Keratinophilic fungi from the feathers of Emu (Dromaius novaehollandiae) in Maharastra India.

A total of 70 feathers samples of Emu (Dromaius novaehollandiae) were collected from 7 Emu farms situated at two districts (Raigad and Thane) of Maharashtra (India) and screened for resident keratinophilic fungi. Among them, 44 isolates were recovered and identified by evaluating characteristic macro- and micro-morphological features. Further gene products corresponding to the ITS1-5.8S-ITS2 rDNA region from all isolates were amplified and sequenced. Homology search was performed using BLAST program against non-redundant nucleotide database, and significantly matched DNA sequences deposited to the NCBI Gene Bank for reference purposes. Eight identified fungal species belongs to 7 different genera named as Aphanoascus terreus Ac_MW577456 (21.43%), Microsporum gypseum Ac_MW580920 (14.29%), Ctenomyces serratus Ac_MW577459 (10.0%), Uncinocarpus orissi Ac_MW577461 (5.17%), Aphanoascus verrucosus Ac_MW577458 (4.29%), Gymnascella dankaliensis Ac_MW577460 (2.86%), Gymnoascoideus petalosporus Ac_MW577462 (2.86%) and Arthroderma tuberculatum Ac_MW577457 (1.43%).

Morphometry of the cervical spine of emu using the hydrostatic method / Morfometría de la columna cervical de emu usando el método hidrostático

The study aimed at estimating the values of basic metric traits of emu cervical vertebrae. The study was conducted on the vertebrae of 6 male and 10 female emus being fourteen years old. Osteometric measurements were performed with electronic callipers, while the hydrostatic method was used to assess the density and volume of each vertebra. The sex of birds was considered a source of variation. The cervical spine had 17 vertebrae. Dimorphism was found in basic metric traits between analogous emu vertebrae of both sexes. The female vertebrae were characterised by significantly (P≤0.05 and P≤0.01) greater length, breadth and height than the male ones. No dimorphic differences were found in the volume of bone mass for vertebrae 1 to 8, whereas female vertebrae 9 to 17 had greater (P≤0.05) volume compared to the male ones. Correlation coefficients for body weight, vertebra volume and spinal canal capacity were weak. The sum of the length of vertebral bodies determining the length of neck showed significantly (P≤0.01) longer necks in female emus. No narrowing and extensions of the vertebral canal for the spinal cord running in it was found throughout the whole cervical spine.

Este estudio tuvo como objetivo la estimación de los valores de los rasgos métricos básicos de las vértebras cervicales del Emu. El estudio se realizó en vértebras de 6 machos y 10 hembras Emu de catorce años. Las mediciones osteométricas se realizaron con pinzas electrónicas, mientras que el método hidrostático se usó para evaluar la densidad y el volumen de cada vértebra. El sexo de las aves se consideró como una variación. La columna cervical contaba con 17 vértebras. Se encontró dismorfismo en rasgos métricos básicos entre vértebras análogas de ambos sexos. Las vértebras de las hembras se caracterizaron por una longitud, ancho y altura significativamente mayor (P≤0,05 y P≤0,01) a las de los machos. No se encontraron diferencias dismórficas en el volumen de masa ósea para las vértebras 1 a 8, mientras que las vértebras de las hembras 9 a 17 tuvieron un volumen mayor (P≤0,05) en comparación con los machos. Los coeficientes de correlación para el peso corporal, el volumen de la vértebra y la capacidad del canal espinal fueron débiles. La suma de la longitud de los cuerpos vertebrales que determina la longitud del cuello mostró significativamente (P≤0.01) cuellos más largos en las hembras. No se observaron estrechamientos y extensiones del canal vertebral para la médula espinal que se encuentra en toda la columna cervical.

Genetic diversity and drivers of dwarfism in extinct island emu populations.

Australia's iconic emu (Dromaius novaehollandiae novaehollandiae) is the only living representative of its genus, but fossil evidence and reports from early European explorers suggest that three island forms (at least two of which were dwarfs) became extinct during the nineteenth century. While one of these-the King Island emu-has been found to be conspecific with Australian mainland emus, little is known about how the other two forms-Kangaroo Island and Tasmanian emus-relate to the others, or even the size of Tasmanian emus. We present a comprehensive genetic and morphological analysis of Dromaius diversity, including data from one of the few definitively genuine Tasmanian emu specimens known. Our genetic analyses suggest that all the island populations represent sub-populations of mainland Dnovaehollandiae Further, the size of island emus and those on the mainland appears to scale linearly with island size but not time since isolation, suggesting that island size-and presumably concomitant limitations on resource availability-may be a more important driver of dwarfism in island emus, though its precise contribution to emu dwarfism remains to be confirmed.

