Iliac Blade Research Articles

A new basal archosauriform diapsid from the Lower Triassic of Argentina

ABSTRACT The best-known South American Early Triassic archosauriform belongs to a putative proterosuchid briefly reported by José Bonaparte in 1981, collected from the Quebrada de los Fósiles Formation (Puesto Viejo Group, Argentina). This specimen consists of well-preserved natural external molds of a partial postcranium that preserve dorsal vertebrae, osteoderms, a dorsal rib, a possible gastralium, a chevron, a humerus, an ilium, two metapodials, and an ungual. We re-describe this specimen and identify autapomorphies that allow us to recognize Koilamasuchus gonzalezdiazi, gen. et sp. nov. The presence of an iliac blade with a slightly convex dorsal margin and with a maximum length more than 3 times its maximum height places Koilamasuchus within Archosauriformes. A cladistic analysis of basal Archosauriformes positions Koilamasuchus more crownwards than Proterosuchus, Sarmatosuchus, Fugusuchus, and Osmolskina, as the sister taxon of the clade that includes Erythrosuchidae and Archosauria. Proterosuchidae is found to be paraphyletic. The presence of an iliac preacetabular process, a pubic peduncle that forms an angle lower than 45° to the longitudinal axis of the ilium, and dorsal body osteoderms positions Koilamasuchus in Archosauriformes more crownwards than proterosuchids. Koilamasuchus is more basal than erythrosuchids within Archosauriformes because of the presence of dorsal ribs with a poorly developed proximal end. Koilamasuchus importantly increases the diversity of Archosauriformes during the biotic recovery following the Permo-Triassic mass extinction.

Saltopus, a dinosauriform from the Upper Triassic of Scotland

ABSTRACTSaltopus elginensis, reported in 1910 from the yellow sandstones of the Lossiemouth Sandstone Formation (Late Triassic) of Morayshire, NE Scotland, has long been controversial. It was described first as a theropod dinosaur, but others disagreed. Reanalysis of the type, and only, specimen using casts from the natural rock moulds, as well as X-rays and CT scans, has revealed new anatomical data not available to previous researchers. Saltopus was a small, 800–1000 mm-long biped, whose tail made up more than half its length. It is an avemetatarsalian because it has elongated and tightly bunched metatarsals, the tibia is longer than the femur, the calcaneal tuber is rudimentary or absent, and metatarsal II is equal to or longer than metatarsal IV; a unique assemblage of characters diagnosing this clade. Saltopus is a dinosauromorph on the basis of the reduced fingers IV and V, the saddle-shaped dorsal margin of the iliac blade, and the articulation of sacral rib 1 close to the front of the iliac blade. Saltopus is a dinosauriform on the basis of the trochanteric shelf and lesser trochanter on the proximal end of the femur, the waisted sacral ribs, and perhaps the rod-like and straight pubis. However, it lacks all apomorphies of Dinosauria, retaining for example the primitive condition of two sacral vertebrae. Cladistic analyses place Saltopus within Dinosauromorpha and Dinosauriformes, and between the basal dinosauriform Pseudolagosuchus and the derived clade consisting of Silesauridae and Dinosauria, so making it one of a radiation of small pre-dinosaurian bipedal archosaurs in the Triassic found so far in North and South America and in Europe.

Shape differences in the bony pelvis of women with and without pelvic floor disorders

Pelvic floor disorders (PFDs) include a suite of urinary and gastrointestinal tract problems that have a negative impact a woman's quality of life and effect up to one‐third of women. Earlier studies focused on width of the pelvis as a risk factor for PFDs. This is the first study to address the association of complex 3D pelvic shape with PFDs. We hypothesize that insertion sites of the muscular pelvic diaphragm are displaced further from one another in women with PFDs relative to unaffected controls. This study uses 3D geometric morphometrics to analyze the bony pelvis in a clinical sample of women with (n=6) and without (n=11) PFDs. Landmarks (k=41) were collected on pelvic reconstructions from MR data. Generalized Procrustes Analysis (GPA) and Euclidean Distance Matrix Analysis (EDMA) were used to localize shape differences between the control group and the affected group.GPA analysis identified significant shape differences between the two groups (α<.05); relative to other landmarks, the sacrum and ischial spines move posteriorly, and the iliac blades move medially and superiorly in women with PFDs. EDMA analyses demonstrated that the majority of differences between groups included the posterior displacement of the sacrum and antero‐posterior elongation of the birth canal. These results suggest that the posterior elongation of the pelvic diaphragm may be a better predictor of risk for PFD than pelvic width alone.Grant Funding Source: none

