Sauropod dinosaur phylogeny: critique and cladistic analysis

Sauropoda is among the most diverse and widespread dinosaurlineages, having attained a near‐global distribution by the MiddleJurassic that was built on throughout the Cretaceous. These giganticherbivores are characterized by numerous skeletal specializationsthat accrued over a 140 million‐year history. This fascinating evolutionaryhistory has fuelled interest for more than a century, yet aspectsof sauropod interrelationships remain unresolved. This paper presentsa lower‐level phylogenetic analysis of Sauropoda in two parts. First,the two most comprehensive analyses of Sauropoda are critiqued toidentify points of agreement and difference and to create a coreof character data for subsequent analyses. Second, a generic‐levelphylogenetic analysis of 234 characters in 27 sauropod taxa is presentedthat identifies well supported nodes as well as areas of poorerresolution. The analysis resolves six sauropod outgroups to Neosauropoda,which comprises the large‐nostrilled clade Macronaria and the peg‐toothedclade Diplodocoidea. Diplodocoidea includes Rebbachisauridae, Dicraeosauridae,and Diplodocidae, whose monophyly and interrelationships are supportedlargely by cranial and vertebral synapomorphies. In contrast, thearrangement of macronarians, particularly those of titanosaurs,are based on a preponderance of appendicular synapomorphies. The purportedChinese clade ‘Euhelopodidae’ is shown to comprisea polyphyletic array of basal sauropods and neosauropods. The synapomorphiessupporting this topology allow more specific determination for themore than 50 fragmentary sauropod taxa not included in this analysis.Their distribution and phylogenetic affinities underscore the diversityof Titanosauria and the paucity of Late Triassic and Early Jurassicgenera. The diversification of Titanosauria during the Cretaceousand origin of the sauropod body plan duringthe Late Triassic remain frontiers for future studies. © 2002The Linnean Society of London, Zoological Journal of the LinneanSociety, 2002, 136 , 217?276.     

Palaeomorphology: fossils and the inference of cladistic relationships

Edgecombe, G.D. 2010. Palaeomorphology: fossils and the inference of cladistic relationships. —Acta Zoologica (Stockholm) 91 : 72–80 Twenty years have passed since it was empirically demonstrated that inclusion of extinct taxa could overturn a phylogenetic hypothesis formulated upon extant taxa alone, challenging Colin Patterson’s bold conjecture that this phenomenon ‘may be non‐existent’. Suppositions and misconceptions about missing data, often couched in terms of ‘wildcard taxa’ and ‘the missing data problem’, continue to cloud the literature on the topic of fossils and phylogenetics. Comparisons of real data sets show that no a priori (or indeed a posteriori) decisions can be made about amounts of missing data and most properties of cladograms, and both simulated and real data sets demonstrate that even highly incomplete taxa can impact on relationships. The exclusion of fossils from phylogenetic analyses is neither theoretically nor empirically defensible.     

Primary classification and phylogeny of the Polemoniaceae, with comments on molecular cladistics

The system of classification of the Polemoniaceae currently in use was published by Grant in 1959. Much new evidence concerning relationships in the family has been obtained by numerous workers since 1959, and the old system is in need of revision. A revised system down to the genus level, based on conventional and unconventional characters, including molecular evidence, is presented here. Nineteen genera are grouped into eight tribes and two subfamilies. Three new tribes are described: Acanthogilieae, Loeselieae, and Leptodactyloneae. Several genera are transferred to new groups. The phylogeny of the family is discussed in the light of both the older and new evidence. The approach used in constructing both the 1959 and new systems is that of evolutionary systematics. Two recent (1996, 1997) family-wide surveys of cpDNA and rDNA use cladistic methods of analysis to arrive at sets of major groups. Some of this molecular evidence has been adopted for the present revised system. However, much incongruence still exists between the new sets of clades, on the one hand, and the present revised system or the still-viable parts of the 1959 system on the other hand. The incongruences call for an examination and comparison of the contrasting methods of evolutionary systematics and molecular cladistics. A fundamental flaw in the 1996 and 1997 treatments is the attempt to classify plants on the basis of single-gene gene trees.     

