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The primary goal of this study was to document the gross morphological and histological structure and histomorphometrical measurements of the intestines and digestive glands of ostrich (Struthio camelus) in relation to advancing age and sex. A total of 40 clinically healthy ostriches of either sex [(20 males, 20 females comprising of two age groups, viz, immature (1 month to 2.4 years) and adult (2.5 to 10 years)] of equal size were selected. Immediately after collection, morphological studies were carried out on all organs. Histological and histometrical studies were conducted on paraffin-embedded tissue sections with Image J® analysis software. Macroscopic parameters of the intestines, liver and pancreas invariably showed a rapid increase (P

Extant cassowaries (Casuarius) are unique flightless birds found in the tropics of Indo-Australia. They have garnered substantial attention from anatomists with focus centered on the bony makeup and function of their conspicuous cranial casques, located dorsally above the orbits and neurocranium. The osteological patterning of the casque has been formally described previously; however, there are differing interpretations between authors. These variable descriptions suggest that an anatomical understanding of casque anatomy and its constituent elements may be enhanced by developmental studies aimed at further elucidating this bizarre structure. In the present study, we clarify casque osteology of the southern cassowary (C. casuarius) by detailing casque anatomy across an extensive growth series for the first time. We used micro-computed tomography (μCT) imaging to visualize embryonic development and post-hatching ontogeny through adulthood. We also sampled closely related emus (Dromaius novaehollandiae) and ostriches (Struthio camelus) to provide valuable comparative context. We found that southern cassowary casques are comprised of three paired (i.e., nasals, lacrimals, frontals) and two unpaired elements (i.e., mesethmoid, median casque element). Although lacrimals have rarely been considered as casque elements, the contribution to the casque structure was evident in μCT images. The median casque element has often been cited as a portion of the mesethmoid. However, through comparisons between immature C. casuarius and D. novaehollandiae, we document the median casque element as a distinct unit from the mesethmoid.

The present study describes an almost complete cervical region of the fossil ostrich Struthio karatheodoris from the Turolian locality of Kerassia (Euboea, Greece). The material comes from two dist...

Pseudosuchians, archosaurian reptiles more closely related to crocodylians than to birds, exhibited high morphological diversity during the Triassic with numerous examples of morphological convergence described between Triassic pseudosuchians and post-Triassic dinosaurs. One example is the shuvosaurid Effigia okeeffeae which exhibits an "ostrich-like" bauplan comprising a gracile skeleton with edentulous jaws and large orbits, similar to ornithomimid dinosaurs and extant palaeognaths. This bauplan is regarded as an adaptation for herbivory, but this hypothesis assumes morphological convergence confers functional convergence, and has received little explicit testing. Here, we restore the skull morphology of Effigia, perform myological reconstructions, and apply finite element analysis to quantitatively investigate skull function. We also perform finite element analysis on the crania of the ornithomimid dinosaur Ornithomimus edmontonicus, the extant palaeognath Struthio camelus and the extant pseudosuchian Alligator mississippiensis to assess the degree of functional convergence with a taxon that exhibit "ostrich-like" bauplans and its closest extant relatives. We find that Effigia possesses a mosaic of mechanically strong and weak features, including a weak mandible that likely restricted feeding to the anterior portion of the jaws. We find limited functional convergence with Ornithomimus and Struthio and limited evidence of phylogenetic constraints with extant pseudosuchians. We infer that Effigia was a specialist herbivore that likely fed on softer plant material, a niche unique among the study taxa and potentially among contemporaneous Triassic herbivores. This study increases the known functional diversity of pseudosuchians and highlights that superficial morphological similarity between unrelated taxa does not always imply functional and ecological convergence.

Birds and crocodiles show radically different patterns of brain development, and it is of interest to compare these to determine the pattern of brain growth expected in dinosaurs. Here we provide atlases of 3D brain (endocast) reconstructions for Alligator mississippiensis (alligator) and Struthio camelus (ostrich) through ontogeny, prepared as digital restorations from CT scans of stained head and dry skull specimens. Our morphometric analysis confirms that ostrich brains do not change significantly in shape during postnatal growth, whereas alligator brains unfold from a cramped bird-like shape in the hatchling to an elongate, straight structure in the adult. We confirm that birds exhibit paedomorphic dinosaur endocranial traits such as retaining an enlarged and compact brain shape in the adult, whereas crocodiles show peramorphic traits where the brain elongates with growth as the skull elongates. These atlases of ontogenetic stages of modern bird and crocodilian endocrania provide a basis for comparison of non-avian dinosaur endocasts and consideration of the divergence of the "avian" and "crocodilian" modes of brain development and heterochronic change on phylogenies.

The avian lung is highly specialized and is both functionally and morphologically distinct 30 from that of their closest extant relatives, the crocodilians. It is highly partitioned, with a 31 unidirectionally ventilated and immobilized gas-exchanging lung, and functionally decoupled, 32 compliant, poorly vascularized ventilatory air-sacs. To understand the evolutionary history of 33 the archosaurian respiratory system, it is essential to determine which anatomical 34 characteristics are shared between birds and crocodilians and the role these shared traits play 35 in their respective respiratory biology. To begin to address this larger question, we examined 36 the anatomy of the lung and bronchial tree of ten American alligators (Alligator 37 mississippiensis) and eleven ostriches (Struthio camelus) across an ontogenetic series using 38 traditional and micro-computed tomography (µCT), three-dimensional (3D) digital models, and 39 morphometry. Intraspecific variation and left to right asymmetry were present in certain 40 aspects of the bronchial tree of both taxa but was particularly evident in the cardiac (medial) 41 region of the lungs of alligators and the caudal aspect of the bronchial tree in both species. The 42 cross-sectional area of the primary bronchus at the level of the major secondary airways and 43 cross-sectional area of ostia scaled either isometrically or negatively allometrically in alligators 44 and isometrically or positively allometrically in ostriches with respect to body mass. Of fifteen 45 lung metrics, five were significantly different between the alligator and ostrich, suggesting that 46 these aspects of the lung are more interspecifically plastic in archosaurs. One metric, the 47 distances between the carina and each of the major secondary airways, had minimal 48 intraspecific or ontogenetic variation in both alligators and ostriches, and thus may be a 49 conserved trait in both taxa. In contrast to previous descriptions, the 3D digital models and CT 50 scan data demonstrate that the pulmonary diverticula pneumatize the axial skeleton of the 51 ostrich directly from the gas-exchanging pulmonary tissues instead of the air sacs. Global and 52 specific comparisons between the bronchial topography of the alligator and ostrich reveal 53 multiple possible homologies, suggesting that certain structural aspects of the bronchial tree 54 are likely conserved across Archosauria, and may have been present in the ancestral 55 archosaurian lung.