A New Large-Bodied Theropod Dinosaur from the Middle Jurassic of Warwickshire, United Kingdom

Previously undocumented postcranial material from the Chipping Norton Limestone Formation (Middle Jurassic: Lower Bathonian) of Cross Hands Quarry, near Little Compton, Warwickshire represents a new large-bodied theropod dinosaur, distinct from the contemporaneous Megalosaurus bucklandii. Cruxicheiros newmanorum gen. et sp. nov. is diagnosed by a single autapomorphy, the presence of a proximomedially inclined ridge within the groove that marks the lateral extent of the posterior flange of the femoral caput (trochanteric fossa). C. newmanorum shows three tetanuran features: widely separated cervical zygapophyses, a swollen ridge on the lateral surface of the iliac blade and an anterior spur of the caudal neural spines. However, due to fragmentary preservation its affinities within Tetanurae remain uncertain: phylogenetic analysis places it as the most basal tetanuran, the most basal megalosauroid (= spinosauroid) or the most basal neotetanuran.

A new reconstruction of Sts 14 pelvis ( Australopithecus africanus) from computed tomography and three-dimensional modeling techniques

The purpose of this study is to propose a new reconstruction of the australopithecine Sts 14 pelvis from original fossils. Digital models created from CT images allow us to perform mirroring operations, select valid regions after digital interposition, and reassemble parts. The key-element of the reconstruction is the sacroiliac joint, restored from right and left articular surfaces, which places of the pubic symphysis close to the sagittal plane. The complete pelvis is obtained by 3D model mirroring of hip-bone and sacrum. The present reconstruction of the Sts 14 pelvis is consistent with Schmid's (1983) [Folia Primatol. 40, 283–306, 1983] and Häusler and Schmid's A.L. 288–1 [J. Hum. Evol. 29, 363–383, 1995] pelvic reconstructions by illustrating a relatively platypelloid shape of the pelvic cavity and laterally inclined iliac blades. The pelvic morphology suggests that australopithecines had a less posteriorly tilted sacrum in erect posture than modern humans. As compared with Lovejoy's [Am. J. Phys. Anthropol. Suppl. 50, 460, 1979] A.L. 288-1 pelvic reconstruction, the less transversely flattened shape of the Sts 14 pelvic cavity led to obstetrical mechanics characterized as in humans by ante-ischiatic birth and a curved trajectory. We deduce a human-like movement of rotation and flexion of the fetal skull in the Sts 14 pelvic cavity.

Osseous sarcoidosis masquerading as metastatic disease

A 64-year-old woman presented with suspected malignancy, characterized by unexplained weight loss of 2 stone over the preceding year, lethargy and widespread musculoskeletal and back pain for which she was taking Zomorph 10 mg twice daily. She was iron deficient; endoscopy and colonoscopy were unremarkable. A bone scan showed widespread increase in uptake of radioisotope (Figure 1). A computed tomography scan showed multiple lytic lesions throughout the thoracolumbar spine, ribs and iliac blades, consistent with metastatic disease (Figure 2). There was no evidence of cord compression. There were multiple soft tissue nodules throughout both lungs, in tandem with small volume mediastinal lymph node enlargement. Fine needle sampling of a small volume (7 mm) supraclavicular lymph node revealed no malignant cells but surprisingly the sample demonstrated well-formed non-caseating granulomata, staining negative for acid-fast bacilli. Serum angiotensin-converting enzyme levels were high (114 U/litre; normal range 16–53 U/litre), with a calcium level of 2.61 mmol/litre and normal creatinine levels. There was concern that the patient might have dual pathology and so a vertebral body was additionally biopsied, the result again showing a non-caseating granuloma compatible with sarcoid (Figure 3). The diagnosis was revised to systemic sarcoidosis with extensive bony involvement. Prednisolone and bisphosphonate were commenced. There was immediate symptomatic improvement, mirrored by declining serum angiotensin-converting enzyme levels. Interestingly, on commencing treatment there was an initial rapid rise in her alkaline phosphatase level (Figure 4), possibly related to increased bone turnover. At her 2-month review she was virtually free of symptoms. Repeat computed tomography of the chest showed marked regression of the pulmonary nodules but persistence of the skeletal lesions.

