Terrestrial locomotion in monotremes (Mammalia: Monotremata)

Cineradiographic analysis of the limb movements of Ornithorhynchus reveals that the proximal limb bones undergo horizontal retraction, long-axis rotation and distal elevation (humerus) or depression (femur) during the propulsive phase of walking. Cinematographic records show that the locomotor movements of Ornithorhynchus differ in several respects from those of Tachyglossus and Zaglossus which are essentially similar. Comparison of the propulsive phase limb movements of Ornithorhynchus with those previously established radiographically for Tachyglossus reveals that the humerus is on average less laterally but more dorsally directed, and that the femur is on average more dorsally and slightly more laterally directed in Ornithorhynchus . Comparison of the limb orientations of monotremes with those empirically determined in therian mammals and lepidosaurian reptiles indicates that monotremes are most similar to therians. Consideration of several evidently derived features of the appendicular skeleton of monotremes leads to the conclusion that the limb orientations used by early mammals were probably similar to those used by locomotively generalized living therians, and that monotremes show modifications of this.     

The systematic position of monotremes reconsidered (Mammalia)

Summary By reinterpretation of the tooth formula ofOrnithorhynchus as dp/P M_1–4 a synapomorphy with Marsupials has been discovered. Monotremes and Marsupials are sister groups, together derived from Theria of the Middle-Crelaceous.     

Seasonal patterns in water, sodium and energy turnover in free-living echidnas, Tachyglossus aculeatus (Mammalia: Monotremata)

The energetics of an egg-laying mammal, the echidna ( Tachyglossus aculeatus ), were studied in the wild by means of isotope turnover techniques. Water and sodium influx rates were highest in summer (47.7±15.3 ml kg^-1 day^-1 and 1.20±0.52 mmol kg^-1 day^-1, respectively) and associated with high metabolic rates (0.509±0.048 ml CO₂ g^-1 h^-1). Water and sodium influxes and metabolic rates were lowest in May and June (7.8±6.4 ml H₂O kg^-1 day^-1, 0.21±0.12 mmol Na kg^-1 day^-1 and 0.205±0.129 ml CO₂ g^-1 h^-1, respectively). These low rates in late autumn/early winter are associated with reduced activity, the animals spending substantial periods of time in torpor. The comparatively low isotope turnover rates of echidnas are a consequence of their diet; ants and termites which have low mass-specific energy contents.     

A phylogenetic estimate for golden moles (Mammalia,Afrotheria, Chrysochloridae)

Background  

Golden moles (Chrysochloridae) are small, subterranean, afrotherian mammals from South Africa and neighboring regions. Of the 21 species now recognized, some (e.g., Chrysochloris asiatica, Amblysomus hottentotus) are relatively common, whereas others (e.g., species of Chrysospalax, Cryptochloris, Neamblysomus) are rare and endangered. Here, we use a combined analysis of partial sequences of the nuclear GHR gene and morphological characters to derive a phylogeny of species in the family Chrysochloridae.     

On the phylogenetic position of the Okinawa woodpecker (Sapheopipo noguchii)

The Okinawa woodpecker Sapheopipo noguchii is the rarest extant woodpecker species. The monotypic genus Sapheopipo was considered to be a representative of an old lineage of woodpeckers that led to the Eurasian genera Picus and the Blythipicus–Gecinulus species. This view, based on similarities in color patterns, external morphology and foraging behavior, has been adopted in all major accounts of the family. The alternative view, that this woodpecker may be related to the widespread white-backed woodpecker Dendrocopos leucotos, which evolved distinctive subspecies on other East Asian islands, has not been generally accepted. We analyzed partial sequences of the mitochondrial cytochrome b (cyt b) gene to test these hypotheses. The data suggest that the Okinawa woodpecker is a member of the genus Dendrocopos, with white-backed woodpecker and great spotted woodpecker D. major as close relatives. Color patterns support the genetic results and indicate a closer relationship with the white-backed woodpecker. Consequently, the correct taxonomic designation of the Okinawa woodpecker would be Dendrocopos noguchii (Seebohm in Ibis 5(5):173–182, 1887) in the tribe Campetherini rather than Picini.This revised version was published online in February 2005 with corrections to tables 1 and 2.     

