Basal titanosauriform (Dinosauria, Sauropoda) teeth from the Lower Cretaceous Yixian Formation of Liaoning Province, China

The Yixian Formation of Liaoning Province, People's Republic of China has yielded a diverse fauna of non-avian dinosaurs, but is dominated by small-bodied taxa. Here, we describe a series of isolated teeth from the Lujiatun Beds of the formation that are referable to a basal titanosauriform sauropod. Some of the teeth possess a distinctive circular boss on the lingual surface, which suggests that they are referable to cf. Euhelopus sp. This identification provides some additional support for biostratigraphical correlations between the Jehol Group and the Mengyin Formation of Shandong Province that suggest an Early Cretaceous age for the latter unit. Moreover, the titanosauriform affinities of the teeth provide further evidence for the dominance of this sauropod clade in eastern Asia during the Cretaceous.     

A new nothrotheriid xenarthran from the early Pliocene of Pomata‐Ayte (Bolivia): new insights into the caniniform–molariform transition in sloths

Tardigrade xenarthrans are today represented only by the two tree sloth genera Bradypus and Choloepus, which inhabit the Neotropical rainforests and are characterized by their slowness and suspensory locomotion. Sloths have been recognized in South America since the early Oligocene. This monophyletic group is represented by five clades traditionally recognized as families: Bradypodidae, Megalonychidae, Mylodontidae (?), Megatheriidae (?) and Nothrotheriidae (?). A new nothrotheriid ground sloth represented by a dentary and several postcranial elements, Aymaratherium jeani gen. nov. , sp. nov. , from the early Pliocene locality of Pomata‐Ayte (Bolivia) is reported. This small‐ to medium‐sized species is characterized especially by its dentition and several postcranial features. It exhibits several convergences with the ‘aquatic’ nothrotheriid sloth Thalassocnus and the giant megatheriid ground sloth Megatherium (M.) americanum, and is interpreted as a selective feeder, with good pronation and supination movements. The tricuspid caniniform teeth of Aymaratherium may represent a transitional stage between the caniniform anterior teeth of basal megatherioids and basal nothrotheriids (1/1C‐4/3M as in Hapalops or Mionothropus) and the molariform anterior teeth of megatheriids (5/4M, e.g. Megatherium). To highlight the phylogenetic position of this new taxon among nothrotheriid sloths, we performed a cladistic assessment of the available dental and postcranial evidence. Our results, derived from a TNT treatment of a data matrix largely based on a published phylogenetic data set, indicate that Aymaratherium is either sister taxon to Mionothropus or sister to the clade Nothrotheriini within Nothrotheriinae. They further support the monophyly of both the Nothrotheriinae and the Nothrotheriini, as suggested previously by several authors.     

The anatomy of the basal ornithischian dinosaur Eocursor parvus from the lower Elliot Formation (Late Triassic) of South Africa

Ornithischia is a morphologically and taxonomically diverse clade of dinosaurs that originated during the Late Triassic and were the dominant large‐bodied herbivores in many Cretaceous ecosystems. The early evolution of ornithischian dinosaurs is poorly understood, as a result in part of a paucity of fossil specimens, particularly during the Triassic. The most complete Triassic ornithischian dinosaur yet discovered is Eocursor parvus from the lower Elliot Formation (Late Triassic: Norian–Rhaetian) of Free State, South Africa, represented by a partial skull and relatively complete postcranial skeleton. Here, the anatomy of Eocursor is described in detail for the first time, and detailed comparisons are provided to other basal ornithischian taxa. Eocursor is a small‐bodied taxon (approximately 1 m in length) that possesses a plesiomorphic dentition consisting of unworn leaf‐shaped crowns, a proportionally large manus with similarities to heterodontosaurids, a pelvis that contains an intriguing mix of plesiomorphic and derived character states, and elongate distal hindlimbs suggesting well‐developed cursorial ability. The ontogenetic status of the holotype material is uncertain. Eocursor may represent the sister taxon to Genasauria, the clade that includes most of ornithischian diversity, although this phylogenetic position is partially dependent upon the uncertain phylogenetic position of the enigmatic and controversial clade Heterodontosauridae. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 648–684.     

