Polarity Of Character States Research Articles

Basal Anseriformes from the Early Paleogene of North America and Europe

We describe nearly complete skeletons of basal Anseriformes from the Latest Paleocene to the early Eocene of North America and Europe. Collectively, these birds appear to be representative of anseriforms near the divergence of Anhimae and Anseres, but their exact positions relative to these clades remains uncertain. A new family, Anachronornithidae nov. fam., is erected on the basis of one of these, Anachronornis anhimops nov. gen., nov. gen. et sp., to which the others cannot be confidently assigned. The new fossils augment a growing collection of early Pan-Anseriformes, which in their diversity do not paint an unambiguous picture of phylogeny or character state evolution on the path to or within crown-Anseriformes. Anachronornis nov. gen. is similar in some aspects of both cranial and postcranial anatomy to other well-represented early Paleogene Anseriformes and members of Anseres, such as Presbyornis Wetmore, 1926. However, it exhibits a more landfowl-like bill, like that of Anhimae and unlike the spatulate bill of Anseres. Additional specimens of similar basal Anseriformes of uncertain affinities from the early Eocene of North America and Europe further complicate interpretation of character state polarity due to the mosaicism of primitive and derived characters they exhibit.

Macroevolution of genome size in sarcopterygians during the water–land transition

Genome size spans over a 300-fold range among vertebrates (132pg for Protopterus aethiopicus, the marbled lungfish, and 0.35pg for Tetraodon nigroviridis, the green spotted pufferfish). While phylogenetic analysis of genome size has helped clarify how this variation evolved in multiple tetrapod groups, the ancestral tetrapod condition still remains poorly characterized, and this obscures our understanding of character state polarity and macroevolutionary trends in genome size. To address this problem, we used phylogenetic comparative methods to analyze paleohistological data from eight taxa of the Middle and Late Paleozoic to the Early Mesozoic: Eusthenopteron, Ichthyostega, Acheloma, Eryops, Trimerorhachis, Wetlugasaurus, an unidentified dissorophoid, and Chroniosaurus. Five other extinct taxa were included from previous studies to better frame our results, including Marmorerpeton, Cardiocephalus, Diplocaulus, an unidentified basal sauropsid, and Mycterosaurus. We augmented a previously reported histological and genome size data set (including data from 14 lissamphibians, three testudines, Sphenodon, five squamates, two crocodilians, 11 birds, and 22 mammals) with genome size and histological data from extant Latimeria and three extant actinopterygians. Our results suggest that all eight of the newly analyzed extinct taxa had genome sizes ranging between 3.2 and 3.9pg. These results imply that basal tetrapods had genome sizes (and underlying genomic architectures) similar to extant mammals and lepidosaurs. We find no major shifts in genome size during the tetrapod water-to-land transition. Our analysis suggests that Eusthenopteron and Ichthyostega had genome sizes well within the range of extant actinopterygians and Latimeria, despite several whole-genome duplications in actinopterygians.

Late stages of anther development and anther attributes in Microepidendrum differs from other genera of Epidendrum alliance (Orchidaceae)

Late floral ontogeny is studied in representative species of the genera of Epidendrum alliance to re-examine the systematic position of the controversial Microepidendrum subulatifolium. Series of late floral stages were sampled from M. subulatifolium, Caularthron bilamellatum, Barkeria uniflora and Epidendrum ciliare. The samples were prepared for scanning electronic microscopy. Several characters that were observed during late floral development in Barkeria, Epidendrum and Caularthron in the Epidendrum alliance such as curvature of the column, wings on the column, ontogeny of the anther, conspicuous striate ornamentation of the cuticle of the epidermis of the anther wall, characteristic actinocytic stomata and their location on the anther, shape and number of caudicles, and shape of clinandrium, are not shared with M. subulatifolium. These characters suggest that the correct systematic position of M. subulatifolium might be in the Encyclia alliance as previously suggested. We determined the polarity of character states for three attributes in the Epidendrum alliance. The polarity regarding the degree of fusion between the lip and column within the Epidendrum alliance goes from free lip in Caularthron, lip adnate to column-foot in Orleanesia, lip attached only to the base of the column and the rest of the lip appressed to the column-part but not united with it in Barkeria, and a completely fused lip and column in Epidendrum. For curvature of the column, the trend goes from initially straight in early developmental stages to arcuate. Striae in the cuticle of the epidermis of the anther evolve from smooth to sparse to very conspicuous with radial and parallel cells.