THE SKELETAL ANATOMY AND RELATIONSHIPS OF A NEW DISCOSAURISCID SEYMOURIAMORPH FROM THE LOWER PERMIAN OF MORAVIA (CZECH REPUBLIC)

A new genus and species of seymouriamorph tetrapod from the Lower Permian deposits of the Boskovice Furrow in Moravia (Czech Republic), Spinarerpeton brevicephalum, new genus, new species, is described in detail, and its cranial reconstruction and phylogenetic position within seymouriamorphs is presented. The skeletal anatomy of Spinarerpeton allows this new taxon to be assigned to the family Discosauriscidae (together with Discosauriscus Kuhn, 1933, Makowskia Klembara, 2005, and Ariekanerpeton Ivakhnenko, 1981). It is distinguished from other ?Uppermost Carboniferous-Lower Permian seymouriamorphs, Utegenia Kuznetsov and Ivachnenko, 1981, Ariekanerpeton, Discosauriscus, Makowskia, and Seymouria Broili, 1904, by the following characters: postorbital portion of skull short; postparietal and tabular abbreviated anteroposteriorly; posterior process of jugal long; squamosal high (posterior portion of cheek deep); basioccipital wide and with anteroposteriorly long bilateral processes; exoccipital high and with slender shaft; anterior margin of iliac blade running obliquely anteroventrally to posterodorsally. A phylogenetic analysis places Spinarerpeton as the sister taxon to the Lower Permian Makowskia within the Discosauriscidae.

A NEW TRAVERSODONTID CYNODONT (THERAPSIDA, EUCYNODONTIA) FROM THE MIDDLE TRIASSIC SANTA MARIA FORMATION OF RIO GRANDE DO SUL, BRAZIL

Abstract: Remains of a peculiar traversodontid cynodont, Protuberum cabralensis gen. et sp. nov., are described herein. The material was collected from two outcrops representing the Therapsid Cenozone (Middle Triassic) of the Santa Maria Formation, and consists of a cranium with most of its dentition preserved and an associated postcranial skeleton. The upper postcanines have two sharp cusps that are connected by a medial crest on unworn postcanines. The specimens possess several autapomorphies, including: (1) presence of thickened bone on the dorsal surface of the skull; (2) thick dorsal ribs, with remarkable processes situated on their dorsal borders that decrease in size distally; and (3) an iliac blade with a series of rugosities along its dorsal border. The lumbar ribs bear overlapping costal plates and have distally projecting rib shafts that differ from the pattern observed in Thrinaxodon, Pascualgnathus and Cynognathus.

A new Middle Triassic eosauropterygian (Reptilia, Sauropterygia) from southwestern China

ABSTRACT A new eosauropterygian genus and species is described from the middle Anisian (Middle Triassic) of Panxian (Guizhou Province, southwestern China). The new taxon is characterized by an unique specialization of the jaws that form an elongate pointed rostrum furnished with numerous small, monocuspid and vertically oriented teeth with a basally expanded crown and pointed tip, which is quite unlike any other sauropterygian known. Other diagnostic characters include: frontals paired; parietal unpaired; pineal foramen located centrally in broad parietal skull table; two carpal ossification; ilium with distinct preacetabular process at the base of the dorsally extending iliac blade; pubis plate-like and of rounded contours; two tarsal ossifications. The curved and distally expanded humerus, the reversed topological relationship of the clavicle and scapula, and the presence of three sacral ribs indicate sauropterygian affinities of the new taxon, whereas the ‘butterfly-shaped’ or ‘cruciform’ facet for the neural arch on the dorsal centrum surface indicate its eosauropterygian status.

