Thomas Martin

• University of Bonn

The carnassial teeth of Carnivora and Dasyuromorphia are characterized by the enlargement of the carnassial blades and reduction of crushing structures. In some species, the highly carnassialized teeth exhibit a unicuspid talonid with only the hypoconid present (“trenchant heel”). This condition is similar to that seen in the molars of pretribosphe...

We use synchrotron x-ray tomography of annual growth increments in the dental cementum of mammaliaforms (stem and crown fossil mammals) from three faunas across the Jurassic to map the origin of patterns of mamma-lian growth patterns, which are intrinsically related to mammalian endothermy. Although all fossils studied exhibited slower growth rates...

Three new lower molars of Storchodon cingulatus and a fragmentary upper molar confirm its morganucodontan affinities. Cusps b and c are relatively higher than in Morganucodon, and cusp c is larger than cusp b. Cusp a is asymmetric, with slightly distally recurved tip. All known lower Storchodon molars have a pronounced furcation between the roots o...

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...

Docodon hercynicus sp. nov. from the Upper Jurassic (upper Kimmeridgian) Süntel Formation of the Langenberg Quarry in Lower Saxony is the first docodontan recorded from Central Europe. The two lower molars available are characterised by vertical enamel ridges at the distal flank of cusp a, which are typical for Docodon. This is only the second reco...

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...

The relationship of food comminution and individual age in Tupaia belangeri is investigated. It is hypothesized that with increasing age the performance of the molar dentition decreases due to progressive tooth wear. While this relationship is well-documented for herbivores, age-related test series are largely lacking for insectivorous mammals. 15...

The Late Jurassic docodontan Haldanodon exspectatus from the Guimarota coal mine in Portugal provides important information on the evolution of the dental replacement pattern in mammaliaforms. Haldanodon shows diphyodont replacement of antemolars and non-replacement of molars. Lower incisors are replaced in alternating order with early replacement...

The present 3D Dataset contains the 3D models analyzed in Keppeler, H., Schultz, J. A., Ruf, I., & Martin, T., 2023. Cranial anatomy of Hypisodus minimus (Artiodactyla: Ruminantia) from the Oligocene Brule Formation of North America. Palaeontographica Abteilung A.

A new extinct sclerorhynchoid sawfish, Ptychotrygon ameghinorum sp. nov., is presented here based on abundant isolated teeth and some dermal denticles, which were recovered from the Mata Amarilla Formation, belonging to the lower Upper Cretaceous of the Santa Cruz Province in the Austral Basin of Patagonia, Argentina. This new species is the first...

Unambiguous morphological determination of fossil bat material is often based exclusively on mandibles, maxillae, isolated teeth, and distal epiphysis of the humerus. However, even the bony parts of the inner ear allow accurate species identification. Petrosals (i.e. bulla tympanica - temporal bone) are commonly preserved in deposits due to their d...

Carnassial teeth with slicing function evolved convergently in multiple lineages of carnivorous mammals. A 3D geometric morphometric analysis of lower carnassials of extant Carnivora, Dasyuromorphia and extinct Hyaenodonta suggests besides functional adaptation a possible phylogenetic influence on carnassial shape. The shift between lesser and high...

Due to preservation in occlusion in flattened specimens, the dentition of the proviverrine hyaenodont Lesmesodon from Messel is unadequately known, only from subadult individuals. New µCT-based studies provide now details from lingual, buccal and occlusal aspects of its dentition. This will help to gather information on the ecological niche that Le...

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...

The new spalacotheriid “symmetrodontan” Cifellitherium suderlandicum gen. et sp. nov. from the Barremian–Aptian of the Balve locality in northwestern Germany is the first record of spalacotheriids in Central Europe. The new taxon is based on one lower and two upper molars. Cifellitherium is similar to Spalacotherium, but differs by smaller styloc...

Five partially preserved mammaliaform petrosals recovered from Middle Jurassic sediments of the Berezovsk coal mine (Krasnoyarsk Krai, Russia) show similarities to other early mammaliaforms like the morganucodontan Morganucodon and the docodontan Haldanodon in having an inflated promontorium and a curved and apically inflated cochlear canal, but th...

The Upper Cretaceous (Cenomanian) Mata Amarilla Formation in western Central Santa Cruz Province of Argentina has yielded fragmentary teeth of a large ?docodontan, an australosphenidan, a meridiolestidan (Amarillodon meridionalis gen. et sp. nov.), and a stem dryolestid (Treslagosodon shehuensis gen. et sp. nov.). These represent the first possible...

The evolution of carnassial teeth in mammals, especially in the Carnivora, has been subject of many morphometric and some dental topographic studies. Here, we use a combination of dental topographic analysis (Dirichlet normal energy) and 3D geometric morphometrics of less and high carnassialized lower teeth of carnivoran, dasyuromorph and hyaenodon...

