indumenta on floral bracts and sepals (vs. white), these red (vs. greenish or brownish), pink petals (vs. white), scentless (vs. fragrant) flowers, stamens with filaments of two lengths, three epipetalous, and three alternating with petals (vs. two lengths but all filaments epipetalous).
 Conclusions: Morphological and geographical evidence allow the recognition of H. sanchezii as a new species native from San Luis Potosí, Mexico.

Morphology-based Phylogenetic Analysis of Membracoidea (Hemiptera: Cicadomorpha) With Placement of Fossil Taxa and Description of a New Subfamily

Abstract Recently discovered amber-preserved fossil Cicadellidae exhibit combinations of morphological traits not observed in the modern fauna and have the potential to shed new light on the evolution of this highly diverse family. To place the fossils explicitly within a phylogenetic context, representatives of five extinct genera from Cretaceous Myanmar amber, and one from Eocene Baltic amber were incorporated into a matrix comprising 229 discrete morphological characters and representatives of all modern subfamilies. Phylogenetic analyses yielded well resolved and largely congruent estimates that support the monophyly of most previously recognized cicadellid subfamilies and indicate that the treehoppers are derived from a lineage of Cicadellidae. Instability in the morphology-based phylogenies is mainly confined to deep internal splits that received low branch support in one or more analyses and also were not consistently resolved by recent phylogenomic analyses. Placement of fossil taxa is mostly stable across analyses. Three new Cretaceous leafhopper genera, Burmotettix gen. nov., Kachinella gen nov., and Viraktamathus gen. nov., consistently form a monophyletic group distinct from extant leafhopper subfamilies and are placed in Burmotettiginae subfam. nov. Extinct Cretaceous fossils previously placed in Ledrinae and Signoretiinae are recovered as sister to modern representatives of these groups. Eomegophthalmus Dietrich and Gonçalves from Baltic amber consistently groups with a lineage comprising treehoppers, Megophthalminae, Ulopinae, and Eurymelinae but its position is unstable. Overall, the morphology-based phylogenetic estimates agree with recent phylogenies based on molecular data alone suggesting that morphological traits recently used to diagnose subfamilies are generally informative of phylogenetic relationships within this group.