Molecular phylogeny of arctoids (Mammalia: Carnivora) with emphasis on phylogenetic and taxonomic positions of the ferret-badgers and skunks

Phylogenetic relationships among the ferret-badger Melogale moschata, the skunk Mephitis mephitis, and 21 other arctoid carnivorans, representing Mustelidae (Mustelinae: Mustela, Martes, Gulo; Lutrinae: Enhydra; Melinae: Meles), Procyonidae (Procyon), and Ursidae (Ursus, Melursus), were evaluated through maximum-parsimony phylogenetic analysis of concatenated partial nucleotide sequences of the nuclear recombination-activating gene 1 (RAG1) and gene encoding interphotoreceptor retinoid-binding protein (IRBP). The analysis strongly supports Melogale as more closely related to a musteline-lutrine clade (containing Mustela and Enhydra) than to Meles or another musteline clade containing Martes and Gulo (causing Melinae and Mustelinae, as traditionally circumscribed, to be nonmonophyletic). This, together with known morphological and karyological evidence for nonmeline affinities of Melogale, justify the exclusion of the ferret-badgers from the monophyletic Melinae. Therefore, we recommend that Melogale be classified in a distinct mustelid subfamily, the monotypic Helictidinae. Our analysis also strongly supports an outgroup position of the skunks to a clade containing Procyonidae and the nonmephitine Mustelidae (causing Mustelidae, as traditionally circumscribed, to be paraphyletic). This position of the skunks agrees with results of most previous genetic studies. However, it is contradicted by known morphological evidence from both living and fossil taxa, as well as genetic evidence from protein electrophoresis. These consistently support the traditional placement of the skunks within the monophyletic Mustelidae (recently in a close relationship to Lutrinae). Therefore, we consider the recent elevation of the skunks to the level of family as premature, and recommend that this clade be left at the subfamily level (Mephitinae) within the family Mustelidae, pending further evidence.     

New insights into the evolution of intronic sequences of the beta-fibrinogen gene and their application in reconstructing mustelid phylogeny

Mustelidae is the largest and most diverse family in the order Carnivora. The phylogenetic relationships among the subfamilies have especially long been a focus of study. Herein we are among the first to employ two new introns (4 and 7) of the nuclear beta-fibrinogen gene to clarify these enigmatic problems. In addition, two previously available nuclear (IRBP exon 1 and TTR intron 1) and one mt (ND2) data sets were also combined and analyzed simultaneously with the newly obtained sequence data in this study. Detailed characterizations of the two intronic regions not only reveal the remarkable occurrences of short interspersed element (SINE) insertion events, providing a new example supporting the attractive hypothesis that attrition of an earlier retroposition may offer a proper environment for successive retropositions by forming a "dimer-like" structure, but also demonstrate their utility in the resolution of mustelid phylogeny. All of our analyses confirm the assemblage of Mustelinae, Lutrinae, and Melinae with confidence; moreover, two clades within Mustelinae were clearly recognized, i.e., genera Mustela and Martes. Notably, genus Martes of Mustelinae was found to branch off first, followed by Melinae and then a clade containing Lutrinae and genus Mustela of Mustelinae, indicating paraphyly of Mustelinae. In addition, Mephitinae diverges before the other mustelids and the monophyletic Procyonidae in all cases, supporting its elevation to a separate family. Additional independent genetic markers are still in need to resolve the trichotomy among Mephitinae and the other two carnivoran clades, Ailuridae and Procyonidae/non-mephitine Mustelidae.     

Molecular phylogenetic study on the origin and evolution of Mustelidae

The family Mustelidae, which consists of Mustelinae, Lutrinae, Melinae, and Taxidiinae, is the largest family among Carnivora and is a highly diverse group. Recent molecular phylogenetic studies have clarified the phylogenetic relations among Mustelidae, but there remain several unresolved problems, particularly concerning the deep branchings. Whereas many studies support the monophyly of Mustelidae+Procyonidae among Musteloidea, the relations between Mustelidae+Procyonidae, Ailuridae, and Miphitidae are still unclear. To address these problems, we inferred a tree on the basis of the sequences of mitochondrial genomes and of multiple nuclear genes using the maximum likelihood method. Our results strongly support the hypothesis that the Taxidiinae branched at first, followed by the branching of the Melinae. After that, Mustelinae diversified, and Lutrinae evolved within Mustelinae. With respect to the deep branchings in Musteloidea, the Ailuridae/Mephitidae monophyly tree and the Mephitidae-basal tree are indistinguishable in log-likelihood score, and this problem remains unresolved.     

