The phylogenetic position of the Pterosauria within the Archosauromorpha

In recent years the hypothesis that pterosaurs were the major sister-group of dinosaurs and a closely-linked hypothesis that pterosaurs evolved flight from the ground up have gained general acceptance. A cladistic analysis of the Archosauromorpha using characters presented by previous workers results in a single most parsimonious tree with the Pterosauria as the major sister-group of the Dinosauria. However, that sister-group relationship is supported only by a suite of hindlimb characters that are correlated with bipedal digitigrade locomotion in dinosaurs. In pterosaurs the characters have been interpreted as correlates of bipedal cursorial locomotion, arboreal leaping, or involvement of the hindlimb in the wing. The homology of those characters in dinosaurs and pterosaurs cannot be supported. Reanalysis of the data after exclusion of those hindlimb characters results in most parsimonious trees with the Pterosauria as the sister-group of the Erythrosuchidae + Proterochampsidae + Euparkeria + Archosauria, in that order. This sister-group relationship is supported by a diverse assemblage of functionally independent skeletal characters from all regions of the skeleton. The results of the analysis cast doubt on the hypothesis that pterosaurs evolved flight from the ground up.     

Classification and phylogeny of the diapsid reptiles

Reptiles with two temporal openings in the skull are generally divided into two groups–the Lepidosauria (lizards, snakes, Sphenodon , 'eosuchians') and the Archosauria (crocodiles, thecodontians, dinosaurs, pterosaurs). Recent suggestions that these two are not sister-groups are shown to be unproven, whereas there is strong evidence that they form a monophyletic group, the Diapsida, on the basis of several synapomorphies of living and fossil forms. A cladistic analysis of skull and skeletal characters of all described Permo-Triassic diapsid reptiles suggests some significant rearrangements to commonly held views. The genus Petrolacosaurus is the sister-group of all later diapsids which fall into two large groups–the Archosauromorpha (Pterosauria, Rhynchosauria, Prolacertiformes, Archosauria) and the Lepidosauromorpha (Younginiformes, Sphenodontia, Squamata). The pterosaurs are not archosaurs, but they are the sister-group of all other archosauromorphs. There is no close relationship between rhynchosaurs and sphenodontids, nor between Prolacerta or Tanystropheus and lizards. The terms 'Eosuchia', 'Rhynchocephalia' and 'Protorosauria' have become too wide in application and they are not used. A cladistic classification of the Diapsida is given, as well as a phylogenetic tree which uses cladistic and stratigraphic data.     

The phylogenetic relationships and natural classificition of the Vespoidea (Hymenptera)

Abstract. Phylogenetic relationships of the subfamilies and tribes of the Vespoidea (= Diploptera) are investigated using cladistic methods. A natural classification is proposed, sequencing seven tribes in six subfamilies within the single family Vespidae. Euparagia is the sister-group of the rest of the Vespidae. The Gayellinae and Masarinae are sister-groups, and are reduced in rank to tribes within the subfamily Masarinae. This is the sister-group of the Eumeninae + Stenogastrinae + Polistinae + Vespinae. The Zethinae is a paraphyletic group; both it and the Raphiglossinae are deleted and included in the Eumeninae. The Stenogastrinae is regarded as the sister-group of the Vespinae + Polistinae.     

Evolution of metatherian and eutherian (mammalian) characters: a review based on cladistic methodology

Cladistic methodology is used to test the hypothesis that three major monophyletic groups exist among living mammals–the oviparous monotremes (Prototheria), and the viviparous marsupials (Metatheria) and placentals (Eutheria). Evaluation is made of the polarity (i.e. the direction of change in a primitive-to-derived sequence) of numerous characters which distinguish some or all of these groups, and of the usefulness of these characters in phylogenetic inference. An attempt is made to establish the state of these characters in the common Late Jurassic-Early Cretaceous therian ancestor of marsupials and placentals.
It is concluded that the most basic division of the Mammalia is the dichotomy into the subclasses Prototheria (including Monotremata, Multituberculata, Triconodonta, Docodonta) and Theria (including Metatheria, Eutheria, Pantotheria and Symmetrodonta). Two major groups exist among living viviparous mammals, the Metatheria and Eutheria; in a cladistic framework these are sister-groups. It is demonstrated that there is no special (sister-group) relationship between monotremes and marsupials, and there is no justification for placing them in a group Marsupionta.     

