Molecular phylogeny of the armored catfish family Callichthyidae (Ostariophysi, Siluriformes)

The family Callichthyidae comprises eight genera of fishes widely distributed across the Neotropical region. In the present study, sequences of the mitochondrial genes 12S rRNA, 16S rRNA, ND4, tRNAHis, and tRNASer were obtained from 28 callichthyid specimens. The sample included 12 species of Corydoras, three species of Aspidoras, two species of Brochis, Dianema, Lepthoplosternum, and Megalechis, and two local populations of Callichthys and Hoplosternum. Sequences of Nematogenys inermis (Nematogenyidae), Trichomycterus areolatus, and Henonemus punctatus (Trichomycteridae), Astroblepus sp. (Astroblepidae), and Neoplecostomus paranensis, Delturus parahybae, and Hemipsilichthys nimius (Loricariidae) were included as the outgroup. Phylogenetic analyses were performed by using the methods of maximum parsimony and maximum likelihood. The results of almost all analyses were very similar. The family Callichthyidae is monophyletic and comprises two natural groups: the subfamilies Corydoradinae (Aspidoras, Brochis, and Corydoras) and Callichthyinae (Callichthys, Dianema, Hoplosternum, Lepthoplosternum, and Megalechis), as previously demonstrated by morphological studies. The relationships observed within these subfamilies are in several ways different from those previously proposed on the basis of morphological data. Molecular results were compared with the morphologic and cytogenetic data available on the family.     

Historical biogeography and cryptic diversity in the Callichthyinae (Siluriformes,Callichthyidae)

The family Callichthyidae, divided into the subfamilies Corydoradinae and Callichthyinae, contains more than 200 species of armoured catfishes distributed throughout the Neotropics, as well as fossil species dating from the Palaeocene. Both subfamilies are very widely distributed throughout the continent, with some species ranges extending across multiple hypothesized biogeographical barriers. Species with such vast geographical ranges could be made up of multiple cryptic populations that are genetically distinct and have diverged over time. Although relationships among Callichthyinae genera have been thoroughly investigated, the historical biogeography of the Callichthyinae and the presence of species complexes have yet to be examined. Furthermore, there is a lack of fossil‐calibrated molecular phylogenies providing a time frame for the evolution of the Callichthyinae. Here, we present a novel molecular data set for all Callichthyinae genera composed of partial sequences of mitochondrial and nuclear markers. These data were used to construct a fossil‐calibrated tree for the Callichthyinae and to reconstruct patterns of spatiotemporal evolution. All phylogenetic analyses [Bayesian, maximum likelihood and maximum parsimony (MP)] resulted in a single fully resolved and well‐supported hypothesis for the Callichthyinae, where Dianema is the sister group of all the remaining genera. Results suggest that the ancestry of most Callichthyinae genera originated in the Amazonas basin, with a number of subsequent ancestral dispersal events between adjacent basins. High divergences in sequences and time were observed for several samples of Hoplosternum littorale, Megalechis picta and Callichthys callichthys, suggesting that these species may contain cryptic diversity. The results highlight the need for a taxonomic revision of species complexes within the Callichthyinae, which may reveal more diversity within this relatively species‐poor lineage.     

Paedomorphosis and skull structure in Malagasy chamaeleons (Reptilia: Chamaeleoninae)

The phylogenetic analysis of skull characteristics, along with data derived from lung and hemipenial morphology, does not support monophyly of the predominantly terrestrial chamaeleons, Brookesiinae ( Brookesia plus Rhampholeon ), as sister-taxon of a monophyletic clade of arboreal chamaeleons, the Chamaeleoninae. Instead, the phylogenetic interrelationships of chamaeleonine lizards are ( Brookesia ("Rhampholeon" (Bradypodion, Chamaeleo) ). The monophyly of the genus Rhampholeon is not demonstrated. The arboreal chamaeleons form a monophyletic group comprising two genera, Bradypodion and Chamaeleo. Bradypodion may be placed as sister-group of the genus Chamaeleo , but its phyletic position and monophyly cannot at present be corroborated.
This study documents that there is a high degree of intraspecific variability in skull characters which may be due to paedomorphic reduction in the skull, especially of small species. Characters affected by a variable degree of ossification include the separation of a prefrontal fontanelle, the contact of the squamosal with the parietal, the size and position of the fenestra vestibuli, the degree of ossification in the basicranial rim of the fenestra, the extent of ossification of the pterygoid wing, and the shape of the skull roof as indicated by the bones forming the dorsal margin of the orbit. The closure of the lateral aperture of the occipital recess might indicate that miniaturization, and concomitant paedomorphosis, may have played a role in the initial phases of chamaeleonine phylogeny.     

