Pavel P. Skutschas

• PhD
• Saint Petersburg State University at St Petersburg University

The allosauroid theropod dinosaurs of the clade Carcharodontosauridae were the apex predators in terrestrial ecosystems of the Early Cretaceous but were replaced in this ecological niche by Tyrannnosauridae in the Late Cretaceous. Details of this turnover are poorly known because only two transitional ecosystems, containing both carcharodontosaurid...

Neurocranial features appear to be phylogenetically informative and key in assessing the still contentious relationships within Crocodylomorpha. However, the braincases of many non-crocodylian taxa are incompletely studied precluding the assessment of evolutionary modifications at the base of Crocodylia. Here, we describe the braincase osteology an...

The presence of pedicellate (subpedicellate) teeth with two calcification centers and a weakly mineralized dividing zone is described for archaic stem salamanders (Middle Jurassic-Early Cretaceous representatives of Karauridae). The presence of subpedicellate teeth, typical of the late larval stage of modern salamanders, confirms the neotenic natur...

This paper describes the morphology and histological structure of the femora of salamanders of the genus Kiyatriton K. krasnolutskii from the Middle Jurassic (Bathonian) Berezovsk Quarry locality in Krasnoyarsk krai and K. leshchinskiyi from the Lower Cretaceous (Aptian) Shestakovo 1 locality in the Kemerovo Region. The femora of Kiyatriton are cha...

We provide a detailed redescription of all available material for the geologically oldest proteid salamander Bishara backa from the Upper Cretaceous (Santonian – lower Campanian) Bostobe Formation in Kazakhstan, consisting an atlantal centrum (neotype of Bishara backa) and a trunk vertebra. Bishara backa is characterised by the following combinatio...

The noasaurid ceratosaur Kiyacursor longipes gen. et sp. nov. is described based on a fragmentary skeleton including cervical vertebra, pectoral girdle, humerus and hind limbs from the Lower Cretaceous (Aptian) Ilek Formation at Shestakovo 1 locality in Western Siberia, Russia. This is the first ceratosaur from the Early Cretaceous of Asia, extendi...

The morphology and histological structure of the humerus and femora of the stem karaurid salamander Kulgeriherpeton ultimum Skutschas et al., 2018, from the Lower Cretaceous Teete locality, Republic of Sakha (Yakutia) is described. The microanatomical and histological structure of K. ultimum is characterized by the presence of a thick compact prima...

Docodonta are the most abundant and taxonomically diverse group of mammaliaforms in the high paleolatitude Lower Cretaceous Teete locality in Yakutia, Russia. Docodontans are represented by the tegotheriids Khorotherium yakutense and Ergetiis ichchi gen. et sp. nov., and possibly two more taxa known from fragmentary specimens (Docodonta indet.). Er...

Disarticulated cranial and postcranial bones of a giant salamander (Cryptobranchidae: Andrias sp.) were found in the Upper Pliocene deposits of the Belorechensk locality in the Northern Caucasus. These remains probably belonged to one individual that died during a stage of rapid growth and had a total length of about 90-100 cm. The giant salamander...

A few localities world wide are known to have remainsof dinosaurs andothervertebrate animalsthat livedin thepolarlatitude region during the Mesozoic era. The Teete locality in the Vilyui River Basin, Yakutia (Russia) is one of the few known dinosaur localities in the Northern Hemisphere. In 1988, 2002–2012 school children participated in asearch fo...

A fragmentary tibia of an actively growing sub-adult individual from the Upper Cretaceous (Maastrichtian) Udurchukan Formation at Kundur, Amur oblast, Far East, Russia, is similar to the tibia of Qiupalong henanensis from the Maastrichtian of Henan Province, China, in bearing a weak posteromedial ridge at the distal end and equally projecting dista...

A new karaurid stem salamander, Kuzbassia sola gen. et sp. nov., from the Lower Cretaceous (Aptian) Ilek Formation of Shestakovo 1 locality in Western Siberia, Russia, is described on the basis of isolated vertebrae, including incomplete atlantal and trunk vertebral centra. The new taxon is diagnosed by the following unique combination of vertebral...

