Nikos Solounias

New York Institute of Technology | NYIT · Department of Anatomy

Museum specimens are sometimes misidentified or have been overlooked in taxonomic reassessments. A careful re-examination of such specimens has revealed the occurrence of new Giraffidae in the classic Vallesian and Turolian faunas of the Siwaliks, Pikermi, Samos and Maragheh. Herein, we report the novel occurrences of Vishnutherium iravadicum from...

The giraffe juvenile has different proportions of head to neck from the adult. The head just about doubles in size from the juvenile to adult, whereas the neck increases almost 4.5× (roughly four times) in length. The T1 posterior dorsal vertebral width of the newborn is clearly wider than in the adult where it is narrow. In the okapi, the dorsal v...

Wang et al. (Research Articles, 3 June 2022, eabl8316) reported an early Miocene giraffoid that exhibited fierce head-butting behavior and concluded that sexual selection promoted head-neck evolution in giraffoids. However, we argue that this ruminant is not a giraffoid and thus that the hypothesis that sexual selection promoted giraffoid head-neck...

It has been recognized as early as the Victorian era that the apex of the distal phalanx has a distinct embryological development from the main shaft of the distal phalanx. Recent studies in regenerative medicine have placed an emphasis on the role of the apex of the distal phalanx in bone regrowth. Despite knowledge about the unique aspects of the...

The recovery of a new partial cranium of Decennatherium rex Ríos et al . 2017 bearing two anterior and two posterior ossicones from the Late Miocene deposits of the site Batallones-10 (MN-10, Cerro de los Batallones, Madrid Basin) sheds light on the complex variability of the cranial appendages of these extinct giraffids. The special features of th...

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are provid...

This study deals with the issues around the synonymization of the large extinct giraffid genera Libytherium and Sivatherium. We performed a morphological and biometrical analysis of the cranial remains of these giraffid genera and resolved this question by formulating criteria to distinguish Libytherium from Sivatherium, and to justify their system...

Description of some osteological differences in the tarsal joint between the two giraffes possibly belonging to the species: Giraffa camelopardalis antiquitorum and Giraffa reticulata. This is a pilot study until more individuals are studied. Differences are presented in the fibula, calcaneus, and astragalus. Other bones possess differences but are...

We explored the unusual position, anatomy and evolutionary significance of the position of the horns in Bos taurus. In the genus Bos, the frontal bone, frontal sinus and parietal bones are shifted and repositioned. A new occipital (pseudo-occipital) crest forms at the edge of the calvaria. The true occipital crest has shifted to the back along with...

Evolution has shaped the limbs of hoofed animals in specific ways. In artiodactyls, it is the common assumption that the metatarsal is composed of the fusion of digits III and IV, whereas the other three digits have been lost or are highly reduced. However, evidence from the fossil record and internal morphology of the metatarsal challenges these a...

Palaeontologists have known about the fossiliferous site at Thermopigi (Central Macedonia, N. Greece) for the past two decades. Following the first field campaigns a wealth of new information on the overall geology, taphonomy and palaeontology of the site became available. With more than 1300 fossils, representing at least 20 mammalian species, The...

Previously undescribed remains of a new large giraffid have been identified from the late Miocene Siwaliks Hills of the Potwar Plateau in Pakistan. This taxon is very intimately related to the late Miocene giraffid genus Decennatherium, previously only certainly identified in the Iberian Peninsula, and with some possible remains assigned to Decenna...

The hypsodont crown of Equus and of other hypsodont ungulates has two functions: It is extra crown in the alveolus which erupts and becomes a functional crown that enables the horse to live longer and feed on abrasive foods and the grit. The second functional aspect is that the crown, while it is in the alveolus, acts as a root to support the high...

We are describing and figuring for the first time skulls of Schansitherium tafeli, which are abundant in the Gansu area of China from the Late Miocene. They were animals about the size of Samotherium with shorter necks that had two pairs of ossicones that merge at the base, which is unlike Samotherium. The anterior ossicones consist of anterior lin...

We revisit digit reduction in the horse and propose that all five digits are partially present in the modern adult forelimb. Osteological descriptions of selected tetradactyl, tridactyl and monodactyl equids demonstrate the evolution of the forelimb. Histological, osteological and palaeontological evidence suggest that the Equus distal forelimb ism...

