Tracking down the lizards from Gravenhorst's collection at the University of Wrocław: type specimens of Callopistes maculatus Gravenhorst, 1838 and three Liolaemus species rediscovered

Johann Ludwig Christian Gravenhorst’s herpetological collection at the Museum of Natural History, University of Wrocław included numerous important specimens of amphibians and reptiles. The majority, if not the entirety, of this collection has long been thought to be lost. However, we were able to rediscover some type specimens of lizards. The rediscovered specimens include the holotypes of Liolaemus conspersus and L. hieroglyphicus, one syntype of Callopistes maculatus (here designated as the lectotype) and two syntypes of L. lineatus (one of which is herein designated as the lectotype). Reexamination of these specimens indicates that previous synonymies proposed for L. conspersus and two syntypes of L. hieroglyphicus are problematic; furthermore, more complex taxonomic work is needed to resolve this issue. Two rediscovered syntypes of L. lineatus differ in several scalation traits and are possibly not conspecific. The type specimens of several other species of lizards from Gravenhorst’s collection (Liolaemus marmoratus, L. unicolor and two other syntypes of L. lineatus, Leiocephalus schreibersii and Chalcides viridanus) were not found and are probably lost

Morfologia kontra molekuły - o konflikcie pomiędzy hipotezami filogenetycznymi na przykładzie łuskonośnych

Squamates are one of the largest groups of extant vertebrates. For many years, their systematics seemed to be well established, yet comprehensive molecular genetics analyses conducted in the XXI century suggest completely different picture of the squamate phylogeny. Traditional morphological data suggest that squamates comprise two main groups – iguanians and scleroglossans. However, molecular data imply that iguanians are deeply nested within Scleroglossa and most closely related to squamates of strikingly different morphology such as monitor lizards, slow worms and snakes. This would suggest a huge amount of convergence either in morphology or gene sequences between many groups of squamates and their closest relatives

Embryonic development and perinatal skeleton in a limbless, viviparous lizard, Anguis fragilis (Squamata: Anguimorpha)

Despite the long history of embryological studies of squamates, many groups of this huge clade have received only limited attention. One such understudied group is the anguimorphs, a clade comprising morphologically and ecologically very diverse lizards. We describe several stages of embryonic development of Anguis fragilis, a limbless, viviparous anguimorph. Interestingly, in several clutches we observe high morphological variation in characters traditionally important in classifying embryos into developmental stages. The causes of this variation remain unknown but environmental factors do not seem to be very important. Additionally, we describe the state of ossification in several perinatal specimens of A. fragilis. The cranial skeleton is relatively poorly ossified around the time of birth, with all of the bones constituting the braincase unfused. On the other hand, the vertebral column is well ossified, with the neurocentral sutures closed and the neural arches fused in all postatlantal vertebrae. Such an advanced state of ossification may be related to the greater importance of the vertebral column in locomotion in limbless species than in ones with fully-developed limbs. Numerous factors seem to affect the state of ossification at the time of hatching or birth in squamates, including phylogenetic position, mode of reproduction and, potentially, limblessness. However, data from a greater number of species are needed to reach firmer conclusions about the relative importance of these variables in certain clades

Evolution of developmental sequences in lepidosaurs

Background Lepidosaurs, a group including rhynchocephalians and squamates, are one of the major clades of extant vertebrates. Although there has been extensive phylogenetic work on this clade, its interrelationships are a matter of debate. Morphological and molecular data suggest very different relationships within squamates. Despite this, relatively few studies have assessed the utility of other types of data for inferring squamate phylogeny. Methods We used developmental sequences of 20 events in 29 species of lepidosaurs. These sequences were analysed using event-pairing and continuous analysis. They were transformed into cladistic characters and analysed in TNT. Ancestral state reconstructions were performed on two main phylogenetic hypotheses of squamates (morphological and molecular). Results Cladistic analyses conducted using characters generated by these methods do not resemble any previously published phylogeny. Ancestral state reconstructions are equally consistent with both morphological and molecular hypotheses of squamate phylogeny. Only several inferred heterochronic events are common to all methods and phylogenies. Discussion Results of the cladistic analyses, and the fact that reconstructions of heterochronic events show more similarities between certain methods rather than phylogenetic hypotheses, suggest that phylogenetic signal is at best weak in the studied developmental events. Possibly the developmental sequences analysed here evolve too quickly to recover deep divergences within Squamata

Morphology versus molecules - on the conflict between phylogenetic hypotheses in squamate reptiles

