A Late Jurassic salamander (Amphibia: Caudata) from the Morrison Formation of North America

Despite some remarkable recent discoveries, the Mesozoic fossil record of salamanders remains limited, particularly for the Jurassic. Here we describe the first articulated salamander skeleton from the Jurassic of Euramerica, recovered from Upper Jurassic deposits of the Morrison Formation, Dinosaur National Monument, USA. The specimen was studied using both conventional methods and high-resolution computed tomography. It shows a combination of primitive and derived character states that distinguish it from all known Mesozoic salamanders and which permit the erection of a new genus and species, Iridotriton hechti . The derived states (including the presence of spinal nerve foramina in the tail) suggest a position on the stem of the Salamandroidea. Together with microvertebrate material from Britain, Portugal, and North America, this specimen confirms the presence of both stem- and crown-group salamanders in Euramerica from the Middle Jurassic (Bathonian) onwards, paralleling their evolution in Central and eastern Asia. This, in turn, provides qualified support for the current vicariance model of salamander evolution whereby basal caudates on an undivided Laurasian plate became separated into two populations by the incursion of the Turgai Sea in the Middle Jurassic, yielding Cryptobranchoidea in Asia and Salamandroidea in Euramerica.  © 2005 The Linnean Society of London , Zoological Journal of the Linnean Society , 2005, 143 , 599−616.     

Monophyly and affinities of albanerpetontid amphibians (Temnospondyli; Lissamphibia)

The Albanerpetontidae are Middle Jurassic-Miocene amphibians that have variously been regarded as caudates (salamanders), a clade distinct from caudates, or incertae sedis lissamphibians. Here I test for monophyly of the Albanerpetontidae and examine the affinities of the group, within the framework of a more inclusive Temnospondyli, by performing a cladistic analysis using 59 informative characters scored for four non-lissamphibian temnospondyl genera, stem- and crown-clade caudates, salientians (frogs), gymnophionans (caecilians), and the two recognized albanerpetontid genera Albanerpeton and Celtedens . Monophyly of the Albanerpetontidae is corroborated. I interpret synapomorphies of the marginal teeth (non-pedicellate; crowns chisel like, labiolingually compressed, with three mesiodistally aligned cuspules) in albanerpetontids as being associated with a shearing bite. Other synapomorphies evidently strengthened and increased the mobility of the skull, mandible, and cervical region for burrowing, feeding, or both. Nested sets of synapomorphies place the Albanerpetontidae within the Lissamphibia, as the sistertaxon of Caudata plus Salientia. None of the 17 characters previously advanced as albanerpetontid-caudate synapomorphies convincingly places the Albanerpetontidae within the Caudata or allies the two groups as sistertaxa. Albanerpetontids are better interpreted not as aberrant caudates, but as a distinct clade of lissamphibians in which numerous apomorphies are superimposed upon an otherwise primitive lissamphibian body plan.     

Similarity

Recent debates concerning conflicting hypotheses of higher-level phylogeny such as the sister-group relationships of tetrapods, turtles, birds and snakes, serve as examples in the analysis of the nature of morphological evidence as it is currently used in phylogeny reconstruction. We note a recent shift of emphasis towards ever-larger data matrices, which may come at the cost of detailed character analysis and argumentation. Because the assessment of morphological characters necessarily entails a conceptual element of abstraction, there is also a threat that preconceived notions of phylogeny influence character analysis. Because the test of congruence does not address character analysis in itself, we argue that character hypotheses, i.e. primary conjectures of homology, need to be testable, and potentially refutable, in their own right. We demonstrate the use of classical criteria of homology (topological relations and/or connectivity, in conjunction with the subsidiary criteria of special similarity and intermediate forms) in the test, and refutation, of morphological characters. Rejection of the classical criteria of homology in the test of morphological character hypotheses requires the formulation of alternative methods of test and potential falsification of morphological characters that have so far not been proposed. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 59–82.     