The ostrich (Struthio camelus, Linnaeus 1758) is the largest bird in the world. It is of great economic importance in Africa and is found across several countries. With developments in breeding systems, morphological studies that facilitate the application of the knowledge are necessary, considering the species has unique anatomical features. The objective of the present study was to describe the major tributaries of the hepatic vein in the species. Ten viscera of adult individuals of both sexes, which were injected with Neoprene latex through the hepatic vein, were used to visualize their tributaries. After the vascular repletion, the tissues were fixed and conserved in 10% formaldehyde aqueous solution. The hepatic carrier system was dissected and photo-documented. The left hepatic vein receives blood from the proventricle and gastric ventricle, while the right hepatic vein is responsible for the drainage of blood into the following organs: spleen, through the proventriculosplenic vein; pancreas, through the pancreaticoduodenal vein; jejunum, through the jejunum trunk; and the colon, which forms the cranial mesenteric vein. Resumo O avestruz (Struthio camelus, Linnaeus 1758) é a maior ave do mundo, com uma importância comercial acentuada na África e expandindo-se para diversos países. Assim, com o desenvolvimento dos sistemas de criação, tornam-se necessários estudos morfológicos que subsidiem as áreas aplicadas, pois a espécie apresenta características anatômicas próprias. O objetivo deste estudo foi a descrição dos principais afluentes da veia porta-hepática nesta espécie. Para a realização do presente trabalho, foram utilizadas dez vísceras de animais adultos, de ambos os sexos, que foram injetados com Neoprene látex por meio da veia porta-hepática para evidenciar os seus afluentes. Após a repleção vascular, os animais foram fixados e conservados em solução aquosa de formaldeído a 10%. O sistema porta-hepático foi dissecado e fotodocumentado. Observou-se que a veia porta-hepática esquerda recebe sangue da região do proventrículo e ventrículo gástrico. A veia porta-hepática direita é a responsável pela drenagem do sangue nos seguintes órgãos: baço, por meio da veia proventriculoesplênica, pâncreas, pela veia pancreaticoduonais, jejuno, por meio do tronco jejunal, e o cólon, que forma a veia mesentérica cranial.

Lawsonia intracellularis is the causative agent of proliferative enteropathy (PE) in pigs, a disease of economic importance worldwide. The present study aimed to investigate the occurrence of L. intracellularis in ostriches using a sensitive and specific nested polymerase chain reaction (nested PCR). A total number of 112 fecal samples (64 healthy, 48 diarrheic) were collected from 11 ostrich farms located in four provinces in Iran (Semnan, Tehran, Gilan, Yazd). The results showed the presence of L. intracellularis in three diarrheic and four apparently healthy birds. The frequency of positive results was the same in both groups (6.25% healthy vs. 6.25% diarrheic). Although the results of this study did not reveal any relationship between this organism and diarrhea (P > 0.05), the molecular detection of L. intracellularis on a farm where birds were suffering from the typical clinical symptoms of PE highlights the need for evaluation of PE in ratites.

1. Sex-related differences of long pelvic limb bones and serum bone metabolism indices were evaluated in 14-month-old female (N = 7) and male (N = 7) ostriches of similar body weights. 2. Densitometric parameters of femur, tibia and tarsometatarsus were determined using quantitative computed tomography (volumetric bone mineral density, calcium hydroxyapatite density and mean volumetric bone mineral density) and dual energy X-ray absorptiometry (bone mineral density and bone mineral content) methods. Geometrical parameters such as cortical bone area, cross-sectional area, second moment of inertia, mean relative wall thickness and cortical index were determined in the midshaft of bones. Mechanical properties of bones (maximum elastic strength and ultimate strength) were evaluated using three-point bending test. Serum concentrations of free amino acids, osteocalcin, N-terminal propeptide of type I procollagen, C-terminal telopeptides of type II collagen and total antioxidative capacity were also determined. 3. Bone weight and relative bone weight of all bones were significantly higher in males than in females. Significantly lower values of trabecular bone mineral density and calcium hydroxyapatite density were found in the trabecular bone of tibia in males. The highest number of the sex-related differences was observed in the tarsometatarsus where bone length, bone mineral content, cortical bone area, cross-sectional area and ultimate strength were higher in males. Serum concentrations of taurine, hydroxyproline, valine and isoleucine were significantly higher in males. 4. Higher loading of the tarsometatarsus in comparison to femur and tibia may be an important factor interacting with sex hormones in regulation of bone formation and mineralisation processes. Sex-related differences of bone properties were associated with increased serum concentration of selected amino acids in males.

The aim of this study was to develop a detailed and accessible set of reference images of the normal radiographic anatomy of the digits of the ostrich (Struthio camelus), with emphasis on the metatarsophalangeal joint and its arthrography. The distal excised pelvic limbs of 10 normal ostriches of different ages (ranging from 10 to 365 days of age) obtained from an abattoir were radiographed, and 2 arthrograms were performed. To illustrate the normal radiographic anatomy of the tarsometatarsal bone, 39 images were selected, labelled, and presented along with detailed descriptions and corresponding images of the bony skeleton. These results provide a valuable dataset to assist in understanding the normal anatomy of the ostrich metatarsophalangeal joint and digits and allow comparison of abnormal corresponding structures in clinical cases in ostriches.