A preliminary study on the phylogenetic relationships of Copelatus Erichson (Coleoptera: Dytiscidae: Copelatinae) based on larval chaetotaxy and morphology

The phylogenetic relationships of the diving-beetle (Dytiscidae) subfamily Copelatinae are not well known. Some authors postulated a sister-group relationship between Copelatus Erichson and the remaining Dytiscidae, relying mainly on the absence of a mandibular channel in Copelatus. Other authors suggested a more derived position of the genus. Larval characters have been underutilized in phylogenetic studies, mainly because the larvae of many taxa within the family and, in particular, within Copelatinae are unknown. A comprehensive approach aimed to study the phylogenetic placement of a member of this subfamily based on larval characters has not been produced so far. In this study, the phylogenetic relationships of Copelatus are explored based on a cladistic analysis of 24 taxa and 120 chaetotaxic and morphological characters from larvae. For this purpose, larvae of Copelatus longicornis Sharp are described and illustrated in detail for the first time, with particular emphasis on morphometry and chaetotaxy, with the latter being unexplored until now. The results support a derived position of Copelatus within Dytiscidae, with a sister-group relationship between this genus and a clade formed by the subfamilies Lancetinae, Coptotominae, Laccophilinae, Colymbetinae, Matinae, and Dytiscinae, and part of Agabinae. No evidence was found for a sister-group relationship between Copelatus and the remaining Dytiscidae so that the absence of a mandibular channel in this genus is likely a reduction. Copelatus is supported by three apomorphies within Dytiscidae: mandibular channel absent, internal margin of the stipes with three robust spinulae, and seta MX8 inserted subapically on the galea. Handling editor: K. Martens     

A phylogenetic analysis of the fungus-growing ants (Hymenoptera: Formicidae: Attini) based on morphological characters of the larvae

A phylogenetic hypothesis of the fungus-growing ants (subfamily Myrmicinae, tribe Attini) is proposed, based on a cladistic analysis utilizing forty-four morphological characters (109 states) of the prepupal worker larva. The fifty-one attine species analysed include representatives of eleven of the twelve currently recognized attine genera, excluding only the monotypic workerless parasite Pseudoatta ; the non-attines include two outgroups (species of the basal myrmicine genera Myrmica and Pogonomyrmex ), two myrmicine species presumed to be distantly related to the attines, and twelve species representing taxa that have been proposed by prior workers as possible sister groups of the Attini. There is strong character support for the monophyly of the Attini and for a sister-group relationship of the Attini and the Neotropical Blepharidatta brasiliensis. The Attini are divided into two distinct lineages, an 'apterostigmoid' clade (containing Apterostigma and Mycocepurus) and an 'attoid' clade (containing all other attine genera except Myrmicocrypta). The attine genus Myrmicocrypta appears to be paraphyletic with respect to these two groups; the species M.buenzlii in particular retains many attine plesiomorphies.
These results indicate that the fungus-growing behaviour had a single evolutionary origin in the ants. They also indicate that mycelium cultivation is plesiomorphic and that yeast cultivation is derived within the Attini, overturning the long-standing assumption that the yeast-growing Cyphomyrmex species are the most primitive Attini. Behavioural and ecological investigations into the origin and evolution of the fungus-growing behaviour might more profitably focus on species in the attine genus Myrmicocrypta , as well as those in the closely related non-attine genera Blepharidatta and Wasmannia.     