Phylogenetic systematics of the reptantian Decapoda (Crustacea, Malacostraca)

Although the biology of the reptantian Decapoda has been much studied, the last comprehensive review of reptantian systematics was published more than 80 years ago. We have used cladistic methods to reconstruct the phylogenetic system of the reptantian Decapoda. We can show that the Reptantia represent a monophyletic taxon. The classical groups, the 'Palinura', 'Astacura' and 'Anomura' are paraphyletic assemblages. The Polychelida is the sister-group of all other reptantians. The Astacida is not closely related to the Homarida, but is part of a large monophyletic taxon which also includes the Thalassinida, Anomala and Brachyura. The Anomala and Brachyura are sister-groups and the Thalassinida is the sister-group of both of them. Based on our reconstruction of the sister-group relationships within the Reptantia, we discuss alternative hypotheses of reptantian interrelationships, the systematic position of the Reptantia within the decapods, and draw some conclusions concerning the habits and appearance of the reptantian stem species.     

Relationship of Nandinia binotata (Gray) to the Superfamily Feloidea (Mammalia, Carnivora)

The phylogenetic relationship between Nandinia binotata and Feloidea is analysed by the cladistic method, based on a literature review of osteological characters used in systematic works on carnivores for more than a century. The reduced or lost postglenoid foramen is a synapomorphy that define Nandinia and Feloidea as a monophyletic group. Nandinia does not have an ectotympanic septum in the bulla nor a paroccipital process nested with the posterior wall of the bulla, which are autapomorphies for the Feloidea. Thus it is hypothesized that Nandinia binotata has a sister-group relation to Feloidea. The cartilaginous caudal entotympanic is an autapomorphy for Nandinia.     

Remarks on the family-level phylogeny of butterflies (Insecta, Lepidoptera, Rhopalocera)

1. Available evidence on butterfly family-level relationships is re-examined according to the principles of phylogenetic (cladistic) systematics. 2. The assumption of a sister-group relationship between the Hesperioidea and Papilionoidea seems a reasonably substantiated working hypothesis. 3. The Papilionoid families Papilionidae, Pieridae and Lycaenidae sensu Ehrlich (1958) are definable as monophyletic entities; of Ehrlich 's two remaining families, Nymphalidae and Libytheidae, the former is paraphyletic in terms of the latter. 4. The interrelationships between the Papilionoid families may be presented as Papilionidae + (Pieridae + [Lycanidae + Nymphalidae]). 5. In a phylogenetic system any given arrangement of taxa is either correct or not: Contrary to the pheneticists' view (Ehrlich and Ehrlich 1967) phylogenetic systematists cannot accept the existence of a multitude of valid classifications.     

Squamate phylogeny and the relationships of snakes and mosasauroids

Cladistic analysis of extant and fossil squamates (95 characters, 26 taxa) finds the fossil squamate, Coniasaurus Owen, 1850, to be the sister-group of the Mosasauroidea (mosasaurs and aigialosaurs). This clade is supported in all 18 shortest cladograms (464 steps; CI 0.677; HI 0.772) by nine characters of the dermatocranium, maxilla, and mandible. A Strict Consensus Tree of the 18 shortest trees collapses to a basal polytomy for most major squamate clades including the clade (Coniasaurus, Mosasauroidea). A Majority Rule Consensus Tree shows that, in 12 of 18 shortest cladograms, the clade Coniasaurus- Mosasauroidea is the sister-group to snakes (Scolecophidia (Alethinophidia, Dinilysia); this entire clade, referred to as the Pythonomorpha ([[Scolecophidia [Alethinophidia, Dinilysia]], [Coniasaurus, Mosasauroidea]]) is the sister-group to all other scleroglossans. Pythonomorpha is supported in these 12 cladograms by nine characters related to the lower jaw and cranial kinesis. In 6 of 18 shortest cladograms, snakes are the sister-group to the clade (Amphisbaenia (Dibamidae (Gekkonoidea, Eublepharidae))). None of the cladograms support the hypothesis that coniasaurs and mosasauroids are derived varanoid anguimorphs. Two additional analyses were conducted: (1) manipulation and movement of problematic squamate clades while constraining ‘accepted’ relationships; (2) additional cladistic analyses beginning with extant taxa, and sequentially adding fossil taxa. From Test I, at 467 steps, Pythonomorpha can be the sister-group to the Anguimorpha, Scincomorpha, ‘scinco-gekkonomorpha’ [scincomorphs, gekkotans, and amphibaenids-dibamids]. At 471 steps Pythonomorpha can be placed within Varanoidea. Treating only mosasauroids and coniasaurs as a monophyletic group: 469 steps, mosasauroids and coniasaurs as sister-group to Anguimorpha; 479 steps, mosasauroids and coniasaurs nested within Varanoidea. Test II finds snakes to nest within Anguimorpha in a data set of only Mosasauroidea + Extant Squamates; the sistergroup to snakes + anugimorphs is (Amphisbaenia (Dibarnidae (Gekkonoidea, Eublepharidae))). No one particular taxon is identified as a keystone taxon in this analysis, though it appears truc that fossil taxa significantly alter the structure of squamate phylogenetic trees.     