A specialized region of the bill tip characterized by a complex arrangement of mechanoreceptors and referred to as a bill tip organ, has been identified in numerous avians. A bill tip organ was initially inferred in kiwi species by the presence of numerous, bony pits in the rostrum of the bill, and later confirmed histologically. This study enumerates and compares the number and distribution of pits present in the bill tip in the ostrich and emu. The heads from 10 ostrich and 5 emu were prepared for osteological examination. The pattern and total number of pits was similar between the two species. However, the ostrich had significantly more pits in the regions underlying the Culmen and Gonys, whereas the emu displayed significantly more pits in the dorsal part of the mandibular rostrum. The relatively even distribution of pits in the inner and outer surfaces of both the mandibular and maxillary rostra suggest that the bill tip of the ostrich and emu are equally sensitive externally and intra-orally, as opposed to probing birds, where the major concentration of pits is located on the outer surfaces of the bill tips. The presence of pits in the bill tips of extant paleaognaths may be of relevance in interpreting the pits in the rostra of extinct therapod dinosaurs. The presence of bony pits in a region which is also well supplied with sensory nerves is highly suggestive of a bill tip organ in the ostrich and emu and which needs to be confirmed histologically. Anat Rec, 300:1705-1715, 2017. © 2017 Wiley Periodicals, Inc.

Ostrich (Struthio camelus) is a species belonging to the Struthionidae family of Struthioniformes order that does not have the flying ability among birds. The aim of this study was to make a subgross investigation on anatomical structures of middle ear in ostrich and to determine the morphometry of the columella. In the present study, 4 adult ostrich heads were used in the study. Tympanic cavity and the formations inside are removed from the skull by protecting the cranial roof. Subgross examinations of tympanic cavity, columella and other anatomic structures were then performed, and morphometric measurements of columella and some anatomical structures were performed using a digital calliper.It was determined that tympanic cavity, surrounded by ear capsule (os oticum), had a conical shape and was covered with mucosa that was tightly adjacent to the periosteum. Tympanic membrane, columella and osteochondral structures, ligaments, a branch of external ophthalmic artery and the presence of chorda tympani were detected in tympanic cavity. It was observed that columella was placed diagonally in tympanic cavity. The vestibular (proximal) end having a circular shape was found to have a large basis and annular ligament which ended up with thickened, small columns. Finally, we demonstrated anatomy and morphometric values of middle ear in ostrich. The anatomy and formations of the middle ear are clearly shown. It can be asserted that anatomical formations in the middle ear of an ostrich are similar to other birds.

A recently discovered articulated partial skeleton of Ornithomimus from the Upper Cretaceous Dinosaur Park Formation of Alberta, Canada is remarkable in the extent and quality of preservation of integumentary structures including feathers. It is the first ornithomimid to preserve a tail bearing extensive plumaceous feathers that are slightly more elongate in comparison to those present on the remainder of the body. However, the underside of the tail and the hind limb distal to the middle of the femur appear devoid of plumage. Overall, the plumage pattern in Ornithomimus is similar to that of Struthio camelus (ostrich) and other large palaeognaths, indicating a probable function in thermoregulation. The specimen also preserves the body outline around the legs, including a skin contour anterior to the femur, analogous to skin webs in extant birds. Whereas the knee web of birds bridges the knee to the abdomen, in Ornithomimus it spans from the mid-femoral shaft to the abdomen, and is herein referred to as an anterior femoral web. This is the first report of such soft tissue structures in non-avian theropods. It may indicate that the resting position of the femur was positioned more anteroventrally in ornithomimids than in most theropods, and in that sense may have been transitional to the situation in modern birds.

The hyoid bone of the ostrich was divided into two parts; basihyoid and horns. The basihyoid consisted of three components; paraglossal, basihayle and urohyale. The paraglossal was unpaired,lay within the tongue parenchyma.On the other hand; the basihaylewas flat and octagonalcontinuing caudally by urohyale, which was stick like, compressed laterally.It reached at the first six trachea ringslevel. On the other hand, the horns included two pairs: ceratobranchiale and epibranchiale. The ceratobranchiale horn was ossified, concave and the longest one. It had bulges extremities for articulates with the basihayle proximally and epibranchiale horn distally, while the epibranchiale horn was cartilagenous structure, shorter than the ceratobranchiale and its end was tapered. The hyoid bone of the ostrich was firmly attached to the tongue, larynx,trachea and the cervical muscculature tissue and all underlying structures by the connective tissue.

The ostrich is the largest living bird and has unique characteristics in its locomotor system that differentiate it from other bird species. The purpose of this study was to provide a reference atlas of reference-interval computed tomography (CT) and cross-sectional anatomy of the tarsometatarsal region and digits in the ostrich (Struthio camelus). The pelvic limbs of 25 ostriches were used for this imaging study. The transverse CT images were obtained from the middle third of the tarsometatarsal bone to the distal end of the third digit. The specimens were frozen and sectioned with an electric band saw at 1.5-2 cm intervals. The CT images were compared with the corresponding frozen cross sections. The bones, ligaments, and tendons were identified and labeled at each 1.5-2 cm intervals. The CT images provided anatomic details of the tendons and ligaments in the tarsometatarsal region and digits of the ostrich. The transverse CT images provided an excellent depiction of the anatomic structures of the leg and foot when compared with the corresponding frozen cross sections. The information presented in this study may be used as an initial reference when evaluating the CT images of an ostrich's tarsometatarsal region and digits. Moreover, the information provided in this report may be helpful in determining definitive diagnoses of musculoskeletal disorders affecting the lower leg in this species.

This study, facilitated by the use of immunohistochemistry, indicated the presence of taste buds in Dromaius novaehollandiae but not in Struthio camelus. Seen at the light microscope level, the taste buds consisted of follicular cells and receptor cells. The follicular cells were located at the periphery of the taste bud, essentially encapsulating the receptor cells. Two morphologically distinct receptor cells were identified. Immunohistochemical labelling for neurofilament identified gustatory nerves within the taste bud. The distribution of taste buds in D. novaehollandiae matched strategic locations in the oropharynx along which food could be sampled, according to the feeding method described for these birds. Future feeding studies would be necessary in D. novaehollandiae to determine the importance of taste discrimination in their diet. This study represents the first confirmed report of a sense of taste in any ratite species.

