Morphometric Variations in the Skin Layers of Frogs: An Exploration Into Their Relation With Ecological Parameters in Leptodactylus (Anura,Leptodactylidae), With an Emphasis on the Eberth‐Kastschenko Layer

Leptodactylus is a genus of frogs known to live in diverse habitats and to show both aquatic and terrestrial breeding habits. We studied 21 species of Leptodactylus to explore whether skin structure specialization relates to habitats and habit variation. Morphometric analyses of the skin thickness revealed that phylogeny has a strong influence on variations in the thickness of the epidermis, stratum spongiosum, Eberth‐Kastschenko layer, and stratum compactum, while habitat and habits display no significant correlation. The optimization of the phylogenetic hypothesis suggested that a pattern of intermediate values for skin layer thickness are plesiomorphic for this group. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1895–1909, 2017. © 2017 Wiley Periodicals, Inc.     

The Role of Ellis‐Van Creveld 2(EVC2) in Mice During Cranial Bone Development

EvC syndrome is a type of autosomal‐recessive chondrodysplasia. Previous case studies in patients suggest abnormal craniofacial development, in addition to dwarfism and tooth abnormalities. To investigate how craniofacial development is affected in EvC patients, surface models were generated from micro‐CT scans of control mice, Evc2 global mutant mice and Evc2 neural crest‐specific mutant mice. The anatomic landmarks were placed on the surface model to assess the morphological abnormalities in the Evc2 mutants. Through analyzing the linear and angular measurements between landmarks, we identified a smaller overall skull, shorter nasal bone, shorter frontal bone, and shorter cranial base in the Evc2 global mutants. By comparing neural crest‐specific Evc2 mutants with control mice, we demonstrated that the abnormalities within the mid‐facial regions are not accounted for by the Evc2 mutation within these regions. Additionally, we also identified disproportionate length to width ratios in the Evc2 mutants at all levels from anterior to posterior of the skull. Overall, this study demonstrates a more comprehensive analysis on the craniofacial morphological abnormalities in EvC syndrome and provides the developmental insight to appreciate the impact of Evc2 mutation within the neural crest cells on multiple aspects of skull deformities. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:46–55, 2018. © 2017 Wiley Periodicals, Inc.     

Escapees from Rhombomeric Lineage Restriction: Extensive Migration Rostral to the r4/r5 Border of Hox‐a3 Expression

The rhombomeric compartments of the hindbrain are characterized by lineage restriction; cells born in one compartment generally remain there and do not migrate to neighboring rhombomeres. Two well‐known exceptions are the substantial migrations of the pontine nuclei and the mammalian facial nucleus. In this study we used Hoxa3‐Cre lineage to permanently mark cells that originate in rhombomeres caudal to r4. We found that cells born caudal to the r4/r5 border migrate forwards to a number of different locations in rhombomeres 1–4; the final locations include the interfascicular trigeminal nucleus, the principal trigeminal nucleus, the pontine nuclei, the reticulotegmental nucleus, the ventral nucleus of the lateral lemniscus, and the lateral and medial vestibular nuclei. We suggest that there are numerous exceptions to the principle of rhombomeric lineage restriction that have previously gone unnoticed. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1838–1846, 2017. © 2017 Wiley Periodicals, Inc.     

Natural development of dermal ectopic bone in the american alligator (Alligator mississippiensis) resembles heterotopic ossification disorders in humans

Heterotopic ossification (HO) occurs when soft tissues are inappropriately converted to bony tissue. Several human diseases result in HO with few reliable treatment options. Animal models that naturally produce dermal ectopic bone (i.e., osteoderms), such as crocodilians, have never been utilized as models for studying these disorders in humans. Here, a histological evaluation and staging criteria for osteoderm development is described for the first time in the American alligator (Alligator mississipiensis). Differential staining and immunohistochemistry of alligator scales depict a progressive change during development, where woven bone forms from the differentiated dermis. Bone formation proceeds via intramembranous ossification, which is initiated in part by endothelial cell precursors that undergo endothelial‐to‐mesenchymal transition and eventually acquire an osteoblast phenotype. As such, the development of osteoderms in the American alligator bears morphological and mechanistic similarities to HO in humans, presenting a potential model for future study of soft tissue mineralization pathologies and providing insight into the morphological and molecular development of osteoderms in other vertebrate lineages. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:56–76, 2018. © 2017 Wiley Periodicals, Inc.     

