New anomalies and pathologies in the caudal region of the lizard’s axial skeleton

Currently, more than 58 skeletal anomalies and pathologies are known in the recent Squamata reptiles. In this paper, eight pathologies of a complex nature are described in Agamidae and Lacertidae: Paralaudakia caucasia (Eichwald, 1831) and Lacerta agilis Linnaeus, 1758. Description of tail pathologies was carried out based on the analysis of X-ray images and on the results of computer microtomography. In the specimen of P. caucasia (ЗИН 19116.1) complete ablation of the caudal vertebra was revealed, which provoked the detachment of chevron and the proliferation of soft tissues. In some Agamidae, after pseudoautotomy, partial ablation of the caudal vertebra occurs to promote wound healing. Complete ablation of the distal caudal vertebra has not been previously reported in literature. In females of L. agilis, deformation of the right transverse process of the vertebra with “false bifurcation” without the formation of a cartilaginous tube (VOLSU 98.2), scoliosis, hematoma and callus on the cartilaginous tube were noted, as well as the absence of an autotomy plane in the postpygal vertebra (ZIN 31549). An unusual pathology in L. agilis (ZIN 31549) is the absence of an autotomy plane in the postpigal vertebra and of its anterior neural spine. The loss of the plane of autotomy during ontogeny is characteristic of some Iguanidae, but it has not been previously noted in Lacertidae. The described cases of anomalies expand the spectrum of known pathologies in reptiles.

The cranial anatomy and relationships of Cardiocorax mukulu (Plesiosauria: Elasmosauridae) from Bentiaba, Angola

We report a new specimen of the plesiosaur Cardiocorax mukulu that includes the most complete plesiosaur skull from sub-Saharan Africa. The well-preserved three-dimensional nature of the skull offers rare insight into the cranial anatomy of elasmosaurid plesiosaurians. The new specimen of Cardiocorax mukulu was recovered from Bentiaba, Namibe Province in Angola, approximately three meters above the holotype. The new specimen also includes an atlas-axis complex, seventeen postaxial cervical vertebrae, partial ribs, a femur, and limb elements. It is identified as Cardiocorax mukulu based on an apomorphy shared with the holotype where the cervical neural spine is approximately as long anteroposteriorly as the centrum and exhibits a sinusoidal anterior margin. The new specimen is nearly identical to the holotype and previously referred material in all other aspects. Cardiocorax mukulu is returned in an early-branching or intermediate position in Elasmosauridae in four out of the six of our phylogenetic analyses. Cardiocorax mukulu lacks the elongated cervical vertebrae that is characteristic of the extremely long-necked elasmosaurines, and the broad skull with and a high number of maxillary teeth (28–40) which is characteristic of Aristonectinae. Currently, the most parsimonious explanation concerning elasmosaurid evolutionary relationships, is that Cardiocorax mukulu represents an older lineage of elasmosaurids in the Maastrichtian.

Comparative osteology of three endemic cichlids (Iranocichla spp.) (Actinopterygii, Perciformes, Cichlidae) from southern Iran

Iranian cichlids are isolated disjunct populations of the African cichlids group, restricted to the Hormuz Strait region in the Hormuz basin, and are a very important group from both zoogeographic and phylogenetic points of view. Thus, the osteological structures, as one of the most reliable structures, of the three nominal species of Iranian cichlid fishes, Iranocichla hormuzensis Coad, 1982, from the Mehran River, Iranocichla persa Esmaeili, Sayyadzadeh et Seehausen, 2016, from Khorgo hot spring, and Iranocichla sp., from the Kol River were described and compared. Ten specimens of each species were cleared and stained with Alcian blue and Alizarin red. A digital camera was used for taking pictures and CorelDraw X6 software for preparing drawings. The three species have some differences in the caudal fin skeleton, shape of the urostyle, neural spine of preural 2, hypural spines 2, and 3, anterior part of parhypural and hypurapophysis, the size of neural spines of preural 2 and 3, hypural 3 and 4, and epurals. Although there are some differences among the species, osteology of these species is very conservative and other traits like behavioral and molecular should be used.