The phylogeny of Sericini and their position within the Scarabaeidae based on morphological characters (Coleoptera: Scarabaeidae)

Abstract. To reconstruct the phylogeny of the Sericini and their systematic position among the scarabaeid beetles, cladistic analyses were performed using 107 morphological characters from the adults and larvae of forty‐nine extant scarabaeid genera. Taxa represent most ‘traditional’ subfamilies of coprophagous and phytophagous Scarabaeidae, with emphasis on the Sericini and other melolonthine lineages. Several poorly studied exoskeletal features have been examined, including the elytral base, posterior wing venation, mouth parts, endosternites, coxal articulation, and genitalia. The results of the analysis strongly support the monophyly of the ‘orphnine group’ + ‘melolonthine group’ including phytophagous scarabs such as Dynastinae, Hopliinae, Melolonthinae, Rutelinae, and Cetoniinae. This clade was identified as the sister group to the ‘dung beetle line’ represented by Aphodius + Copris. The ‘melolonthine group’ is comprised in the strict consensus tree by two major clades and two minor lineages, with the included taxa of Euchirinae, Rutelinae, and Dynastinae nested together in one of the major clades (‘melolonthine group I’). Melolonthini, Cetoniinae, and Rutelinae are strongly supported, whereas Melolonthinae and Pachydemini appear to be paraphyletic. Sericini + Ablaberini were identified to be sister taxa nested within the second major melolonthine clade (‘melolonthine group II’). As this clade is distributed primarily in the southern continents, one could assume that Sericini + Ablaberini are derived from a southern lineage. Plausibly, ancestors of Sericini + Ablaberini and Athlia were separated by a vicariance event, such as the separation of the African plate from the rest of Gondwana, whereas Sericini and Ablaberini probably diversified during the early Tertiary, with dispersal of some basal Sericini to South America.     

A new basal sauropodiform from South Africa and the phylogenetic relationships of basal sauropodomorphs

We present a new medium‐sized basal sauropodomorph, S efapanosaurus zastronensis gen. et sp. nov. , from the Upper Triassic?Lower Jurassic Elliot Formation of South Africa. It is represented by parts of the postcranial skeleton of at least four individuals, including: cervical, dorsal, sacral and caudal vertebrae, most of the forelimb, and part of the hindlimb. Sefapanosaurus bears several autapomorphies of the astragalus, and referred material also shows autapomorphic features. The inclusion of Sefapanosaurus in a phylogenetic analysis places it within the group of sauropodomorphs more closely related to sauropods than to Massospondylus (i.e. Sauropodiformes), increasing the currently known diversity of the so‐called ‘transitional forms’ leading to Sauropoda. Character optimization revealed the presence of several features that are common for taxa placed within the transitional branches basal to Sauropoda. Sefapanosaurus, together with other transitional sauropodomorphs reported during the last decade, highlights the importance of Gondwanan taxa for understanding the palaeobiodiversity, global distribution, and macroevolutionary changes in the group related to the rise of sauropods. © 2015 The Linnean Society of London     

Global phylogeny of Hadrosauridae (Dinosauria: Ornithopoda) using parsimony and Bayesian methods

The late Cretaceous hadrosaurids were the most specialized and diverse clade of ornithopod dinosaurs. Parsimony and Bayesian methods were implemented to elucidate the phylogenetic relationships of all hadrosaurid species. Traditional and geometric morphometrics were applied to discover patterns of variation containing phylogenetic information. In total, 286 phylogenetically informative characters (196 cranial and 90 postcranial) were defined and documented: the most extensive character data set ever constructed for hadrosaurid dinosaurs. Of these, 136 characters were used for the first time in phylogenetic analysis of these ornithopods, and 93 were modified from those of other authors. Parsimony and the Bayesian analysis (using the Mk model without the gamma parameter) confirmed the split of hadrosaurids into Saurolophinae and Lambeosaurinae. Saurolophines included a major clade composed of the Prosaurolophus–Saurolophus and the Kritosaurus–Gryposaurus–Secernosaurus subclades. Edmontosaurus and Shantungosaurus were recovered outside the major clade of saurolophines. The Brachylophosaurus clade was recovered as the most basal clade of saurolophines in the parsimony analysis, whereas following the Bayesian analysis it was recovered as the sister clade to the Kritosaurus–Gryposaurus–Secernosaurus clade. These two analyses resulted in a Lambeosaurinae composed of a succession of Eurasian sister taxa to two major clades: the Parasaurolophus clade and the Hypacrosaurs altispinus–Corythosaurus clade. In contrast, the Bayesian analysis using the Mk model with the gamma parameter included, resulted in an unbalanced hadrosauroid tree, with a paraphyletic Saurolophinae, and with the Prosaurolophus clade, Edmontosaurus, and Shantungosaurus as successively closer sister taxa to Lambeosaurinae. Based on the strict reduced consensus tree derived from the parsimony analysis, Hadrosauridae was redefined as the clade stemming from the most recent common ancestor of Hadrosaurus foulkii and Parasaurolophus walkeri. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 159 , 435–502.     