Hidden generic diversity in Neotropical birds: molecular and anatomical data support a new genus for the "Scytalopus"indigoticus species-group (Aves: Rhinocryptidae)

The genus Scytalopus is a species-rich and taxonomically complicated component of the Neotropical avian family Rhinocryptidae. Probably because Scytalopus is a superficially uniform assemblage, its monophyly has not been seriously questioned. We investigated phylogenetic relationships of a representative set of species in the genus using nuclear and mitochondrial DNA sequences as well as anatomical data, and provided the first test of its presumed monophyly by including in the analyses its hypothesized closest relatives (the genera Myornis, Eugralla, and Merulaxis) as well as most rhinocryptid genera. We found strong support for the paraphyly of the genus Scytalopus, with the Scytalopus indigoticus species-group forming a clade with Merulaxis. A well-supported clade including the genera Eugralla, Myornis, and the remaining Scytalopus was also recovered. Because these results were recovered independently and with strong support using mitochondrial and nuclear data, and were entirely consistent with anatomical data, we erect a new genus for the S.indigoticus species-group. These findings illustrate the importance of formally testing hypotheses of monophyly even for well-accepted groups of Neotropical birds.     

A combined morphological and molecular phylogeny of the genus Chironius Fitzinger, 1826 (Serpentes: Colubridae)

Chironius is one of the most speciose genera of the South American colubrid snakes. Although the genus represents a well‐known radiation of diurnal racers, its monophyly, affinities with other Neotropical colubrid genera, and intrageneric relationships are open questions. Here, we present a phylogenetic analysis of Chironius based on a data matrix that combines one nuclear (c‐mos) and two mitochondrial (12S and 16S rRNA) genes with 37 morphological characters derived from scutellation, skull, and hemipenial features. Phylogenetic relationships were inferred using maximum parsimony (MP) and maximum likelihood (ML). Our combined morphological and molecular analyses strongly support the monophyly of the genus Chironius and its sister‐group relationship with a clade formed by the genera Dendrophidion and Drymobius. Phylogenetic relationships within the genus Chironius is still controversial, although five clades are retrieved with medium to strong support. © 2014 The Linnean Society of London     

Phylogenetic analysis of the Silurian Retiolitidae

A cladistic, phylogenetic analysis of the Retiolitidae, using 18 genera and parataxa and 23 characters, reveals that two distinct clades can be recognized within this family, as well as a primitive stem-group that includes the genus Pseudoretiolites . One of the derived clades includes Pseudo-plegmatograptus, Stomatograptus and Retiolites , which are assigned to the revised subfamily Retiolitinae. The other derived clade, the early part of which shows a paraphyletic relationship, includes the remaining known genera Rotaretiofites s.l., Paraplectograptus s.l., Sokolovograptus, Plectograptus, Agastograptus, Spinograptus, Gothograptus, Eisenackograptus, Neogothograptus, Semiplectograptus, Plectodinemagraptus and Holoretiolites . These genera are all included within an expanded Plectograptinae. The biostratigraphic distribution of these taxa suggests that these two clades diverged from a Pseudoretiolites-like ancestor in mid-Aeronian time.     

On the systematic position of Catocala Schrank (Lepidoptera: Noctuidae)

The Holarctic genus Catocala Schrank is argued to belong to an otherwise mainly Ethiopian and Oriental clade consisting, in addition to this genus, of Audea Walker, Crypsotidia Rothschild, Hypotacha Hampson, Tachosa Walker and Ulotrichopus Wallengren. The principal synapomorphy is a distinctively sclerotized, elongate ovipositor. A numerical phylogenetic analysis of this group based on fifty-five characters suggests that Catocala may be paraphyletic, a subset of species being the closest relatives of Ulotrichopus. Catocala and Ulotrichopus together appear to be the sister-group of the remaining four genera. Audea fatilega Felder & Rogenhofer is found to have the characters of Ulotrichopus.     