Deep evolutionary roots of strepsirrhine primate labyrinthine morphology

The cavity system of the inner ear of mammals is a complex three-dimensional structure that houses the organs of equilibrium and hearing. Morphological variation of the inner ear across mammals reflects differences in locomotor behaviour and hearing performance, and the good preservation of this structure in many fossil specimens permits analogous inferences. However, it is less well known to what extent the morphology of the bony labyrinth conveys information about the evolutionary history of primate taxa. We studied this question in strepsirrhine primates with the aim to assess the potential and limitations of using the inner ear as a phylogenetic marker. Geometric morphometric analysis showed that the labyrinthine morphology of extant strepsirrhines contains a mixed locomotor, allometric and phylogenetic signal. Discriminant analysis at the family level confirmed that labyrinthine shape is a good taxonomic marker. Our results support the hypothesis that evolutionary change in labyrinthine morphology is adequately described with a random walk model, i.e. random phenotypic dispersal in morphospace. Under this hypothesis, average shapes calculated for each node of the phylogenetic tree give an estimate of inner ear shapes of the respective last common ancestors (LCAs), and this information can be used to infer character state polarity. The labyrinthine morphology of the fossil Adapinae is close to the inferred basal morphology of the strepsirrhines. The inner ear of Daubentonia, one of the most derived extant strepsirrhines, is autapomorphic in many respects, but also presents unique similarities with adapine labyrinths.

Morphology and biogeography of Apiaceae subfamily Saniculoideae as inferred by phylogenetic analysis of molecular data

The phylogenetic placements of several African endemic genera at the base of Apiaceae subfamilies Saniculoideae and Apioideae have revolutionized ideas of relationships that affect hypotheses of character evolution and biogeography. Using an explicit phylogeny of subfamily Saniculoideae, we reconstructed the evolutionary history of phenotypic characters traditionally important in classification, identified those characters most useful in supporting relationships, and inferred historical biogeography. The 23 characters examined include those of life history, vegetative morphology, inflorescences, and fruit morphology and anatomy. These characters were optimized over trees derived from maximum parsimony analysis of chloroplast DNA trnQ-trnK sequences from 94 accessions of Apiaceae. The results revealed that many of these characters have undergone considerable modification and that traditional assumptions regarding character-state polarity are often incorrect. Infrasubfamilial relationships inferred by molecular data are supported by one to five morphological characters. However, none of these morphological characters support the monophyly of subfamilies Saniculoideae or Apioideae, the clade of Petagnaea, Eryngium and Sanicula, or the sister-group relationship between Eryngium and Sanicula . Southern African origins of Saniculoideae and of its tribes Steganotaenieae and Saniculeae are supported based on dispersal-vicariance analysis.

Seedling Diversity and the Homologies of Seedling Organs in the Order Poales (Monocotyledons)

Seedlings of monocots are much more diverse than those of other angiosperms, often with very derived character states. This makes morphological interpretation difficult. The morphology of seedlings of most of the 16 families of the Poales alliance are only incompletely known. The present study aims first to develop an unambiguous terminology for the description of monocotyledonous seedlings. This makes possible clear morphological comparisons and the use of homologous terms for organs. Finally, plotting of well defined characters onto a molecular tree allows the polarization of character states. Seedlings were grown in Petri dishes on moist filter paper under permanent light conditions and analysed using light and scanning electron microscopy. Only seeds collected at natural habitats or from plants with a well documented source were used. Seedling vouchers are deposited in the alcohol collection of Monocot seedlings in the Botanische Staatssammlung München (M). Based on an unambiguous terminology, seedlings of a great number of genera are described and presented as figures, representing all families of Poales except Ecdeiocoleaceae. Seedlings of Rapateaceae, Joinvilleaceae and Mayacaceae are described for the first time. Morphological comparisons reveal a plausible interpretation of even very modified organ structures, including those of the grass seedling. This study demonstrates that detailed studies of seedling morphology can provide interesting morphological insights and also new facts for phylogenetic analyses. However, the morphological diversity of seedlings in the monocots is as yet incompletely known, and in some, e.g. Alismatales or Zingiberales, the seedling structure is particularly poorly understood in terms of comparative morphology.