Cladistics of the Spermatophyta

A cladistic interpretation of seed plant phylogeny is presented that supports the traditional morphological hypothesis: [Cycadales-(Ginkgoales-(Coniferales-(Gnetales-Angiosperms)))]. Gnetales and Angiosperms are supported as sister groups of theAnaspermae. A sister-group relationship between Coniferales and Ginkgoales represents a paraphyletic group, because Coniferales and Anaspermae share a common ancestry (Mesospermae). Ginkgoales and Mesospermae are sister groups of theCladospermae. Cycadales are supported as the most archaic Spermatophyta.A posteriori consideration of fossil taxa supports the conclusion that data from the fossil record are useful for confirming plesiomorphies of extant taxa. Fossil taxa with apomorphic character states are discussed as biasing for superficial accelerated transformations, which are probably unacceptable from the standpoint of morphological homology.     

ORIGINS AND RELATIONSHIPS OF TROPICAL NORTH AMERICA IN THE CONTEXT OF THE BOREOTROPICS HYPOTHESIS

The boreotropics hypothesis postulates a preferential tropical biotic interchange between North America and Eurasia during the early Tertiary that was directed by Eocene thermal maxima and the close proximity of these two continental plates. This preferential interchange occurred at a time when South America was geologically and biotically isolated. A prediction of this hypothesis posits that a taxon with a present-day center of diversity in tropical North America, and with an early Tertiary fossil record from any region there, has a high probability of having sister-group relatives in the Paleotropics and derived relatives in South America. We propose a test of this prediction with phylogenetic studies of two pantropical taxa of Leguminosae that have early Tertiary North American fossil records. Our findings are consistent with the boreotropics hypothesis, and additional evidence suggests that many tropical elements in North America could be descendants of northern tropical progenitors. Ramifications of this hypothesis include the importance of integrating the fossil record with cladistic biogeographic studies, theoretical bases for recognizing tropical taxa with such disjunct distributions as Mexico and Madagascar, identification of taxa that may be most useful for testing vicariance models of Caribbean biogeography, and integrating the study of disjunct distributions in temperate regions of the northern hemisphere with those in the neo- and paleotropics.     

木兰科的分支分析

主要以形态学、解剖学、细胞学为依据,以德坚木属为外类群,用分支分析的方法探讨了木兰科属间的系统发育关系。有２３个分支单位,选取３２个性状,根据外类群比较原则和化石地层学资料,确定了性状的祖征和衍征。对数据矩阵的分支分析使用ＰＡＵＰ３．１．１和Ｈｅｎｎｉｇ ８６ ｖ．１．５分别在Ｍａｃｉｎｔｏｓｈ和ＩＢＭ机上运行,前者以启发法,后者以ＢＢ命令运算,经严格一致化处理,得到一致化分支图。结果表明：１）木     

Are lungfishes the sister group of tetrapods?