Bony Pits in the Ostrich (Struthio camelus) and Emu (Dromaius novaehollandiae) Bill Tip.

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.

Fusion Patterns in the Skulls of Modern Archosaurs Reveal That Sutures Are Ambiguous Maturity Indicators for the Dinosauria.

The sutures of the skulls of vertebrates are generally open early in life and slowly close as maturity is attained. The assumption that all vertebrates follow this pattern of progressive sutural closure has been used to assess maturity in the fossil remains of non-avian dinosaurs. Here, we test this assumption in two members of the Extant Phylogenetic Bracket of the Dinosauria, the emu, Dromaius novaehollandiae and the American alligator, Alligator mississippiensis, by investigating the sequence and timing of sutural fusion in their skulls. As expected, almost all the sutures in the emu skull progressively close (i.e., they get narrower) and then obliterate during ontogeny. However, in the American alligator, only two sutures out of 36 obliterate completely and they do so during embryonic development. Surprisingly, as maturity progresses, many sutures of alligators become wider in large individuals compared to younger, smaller individuals. Histological and histomorphometric analyses on two sutures and one synchondrosis in an ontogenetic series of American alligator confirmed our morphological observations. This pattern of sutural widening might reflect feeding biomechanics and dietary changes through ontogeny. Our findings show that progressive sutural closure is not always observed in extant archosaurs, and therefore suggest that cranial sutural fusion is an ambiguous proxy for assessing maturity in non-avian dinosaurs.

Morphological features of Herbst corpuscles in the oropharynx of the ostrich (Struthio camelus) and emu (Dromaius novaehollandiae).

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.

Comparative distribution and arrangement of Herbst corpuscles in the oropharynx of the ostrich (Struthio camelus) and emu (Dromaius novaehollandiae).

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.

A re-evaluation of sperm ultrastructure in the emu, Dromaius novaehollandiae.

Existing reports on sperm structure in the emu do not adequately illustrate or describe all the salient ultrastructural features necessary for a meaningful comparison of normal and abnormal sperm in this species. As sperm morphology forms an important parameter in determining semen quality, and in view of the proposed role of artificial insemination in the farming of ratites, this article re-evaluates and complements the existing data on the topic, provides a fully illustrated description of emu sperm ultrastructure, and documents some unreported morphologic features. Conventional transmission and scanning electron microscopy and high resolution scanning electron microscopy were used to describe the ultrastructure of sperm harvested from the distal deferent duct of sexually mature birds slaughtered during the breeding season. In addition to broadly confirming the basic ultrastructural characteristics previously described for emu sperm, this study revealed a number of unreported morphologic features. These included distinct differences in surface properties between the acrosome and nucleus, the presence of a thread-like appendage near the base of the nucleus, variable positioning of the annulus relative to structures located at the midpiece-principal piece junction and regional differentiation of the principal piece. Although the emu displayed similar basic morphologic features to sperm of other ratites and the tinamou, marked structural peculiarities were obvious, notably the lack of an endonuclear canal and a perforatorium and the presence of significantly more mitochondria in the midpiece coupled with an absence of intermitochondrial cement. Although the broad morphologic features of emu sperm would appear to add credence to the general view that the ratites, together with the tinamous, form a monophyletic group at the base of the avian phylogenetic tree, it is also clear that emu sperm are distinctly different from those of the ostrich, rhea, and tinamou which together share morphologic affinities. This observation may lend some support to the alternate view that the Australasian ratites represent a separate clade that developed independently from flightless ancestors.

Iodine-enhanced micro-CT imaging: methodological refinements for the study of the soft-tissue anatomy of post-embryonic vertebrates.