Avian eggshells serve the dual purposes of protecting the developing embryo from the external environment while also facilitating the loss of water vapor and the required exchange of CO2 and O2 gases. Pores that span the eggshell enable the loss of water and trans-shell gas exchange. Although knowledge of the geometry of these spaces is necessary to generate accurate estimates of the rate of gas diffusion across the shell, few techniques exist to obtain these data. Estimates of gas conductance across eggshells are typically calculated from eggshell thickness and the size and number of the pores on the exterior eggshell surface; the trans-shell pore spaces are assumed to be cylindrical in shape. To enable the testing of this assumption, we devised a novel method to visualize the three-dimensional morphology of eggshell pores using PU4ii, a polyurethane-based resin. Casts of the pores of eggshells of the domestic chicken (Gallus gallus )a nd House Sparrow (Passer domesticus) were unbranched and varied in diameter throughout their length, while casts of the pores of eggshells of the Ostrich (Struthio camelus) revealed a complex network of interconnected spaces. The simplicity of this technique and the stability and resilience of the resulting casts provide opportunities to predict gas flux across the shell and to evaluate the morphology of eggshell pores among birds from different taxonomic groups.

The objective of this study was to investigate the morphological features of the proventriculus of African ostrich (Struthio camelus). The location, appearance, and histological characteristics of the proventriculus were observed on postnatal day 90. The entire proventriculus had the appearance of a distensible sac; and exhibited a large number of glands. Under light microscope, the proventriculus wall was composed of mucosa, submucosa, muscular layer and adventitia. The mucosa was further divided into the lamina epithelialis, lamina propria, and muscularis mucosae. The submucosa was relatively thick and contained compound tubular glands having oxynticopeptic cells, mucous cells, and endocrine cells. These features of the proventriculus are possibly related to the dietary habits of the African ostrich, and they imply that this specie has a strong ability to digest and absorb food.

Flexor tendons function as energy storage and shock absorption structures in the tarsometatarso-phalangeal joint (TMTPJ) of ostrich feet during high-speed and heavy-load locomotion. In this study, mechanisms underlying the energy storage and shock absorption of three flexor tendons of the third toe were studied using histology and scanning electron microscopy (SEM). Macroscopic and microscopic structures of the flexor tendons in different positions of TMTPJ were analyzed. Histological slices showed collagen fiber bundles of all flexor tendons in the middle TMTPJ were arranged in a linear-type, but in the proximal and distal TMTPJ, a wavy-type arrangement was found in the tendon of the M. flexor digitorum longus and tendon of the M. flexor perforans et perforatus digiti III, while no regular-type was found in the tendon of the M. flexor perforatus digiti III. SEM showed that the collagen fiber bundles of flexor tendons were arranged in a hierarchically staggered way (horizontally linear-type and vertically linear-type). Linear-type and wavy-type both existed in the proximal TMTPJ for the collagen fiber bundles of the tendon of the M. flexor perforatus digiti III, but only the linear-type was found in the distal TMTPJ. A number of fibrils were distributed among the collagen fiber bundles, which were likely effective in connection, force transmission and other functions. The morphology and arrangement of collagen fiber bundles were closely related to the tendon functions. We present interpretations of the biological functions in different positions and types of the tendons in the TMTPJ of the ostrich feet.

The columella auris of the ostrich is derived as in the crocodile from three sources; the two upper segments of the hyoid arch (pharyngohyal and epihyal) and a laterohyal component. The latter contributes the homologue of the crocodilian suprastapedial (or lacertilian intercalary) as well as the tympanic process and the material of the lateral limb (which is not lacking as stated in the literature) of the lateral prong (supracolumellar arcade). Conditions in Struthio camelus confirm the views expressed by the authors in their paper on Crocodilus niloticus regarding the homologies of the columellar processes. The avian infracolumellar process represents the crocodilian infrastapedial plus the interhyal which in addition to primary arch material, includes a secondary subepidermal part. The ceratohyal (usually called stylohyal in the literature) remains attached to the columella through the infracolumellar process.

The distribution of Herbst corpuscles in the oropharynx of the ostrich and emu has recently been documented. However, although the morphology of these mechanoreceptors is well known in neognathous birds, little structural information is available on the Herbst corpuscles of ratites. Tissue sections from those regions of the oropharynx known to possess a high concentration of Herbst corpuscles were sampled from ostrich and emu heads collected after slaughter and prepared for light and transmission electron microscopy. Intra-oral Herbst corpuscles in the ostrich and emu displayed the same basic components (capsule, outer zone, inner core and axon) described in neognathous birds. However, some important differences were observed, notably, the presence of myofibroblasts in the capsule, sensory cilia in cells of the outer layers, a relatively larger, less organized outer zone and narrower inner core, and variations in the shape of the axon. The previously unreported presence of myofibroblasts in the capsule possibly indicates its ability to contract, thus altering the tension of the capsule, which in turn has implications for the conduction of vibrational stimuli. The sensory cilia in the myofibroblasts of the capsule bordering the outer zone, and in the fibroblasts of the outer zone itself, may play a regulatory role in controlling the contraction of the capsule. Such a function has not previously been reported for Herbst corpuscles in any species of bird. Anat Rec, 298:783–796, 2015. © 2014 Wiley Periodicals, Inc.