Calcite and aragonite distributions in the skeletons of bimineralic bryozoans as revealed by Raman spectroscopy

Abstract. Bryozoans are among a diverse range of invertebrates capable of secreting calcium carbonate skeletons. Relatively little is known about biomineralization in bryozoans, despite the importance of understanding biomineralization processes for nanotechnology and the threats imposed by ocean acidification on organisms having calcareous skeletons. Ten species of cheilostome bryozoans that are reported to have bimineralic skeletons of calcite and aragonite are studied here using Raman spectroscopy. This technique allowed identification of the two mineral phases at submicron spatial resolution, allowing the distributions of calcite and aragonite within bryozoan skeletons to be determined with unprecedented precision. Confirming previous findings based on the use of chemical stains, most of the bimineralic species analyzed exhibited a calcitic skeletal framework, composed of basal, vertical, and inner frontal walls, having aragonite deposited subsequently onto the outer surfaces of the frontal walls. In one species ( Odontionella cyclops ), aragonite formed the superstructure above the autozooids, and in two others, traces of aragonite were detected on the undersides of the frontal shields. Using Raman spectroscopy, it was possible for the first time to determine the mineralogy of small-scale structures, including orificial rims, condyles and hinge teeth, avicularian pivotal bars and rostra, and ascopore rims and sieve plates. Even when surrounded by aragonitic frontal shields, these structures were found typically to be calcitic, the two exceptions being the aragonitic avicularia of Stylopoma inchoans and O. cyclops . Unexpectedly, the first-formed part of the basal wall at the distalmost growing edge of Pentapora foliacea was found to consist mainly of aragonite. This may point to a precursory phase of biomineralization comparable with the unusual mineralogies identified previously in the earliest-formed skeletons of members of some other invertebrate phyla.     

Evolution of larval size in cyclostome bryozoans

Cyclostomes are the only order of stenolaemate bryozoans living today. The non-feeding larvae of modern cyclostomes metamorphose on settlement to produce a calcified dome-shaped protoecium. Protoecial diameter provides a proxy for larval size. The sparse data available on living cyclostomes suggests that protoecial diameter is about one-and-a-half times greater than larval width. Here we use protoecial diameter to estimate larval sizes in fossil and Recent cyclostome species. A total of 233 protoecia were measured, 143 from Recent cyclostomes and 90 from fossil cyclostomes, of which 84 came from the Jurassic. Protoecial diameter ranged from 82.5 to 690 μm, with 89% of protoecia having diameters between 100 and 300 μm. A comparison of 30 Jurassic with 51 Recent taxa of tubuliporine cyclostomes showed a significant difference in size frequency. Although the Recent taxa have a larger size range (83–465 μm) than the Jurassic taxa (125–249 μm), Recent species have a lower mode (125–150 μm) than the Jurassic species (175–200 μm). Most Jurassic cyclostomes may therefore have had larger larvae than their extant relatives. Reduction in larval size may be a component of the previously hypothesized reduction in overall body size resulting from competitive displacement by cheilostome bryozoans.     

Higher-order phylogeny of modern birds (Theropoda, Aves: Neornithes) based on comparative anatomy. II. Analysis and discussion