Fossil Calibration of Molecular Divergence Infers a Moderate Mutation Rate and Recent Radiations for Pinus

Silent mutation rate estimates for Pinus vary 50-fold, ranging from angiosperm-like to among the slowest reported for plants. These differences either reflect extraordinary genomic processes or inconsistent fossil calibration, and they have important consequences for population and biogeographical inferences. Here we estimate mutation rates from 4 Pinus species that represent the major lineages using 11 nuclear and 4 chloroplast loci. Calibration was tested at the divergence of Pinus subgenera with the oldest leaf fossil from subg. Strobus (Eocene; 45 MYA) or a recently published subg. Strobus wood fossil (Cretaceous; 85 MYA). These calibrations place the origin of Pinus 190-102 MYA and give absolute silent rate estimates of 0.70-1.31x10(-9) and 0.22-0.42x10(-9).site-1.year-1 for the nuclear and chloroplast genomes, respectively. These rates are approximately 4- to 20-fold slower than angiosperms, but unlike many previous estimates, they are more consistent with the high per-generation deleterious mutation rates observed in pines. Chronograms from nuclear and chloroplast genomes show that the divergence of subgenera accounts for about half of the time since Pinus diverged from Picea, with subsequent radiations occurring more recently. By extending the sampling to encompass the phylogenetic diversity of Pinus, we predict that most extant subsections diverged during the Miocene. Moreover, subsect. Australes, Ponderosae, and Contortae, containing over 50 extant species, radiated within a 5 Myr time span starting as recently as 18 MYA. An Eocene divergence of pine subgenera (using leaf fossils) does not conflict with fossil-based estimates of the Pinus-Picea split, but a Cretaceous divergence using wood fossils accommodates Oligocene fossils that may represent modern subsections. Because homoplasy and polarity of character states have not been tested for fossil pine assignments, the choice of fossil and calibration node represents a significant source of uncertainty. Based on several lines of evidence (including agreement with ages inferred using calibrations outside of Pinus), we conclude that the 85 MYA calibration at the divergence of pine subgenera provides a reasonable lower bound and that further refinements in age and mutation rate estimates will require a synthetic examination of pine fossil history.

Cladistic, phenetic and biogeographical analysis of the flightless dung beetle genus, Gyronotus van Lansberge (Scarabaeidae: Scarabaeinae), in threatened eastern Afrotropical forests

By virtue of their low vagility, flightless insects are useful indicators of biogeographical history. Relationships of the flightless dung beetle genus, Gyronotus, are of particular interest due to its Gondwanaland ancestry, distinctive relict distribution along the south-eastern seaboard of Africa, and its restriction to forests which are seriously threatened by exploitation. Because of the limited number of diagnostic morphological characters, it was necessary to code morphometric data in order to conduct distance and cladistic parsimony analysis of interspecific relationships in Gyronotus. There was a good correlation between relationships indicated by the dendrograms/cladograms and those determined by an examination of aedeagus character states both of which indicate a disjunction between south and east African species and a broad separation between northern and southern South African species. Comparison of the bilaterally asymmetrical aedeagi of Gyronotus with the symmetrical aedeagi of the sister genus, Anachalcos Hope, suggests geographical polarization of character states from greater plesiomorphy in east African Gyronotus to greater apomorphy in South African species, particularly in the southernmost element in which the aedeagus shows extreme asymmetry. Furthermore, body shape follows a similar geographical gradient in that the three Gyronotus species of tropical east Africa are significantly more elongate than the three ovoid, lowland/afromontane species of South Africa. An examination of historical factors suggests that this spatially-restricted distribution is the relict of a very old tropical lowland pattern. In extant taxa, the phylogenetic polarization is towards one of five main centres of afrotropical forest biodiversity in the geologically old Eastern Arc and the adjoining lowland forest (Swahili centre of endemism). Survivors from old lineages may be one reason for such centres of high biodiversity.

Spliceosomal Introns and Fish Phylogeny: A Critical Reanalysis

The currently available spliceosomal intron data were found to be of limited utility as phylogenetic characters for resolving the phylogeny of several clades of fishes. Phylogenetic relationships were inferred from a parsimony analysis of the distribution of introns among representatives of 18 major groups of vertebrates for seven genes. Phylogenetic signal of the spliceosomal intron data was limited to support for the monophyly of the Teleostei. The spliceosomal intron based phylogeny of B. Venkatesh, Y. Ning, and S. Brenner (in the Proceedings of the National Academy of Science, 1999) was evaluated and found to be fundamentally flawed. The analysis of B. Venkatesh, Y. Ning, and S. Brenner (in the Proceedings of the National Academy of Science, 1999) was compromised by errors in the treatment of missing and polymorphic data, the arbitrary exclusion of taxa, the assessment of homology, outgroups and rooting, the ordering and polarization of character states, and a failure to follow the logical implications of multiple equally parsimonious trees.