The evolution of release and advertisement calls in green toads (Bufo viridis complex)

In the present paper we tested the hypothesis that differences in the acoustic communication system of diploid and tetraploid green toads ( Bufo viridis complex) might be due to selection for reproductive character displacement. We recorded two acoustic signals of the toad repertoire − the advertisement call (a long range mate-attracting signal) and the release call (a short-range signal mediating male–male interactions) − from six sympatric Central Asian populations (three diploid and three tetraploid populations) as well as from three allopatric diploid populations from Italy, and compared their patterns of variation with the pattern of among-population genetic distances. Although release and advertisement calls share the same morpho-physiological constraints, they show significantly different patterns of variation. Release calls vary congruently with the pattern of genetic distances, suggesting that mutation and genetic drift have been the major forces responsible for their change both in time and space. By contrast, the pattern of advertisement-call variation is not consistent with the phylogeny of the group, because the advertisement calls of Asian diploid and tetraploid populations differ from each other more than their genetic distances would predict. These results strongly support the hypothesis that selection acted on the advertisement calls of either or both Asian taxa , possibly, to favour reproductive isolation.  © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77, 379–391.     

A new species of Halisaurus from the Late Cretaceous phosphates of Morocco, and the phylogenetical relationships of the Halisaurinae (Squamata: Mosasauridae)

A new species of the basal mosasaurid Halisaurus from the Late Cretaceous (Late Maastrichtian) of the Oulad Abdoun Phosphate Basin of Morocco is described on the basis of both cranial and postcranial remains. H. arambourgi sp. nov. is characterized by unique features of the nares, frontal, parietal, girdle and limb bones. A phylogenetical analysis supports the monophyletic status of Halisaurus ; H. platyspondylus (Maastrichtian, New Jersey), H. ortliebi (Maastrichtian, Belgium) and H. arambourgi form an unresolved polytomy. This study does not support the attribution of ' Halisaurus ' sternbergii (Santonian, Kansas) to Halisaurus nor to any known genus. A new genus, Eonatator , is proposed for the reception of this species, Eonatator sternbergii comb. nov. The new taxon Halisaurinae ( Halisaurus  +  Eonatator ) is the sister-group of more advanced mosasaurids (Natantia). Halisaurines are defined by the shape of the lateral premaxilla–maxilla suture; an oblique contact plane between the parietal and the supratemporal; a preaxial ridge present on the distal two-thirds of the radius length; and tibia and fibula long and slender with slightly expanded extremities.  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 143 , 447–472.     

Genets and 'genet-like' taxa (Carnivora, Viverrinae): phylogenetic analysis, systematics and biogeographic implications

The subfamily Viverrinae is a taxon of uncertain systematic status. This study consists of cladistic analyses based on morphological characters of specimens belonging to the genera Genetta , Osbornictis , Poiana and Prionodon . Two levels of analysis are carried out, one concerning generic relationships (intergeneric analysis) and one dealing with the interrelationships of species within the genus Genetta (intrageneric analysis). In the first analysis, different outgroups were used in order to test the ingroup topology.
With regard to the intergeneric analysis, Osbornictis , Poiana and Prionodon , together with Genetta johnstoni , constitute a monophyletic group (including Nandinia ), which is the sister-group of a clade formed by the other species of genets. Thus, the genus Genetta is regarded as paraphyletic. Prionodon appears to be a derived taxon. The Poiana – Prionodon clade is well supported, especially by ultrastructural hair characters. The cladogram topology in the intrageneric analysis indicates an ecological transition from the rain forest genets to the savanna genets. This supports a rain forest origin of the genus Genetta , a conclusion which may be generalized to the entire study group. © 2002 The Linnean Society of London, Zoological Journal of the Linnean Society , 2002, 134 , 317–334.     