On the phylogenetic position of the scrub-birds (Passeriformes: Menurae: Atrichornithidae) of Australia

Evolutionary relationships of the scrub-birds Atrichornis were investigated using complete sequences of the recombination-activating gene RAG-1 and the proto-oncogene c-mos for two individuals of the noisy scrub-bird Atrichornis clamosus. Phylogenetic analysis revealed that Atrichornis was sister to the genus Menura (the lyrebirds) and that these two genera (the Menurae) were sister to the rest of the oscine passerines. A sister relationship between Atrichornis and Menura supports the traditional view, based on morphology and DNA hybridization, that these taxa are closely related. Similarly, a sister relationship with the remaining oscine passerines agrees with the morphological distinctiveness of Atrichornis and Menura, although this result contradicts conclusions based on DNA hybridization studies. Although Atrichornis is very well known morphologically, previous conclusions regarding its relationships were hampered by a lack of comparative knowledge of other passerines, making concurrence of the sequence data of particular significance.     

On the phylogeny and zoogeography of the leptarctines (Carnivora,Mammalia)

A restudy of the skull and mandible ofLeptarctus neimenguensis Zhai from the Middle Miocene of China and the preparation of its auditory region led to the recognition of new features. The most important among them is the presence of a small suprameatal fossa partly hidden in the bony mastoid process corresponding to the structure described inPlesiogale andParagale (Schmidt-Kittler 1981) and representing the most primitive type of the mustelid middle ear. A detailed comparison of the dentition revealed thatTrocharion albanense Major from the European Miocene is closely related toLeptarctus so that is has to be included in the leptarctines. On the basis of special synapomorphies, the Mustelidae can be devided in two (holo-) monophyletic subunits of the next lower level: The first group is represented by the leptarctines (includingTrocharion), whereas the second group comprises all Recent mustelids and its forerunners. The splitting of these groups must have taken place still before the end of the Oligocene. On various grounds it is argued the leptarctines are of Eurasian origin.     

Proopiomelanocortin (POMC) and testing the phylogenetic position of turtles (Testudines)

Morphological and molecular studies have inferred multiple hypotheses for the phylogenetic relationships of Testudines. The hypothesis that Testudines are the only extant anapsid amniotes and the sister taxon of diapsid amniotes is corroborated by morphological studies, while the hypothesis that Testudines are diapsid amniotes is corroborated by more recent molecular and morphological studies. In this study, the placement of Testudines is tested using the full length cDNA sequence of the polypeptide hormone precursor proopiomelanocortin (POMC). Because only extant taxa have been used, the hypotheses being tested are limited to the following (1) Testudines as the sister taxon of Archosauria, (2) Testudines included in Archosauria and the sister taxon of Crocodilia, (3) Testudines as the sister taxon of Lepidosauria, (4) Testudines as the sister taxon of Sauria, and (5) Testudines as the sister taxon of a monophyletic Mammalia–Sauria clade. Neither Maximum likelihood, Bayesian, or maximum parsimony analyses are able to falsify the hypothesis of (Archosauria (Lepidosauria, Testudines)) and as such is the preferred inference from the POMC data.     

Magnetic resonance microscopy of prenatal dolphins (Mammalia, Odontoceti, Delphinidae) - Ontogenetic and phylogenetic implications

The structure of two preserved prenatal dolphins were visualized by 3D MR microscopy (isotropic nominal resolution up to 78.1 μm), which is a high-resolution 3D magnetic resonance imaging (MRI) technique. To determine the benefits and limitations of this method, the acquired 3D datasets were segmented manually and compared to histological sections of different specimens in corresponding developmental stages. The MR images visualize the external and internal morphology of both prenatal dolphins in detail. Various organ systems with their main components are clearly documented in the images, allowing a complete segmentation of the specimens and the calculation of volumes and surface areas of different organ systems. Due to its non-invasive character and the detailed imaging within its resolution range, MR microscopy proves to be a valuable tool in developmental biology for the visualization of the inner architecture of rare and delicate museum specimens, such as the small dolphin embryo and fetus examined. In these two prenatal dolphins, the profound structural modifications at the transition from the embryonic to the fetal stage reflect the adaptations of the mammalian bauplan to the requirements of a holaquatic cetacean life-style. However, the developmental pattern and sequence of the emerging tissues and organs in prenatal life do not resemble the hypothesized evolution of the structural and functional adaptations found in the fossil record.     