In recent years, avian systematics has been characterized by a diminished reliance on morphological cladistics of modern taxa, intensive palaeornithogical research stimulated by new discoveries and an inundation by analyses based on DNA sequences. Unfortunately, in contrast to significant insights into basal origins, the broad picture of neornithine phylogeny remains largely unresolved. Morphological studies have emphasized characters of use in palaeontological contexts. Molecular studies, following disillusionment with the pioneering, but non-cladistic, work of Sibley and Ahlquist, have differed markedly from each other and from morphological works in both methods and findings. Consequently, at the turn of the millennium, points of robust agreement among schools concerning higher-order neornithine phylogeny have been limited to the two basalmost and several mid-level, primary groups. This paper describes a phylogenetic (cladistic) analysis of 150 taxa of Neornithes, including exemplars from all non-passeriform families, and subordinal representatives of Passeriformes. Thirty-five outgroup taxa encompassing Crocodylia, predominately theropod Dinosauria, and selected Mesozoic birds were used to root the trees. Based on study of specimens and the literature, 2954 morphological characters were defined; these characters have been described in a companion work, approximately one-third of which were multistate (i.e. comprised at least three states), and states within more than one-half of these multistate characters were ordered for analysis. Complete heuristic searches using 10 000 random-addition replicates recovered a total solution set of 97 well-resolved, most-parsimonious trees (MPTs). The set of MPTs was confirmed by an expanded heuristic search based on 10 000 random-addition replicates and a full ratchet-augmented exploration to ascertain global optima. A strict consensus tree of MPTs included only six trichotomies, i.e. nodes differing topologically among MPTs. Bootstrapping (based on 10 000 replicates) percentages and ratchet-minimized support (Bremer) indices indicated most nodes to be robust. Several fossil Neornithes (e.g. Dinornithiformes, Aepyornithiformes) were placed within the ingroup a posteriori either through unconstrained, heursitic searches based on the complete matrix augmented by these taxa separately or using backbone-constraints. Analysis confirmed the topology among outgroup Theropoda and achieved robust resolution at virtually all levels of the Neornithes. Findings included monophyly of the palaeognathous birds, comprising the sister taxa Tinamiformes and ratites, respectively, and the Anseriformes and Galliformes as monophyletic sister-groups, together forming the sister-group to other Neornithes exclusive of the Palaeognathae (Neoaves). Noteworthy inferences include: (i) the sister-group to remaining Neoaves comprises a diversity of marine and wading birds; (ii) Podicipedidae are the sister-group of Gaviidae, and not closely related to the Phoenicopteridae, as recently suggested; (iii) the traditional Pelecaniformes, including the shoebill (Balaeniceps rex) as sister-taxon to other members, are monophyletic; (iv) traditional Ciconiiformes are monophyletic; (v) Strigiformes and Falconiformes are sister-groups; (vi) Cathartidae is the sister-group of the remaining Falconiformes; (vii) Ralliformes (Rallidae and Heliornithidae) are the sister-group to the monophyletic Charadriiformes, with the traditionally composed Gruiformes and Turniciformes (Turnicidae and Mesitornithidae) sequentially paraphyletic to the entire foregoing clade; (viii) Opisthocomus hoazin is the sister-taxon to the Cuculiformes (including the Musophagidae); (ix) traditional Caprimulgiformes are monophyletic and the sister-group of the Apodiformes; (x) Trogoniformes are the sister-group of Coliiformes; (xi) Coraciiformes, Piciformes and Passeriformes are mutually monophyletic and closely related; and (xii) the Galbulae are retained within the Piciformes. Unresolved portions of the Neornithes (nodes having more than one most-parsimonious solution) comprised three parts of the tree: (a) several interfamilial nodes within the Charadriiformes; (b) a trichotomy comprising the (i) Psittaciformes, (ii) Columbiformes and (iii) Trogonomorphae (Trogoniformes, Coliiformes) + Passerimorphae (Coraciiformes, Piciformes, Passeriformes); and (c) a trichotomy comprising the Coraciiformes, Piciformes and Passeriformes. The remaining polytomies were among outgroups, although several of the highest-order nodes were only marginally supported; however, the majority of nodes were resolved and met or surpassed conventional standards of support. Quantitative comparisons with alternative hypotheses, examination of highly supportive and diagnostic characters for higher taxa, correspondences with prior studies, complementarity and philosophical differences with palaeontological phylogenetics, promises and challenges of palaeogeography and calibration of evolutionary rates of birds, and classes of promising evidence and future directions of study are reviewed. Homology, as applied to avian examples of apparent homologues, is considered in terms of recent theory, and a revised annotated classification of higher-order taxa of Neornithes and other closely related Theropoda is proposed. (c) 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 149, 1-95.     

Description and phylogeny of a new Neotropical genus of Acalyptini (Coleoptera: Curculionidae: Curculioninae) associated with the staminodes of Cyclanthaceae