Łuskonośne to jedna z największych grup współczesnych kręgowców. Przez wiele lat jej systematyka wydawała się dobrze ustalona, jednak zaawansowane badania molekularne prowadzone w XXI wieku sugerują zupełnie odmienny jej obraz. Tradycyjne dane morfologiczne wskazują, że łuskonośne obejmują dwie główne grupy - Iguania i Scleroglossa. Z kolei według badań molekularnych Iguania są zagnieżdżone głęboko wewnątrz Scleroglossa i blisko spokrewnione z zupełnie odmiennymi morfologicznie waranami, padalcami, czy wężami. Wskazywałoby to na ogromną konwergencję w morfologii lub sekwencjach genów pomiędzy różnymi grupami łuskonośnych i ich krewnych.Squamates are one of the largest groups of extant vertebrates. For many years, their systematics seemed to be well established, yet comprehensive molecular genetics analyses conducted in the XXI century suggest completely different picture of the squamate phylogeny. Traditional morphological data suggest that squamates comprise two main groups - iguanians and scleroglossans. However, molecular data imply that iguanians are deeply nested within Scleroglossa and most closely related to squamates of strikingly different morphology such as monitor lizards, slow worms and snakes. This would suggest a huge amount of convergence either in morphology or gene sequences between many groups of squamates and their closest relatives

Variation in the Jaw Musculature of Ratsnakes and Their Allies (Serpentes: Colubridae)

Snakes have a highly modified feeding apparatus. However, its associated musculature is often poorly known. In order to study variation in the cephalic musculature, we dissected specimens representing 28 snake species belonging to the New World clade Lampropeltini and their Old World relatives. The observed variation was analysed using a phylogenetic framework. We found that the pattern of their musculature is conservative. We observed no interspecific variation in the intermandibular muscles or in the posterior jaw adductors. Variation within the dorsal constrictors and lateral jaw adductors is relatively low. This could be explained by morphological (space) limitations and functional constraints

Densitometric test in differential diagnosis of short stature children

The aim of the study is to compare the dimensions and optical density of the second metacarpal bone in children with short stature caused by idiopatic growth hormone deficiency (IGHD), and children with short stature, but normal level of growth hormone. The diagnostic importance of the obtained results is assessed

Body dimensions and proportions in the differential diagnosis of child growth retardation

Abstract This study was aimed at determining the similarities and differences with regard to body build traits between two groups of short-statured children: the first one including children with growth retardation related to the growth hormone deficiency and the second one comprising of children with normal secretion of the growth hormone. Subsequently the traits useful in the differential diagnostics of growth retardation were selected. Anthropometric measurements were taken from 273 short-statured non-treated children aged from 3 to 17 years (73 girls and 200 boys). The children were divided into 6 clinical groups on the basis of the clinical picture and the results of stimulation tests assessing the pituitary reserve for growth hormone secretion. The clinical groups were differentiated using a specifically developed anthropometric test based on 9 calendar age traits (height, weight, BMI, length of upper and lower limbs, trunk length, shoulders breadth, hips breadth and chest breadth) and 4 developmental age traits (length and circumference of the head, chest circumference, thigh circumference) and the calculated value of arm fat content and the average stature of the parents

Phylogenetic Diversity of Ossification Patterns in the Avian Vertebral Column: A Review and New Data from the Domestic Pigeon and Two Species of Grebes

Despite many decades of studies, our knowledge of skeletal development in birds is limited in many aspects. One of them is the development of the vertebral column. For many years it was widely believed that the column ossifies anteroposteriorly. However, later studies indicated that such a pattern is not universal in birds and in many groups the ossification starts in the thoracic rather than cervical region. Recent analyses suggest that two loci, located in the cervical and thoracic vertebrae, were ancestrally present in birds. However, the data on skeletal development are very scarce in the Neoaves, a clade that includes approximately 95% of extant species. We review the available information about the vertebral column development in birds and describe the ossification pattern in three neoavians, the domestic pigeon (Columba livia domestica), the great crested grebe (Podiceps cristatus) and the red-necked grebe (Podiceps grisegena). In P. cristatus, the vertebral column starts ossifying in the thoracic region. The second locus is present in the cervical vertebrae. In the pigeon, the cervical vertebrae ossify before the thoracics, but both the thoracic and cervical loci are present. Our ancestral state reconstructions confirm that both these loci were ancestrally present in birds, but the thoracic locus was later lost in psittacopasserans and at least some galloanserans