First Natural Endocranial Cast of a Fossil Snake (Cretaceous of Patagonia,Argentina)

In this study, we describe a natural endocranial cast included in a partially preserved medium‐sized skull of the Upper Cretaceous South American snake Dinilysia patagonica. The endocast is composed of sedimentary filling of the cranial cavity in which the posterior brain, the vessels, the cranial nerves, and the inner ear surrounded by delicate semicircular canals, are represented. It is simple in form, with little differentiation between the three main areas (Forebrain, Midbrain, and Hindbrain), and without flexures. The nervous system is well preserved. The posterior brain surface is smooth, except for two small prominences that make up the cerebellum. A large inner ear is preserved on the right side; it consists of a voluminous central mass, the vestibule, which occupies most of the space defined by the three semicircular canals. In particular, the lateral semicircular canal is very close to the vestibule. This characteristic, in combination with the medium to large body size of Dinilysia, its large skull and dorsally exposed orbits, and vertebrae bearing a rather high neural spine on a depressed neural arch, suggests that this snake would have had a semifossorial lifestyle. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:9–20, 2018. © 2017 Wiley Periodicals, Inc.     

Vertebral Development and Ossification in the Siberian Sturgeon (Acipenser Baerii), with New Insights on Bone Histology and Ultrastructure of Vertebral Elements and Scutes

In order to improve our knowledge on the vertebral development, structure and mineralization in Acipenseriformes, we undertook a study in a growth series of reared Siberian sturgeons (Acipenser baerii) using in toto clear and stain specimens, histological and ultrastructural observations, X‐ray micro‐tomography, and solid state NMR analyses. Scutes were also studied to compare the tissue structure and mineralization of endoskeletal and dermal skeletal elements. This study completes and clarifies previous investigations on vertebral development and architecture in sturgeons, and brings original data on the structure of (i) the perichondral bone that is progressively deposited around the vertebral elements during ontogeny, (ii) the typical cartilage composing these elements, and (iii) the scutes. In addition we provide data on the mineralization process, on the nature of the bone mineral phase, and on the growth dynamics of the vertebral elements. Anat Rec, 300:437–449, 2017. © 2016 Wiley Periodicals, Inc.     

Skull Anatomy and Ontogeny of Legless Lizard Pseudopus apodus (Pallas, 1775): Heterochronic Influences on Form

Pseudopus apodus (Pallas, 1775) is the largest extant legless species of the subfamily Anguinae (Anguimorpha, Anguidae) living mostly in the sub‐arid territories ranging from the Balkan area in Europe to Kazakhstan in Asia. The species of other two genera live in North America, South‐East Asia and North Africa (Ophisaurus) and Europe and South‐West Asia (Anguis). The interrelationships of Anguinae are unresolved; this is in part the consequence of the insufficient knowledge of the cranial, postcranial and integumentary anatomy of the individual anguine species. The aim of this article is to fulfill this gap in our knowledge of the anguine anatomy. Now, in the first part of the project, the individual bones of the exocranium and visceral endocranium of the anguine legless lizard P. apodus are described in detail. In the present study, P. apodus is revealed to have autoapomorphic features of the skull which clearly distinguish it from Anguis and Ophisaurus. In addition, the study of posthatchling ontogeny of exocranium of P. apodus revealed some features, such as a nasal process of premaxilla being slightly widened in about its mid‐length, that are also typical for adults of the Ophisaurus and Anguis species as well as extinct species of Pseudopus. This strongly indicates that peramorphic heterochronic process played role in the evolution of the P. apodus skull. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:460–502, 2017. © 2016 Wiley Periodicals, Inc.     

The Sacral Autonomic Outflow Is Spinal,but Not “Sympathetic”

A recent article published in a high‐profile journal proposed to reclassify the sacral autonomic outflow as being part of the sympathetic system. In this commentary, arguments against this erroneous proposal are provided. Anat Rec, 300:1369–1370, 2017. © 2017 Wiley Periodicals, Inc.     

Spermatogenic Cycle and Steroidogenic Control of Spermatogenesis in Mytilus galloprovincialis Collected in the Bay of Naples

The aim of the present article was to study the spermatogenic cycle of Mytilus galloprovincialis collected in the Bay of Naples during a whole year and to acquire new insights into the mechanism of control. Knowledge of the Mytilus cycle in this geographic area is of particular interest as, to the best of our knowledge, the male gonad cycle has been hitherto unexplored. Testis organization was evaluated together with the localization of the enzymes 3β‐HSD, 17β‐HSD, and P450‐aromatase, which are strictly connected to the synthesis of two key hormones involved in the testis activity: testosterone and 17β‐estradiol. It was demonstrated that: (1) the spermatogenic cycle starts in late Summer‐early Fall and continues until early Winter, when the first spawning occurs; after rapid gonad restoration, several spawning events take place until June, when the testis becomes non‐active again; (2) in the testis, true Leydig and Sertoli cells are present; (3) during the reproductive period, Sertoli, Leydig, germ, and adipogranular cells (ADGs) are positive to 3β‐HSD and 17β‐HSD, while only germ cells are positive to P450 aromatase; by contrast, during the resting period, only ADGs are positive to 3β‐HSD and 17β‐HSD, and P450‐aromatase is no longer recognizable. The presence of a hermaphrodite sample is also described. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1881–1894, 2017. © 2017 Wiley Periodicals, Inc.     