Crocodilus affuvelensis Matheron, 1869 from the Late Cretaceous of southern France: a reassessment

Hitherto unpublished crocodylian remains, including four skull fragments, from the lignite-bearing localities of Valdonne and Fuveau (Santonian–Campanian), south-eastern France, are described. They complement the original material of ' Crocodilus affuvelensis ' described by Matheron (1869) and Repelin (1930). Based on overlapping specimens, available elements of the rostrum, the palate, the skull table, the mandible and the pterygoid can be shown to belong to a single taxon, for which a reconstruction is proposed. Designation of a neotype has been proposed to the ICZN committee. A new genus, Massaliasuchus , is proposed here to designate the crocodylian originally described as Crocodilus affuvelensis . This crocodylian presents affinities with basal alligatoroids and complements the picture of crocodylian diversity during the Late Cretaceous in the European archipelago. Massaliasuchus affuvelensis is compared with other European taxa and with basal alligatoroids from North America. The putative basal position of Massaliasuchus as well as its early geological age suggest that the geographical origin of the Alligatoroidea is still uncertain.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 567–580.     

Locomotion in terrestrial mammals: the influence of body mass, limb length and bone proportions on speed

Traditionally a few limb proportions or total limb lengths have been regarded as indicative of peak running velocity. This is due to physical principles (inferred in- and outvelocities around the joints, stride lengths) and also the observation that fast-moving animals tend to share a number of purported key features which are either absent or not developed to near the same extent in slower moving forms. Previous studies have shown hind limb length and metatarsus/femur ratio to be correlated significantly, albeit modestly with running speed. These studies have nearly all been bivariate analyses. Based on the physical principles, there is reason to suppose that more variables than just m/f ratio could be important as adaptations for fast locomotion, and also that bivariate analyses are too simple. In this study a sample of 76 running mammals was used, with running speeds taken from literature. A number of osteological parameters were discovered to covary significantly with peak running speed, albeit only modestly. Using the information from phylogeny reduced all correlations, often significantly so. Multivariate analyses resulted in markedly higher correlation coefficients. Animals probably do not optimize their anatomy for the purpose of running very fast, which occurs only on rare occasions, but for reducing costs of locomotion.  © 2002 The Linnean Society of London, Zoological Journal of the Linnean Society , 2002, 136 , 685–714.     

The pollen cones of Ginkgo from the Early Cretaceous of China, and their bearing on the evolutionary significance

A well-preserved pollen cone of the genus Ginkgo was found in the Yixian Formation (Early Cretaceous) of Liaoning Province, China, and is described as the new species Ginkgo liaoningensis . The pollen cone, catkin-like, consists of a main axis bearing scales at its base and spirally arranged sporophylls bearing 3–4 (−2) oval or elliptical sporangia. The sporangia are pendulous and dehiscent by a longitudinal slit. The mature pollen grains are monocolpate and elongate-elliptical, and the juvenile pollen grains are found in the tetrad stage. The characteristics of G. liaoningensis are very similar to those of the living Ginkgo biloba , but the sporophylls of G. liaoningensis bear 3–4 (−2) sporangia, whereas those of G. biloba bear mostly two sporangia. G. liaoningensis differs from fossil cones of Ginkgo huttoni from the Jurassic of Yorkshire, UK, and an unnamed specimen of Ginkgo from the Upper Cretaceous of Alberta, Canada, in the size and number of sporangia. The comparison between G. liaoningensis (fossil) and G. biloba (living) supports the reduction hypothesis of ovule organs in Ginkgo , with the number of sporangia having experienced the process of reduction from three or four to two since the Early Cretaceous.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 133–144.     

The First Freshwater Mosasauroid (Upper Cretaceous,Hungary) and a New Clade of Basal Mosasauroids

Mosasauroids are conventionally conceived of as gigantic, obligatorily aquatic marine lizards (1000s of specimens from marine deposited rocks) with a cosmopolitan distribution in the Late Cretaceous (90–65 million years ago [mya]) oceans and seas of the world. Here we report on the fossilized remains of numerous individuals (small juveniles to large adults) of a new taxon, Pannoniasaurus inexpectatus gen. et sp. nov. from the Csehbánya Formation, Hungary (Santonian, Upper Cretaceous, 85.3–83.5 mya) that represent the first known mosasauroid that lived in freshwater environments. Previous to this find, only one specimen of a marine mosasauroid, cf. Plioplatecarpus sp., is known from non-marine rocks in Western Canada. Pannoniasaurus inexpectatus gen. et sp. nov. uniquely possesses a plesiomorphic pelvic anatomy, a non-mosasauroid but pontosaur-like tail osteology, possibly limbs like a terrestrial lizard, and a flattened, crocodile-like skull. Cladistic analysis reconstructs P. inexpectatus in a new clade of mosasauroids: (Pannoniasaurus (Tethysaurus (Yaguarasaurus, Russellosaurus))). P. inexpectatus is part of a mixed terrestrial and freshwater faunal assemblage that includes fishes, amphibians turtles, terrestrial lizards, crocodiles, pterosaurs, dinosaurs and birds.     