Osteology and relationships of Thaiichthys nov. gen.: a Ginglymodi from the Late Jurassic – Early Cretaceous of Thailand

Abstract: The osteology of Thaiichthys buddhabutrensis, nov. gen., from the Late Jurassic – Early Cretaceous of Thailand is described on the basis of a collection of well‐preserved specimens. The mode of preservation of the material allows describing the external anatomy, as well as some elements of the internal anatomy (braincase, elements of the vertebral column). Most of the cranial and postcranial skeleton shows a rather conservative anatomy for ‘semionotiformes’, but the jaw apparatus displays specializations. Variations observed in the ossification pattern of the skull roof and of the cheek, in the morphology of the median dorsal scales and in fin rays’ count indicate that caution should be applied when these characters are used in diagnoses and in phylogenetic analyses. A phylogenetic analysis including a set of gars, of ‘semionotiformes’, of Macrosemiiformes and of Halecomorphi shows the following features: (1) the monophyly of Holostei; (2) sister‐pair relationships between Tlayuamichin/Semiolepis, Isanichthys/’Lepidotes’ latifrons and Araripelepidotes/Pliodetes; (3) the latter pair, together with Thaiichthys and possibly ‘Lepidotes’ mantelli, are resolved as stem Lepisosteiformes; and (4) the ‘semionotiformes’ (a group gathering species of Semionotus and Lepidotes) do not form a clade.     

Global interrelationships of Plesiosauria (Reptilia,Sauropterygia) and the pivotal role of taxon sampling in determining the outcome of phylogenetic analyses

Previous attempts to resolve plesiosaurian phylogeny are reviewed and a new phylogenetic data set of 66 taxa (67% of ingroup taxa examined directly) and 178 characters (eight new) is presented. We recover two key novel results: a monophyletic Plesiosauridae comprising Plesiosaurus dolichodeirus, Hydrorion brachypterygius, Microcleidus homalospondylus, Occitanosaurus tournemirensis and Seeleyosaurus guilelmiimperatoris; and five plesiosaurian taxa recovered outside the split between Plesiosauroidea and Pliosauroidea. These taxa are Attenborosaurus conybeari, ‘Plesiosaurus’macrocephalus and a clade comprising Archaeonectrus rostratus, Macroplata tenuiceps and BMNH 49202. Based on this result, a new name, Neoplesiosauria, is erected for the clade comprising Plesiosauroidea and Pliosauroidea. Taxon subsamples of the new dataset are used to simulate previous investigations of global plesiosaurian relationships. Based on these simulations, most major differences between previous global phylogenetic hypotheses can be attributed to differences in taxon sampling. These include the position of Leptocleididae and Polycotylidae and the monophyly or paraphyly of Rhomaleosauridae. On this basis we favour the results recovered by our, larger analysis. Leptocleididae and Polycotylidae are sister taxa, forming a monophyletic clade within Plesiosauroidea, indicating that the large‐headed, short‐necked ‘pliosauromorph’ body plan evolved twice within Plesiosauria. Rhomaleosauridae forms the monophyletic sister taxon of Pliosauridae within Pliosauroidea. Problems are identified with previous phylogenetic definitions of plesiosaurian clades and new, stem‐based definitions are presented that should maintain their integrity over a range of phylogenetic hypotheses. New, rank‐free clade names Cryptoclidia and Leptocleidia are erected to replace the superfamilies Cryptoclidoidea and Leptocleidoidea. These were problematic as they were nested within the superfamily Plesiosauroidea. The incongruence length difference test indicates no significant difference in levels of homoplasy between cranial and postcranial characters.     