First rebbachisaurid sauropod dinosaur from Asia

Dzharatitanis kingi gen. et sp. nov. is based on an isolated anterior caudal vertebra (USNM 538127) from the Upper Cretaceous (Turonian) Bissekty Formation at Dzharakuduk, Uzbekistan. Phylogenetic analysis places the new taxon within the diplodocoid clade Rebbachisauridae. This is the first rebbachisaurid reported from Asia and one of the youngest rebbachisaurids in the known fossil record. The caudal is characterized by a slightly opisthocoelous centrum, ‘wing-like’ transverse processes with large but shallow PRCDF and POCDF, and the absence of a hyposphenal ridge and of TPRL and TPOL. The neural spine has high SPRL, SPDL, SPOL, and POSL and is pneumatized. The apex of neural spine is transversely expanded and bears triangular lateral processes. The new taxon shares with Demandasaurus and the Wessex rebbachisaurid a high SPDL on the lateral side of the neural spine, separated from SPRL and SPOL. This possibly suggests derivation of Dzharatitanis from European rebbachisaurids. This is the second sauropod group identified in the assemblage of non-avian dinosaurs from the Bissekty Formation, in addition to a previously identified indeterminate titanosaurian.

Gross Morphological Studies on the Vertebral Column of Indian Eagle Owl (Bubo bengalensis)

Background: Indian eagle owl known to rotate their necks up to 270 degrees in either direction without injuring their vessels running below the head thereby without cutting off blood supply to their brains. The vertebral column in birds carry peculiar features like higher number of cervical vertebrae due to long mobile neck, lumbar and sacral vertebrae fused together giving rigidity which aid in flight. The extensive fusion of vertebral column posterior to the neck provides the required rigidity in the trunk region, this inflexibility feature might reduce weight, as it avoids the need for extensive musculature to maintain a streamlined and rigid body posture during flight. The current study aimed to study the vertebral column of Indian eagle owl in order to understand the anatomical adaptations related to this species. Methods: The specimens were procured from three Indian eagle owl brought for post mortem examination during the year 2019 to the Department of Veterinary Pathology, Rajiv Gandhi Institute of Veterinary Education and Research, Puducherry. After completion of the post-mortem examination the carcass was collected and macerated as per the standard technique and various measurements on vertebral column bones were measured using vernier calliper. Result: The study revealed that vertebral column of Indian eagle owl consisted of 14 cervical vertebrae, 7 thoracic vertebrae, 13 to 14 lumbar vertebrae fused with sacral vertebrae forming synsacrum and 7 coccygeal vertebrae. The hypapophyses of the 14th cervical vertebra and first two thoracic vertebrae were trifid in nature specific feature seen in Indian eagle owl. The vertebral column had characteristics features of hypapophyses, transverse process, pneumatic foramen and neural spine which enable the owl to adapt for head rotation and various task involving vertebrae.

Comparative osteology of Tor tambroides (Bleeker, 1854) and Tor tambra (Valenciennes 1842) vertebral column (ossa vertebrae)

Information related to osteology plays a vital role in support ecomorphology and phylogenetic relationship analysis in fish. This study aimed to describe the comparative morphology of the vertebral column between Tor tambroides (Bleeker, 1854) and Tor tambra (Valenciennes 1842). Samples of Tor tambroides and Tor tambra were obtained from fish traders in the Tangse River area of Pidie Regency and Sampoinet River area, Aceh Jaya Regency, Aceh Province. Vertebral column preparation consists of five steps: muscles and scales separation, immersion in a formaldehyde solution, drying, morphometric measurements, photographing and image editing, and identification of terminology. The results showed that there are morphological differences between Tor tambroides and Tor tambra vertebral column, particularly in the axial vertebrae, posterior vertebrae caudales, and urostylus regions. The pleural costae of Tor tambroides have a posterior curve with the left and right sides interlocking. The lateral Tor tambroides process tends to curve posteriorly, while the Tor tambra tends to round up parallel to the dorsal costae. Tor tambroides tend to have stronger ligaments marked by the absence of a foramen between the hypural. Morphometrically, Tor tambroides tend to have higher centrum ratios (length, width, and height), neural spine, haemalis spine, and costae compared to Tor tambra. The significant difference in morphometric results in observed the axial vertebrae and the posterior vertebrae caudales region. Further research related to the correlation of vertebral column morphology with the environmental condition of these fish is still necessary.