鼬科动物线粒体DNA控制区结构分析

利用PCR技术获得紫貂(Martes zibellina)和黄喉貂(Martes flavigula)线粒体DNA控制区全序列,并结合从GenBank中下载的9种鼬科动物相应序列,用ClustalX排序后对控制区结构进行分析,识别出延长终止序列区、中央区和保守序列区3个区域,指出了一个终止相关序列ETAS1及8个保守序列(CSB-F、E、D、C、B、1、2和3),并给出了序列通式,在CSB1和CSB2之间发现不同形式的短重复序列.此外,以狼为外类群,应用邻接法构建鼬科线粒体控制区全序列的系统进化树,结果表明:臭鼬亚科最先从鼬科中分化出来,随后剩余类群分为两大支系,即貂属种类与貂熊聚为一支,并与獾亚科的狗獾形成姐妹群;另一支为水獭亚科的物种与鼬属的林鼬形成姐妹群,再与虎鼬聚在一起,狗獾与貂属的紫貂亲缘关系最近,水獭亚科与鼬属亲缘关系最近.     

Phylogenetic relationships and divergence times among mustelids (Mammalia: Carnivora) based on nucleotide sequences of the nuclear interphotoreceptor retinoid binding protein and mitochondrial cytochrome b genes

Phylogenetic relationships among 20 species-group taxa of Mustelidae, representing Mustelinae (Mustela, Martes, Gulo), Lutrinae (Enhydra), and Melinae (Meles), were examined using nucleotide sequences of the nuclear interphotoreceptor retinoid binding protein (IRBP) and mitochondrial cytochrome b genes. Neighbor-joining and maximum-parsimony phylogenetic analyses on these genes separately and combined were conducted. While IRBP performed better than cytochrome b in recovering more-inclusive clades, cytochrome b demonstrated more resolving power in recovering less-inclusive clades. Strong support was found for a close affinity of Enhydra with Mustela to the exclusion of Martes and Gulo (causing Mustelinae to be paraphyletic); the most-basal position of Mustela vison within Mustela, followed by Mustela erminea; an association of Mustela lutreola, Mustela itatsi, Mustela sibirica, and the subgenus Putorius (including Mustela putorius and Mustela eversmanii), to the exclusion of Mustela nivalis and Mustela altaica; and a basal position of Mustela itatsi to a clade containing Mustela sibirica and Putorius. Whereas cytochrome b strongly supported Mustela lutreola as the sister species to Putorius, IRBP strongly supported its basal placement to the Mustela itatsi-Mustela sibirica-Putorius clade. The low level of sequence divergence in cytochrome b between Mustela lutreola and Putorius is therefore a result of interspecific mitochondrial introgression between these taxa, rather than a recent origin of Mustela lutreola in a close relationship to Putorius. Time estimates inferred from IRBP and cytochrome b for mustelid divergence events are mostly in agreement with the fossil record.     

Conodonts Meet Cladistics: Recovering Relationships and Assessing the Completeness of the Conodont Fossil Record

A numerical cladistic analysis of the conodont family Palmatolepidae has been undertaken to determine the applicability of the technique to group-wide systematic revision. Results suggest a new hypothesis of relationships that is considerably more parsimonious than trees compatible with existing hypotheses of relationships, or trees that are even loosely constrained stratigraphically. This may occur either because the fossil record is incomplete, because taxon sampling for the cladistic analysis is low, or because the most parsimonious trees approximate the true tree less well than do stratigraphically-constrained trees (or because of a combination of these factors). Although more taxa and more characters would be preferable in choosing between these possibilities, the tree derived solely from morphological data is adopted. Thus, stratigraphic data can be used to test hypotheses of relationships and construct phylogenies; hypotheses of relationships can be used to test the completeness of the conodont fossil record. Existing schemes of classification within the Palmatolepidae are rejected because most groups within them are either polyphyletic or paraphyletic. A new scheme is presented. Character changes suggest correlated, progressive and mosaic evolution within the Palmatolepidae. Parsimony analysis of partitioned datasets indicates that more phylogenetic information can be recovered from S rather than P or M element positions, although data from all three positional groups are preferable to data from just one. Thus, multielement taxonomy is essential to the resolution of conodont interrelationships.     