Commercial ostrich farming is constrained by the absence of a formal animal recording and evaluation scheme as well as by current farming practices. Artificial insemination may have an important role in overcoming these limitations, but requires a thorough knowledge of sperm morphology. Although the morphological characteristics of normal ostrich sperm have been documented, little information is available on the incidence and structural peculiarities of defective sperm in this species. Semen smears were prepared from the ejaculates of five ostriches (Struthio camelus), stained and evaluated. Defects were observed in 17% of sperm studied. Tail defects constituted the most common anomaly. Various forms of bending were the main tail defect, ranging from gentle to acute bends of the principal piece, Dag-like coiling at the head base, sharp reflexes of the midpiece as well as coiling of the endpiece. In contrast, head defects were comparatively low in frequency, with macrocephalic sperm being the defect most frequently observed in this region. Bent, microcephalic, acephalic and round sperm heads were also noted but were few in number. Cytoplasmic droplets occurred frequently in the fixed smears, either associated with the sperm or as free-lying droplets. A small percentage of sperm with multiple defects was recorded. The incidence of morphologically normal sperm in ostrich semen compared favorably with that reported in emu semen, another commercially farmed ratite. However, the range of defects differed appreciably between the two species. Sperm tail anomalies were the most frequent category in the ostrich, whereas head defects comprised the main grouping in the emu.

The subdivisions of the trigeminal nerve (N. ophthalmicus R. medialis and N. intramandibularis) innervating the upper and lower bill tip, respectively, were well developed in both the ostrich and emu and displayed extensive branching. Transmission electron microscopy revealed that both nerves displayed features typical of a mixed, peripheral nerve. Nerve fibre size in the ostrich and emu was larger than that reported in domestic poultry. There were a significantly higher number of myelinated nerve fibres in the N. ophthalmicus R. medialis in the emu by comparison with the same nerve in the ostrich, or by comparison with the N. intramandibularis of either species. As myelinated nerve fibres supply Herbst corpuscles, and these structures have been demonstrated in this region in these two species, this may indicate that the upper bill of the emu is more sensitive to vibrational stimuli than the upper bill of the ostrich or the lower bill of both species. The large size of the nerve fibres, the high nerve fibre count and the particular distribution of the nerves in the bill tip support the existence of a well-developed sensory area in this region of the ostrich and emu.

Herbst corpuscles are widely distributed throughout the oropharynx of the ostrich and emu in contrast to the general situation in birds. Knowledge of the comparative distribution of Herbst corpuscles in the oropharynx of these two commercially important ratite species may assist in a better understanding of their feeding habits. Tissue sections representing all parts of the oropharynx of five ostrich and five emu heads collected after slaughter were prepared for light microscopy, the Herbst corpuscles counted, and the relative percentage of corpuscles calculated for defined anatomical regions. Herbst corpuscles were more widespread in the oropharynx of the emu (where they were additionally found in the tongue and laryngeal mound) than in the ostrich but were absent from the pharyngeal folds in both species. The results further indicated that Herbst corpuscles were strategically located to aid in the handling and transport of food. In this context, the high concentration of Herbst corpuscles in the prominent median palatine and ventral ridges in the ostrich denote these structures as sensory organs, namely the palatal and interramal organs. The presence of these sensory organs, coupled with the higher relative percentage of Herbst corpuscles located on the rostral oropharyngeal floor, indicate that the part of the oropharynx caudal to the mandibular and maxillary rostra forms an important sensory region in the ostrich. Additionally, species-specific concentrations of Herbst corpuscles within the oropharynx were identified which appear to assist in the accurate positioning of the tongue and laryngeal mound for cleaning the choana (internal nares) after swallowing.

1. Early development of ostrich embryos was investigated in relation to time of egg collection and genotype. 2. A total of 321 ostrich eggs were collected during the 2008 and 2009 breeding seasons and the development of the embryo for up to the first 168 h of incubation was described and analysed. A sample of the incubated eggs was weighed and opened daily to investigate developmental changes. 3. In fresh eggs, the blastoderm contained a round, translucent dark area pellucida (AP) in the centre, with a surrounding thin white ring, likely to be the beginning of the area opaca (AO). Fresh eggs were considered infertile if the blastoderm was absent and instead numerous white droplets were present surrounded by vacuoles. 4. The average blastoderm area of a fresh fertile egg was 15.8 mm2, increasing to 143.3 mm2 after 2 d of incubation. By 72 h of incubation the area vasculosa (AV) was discernible in the posterior half of the blastoderm. 5. At 48 h of incubation the blastoderm area in eggs from the South African Black genotype (SAB) × Zimbabwean Blue genotype (ZB) crosses (104.5 ± 18.6 mm2) was lower than the pure SAB (141.0 ± 10.5 mm2), ZB (161.7 ± 13.5 mm2) and ZB × SAB crosses (166.1 ± 14.2 mm2). 6. Embryo length was 5.01 mm after 72 h of incubation and 14.5 mm after 168 h of incubation. At 168 h of incubation AV lengths for both ZB × SAB (53.2 mm) and SAB × ZB crosses (54.1 mm) were longer than in embryos from the pure breeds. 7. Results from this study can be put to practical use when determining whether eggs are infertile or fertile and also in investigating the age of early embryonic mortalities.

Morphological features of a collection of unknown-age wild kiwi (Apteryx mantelli) embryos from early development to point of hatch are described. Using these features, we assign developmental stages to each embryo and compare the progress of development to similar-staged ostrich (Struthio camelus) and chicken (Gallus gallus) embryos. Two ageing schemes for the kiwi embryos are developed by comparing measurements of their hindlimb segments, bills and crown–rump lengths with those of ostrich and chicken embryos at various stages of development. One of the 20 kiwi embryos was of known age. Both the ostrich model and the chicken model gave identical predictions for the marker and four other embryos. Developmental timing of some features differed between all three species, most markedly in the bill, with growth in the kiwi bill being relatively faster to achieve its larger relative and absolute size at hatch.

The Ostrich is a native bird of Africa, and is highly accomplished in terrestrial locomotion in desert and grassland environments. The foot is an important segment in the ostrich body, critical for damping vibration, absorbing energy, and maintaining balance; however, detailed information on the ostrich foot is sparse. In this study, the gross anatomy of locomotor system of the ostrich foot was investigated using dissection and medical scan modeling. The paper contains a detailed study of the organizational structure and relative positional relationship of bones, tendons, and ligaments, which can be used for further three-dimensional (3D) reconstruction, providing a solid foundation for the research of high speed, heavy load, and shock absorption mechanisms. The study also provides a theoretical basis for the research of robot travelling mechanisms and vehicles traversing desert or planetary terrain.