Early evacuation of haematoma causing sciatic nerve compression: Yes or no? A comparative case report

A 68-year-old gentleman, Mr. GS, with a past medical history of Atrial Fibrillation (AF) and chronic renal disease (due to chronic glomerulonephritis) presented to a fracture clinic with a history of progressing foot drop and complete anaesthesia of the L4 to S1 dermatomes and dysthaesia to the surrounding dermatomes. He was on anti-hypertensive therapy in addition to warfarin for AF. A week previously the patient had been on holiday in Spain and had fallen. He complained of pain and swelling around the right iliac crest and was able to weight-bear almost immediately. Over the next 2 days the pain worsened and he noticed a weakness in dorsi-flexion of the foot and some numbness. A pelvic radiograph at the Emergency Dept. was taken which demonstrated a longitudinal fracture of the right iliac blade (Fig. 1). On arrival in orthopaedic clinic he mobilised with a frame and had an obvious foot drop. Examination revealed plantar flexion, dorsi-flexion and EHL function of just 1/5 (MMC scale). In addition the patient also had anaesthesia and pain in an L4 to S2 dermatomal distribution with brisk reflexes. After discussion with our radiology colleagues, an MRI of the hip, pelvis and lumbar spine was performed specifically to exclude nerve root avulsion injuries. The spine images were unremarkable, but the pelvic films showed amass suggestive of a haematoma (see Figs. 2 and 3). The imageswere sent to a specialist regional orthopaedic centre to rule out a sarcoma. Over the next 8 months, the patient’s neurological symptoms slowly improved, but there was some residual neurological deficit.

Erdheim‐Chester Disease With Cutaneous Features in an Indian Patient

A 60-year-old Indian woman presented with multiple asymptomatic, firm swellings over the face that had been progressively increasing for the past 3.5 years. She complained of dry cough and dyspnea of 2 years' duration, which was diagnosed as interstitial lung disease (ILD) based on chest radiography and high-resolution computed tomography. Apart from occasional backaches, the patient had no other systemic complaints. The results of the general physical examination was normal, with no lymphadenopathy. Cutaneous examination revealed multiple (5) firm, yellowish to skin-colored well-defined nodules with irregular margins ranging in size from 1 x 1 cm to 4 x 8 cm present over the left periorbital region and right jawline, with overlying telangiectasias on the skin (Figure 1). On examination of the chest, she had generalized rhonchi and crepts; the remainder of the systemic examination results were normal. Fine needle aspiration cytology from the nodule in the periorbital area revealed a dispersed population of spindle cells, numerous foam cells, and giant cells suggestive of xanthogranuloma. Histopathology from the nodule on the jawline showed abundant foamy histiocytes in the dermis with few multinucleated giant cells and lymphocytes (Figure 2). The foamy histiocytes were periodic acid-Schiff-positive. On immunohistochemistry, histiocytes were CD68-positive. Findings of routine investigations including hemogram, peripheral blood smear, and blood chemistry were normal. Radiography of the lumbosacral spine showed mixed osteolytic and osteosclerotic lesions involving L5-S1, the left sacroiliac joint, and the left iliac blade. Findings from radiography of the long bones and skull were normal. Contrast-enhanced computed tomographic scan of the abdomen and pelvis showed areas of osteolysis, with marginal sclerosis present bilaterally that involved the iliac blades and the right half of the sacrum. A methylene diphosphate bone scan revealed increased tracer uptake seen at the fifth lumbar vertebrae, bilateral sacroiliac bone, and left iliac bone and areas of photopenia in sacrum. Bone marrow aspiration from the sternum showed normal cells with a normal erythroid-to-myeloid ratio. Ultrasonographic B scanning of the eyes showed no retro-orbital involvement. Erdheim-Chester disease was diagnosed in this patient on the basis of diagnostic histopathology, radiologic features involving bones, and ILD and treatment with 40 mg oral prednisolone daily was started. Surgical debulking of her skin lesions was planned, but the patient refused due to her worsening ILD.