Phylogeny, evolutionary history and taxonomy of the Mustelidae based on sequences of the cytochrome b gene and a complex repetitive flanking region

The Mustelidae is a diverse family of carnivores which includes weasels, polecats, mink, tayra, martens, otters, badgers and, according to some authors, skunks. Evolutionary relationships within the family are under debate at a number of different taxonomic levels, and incongruencies between molecular and morphological results are important. We analysed a total of 241 cytochrome b (cyt b) gene sequences and 33 sequences of a complex repetitive flanking region from 33 different species to compile an extensive molecular phylogeny for the Mustelidae. We analysed these sequences and constructed phylogenetic trees using Bayesian and neighbor‐joining methods that are evaluated to propose changes to the taxonomy of the family. The peripheral position of skunks in phylogenetic trees based on both loci suggests that they should be considered a separate family, Mephitidae. The subfamily Melinae is the basal group within the Mustelidae and trees based on the cyt b gene suggest that the American badger, Taxidea taxus, should be considered a separate monotypic subfamily, Taxidiinae. Otters classified within the genera Lutra, Amblonyx and Aonyx are grouped within the same clade in cyt b and combined partial cyt b and flanking region trees and show reduced levels of inter specific divergence, suggesting that they could be classified together under a single genus, Lutra. The Bayesian tree based on combined data from both loci supports the idea that subfamily Mustelinae is paraphyletic, as otters (subfamily Lutrinae) are included in this subfamily. Low levels of genetic divergence among European polecat, Mustela putorius, steppe polecat, Mustela eversmannii, and European mink, Mustela lutreola, suggest that these species could be considered subspecies within a single species, Mustela putorius. Our results are consistent with a rapid diversification of mustelid lineages in six different radiation episodes identified since the Early Eocene, the oldest events being the separation of subfamilies and the split of marten (Martes, Gulo) and weasel (Mustela) lineages in the Early Middle Miocene. The separation of New World from Old World lineages and the split of the remaining genera are estimated to have occurred in Late Miocene. The most recent events have been the differentiation of species within genera and this probably occurred in four radiation episodes at the end of Late Miocene, Early Pliocene, Late Pliocene and Pleistocene epochs.     

Phylogeny of the Anomala (Crustacea, Decapoda, Reptantia) based on the ossicles of the foregut

We present a cladistic analysis of the Anomala based on 66 ingroup species and 5 outgroup representatives. Based on a comparative analysis of the morphology of the foregut we scored 124 characters related to size, shape, and fusion of foregut ossicles and other foregut structures. Our parsimony analysis resulted in 30 equally parsimonious trees which differ mainly at the lower hierarchical level. Our study reveals two large clades within Anomala. One large clade consists of Galatheoidea and Chirostyloidea. The internal relationships show a monophyletic Porcellanidae nested within a group comprising paraphyletic Galatheidae, and Munididae as well as Munidopsidae. The other large clade contains Aegla as sister group to a monophyletic group consisting of the Hippoidea and a clade formed by Lomis and the Paguroidea. Coenobitidae are nested within paraphyletic Diogenidae and Lithodidae are nested within paraphyletic Paguridae. The results are discussed in the context of other morphological and molecular analyses. Furthermore, some aspects of carcinization are touched upon; in particular, an anomalan stem species with a, at least to some extent, ventrally folded pleon is suggested.     

Preliminary comments on a phylogenetic study of the order Diphyllidea van Beneden in Carus, 1863

The basis for a preliminary analysis of the relationships within the monophyletic Diphyllidea is outlined. Information on morphological characters and their interpretation within a phylogenetic context are presented. A cladistic analysis at the species level was conducted based on a matrix of 21 morphological characters. Character polarity was determined by taxonomic outgroup analysis relative to the basal orders, Pseudophyllidea and Haplobothriidea. The phylogeny for the diphyllideans was found to be poorly resolved based on characters currently available for evaluation. Computer assisted cladistic analysis found three equally parsimonious trees with a consistency index of 0.54. The topology of these trees shows that Ditrachybothridium macrocephalum is the basal taxon and the putative sister group for species of Echinobothrium; Macrobothridium rhynchobati is grouped among species of Echinobothrium. If the classification is to be consistent with this tree, M. rhynchobati should be included in the genus Echinobothrium. This observation should be carefully examined, considering the relative paucity of useful morphological characters currently available for this group.     