KOKM A, the associated caudal vertebrae of a sauropod from the Lower Cretaceous (Aptian) Ilek Formation at Shestakovo 3 locality in Kemerovo–Kuzbass oblast, Western Siberia, Russia, shows a unique combination of derived caudal vertebrae and plesiomorphic and highly diverse haemal arches (chevrons). The anterior, middle, and posterior caudal vertebr...

According to the degree of development of the main cusps and the presence of a small lingual part, the upper molar of a docodontan from the Bol’shoi Kemchug 4 locality (Ilek Formation, Lower Cretaceous) in the Krasnoyarsk Territory corresponds to M1 of Agilodocodon scansorius Meng et al., 2015 from the Middle Jurassic of China. The described tooth...

Eutriconodonta are an important group of early crown mammals with a wide distribution in the Jurassic-Cretaceous of the Northern Hemisphere and few occurrences in the Southern Hemisphere. Three taxa of eutriconodontans are known from the Early Cretaceous high-latitude Teete vertebrate assemblage in Yakutia, Russia: Sangarotherium aquilonium (Eutric...

According to the degree of development of the main cusps and the presence of a small lingual part, the upper molar of a docodontan from the Bol’shoi Kemchug 4 locality (Ilek Formation, Lower Cretaceous) in the Krasnoyarsk Territory corresponds to M1 of Agilodocodon scansorius Meng et al., 2015 from the Middle Jurassic of China. The described tooth...

The ontogenetic status of the known specimens of alvarezsaurid theropod dinosaurs is revised. We present histological data that the holotype of Parvicursor remotus from the Upper Cretaceous Barungoyot Formation of Mongolia is not an adult individual, as previously thought, but a juvenile less than one year old. The miniaturization took place only i...

A new species of Dunkleosteus, D. tuderensis sp. nov., is named based on an infragnathal from the Famennian of the Tver Region, Russia. CT scanning of the holotype revealed two high-density bony constituents comparable in position and interrelations to components described for coccosteomorph arthrodires, supported by the presence of at least two cl...

Crown salamanders first appeared in the Middle Jurassic (Bathonian) and remains of these oldest representatives of the group have been found in various vertebrate localities in China, Western Siberia, and Western Europe. Here, we report the discovery of an indeterminate crown salamander in the Middle Jurassic (Bathonian) Peski locality of Moskvoret...

Here we determine the individual age of a basal mosasaur (subfamily Halisaurinae) using zyga-pophyseal skeletochronology. This study is based on the cervical vertebra from the Late Cretaceous Beloe Ozero locality (Saratov Region). By of counting the zygapophyseal growth rings on the right prezygapophy-sis, it has been revealed that the age of the a...

Salamanders are an important group of living amphibians and model organisms for understanding locomotion, development, regeneration, feeding, and toxicity in tetrapods. However, their origin and early radiation remain poorly understood, with early fossil stem-salamanders so far represented by larval or incompletely known taxa. This poor record also...

The revised dinosaur assemblage from the Lower Cretaceous Murtoi Formation at Mogoito locality in Transbaikalia, Russia, includes lithostrotian titanosaur Tengrisaurus starkovi known from caudal vertebrae, Sauropoda indet. represented by isolated teeth and metatarsal IV, theropods Ornithomimosauria, Therizinosauria, Dromaeosauridae, Theropoda indet...

Для определения индивидуального возраста базального мозазаврида (представителя подсемейства Halisaurinae) из позднемелового местонахождения Белое Озеро (Саратовская область) по шейному позвонку был использован метод зигапофизной скелетохронологии. В результате подсчета зигапофизных ростовых гребней на правом переднем сочленовном отростке было устан...

A mammalian petrosal from the Lower Cretaceous Teete locality in Yakutia (Russia) shows a prominent and complex system of venous channels in the bony wall of the pars cochlearis surrounding the straight cochlear canal. This complex venous system is distinctive and more strongly developed than in other mammalian petrosals. A bony ridge is present on...

