Kukri snakes Oligodon Fitzinger, 1826 of the Western Palearctic with the resurrection of Contia transcaspica Nikolsky, 1902 (Reptilia, Squamata, Colubridae).

The kukri snakes of the genus Oligodon Fitzinger, 1826 reach the westernmost limits of their distribution in Middle and Southwest Asia (Afghanistan, Iran, and Turkmenistan), and the Palearctic portions of Pakistan. In this article, we review the systematics and distribution of the two species native to this region, Oligodon arnensis (Shaw, 1802) and Oligodon taeniolatus (Jerdon, 1853) based on an integrative approach combining morphological, molecular, and species distribution modeling (SDM) data. Phylogenetic analyses recover O. taeniolatus populations from Iran and Turkmenistan in a clade with the O. arnensis species complex, rendering the former species paraphyletic relative to O. taeniolatus sensu stricto on the Indian subcontinent. To correct this, we resurrect the name Contia transcaspica Nikolsky, 1902 from the synonymy of O. taeniolatus and assign it to populations in Middle-Southwest Asia. So far, Oligodon transcaspicus comb. et stat. nov. is known only from the Köpet-Dag Mountain Range of northeast Iran and southern Turkmenistan, but SDM mapping suggests it may have a wider range. Genetic samples of O. "arnensis" from northern Pakistan are nested in a clade sister to the recently described Oligodon churahensis Mirza, Bhardwaj & Patel, 2021, and are phylogenetically separate from O. arnensis sensu stricto in south India and Sri Lanka. Based on morphological similarity, the Afghanistan and Pakistan populations are assigned to Oligodon russelius (Daudin, 1803) and we synonymize O. churahensis with this species. Our investigation leads us to remove O. taeniolatus from the snake fauna of Afghanistan, Iran, and Turkmenistan, with the consequence that only Oligodon transcaspicus comb. et stat. nov. and O. russelius are present in these countries. Additional studies are needed to resolve the taxonomy of the O. taeniolatus and O. arnensis species complexes on the Indian subcontinent, and an updated key for both groups is provided.

Identifying high snakebite risk area under climate change for community education and antivenom distribution.

Snakebite is one of the largest risks from wildlife, however little is known about venomous snake distribution, spatial variation in snakebite risk, potential changes in snakebite risk pattern due to climate change, and vulnerable human population. As a consequence, management and prevention of snakebite is hampered by this lack of information. Here we used habitat suitability modeling for 10 medically important venomous snakes to identify high snakebite risk area under climate change in Iran. We identified areas with high snakebite risk in Iran and showed that snakebite risk will increase in some parts of the country. Our results also revealed that mountainous areas (Zagros, Alborz, Kopet-Dagh mountains) will experience highest changes in species composition. We underline that in order to improve snakebite management, areas which were identified with high snakebite risk in Iran need to be prioritized for the distribution of antivenom medication and awareness rising programs among vulnerable human population.

Comparison of the debonding force of metal, glass and polyethylene Fiber reinforced composite retainers: Mechanical and finite element analyses.

OBJECTIVE: The studies evaluating the efficiency of fiber reinforce composite (FRC) retainers are few and contradictory. This study aimed to compare the debonding force of metal, glass FRC (GFRC) and polyethylene FRC (PFRC) retainers, assess the interactions between the materials and forces, and pattern of load distribution by finite element analysis (FEA). MATERIALS AND METHODS: Forty-eight sound lower incisors were collected and randomly assigned to 3 groups (n=8; each sample included 2 teeth). Next, 15mm of the three retainers (multi-stranded metal wire, GFRC, and PFRC) were bonded to the lingual surface of the teeth and debonding force was measured by a universal testing machine. For FEA, 3D models were designed. The data related to geometrical models and material properties were transferred to ANSYS software. A 187-Newton load was applied to the incisal edge of the two centrals. Then different parameters were assessed. The three groups were compared by one-way Anova and Tukey's test. Type one error was considered to be 0.05. RESULTS: The debonding force decreased in the order: Metal (143.71N)≥GFRC (108.29N)>PFRC (45.08N). The difference between metal retainer and GFRC was not significant. In contrast, PFRC group showed significantly lower debonding force compared to other groups (P<0.05). FEA showed stress peak value in metal-composite interface. Maximum total deformation was noted in central, followed by lateral and canine. CONCLUSIONS: Glass-FRC can serve as an alternative to metal retainers as the difference in debonding force is not significant. However, the difficulty of repairing or replacing the Glass-FRC should be taken into account given the large number of failure in the interproximal dental area.

A comparative study on image-based snake identification using machine learning.

Automated snake image identification is important from different points of view, most importantly, snake bite management. Auto-identification of snake images might help the avoidance of venomous snakes and also providing better treatment for patients. In this study, for the first time, it's been attempted to compare the accuracy of a series of state-of-the-art machine learning methods, ranging from the holistic to neural network algorithms. The study is performed on six snake species in Lar National Park, Tehran Province, Iran. In this research, the holistic methods [k-nearest neighbors (kNN), support vector machine (SVM) and logistic regression (LR)] are used in combination with a dimension reduction approach [principle component analysis (PCA) and linear discriminant analysis (LDA)] as the feature extractor. In holistic methods (kNN, SVM, LR), the classifier in combination with PCA does not yield an accuracy of more than 50%, But the use of LDA to extract the important features significantly improves the performance of the classifier. A combination of LDA and SVM (kernel = 'rbf') is achieved to a test accuracy of 84%. Compared to holistic methods, convolutional neural networks show similar to better performance, and accuracy reaches 93.16% using MobileNetV2. Visualizing intermediate activation layers in VGG model reveals that just in deep activation layers, the color pattern and the shape of the snake contribute to the discrimination of snake species. This study presents MobileNetV2 as a powerful deep convolutional neural network algorithm for snake image classification that could be used even on mobile devices. This finding pave the road for generating mobile applications for snake image identification.