Evolutionary and biogeographic history of weasel-like carnivorans (Musteloidea)

We analyzed a concatenated (8492 bp) nuclear-mitochondrial DNA data set from 44 musteloids (including the first genetic data for Lyncodon patagonicus) with parsimony, maximum likelihood, and Bayesian methods of phylogenetic and biogeographic inference and two Bayesian methods of chronological inference. Here we show that Musteloidea emerged approximately 32.4-30.9 million years ago (MYA) in Asia, shortly after the greenhouse-icehouse global climate shift at the Eocene-Oligocene transition. During their Oligocene radiation, which proceeded wholly or mostly in Asia, musteloids diversified into four primary divisions: the Mephitidae lineage separated first, succeeded by Ailuridae and the divergence of the Procyonidae and Mustelidae lineages. Mustelidae arose approximately 16.1 MYA within the Mid-Miocene Climatic Optimum, and extensively diversified in the Miocene, mostly in Asia. The early offshoots of this radiation largely evolved into badger and marten ecological niches (Taxidiinae, Melinae, Mellivorinae, Guloninae, and Helictidinae), whereas the later divergences have adapted to other niches including those of weasels, polecats, minks, and otters (Mustelinae, Ictonychinae, and Lutrinae). Notably, and contrary to traditional beliefs, the morphological adaptations of badgers, martens, weasels, polecats, and minks each evolved independently more than once within Mustelidae. Ictonychinae (which is most closely related to Lutrinae) arose approximately 9.5-8.9 MYA, most likely in Asia, where it diverged into the Old World Ictonychini (Vormela, Poecilictis, Ictonyx, and Poecilogale) and New World Lyncodontini (Lyncodon and Galictis) lineages. Ictonychini presumably entered Africa during the Messinian Salinity Crisis (at the Miocene-Pliocene transition), which interposed the origins of this clade (approximately 6.5-6.0 MYA) and its African Poecilictis-Ictonyx-Poecilogale subclade (approximately 4.8-4.5 MYA). Lyncodontini originated approximately 2.9-2.6 MYA at the Pliocene-Pleistocene transition in South America, slightly after the emergence of the Panamanian land bridge that provided for the Great American Biotic Interchange. As the genera Martes and Ictonyx (as currently circumscribed) are paraphyletic with respect to the genera Gulo and Poecilogale, respectively, we propose that Pekaniaand Poecilictis be treated as valid genera and that "Martes"pennanti and "Ictonyx"libyca, respectively, be assigned to these genera.     

Phylogeny and jaw evolution in Gnathostomulida, with a cladistic analysis of the genera

Sørensen, M. V. (2002). Phylogeny and jaw evolution in Gnathostomulida, with a cladistic analysis of the genera. — Zoologica Scripta, 31, 461–480.
The relationships between the genera in Gnathostomulida were investigated in a computerized cladistic analysis. The data matrix comprised 55 morphological characters of sensory structures, the reproductive systems, and the hard mouthparts. The cladistic analysis produced four almost identical most parsimonious trees. The four trees differed by having different topologies within the family Gnathostomulidae. Based on the obtained trees, the following was concluded: (1) Filospermoidea and Bursovaginoidea are both monophyletic; (2) Scleroperalia is paraphyletic; (3) all known families except Onychognathiidae (Sterrer 1972) are monophyletic; (4) Onychognathiidae emend. comprises the genera Nanognathia, Onychognathia, Rastrognathia, Valvognathia and Vampyrognathia ; (5) Paucidentulidae and Onychognathiidae emend. branch off in the lower part of Bursovaginoidea; (6) the following two clades are monophyletic and appear as sister groups: Problognathiidae−Gnathostomulidae−Austrognathiidae and Gnathostomariidae− Goannagnathia −Mesognathariidae−Clausognathiidae−Agnathiellidae. Based on the character optimization it was suggested that the gnathostomulid jaw evolved from a relatively simple ancestral jaw belonging to the compact type or the open lamellar type. The fused lamellar type evolved from the open lamellar type. The ancestral dentarium resembled the arc type and evolved along two different evolutionary paths into the basket type and the row type.     