Fossil palm flowers in Dominican and Mexican amber

Twelve palm flowers in one piece of Dominican amber and a single flower in a second piece are described as Trithrinax dominicana sp. nov. (Thrinacinae: Coryphoideae), representing the first fossil record of this genus. There are no members of Trithrinax in the Greater Antilles today. Two staminate flowers in Mexican amber are described as Socratea brownii sp. nov. (Iriarteinae: Arecoideae) and represent the first fossils of this genus. A third palm flower in Mexican amber, possibly belonging to the subtribe Euterpeinae, is characterized. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 138 , 57–61.     

Variation across amphibian species in the size of the nuclear genome supports a pluralistic, hierarchical approach to the C-value enigma

Amphibians have featured prominently in discussions of the C-value enigma, the still-unresolved puzzle regarding the evolution of genome size. Their wide range in nuclear DNA contents and diverse ecological and developmental lifestyles make them excellent subjects for addressing the key elements of the C-value enigma. However, in some cases the importance of work on amphibians appears to be overstated. This is especially true of claims that patterns of variation in salamanders support a particular theory of genome size evolution to the exclusion of others. This study provides a critical re-examination of some of these claims, as well as an investigation of the relationships between genome size, cell and nuclear size, and metabolism in amphibians. The results of these analyses, combined with an overview of previous amphibian genome size literature, strongly indicate the need for a pluralistic approach to the C-value enigma. In particular, it must be recognized that evolutionary forces operating and interacting at several levels of biological organization (of which the genome itself is one) are responsible for the observed patterns in amphibian genome size distributions.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79 , 329–339.     

Is the enigma a variation? Sagina boydii F. B. White (Caryophyllaceae), Boyd's pearlwort

Sagina boydii F. B. White (Caryophyllaceae), Boyd's pearlwort, is an enigmatic taxon of unknown geographical origin which is only known in cultivation and is of uncertain taxonomic status. Morphological, cytological and geographical evidence suggests that it is most similar to S. procumbens L. and S. saginoides (L.) H. Karst., but it differs in its compact growth form. Genetically, AFLP analysis shows that it can be included as part of the variation in S. procumbens . In cultivation, it will grow true from seed. Other compact growth forms occur in S. procumbens but do not grow true from seed. As S. boydii is part of the variation in S. procumbens , is of uncertain geographical origin, is known only in cultivation, and grows true from seed, it is best treated as a new cultivar, Sagina procumbens 'Boydii'. A neotype and standard specimen is designated.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 203–211.     

The origin of modern amphibians: a re‐evaluation

There are currently three competing hypotheses seeking to explain the evolutionary origins of modern amphibians. The lepospondyl hypothesis holds that the lysorophian lepospondyls constitute the sister taxon to all lissamphibians. The temnospondyl hypothesis suggests that modern amphibians are most closely related to the dissorophoid temnospondyls. Finally, the polyphyletic hypothesis posits that the modern amphibian orders have separate evolutionary origins from among different groups of Palaeozoic tetrapods. Here, we review the character matrices used in previous studies. These data sets differ significantly in choice of characters. Therefore, we built a matrix based on data from all three hypotheses and analysed key taxa phylogenetically using both Bayesian inference and parsimony. Uncorrected, the supermatrix yielded inconclusive results, demonstrating the presence of at least two phylogenetic optima. When the data were corrected according to new observations on Doleserpeton, Eocaecilia, and other fossil forms, the phylogeny supported the temnospondyl hypothesis of lissamphibian origins. This conclusion is also supported by a careful study of character changes in the individual lineages. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 162 , 457–469.     