Background The ostrich Struthio camelus reaches the highest speeds of any extant biped, and has been an extraordinary subject for studies of soft-tissue anatomy and dynamics of locomotion. An elongate tarsometatarsus in adult ostriches contributes to their speed. The internal osteology of the tarsometatarsus, and its mechanical response to forces of running, are potentially revealing about ostrich foot function. Methods/Principal Findings Computed tomography (CT) reveals anatomy and bone densities in tarsometatarsi of an adult and a young juvenile ostrich. A finite element (FE) model for the adult was constructed with properties of compact and cancellous bone where these respective tissues predominate in the original specimen. The model was subjected to a quasi-static analysis under the midstance ground reaction and muscular forces of a fast run. Anatomy–Metatarsals are divided proximally and distally and unify around a single internal cavity in most adult tarsometatarsus shafts, but the juvenile retains an internal three-part division of metatarsals throughout the element. The juvenile has a sparsely ossified hypotarsus for insertion of the m. fibularis longus, as part of a proximally separate third metatarsal. Bone is denser in all regions of the adult tarsometatarsus, with cancellous bone concentrated at proximal and distal articulations, and highly dense compact bone throughout the shaft. Biomechanics–FE simulations show stress and strain are much greater at midshaft than at force applications, suggesting that shaft bending is the most important stressor of the tarsometatarsus. Contraction of digital flexors, inducing a posterior force at the TMT distal condyles, likely reduces buildup of tensile stresses in the bone by inducing compression at these locations, and counteracts bending loads. Safety factors are high for von Mises stress, consistent with faster running speeds known for ostriches. Conclusions/Significance High safety factors suggest that bone densities and anatomy of the ostrich tarsometatarsus confer strength for selectively critical activities, such as fleeing and kicking predators. Anatomical results and FE modeling of the ostrich tarsometatarsus are a useful baseline for testing the structure’s capabilities and constraints for locomotion, through ontogeny and the full step cycle. With this foundation, future analyses can incorporate behaviorally realistic strain rates and distal joint forces, experimental validation, and proximal elements of the ostrich hind limb.

SUMMARY Recent studies have presented range of motion (ROM) data in degrees for dinosaur forelimb joints, usually via physical manipulation of one individual. Using these data, researchers have inferred limb orientations, postures, gaits, ecological functions and even phylogenetic trends within clades. However, important areas of concern remain unaddressed; for example, how does ROM at a forelimb joint change after soft tissues are lost in archosaurs? And are fossil ROM methodologies amenable to reproducibility and statistical analysis? Here, we investigated these questions using the extant phylogenetic bracket of dinosaurs. Repeated measures of elbow joint ROM from Struthio camelus and Alligator mississippiensis forelimbs were statistically analyzed as they were sequentially dissected through five levels of tissue removal treatment. Our data indicate that there are no statistically significant differences in repeated measures of ROM between observers who use the same techniques. Extrinsic soft tissues, such as integument, muscles and ligaments were found to impede ROM at the elbow joint. Intrinsic soft tissues, such as articular cartilage, may increase ROM. The hypothesis that the articular surfaces of the bones within the elbow joints of archosaurs provide a general approximation of mobility is supported. Final ROMs were less than the initial ROMs in both taxa, which suggests that prior reports of elbow joint ROMs in degrees for nonavian dinosaurs may represent conservative estimates. We conclude that if observer bias and other variables are controlled for, ROM studies of fossil archosaur limbs can obtain useful degree data for inferring joint mobility in vivo.

This study was performed to obtain information on yolk utilization in fasted and fed ostrich chicks posthatching. The fasted trial lasted for 7 d, whereas the fed trial continued for 16 d. Fasted ostrich chicks showed a decrease of 31.3 g of BW, with yolk weight decreasing by 28.9 g daily after hatching. Yolk weight comprised 28% of 1-d-old ostrich chick BW and decreased to 12% at 7 d of age. Only 44.4% of the fasted ostrich chick yolk was assimilated over the trial period. Crude protein content of the yolk decreased by 13.2 g daily. Fat content increased by 1.77% daily, whereas total yolk fat weight decreased with 8.91 g daily. Slaughter weight of fed ostrich chicks increased, with yolk weight decreasing by 16.3 g daily. Yolk content for fed ostrich chicks was 26% of BW at 2 d of age. Ostrich chicks absorb 30% of yolk over the first 4 d, 67% after 8 d, and only deplete the yolk after 14 d posthatch. Fasted ostrich chicks absorbed the yolk content at a rate of 28.9 g/d, compared with 22.3 g/d over the first 8 d and 16.3 g/d over the 16 d for fed ostrich chicks. The CP content of the yolk decreased by 6.84 g daily in fed ostrich chicks, whereas fat content of the yolk increased by 1.39% daily, although total yolk fat weight decreased by 6.61 g daily. Yolk weight and total CP decreased faster over the first 7 d in the fasted ostrich chicks compared with the fed ostrich chicks, which indicated that the decrease in yolk weight could be attributed to absorption of protein from the yolk. Fat content decreased faster over the first 8 d from the yolk of the fed ostrich chicks compared with that from the yolk of the fasted ostrich chicks, which could indicate that external feed has a positive influence on the absorption of fat from the yolk content.

The erection mechanism of the penis in most vertebrates is blood vascular. A major evolutionary transition occurred in birds, where the erection mechanism changed from blood vascular to lymphatic. Within birds, however, the erection mechanism of the ratite penis has remained unknown. Early work suggested that the erection mechanism in ostrich Struthio camelus was blood vascular while no description existed for the emu Dromaius novaehollandiae or the rhea Rhea americana. Because the penis in all other described birds has a lymphatic erection mechanism, clarifying that the erection mechanism of ratites is of great importance to understanding one of the major evolutionary transitions of penis morphology within amniotes. Here, we show that the erection mechanism of ratites is lymphatic, confirming that the evolutionary transition to lymphatic erection occurred in the last common ancestor of Aves.