Taphonomic analysis of skeletal remains from chimpanzee hunts at Ngogo, Kibale National Park, Uganda

This study provides a taphonomic analysis of the largest known sample of bone fragments collected from chimpanzee hunts. The entire sample consists of 455 bone fragments from 57 chimpanzee hunting episodes of 65 prey individuals at Ngogo, Kibale National Park, Uganda. It has low taxonomic diversity, consisting overwhelmingly of primates, especially red colobus monkeys. The age distribution of the prey remains is skewed towards pre-adults. Cranial bones are the dominant element, followed by long bones. Axial postcranial elements have low survivorship, with a complete absence of pre-caudal vertebrae. Bone is damaged in distinct ways, such as: destruction of long bone ends, typically with intact but chewed shafts; fragmentation and compression cracking of crania; and preservation of only the iliac blades of the innominates. Tooth marks are present but uncommon (4.4% of total NISP). These analyses enable us to: 1) describe and characterize consistent patterns of bone damage inflicted by chimpanzees across a much larger prey sample than has been previously studied; 2) make a preliminary comparison of the generalized chimpanzee taphonomic signature to that of leopard and eagle consumption of primates, as well as modern human consumption of small mammals; and 3) assess the utility of such samples for recognition of early hominin small mammal carnivory. We present a model that may be useful for detecting a pre-technological hominin carnivory and suggest some fossil locales at which close inspection of cercopithecoid remains for the above patterns might reveal traces of hominin hunting, though we caution that a pre-technological hominin hunted “assemblage” is not likely to be archaeologically visible.

FUNCTIONAL AND EVOLUTIONARY ASPECTS OF THE POSTCRANIAL ANATOMY OF DICYNODONTS (SYNAPSIDA, THERAPSIDA)

Abstract: Restoration of the major skeletal muscles and functional morphological analysis of the postcranium were carried out on two Triassic dicynodont genera, Wadiasaurus and Lystrosaurus. A phylogenetic analysis of 12 selected Permian and Triassic dicynodont taxa was conducted and the postcranial character states were then mapped onto the most parsimonious tree. The analysis revealed changes in pectoral girdle and forelimb morphology, which included reduction of the coracoid plate, increasing robustness of the deltopectoral crest, change in humeral orientation from lateral to caudolateral, increasing prominence of the humeral head, and increasing robustness of the radius. Such changes can be associated with a functional tendency to reduce the lateral component of the propulsive force while still in an abducted mode. On the other hand, changes associated with the pelvic girdle included expansion of the preacetabular iliac process, reduction of the postacetabular iliac process, craniocaudal expansion of the iliac blade, change in the shape of the pubis from flat and plate‐like to small and rod‐like with a cranial process, and change in acetabular orientation from lateral to caudolateral. The femoral head, starting from a cranioproximal position, progressively became dorsally pronounced and offset from the body. Other features/changes associated with the femur included increasing robustness of the trochanter major, and increasing flattening of the femoral midshaft. Changes in the axial skeleton included increasing stiffening of the trunk to reduce lateral undulations, increasing dorsoventral flexion, and increasing sacral vertebral count, which can be correlated with the preacetabular iliac expansion. These findings suggest that the dicynodont postcranial skeleton evolved towards more upright hindlimb morphology with the body held well off the ground.

Diplocynodon muelleri comb. nov., an Oligocene diplocynodontine alligatoroid from Catalonia (Ebro Basin, Lleida Province, Spain)

ABSTRACT The study of more than 100 skeletal remains of Hispanochampsa muelleri Kälin, 1936, from the Oligocene of El Talladell (Lleida Province, Catalonia, Spain), has been decisive in revealing misinterpretations about its anatomy and phylogenetic position. Hispanochampsa muelleri is shown to be a member of the clade Diplocynodontinae, and is here considered a junior synonym of Diplocynodon. This analysis provides strong evidence for this monophyletic grouping, which is made up of the species Baryphracta deponiae, Diplocynodon darwini, Diplocynodon muelleri, D. tormis, D. ratelii, and D. hantoniensis. All of these species bear ventral osteoderms with paired ossifications, and a deep posterior tip of the iliac blade, which are synapomorphies of Diplocynodontinae. However, the interrelationships of the Diplocynodontinae remain unresolved. D. muelleri shares with D. hantoniensis, D. tormis, and D. ratelii the presence of an enlarged jugal foramen, and the particular dentary occlusion in line with the maxillary tooth row. It is highly likely that the two Spanish species, Diplocynodon muelleri and Diplocynodon tormis, were close relatives.