A second hadrosauroid dinosaur from the early Late Cretaceous of Zuoyun,Shanxi Province,China

A second basal hadrosauroid dinosaur, Zuoyunlong huangi gen. et sp. nov., is reported from the early Late Cretaceous Zhumapu Formation in Zuoyun County, Shanxi Province, northern China. Zuoyunlong preserves a partial right ilium and ischium and is unique in having a very short postacetabular process 50% as long as the iliac central plate. Our cladistic analysis recovers Zuoyunlong as the most basal Late Cretaceous hadrosauroid, with a sister taxon relationship with Probactrosaurus from the late Early Cretaceous of Inner Mongolia. Including Zuoyunlong, four Cenomanian basal hadrosauroids have been recorded, and the two taxa in North America (Eolambia and Protohadros) represent the earliest known hadrosauroids outside of Asia. In the light of the proposed phylogenetic topology and biogeographic data, the discovery of Zuoyunlong indicates that the first dispersal of hadrosauroids from Asia to North America probably happened around the boundary between the Early and Late Cretaceous.     

Early tetrapod relationships revisited

In an attempt to investigate differences between the most widely discussed hypotheses of early tetrapod relationships, we assembled a new data matrix including 90 taxa coded for 319 cranial and postcranial characters. We have incorporated, where possible, original observations of numerous taxa spread throughout the major tetrapod clades. A stem‐based (total‐group) definition of Tetrapoda is preferred over apomorphy‐ and node‐based (crown‐group) definitions. This definition is operational, since it is based on a formal character analysis. A PAUP* search using a recently implemented version of the parsimony ratchet method yields 64 shortest trees. Differences between these trees concern: (1) the internal relationships of aistopods, the three selected species of which form a trichotomy; (2) the internal relationships of embolomeres, with Archeria crassidisca and Pholiderpeton scutigerum collapsed in a trichotomy with a clade formed by Anthracosaurus russelli and Pholiderpeton attheyi; (3) the internal relationships of derived dissorophoids, with four amphibamid species forming an unresolved node with a clade consisting of micromelerpetontids and branchiosaurids and a clade consisting of albanerpetontids plus basal crown‐group lissamphibians; (4) the position of albenerpetontids and Eocaecilia micropoda, which form an unresolved node with a trichotomy subtending Karaurus sharovi, Valdotriton gracilis and Triadobatrachus massinoti;(5) the branching pattern of derived diplocaulid nectrideans, with Batrachiderpeton reticulatum and Diceratosaurus brevirostris collapsed in a trichotomy with a clade formed by Diplocaulus magnicornis and Diploceraspis burkei. The results of the original parsimony run ‐ as well as those retrieved from several other treatments of the data set (e.g. exclusion of postcranial and lower jaw data;character reweighting; reverse weighting) ‐ indicate a deep split of early tetrapods between lissamphibian‐ and amniote‐related taxa. Colosteids, Crassigyrinus, Whatcheeria and baphetids are progressively more crownward stemtetrapods. Caerorhachis, embolomeres, gephyrostegids, Solenodonsaurus and seymouriamorphs are progressively more crownward stem‐amniotes. Eucritta is basal to temnospondyls, with crown‐lissamphibians nested within dissorophoids. Westlothiana is basal to Lepospondyli, but evidence for the monophyletic status of the latter is weak. Westlothiana and Lepospondyli form the sister group to diadectomorphs and crown‐group amniotes. Tuditanomorph and microbrachomorph microsaurs are successively more closely related to a clade including proximodistally: (1) lysorophids; (2) Acherontiscus as sister taxon to adelospondyls; (3) scincosaurids plus diplocaulids; (4) urocordylids plus aïstopods. A data set employing cranial characters only places microsaurs on the amniote stem, but forces remaining lepospondyls to appear as sister group to colosteids on the tetrapod stem in several trees. This arrangement is not significantly worse than the tree topology obtained from the analysis of the complete data set. The pattern of sister group relationships in the crownward part of the temnospondyl‐lissamphibian tree re‐emphasizes the important role of dissorophoids in the lissamphibian origin debate. However, no specific dissorophoid can be identiffed as the immediate sister taxon to crown‐group lissamphibians. The branching sequence of various stem‐group amniotes reveals a coherent set of internested character‐state changes related to the acquisition of progressively more terrestrial habits in several Permo‐Carboniferous forms.     