The ostrich foot has four digital pads, two on the 3rd digit, one on the 4th digit and one at metatarsophalangeal joint. Although these footpads are essential for long distance locomotion of the ostrich, no published data is available on the structure of these footpads. Therefore, the aim of this study is to examine the histo-morphological structure of these footpads in an attempt to highlight their structural functional adaptation for long distance motion. Morphologically, the ventral surface of each footpad is covered by numerous papillae which are varied in direction, length and thickness. In histological examination, the epidermis of the footpad consists of outer stratum corneum and inner stratum germinativum (which is subdivided into basal, intermediate and transitional layers). The stratum corneum has several layers of flattened horney cells. The nuclei of the basal cells have several mitotic figures. The cytoplasm of the stratum germinativum cells has multiple lipid droplets and multigranular bodies (in transitional cells only). Using scanning electron microscope, the collagen fibers in the mid and deep dermis of the footpad run parallel and connect to each other by very thin fibrils which are branched, crossed with each other in an oblique direction. Such arrangement of these collagen fibers and thin fibrils and presence of digital cushion are likely to be responsible for absorption of concussion and hence acceleration of the ostrich movement. We have concluded that ostrich footpads have unique modified structures which are adapted for long distance movement and protection of the underlying soft tissues.

The spleen structurally and functionally belongs to the hematopoietic organs and is also an important component of the reticuloendothelial system, which is known to play a major role in host defense. The histological structure of the spleen was investigated in the ostrich, a non-flying bird, the kestrel, a raptor, and the osprey, a fish-eating bird of prey (fish eagle). For this purpose, Mallory's modified triple stain, methyl green-pyronin and silver stain were used. Germinal centers were not present in the spleen of the osprey. In the spleen of the kestrel, penicillar arterioles and the surrounding lymphoid tissue were markedly dense. Compared to the other two birds, the red and white pulps were clearly distinguishable in the spleen of the ostrich.

In nonavian dinosaur long bones, the once-living chondroepiphysis (joint surface) overlay a now-fossilized calcified cartilage zone. Although the shape of this zone is used to infer nonavian dinosaur locomotion, it remains unclear how much it reflects chondroepiphysis shape. We tested the hypothesis that calcified cartilage shape reflects the overlying chondroepiphysis in extant archosaurs. Long bones with intact epiphyses from American alligators (Alligator mississippiensis), helmeted guinea fowl (Numida meleagris), and juvenile ostriches (Struthio camelus) were measured and digitized for geometric morphometric (GM) analyses before and after chondroepiphysis removal. Removal of the chondroepiphysis resulted in significant element truncation in all examined taxa, but the amount of truncation decreased with increasing size. GM analyses revealed that Alligator show significant differences between chondroepiphysis shape and the calcified cartilage zone in the humerus, but display nonsignificant differences in femora of large individuals. In Numida, GM analysis shows significant shape differences in juvenile humeri, but humeri of adults and the femora of all guinea fowl show no significant shape difference. The juvenile Struthio sample showed significant differences in both long bones, which diminish with increasing size, a pattern confirmed with magnetic resonance imaging scans in an adult. Our data suggest that differences in extant archosaur long bone shape are greater in elements not utilized in locomotion and related stress-inducing activities. Based on our data, we propose tentative ranges of error for nonavian dinosaur long bone dimensional measurements. We also predict that calcified cartilage shape in adult, stress-bearing nonavian dinosaur long bones grossly reflects chondroepiphysis shape.

Finite element (FE) analysis is becoming a frequently used tool for exploring the craniofacial biomechanics of extant and extinct vertebrates. Crucial to the application of the FE analysis is the knowledge of how well FE results replicate reality. Here I present a study investigating how accurately FE models can predict experimentally derived strain in the mandible of the ostrich Struthio camelus, when both the model and the jaw are subject to identical conditions in an in-vitro loading environment. Three isolated ostrich mandibles were loaded hydraulically at the beak tip with forces similar to those measured during force transducer pecking experiments. Strains were recorded at four gauge sites at the dorsal and ventral dentary, and medial and lateral surangular. Specimen-specific FE models were created from computed tomography scans of each ostrich and loaded in an identical fashion as in the in-vitro test. The results show that the strain magnitudes, orientation, patterns and maximum : minimum principal strain ratios are predicted very closely at the dentary gauge sites, even though the FE models have isotropic and homogeneous material properties and solid internal geometry. Although the strain magnitudes are predicted at the postdentary sites, the strain orientations and ratios are inaccurate. This mismatch between the dentary and postdentary predictions may be due to the presence of intramandibular sutures or the greater amount of cancellous bone present in the postdentary region of the mandible and requires further study. This study highlights the predictive potential of even simple FE models for studies in extant and extinct vertebrates, but also emphasizes the importance of geometry and sutures. It raises the question of whether different parameters are of lesser or greater importance to FE validation for different taxonomic groups.

Kinematic and kinetic parameters of running gait were investigated through growth in the ostrich, from two weeks up to 10 months of age, in order to investigate the effects of increasing body size. Ontogenetic scaling relationships were compared with published scaling relationships found to exist with increasing body size between species to determine whether dynamic similarity is maintained during growth. During the study, ostrich mass (M(b)) ranged from 0.7 kg to 108.8 kg. Morphological measurements showed that lengths scaled with positive allometry during growth (hip height proportional to M(b)(0.40); foot segment length proportional to M(b)(0.40); tarsometatarsus length proportional to M(b)(0.41); tibiotarsus length proportional to M(b)(0.38); femur length proportional to M(b)(0.37)), significantly exceeding the close to geometric scaling observed between mammalian and avian species of increasing body size. Scaling of kinematic variables largely agreed with predicted scaling for increasing size and demonstrated relationships close to dynamic similarity and, as such, ontogenetic scaling of locomotor parameters was similar to that observed with increasing body mass between species. However, the ways in which these scaling trends were achieved were very different, with ontogenetic scaling of locomotor mechanics largely resulting from simple scaling of the limb segments rather than postural changes, likely to be due to developmental constraints. Small deviations from dynamic similarity of kinematic parameters and a reduction in the predicted scaling of limb stiffness (proportional to M(b)(0.59)) were found to be accounted for by the positive allometric scaling of the limb during growth.