The oldest Giraffa material presently known consists of dental specimens. The oldest post-cranial Giraffa material belongs to the Plio-Pleistocene taxon Giraffa sivalensis, where the holotype is a third cervical vertebra. We describe three non-dental specimens from the Early Late Miocene of the Potwar Plateau, including an 8.1 million year old ossi...

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 anatomi...

New nephron formation (nephrogenesis) ceases in mammals around birth and is completely absent in adults. In contrast, postembryonic nephrogenesis is well documented in the mesonephric kidneys of fishes and amphibians. The transient mesonephros in reptiles (including birds) and mammals is replaced by the metanephros during embryogenesis. Thus, one m...

Monotreme adult kidney histology. (A-B) Adult kidney sections from Tachyglossus aculeatus (short-beaked echidna) obtained from two individual specimens stained with H&E. (C-D) Sections of adult kidney tissue isolated from Ornithorhynchus anatinus (platypus). In all images, the outer cortex and renal capsule are shown. No evidence of nephrogenesis w...

Examples of kidney histology in specimens that did not show evidence of adult nephrogenesis. (A) G. gecko, (B) A. carolinensis, (C) L. burtonis. The specimens of gekkota were limited. Therefore, we believe the negative results are inconclusive. In contrast, of eleven examined specimens of A. carolinensis, none showed evidence of nephrogenesis by hi...

Six2 in Alligator mississippiensis. (A) Amino acid alignment of Six2 proteins from human and American alligator (XM_006272170). Red color indicates identical residues, dashes represent amino acid stretches present in one but not the other species, and blue indicates non-conserved residues. Six2 proteins from human and American alligator share over...

Species collected for analysis with corresponding body mass/length. (DOC)

Lower power images demonstrating new nephron formation in A. mississippiensis. (A) corresponds to higher power images in Fig 2E and 2G, (B) corresponds to Fig 2F. Scale bars = 100 μm. (TIF)

Gross morphology of nephrogenic zones along renal lobes of the adult American alligator. Nephrogenic zones appear as opaque lines running along the periphery of each renal lobe (arrows). Inset: magnification of nephrogenic zones highlight by dotted lines. (TIF)

Lack of Six2 antibody staining in adult kidneys of Anolis carolinensis. (XM_003225172). (A) Negative Six2 antibody staining (compare to Fig 6A and 6J). (B) Wheat germ agglutinin (WGA) staining (used here as a non-specific fluorescent counter-stain). (C) The result of merging (A) and (B). Scale bar = 50 μm. (TIF)

Lower power images demonstrating zones of nephrogenesis (corresponding to Fig 1). (A) A. mississippiensis (Fig 1A), (B) T. scripta (Fig 1B), (C) C. picta (Fig 1C), (D) T. teguxin (Fig 1D), (E) U. aegyptia (Fig 1E), (F) B. constrictor (Fig 1F). Arrows point to zones of nephrogenesis. Scale bar = 100 μm. (TIF)

Many aspects of human head embryology reflect its evolutionary development. The pharyngeal arches, a major component of head development, originally functioned in filter feeding and vascular exchange, which is why each arch has associated vasculature and muscles. The primitive tongue had few-associated muscles and was responsible for simple movemen...

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 geolo...

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 presen...

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...

Description of measurements and characters used to evaluate cervical vertebral specimens

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 cervic...

The supplementary text includes descriptions of the characters used to evaluate elongation of the vertebrae. It also includes a table of the characters and the character state exhibited by each giraffid species, a table of specimens with museum numbers, and a table of ratios and percent of the vertebrae caudal to the foramen transversarium.

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...

We describe a new species of Prolibytherium, P. fusus, sp. nov., from the lower Miocene of Pakistan, thus extending the genus to Asia. Prolibytherium is otherwise known only from Libya. This species differs from Prolibytherium magnieri in several basioccipital and atlanto-occipital morphologies. Namely, the posterior basioccipital tuberosities are...

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 comprehensiv...

The peripheral nervous system is a promising resource for testing phylogeny although the branching patterns of peripheral nerves are not well documented outside of Homo sapiens. Here we describe the brachial plexus of the rare Sumatran rhinoceros (Dicerorhinus sumatrensis). We compare its brachial plexus to that of another perissodactyl (Equus asin...

2014: A new method of tooth mes-owear and a test of it on domestic goats. — Ann. Zool. Fennici 51: 111–118. 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 brows-ing and a grazing diet. The enamel band of browsers is flat and planar, in...