A distal fragment of the wing metacarpal from the Lower Cretaceous Ilek Formation at the Novochernorechensk locality in Krasnoyarsk Territory, West Siberia, Russia, is nearly identical to the wing metacarpal of the dsungaripterid pterosaur Lonchognathosaurus acutirostris from the Lower Cretaceous of North-West China. It is identified here as cf. Lo...

The early ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of Western Siberia, Russia, is one of the most advanced and largest (up to 2.5 m) members of the genus. Here we present a description of ontogenetic changes in the long-bone histology of this species. Analysis of a growth series of femora demonstrates significant hist...

A fragmentary diapsid left maxilla from the Bathonian Peski locality in Moscow Region, previously referred to Choristodera, is identified as Lepidosauromorpha indet. This specimen represents the first fossil record of basal lepidosauromorphs in the Middle Jurassic of European Russia. Among basal lepidosauromorphs, the maxilla from the Peski localit...

Present‐day crocodylians exhibit a remarkably akinetic skull with a highly modified braincase. We present a comprehensive description of the neurocranial osteology of extant crocodylians, with notes on the development of individual skeletal elements and a discussion of the terminology used for this project. The quadrate is rigidly fixed by multiple...

This paper describes the microanatomical and histological structure of different-sized femora and hypocentra of the archegosauroid amphibian Platyoposaurus stuckenbergi from the Middle Permian (Urzhum horizon, Estemmenosuchus uralensis zone) of Eastern Europe. Age variability is discussed in a comparative context, along with the ecology of the spec...

Isolated stegosaurian teeth from the Early Cretaceous high-latitude (palaeolatitude estimate of N 62°- 66.5°) Teete locality in Yakutia (Eastern Siberia, Russia) are characterized by a labiolingually compressed, slightly asymmetrical and mesiodistally denticulated (9–14 denticles) crown, a pronounced ring-like cingulum, as well as a “complex networ...

Albanerpetontids are an extinct clade of salamander-like lissamphibians characterised by features such as fused frontals and sculptured skull roof bones. Here we provide a histological analysis of the fused and sculptured frontals in two Late Cretaceous species of the type genus Albanerpeton sensu lato that differ in body size: moderate-sized ‘Al.’...

An additional anterior caudal vertebra of a titanosaurian sauropod Tengrisaurus starkovi from the Lower Cretaceous (Barremian–Aptian) Murtoi Formation of Transbaikalia, Asiatic Russia, reveals new morphological details of this taxon. The new characters include dorsoventrally compressed cotyle and condyle of the centrum and a prominent ridge separat...

Six dinosaurian taxa, Therizinosauridae indet., Ornithomimosauria indet., Dromaeosauridae indet., Titanosauridae indet., cf. Mongolosaurus sp., and Psittacosaurus sp., are identified and described from late Barremian to middle Aptian strata of the Murtoi Formation at the Mogoito locality in Buryatia, western Transbaikalia, Russia. The Mogoito verte...

This study describes the microanatomical and histological structure of the femur and hypocentra of the neotenic temnospondyl amphibian Dvinosaurus campbelli from the Late Permian locality Gorok-hovets, Vladimir Region (Upper Vyatkian Substage, subzone Chroniosuchus paradoxus of the Scutosaurus karpinskii zone). The femur of D. campbelli is characte...

The first finding of the docodontan (a lower molar of Sibirotherium sp.) from the Bol'shoi Kemchug 3 locality (Ilek Formation, Lower Cretaceous) in Krasnoyarsk Territory is described. Sibirotherium rossicum, one of the youngest docodontans in the geological record, is known from the Ilek Formation of the Shestakovo 1 locality (Kemerovo Region). Pre...

A new salamandroid salamander, Balveherpeton hoennetalensis gen. et sp. nov., from the Lower Cretaceous (Barremian– Aptian) Balve locality in the Sauerland, Germany, is described on the basis of fragmentary atlases, trunk and caudal vertebrae. Balveherpeton hoennetalensis gen. et sp. nov. is characterized by the following combination of vertebral c...

