Melinda Danowitz

Fossil evidence and stages of elongation of the Giraffa camelopardalis neck

Several evolutionary theories have been proposed to explain the adaptation of the long giraffe neck; however, few studies examine the fossil cervical vertebrae. We incorporate extinct giraffids, and the okapi and giraffe cervical vertebral specimens in a comprehensive analysis of the anatomy and elongation of the neck. We establish and evaluate 20 character states that relate to general, cranial and caudal vertebral lengthening, and calculate a length-to-width ratio to measure the relative slenderness of the vertebrae. Our sample includes cervical vertebrae (n=71) of 11 taxa representing all seven subfamilies. We also perform a computational comparison of the C3 of Samotherium and Giraffa camelopardalis, which demonstrates that cervical elongation occurs disproportionately along the cranial–caudal vertebral axis. Using the morphological characters and calculated ratios, we propose stages in cervical lengthening, which are supported by the mathematical transformations using fossil and extant specimens. We find that cervical elongation is anisometric and unexpectedly precedes Giraffidae. Within the family, cranial vertebral elongation is the first lengthening stage observed followed by caudal vertebral elongation, which accounts for the extremely long neck of the giraffe.

A New Method of Tooth Mesowear and a Test of it on Domestic Goats

Mesowear III is a new form of mesowear that uses separately the mesial and distal surfaces of enamel band 2 of the upper second molar to differentiate between a browsing and a grazing diet. The enamel band of browsers is flat and planar, in grazers it contains gouges and sub-facets which eventually become round. Mesowear III scores these shapes on a scale 1–4; score 1 represents the typical browser and score 4 represents a typical grazer. Differences in diet can also be studied by observing the junction between the mesial and distal side of the enamel band (j point); the j point is sharper and well defined in browsers, while it is rounder or non-existent in grazers. Wild browsers, grazers, and mixed feeders separate well using mesowear III. The wild taxa data were similar to mesowear III of experimental goats that were fed a controlled grazing or browsing diet (species of plants known). In addition, the browsing versus the grazing goat mesowear III signal becomes more distinct from each other by 40 days of feeding. Mesowear III so far gives a finer signal than previous mesowear (I and II).

The Cervical Osteology of Okapia johnstoni and Giraffa camelopardalis

Giraffidae is the only family of ruminants that is represented by two extant species; Okapia johnstoni and Giraffa camelopardalis. Of these taxa, O. johnstoni represents a typical short-necked ungulate, and G. camelopardalis exemplifies the most extreme cervical elongation seen in any ruminant. We utilize these two species to provide a comprehensive anatomic description of the cervical vertebrae. In addition, we compare the serial morphologic characteristics of the okapi and giraffe cervical vertebrae, and report on several osteologic differences seen between the two taxa. The giraffe neck appears to exhibit homogenization of C3-C7; the position of the dorsal tubercle, thickness of the cranial articular process, shape of the ventral vertebral body, and orientation of the ventral tubercle are constant throughout these vertebrae, whereas these features are serially variable in the okapi. We also report on several specializations of the giraffe C7, which we believe relates to an atypical cervico-thoracic junction, corresponding to the substantial neck lengthening. The morphologic differences exhibited between the okapi and giraffe cervical vertebrae have implications on the function of the necks relating to both fighting and feeding.

The Giraffidae of Maragheh and the identification of a new species of Honanotherium

Giraffids were important components of the late Miocene Maragheh mammalian community. We provide detailed cranial and post-cranial morphological descriptions of six Maragheh giraffids, including Helladotherium duvernoyi, Alcicephalus neumayri, Samotherium boissieri, Samotherium major, Palaeotragus coelophrys and Bohlinia attica, extending the geological range of several taxa. We also describe a new species of Honanotherium (Honanotherium bernori), a taxon smaller than Honanotherium schlosseri. This is the westernmost occurrence of Honanotherium. We create our giraffid faunal list by first identifying each Maragheh specimen to a species, creating a representative specimen/species list. Subsequently, each specimen is described by comparing the Maragheh elements with the corresponding specimens from the type locality where each species is originally known. This method allows for accurate species identifications, and facilitates palaeoecological comparisons between multiple localities using morphological differences in the taxa. For palaeoecology, we evaluate and analyse the dentition of a few adult Maragheh giraffids using combined inner and outer mesowear variables, and find individuals spanning the dietary continuum, but with a polarity towards browsing diets. We describe limb differences among the Palaeotraginae, describe dental and limb similarities between Helladotherium duvernoyi and species of Bohlininae, and discuss the ossicones of Bohlininae. We provide comprehensive and detailed anatomical descriptions of seven giraffid taxa that can facilitate future species identifications and comparisons.