It is generally accepted that rhipaidistian crossopterygians are the closest relatives of tetrapods. Rosen, Forey, Gardiner & Patterson (1981) challenge this view and contend that lungfishes are the sister group of tetrapods. They present a detailed cladistic analysis and claim to identify a large number of synapomorphies shared by lungfishes and tetrapods but not by rhipidistians. Their analysis is faulty. Although Rosen et al. (1981) correctly emphasize that cladistic relationships must be based on shared derived characters, they often fail to take intragroup variation into account in postulating synapomorphies. They also use evidence inconsistently by attributing greater significance to similarities between lungfishes and tetrapods than to even more detailed similarities between rhipidistians and tetrapods. They misinterpret the skeletal pattern of the paired appendages. The many synapomorphies that they claim to have identified are either invalid, irrelevant, or are characters involving reduction or loss (which have a high probability of convergence). Consequently, they make an unconvincing case for a sister-group relationship between lungfishes and tetrapods. On the other hand, Rosen et al. (1981) do show that evidence for the orthodox view of rhipidistian-tetrapod relationships is not as strong as generally believed. The uncertain interrelationships among rhipidistians is a major problem. Tetrapod-fish relationships need to be re-examined by means of a properly conducted cladistic analysis.     

CHARACTER DIAGNOSIS, FOSSILS AND THE ORIGIN OF TETRAPODS

I. The traditional view of the origin of tetrapod vertebrates is that they are descendants of fossil osteolepiform fish, of which Eusthenopteron is best known. In recent years both that conclusion and the methodology by which it has been reached have been challenged by practitioners of cladistic analysis. Particularly a recent review by Rosen et al. (1981) claims that Dipnoi (lungfish) are the sister-group of the Tetrapoda, that Osteolepiformes is a non-taxon and that Eusthenopteron is more distant from tetrapods than are Dipnoi, coelacanths and probably the fossil Porolepiformes. We attempt to refute all these concludions by use of the same cladistic technique. 2. We accept that all the above-mentioned groups, together with some less well-known taxa, can be united as Sarcopterygii by means of shared derived (apomorph) characters. We also agree that Porolepiformes and Actinistia (coelacanths) can be characterized as valid taxa. The primitive and enigmatic fossil fish Powichthys is accepted as representing the plesiomorph sister-group of true porolepiforms. 3. Only two apomorph features, the course of the jaw adductor muscles and the position of incurrent and excurrent nostrils, appear to unite all the fish, living and fossil, currently regarded as Dipnoi. The characteristic tooth plates and the presence of petrodentine both exclude important primitive fossil forms. 4. Contrary to the opinion of Rosen et al., Osteolepiformes can be characterized — by the arrangement of bones forming the cheek plate, the presence of basal scutes to the fins and by the unjointed radials of the median fins. However, if these are true autapomorphies they exclude any osteolepiform from direct tetrapod ancestry. 5. Tetrapoda is a monophyletic group characterized by ten or more autapomorphies, including the bones of the cheek plate, a stapes and fenestra ovalis, and a series of characters of the appendicular skeleton. 6. Tetrapods have a true choana (internal nostril). We accept that the posterior (excurrent) nostril of Dipnoi is the homologue of the tetrapod choana. However, we assert that the posterior nostril of all bony fish is the homologue of the choana. This assertion would be refuted if any fish showed separate posterior nostril and choana. We reject the claim that this ‘three nostril condition’ occurred in porolepiforms and osteolepiforms. The evidence for a choana in porolepiforms is inadequate. Osteolepiforms had a true choana, characterized as in tetrapods by its relationship to the bones of the palate, but no third nostril. Dipnoans are not choanate. 7. Following cladistic practice, the relationship of the extant taxa is established first. Dipnoi are thus shown to be the living sister-group of tetrapods, but only on ‘soft anatomy’ characters unavailable in fossils. Coelacanths are the living sister-group of the taxon so formed. 8. The relationship of the fossil taxa to the extant sarcopterygians is then considered. The synapomorphy scheme proposed by Rosen et al. is discussed at length. Virtually all the characters they use to exclude close relationship of Eusthenopteron (and hence all osteolepiforms) to tetrapods, in favour of coelacanths and dipnoans, are invalid. 9. A series of synapomorphies uniting osteolepiforms and tetrapods is proposed, including a true choana (hence the taxon Choanata), the histology of the teeth, and a number of characters of the humerus. The recently discovered fossil Youngolepis, which lacks a choana, represents the sister-group of the Choanata, and is not uniquely close to Powichthys. The latter, as a porolepiform (s.l.) is a member of the sister-group to Choanata plus Youngolepis. 10. Our cladistic analysis suggests that all the extinct taxa considered are more closely related to tetrapods than are the Dipnoi. Moreover fossil evidence suggests that Dipnoi, considered as an extant taxon, may not even be the living sister-group of Tetrapoda. Early fossil dipnoans appear to have been marine fish without specific adaptations for air breathing. If so the apparent synapomorphies of Dipnoi and Tetrapoda may be homoplastic — the insistence on grouping extant taxa first would then have yielded an invalid inference.     