Phylogenetic relationships and limb loss in sub-Saharan African scincine lizards (Squamata: Scincidae)

Skinks are the largest family of lizards and are found worldwide in a diversity of habitats. One of the larger and more poorly studied groups of skinks includes members of the subfamily Scincinae distributed in sub-Saharan Africa. Sub-Saharan African scincines are one of the many groups of lizards that show limb reduction and loss, and the genus Scelotes offers an excellent opportunity to look at limb loss in a phylogenetic context. Phylogenetic relationships were reconstructed for a total of 52 taxa representing all subfamilies of skinks as well as other Autarchoglossan families using sequence from six gene regions including; 12S, 16S, and cytochrome b (mitochondrial), as well as alpha-Enolase, 18S, and C-mos (nuclear). The family Scincidae is recovered as monophyletic and is the sister taxon to a (Cordylidae+Xantusiidae) clade. Within skinks the subfamily Acontinae is monophyletic and sister group to all remaining skinks. There is no support for the monophyly of the subfamilies Lygosominae and Scincinae, but sub-Saharan African scincines+Feylinia form a well supported monophyletic group. The monophyly of Scelotes is confirmed, and support is found for two geographic groups within the genus. Reconstructions of ancestral states for limb and digital characters show limited support for the reversal or gain of both digits and limbs, but conservative interpretation of the results suggest that limb loss is common, occurring multiple times throughout evolutionary history, and is most likely not reversible.     

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.     

Phylogenetic relationships of glyptosternoid fishes (Siluriformes: Sisoridae) inferred from mitochondrial cytochrome b gene sequences

To explore phylogenetic relationships among glyptosternoid fishes, we determined nucleotide sequences of the complete mitochondrial cytochrome b gene region (1138 base pair). Thirteen species of glyptosternoid fishes and six species of non-glyptosternoids represent 10 sisorid genera were examined. Molecular phylogenetic trees were constructed using the maximum parsimony, minimum evolution, maximum likelihood, and Bayesian methods. Bayesian and maximum likelihood analyses support the monophyly of glyptosternoids, but our hypothesis of internal relationships differs from previous hypothesis. Results indicated that glyptosternoid is a monophyletic group and genera Glyptosternum and Exostoma are two basal species having a primitive position among it. Genera Euchiloglanis and Pareuchiloglanis form a sister-group. Then they form a sister-group with Pseudexostoma plus Oreoglanis. Our result also found that Pareuchiloglanis anteanalis might be considered as the synonyms of Parechiloglanis sinensis, and genus Euchiloglanis might have only one valid species, Euchiloglanis davidi.     

Dracula ant phylogeny as inferred by nuclear 28S rDNA sequences and implications for ant systematics (Hymenoptera: Formicidae: Amblyoponinae)

Ants are one of the most ecologically and numerically dominant families of organisms in almost every terrestrial habitat throughout the world, though they include only about 1% of all described insect species. The development of eusociality is thought to have been a driving force in the striking diversification and dominance of this group, yet we know little about the evolution of the major lineages of ants and have been unable to clearly determine their primitive characteristics. Ants within the subfamily Amblyoponinae are specialized arthropod predators, possess many anatomically and behaviorally primitive characters and have been proposed as a possible basal lineage within the ants. We investigate the phylogenetic relationships among the members of the subfamily, using nuclear 28S rDNA sequence data. Outgroups for the analysis include members of the poneromorph and leptanillomorph (Apomyrma, Leptanilla) ant subfamilies, as well as three wasp families. Parsimony, maximum likelihood, and Bayesian analyses provide strong support for the monophyly of a clade containing the two genera Apomyrma+Mystrium (100% bpp; 97% ML bs; and 97% MP bs), and moderate support for the monophyly of the Amblyoponinae as long as Apomyrma (Apomyrminae) is included (87% bpp; 57% ML bs; and 76% MP bs). Analyses did not recover evidence of monophyly of the Amblyopone genus, while the monophyly of the other genera in the subfamily is supported. Based on these results we provide a morphological diagnosis of the Amblyoponinae that includes Apomyrma. Among the outgroup taxa, Typhlomyrmex grouped consistently with Ectatomma, supporting the recent placement of Typhlomyrmex in the Ectatomminae. The results of this present study place the included ant subfamilies into roughly two clades with the basal placement of Leptanilla unclear. One clade contains all the Amblyoponinae (including Apomyrma), Ponerinae, and Proceratiinae (Poneroid clade). The other clade contains members from subfamilies Cerapachyinae, Dolichoderinae, Ectatomminae, Formicinae, Myrmeciinae, and Myrmicinae (Formicoid clade).     