The cervical anatomy of Samotherium, an intermediate-necked giraffid

Giraffidae are represented by many extinct species. The only two extant taxa possess diametrically contrasting cervical morphology, as the okapi is short-necked and the giraffe is exceptionally long-necked. Samotherium major, known from the Late Miocene of Samos in Greece and other Eurasian localities, is a key extinct giraffid; it possesses cervical vertebrae that are intermediate in the evolutionary elongation of the neck. We describe detailed anatomical features of the cervicals of S. major, and compare these characteristics with the vertebrae of the two extant giraffid taxa. Based on qualitative morphological characters and a quantitative analysis of cervical dimensions, we find that the S. major neck is intermediate between that of the okapi and the giraffe. Specifically, the more cranial (C2–C3) vertebrae of S. major represent a mosaic of features shared either with the giraffe or with the okapi. The more caudal (C5–C7) S. major vertebrae, however, appear transitional between the two extant taxa, and hence are more unique. Notably, the C6 of S. major exhibits a partially excavated ventral lamina that is strong cranially but completely absent on the caudal half of the ventral vertebral body, features between those seen in the giraffe and the okapi. Comprehensive anatomical descriptions and measurements of the almost-complete cervical column reveal that S. major is a truly intermediate-necked giraffid. Reconstructions of the neck display our findings.

First comprehensive morphological analysis on the metapodials of Giraffidae

Giraffids are a group of relict pecoran ruminants with only two living taxa. During the Miocene, however, this group was much more diverse, with more than 20 different species showing a wide range of variability. In addition to many other parts of the skeleton this variability is also represented in their metapodials. We find inter-specific anatomical differences in the giraffid metapodials; each taxon evaluated possesses a unique combination of limb morphologies. The proximo-palmar/plantar metapodial surface provides useful characteristics and allows for genus identifications and comparisons. We describe the central trough of the metapodial shaft; when combined with the absolute length of the limb, the depth of this trough allows for better separation between taxa. We find that the metacarpal robustness index exceeds that of the metatarsals in all except one giraffid evaluated, supporting a front-loaded body weight distribution, consistent with the elongated cervicals or large ossicones seen in many taxa. The morphological features of the giraffid metapodials, as well as the limb lengths and proportions can be a useful tool for phylogenetic analysis. Maria Rios. Departamento de Paleobiología, Museo Nacional de Ciencias Naturales-Consejo Superior de Investigaciones Científicas, 2 Gutiérrez Abascal, Madrid, 28006, Spain. maria.rios.iba@mncn.csic.es Melinda Danowitz. Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, 8000 Northern Boulevard, Old Westbury, NY 11568, USA. mdanowit@nyit.edu Nikos Solounias. Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, 8000 Northern Boulevard, Old Westbury, NY 11568, USA. And Department of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA. nsolouni@nyit.edu

Astragalar Morphology of Selected Giraffidae

The artiodactyl astragalus has been modified to exhibit two trochleae, creating a double pullied structure allowing for significant dorso-plantar motion, and limited mediolateral motion. The astragalus structure is partly influenced by environmental substrates, and correspondingly, morphometric studies can yield paleohabitat information. The present study establishes terminology and describes detailed morphological features on giraffid astragali. Each giraffid astragalus exhibits a unique combination of anatomical characteristics. The giraffid astragalar morphologies reinforce previously established phylogenetic relationships. We find that the enlargement of the navicular head is a feature shared by all giraffids, and that the primitive giraffids possess exceptionally tall astragalar heads in relation to the total astragalar height. The sivatheres and the okapi share a reduced notch on the lateral edge of the astragalus. We find that Samotherium is more primitive in astragalar morphologies than Palaeotragus, which is reinforced by tooth characteristics and ossicone position. Diagnostic anatomical characters on the astragalus allow for giraffid species identifications and a better understanding of Giraffidae.