Phytogeny of the nematocerous families of Diptera (insecta)

The relationships of the nematocerous families of Diptera are cladistieally analysed using the parsimony programs PAUP and Hennig86. An extensive review, as well as a data matrix, is presented for 98 almost exclusively morphological characters (larva, 56; pupa, 6; adult, 36). Four infraorders are recognized, viz , Ptychopteromorpha, Culicomorpha, Blephariceromorpha, Bibionomorpha, and a clade containing the 'higher Nematocera' and Brachycera. Traditionally the family Nymphomyiidae or the infraorder Tipulomorpha (=Tipulidae, with or without Trichoceridae) are considered the most basal clade of the extant Diptera. On the basis of our cladistic analysis it is suggested that the Ptychopteromorpha-Culicomorpha clade is the sister-group of all other extant Diptera. We provide evidence that the Axymyiidae are part of a monophyletic Bibionomorpha. The latter infraorder is proposed as the sister-group of the higher Nematocera and Brachycera. We transfer the Tipulidae (Tipulomorpha) to the higher Nematocera, at a position next to Trichoceridae and near the Anisopodidae-Brachycera lineage. Previous hypotheses concerning nematocerous relationships are reviewed.     

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 Strepsiptera based on morphological data of the first instar larvae

This investigation was the first cladistic analysis using morphological data of first instar larvae of Strepsiptera. The analysis of representatives of nearly all known families of Strepsiptera supports the division of Strepsiptera into Mengenillidia and Stylopidia. Corioxenidae and Elenchidae are placed at the base of Stylopidia. Halictophagidae is the sister group to Xeninae + Myrmecolacidae + Stylopinae. Xeninae is placed as the sister group to Myrmecolacidae + Stylopinae. Stylopidae are paraphyletic. Thus, Xenidae stat. n. is re-established. A sister-group relationship between Myrmecolacidae and Elenchidae is not supported on characters of first instar larvae.     

Circularity and Independence in Phylogenetic Tests of Ecological Hypotheses

It has been asserted that in order to avoid circularity in phylogenetic tests of ecological hypotheses, one must exclude from the cladistic analysis any characters that might be correlated with that hypothesis. The argument assumes that selective correlation leads to lack of independence among characters and may thus bias the analysis. This argument conflates the idea of independence between the ecological hypothesis and the phylogeny with independence among characters used to construct the tree. We argue that adaptation or selection does not necessarily result in the non-independence of characters, and that characters for a cladistic analysis should be evaluated as homology statements rather than functional ones. As with any partitioning of data, character exclusion may lead to weaker phylogenetic hypotheses, and the practice of mapping characters onto a tree, rather than including them in the analysis, should be avoided. Examples from pollination biology are used to illustrate some of the theoretical and practical problems inherent in character exclusion.     

Tetrapod classification

The traditional palaeontological view that the mammals separated from the 'reptiles' before the origin of all other living amniotes is challenged. A radical alternative hypothesis, based on a character analysis of living tetrapods, is elaborated in which birds are considered the sister-group of mammals, crocodiles the sister-group of those two, chelonians the sister-group of those three, and squamates + Sphenodon the sister-group of those four. The living Amphibia are hypothesized to form a natural group and to be the sister-group of the Amniota. Further, I conclude that the Anapsida, Diapsida and Synapsida are paraphyletic or grade groups and no unique statements can be made about their structure.     

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.