A Novel Method for Observation of the Mandibular Foramen: Application to a Better Understanding of Dental Anatomy

Cone‐beam computed tomography gives us much useful morphological information about the mandibular bone. Many studies of the mandible include findings from this technique. However, there have been no endoscopic studies of the mandible. Sixteen sides of eight dry mandibles resected from cadavers (age range 38–83 years) were examined by endoscopy. The head of the endoscope was 2.0 mm in diameter. We examined the mandibular foramen, lingula, mylohyoid groove, and mandibular canal. The mylohyoid grooves showed variations such as double grooves and canals. The mandibular lingula was located superior or medial to the the mandibular foramen. In a single case, the medial wall inside the mandibular canal showed a porous surface. The retromolar canal was observed in three sides. None of the images in the present study have been seen in other studies. Observation of the retromolar canal from the mandibular canal in particular can help dental students as well as oral and maxillofacial surgeons to understand its morphology. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1875–1880, 2017. © 2017 Wiley Periodicals, Inc.     

The Cytoarchitecture of the Telencephalon of Betta Splendens Regan 1910 (Perciformes: Anabantoidei) with a Stereological Approach to the Supracommissural and Postcommissural Nuclei

Teleostean fish brains are useful models to study cellular and functional specializations along the phylogenesis. The Betta splendens Regan 1910 (Siamese fighting fish; Perciformes:Anabantoidei) is known for its aggressive display, courtship behavior, nest building, and offspring care. Here, we present novel and detailed data about the cytoarchitecture of the olfactory bulb and the telencephalic hemispheres of this fish. The hematoxylin‐eosin and Nissl techniques served to identify brain nuclei (n = 19 males and n = 21 females) and for the stereological evaluation of the numerical density of cells and the proportion of neurons and glial cells in the ventral telencephalon supracommissural (Vs) and postcommissural (Vp) nuclei of adult males and females. These nuclei are putative homologs of the sexually dimorphic medial amygdala in mammals. The olfactory bulb of Betta splendens consists of 5 concentrically arranged layers plus ganglion cells of the terminal nerves. The dorsal telencephalon consists of 16 different cell groups. The ventral telencephalon has 8 nuclei, plus the lateral septal organ and the nuclei of the preoptic area forming an anatomical continuum. The rostrocaudal extent of the Vs and Vp is not different between sexes. In both nuclei, the proportion of neurons to glial cells is approximately 2:1 and the density of neurons and glial cells is not different between sexes. These morphological findings can subserve future research on the brain function of the Betta splendens and the search for neural sex differences in other central areas of this same species, in other teleost species, or yet in other related vertebrate group. Anat Rec, 00:000–000, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:88–110, 2018. © 2017 Wiley Periodicals, Inc.     

Acrolein Scavenger Hydralazine Prevents Streptozotocin‐Induced Painful Diabetic Neuropathy and Spinal Neuroinflammation in Rats

Diabetes‐induced neuropathic pain (DNP) substantially influences people's life qualities. Hyperglycemia‐induced excess free radicals have been considered as the most critical mechanisms underlying DNP. As an unsaturated aldehyde and a reactive product of lipid peroxidation, acrolein plays critical roles in diabetic nephropathy and inflammatory pain. We sought to determine whether acrolein is involved in DNP in this study. Diabetes was induced by a single intraperitoneal (i.p.) injection of 60 mg/kg streptozotocin (STZ). An acrolein scavenger hydralazine (5 mg/kg) was administered through a daily injection for 4 weeks, starting immediately within 30 min after STZ injection. Western blot showed that hydralazine could effectively inhibit STZ‐induced upregulation of acrolein in the spinal dorsal horn on day 7–28 after STZ injection. Behavioral tests showed that STZ injection induced significant mechanical allodynia and thermal hyperalgesia, which could be alleviated by hydralazine. Immunofluorescent histochemistry and Western blot showed that STZ induced significant microglial activation. ELISA data indicated upregulation of inflammatory cytokines IL‐1β and TNF‐α expression in the spinal dorsal horn. Furthermore, hydralazine effectively attenuated microglial activation and expression of inflammatory mediators. Our data indicate that acrolein might be involved in the development of neuroinflammation and behavioral consequences of DNP. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1858–1864, 2017. © 2017 Wiley Periodicals, Inc.     