An investigation into the cladistic relationships and monophyly of therocephalian therapsids (Amniota: Synapsida)

A comprehensive phylogenetic investigation was performed to elucidate the cladistic relationships and possible monophyly of therocephalian therapsids (Amniota: Synapsida). The phylogenetic positions of 30 therapsid taxa were examined under maximum parsimony, including 23 therocephalian genera. The analysis incorporated 110 cranial and postcranial characters in order to assess the interrelationships of basal therocephalians and eutherocephalians and their relationships to Cynodontia, representing the most complete review of therocephalian phylogeny to date. The analysis supports the hypothesis that Therocephalia represents the monophyletic sister taxon to Cynodontia, with as many as 15 morphological synapomorphies, in contrast with other recent analyses of lesser taxon sampling. The results also support the hypothesis that Scylacosauridae is more closely related to Eutherocephalia than to the basal therocephalian family Lycosuchidae, supporting a ‘Scylacosauria’ clade. The taxa suggested here to be neotenic forms (e.g. Ictidosuchoides and Ictidosuchops) are positioned near the base of a monophyletic Baurioidea. Neotenic development of the therocephalian feeding apparatus and evolutionary parallelism with cynodonts are suggested to have been important trends in the early evolution of baurioid therocephalians into the Late Permian and Early Triassic.     

Tales of dracula ants: the evolutionary history of the ant subfamily Amblyoponinae (Hymenoptera: Formicidae)

The ants in the subfamily Amblyoponinae are an old, relictual group with an unusual suite of morphological and behavioural features. Adult workers pierce the integument of their larvae to imbibe haemolymph, earning them the vernacular name ‘dracula ants’. We investigate the phylogeny of this group with a data set based on 54 ingroup taxa, 23 outgroups and 11 nuclear gene fragments (7.4 kb). We find that the genus Opamyrma has been misplaced in this subfamily: it is a member of the leptanilline clade and sister to all other extant Leptanillinae. Transfer of Opamyrma to Leptanillinae renders the Amblyoponinae monophyletic. The enigmatic Afrotropical genus Apomyrma is sister to all other amblyoponines, and the latter cleave into two distinct and well‐supported clades, here termed POA and XMMAS. The POA clade, containing Prionopelta, Onychomyrmex and Amblyopone, is well resolved internally, and its structure supports synonymy of the genus Concoctio under Prionopelta ( syn.n. ). The XMMAS clade comprises two well‐supported groups: (i) a predominantly Neotropical clade, for which we resurrect the genus name Fulakora ( stat.r., stat.n. ), with junior synonyms Paraprionopelta ( syn.n. ) and Ericapelta ( syn.n. ); and (ii) the remaining taxa, or ‘core XMMAS’, which are manifested in our study as a poorly resolved bush of about a dozen lineages, suggesting rapid radiation at the time of their origin. Most of these XMMAS lineages have been assigned to the catch‐all genus Stigmatomma, but the more distinctive elements have been treated as separate genera (Xymmer, Mystrium, Myopopone and Adetomyrma). Resolution of basal relationships in the core XMMAS clade and reconfiguration of ‘Stigmatomma’ to restore monophyly of all named genera will require more extensive genetic data and additional morphological analysis. However, the genus Bannapone can be synonymized under Stigmatomma ( syn.n. ) because it is embedded within a clade that contains S. denticulatum, the type species of Stigmatomma. Divergence dating analysis indicates that crown Amblyoponinae arose in the mid‐Cretaceous, about 107 Ma (95% highest probability density: 93–121 Ma). The POA and XMMAS clades have estimated crown ages of 47 and 73 Ma, respectively. The initial burst of diversification in the core XMMAS clade occurred in the Late Paleocene/Early Eocene (50–60 Ma). Ancestral range reconstruction suggests that amblyoponines originated in the Afrotropics, and dispersed to the Indo‐Malayan region and to the New World. During none of these dispersal events did the ants break out of their cryptobiotic lifestyle.     