The now widespread use of non-destructive X-ray computed tomography (CT) and micro-CT (µCT) has greatly augmented our ability to comprehensively detail and quantify the internal hard-tissue anatomy of vertebrates. However, the utility of X-ray imaging for gaining similar insights into vertebrate soft-tissue anatomy has yet to be fully realized due to the naturally low X-ray absorption of non-mineralized tissues. In this study, we show how a wide diversity of soft-tissue structures within the vertebrate head-including muscles, glands, fat deposits, perichondria, dural venous sinuses, white and gray matter of the brain, as well as cranial nerves and associated ganglia-can be rapidly visualized in their natural relationships with extraordinary levels of detail using iodine-enhanced (i-e) µCT imaging. To date, Lugol's iodine solution (I2 KI) has been used as a contrast agent for µCT imaging of small invertebrates, vertebrate embryos, and certain isolated parts of larger, post-embryonic vertebrates. These previous studies have all yielded promising results, but visualization of soft tissues in smaller invertebrate and embryonic vertebrate specimens has generally been more complete than that for larger, post-embryonic vertebrates. Our research builds on these previous studies by using high-energy µCT together with more highly concentrated I2 KI solutions and longer staining times to optimize the imaging and differentiation of soft tissues within the heads of post-embryonic archosaurs (Alligator mississippiensis and Dromaius novaehollandiae). We systematically quantify the intensities of tissue staining, demonstrate the range of anatomical structures that can be visualized, and generate a partial three-dimensional reconstruction of alligator cephalic soft-tissue anatomy.

Digit loss in archosaur evolution and the interplay between selection and constraints.

Evolution involves interplay between natural selection and developmental constraints. This is seen, for example, when digits are lost from the limbs during evolution. Extant archosaurs (crocodiles and birds) show several instances of digit loss under different selective regimes, and show limbs with one, two, three, four or the ancestral number of five digits. The 'lost' digits sometimes persist for millions of years as developmental vestiges. Here we examine digit loss in the Nile crocodile and five birds, using markers of three successive stages of digit development. In two independent lineages under different selection, wing digit I and all its markers disappear. In contrast, hindlimb digit V persists in all species sampled, both as cartilage, and as Sox9- expressing precartilage domains, 250 million years after the adult digit disappeared. There is therefore a mismatch between evolution of the embryonic and adult phenotypes. All limbs, regardless of digit number, showed similar expression of sonic hedgehog (Shh). Even in the one-fingered emu wing, expression of posterior genes Hoxd11 and Hoxd12 was conserved, whereas expression of anterior genes Gli3 and Alx4 was not. We suggest that the persistence of digit V in the embryo may reflect constraints, particularly the conserved posterior gene networks associated with the zone of polarizing activity (ZPA). The more rapid and complete disappearance of digit I may reflect its ZPA-independent specification, and hence, weaker developmental constraints. Interacting with these constraints are selection pressures for limb functions such as flying and perching. This model may help to explain the diverse patterns of digit loss in tetrapods. Our study may also help to understand how selection on adults leads to changes in development.

Ancient DNA suggests dwarf and 'giant' emu are conspecific.

BACKGROUND: The King Island Emu (Dromaius ater) of Australia is one of several extinct emu taxa whose taxonomic relationship to the modern Emu (D. novaehollandiae) is unclear. King Island Emu were mainly distinguished by their much smaller size and a reported darker colour compared to modern Emu. METHODOLOGY AND RESULTS: We investigated the evolutionary relationships between the King Island and modern Emu by the recovery of both nuclear and mitochondrial DNA sequences from sub-fossil remains. The complete mitochondrial control (1,094 bp) and cytochrome c oxidase subunit I (COI) region (1,544 bp), as well as a region of the melanocortin 1 receptor gene (57 bp) were sequenced using a multiplex PCR approach. The results show that haplotypes for King Island Emu fall within the diversity of modern Emu. CONCLUSIONS: These data show the close relationship of these emu when compared to other congeneric bird species and indicate that the King Island and modern Emu share a recent common ancestor. King Island emu possibly underwent insular dwarfism as a result of phenotypic plasticity. The close relationship between the King Island and the modern Emu suggests it is most appropriate that the former should be considered a subspecies of the latter. Although both taxa show a close genetic relationship they differ drastically in size. This study also suggests that rates of morphological and neutral molecular evolution are decoupled.

Macroscopic anatomy of the reproductive tract of the reproductively quiescent female emu (Dromaius novaehollandiae).

Three reproductively quiescent female emus (Dromaius novaehollandiae) were embalmed with 10% formalin solution. The reproductive tract was dissected and described. The reproductive tract consists of an ovary and oviduct situated on the left side of the abdominal cavity. The left ovary is dark brown to black in colour with follicles covering the ventral surface. The ovary is located medial to the spleen and closely associated with the ventral surface of the cranial and middle lobes of the left kidney. The oviduct is a relatively straight tube that extends from the level of the cranial extent of the left ilium to the caudal border of the left pubic bone. The oviduct is grossly divided into the infundibulum, magnum, isthmus, uterus and vagina using variations in the mucosal fold pattern.