The weevil genus Azotoctla gen. nov. (Coleoptera: Curculionidae: Curculioninae: Acalyptini Thomson), is described to accommodate the following 15 new Neotropical species: Azotoctla aecuatorialis sp. nov. (Ecuador), Azotoctla anerunca sp. nov. (Ecuador), Azotoctla angustacra sp. nov. (Ecuador), Azotoctla curvirostra sp. nov. (Peru), Azotoctla dasygastra sp. nov. (Costa Rica and Honduras), Azotoctla femorata sp. nov. (Colombia, Costa Rica, Ecuador and Panama), Azotoctla gomezi sp. nov. (Colombia, Costa Rica and Panama), Azotoctla gottsbergeri sp. nov. (Brazil), Azotoctla clemmyssa sp. nov. (Colombia), Azotoctla melolauta sp. nov. (Colombia), Azotoctla migueli sp. nov. (Colombia), Azotoctla nana sp. nov. (Panama), Azotoctla punctata sp. nov. (Costa Rica), Azotoctla tibiatra sp. nov. (Belize), and Azotoctla tuberquiai sp. nov. (Colombia). Azotoctla is placed in the tribe Acalyptini, subtribe Staminodeina Franz, thus representing the sister taxon of Staminodeus Franz. The monophyly of Azotoctla is supported by the following inferred traits: a noncarinate rostrum that is tumescent above the antennal insertion in males; equilaterally subtriangular hemisternites of the male sternum 8; paired, longitudinal, laterally positioned sclerites of the aedeagus; and a bifurcate lamina of the female sternum 8, which bears explanate, diverging furcal arms. A key to the species of Azotoctla is provided; and the salient features of each species are illustrated and presented along with distributional and natural history data. A morphological cladistic analysis of 23 terminal species (eight outgroup, 15 ingroup) and 33 characters yielded a single most parsimonious cladogram (length = 75 steps, consistency index = 52, retention index = 77), with the ingroup topology ((A. aecuatorialis, (A. anerunca, A. gottsbergeri)), (A. punctata, ((A. angustacra, A. nana), (A. tibiatra, (A. clemmyssa, (A. curvirostra, A. femorata)), (A. melolauta, ((A. gomezi, A. migueli), (A. dasygastra, A. tuberquiai))))))). Species of Azotoctla are reproductively associated with the ephemeral staminodes of different members of the Neotropical monocot family Cyclanthaceae; most commonly with the widespread genus Carludovica Ruiz & Pavón. The interspecific homogeneity in external morphology, coupled with marked differences in genital traits and an apparent absence of narrow geographical ranges mediated by either host plants and/or biogeographical factors, jointly suggest that the diversification of Azotoctla is a relatively recent phenomenon and driven strongly by sexual selection. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 559–623.     

High-level phylogeny of early Tertiary rodents: dental evidence

Major crown‐groups of rodents were well established in the early Tertiary, and fossils provide an invaluable window into their evolutionary history. The main focus of this project was to perform a cladistic assessment of the dental evidence for early Tertiary rodent cladogenesis – the masticatory apparatus and teeth are the most frequently preserved anatomical features in the fossil record. We focused on groups that existed in a period corresponding to their early history, combining fossils belonging to extinct lineages and to stem‐groups leading to modern lineages. While the monophyly of some groups is not systematically explored, our results have important implications for high‐level rodent relationships and systematics. These results are consistent with those of recent molecular phylogenies and reliably congruent with the stratigraphic record, thus enhancing the pertinence of dental characters for phylogenetic inference. Our approach provides evidence of a fundamental dichotomy in early rodent history. Two major clades have been identified: (1) the earliest ‘ctenodactyloid’ (Ctenodactylidae, Chapattimyidae, Yuomyidae, Diatomyidae) and hystricognathous (Tsaganomyidae, Baluchimyinae, ‘phiomorphs’, ‘caviomorphs’) rodents, and (2) the earliest ‘ischyromyoid’ rodents with their closest relatives (Muroidea + Dipodoidea + Geomyoidea + Anomaluroidea + Castoroidea + Sciuravidae + Gliroidea, and Sciuroidea + Aplodontoidea + Theridomorpha). This topology has led us to endorse Ctenohystrica as the first clade and propose a new taxon, Ischyromyiformes, for the second. Although minimized in our working hypothesis, the homoplasy in dental characters remains significant. However, a number of homoplasic characters reveal structuring in their internal distribution, allowing us to discern evolutionary morphological patterns, notably the pentalophodonty of molars, zygomasseteric complex and incisor enamel microstructure. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 142 , 105–134.     