The bovid faunas of the Siwaliks (Pakistan) show little change in structure or higher level taxonomy through much of the Middle and Late Miocene. Species of Bovinae and Antilopinae are abundant and Caprinae very rare.

Excavations at Kalodirr and Moruorot from the Lothidok Formation (ca. 17 mya) in the West Turkana Region of Kenya have yielded several cranial appendages, dentitions and postcranial fossils that can be attributed to either Climacoceratidae or the Giraffidae. An additional unusual and unique fossil, we describe in this paper for the first time, is,...

While the identity and validity of the extant families of ruminants are undoubted, there are significant problems with the determination of the interrelationships among the families, notably within the families of the Pecora, or horned ruminants. The morphological features used to construct ruminant phylogeny have been a source of controversy: many...

In this study, we use tooth mesowear analysis to compare the paleodietary patterns of the classic Late Miocene faunas of Pikermi and Samos from Greece to those of China. A new scale is used for evaluating mesowear, a technique that uses the sharpness of molar cusp apices as a proxy for dietary abrasion. Details of this mesowear scale can be found i...

This book is devoted to the late Cenozoic (Neogene) mammalian biostratigraphy and geochronology of Asia. It employs cutting-edge biostratigraphic and geochemical dating methods to map the emergence of mammals across the continent. Written by specialists working in a variety of Asian regions, it uses data from fossil records to establish a geochrono...

Cadaver‐based human anatomy courses traditionally dissect the brachial plexus (BP) through the axilla. This approach fails to expose the proximal and posterior parts of the BP. In contrast, non‐human BP dissections use a subscapular approach that exposes the entire BP, from roots to branches. Using four human cadavers, we developed a subscapular ap...

The diets of Procapra gutturosa (Mongolian gazelle) and Pantholops hodgsoni (Tibetan antelope) are investigated through premaxillary shape, mesowear, and microwear analyses. The objective of the study is to test the hypothesis that the two species have similarities in dietary habits and also similarities with arctic or subarctic ungulates such as m...

The late Tortonian – early Messinian shallow marine sands of Cessaniti area (Monte Poro, Vibo Valentia, Southern Italy) yield marine and continental vertebrates. The best represented taxon is the Sirenian Metaxytherium serresii, while the terrestrial mammal assemblage includes a boselafine bovid, an hexaprotodontid hippopotamus, the giraffids Samot...

The existence of a land connection between the Monte Poro – Capo Vaticano area (Southern Italy) and North Africa has been firstly suggested by the occurrence of Stegotetrabelodon syrticus at Cessaniti (Ferretti et al., 2003). The newly recorded occurrence of the giraffids Bohlinia cf. attica and Samotherium cf. boissieri (Marra et al., in press) re...

The evolution of high-crowned molars among horses (Family Equidae) is thought to be an adaptation for abrasive diets associated with the spread of grasslands. The sharpness and relief of the worn cusp apices of teeth (mesowear) are a measure of dietary abrasion. We collected mesowear data for North American Equidae for the past 55.5 million years t...

A large sample of the Pikermi and Samos ungulates was examined by microwear analysis using a light stereomicroscope (561 extinct and 809 extant comparative specimens). The results were used to infer the dietary adaptations of individual species and to evaluate the Pikermian Biome ungulate fauna. Many of the bovids have wear consistent with mixed fe...

Camels originated in North America in the middle Eocene (Uintan land mammal age) and the first 36 million years of their history is confined to that continent. They were a highly successful group in which some 95 species and thirty-six genera were distributed between five subfamilies: Stenomylinae, Floridatragulinae, Miolabinae, Protolabinae, and C...

The extant giraffes are an iconic part of the African biota, their large size and elongate legs and neck providing an unmistakable silhouette against the African landscape. Their close relatives, the okapis, were among the latest of the large terrestrial mammals to be documented scientifically and are similarly iconic in terms of their rarity and c...

The paleodietary ecology of Late Pleistocene ungulate faunas of the Mammoth Steppe ecosystem was investigated at Fairbanks (Alaska) and Brown Bank (North Sea) through dental mesowear and microwear analysis. The purpose of the study is to address questions concerning the paleoecology of the Mammoth Steppe, an ecosystem that has no extant analog. Den...