A phylogeny of the families of fossil and extant tetraodontiform fishes (Acanthomorpha, Tetraodontiformes), Upper Cretaceous to Recent

A data matrix is presented of 210 morphological characters (mostly osteological, some external) for 20 extant taxa of the ten Recent families of tetraodontiform fishes and 36 fossil tetraodontiforms. The oldest of these are from the Upper Cretaceous (95 Mya); most are from the Lower to Middle Eocene (50–58 Mya). There are two outgroup taxa (a zeiform and a caproid). A cladistic analysis of this matrix for only the extant taxa produced two equally parsimonious trees that call into question the monophyly of some of the previously accepted major higher-level tetraodontiform clades. Inclusion in the analysis of the large number of available fossil taxa helps to resolve relationships between family level clades. The new phylogenetic hypothesis, together with stratigraphic and biogeographical data, is used to discuss scenarios of the origin and evolution of the major clades of the order.  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society , 2003, 139 , 565−617.     

Type I STS markers are more informative than cytochrome B in phylogenetic reconstruction of the Mustelidae (Mammalia: Carnivora)

We compared the utility of five nuclear gene segments amplified with type I sequence-tagged site (STS) primers versus the complete mitochondrial cytochrome b (cyt b) gene in resolving phylogenetic relationships within the Mustelidae, a large and ecomorphologically diverse family of mammalian carnivores. Maximum parsimony and likelihood analyses of separate and combined data sets were used to address questions regarding the levels of homoplasy, incongruence, and information content within and among loci. All loci showed limited resolution in the separate analyses because of either a low amount of informative variation (nuclear genes) or high levels of homoplasy (cyt b). Individually or combined, the nuclear gene sequences had less homoplasy, retained more signal, and were more decisive, even though cyt b contained more potentially informative variation than all the nuclear sequences combined. We obtained a well-resolved and supported phylogeny when the nuclear sequences were combined. Maximum likelihood and Bayesian phylogenetic analyses of the total combined data (nuclear and mitochondrial DNA sequences) were able to better accommodate the high levels of homoplasy in the cyt b data than was an equally weighted maximum parsimony analysis. Furthermore, partition Bremer support analyses of the total combined tree showed that the relative support of the nuclear and mitochondrial genes differed according to whether or not the homoplasy in the cyt b gene was downweighted. Although the cyt b gene contributed phylogenetic signal for most major groupings, the nuclear gene sequences were more effective in reconstructing the deeper nodes of the combined tree in the equally weighted parsimony analysis, as judged by the variable-length bootstrap method. The total combined data supported the monophyly of the Lutrinae (otters), whereas the Melinae (badgers) and Mustelinae (weasels, martens) were both paraphyletic. The American badger, Taxidea taxus (Taxidiinae), was the most basal taxon. Because hundreds of type I STS primer sets spanning the complete genomes of the human and mouse have been published and thus represent many independently segregating loci, the potential utility of these markers for molecular systematics of mammals and other groups is enormous.     

A phylogenetic analysis of the monogenomic Triticeae (Poaceae) based on morphology

A cladistic analysis, primarily based on morphology, is presented from 40 diploid taxa representing the 24 monogenomic genera of the Triticeae. General problems related to the treatment of hybrids and supposedly allopolyploid heterogenomic taxa are highlighted. Special emphasis is given to taxa not traditionally included in Aegilops s.J. Most of the 33 characters used in the analysis are coded as binary. The only four multistate characters in the matrix are treated as unordered. Three diploid species of Bromus are used as outgroup. The number of equally parsimonious trees found is very large (approx. 170000; length = 107, ci = 0.36, ri = 0.75) and the strict consensus tree has an expectedly low level of resolution. However, most of the equally parsimonious trees owe their existence to an unresolved Aegilops clade. If this clade is replaced by its hypothetical ancestor, the number of equally parsimonious trees drops dramatically (48; length = 78, ci = 0.45, ri = 0.76). When trees for which more highly resolved compatible trees exist are excluded, only two trees remain. Bremer support is used as a measure of branch support. The trees based on morphology and on molecular data are largely incongruent.     