Miocene Sanitheriidae (Suiformes, Mammalia) from Namibia and Kenya: systematic and phylogenetic implications

Sanitheres are enigmatic small suoids with bunoselenodont cheek teeth and a tendency for complication of the premolars by polycuspy and polycristy. Until a few years ago virtually nothing was known about their anterior dentition, but recent discoveries in Greece, Kenya and Namibia have thrown light on their incisor and canine morphology, and reveals among other things that the canines are highly sexually dimorphic, and the dm/1 is replaced by a p/1. Material from Kipsaraman, Kenya, collected between 1997 and 2003, consists of parts of mandibles and many isolated teeth, including elements of the deciduous dentition, a significant proportion of which are unworn. These new finds confirm the aberrant nature of the sanithere dentition within a suoid framework, and support their classification as a family separate from Suidae and Palaeochoeridae (= Old World Tayassuidae).

Résumé

Les sanithères sont de petits Suoïdes aux dents jugales bunosélénodontes avec des prémolaires qui présentent une tendance à la multiplication des cuspides et des crêtes (“polycuspidie” et la “polycristie”). Jusqu’à récemment, on ne connaissait rien sur la morphologie de leur dentition antérieure, mais des découvertes récentes réalisées en Grèce, au Kenya et en Namibie, lèvent le voile sur la morphologie de leurs incisives et de leur canine. Ainsi, il apparaît que les canines sont très dimorphes et que la dm/1 inférieure est remplacée par une p/1. Le matériel de Kipsaraman au Kenya, récolté entre 1997 et 2003, consiste en des fragments de mandibules et de nombreuses dents isolées, dont des dents déciduales, qui pour la plus grande part ne sont pas usées. Ces nouveaux fossiles confirment la nature aberrante de la dentition des sanithères au sein des Suoidea, et supporte leur classification dans une famille distincte des Suidae, et des Palaeochoeridae (= Tayassuidae de l’Ancien Monde).     

Homoplasy in the ear region of Tethytheria and the systematic position of Embrithopoda (Mammalia,Afrotheria)

The ear region of mammals has long been considered as morphologically very conservative and accordingly, phylogenetically useful. In this study, the anatomy of the petrosal and bony labyrinth (osseous inner ear) of Numidotherium (Proboscidea) and Arsinoitherium (Embrithopoda) are investigated and compared in order to assess the evolution of ear region characters in proboscideans and embrithopods. Using a cladistic analysis across Paenungulata based on ear region characters only, we found that Arsinoitherium is surprisingly best placed as a crown proboscideans to the exclusion of Numidotherium and Phosphatherium, which results in the paraphyly of proboscidean. The clade Proboscidea is actually well supported by dental and post-cranial characters, and we propose that this result underlines the great amount of morphological convergences in the ear region of Embrithopoda and Proboscidea, possibly due to convergent evolution of capabilities toward infrasonic hearing.     

The hyo-laryngeal complex of Tarsius bancanus (Mammalia, Primates): a developmental and phylogenetic aspect

The present approach reconstructed the hyo-laryngeal complex of fetal Tarsius bancanus by using the AMIRA 3.1.1 software. Our work fills a gap of ontogenetic research as this region has only been superficially described for an adult specimen representing the same genus. Furthermore, based on 51 characters we conducted several cladistic analyses considering the "Prosimii"/Haplorrhini-debate. Some anatomical information has been taken from the literature. MacClade 4.06 was used in order to measure TL-, CI-, and RC-values of these two competing hypotheses, however, resulting in equal support. A PAUP 4.02b parsimony analysis based on the Haplorrhini-hypothesis showed a significant bootstrap-value: the Pan and Alouatta-clade was supported with 90 % in spite of the highly derived morphology of the howler monkey. This fact reflects the importance of fetal data for systematic research. The study might serve as a morphological basement for further experimental studies of vocal communication.     

Comparative study of the phylogenetic structure in six Apodemus species (Mammalia,Rodentia) inferred from ISSR-PCR data

The utility of the Inter Simple Sequence Repeat-Polymerase Chain Reaction (ISSR-PCR) was explored in order to determine genetic variation in six species of the genus Apodemus (A. flavicollis, A. sylvaticus, A. uralensis, A. agrarius, A. mystacinus and A. epimelas) at the individual level, population level, in separate geographic samples and in the species as a whole. Six optimized primers produced highly reproducible and polymorphic DNA markers with 98.3% polymorphic bands on a total sample of 91 individuals from 32 localities in Europe and Asia. Moreover, each primer allowed for an exact diagnosis of each of the six Apodemus species and thus provides a simple and reliable tool for the hitherto problematic discrimination of species from the subgenus Sylvaemus. Genetic distances between species ranged from 0.079, among the closely related A. flavicollis and A. sylvaticus, to 0.203 between A. mystacinus and A. agrarius. A. flavicollis, A. uralensis and A. sylvaticus display a strong population substructure. The range of genetic distances among geographic samples within last two species reaches the values obtained for closely related species. ISSR markers proved to be a simple and reliable tool for species diagnosis, as well as for estimating genetic diversity below the species level and for closely related species, but they showed questionable reliability for larger genetic distances.     