Three‐dimensional study of pelvic asymmetry on anatomical specimens and its clinical perspectives

The aim of this study was to assess pelvic asymmetry (i.e. to determine whether the right iliac bone and the right part of the sacrum are mirror images of the left), both quantitatively and qualitatively, using three-dimensional measurements. Pelvic symmetry was described osteologically using a common reference coordinate system for a large sample of pelvises. Landmarks were established on 12 anatomical specimens with an electromagnetic Fastrak system. Seventy-one paired variables were tested with a paired t-test and a non-parametric test (Wilcoxon). A Pearson correlation matrix between the right and left values of the same variable was applied exclusively to values that were significantly asymmetric in order to calculate a dimensionless asymmetry index, ABGi, for each variable. Fifteen variables were significantly asymmetric and correlated with the right vs. left sides for the following anatomical regions: sacrum, iliac blades, iliac width, acetabulum and the superior lunate surface of the acetabulum. ABGi values above a threshold of +/- 4.8% were considered significantly asymmetric in seven variables of the pelvic area. Total asymmetry involving the right and the left pelvis seems to follow a spiral path in the pelvis; in the upper part, the iliac blades rotate clockwise, and in the lower part, the pubic symphysis rotates anticlockwise. Thus, pelvic asymmetry may be evaluated in clinical examinations by measuring iliac crest orientation.

The seymouriamorph tetrapod Ariekanerpeton sigalovi from the Lower Permian of Tadzhikistan. Part II: Postcranial anatomy and relationships

ABSTRACTThe postcranial skeleton of Ariekanerpeton sigalovi (Seymouriamorpha: Discosauriscidae; Lower Permian, Tadzhikistan) differs from that of like-sized Discosauriscus specimens in showing: wider interclavicle anterior plate with smaller, rhomboidal sculptured field on its ventral surface not reaching plate posteromedial margins; broader interclavicle plate-stem junction; slightly narrower interclavicle posterior stem; anteroposteriorly narrower clavicle ventral plate with convex posterior margin; shorter, more robust humerus; four phalanges on fourth manus digit (five phalanges in Discosauriscus); ilium more elongate dorsoventrally with anteroposteriorly narrower neck; posterior process of iliac blade oriented distinctly posterodorsally rather than horizontally; more gracile atlantal rib; broadened distal end of second presacral rib. A revised cladistic analysis of the best known seymouriamorph species retrieves Ariekanerpeton either as sister group to both species of Discosauriscus, or to D. austriacus only.

Functional-adaptive analysis of the hindlimb anatomy of extant marsupials and the paleobiology of the Paleocene marsupials Mayulestes ferox and Pucadelphys andinus.

This article analyzes the adaptations of the hindlimb of two Early Paleocene marsupials, Mayulestes ferox and Pucadelphys andinus. This analysis is based on detailed comparisons with various extant marsupials, both South American and Australian. In the case of the South American opossums, original myological data were collected and osteological-myological associations were related to their locomotor behavior. The use of Australian genera helped to improve the appraisal of the locomotory habits of the fossil taxa. Several features are indicative of the ability of Mayulestes to climb or walk on uneven surfaces (e.g., very mobile hip joint, astragalocalcaneal joint pattern), and some other features emphasize a relative agility (e.g., strongly everted iliac blades, morphology of the distal epiphysis of the femur, medially stabilized cruroastragalar joint). Pucadelphys exhibits a hindlimb relatively similar morphologically to that of Mayulestes, but with features indicating slightly increased agility and a terrestrial component that is more emphasized than in Mayulestes. The Tiupampa fossils were therefore more agile than most living didelphids and resembled the condition observed in living dasyurids more. These conclusions complement a previous study performed on the forelimb of these fossils.