Redefinition and phylogenetic relationships of the family Pinguipedidae (Teleostei: Perciformes)

The phylogenetic relationships of the family Pinguipedidae plus the genus Cheimarrichthys von Haast, 1874, were studied to redefine the family. Based on a phylogenetic analysis using derived characters belonging to 21 transformation series, accepting the monophyly of Pinguipedidae plus Cheimarrichthys provisionally for the operational procedure of the analysis, it was hypothesized that Cheimarrichthys is not closely related to Parapercis Bleeker, 1863, although these genera had been considered as having a close affinity. Although the Pinguipedidae and Cheimarrichthys share nine derived characters, it was determined that these characters are also found in other trachinoid families. In addition, several families, such as the Leptoscopidae, Uranoscopidae, and Trichodontidae, have many more derived characters in common with Cheimarrichthys than the pinguipedids have with that genus. The conclusion drawn here is that it is not parsimonious to recognize the monophyly of the Pinguipedidae and Cheimarrichthys based on these nine derived characters, and that these characters are not compelling enough to link these groups. The redefined Pinguipedidae is proposed to include the following five genera: Parapercis, Prolatilus Gill, 1865, Pinguipes Cuvier, 1829, Pseudopercis de Miranda-Ribeiro, 1903, and Kochichthys Kamohara, 1960. Cheimarrichthys, excluded from the Pinguipedidae, is put into its own family, Cheimarrichthyidae.     

Phylogenetic position of Apostasia and Neuwiedia (Orchidaceae)

JUDD, W. S., STERN, W. L. & CHEADLE, V. I. 1993. Phylogenetic position of Apostasia and Neuwiedia (Orchidaceae). Cladistic analyses of the phylogenetic relationships of selected orchid taxa were conducted in order to assess the phylogenetic position of Apostasia and Neuwiedia (Orchidaceae: Apostasioideae). These analyses employed newly available anatomical characters, along with several morphological features that had been used in recent phylogenetic analyses of Orchidaceae. Our analyses indicate that Apostasia is more closely related to Neuwiedia than it is to Cypripedioideae. The two genera comprise an apostasiad clade; this clade is the sister-group to a clade including Cypripedioideae and monandrous orchids. The apostasiad clade is diagnosed by the derived features of operculate pollen colpi, Apostasia-type seeds, and vessel members with simple perforation plates. Of these, the presence of simple perforation plates is considered to be the most significant phylogenetically. Therefore, the apostasiads should not be considered ancestral to the remaining orchid groups. Vessel members of the monandrous orchids, as well as the cypripediads, are multiperforate–the hypothesized ancestral state based on the condition in Hypoxidaceae.     

Phylogenetic relationships within the aquatic snail genus Tryonia: implications for biogeography of the North American Southwest

We examined the phylogenetic relationships among 23 species of the North American aquatic snail genus Tryonia (Hydrobiidae), 10 additional representatives of the subfamily Cochliopinae, and two outgroups. Maximum parsimony analysis of a 601-base-pair sequence from the mitochondrial COI gene did not support monophyly of the genus nor its subgenus Paupertryonia. A clade composed of the type species of Tryonia and 16 congeners was strongly supported by the COI data and congruent with recently discovered variation in female genitalic morphology. This "true Tryonia" clade included two large western subclades having a sister-group relationship. The phylogenetic structure of one of these subclades is congruent with vicariant events associated with late Neogene history of the lower Colorado River drainage. The other subclade mirrors development of the modern Rio Grande rift and inception of modern topography in the southwestern Great Basin during the late Neogene. Both subclades are represented in the composite Tryonia fauna of the Amargosa River basin, whose assembly is attributed to the complex geological history of the Death Valley region.     