A phylogenetic analysis of basal Anseriformes, the fossil Presbyornis, and the interordinal relationships of waterfowl

A phylogenetic analysis of 123 morphological characters of basal waterfowl (Aves: Anseriformes) and other selected avian orders confirmed that the screamers (Anhimae: Anhitn-idae) are the sister-group of other waterfowl (Anseres), and that the magpie goose (Anseranatidae: Anseranas semipalmata) is the sister group of other modern waterfowl exclusive of screamers (Anatidae sensu stricto). The analysis also supports the traditional hypothesis of the gallinaceous birds (Galliformes) as the sister group of the Anseriformes. Presbyornis, a fossil from the early Eocene of Wyoming and averred by Olson & Feduccia as showing that the Anseriformes were derived from shorebirds (Charadriiformes), was found to represent the sister group of the Anatidae. Associated hypotheses by Olson & Feduccia concerning the implications of Presbyornis for the phylogenetic relationships of flamingos (Phoenicopteriformes), the position of the Anhimidae within the waterfowl, relationships among modern Anatidae, and a plausible evolutionary scenario for waterfowl also are rejected. Analyses revealed that cranial characters were critical to the establishment of the Galliformes as the sister group of the Anseriformes; exclusion of the Anhimidae, especially in combination with Anseranas, also undermined the support for this inference. Placement of Presbyornis as the sister group of the Anatidae casts doubt on the role suggested by Feduccia of ‘transitional shorebirds' in the origin of modern avian orders, and calls into question the concept of ‘fossil mosaics’. The phylogenetic hypothesis is used to reconstruct an evolutionary scenario for selected ecomorphological characters in the galliform-anseriform transition, to predict the most parsimonious states of these characters for Presbyornis, and to propose a phylogenetic classification of the higher-order taxa of waterfowl. This re-examination of Presbyornis also is used to exemplify the fundamental methodological shortcomings of the intuitive approach to the reconstruction of phylogenetic relationships.     

Diagnosis and phylogeny of the new world streptocephalidae (Branchiopoda: Anostraca)

We present an updated diagnosis of 13Streptocephalus species of North America. Three new species are included. A key to the species is provided.The phylogeny of the group is discussed on the basis of (1) a systematic approach (Maeda-Martinezet al., 1995; this volume), which considers the entire distal antennal outgrowth, the frontal appendage, and the morphology of the ovaries as essential in defining different genetic lineages or species-groups, and (2) a cladistic analysis. We suggest that of nine monophyletic groups, three are represented in both the Old and New World. Thus, contrary to former disparsalist hypotheses, we argue that the New World species represent relict forms of ancestral groups fragmented by continental drift (vicariance model).     

What does morphology tell us about orchid relationships?—a cladistic analysis

A cladistic analysis of Orchidaceae was undertaken for 98 genera using 71 morphological apomorphies based on a reconsideration of previous character analyses and newly discovered variation. The equally weighted analysis found 60 000 most parsimonious trees with low consistency (CI = 0.29) but high retention (RI = 0.83). The strict consensus reveals a significant amount of structure, and most traditionally recognized subfamilies are supported as monophyletic, including the Apostasioideae, Cypripedioideae, Spiranthoideae, and Epidendroideae. Orchidoideae in the broad sense are paraphyletic, giving rise to spiranthoids. Vanilloids are sister to epidendroids, although exhibiting several states otherwise found only in clearly basal groups, such as Apostasioideae. The nonvandoid epidendroids are poorly resolved, due to a high degree of homoplasy. The vandoids appear to be monophyletic, contrary to recent molecular evidence, possibly due to repeated parallel development of the vandoid character suite. The importance of vegetative characters as evidence putatively independent from floral features is demonstrated in the placement of Tropidia. Implied weighting analysis of these data resulted in similar patterns at high levels, although the Orchidoideae and Spiranthoideae may each be monophyletic and the nonvandoid epidendroids are more resolved. The high degree of structure implied in previous orchid classifications must be reconsidered, given the poor resolution at lower levels in the present trees.     

Tachyoryctes makooka (Tachyoryctini,Spalacidae, Rodentia) and its bearing on the phylogeny of the Tachyoryctini

Abstract: The Rhizomyinae is a subfamily of myomorph rodents within the family Spalacidae. It is subdivided into two tribes: the Asian Rhizomyini and the Tachyoryctini. Even though the origin of the Tachyoryctini is to be found in Asia, they are nowadays restricted to Africa. African Tachyoryctini are known from the Late Miocene and include a single genus with five species: the recently discovered Tachyoryctes makooka, which is described in detail in this work, T. pliocaenicus, T. konjiti and the two extant T. splendens and T. macrocephalus. Their closest Asian counterparts are the Late Miocene Protachyoryctes and Eicooryctes. A cladistic analysis involving all the above‐mentioned taxa was carried out. Protachyoryctes tatroti turned out to be the most basal species of the ingroup followed by the Ethiopian T. makooka. Both taxa show some primitive traits like the protosinus on the first upper molars, short but distinct mesolophids on the lower molars and the presence of the mure on the cheek teeth. T. pliocaenicus and the most derived Tachyoryctini share the synapomorphic reduction or loss of these characters. The increase in hypsodonty evidenced in this lineage is correlated with the transition from a humid to a drier climate that started at the beginning of the Pliocene.     