The tetrapod Caerorhachis bairdi Holmes and Carroll from the Lower Carboniferous of Scotland

ABSTRACTThe tetrapod Caerorhachis bairdi, probably from the Pendleian Limestone Coal Group in the Scottish Midland Valley, is rediagnosed and redescribed, and its affinities are discussed. Caerorachis was originally interpreted as a temnospondyl amphibian, based on characters that are now regarded as primitive for tetrapods, or of uncertain polarity. Several features of Caerorhachis (e.g. gastrocentrous vertebrae, curved trunk ribs, reduced dorsal iliac blade, L-shaped tarsal intermedium) are observed in certain primitive amniotes. In particular, Caerorhachis resembles ‘anthracosaurs’, generally considered to be among the most primitive of stem-group amniotes.The phylogenetic position of Caerorhachis is considered in the light of recently published cladistic analyses of Palaeozoic tetrapods. Most analyses place Caerorhachis at the base of, or within, ‘anthracosaurs’. When multiple, equally parsimonious solutions are found, its ‘anthracosaur’ affinities are shown in at least some trees, and are supported by several informative and, generally, highly consistent characters. Alternative phylogenetic placements (e.g. sister taxon to temnospondyls) are usually less well corroborated.If the fundamental evolutionary split of most early tetrapods into stem-group lissamphibians (e.g. temnospondyls) and stem-group amniotes (e.g. ‘anthracosaurs’) is accepted, then the revised interpretation of Caerprhachis sheds light on near-ancestral conditions for Amniota.

The osteology of Kotasaurus yamanpalliensis, a sauropod dinosaur from the Early Jurassic Kota Formation of India

ABSTRACT Extensive and well preserved sauropod material belonging to more than twelve individuals were recovered from the Early Jurassic Kota Formation of India. The sauropod Kotasaurus yamanpalliensis is characterized by simple dorsal vertebrae and a low iliac blade. Detailed osteological description of Kotasaurus is presented. The characters that distinguish Kotasaurus from the primitive sauropods are provided. It is considered to be one of the earliest sauropods and has some primitive features. The character analysis revealed that Kotasaurus is a basal sauropod in addition to Vulcanodon, Shunosaurus, Barapasaurus, and Omeisaurus.

The postcranial skeleton ofDiscosauriscusKuhn, a seymouriamorph tetrapod from the Lower Permian of the Boskovice Furrow (Czech Republic)

AbstractThe description of the postcranial skeleton of larval, metamorphic and early juvenile specimens of the genusDiscosauriscusis based on three-dimensional material and includes a description of the ontogeny of the swollen neural arches and the central elements of the vertebrae.Discosauriscushas 24 (or 23) presacral vertebrae. The morphology of the atlas–axis complex is similar to that inSeymouria sanjuanensis. The neural arches start to swell slightly in specimens of late larval stage; they are completely swollen immediately after metamorphosis. There are about 40 caudal vertebrae and one sacral vertebra. The atlantal pleurocentrum is paired in metamorphic individuals. In postmetamorphic individuals, the pleurocentra 2–5 are not completely closed dorsally; the pleurocentra 6–30 form complete discs. The first haemal arch is situated on the sixth caudal vertebra. The atlantal rib is present. There are six caudal ribs.Discosauriscushas an anocleithrum which is the first record of this dermal pectoral element within seymouriamorphs and Lower Permian tetrapods. The scapula and the coracoid are separate elements. The phalangeal formula of the manus is 2, 3, 4, 5, 3. The iliac blade has a massive, almost horizontally oriented posterior process; the anterior process is absent. The phalangeal formula of the pes is 2, 3, 4, 5, 3. Rounded ventral scales are present. The comparison and evaluation of the available postcranial elements ofDiscosauriscus, Utegenia, AriekanerpetonandSeymouriasupport the view thatDiscosauriscusandAriekanerpeton, forming the family Discosauriscidae, are immediately related genera.