The phylogenetic placement of Hollandichthys Eigenmann 1909 (Teleostei: Characidae) and related genera

The phylogenetic relationships among characids are complex with many genera remaining of uncertain systematic position inside the family. The genus Hollandichthys is one of these problematic genera. It has been considered as incertae sedis inside this family until two recently published phylogenies, one morphological and one molecular, arrived at alternative hypothesizes as to the relationships of Hollandichthys with Pseudochalceus or Rachoviscus, respectively. In this paper, we infer the phylogenetic relations of these taxa based on five genes (three mitochondrial - COI, ND2 and 16S; and two nuclear - Sia and Trop), totaling up to 2719 bp. The 41 analyzed species in the Characidae include four incertae sedis characid taxa once hypothesized as related to Hollandichthys, but never analyzed in a single phylogeny (Rachoviscus, Pseudochalceus, Nematocharax and Hyphessobrycon uruguayensis). Here we propose Rachoviscus as the sister-group of Hollandichthys, grouped in the large clade C previously defined, along with the remaining incertae sedis taxa studied here. In addition, we support the evidence that insemination evolved independently at least three times in the Characidae.     

Phylogenetic relationships in European erpobdellid leeches (Hirudinea: Erpobdellidae) inferred from restriction-site data of the 18S ribosomal gene and ITS2 region

The PCR-amplified 185 rRNA gene and ITS2 region were used for a restriction-site analysis to infer phylogenetic relationships among European representatives of the leech family Erpobdellidae and to test the phylogenetic reliability of the morphological characters used in this family till now. Fragment patterns produced by 11 restriction endonucleases in the 18S rRNA gene and by nine in the ITS2 region showed a higher interspecific variation in the latter than in the former genome component. No intraspecific variation could be detected, even among geographically very distant populations, except for the two supposed subspecies Trocheta b. bykowskii and T. b. krasense . The estimated overall nucleotide divergence (d) was lower in the genus Erpobdella (d = 0.015–0.061) than in the genera Dina and Trocheta (d = 0.049–0.090). E. testacea and E. monostriata do not seem to be as closely related to each other as previously thought; their pairwise nucleotide divergence (0.061) is highest within the genus Erpobdella . The nucleotide divergence between T. b. bykowskii and T. b. krasense (0.090), which greatly resemble each other morphologically, was surprisingly high. Phylogenetic trees were inferred via neighbour-joining and maximum parsimony methods. The trees support the monophyly of Erpobdellidae and the subdivision into two groups according to the pattern of annulation (the Erpobdella clade and the Dina-Trocheta clade). Further subdivision based on annulation patterns and other morphological characters is not supported. There was no molecular evidence for the monophyly of the genus Dina and the monophyly of the genus Trocheta .     

Ontogeny and phylogeny of Brownleea (Orchidoideae: Orchidaceae)

The phylogeny of the African orchidoid genus Brownleea was investigated, using morphological characters. It has been suggested that the genus may be of hybrid origin, a hypothesis supported by the presence of two very different types of stigma ontogenies. Morphological investigations of all the species revealed that two species have stigmas derived from all three carpel apices, the 'normal' situation in the Orchidaceae. The remaining five species have stigmas derived from only the median carpel, a very unusual situation found in the Coryciinae. A phylogenetic analysis of all available morphological data for all species supports the monophyly of the genus. based on several distinct synapomorphies. The variation in stigma ontogeny may be due either to parallelism, or to an earlier hybridization event. The analysis supported the recognition of several distinct groupings within Brownleea . Two of these groupings are supported irrespective of which putative parent is used as sister-group to the genus, while a third grouping is dependent on the use of the as sister-group.     

Limb myology and phylogenetic relationships in the superfamily Dipodoidea (birch mice, jumping mice, and jerboas)

Limb muscles were dissected in seven genera, representing all six superfamilies, of dipodoid rodents and myoloic characters were used to construct a phylogenetic hpothesis of relationships within this cfade. Mologic differences among genera suported tie monophyly of the superfamily Dipodoidea reLtive to the outrou taxon and reveaEd thatSicista is the sister group to all other zapodid and dipodid enera. Tkis picement of Sicista differs markedly from its position in previous classifications where it has been regarded merely as a primitive zapodid genus. The phlograrn based on rnyologic characters also indicated that Cardiocranius is not a rimitive dipodid genus; it is the sister group to the subfamily Dipodinae. Although myologic differences among taxa were not sufficient to warrant the continued separation of zaodids and dipodids into two families, a new classification that places Sicista in its own family, ficistidae, and places the remaining zaodids and dipodids in the family Dipodidae, is proposed. Differences in karyology, genitaP morholoy, and postcranial osteological characters among dipodoid rodents are discussed in light or this pjylogeny.