A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia

Although the group played an important role in the evolution of Late Mesozoic terrestrial ecosystems, the early evolutionary history of the ornithischian dinosaurs remains poorly understood. Here, we report on a new primitive ornithischian, Eocursor parvus gen. et sp. nov., from the Late Triassic (?Norian) Lower Elliot Formation of South Africa. Eocursor is known from a single specimen comprising substantial cranial and postcranial material and represents the most complete Triassic member of Ornithischia, providing the earliest evidence for the acquisition of many key ornithischian postcranial characters, including an opisthopubic pelvis. A new phylogenetic analysis positions this taxon near the base of Ornithischia, as the sister taxon to the important and diverse clade Genasauria. The problematic clade Heterodontosauridae is also positioned basal to Genasauria, suggesting that an enlarged grasping manus may represent a plesiomorphic ornithischian condition. This analysis provides additional phylogenetic support for limited ornithischian diversity during the Late Triassic, and suggests that several major ornithischian clades may have originated later than generally believed. There are few morphological differences between Late Triassic and Early Jurassic ornithischians, supporting previous suggestions that the Early Jurassic ornithischian radiation may simply represent the filling of vacant ecological space following Late Triassic terrestrial extinctions.     

Evolutionary relationships and systematics of Atoposauridae (Crocodylomorpha: Neosuchia): implications for the rise of Eusuchia

Atoposaurids are a group of small‐bodied, extinct crocodyliforms, regarded as an important component of Jurassic and Cretaceous Laurasian semi‐aquatic ecosystems. Despite the group being known for over 150 years, the taxonomic composition of Atoposauridae and its position within Crocodyliformes are unresolved. Uncertainty revolves around their placement within Neosuchia, in which they have been found to occupy a range of positions from the most basal neosuchian clade to more crownward eusuchians. This problem stems from a lack of adequate taxonomic treatment of specimens assigned to Atoposauridae, and key taxa such as Theriosuchus have become taxonomic ‘waste baskets’. Here, we incorporate all putative atoposaurid species into a new phylogenetic data matrix comprising 24 taxa scored for 329 characters. Many of our characters are heavily revised or novel to this study, and several ingroup taxa have never previously been included in a phylogenetic analysis. Parsimony and Bayesian approaches both recover Atoposauridae as a basal clade within Neosuchia, more stemward than coelognathosuchians, bernissartiids, and paralligatorids. Atoposauridae is a much more exclusive clade than previously recognized, comprising just three genera (Alligatorellus, Alligatorium, and Atoposaurus) that were restricted to the Late Jurassic of western Europe, and went extinct at the Jurassic/Cretaceous boundary. A putative Gondwanan atoposaurid (Brillanceausuchus) is recovered as a paralligatorid. Our results exclude both Montsecosuchus and Theriosuchus from Atoposauridae. Theriosuchus is polyphyletic, forming two groupings of advanced neosuchians. Theriosuchus (restricted to Theriosuchus pusillus, Theriosuchus guimarotae, and Theriosuchus grandinaris) spanned the Middle Jurassic to early Late Cretaceous, and is known from Eurasia and North Africa. Two Cretaceous species previously assigned to Theriosuchus (‘Theriosuchus’ ibericus and ‘Theriosuchus’ sympiestodon) are shown to be nested within Paralligatoridae, and we assign them to the new genus Sabresuchus. The revised phylogenetic placement of Theriosuchus has several implications for our understanding of eusuchian evolution. Firstly, the presence of fully pterygoidean choanae, previously regarded as a defining characteristic of Eusuchia, is not found in some basal members of Eusuchia. However, eusuchians can be distinguished from Theriosuchus and other basal neosuchians in that their choanae are posteriorly positioned, with an anterior margin medial to the posterior edge of the suborbital fenestra. This feature distinguishes eusuchians from Theriosuchus and more basal neosuchians. Secondly, our refined understanding of Theriosuchus implies that this taxon possessed only amphicoelous presacral vertebrae, and therefore fully developed vertebral procoely is likely to have evolved only once in Crocodylomorpha, on the lineage leading to Eusuchia. These and other findings presented herein will provide an important framework for understanding the neosuchian–eusuchian transition.     