Phylogeny reconstruction in the neogene bryozoan metrarabdotos: A paleontologic evaluation of methodology

An adequate stratigraphic record can not only aid in both cladistic and stratophenetic reconstruction of phytogenies, but can also serve in estimating the temporal consistency of the resulting phylogenetic trees. For hypothetical data sets, cladistically constructed trees can be as consistent with the temporal distribution of sampled populations or species as those constructed stratophenetically. Empirical testing in taxonomic groups with sufficiently dense fossil records is needed to show whether, and under what conditions, this potential can be realized. A stratophenetic tree and cladistic trees based on several approaches to character weighting were constructed for Caribbean Neogene species of the bryozoan Metrarabdotos with multiple‐character data from closely spaced sequential populations. The modular morphology and highly punctuated evolutionary pattern of these species blur the distinction between continuous and discrete characters, so that all available characters are potentially of equal significance in establishing phytogenies, rather than just those with discrete states conventionally used in cladistic analysis. However, only the cladistic trees generated with all characters weighted to emphasize contribution to species discrimination have temporal consistencies that are clearly significant statistically and approach that of the stratophenetic tree in magnitude. These results provide a start toward establishing general guidelines for cladistic analysis of taxa with stratigraphie records too sparse for stratophenetic reconstruction.     

Cladistic analysis of the Sepsidae (Cyclorrhapha: Diptera) based on a comparative scanning electron microscopic study of larvae

The result of a phylogenetic analysis of the Sepsidae based on larval characters is presented. It is shown that cyclorrhaphan larvae can be as rich a source of characters as Nematocera immatures when investigated using an SEM. The cladistic analysis comprised fifty-two species in sixteen genera of the Sepsidae and five outgroup species and used fifty-seven morphological characters. It found seven parsimonious trees which only differed with respect to the arrangement of some species within the genus Themira. The basal dichotomies of the phylogenetic trees are particularly well supported, indicating the conservative nature of larval characters. Orygma is confirmed as the sister group of all the remaining sepsids, the Sepsinae. There is good larval evidence that Ortalischema is the sister group of all remaining Sepsinae and that the Toxopodinae constitute an early radiation within the Sepsidae. According to larval data, some genera are paraphyletic ( Themira, Palaeosepsis ), but adult characters appear to contradict these findings. Among the traditionally recognized higher taxa within the Sepsidae, Hennig's Themira species-group and Steysbal's Sepsini have to be rejected as polyphyletic. However, Hennig's Sepsis species-group is confirmed as monophyletic and will probably constitute one major element of a future phylogenetic system of the Sepsidae. States of the strongly modified fore-legs of some adult sepsid males are mapped onto the phylogenetic tree, largely confirming Šulc's ideas about the evolution of these features. The origin and evolution of male sternites with brushes and a gland on the tibiae of the males ('osmeterium') are discussed. Whereas adult characters point to a sister-group relationship between the Sepsidae and the Ropalomeridae, larval characters appear to indicate a sister-group relationship between the Coelopidae and the Sepsidae. The evidence for both hypotheses is critically evaluated.     

PHYLOGENY OF THE NEMERTEAN SUBCLASS PALAEONEMERTEA (ANOPLA, NEMERTEA)

Abstract— A cladistic analysis based on 50 morphological characters was performed for 49 of the 98 species currently assigned to the subclass Palaeonemertea (phylum Nemertea), and six additional undescribed species. Thirty-five species were excluded from the parsimony analysis because of the high number of unknowns in the character matrix, and one species since it was considered a nomen nudum . An initial analysis suggested that the subclass Hoplonemertea is the sistergroup to the clade Palaeo- and Heteronemertea and the ingroup cladograms are rooted using a paraphyletic outgroup based on this information. Seventy-two equally most parsimonious cladograms were found; the consistency index was low but tree-length distribution for the character set is skewed to the left, and the cladograms are invariably shorter than trees based on random data. These cladograms suggested a character transformation series for the cerebral organ where this complex character reappeared several times after being absent. We considered this biologically implausible and the final discussion is based on three cladograms, one step longer than the most parsimonious, where the evolution of this character appears to be more realistic. The cladistic analysis indicates that many previously recognized genera (e.g. Cephalothrix, Procephalothrix and Cephalotrichella ), and higher taxa, are paraphyletic. It furthermore indicates that the previously suggested hypothesis of the Archinemertea as a monophyletic sistertaxon to Palaeonemertea is unsupported.     