Embryology and evolutionary history of the respiratory tract

Human respiratory embryology and anatomy often reflects the evolutionary transformation from primitive breathing apparatuses. The gills of fishes are invested with vasculature, muscles, cartilages and nerves, and function in pumping water to facilitate gas exchange. As tetrapods evolve air-breathing respiratory structures, the gills lose their breathing function. However, the associated arteries, veins, nerves, musculature, and cartilaginous support become integrated into the pharynx and head. In the Tiktaalik, a popular proposed transitional species between fishes and tetrapods, both gills and lungs are present. Variations in the anatomy of the larynx allow for differing methods of sound production between birds, reptiles, and mammals, and the changing position of the larynx in humans represents feeding mechanisms in infants, and voice production in adults. Comprehension of the normal embryologic development also facilitates a deeper understanding of congenital anomalies. The respiratory tree originates as a diverticulum off of the proximal endodermal gut tube; failed septation between the lung buds and digestive Samantha White1, Melinda Danowitz1, Nikos Solounias2 Affiliations: 1Medical Student, Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA; 2Professor, Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA. Corresponding Author: Melinda Danowitz 8000 Northern Boulevard Old Westbury NY, USA, 11568; E-mail: mdanowit@nyit.edu Received: 28 May 2016 Accepted: 28 June 2016 Published: 21 July 2016 tract results in an anomalous respiratory/ esophageal connection seen in tracheoesophageal fistulas. Combining key features of human lung embryology with comparative respiratory anatomy reinforces the relationship between structure and function, and will facilitate a deeper comprehension of lung development.

Embryology, comparative anatomy, and congenital malformations of the gastrointestinal tract

Evolutionary biology gives context to human embryonic digestive organs, and demonstrates how structural adaptations can fit changing environmental requirements. comparative anatomy is rarely included in the medical school curriculum. However, its concepts facilitate a deeper comprehension of anatomy and development by putting the morphology into an evolutionary perspective. Features of gastrointestinal development reflect the transition from aquatic to terrestrial environments, such as the elongation of the colon in land vertebrates, allowing for better water reabsorption. In addition, fishes exhibit ciliary transport in the esophagus, which facilitates particle transport in water, whereas land mammals develop striated and smooth esophageal musculature and utilize peristaltic muscle contractions, allowing for better voluntary control of swallowing. the development of an extensive vitelline drainage system to the liver, which ultimately creates the adult hepatic portal system allows for the evolution of complex hepatic metabolic functions seen in many vertebrates today. Melinda Danowitz1, Nikos Solounias2 Affiliations: 1B.A, Medical Student, Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA; 2PhD, Professor, Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA. Corresponding Author: Melinda Danowitz, 8000 Northern Boulevard, Old Westbury, NY, USA, 11568; Email: mdanowit@nyit.edu Received: 19 April 2016 Accepted: 31 May 2016 Published: 18 June 2016 Human digestive development is an essential topic for medical students and physicians, and many common congenital abnormalities directly relate to gastrointestinal embryology. We believe this comprehensive review of gastrointestinal embryology and comparative anatomy will facilitate a better understanding of gut development, congenital abnormalities, and adaptations to various evolutionary ecological conditions.

Right sided diaphragmatic hernia of Morgagni with associated anatomical abnormalities

At New York Institute of Technology College of Osteopathic Medicine, a rare type of diaphragmatic hernia has been observed within a cadaver in the Anatomy department during routine dissections. Normally, congenital diaphragmatic hernias appear on the left side, namely a Bochdalek hernia. This particular hernia, a Morgagni type, is uniquely found on the anterior right side of the thorax. This 101yearold female cadaveric specimen had a herniation of the greater omentum, stomach, and portion of the duodenum into the right side of the thorax, with an associated slight mediastinal shift to the left. In addition, this cadaver had a fleshy ‘string’ of tissue connecting the hernia sac to the sigmoid colon, a tortuous internal carotid artery, thickened costal cartilages, and weak fascia.