In the last few decades, dietary ecological reconstructions have been used as powerful tools in gaining insight into local and global environmental trends. Ungulate mesowear and microwear studies in particular serve as useful proxies for demonstrating the existence of geographical and/or temporal variability in diet and vegetation structure. Improv...

A new and greatly simplified methodology for the assessment of the dietary adaptations of living and fossil taxa has been developed which allows for microwear scar topography to be accurately analyzed at low magnification (35×) using a standard stereomicroscope. In addition to the traditional scratch and pit numbers, we introduce four qualitative v...

A separation exists between the tooth microwear of extant ruminant browsers and grazers when examined with new statistical techniques such as the dichotomous, polychotomous and continuous methods. Extant mixed feeders, however, could not be discerned as a distinct group. Many variables were used in the analysis, including two new variables; the are...

The current consensus is that only one type of horn, the ossicone, exists in the giraffe and that the central or median horn is both structurally and developmentally similar to the paired parietal horns. We have shown that the paired ossicones are composites of three structures: an innermost large frontoparietal boss base, the ossicone, and outermo...

The fossil hyaenids from Langebaanweg in South Africa are revised taxonomically using both morphological comparisons and measurement data. Ictilherium preforfex is found to be a synonym of Ikelohyaena abronia. Other hyaenid taxa in this fauna are Hyaenictitherium namaquensis, Chasmaporthetes australis and a new taxon similar to Chasmaporthetes aust...

Material of the Miocene hyaenid Adcrocuta eximia from China is analysed statistically. No heterogeneities were found within this material. Comparisons with material from Samos and Pikermi, Greece, show that no taxonomic differentiation between these three samples is warranted. Adcrocuta eximia latro from the Sivalik deposits is provisionally consid...

During the late Pleistocene and early Holocene, Bison was widely dispersed across North America and occupied most regions not covered by ice sheets. A dietary study on Bison paleopopulations from Alaska, New Mexico, Florida, and Texas was performed using two methods that relate dental wear patterns to diet, mesowear analysis and microwear analysis....

Extant ungulates can be divided into three dietary categories: browsing feeders, grazing feeders, and mixed feeders. Dietary adaptations can be differentiated in extinct ruminants based upon tooth microwear analysis as well as evaluation of premaxillary morphology. Tooth microwear shows that the extinct bovid Kipsigicerus labidotus from the Miocene...

Tooth microwear was analyzed for a large sample of wild-shot barren-ground caribou (Rangifer tarandus groenlandicus) from the Kaminuriak population of eastern Canada. This sample was compared to the microwear of specimens from three Pleistocene localities in North America (Alaska) and western Europe (Caune de l’Arago in France and Salzgitter in Ger...

This second part of our field trip guide deals with the Miocene fossils found near Mytilini. Those fossils have already been interpreted by some of the Greek philosophers and are the main reason why Samos is a famous island for Earth Scientists.

The evolution of increased tooth crown height is considered to be an adaptation for coping with excessive rates of dental wear associated with abrasive herbivorous diets, such as grazing and(or high levels of exogenous grit (e.g. dust, sand, ash). Evolutionary trends in the crown heights of North American ungulates are grossly consistent with a tra...

The diet of Mongolian gazelles and Tibetan antelopes is subject to discussion. Mongolian gazelles (Procapra gutturosa) are classified either as grazers or mixed feeders, whereas Tibetan antelopes are known to be browsers or mixed feeders. The diet of these two ungulates is evaluated in this study by dental microwear (i.e., immediate wear) and mesow...

A large sample (N = 76) of Pleistocene mastodon (Mammut americanum) teeth from a variety of localities in Florida were analyzed for dental enamel microwear features via low-magnification stereomicroscopy. Second upper and lower molars were used for dental dietary reconstruction purposes to allow comparison of results to an extensive molar microwear...

The dietary preference of Sivatherium hendeyi (Harris, 1976), an extinct giraffid from the early Pliocene of South Africa, was investigated by applying three dietary reconstruction tools - hypsodonty, mesowear and microwear. The hypsodonty index for S. hendeyi is 1.51 ± 0.06, which is within the brachyodont category as in most ruminant browsers. Th...

A new method of scoring dental microscopic use wear, initially developed for and applied to extant and extinct ungulates, is here applied to primates, and the efficacy of the method as a tool for diagnosing diet in both ungulates and primates is established. The method employs standard refractive light microscopy instead of scanning electron micros...