Embryology of Amborella (Amborellaceae): Descriptions and Polarity of Character States

Baill. which, based on recent analyses of multiple genes, was identified as the first branch in the angiosperm evolution. Comparisons with two other basal angiosperms (Nymphaeaceae and Illiciales), as well as with the other angiosperms, showed that most of the embryological features of Amborella are plesiomorphies. They include: the tetrasporangiate anther; the fibrous endothecium; the glandular tapetum composed of two-nucleate cells; two-celled mature pollen; formation of the hypostase; bitegmic and crassinucellate ovules; the Polygonum type embryo sac; ephemeral antipodal cells; a lack of vascular bundles in the integuments; ab intio Cellular type endosperm; non-pachychalzal ovule or seed; albuminous mature seed. Contrary to all previous descriptions, Amborella has hemianatropous, rather than anatropous or orthotropous, ovules. For the determination of the polarity of ovule curvature as well as of some other characters such as the presence or absence of the nucellar cap and the obturator, the formation of the micropyle, and seed coat structure, additional studies on Nymphaeaceae and Illiciales are needed.

The Tribal Position of Hypocalyptus Thunberg (Fabaceae)

The Tribal Position of Hypocalyptus Thunberg (Fabaceae)

Phylogenetic Affinities Among the Extant Malagasy Lemurs (Lemuriformes) Based on Morphology and Behavior

The difficulty in achieving a consensus on the phylogenetic relationships of lemuriform primates has been due largely to the lack of a lemur fossil record and to the lack of an appropriate outgroup that would facilitate polarization of character states. Recent findings allow us to polarize some of the bony characters, but to a large extent this problem still remains. In the past, phylogenetic analyses have focused on specialized character sets such as dentition or basicranial traits, or they have employed differential weighting schemes to a more variable set of characters. In the analysis presented here, I combined all relevant characters available in the literature into one data set but restricted my selection to those traits having discontinuous states and for which no contradictory coding schemes were published. I reduced the assumptions in this analysis by removing most external weighting and ordering effects on these data sets. The available data from the literature were supplemented with data from my own observations at the Duke University Primate Center. Data were collected for 25 characters and 20 taxa and were submitted to a cladistic analysis. Some important findings from this study include support for (1) a sister-group relationship between Lepilemur and the Indridae, (2) a sister-group relationship between the Lemuridae (except Varecia) and the Indridae/Lepilemur clade, (3) a monophyletic genus Eulemur, and (4) the exclusion of Varecia from the Lemuridae.

Phylogenetic Relationships Among American Species of Sesarma (Subgenus Armases) (Brachyura, Grapsidae)

The phylogeny of Armases, a subgenus of Sesarma, is analysed on the basis of morphological data. Polarity of character states was determined by means of outgroup comparisons. For the reconstruction of the proposed phylogenetic tree, nine out of the eleven known American Armases species were examined. The presence of shared synapomorphies suggests a monophyletic origin of the subgenus with Aratus pisonii, Sesarma (= Metasesarma) rubripes and the East Atlantic Sesarma elegans. Sesarma benedicti has a basal position in the phylogenetic tree. All other species are subdivided into three groups, called Aratus-, roberti- and cinereum-group. A new comparison with Sesarma haematocheir, species of Chiromantes, confirms that the species examined do not belong to this subgenus of Sesarma and supports the establishment of the new taxon Armases by Abele (1992).

Phylogeny of the Euhirudinea: Independent evolution of blood feeding by leeches?

The phylogenetic relationships of leeches were investigated by examining 22 species representative of the 10 euhirudinean familes in a cladistic analysis. Forty-five characters relating to internal and external morphology as well as cocoon deposition characteristics were used. Polarization of character states was accomplished using Acanthobdella peledina as the sister-taxon to the Euhirudinea. Two equally parsimonious solutions resulted. One was chosen as a preferred tree on the basis of defensible character state transformations. Previous speculations as to evolutionary branching patterns are largely consistent with the results obtained by cladistic analysis. Similarly, contemporary taxonomic groupings of leeches into higher taxonomic categories were found to be largely consistent with monophyletic groups identified in the analysis. The family Piscicolidae was found to be paraphyletic; elevating the constituent piscicolid subfamilies to the level of family is proposed. The origin of sanguivory as a life-history mode was investigated by optimizing this characteristic on the phylogenetic hypothesis, indicating the possibility of at least two origins of blood-feeding in the evolutionary history of leeches, depending largely on how the feeding biology of acanthobdellids is interpreted. Sanguivory is seen to have been lost at least twice.