We describe a new euharamiyidan taxon Cryoharamiya tarda, gen. et sp. nov. from the Lower Cretaceous of Yakutia, East Siberia, Russia. The Early Cretaceous Cryoharamiya is the youngest representative of Euharamiyida in the fossil record. This new taxon extends significantly the stratigraphic and geographic ranges for Euharamiyida.

We describe in detail three braincases of the ankylosaur Bissektipelta archibaldi from the Late Cretaceous (Turonian) of Uzbekistan with the aid of computed tomography, segmentation, and 3D modeling. Bissektipelta archibaldi is confirmed as a valid taxon and attributed to Ankylosaurinae based on the results of a phylogenetic analysis. The topograph...

Tashtykia primaeva gen. et sp. nov. and Tagaria antiqua gen. et sp. nov. (Multituberculata incertae sedis) are described based on isolated teeth from the Middle Jurassic (Bathonian) Itat Formation from the Berezovsk coal mine in Krasnoyarsk Territory, Western Siberia, Russia. Tashtykia primaeva gen. et sp. nov. is characterized by a P5 with three r...

Salamanders (Caudata) are one of the three modern groups of amphibians known from the Middle Jurassic. The early stages of evolution of these amphibians are still poorly known, especially for stem taxa of Jurassic age. A new small-sized stem salamander, Egoria malashichevi gen. et sp. nov., from the Middle Jurassic (Bathonian) Itat Formation of the...

Isolated sauropod teeth from the Early Cretaceous Teete locality in Yakutia (Eastern Siberia, Russia) are the only evidence that sauropods lived in high latitudes (palaeolatitude estimate of N 62°) in the Northern Hemisphere. The spatulate broad tooth crowns of adult individuals lack marginal denticles while these are present in a juvenile tooth. T...

Three new euharamiyidan taxa are described based on isolated teeth from the Middle Jurassic (Bathonian) Itat Formation of the Berezovsk coal mine in Krasnoyarsk Territory, Western Siberia, Russia. The newly erected Sharypovoia, gen. nov., is referred to the Shenshouidae based on a premolariform p4, in which the main cusp and basined heel are surrou...

Three sauropod middle caudal vertebrae are described from the three different localities within the Lower Cretaceous (Barremian-Aptian) Ilek Formation in Krasnoyarsk Territory, Western Siberia, Russia. All vertebrae are strongly procoelous and can be referred to Lithostrotia indet. LMCCE 005/40 from Bol'shoi Kemchug 3 locality has a ventral groove...

New postcranial bones (cervical and caudal vertebrae, chevron, fibula) of the proceratosaurid tyrannosauroid Kileskus aristotocus from the Middle Jurassic (Bathonian) Itat Formation at Berezovsk coal mine, Krasnoyarsk Territory, Western Siberia, Russia, reveal three possible autapomorphies of Kileskus: a deep anterior recess between the neural cana...

This paper describes fragmentary turtle material (isolated basisphenoid, shell bones, humerus and ilium) from the Lower Cretaceous (Berriasian–Barremian) Teete locality in Yakutia (Eastern Siberia, Russia). All the material is attributed to one taxon of basal turtles (Mesochelydia indet.), based on the morphology of the basisphenoid, shell bones an...

Pareiasaurs were one of the main clades of large herbivorous tetrapods in Middle–Late Permian continental ecosystems. Despite abundant pareiasaur material, many aspects of their biology remain poorly known. This paper provides a description of ontogenetic changes in long-bone and rib microanatomy/histology of two Upper Permian pareiasaurs from Russ...

A sample of 136 isolated theropod teeth from nine vertebrate localities within the Lower Cretaceous (Barremian-Aptian) Ilek Formation in West Siberia, Russia, can be separated into five dental morphotypes referred to five or six theropod taxa based on morphological characters. The Morphotype A includes small to large lateral teeth with relatively l...