Reproductive tract vasculature of the female emu (dromaius novaehollandiae).

The arterial supply of the ovary and oviduct is provided by the ovarian artery, cranial oviductal artery, accessory cranial oviductal artery, middle oviductal artery, caudal oviductal artery and the medial and lateral vaginal arteries. These arteries supply various regions of the oviduct and are branches of either the left cranial renal artery, left external iliac artery, left middle renal artery, left lateral caudal artery or the left pudendal artery. The veins that drain the reproductive tract are satellite vessels to each artery that supplied the tract.

Surface morphology of the emu (Dromaius novaehollandiae) tongue.

Despite numerous morphological studies on the avian tongue, very little meaningful information is currently available on the surface features of this organ using scanning electron microscopy (SEM). The only SEM description of a ratite tongue is that of the ostrich, although the descriptions are brief and superficial. This SEM study of the emu tongue confirms and compliments the comprehensive macroscopic and histological data available for this commercially important species. The tongues of five emus were fixed, cut into blocks representing the dorsum, ventrum and root and routinely processed for SEM. Three morphologically distinguishable surface types (desquamating, non-desquamating and lymphoepithelium) related to peculiarities in surface cell shape and status (desquamating or non-desquamating), cell surface modifications and distribution of gland openings, and which showed a regional distribution, could be identified. Three basic types of cell surface modifications (microplicae, microvilli and cilia) were observed, with microvilli and cilia being described for the first time in an avian tongue by SEM. The desquamating surface cells fulfil a mechanical protective function, whereas the microplicae, microvilli and cilia appear to be adaptations for the trapping and spreading of mucus which also fulfils a protective function.

Gross morphology of the intra-oral rhamphotheca, oropharynx and proximal oesophagus of the emu (Dromaius novaehollandiae).

Information on the gross morphology of the upper digestive tract of ratites is sparse. This is an important region considering that it is the first area for food selection and intake which is vital to the nutrition and growth of the animal and therefore its commercial viability. Twenty-three heads from sub-adult (12-14 months) emus were used to provide a definitive description of the oropharynx and proximal oesophagus. Besides supplying baseline morphological data of veterinary importance, this study also underlines the functional importance of this region. The mandibular and maxillary nails, and serrations on the rostral mandibular tomia, provide the emu with a formidable combination of gripping, tearing and pecking power. The folded oropharyngeal floor allows distention of the dorso-ventrally flattened cavity during eating and drinking. The laryngeal mound performs both respiratory and digestive functions, whereas the distensible proximal oesophagus supports the particular feeding method employed by ratites.

Morphology of the tongue of the emu (Dromaius novaehollandiae). I. Gross anatomical features and topography.

Despite numerous papers addressing the topic, the gross morphology of the ratite tongue and more specifically that of the emu, has been superficially or poorly described. This paper presents the first definitive macroscopic description of the emu tongue and reviews, consolidates and compares the scattered information on the gross morphology of the ratite tongue available in the literature. Twenty-three heads obtained from birds at slaughter were used for this study. Specimens were fixed in 10 % neutral buffered formalin, rinsed and the gross anatomy described. The emu tongue is divided into a body and a root. The body is triangular, dorsoventrally flattened, pigmented and displays caudally directed lingual papillae on both the lateral and caudal margins. The root, a more conspicuous structure in comparison to other ratites, is triangular, with a raised bulbous component folding over the rostral part of the laryngeal fissure. Following the general trend in ratites, the emu tongue is greatly reduced in comparison to the bill length and is specifically adapted for swallowing during the cranioinertial method of feeding employed by palaeognaths. This study revealed that it is not only the shape of the tongue that differs between ratites, as previously reported, but also its colour, appearance of its margins and root, and its length in comparison to the bill, and the shape of the paraglossum.

Morphology of the tongue of the emu (Dromaius novaehollandiae). II. Histological features.