The Relationship Between Linear Osteological and Radiographic Measurements of the Human Calcaneus and Talus

Plain radiographs of the foot are a common form of examination in individuals when medical evaluation is indicated. Their availability makes them useful for studying human variation where large sample sizes are crucial. Calcaneal and talar morphology are critical in the understanding of human foot form and function, but few studies have examined the accuracy of linear measurements of these bones taken from radiographs. If linear measurements are to be used in quantitative analysis, their accuracy must first be demonstrated. For this study, 54 human feet from amputated limbs were imaged in standard radiographic views and skeletonized. Selected linear measurements were made on each skeletonized talus and calcaneus. Corresponding landmarks were identified on the radiographic images and the distances between these points determined. Using the measurements taken from the physical bone, the accuracy of the radiographic measurements was evaluated employing paired Student's t‐tests and correlation analysis. Most measurements were not significantly different (P ≥ 0.05). Overall, the sagittal plane measurements were correlated (r² > 0.61–0.88, all P < 0.001) with the radiographic measurements; transverse plane measurements less so (r² = 0.20–0.63, P < 0.001). These results demonstrate that measurements from radiographic images provide useful information concerning both the calcaneus and talus, indicating that radiographs of living individuals can be evaluated quantitatively and compared to osteology collections of modern humans. This information can be applied to the understanding of functional anatomy of the modern human foot, interpreting the hominin fossil pedal record, and establishing identification in forensic analysis. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:21–33, 2018. © 2017 Wiley Periodicals, Inc.     

Partite hallux sesamoid bones: Relationship with sesamoid bones at other metatarsophalangeal joints

Partite hallux sesamoids are clinically meaningful but their association with other sesamoids is not clear. The objective was to relate the prevalence of the partite hallux sesamoid bones to sesamoid bones at other metatarsophalangeal (MTP) joints. We conducted a retrospective review of plain radiographs of 7946 adult feet between November 2005 and September 2012 to identify partite hallux sesamoids and sesamoids at other MTP joints. Coexistence patterns of the partition and extra sesamoids were studied. Presence or absence of sesamoids at other MTP joints as well as sex and laterality were compared between the feet with and without partite hallux sesamoids using Pearson Chi‐square test. Association between age and partition was evaluated using Spearman's correlation coefficient. Overall partite prevalence rate is 6.82%, and coexistence with extra MTP sesamoids was 0.42%. One pattern was partition in hallux sesamoid only, and 4 patterns were coexistence with extra sesamoids. The prevalence rates of partite hallux sesamoids were 7.17% (508/7081) and 3.93% (34/865) in feet without and with extra sesamoids, respectively. The relative risk of 1.889 (95% CI, 1.325–2.693) of partite hallux sesamoids was noted in feet without than with extra sesamoids (Χ² = 12.759, P < 0.001). A negative correlation between age and distribution of partition was identified (r = ?0.061, P < 0.001). Partition of hallux sesamoid bones is a developmental variation, it can coexist with sesamoids at other MTP joints following a certain pattern; and its prevalence rate is almost twice higher in feet without than with extra MTP sesamoids. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:34–38, 2018. © 2017 Wiley Periodicals, Inc.     

Sex Determination According to the Lengths of Hand Bones in Rhesus Macaques (Macaca Mulatta)

Measurement of hand bone length has been used for sex determination in humans and nonhuman primates (McFadden and Bracht: Early Hum Dev 85 (2009) 117–124; El‐Morsi and Al‐Hawary: J Forensic Leg Med 20 (2013) 6–13). The aim of this study was to determine the sex of rhesus macaques (Macaca mulatta) on the basis of the lengths of corresponding rows of metacarpals and phalanges in a macaque population by means of developing discriminant functions. Measurements on direct dry bones only included lengths for 19 bones of the left hand in 39 macaques (consisting of 13 adult males and 26 adult females). The results revealed that the mean values of males were significantly greater than those of females for all of the metacarpals and phalanges. The results were obtained in 84.4% of accuracy from distal phalanges, 93.8% from middle phalanges, and 96.9% from both metacarpals and proximal phalanges, respectively. There was a remarkable difference in the magnitude of sex dimorphism in lengths of each section of the hand bones between the population of macaques and humans. This difference may be attributable to the interaction between genetic factors and various environmental factors. As sex differences of hand bones are population‐specific (Lazenby: Am J phys Anthropol 118 (2002) 378–384; Lu, Huo, Shi, Peng, Dang, Jiao, Zhu, Zhong, and Chen: Acta Aantomica Sinica 39 (2008) 267–271; Eshak, Ahmed, and Gawad: J Forensic Leg Med 18 (2011) 246–252), the discriminant equations for all of the metacarpals and phalanges are applicable to the population of Macaca mulatta from the Taihang Mountain. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1741–1746, 2017. © 2017 Wiley Periodicals, Inc.     