Theropod and possible ornithopod track assemblages from the Jurassic–Cretaceous boundary Houcheng Formation,Shangyi, northern Hebei,China

Dinosaur track assemblages from the Houcheng Formation in the small continental Shangyi Basin of northern Hebei Province, China bridge a gap in the record of vertebrates from this unit and enrich our knowledge of ichnofaunas from the Jurassic–Cretaceous boundary. Their stratigraphic position between the Middle Jurassic Yan-Liao Biota and the Lower Cretaceous Jehol Biota gives them a special importance. New discoveries allow a re-assessment of theropod and possible ornithopod tracks that are present with several trackways. Seventy-three footprints were examined and documented. Despite their smaller size, the tridactyl mesaxonic theropod tracks show morphological similarities with the ichnogenus Therangospodus known from the Upper Jurassic deposits of North America, Europe, and Central Asia. The possible ornithopod tracks lack an associated manus imprint, suggesting a bipedal trackmaker. These possible ornithopod tracks from the Houcheng Formation provide evidence for the presence of small basal ornithopods or basal Cerapoda in the Upper Jurassic–Lower Cretaceous in this region. The depositional environment was the margin of an extensive shallow lake with fluctuating water levels under seasonally dry climate.     

Phylogeny,divergence times and biogeography of window flies (Scenopinidae) and the therevoid clade (Diptera: Asiloidea)

The evolution of the ‘therevoid’ clade, with an emphasis on window flies (Scenopinidae), is presented by combining DNA sequence data with morphological characters for living and fossil species. The therevoid clade represents a group of four families (Apsilocephalidae, Evocoidae, Scenopinidae and Therevidae) of lower brachyceran Diptera in the superfamily Asiloidea. A comprehensive phylogenetic analysis using parsimony and likelihood methods was undertaken using extensive taxon sampling from all families and subfamilies, and compared with outgroup taxa sampled from the related families Asilidae, Mydidae, Apioceridae and Empididae. Fifty‐nine morphological characters (adult, larval and pupal) were combined with 6.4 kb of DNA sequences for two ribosomal genes (16S and 18S ribosomal DNA) and three protein‐encoding genes [cytochrome oxidase I (COI), triose phosphate isomerase (TPI) and the CPSase region of carbamoyl‐phosphate synthase‐aspartate transcarbamoylase‐dihydroorotase (CAD)]. Results from combined analyses of morphological and molecular data for 78 taxa representing all families of the therevoid clade are presented. Specific hypotheses of the relationship between respective families and subfamilies were tested statistically using four‐cluster likelihood mapping. The therevoid clade is a well‐supported monophyletic group within Asiloidea, with Evocoidae sister to Apsilocephalidae and Therevidae sister to Scenopinidae. Temporal and zoogeographical aspects of therevoid clade evolution were investigated using Bayesian divergence time estimates and Lagrange ancestral range scenarios. The effect of inclusion of fossils as terminal taxa on phylogenetic and divergence time estimation was investigated, with morphological scoring for fossil representatives included in the analyses rather than used simply as minimum age constraints. In each analysis there was either improvement in estimation, or only marginal and localized loss in tree resolution, and with younger estimates of divergence time across the tree. The historical biogeography of the therevoid clade was examined with multiple trans‐Antarctic vicariance events between Australasia and South America evident during the Late Cretaceous to early Palaeogene. Scenopininae is newly subdivided into two tribes, Metatrichini trib.n. and Scenopinini Fallén stat.r. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:4974EBF8‐3117‐4189‐B6DE‐7D5BF9B23E53 .     

Increasing the number of molecular markers resolves the phylogenetic relationship of ‘Cepaea’ vindobonensis (Pfeiffer 1828) with Caucasotachea Boettger 1909 (Gastropoda: Pulmonata: Helicidae)

‘Cepaea’ vindobonensis has been shown to be closely related to Caucasotachea in recent molecular studies. The phylogenetic relationships within this clade and especially the phylogenetic position of ‘Cepaea’ vindobonensis were, however, not well resolved. Our phylogenetic analyses on the basis of an increased number of molecular genetic loci from the mitochondrial and nuclear genomes unambiguously demonstrate that ‘Cepaea’ vindobonensis represents the sister group of the Caucasotachea taxa, with C. leucoranea from the Caspian region of Azerbaijan and Iran being the sister species of the remaining Caucasian and eastern Pontic Caucasotachea species. We argue for the inclusion of ‘Cepaea’ vindobonensis in Caucasotachea rather than for a re‐erection of a monotypic genus Austrotachea for the species because of the overall low degree of morphological differentiation and the low number of species in the group.