Although a number of brief, fragmented descriptions have been provided on the gross morphology of the ratite tongue, very few studies have documented the histological structure of this organ. This paper presents the first definitive histological description of the emu tongue and reviews, consolidates and compares the scattered information on the histology of the ratite tongue available in the literature. Five tongues were removed from heads obtained from birds at slaughter and fixed in 10% neutral buffered formalin. Appropriate longitudinal and transverse segments were removed, routinely processed for light microscopy, and sections examined after staining with H & E and PAS. The entire tongue (body and root) is invested by a non-keratinized stratified squamous epithelium. The supporting connective tissue of the tongue dorsum displays only large, simple branched tubular mucus-secreting glands, whereas the caudal tongue body ventrum and tongue root, in addition to these glands, also exhibits small, simple tubular mucus-secreting glands. Herbst corpuscles are associated with the large, simple branched glands. Lymphoid tissue is restricted to the tongue ventrum and is particularly obvious at the junction of the ventral tongue body and frenulum where a large aggregation of diffuse lymphoid tissue, with nodular tissue proximally, was consistently observed. A structure resembling a taste bud was located in the epithelium on the caudal extremity of the tongue root of one bird. This is the first reported observation of taste buds in ratites. Forming the core of the tongue body is the cartilaginous paraglossum lying dorsal to the partially ossified rostral projection of the basihyale. The histological features of the emu tongue are generally similar to those described for the greater rhea and ostrich, except that taste buds were not identified in these species. The results would suggest that the emu tongue functions as a sensory organ, both for taste and touch (by virtue of taste receptors and Herbst corpuscles, respectively), as well as fulfilling an immunological function.

Morphological and immunohistochemical study of testicular capsule and peritubular tissue of emu (Dromaius novaehollandiae) and ostrich (Struthio camelus).

The testicular capsule and peritubular boundary tissue of the emu and ostrich, as typical representatives of ratite birds, were studied in sexually mature and active birds. The testicular capsule was much thicker (578.1+/-73.4 microm for the free surface of the ostrich testis, and 176.2+/-57.5 microm for the emu) than those of members of the Galloanserae. The cellular composition of both testicular capsule and peritubular tissue was similar generally to that of members of the previously studied Galloanserae and of mammals. The tunica albuginea of the testicular capsule mainly comprised smooth-muscle-like or myoid cells mostly running in one direction and occurring in one main mass. Unlike the Galloanserae, the tunica albuginea contained more collagen fibres than smooth muscle cells, especially in the ostrich. Peritubular tissue was similarly composed of smooth-muscle-like cells distributed in several layers. Actin microfilaments and desmin and vimentin intermediate filaments were variably immunoexpressed in these two tissue types in both birds, with a clear dichotomy in the peritubular tissue. Thus, taken together with studies of some members of the Galloanserae, avian testes clearly contain a morphological mechanism that is represented partly by the smooth muscle cells of the testicular capsule and peritubular tissue for transporting the testicular fluid, which is usually copious in birds, and its cellular content from the testis into the excurrent duct system; this mechanism is similar to that found in mammals.

Hip joint contact force in the emu (Dromaius novaehollandiae) during normal level walking.

The emu is a large, (bipedal) flightless bird that potentially can be used to study various orthopaedic disorders in which load protection of the experimental limb is a limitation of quadrupedal models. An anatomy-based analysis of normal emu walking gait was undertaken to determine hip contact forces for comparison with human data. Kinematic and kinetic data captured for two laboratory-habituated emus were used to drive the model. Muscle attachment data were obtained by dissection, and bony geometries were obtained by CT scan. Inverse dynamics calculations at all major lower-limb joints were used in conjunction with optimization of muscle forces to determine hip contact forces. Like human walking gait, emu ground reaction forces showed a bimodal distribution over the course of the stance phase. Two-bird averaged maximum hip contact force was approximately 5.5 times body weight, directed nominally axially along the femur. This value is only modestly larger than optimization-based hip contact forces reported in literature for humans. The interspecies similarity in hip contact forces makes the emu a biomechanically attractive animal in which to model loading-dependent human orthopaedic hip disorders.

An immunohistochemical study of the distribution of intermediate filaments in the ovary of the emu (Dromaius novaehollandiae).

The immunohistochemical localization of the intermediate filaments desmin, vimentin and smooth muscle actin (SMA) in the ovary of the emu was described in the present study. The cortical region of the ovary contained developing and atretic primordial, pre-vitellogenic and vitellogenic follicles. Vimentin immunostaining was demonstrated in the granulosa cell layer of primordial, pre-vitellogenic and vitellogenic developing and atretic follicles. An interesting finding of the present study was the localization of SMA in fibroblasts located in the theca externa of late vitellogenic follicles. The presence of SMA in these fibroblasts suggests that they possess characteristics of smooth muscle cells.