Earliest North American articulated freshwater acanthomorph fish (Teleostei: Percopsiformes) from Upper Cretaceous deposits of Alberta, Canada

Fossil material from the Maastrichtian part of the Scollard Formation is identified as belonging to an acanthomorph fish. An articulated specimen, preserved in part and counterpart, is a member of the paracanthopterygian order Percopsiformes, based on it having a full neural spine on the second preural centrum and two epurals in the caudal skeleton (both paracanthopterygian characters), as well as six branchiostegal rays and an anterodorsal excavated margin on the opercle (percopsiform characters). We name this as a new genus and species, Lindoeichthys albertensis. A phylogenetic analysis with no prior constraints recovered a single most-parsimonious tree with the new taxon placed as the sister group to a clade containing the Palaeocene Montana genus Mcconichthys + Percopsidae. However, this analysis did not recover the traditional percopsiforms (including Aphredoderidae and Amblyopsidae) as monophyletic. A second analysis, in which we constrained the traditional members of the Percopsiformes to be monophyletic, resulted in the new species being placed as the sister group to Percopsis. The articulated percopsiform specimen from the Pisces Point locality allows isolated dentaries from vertebrate microfossil localities to be identified as being from a member of that group. These isolated elements first appear in the late Campanian Judith River Group of Alberta and the Kaiparowits Formation of Utah, documenting that percopsiform fishes were present in the Western Interior of North America at least 75 Ma ago.

New Information on the Madagascan Middle Jurassic Sauropod Lapparentosaurus madagascariensis

The systematic position of the Middle Jurassic sauropod Lapparentosaurus madagascariensis is not fully understood due to a lack of useful anatomical detail. Despite many new bone fragments from the axial skeleton, post-cranial skeleton, and a hind limb having been previously unearthed, its systematic position has not yet been satisfactorily established. Although this Malagasy taxon is only recognised by two autapomorphies located in the scapula and coracoid, two features of the neural spine, which are reported here, provide additional information on the common autapomorphies shared with the British genus Cetiosaurus. A full description of the femur and neural spine helps to determine some aspects of its relationship to other similar taxa. Remains of Lapparentosaurus madagascariensis have been recovered from mixed facies that may have been deposited in a shallow water lagoon during a transgressive period in the Isallo IIIb subunit in the Majunga Basin.

Intraspecific male combat behaviour predicts morphology of cervical vertebrae in ruminant mammals

Cranial weapons of all shapes and sizes are common throughout the animal kingdom and are frequently accompanied by the evolution of additional traits that enhance the use of those weapons. Bovids (cattle, sheep, goats, antelope) and cervids (deer) within the mammal clade Ruminantia are particularly well known for their distinct and varied cranial appendages in the form of horns and antlers, which are used as weapons in intraspecific combat between males for access to mates. Combat in these species takes many forms, including head-on collisions (ramming); stabbing an opponent's head or body with horn tips (stabbing); rearing and clashing downwards with horns (fencing); or interlocking antlers or horns while vigorously pushing and twisting (wrestling). Some aspects of weapon and skull morphology have been linked to combat behaviours in bovid and cervid species, but the contribution of postcranial structures that support these weapons, such as the neck, has not been explored. To investigate the role of the neck in intraspecific combat, we quantified biomechanically relevant linear variables of the cervical vertebrae (C1–C7) from males and females of 55 ruminant species. We then used phylogenetic generalized least-squares regression to assess differences among species that display primarily ramming, stabbing, fencing and wrestling combat styles. In males, we found that wrestlers have longer vertebral centra and longer neural spines than rammers, stabbers or fencers, while rammers have shorter and wider centra and taller neural spine lever arms. These results suggest a supportive role for the cervical vertebrae in resisting forces generated by male–male combat in ruminant mammals and indicate that evolutionary forces influencing cranial weapons also play a role in shaping the supporting anatomical structures.