Body size miniaturization in a lineage of colubrid snakes: Implications for cranial anatomy.

As body size strongly determines the biology of an organism at all levels, it can be expected that miniaturization comes with substantial structural and functional constraints. Dwarf snakes of the genus Eirenis are derived from big, surface-dwelling ancestors, considered to be similar to those of the sister genus Dolichophis. To better understand the structural implications of miniaturization on the feeding apparatus in Eirenis, the morphology of the cranial musculoskeletal system of Dolichophis schmidti was compared with that of the miniature Eirenis punctatolineatus and E. persicus using high-resolution µCT data. The gape index was compared between D. schmidti and 14 Eirenis species. Our results show a relatively increased neurocranium size and decreased maximal jaw muscle force in E. persicus, compared with the D. schmidti, and an intermediate situation in E. punctatolineatus. A significant negative allometry in gape index relative to body size is observed across the transition from the Dolichophis to Pediophis and Eirenis subgenera. However, the gape index relative to head size showed a significant negative allometry only across the transition from the Dolichophis to Pseudocyclophis subgenus. In Dolichophis-Eirenis dwarfing lineages, different structural patterns are observed through miniaturization, indicating that overcoming the challenge of miniaturization has achieved via different adaptations.

Reptile species richness associated to ecological and historical variables in Iran.

Spatial gradients of species richness can be shaped by the interplay between historical and ecological factors. They might interact in particularly complex ways in heterogeneous mountainous landscapes with strong climatic and geological contrasts. We mapped the distribution of 171 lizard species to investigate species richness patterns for all species (171), diurnal species (101), and nocturnal species (70) separately. We related species richness with the historical (past climate change, mountain uplifting) and ecological variables (climate, topography and vegetation). We found that assemblages in the Western Zagros Mountains, north eastern and north western parts of Central Iranian Plateau have the highest number of lizard species. Among the investigated variables, annual mean temperature explained the largest variance for all species (10%) and nocturnal species (31%). For diurnal species, temperature change velocity shows strongest explained variance in observed richness pattern (26%). Together, our results reveal that areas with annual temperature of 15-20 °C, which receive 400-600 mm precipitation and experienced moderate level of climate change since the Last Glacial Maximum (LGM) have highest number of species. Documented patterns of our study provide a baseline for understanding the potential effect of ongoing climate change on lizard diversity in Iran.

A new species of Eryx (Serpentes: Erycidae) from Iran.

We describe a new species of the genus Eryx Daudin, 1803 from southern Iran that is morphologically closely related to the Indian sand boa, E. johnii. The new species, Eryx sistanensis sp. nov. has a distribution range from Zabol in the Sistan Region to the southern parts of Sistan Baluchistan, as well as Hormozgan Province of Iran. Morphologically, E. sistanensis sp. nov. differs from E. johnii by having fewer dorsal scale rows at midbody and the tail tip is not as blunt as E. johnii. The genetic distance (p-distance) between the new species and the Indian sand boa is considerable (9.1% for cytb and 11.8% for COI).

Additions to the phylogeny of colubrine snakes in Southwestern Asia, with description of a new genus and species (Serpentes: Colubridae: Colubrinae).

Reptiles are still being described worldwide at a pace of hundreds of species a year. While many discoveries are from remote tropical areas, biodiverse arid regions still harbor many novel taxa. Here, we present an updated phylogeny of colubrid snakes from the Western Palearctic by analyzing a supermatrix of all available global snake species with molecular data and report on the discovery of a new genus and species of colubrine snake from southeastern Iran. The new taxon, named Persiophis fahimii Gen. et sp. nov., is nested within a clade containing Middle Eastern and South Asian ground racers (Lytorhynchus, Rhynchocalamus, Wallaceophis, and Wallophis). This species has a derived morphology including an edentulous pterygoid and occurrence of short and blunt teeth on the palatine, maxillae and dentary bones, an elongated snout and a relatively trihedral first supralabial scale that is slightly bigger than the second, and elongated toward the tip of rostral. We also report on the osteology and phylogenetic placement of several poorly studied colubrines: Hierophis andreanus (reassigned to Dolichophis) and Muhtarophis barani.

Taxonomic status of Tropiocolotes cf. steudneri with a description of a new species of Tropiocolotes (Reptilia: Squamata: Gekkonidae) in southern Iran.

We review the status of an Iranian gecko population previously referred to Tropiocolotes cf. steudneri and describe it as a new species, Tropiocolotes hormozganensis sp. nov. We discuss the taxonomic history of this population and compare its characters with those of the other species in the genus. The new species is distinguished from other species of Tropiocolotes by possessing weakly keeled dorsal scales and smooth ventral scales, having imbricate scales on dorsal and ventral tail, possessing clearly tricarinatesubdigital scales, 48-55 dorsal scales, two pairs of postmental shields, of which the second pair is about half of the size of the first, 100-107 scales longitudinally along underside of body, 15-19 scales across head and 16-19 subdigital lamellae.