Melanic frequencies in three species of moths in post industrial Britain

Changing patterns of morph frequency in three moth species ( Biston betularia , Odontoptera bidentata and Apocheima pilosaria ) have been investigated using data from the Rothamsted Insect Survey. All three exhibited industrial melanism during the period of high atmospheric pollution in Britain. Three historical and habitat types are compared, the old industrial north of England, rural Scotland, Wales and South-West England, and a southern English intermediate region of high human population density but generally low industrialization. Between 1974 and 1999 the carbonaria morph of B. betularia declined in frequency in the industrial region and is nearly absent from rural areas. It is the form which most closely tracks atmospheric change. It is shown that the insularia forms of B. betularia and the melanic morphs in the other two species have decreased in the industrial region, commencing later than carbonaria , but have maintained their presence and possibly reached equilibrium elsewhere. They may be non-industrial polymorphisms. B. betularia is rarer than the other species and all three species are at lower densities in industrial than in non-industrial regions. © 2002 The Linnean Society of London , Biological Journal of the Linnean Society , 2002, 75 , 475–482.     

The intersectional hybrid between Weigela hortensis and W. maximowiczii (Caprifoliaceae)

Morphologically intermediate plants between Weigela hortensis (Siebold & Zucc.) K.Koch and W. maximowiczii (S.Moore) Rehder have been found in Miyagi and Yamagata Pref., northern Japan. Quantitative character analyses of flowers, pollen stainability and molecular analyses indicated that the intermediate plants were hybrids of those two species. This is the first record of an intersectional hybrid with W. maximowiczii (sect. Weigelastrum ) as one of the parent species. The morphological differences among hybrid individuals imply the possibility of backcrosses or formation of second or later generations of hybrids, although those may be quite rare because of a low frequency of viable pollen grains. Causes of hybridization between two distantly-related species in Weigela are discussed. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 369–380.     

Morphological segregation of Icelandic threespine stickleback (Gasterosteus aculeatus L).

Icelandic threespine sticklebacks show parallel sympatric morphological differences related to different substrate habitats in four Icelandic lakes. The level of morphological diversification varies among the lakes, ranging from a population with a wide morphological distribution to a population with clear resource morphs, where morphological diversification was reflected in diet differences. These differences in morphological divergence are closely related to the differences in the ecological surroundings of each population. This appears to be resource polymorphism, which may lead to population differentiation and speciation. Trophically related sexual dimorphism was also common in these sticklebacks, which is possibly the result of sexual selection or habitat segregation by the sexes. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 76 , 247–257.     

Amphi-Atlantic distribution of the Mancocumatinae (Cumacea: Bodotriidae), with description of a new genus dwelling in marine lava caves of Tenerife (Canary Islands)

A new cumacean genus and species, Speleocuma guanche gen et sp. nov. , belonging to the subfamily Mancocumatinae Watling 1977 , is described from marine lava caves of Tenerife, Canary Islands. This genus differs from others in the subfamily in having two pairs of pleopods in males and exopods on first to third pereopods, but not on fourth pereopod, in both sexes. Correlation between phylogenetic relationships of the new genus and the geological history of the Canarian archipelago points to a probable origin of this endemism: the subfamily Mancocumatinae show a disjunct distribution on both sides of the Atlantic Ocean, a pattern which has been associated with fauna of Tethyan origin. It is suggested that present-day genera of the subfamily evolved from a common shallow water ancestor living in the late Mesozoic ( c . 120 Myr BP), when the opening of the Atlantic Ocean had begun. It survived in shallow waters off the west African coast before the emergence of the Canary Islands from the sea floor. Later on, between the late Cretaceous and the Mio-Pliocene, it was able to colonize crevicular habitats of the eastern Canary Islands through continental or land bridges. Finally, their numbers increased to occupy more recent biotops like flooded lava tube caves as well as westward islands such as Tenerife. © 2002 The Linnean Society of London. Zoological Journal of the Linnean Society , 2002, 134 , 453–461.