This paper presents histological data on the long bones of different size (age) individuals of the basal cryptobranchid salamander Eoscapherpeton asiaticum from the Upper Cretaceous(Turonian) of Uzbekistan. E. asiaticum is similar to modern members of Cryptobranchidaein being relatively large (estimated body length up to 50–60 cm), aquatic, and neo...

Isolated sauropod teeth and caudal vertebrae from the Middle Jurassic Itat Formation of the Berezovsk coal mine, Krasnoyarsk Territory, Russia, are attributed to the endemic Asiatic eusauropod family Mamenchisauridae based mostly on phenetic similarity. The few large anterior teeth lack marginal denticles. In small, possible juvenile posterior teet...

Early stages in the evolution of salamanders

Here we describe life history traits in the giant cryptobranchid salamander Aviturus exsecratus from the Paleocene of Mongolia using non-destructive approach for skeletochronological analysis based on the counting of cyclical growth rings on articular surfaces of zygapophyseal processes of vertebrae (= zygapophyseal skeletochronology). We found tha...

A new stem salamander, Kulgeriherpeton ultimum gen. et sp. nov., is described based on a nearly complete atlas (holotype) from the Lower Cretaceous (Berriasian–Barremian) Teete vertebrate locality in southwestern Yakutia (Eastern Siberia, Russia). The new taxon is diagnosed by the following unique combination of atlantal characters: the presence of...

Remains of neosuchian crocodyliforms (isolated teeth, fragment mandibular bone) from the Middle Jurassic (Bathonian) Peski locality in the Moscow Region are described for the first time. The neosuchian from Peski is characterized by well-pronounced ornamentation on the dermal skull bones, and also bicarinate teeth oval in cross section without serr...

The Early Cretaceous (?Berriasian-Barremian) Teete vertebrate locality in Western Yakutia, East Siberia, Russia, has produced mammal remains that are attributed to three taxa: Eleutherodontidae indet. cf. Sineleutherus sp. (Haramiyida; an upper molariform tooth), Khorotherium yakutensis gen. et sp. nov. (Tegotheriidae, Docodonta; maxillary fragment...

In the present paper, we provide a comprehensive revision of the large-sized neosuchians Kansajsuchus and ‘Turanosuchus’ from the Late Cretaceous of Central Asia. Kansajsuchus extensus from the Kansai locality of the Yalovach Formation, Tadzhikistan, is confirmed as a valid taxon. Previously hypothesized goniopholidid affinities of Kansajsuchus are...

Morphology and histology of several fragmentary turtle specimens from the Middle Jurassic locality in the Berezovsk quarry (Krasnoyarsk Region, Russia) are described, including Testudines indet. 1 (costal VIII), Testudines indet. 2 (two ornamented shell fragments), and Testudines indet. 3 (distal part of a humerus), and also skeletal elements of An...

Osseous anomalies/pathologies in the Late Cretaceous cryptobranchid salamander Eoscapherpeton asiaticum from the Turonian Bissekty Formation of Uzbekistan are analyzed using gross morphological description, microCT, and histologic analysis. These pathologies result from trauma (fractured and subsequently healed dentary and femora; hematoma on femur...

Developmental changes in salamander skulls, before and after metamorphosis, affect the feeding capabilities of these animals. How changes in cranial morphology and tissue properties affect the function of the skull are key to decipher the early evolutionary history of the crown-group of salamanders. Here, 3D cranial biomechanics of the adult Salama...

Sibirotitan astrosacralis nov. gen., nov. sp., is described based on isolated but possibly associated cervical and dorsal vertebrae, sacrum, and previously published pedal elements from the Lower Cretaceous (Barremian?) Ilek Formation at Shestakovo 1 locality (Kemerovo Province, Western Siberia, Russia). Some isolated sauropod teeth from the Shesta...