On the phylogenetic relationships of trogons (Aves, Trogonidae)

Although trogons (Aves, Trogonidae) are well characterized by the possession of heterodactyl feet, their phylogenetic relationships to other extant birds still are only poorly understood. Molecular studies did not show conclusive results and there are amazingly few comparative studies of the anatomy of trogons. Virtually the only hypothesis on trogon relationships that was supported with derived morphological characters is a sister group relationship to alcediniform birds (bee-eaters, kingfishers, and allies), which share a derived morphology of the columella (ear-ossicle) with trogons. However, in this study a very similar columella is reported for the oilbird (Steatornithidae) and additional previously unrecognized derived osteological characters are presented, which are shared by trogons and oilbirds. A numerical cladistic analysis of 28 morphological characters also resulted in monophyly of Trogonidae and Steatornithidae, although the corresponding node was not retained in a bootstrap analysis.     

Spermiogenesis in Bythonomus lemani and the phylogenetic position of the Lumbriculidae (Oligochaeta,Annelida)

Spermiohistogenesis and spermatozoal morphology of the lumbriculid Bythonomus lemani have been investigated by means of electron microscopy. Though spermiohistogenetic events follow the general microdrile pattern, some features are peculiar: chromatin is clumped in the first stages and its condensation is very irregular, as in Eisenia. Manchette geometry is similar to that of hirudineans, as the microtubules are helically arranged from the very early stages. A number of mitochondria are always present in the collar region.The mature sperm also departs from the microdrile model and is more similar to the megadrile one in (1) the strong withdrawal of the base of the acrosome vesicle into the acrosome tube; (2) the apparent development of rudimentary connectives. On the other hand, some features seem to be unique among oligochaetes, including the inclined longitudinal axis of the axial rod and tilted anterior end of the nucleus.Spermatologically, lumbriculids may be interpreted as advanced microdriles which may be descended from a stock which also gave rise to Haplotaxidae, Moniligastridae, and the true Opisthopores.     

On the phylogenetic position of insects in the Pancrustacea clade

The current views on the phylogeny of arthropods are at odds with the traditional system, which recognizes four independent arthropod classes: Chelicerata, Crustacea, Myriapoda, and Insecta. There is compelling evidence that insects comprise a monophyletic lineage with Crustacea within a larger clade named Pancrustacea, or Tetraconata. However, which crustacean group is the closest living relative of insects is still an open question. In recent phylogenetic trees constructed on the basis of large gene sequence data insects are placed together with primitive crustaceans, the Branchiopoda. This topology is often suspected to be a result of the long branch attraction artifact. We analyzed concatenated data on 77 ribosomal proteins, elongation factor 1A (EF1A), initiation factor 5A (eIF5A), and several other nuclear and mitochondrial proteins. Analyses of nuclear genes confirm the monophyly of Hexapoda, the clade uniting entognath and ectognath insects. The hypothesis of the monophyly of Hexapoda and Branchiopoda is supported in the majority of analyses. The Maxillopoda, another clade of Entomostraca, occupies a sister position to the Hexapoda + Branchiopoda group. Higher crustaceans, the Malacostraca, in most analyses appear a more basal lineage within the Pancrustacea. We report molecular synapomorphies in low homoplastic regions, which support the clade Hexapoda + Branchiopoda + Maxillopoda and the monophyletic Malacostraca including Phyllocarida. Thus, the common origin of Hexapoda and Branchiopoda and their position within Entomostraca are suggested to represent bona fide phylogenetic relationships rather than computational artifacts.     

Les Lagomerycidae (Artiodactyla, Mammalia) de FranceThe French Lagomerycidae (Cervoidea, Artiodactyla, Mammalia)

The Lagomerycidae, a small family of the Cervoidea, is known in France by the genera Lagomeryx, Ligeromeryx and Stephanocemas. Lagomeryx contains three species, the other two genera one species only. This family is known from MN3 to MN5.