In this study, retinal whole-mount specimens were prepared and stained with 0.1% cresyl violet for the ganglion cell study in the ostrich (Struthio camelus). The total number, distribution, and size of these cells were determined in different retinal regions. The mean total number of ganglion cells (three retinas) was 1,435,052 with an average density of 652 cells/mm(2). The temporo-nasal area of the retina with high cell density were identified with the peak of 7525 cells/mm(2) in the central area. The size of most ganglion cells ranged from 113-403 microm(2), with smaller cells predominating along the temporo-nasal streak above the optic disc and larger cells comprising more of the peripheral regions. The average thickness of the retina was 196 microm. The central area was the thickest area (268.6 microm), whereas the peripheral area was the thinnest area. Thus, the specialization of ganglion cell densities, their sizes and the thickness of the retina support the notion that the conduction of visual information towards the brain from all regions of the retina is not uniform, and suggests that the temporo-nasal streak is the fine quality area for vision in ostriches.

We examined the external anatomy of the endocast of the Greater Rhea (Rhea americana, Palaeognathae), during 3 main stages of its postnatal life, and compared it with information available on other palaeognathous birds. Series of scans with spiral computed tomographies were obtained from 3 skulls of different ages (chick, juvenile and adult) of R. americana; digital 3-dimensional reconstruction was performed and brain volumes were calculated from the models obtained. Qualitative assessment of the brain anatomy of R. americana indicates a conical and ventrally located bulbus olfactorius, laterally expanded hemispherium telencephali, well-developed eminentia sagittalis, and conspicuous cerebellum and tectum mesencephali. Anatomy of the chick brain was markedly different: less lateral expansion of the hemispherium telencephali, and lesser development of the eminentia sagittalis and auricula cerebelli. Little change between chicks and adults was observed in some brain regions such as the tectum mesencephali, while the eminentia sagittalis showed great increase in size. The large size of the eminentia sagittalis coupled with its increasing development during ontogeny could reflect its importance for visual processing functions and the way these improve during growth. Finally, the brain of R. americana is similar to that of Struthio and Dromaius, but differs from that of the Tinamidae and of Apteryx, allowing recognition of 3 distinct brain morphologies among the Palaeognathae.

In birds, the ability to void urine separate from faeces is unique to ostriches. To further explore this characteristic, the anatomy of the terminal rectum and cloaca of the Ostrich Struthio camelus was studied in four ostriches by gross anatomical dissection and light microscopy. The terminal rectum had an unusual tunica muscularis externa (TME) and was clearly demarcated from the caudal part of the rectum proper by a semilunar fold, an abrupt thickening of the gut wall and an increase in the calibre of the gut. The cloaca had a distinct rectocoprodeal fold at the terminal rectum–cloaca junction with a well-formed sphincter muscle. The cloaca had a proximal coprodeum, a middle urodeum and a caudal proctodeum. The mucosa of the cloaca was folded and lined by simple columnar epithelium except in the urodeum and the floor and ventral walls of the proctodeum. The coprodeal wall had a thick circular muscle layer; however, the other parts of the cloaca mainly had longitudinally/obliquely directed fibres in the TME. This muscle arrangement could contribute to the dynamics of the terminal rectum that allow for separate defecation and micturition. We also propose a schema for this phenomenon that for birds is unique to ostriches. OSTRICH 2009, 80(3): 185–191

In order to characterize lesions associated with Codiostomum struthionis in ostriches, 10 caeca were examined on both macro- and microscopic levels. Parasites were found in the distal third of the caecum and characterized as C. struthionis. Thickened mucosa was identified macroscopically where parasites were observed in high concentrations. Nodular areas were also observed in the distal third of the infected caeca, as well as hemorrhagic areas abutting small ulcers surrounded by edema. These findings were not observed in healthy controls. The concentration of C. struthionis found in infected animals was directly correlated with the severity of lesions observed in each caecum. These results allowed us to infer that C. struthionis is responsible for lesions in ostrich caeca.

SUMMARY Living archosaurs (crocodiles and birds) represent an intriguing evo-devo model system. Although close in phylogenetic relationship, the two lineages show considerable divergence in trends of phenotypic evolution. The head anatomy of recent crocodilians has changed little in comparison with that of their crocodylomorph ancestors. The head phenotype of the avians (birds), as well as some non-avian theropods, shows numerous evolutionary innovations that differ considerably from the crocodylomorph pattern. Most of the novel head structures, such as features of the craniofacial skeleton, cranial nerves, head muscles, and integument are derived from the same cellular source common to all archosaurs, the cephalic neural crest (CNC). Therefore, other factors must be involved in the developmental disparity of homologous structures in the aforementioned lineages. The present study analyzes the earliest developmental events that are associated with the appearance of the neural crest cells in the two archosaur models: Crocodylus niloticus and Struthio camelus. I found that both models share unique developmental features, the presence of an unpaired, rostrally migrating population of CNC cells, showing that the two are closely related to each other. On the other hand, the crocodile and the ostrich differ substantially in (1) timing, (2) duration, and (3) expression patterns of the CNC. Compared with the crocodile, the CNC cells in the ostrich (1) migrate much later into the embryonic head, (2) but relocate to their terminal positions faster, and (3) take specifically directed migratory routes in the mandibular/oral region and head/trunk-interface regions. I suggest that accelerated relocation of CNC cells combined with delayed head organogenesis may represent important innovative conditions in the developmental evolution of a new archosaur head phenotype.