The Lower Cretaceous Ilek Formation in Western Siberia (Russia) has yielded various vertebrate fossils, including skeletal remains of dinosaurs. Here we report on a fragmentary theropod egg from the vertebrate locality Shestakovo 3 of the Ilek Formation in Kemerovo Province. We assign the specimen to the oogenus Prismatoolithus (oofamily Prismatool...

Upper and lower tritylodontid postcanine teeth from the Middle Jurassic (Bathonian) Itat Formation of the Berezovsk coal mine, Krasnoyarsk Territory, Russia, are referred to Stereognathus sp. The genus Stereognathus Charlesworth, 1855 (Polistodon He and Cai, 1984, Xenocretosuchus Tatarinov and Mashenko, 1999, and Montirictus Matsuoka et al., 2016,...

This paper presents histological data on the shell bones of different size (age) individuals of the basal pan-carettochelyid Kizylkumemys schultzi from the Upper Cretaceous (Cenomanian) of Usbekistan. Ontogenetic changes in the shell bone histology of Kizylkumemys schultzi correspond to those characteristic of other turtles. Comparison of the shell...

Tengrisaurus starkovi, gen. et sp. nov., is described based on three caudal vertebrae from the Lower Cretaceous (Barremian?) Murtoi Formation at Mogoito locality, near Gusinoe Lake in Buryatia, Russia. The new taxon is characterized by strongly procoelous anterior and middle caudal vertebrae, with strongly developed pre-epipophyses, highly pneumati...

There are ten known Lower Cretaceous localities for skeletal remains of choristoderes in Siberia (Russia). Choristoderan remains at all these localities are represented by isolated bones, usually by isolated vertebrae of Choristodera indet. Three choristoderan taxa in two geological units were identified: the non-neochoristodere Khurendukhosaurus s...

Baidabatyr clivosus, gen. et sp. nov. (Multituberculata incertae sedis), is described on the basis of an ultimate upper premolar (P5) from the Lower Cretaceous Ilek Formation at Bol'shoi Kemchug 3 locality in Krasnoyarsk Territory, Russia. The new taxon differs from all known multituberculates by the cusp formula of the ultimate upper premolar (4:5...

The Berezovsk coal mine in western Siberia has yielded the most diverse Middle Jurassic limnic and terrestrial vertebrate assemblage of Asia. The vertebrate remains were recovered by screen washing from floodplain deposits on top of a mighty coal seam of the Bathonian Itat Formation. A total of 29 vertebrate taxa has been recorded so far, including...

An ornithomimid theropod dinosaur from the Upper Cretaceous (Turonian) Bissekty Formation of Uzbekistan is one of the basal members of Ornithomimidae. Here we present a description of ontogenetic changes in the long-bone histology of this taxon and distinguish four distinct histological stages. Analysis of a growth series of femora demonstrates ear...

Late Cretaceous vertebrates are known from the Turonian Zhirkindek and Santonian Bostobe formations in the western Kazakhstan region northeast of the Aral Sea. The Zhirkindek vertebrate assemblage resembles that known from the Turonian Bissekty Formation of the Kyzylkum Desert, Uzbekistan, because of the presence of the rhinobatoid ray Myledaphus t...

Maofelis cantonensis gen. and sp. nov. is described based on a complete cranium from the middleupper Eocene Youganwo Formation of Maoming Basin, Guangdong Province, China. The new taxon has characters diagnostic for Nimravidae such as a short cat-like skull, short palate, ventral surface of petrosal dorsal to that of basioccipital, serrations on th...

Kokartus honorarius from the Middle Jurassic (Bathonian) of Kyrgyzstan is one of the oldest and basalmost salamanders in the fossil record, and this taxon is useful for documenting a primitive caudate condition and patterns of character state transformations within Caudata. Here, we provide a histological analysis of its dermal bones based on two t...

The early evolution of salamanders, which are one of the three living groups of lissamphibians, is not well known. Both stem- and crown-group salamanders first appeared in the Middle Jurassic (Bathonian), but subsequently had different evolutionary histories: stem salamanders were thought to have gone extinct in the Late Jurassic, while crown salam...