New Marine Tardigrades from Hawaiian Beach Sand and Phylogeny of the Family Halechiniscidae

Two new species of marine interstitial arthrotardigrades, both members of a new genus, are described from Anahola Bay, Kauai, Hawaiian Islands. Dipodarctus n. gen. is characterized by long primary clavae situated ventral to short lateral cephalic cirri; small ovoid leg IV papillae with short terminal spines; and unequal toe-length patterns on feet IIII as compared to foot IV. Toes on foot IV are of Tanarctus-type with long medial toes, while feet I-III possess at least 3 equal, short toes. Dipodarctus borrori n. sp. has stubby, 2piece cephalic cirri; an unusual protrusible mouth cone; and outermost toe on feet I-III twice the length of remaining toes on these feet. Dipodarctus anaholiensis n. sp. has long, tapering cephalic cirri; all toes on feet I-III equal; and coarsely punctate cuticle. Dipodarctinae is erected as a new subfamily within the Halechiniscidae to include these animals. Unifying features of the subfamily include ventrally set primary clavae; short sensory papilla on leg IV; feet of legs I-III differing from foot of leg IV. Character-state polarities among the members of the subfamilies of Halechiniscidae are used to construct a cladogram in which two basic groups are distinguished primarily on the basis of toe-length patterns, claw features, and the shape of cephalic appendages. Additional key words: Tardigrada, Heterotardigrada, Arthrotardigrada, Dipodarctinae, Dipodarctus borrori, D. anaholiensis Unique hot spot origins coupled with modern accessibility have made the Hawaiian islands a major focus for studies of island ecology (e.g., a recent series of review articles introduced by Simon, 1987). However, the shallow-water, interstitial marine meiofauna there remains largely undescribed. This is the first published record of marine tardigrades from Hawaii. In fact, the literature provides little information on interstitial tardigrades from the entire Eastern Pacific. Infaunal tardigrades from the west coast of North America have been reported by McGinty (1969) and Pollock (1989). Salvat & Renaud-Mornant (1969) and Renaud-Mornant (1976, 1981) found shallow-water species among the Society Islands. Interstitial tardigrades from the Galapagos Islands have been described by Ax & Schmidt (1973) and especially by McKirdy et al. (1976) and from the coast of El Salvador by Schulz (1953). Finally, deep-water species have been reported by Renaud-Mornant (1981) and by Bussau (1992). Altogether, these reports account for 19 species in 13 genera. The purpose of this study was to provide initial taxonomic groundwork for a limited survey of the intertidal marine tardigrades from 3 islands in the Hawaiian group. During the course of this investigation, 2 new, related tardigrade species were found within a single beach at Anahola Bay, Kauai. They possessed features so unique as to constitute a new genus and to require the erection of a new subfamily. In order to view the new subfamily in perspective, I offer a discussion of possible phylogenetic relationships among halechiniscid subfamilies.

Suprafamilial relationships within marsupialia: Resolution and discordance from multidisciplinary data

Selected characters of the cranioskeletal, dental, neuroanatomical, reproductive, lymphoid, and developmental systems that are known for most or all extant marsupial families are reviewed and analyzed for their abilities to corroborate higher-level hypotheses of suprafamilial relationships among extant marsupials. In addition, relatively conservative nucleotides from the mitochondrial 12S rDNA gene (obtained from the recent study by Springeret al., J. Mammal. Evol. 2, 85–115, 1994) were incorporated into the same character analysis. The ancestral morphotype for each marsupial family and each character was reconstructed, using the reconstructed eutherian and therian morphotypes for outgroup comparisons. In addition, ontogenetic data, stratigraphic position of fossils, and form-functional considerations were used, whenever feasible, to assess character state polarity of anatomical traits. Despite missing data from some families and many genera, this preliminary and modified “total evidence” approach helps to identify several well corroborated higher taxa, including Diprotodontia, Vombatiformes, and Macropodoidea, and it provides modest support for Ameridelphia, Australidelphia, and Syndactyla. An important conclusion is that no single data set is capable of resolving all suprafamilial relationships among marsupials. Suggestions are also presented for future multidisciplinary approaches to help resolve several polychotomies that have remained resistant to phylogenetic analyses of single data sets.