The Phylogenetic Position of Cetaceans: Further Combined Data Analyses, Comparisons with the Stratigraphic Record and a Discussion of Character Optimization

A recent total evidence analysis of the position of cetaceans(whales, dolphins and porpoises and extinct relatives) amongmammals indicated that the phylogeny of these taxa remains poorlyresolved. Molecular data show that 1) the order Artiodactyla(even-toed ungulates) is paraphyletic unless whales are includedwithin it and 2) that the traditional relationships of cladeswithin Artiodactyla are not supported. This controversy alsoaffects the position of a wholly extinct clade, Mesonychia,which has been argued to be the group of terrestrial mammalsmost closely related to whales. Here I update a previous totalevidence analysis by adding several hundred new informativemolecular characters from the literature. Even with the additionof these characters the phylogeny remains unresolved. All mostparsimonious trees, however, indicate a paraphyletic Artiodactylawith conflict existing over the exact sister taxon of Cetacea.Congruence between different equally parsimonious cladogramsand the stratigraphic record as measured using the modifiedManhattan Stratigraphic Measure shows that all of the competingtopologies, including those with a paraphyletic Artiodactyla,are significantly congruent with the stratigraphic record. Infossil taxa cladistic optimization can be used as an alternativeto "argument from design" (Lauder, 1996) to reconstruct behaviorand soft tissues that do not fossilize or osteological charactersthat have not preserved. In certain scenarios of cetacean phylogeny,optimization indicates that taxa such as the archaic whalesAmbulocetus and Pakicetus, and possibly mesonychians, are morecorrectly reconstructed without hair.     

On the evolution and morphology of the rotiferan trophi, with a cladistic analysis of Rotifera

The phylogeny of Rotifera was examined in different computer‐generated cladistic analyses, including Seisonidea, Bdelloidea, Flosculariacea, Collothecacea and all ploimids treated on family level. The analyses were based on a character matrix solely dealing with morphological characters, primarily based on the trophi morphology. Limnognathia maerski (Micrognathozoa), Rastrognathia macrostoma and Gnathostomula paradoxa (Gnathostomulida) were used as outgroups. The cladistic analysis performed by paup produced 288 most parsimonious trees. peewee analyses produced between 140 and 432 trees, depending on the concavity value. The monophyly of Eurotatoria, Monogononta and Ploima was confirmed in all obtained trees. All analyses suggested a division of Ploima into major clades. One clade corresponded to Transversiramida while the other contained all other ploimid taxa and recognized Antrorsiramida as a monophylum. Based on the obtained results a scenario for the trophi evolution is proposed. The analyses suggested that the presence of an incus is synapomorphic for Gnathifera while mallei are synapomorphic for Micrognathozoa and Rotifera. The ancestral rotifer trophi probably resembled those in Harringia (Asplanchnidae).     

裸藻类植物的分支系统学研究

本文选取了裸藻类的33个属级分类单位,以及它们的35个性状,利用分支系统学的原理和方法,对性状的演化极性进行了分析,同时对性状间的极性关系进行了和谐性分析,使性状间极性关系处在较为合理的状态,然后建立了分支分析的数据矩阵。应用徐克学建立的“演化极端结合法”进行微机运算．得简约系数远小于1(o．2159)的分支谱系图。根据分支诺系图对裸藻类的系统发育关系进行了探讨,井与已有的关于裸藻类分类系统和演化假设进行了比较。在此基础上按照裸藻类的亲缘关系及单系原则,对裸藻类的分类等级进行了划分,初步提出了建立1门1纲5目的分类系统。按照在分支谱系中的演化地位,认为裸藻属的5个亚属,明显地都应是独立的属。同时对裸藻类的共生起源与演化的关系也进行了讨论。