Phylogeny, classification, and biogeography of the cycloteline Therevinae (Insecta: Diptera: Thereavidae)

Twenty-one members of the Laurasian group of Therevinae (Diptera: Therevidae) are compared using 65 adult morphological characters. Cladistic analysis using parsimony on the 17 ingroup and 4 outgroup taxa provides a well-supported hypothesis of relationships among taxa within the Gyclotelini, tribe nov. The Cyclotelini is a monophyletic assemblage of mostly New World genera, including Anolinga , gen. nov. , Breviperna Irwin, Coleiana , gen. nov. , Crebraseta , gen. nov. , Cyclotelus Walker, Mesonana , gen.nov. , and Ozodiceromyia Bigot. In addition, three Old World genera, Ammothereva Lyneborg, Bugulaverpa , gen. nov. , and Procyclotelus Nagatomi & Lyneborg, are included in the tribe. These ten genera are divided into two monophyletic genus-groups, the Brevipema-group and the Cyclotelus-group. Keys are provided for the genera of Cyclotelini. The tribe, the two informal genus-groups, and all genera are diagnosed; five new genera and six new species are proposed. The biogeographical histories of the genera are discussed in terms of their cladistic relationships using methods of cladistic biogeography. Two major vicariant events account for the current distribution of the tribe. The first relates to the Beringian land bridge connecting western North America and eastern Asia. Second, New World cyclotelines were profoundly affected by the Early Eocene breakup of the archipelagic bridge between North and South America, and the distributions support the hypotheses favouring the continental origin of the Greater Antilles.     

Weintrauboa, a new genus of pimoid spiders from Japan and adjacent islands, with comments on the monophyly and diagnosis of the family Pimoidae and the genus Pimoa (Araneoidea, Araneae)

The spider genus Weintrauboa new genus (Araneae, Pimoidae) is described to place two species of pimoids from Japan and adjacent islands that were formerly classified in the linyphiid genus Labulla . Weintrauboa contortipes (Karsch) new comb., the type species, and W. chikunii (Oi) new comb. are redescribed. Parsimony analysis of morphological characters provides robust support for the monophyly of the genus Weintrauboa and corroborates the monophyly of Pimoa , Pimoidae, and the clade Linyphiidae plus Pimoidae. New diagnoses for Pimoa and Pimoidae are provided.  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society , 2003, 139 , 261–281     

Skull anatomy of the Oligocene toothed mysticete Aetioceus weltoni (Mammalia; Cetacea): implications for mysticete evolution and functional anatomy

Toothed mysticetes of the family Aetiocetidae from Oligocene rocks of the North Pacific play a key role in interpretations of cetacean evolution because they are transitional in grade between dorudontine archaeocetes and edentulous mysticetes. The holotype skull of Aetiocetus weltoni from the late Oligocene (28–24 Ma) of Oregon, USA, has been further prepared, revealing additional morphological features of the basicranium, rostrum and dentary that have important implications for mysticete evolution and functional anatomy. The palate of Aetiocetus weltoni preserves diminutive lateral palatal foramina and associated delicate sulci which appear to be homologous with the prominent palatal foramina and sulci that occur along the lateral portion of the palate in extant mysticetes. In modern baleen whales these foramina allow passage of branches of the superior alveolar artery, which supplies blood to the epithelia of the developing baleen racks. As homologous structures, the lateral palatal foramina of A. weltoni suggest that baleen was present in this Oligocene toothed mysticete. Cladistic analysis of 46 cranial and dental characters supports monophyly of the Aetiocetidae, with toothed mysticetes Janjucetus and Mammalodon positioned as successive sister taxa. Morawanacetus is the earliest diverging aetiocetid with Chonecetus as sister taxon to Aetiocetus species. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 308–352.     