New primitive carnivorans (Mammalia) from the Paleocene of western Canada, and their bearing on relationships of the order

ABSTRACT The earliest Carnivora are known from two families, the Miacidae, which retain M3/m3 and occur first in latest Paleocene (Clarkforkian) rocks, and the Viverravidae, which have lost M3/m3, but are known first in the middle Paleocene (Torrejonian). This paper describes two new genera and species of carnivorans, one (Pristinictis connata) a viverravid and the other (Ravenictis krausei) of uncertain familial affinities, from the early Tiffanian of Alberta and early Puercan of Saskatchewan, respectively; both have a molar structure more primitive than previously known for the order. The new carnivorans allow a reassessment of character state polarities in the early evolution of the Carnivora, thereby providing the opportunity for reexamination of the relationships of carnivorans to other eutherian orders. As a consequence of this study, it appears that carnivorans and creodonts share no uniquely derived character states of the dentition that might indicate they are sister-groups, and that carnivorans ...

Utility of Ontogenetic and Conventional Characters in Determining Phylogenetic Relationships of Saururaceae and Piperaceae (Piperales)

Morphological and developmental evidence is utilized in a phylogenetic analysis of Piperales. Best resolution of trees was obtained by combining ontogenetic data with conventional morphological data. Floral ontogeny provides a means to determine homology among character states as well as to provide additional characters not observable in mature flowers. Both Lundberg and outgroup rooting were performed using a hypothetical ancestor defined by general ontogenetic states in the former and by five taxa presumably related to the ingroup in the latter. Polarization of character states via ontogenetic generality principles is congruent with outgroup polarization. Saururaceae and Piperaceae are each monophyletic. Saururaceae are supported by three synapomorphies, with Saururus as the basal taxon. The other three saururaceous genera (Anemopsis, Houttuynia, Gymnotheca) share the derived character slates of syncarpy, stamen-carpel adnation, and an inferior or half-inferior ovary. Piperaceae are supported by seven synapomorphies with Zippelia as the basal taxon. Six other synapomorphies unite the remaining Piperaceae suggesting that Macropiper and Pothomorphe are specialized offshoots of the morphologically variable Piper. Numerous autapomorphies support Peperomia as a distinct and specialized offshoot within Piperaceae. Within the sister clades Saururaceae and Piperaceae, there are parallel reduction trends in floral organ number and in the sequence of floral organ initiation.

Evolutionary trends in the dentition of true lemmings (Lemmini, Cricetidae, Rodentia): functional‐adaptive analysis

This paper offers a functional analysis of structure and variation trends in the dentition of species of the tribe Lemmini Simpson, 1945. The striking differences in the structure, trends in variation and rate of evolution between the Lemmini and all other members of Arvicolinae can be understood from the quite different functioning of the masticatory apparatus. The polarity of character states in the dentition of the Lemmini is discussed. Suggested polarity is supported by the palaeontological and functional evidence. The distinctive means of increasing the efficiency of the masticatory apparatus seen in Lemmini not only reflects definite genetic history but can also be explained by their very unusual food specialization and the demands it imposes on the mechanics of their masticatory apparatus.

Systematic relationships of the Mantellinae Laurent 1946 (Anura Ranoidea)

Different opinions exist about mantelline relationships. Major causes are differences in observations on tarsals and carpals, and the fact that no consensus has been reached concerning the systematics of the other ranoid frogs, so making it difficult to determine the polarity of character states. Therefore a series of osteological characters was investigated in several ranoids, especially in the Mantellinae, and a cladogram of the “firmisternal” frogs was constructed. This cladogram splits into two main branches; the Microhyloidea containing the Sooglossidae, Dendrobatidae, Microhylidae and Hemisotidae (including the Brevicipitinae) and the Ranoidea comprising the Arthroleptidae, Hyperoliidae and Ranidae, including the Mantellinae and Rhacophorinae. With the arthroleptid-hyperoliid lineage as outgroup, the cladogram of the Ranidae shows a stepwise increase of derived features, each step being represented by a subfamily. These features, plus the intercalary element are shared by the monophyletic Mantellina...