On the Presence of the Patella in Frogs

The patella is one of the most studied sesamoids. Historically, the patella is described as a big sesamoid embedded in the tendon of the quadriceps femoris muscle. This sesamoid is studied from developmental, functional, clinical, and anatomical perspectives. The presence of a patella is reported in squamatans, birds, and mammals. Lissamphibians are identified as the major lineage that fail to develop a patella. However, this sesamoid is reported at least once in anurans, but without detailed anatomical discussions. Through anatomical and histological studies we examined the topography and tissue composition of two structures that we identify as the proximal and distal patellae in several anuran species. We explored the evolution of these sesamoids through ancestral state reconstruction, finding that they are ancestral for amphibians and possibly tetrapods as a whole. The presence of these patellae in anurans would roll back their origin to the last common ancestor of tetrapods. From a functional perspective, the overwhelming evidence of fibrocartilage as a clear response to compression suggests that the fibrocartilaginous patellae could also withstand the mechanical stress generated on the knee undergoing compression during limb extension. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1747–1755, 2017. © 2017 Wiley Periodicals, Inc.     

The Anatomy of Caprine Female Urethra and Characteristics of Muscle and Bone Marrow Derived Caprine Cells for Autologous Cell Therapy Testing

Cell therapy is emerging as an alternative treatment of stress urinary incontinence. However, many aspects of the procedure require further optimization. A large animal model is needed to reliably test cell delivery methods. In this study, we aim to determine suitability of the goat as an experimental animal for testing intraurethral autologous cell transplantation in terms of urethral anatomy and cell culture parameters. The experiments were performed in 12 mature/aged female goats. Isolated caprine muscle derived cells (MDC) were myogenic in vitro and mesenchymal stem cells (MSC) population was able to differentiate into adipo‐, osteo‐ and chondrogenic lineages. The median yield of cells after 3 weeks of culture amounted 47 × 10(6) for MDC and 37 × 10(6) for MSC. Urethral pressure profile measurements revealed the mean functional urethral length of 3.75 ± 0.7 cm. The mean maximal urethral closure pressure amounted 63.5 ± 5.9 cmH₂O and the mean functional area was 123.3 ± 19.4 cm*cmH₂O. The omega‐ shaped striated urethral sphincter was well developed in the middle and distal third of the urethra and its mean thickness on cross section was 2.3 mm. In the proximal part of the urethra only loosely arranged smooth muscle fibers were identified. To conclude, presented data demonstrate that caprine MDC and MSC can be expanded in vitro in a repeatable manner even when mature or aged animals are cell donors. Results suggest that female caprine urethra has similar parameters to those reported in human and therefore the goat can be an appropriate experimental animal for testing intraurethral cell transplantation. Anat Rec, 00:000–000, 2016. © 2016 Wiley Periodicals, Inc. Anat Rec, 300:577–588, 2017. © 2016 Wiley Periodicals, Inc.     

Internal Ophthalmic Arteries Within the Brain‐Base Arterial System in Guinea Pig

In situ vascular specimens of the arterial circle were collected from 15 adult guinea pigs, both male and female. After specimen preparation, the vessels were filled with synthetic latex and subjected to analysis. Similar as in the case of other rodents, vertebral arteries were merged into basilar artery, further dividing into two short terminal branches. Distally, the terminal branches extend into caudal cerebral arteries. Rostral part of the arterial circle of brain is supplied with blood from maxillary arteries via external and internal ophthalmic arteries connected by a short anastomosis. This type of vascularity may probably be considered a functional analogy to the internal carotid arteries observed in other species. Rostral and caudal parts of the arterial circle of brain are connected by exceptionally long caudal communicating arteries. In author's opinion, the disputable contribution of internal carotid artery and the exceptional contribution of internal ophthalmic arteries in the cerebral blood supply in guinea pigs as compared to other rodents, warrants further research on the subject. Anat Rec, 301:887–891, 2018. © 2017 Wiley Periodicals, Inc.