The skull of Monolophosaurus jiangi (Dinosauria: Theropoda) and its implications for early theropod phylogeny and evolution

The Middle Jurassic was a critical time in the evolution of theropod dinosaurs, highlighted by the origination and initial radiation of the large‐bodied and morphologically diverse Tetanurae. Middle Jurassic tetanurans are rare, but have been described from Europe, South America and China. In particular, China has yielded a number of potential basal tetanurans, but these have received little detailed treatment in the literature. Chief among these is Monolophosaurus jiangi, known from a single skeleton that includes a nearly complete and well‐preserved skull characterized by a bizarre cranial crest. Here, we redescribe the skull of Monolophosaurus, which is one of the most complete basal tetanuran skulls known and the only quality source of cranial data for Middle Jurassic Chinese theropods. The cranial crest is atomized into a number of autapomorphic features and several characters confirm the tetanuran affinities of Monolophosaurus. However, several features suggest a basal position within Tetanurae, which contrasts with most published cladistic analyses, which place Monolophosaurus within the more derived Allosauroidea. Cranial characters previously used to diagnose Allosauroidea are reviewed and most are found to have a much wider distribution among Theropoda, eroding an allosauroid position for Monolophosaurus and questioning allosauroid monophyly. The use of phylogenetic characters relating to theropod cranial crests is discussed and a protocol for future use is given. The systematic position of Guanlong wucaii is reviewed, and a basal tyrannosauroid affinity is upheld contrary to one suggestion of a close relationship between this taxon and Monolophosaurus. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 573–607.     

Snake phylogeny based on osteology,soft anatomy and ecology

Relationships between the major lineages of snakes are assessed based on a phylogenetic analysis of the most extensive phenotypic data set to date (212 osteological, 48 soft anatomical, and three ecological characters). The marine, limbed Cretaceous snakes Pachyrhachis and Haasiophis emerge as the most primitive snakes: characters proposed to unite them with advanced snakes (macrostomatans) are based on unlikely interpretations of contentious elements or are highly variable within snakes. Other basal snakes include madtsoiids and Dinilysia--both large, presumably non-burrowing forms. The inferred relationships within extant snakes are broadly similar to currently accepted views, with scolecophidians (blindsnakes) being the most basal living forms, followed by anilioids (pipesnakes), booids and booid-like groups, acrochordids (filesnakes), and finally colubroids. Important new conclusions include strong support for the monophyly of large constricting snakes (erycines, boines. pythonines), and moderate support for the non-monophyly of the trophidophiids' (dwarf boas). These phylogenetic results are obtained whether varanoid lizards, or amphisbaenians and dibamids, are assumed to be the nearest relatives (outgroups) of snakes, and whether multistate characters are treated as ordered or unordered. Identification of large marine forms, and large surface-active terrestrial forms, as the most primitive snakes contradicts with the widespread view that snakes arose via minute, burrowing ancestors. Furthermore, these basal fossil snakes all have long flexible jaw elements adapted for ingesting large prey ('macrostomy'), suggesting that large gape was primitive for snakes and secondarily reduced in the most basal living foms (scolecophidians and anilioids) in connection with burrowing. This challenges the widespread view that snake evolution has involved progressive, directional elaboration of the jaw apparatus to feed on larger prey.     

Towards a phylogeny of the flesh flies (Diptera: Sarcophagidae): morphology and phylogenetic implications of the acrophallus in the subfamily Sarcophaginae

The morphology of the acrophallus, the distal portion of the male phallus carrying the phallotreme, was studied in 72 exemplar species representing 56 genera and subgenera of the flesh fly subfamily Sarcophaginae. For 42 of those species, scanning electron microscopy was used to clarify the phallic morphology. Terms used to describe the male genitalia were updated based on new interpretations of homology. Male genitalic characters, combined with other morphological characters of adult males and females and of larvae, were used to construct a phylogeny. The monophyly of the subfamily was supported, and some generic‐level sister‐group relationships proposed in the literature, but without previous cladistic analyses, were also supported. The genus Blaesoxipha Loew, as currently recognized, was not monophyletic in our analysis. The genus Helicobia Coquillett is synonymized with Sarcophaga Meigen syn. nov. and treated as a subgenus of the latter. The Sarcophaga subgenera Neobellieria Blanchard and Mehria Enderlein were not monophyletic. Many of the clades in the analysis were supported primarily or exclusively by male genitalic character states, highlighting the importance of the male genitalia as a source of morphological characters for sarcophagine phylogeny. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 740–778.