The Langenberg Quarry near Bad Harzburg has yielded the first Jurassic stem therian mammal of Germany, recovered from Kimmeridgian (Late Jurassic) near shore deposits of a palaeo-island within the Lower Saxony Basin of the European archipelago. The new stem therian is represented by one lower and three upper molars. Hercynodon germanicus gen. et sp...

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...

Multituberculata from the Lower Cretaceous (Barremian–Aptian) Balve locality in Germany are represented by two taxa, the pinheirodontid Bructerodon alatus gen. et sp. nov. and the eobaatarid Cheruscodon balvensis gen. et sp. nov. Bructerodon alatus gen. et sp. nov. is known from an upper premolar (P5) and an upper molar (M1) with a distinct distoli...

Triconodontidae are considered the first carnivorous crown mammals. A virtual reconstruction of the masticatory cycle in the Late Jurassic Priacodon showed that triconodontid dental function is characterized by precise cutting on elongated crests. The combination of traits linked to both carnivorous diets (e.g. fore-aft cutting edges) and insectivo...

Triconodon mordax , from the lowest Cretaceous (Berriasian) part of the Purbeck Group, Dorset, is known by an ontogenetic series of specimens that document aspects of tooth eruption and replacement. Based on micro‐computed tomography of four specimens we refer one mandible to a new species, Triconodon averianovi , which differs from T. mordax in ha...

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.

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...

An upper “triconodont” molar from the Late Jurassic (late Kimmeridgian) of the Langenberg Quarry in northern Germany is attributed to Storchodon cingulatus gen. et sp. nov. of Morganucodonta. The molar is characterized by continuous lingual and buccal cingula, and a relatively large, buccally-shifted cusp D which is not integrated in the buccal cin...

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...

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...

Molar crown curvature of the lower carnassials (m1) of carnivorous mammals was measured as the total Dirichlet Normal Energy (DNE) of the enamel cap. Comparatively high values occur in the mesocarnivorous morphotype, which reflects the ancestral condition for the Carnivora, with a carnassial blade besides a well-developed talonid basin. A diminutio...

A functional analysis of a well-preserved snout of the early-diverging mammaliaform Morganucodon watsoni, with matching upper and lower dentitions, and of the holotype of Megazostrodon rudnerae, showed that both taxa had a primarily orthal occlusal path. In Morganucodon, the direction was individually variable and either strictly orthal or slightly...

The Late Jurassic (late Kimmeridgian) multituberculate assemblage from the Langenberg Quarry in Northern Germany includes Paulchoffatiidae indet., the pinheirodontid Teutonodon langenbergensis, and Cimbriodon multituberculatus gen. et sp. nov. of the paulchoffatiid line. A fragmentary m1 that was formerly attributed to Eobaataridae indet. is now as...

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...

Stereoscopic microwear and 3D surface texture analyses on the cheek teeth of ten Upper Triassic to Lower Cretaceous tritylodontid (Mammaliamorpha) taxa of small/medium to large body size suggest that all were generalist feeders and none was a dietary specialist adapted to herbivory. There was no correspondence between body size and food choice. Ste...

S1 Table. Specimen details of the tritylodontid taxa analysed. Country codes refer to ISO 3166-1 alpha-2. Abbreviations: L, large-bodied; M, medium-bodied; pc, lower postcanine; PC, upper postcanine; S, small-bodied. Acronyms to museum collections: BRSUG: Geology Museum, University of Bristol, Bristol, GB; FMNH: Finnish Museum of Natural History, H...

S1 Fig. Examples of tooth morphology and wear facets in Tritylodontidae. (a) Skull of Oligokyphus sp. (MCZ 8843) in ventral view. This specimen was excluded from analysis because of postmortem alterations on the wear facets. (b) and (c) Wear facets (on high-resolution casts) of lower postcanines of Kayentatherium wellesi (MCZ 8811). In all three im...

S2 Table. ANOVA test results of tritylodontid species with N ≥ 2. Numerical parameters of stereoscopic microwear (small pits, large pits, fine scratches, and coarse scratches) and parameters of 3D surface texture (pit void volume, peak density, peak curvature, and dale area) are shown. Significant p-values are in bold.

S3 Table. PCA variances and loadings of the significant parameter variables for stereoscopic microwear and 3D surface texture. Abbreviations (as ordered in table): SP = small pits; LP = large pits; FS = fine scratches; CS = coarse scratches; Spd_rank = peak density (rank-transformed); Spc_rank = arithmetic mean peak curvature (rank-transformed); Sd...

S4 Table. Key characters of major, widely distributed, Mesozoic plant groups

Early suckler? One trait that is unique to mammals is milk suckling. Suckling requires the presence of stability and motion in the throat, both of which require a complex hyoid apparatus. Zhou et al. describe a mammaliform docodontan fossil from the Jurassic that was preserved with a nearly intact hyoid (see the Perspective by Hoffmann and Krause)....

The order Carnivora is comprised of a wide variety of taxa, which are adapted to differing amounts of meat intake (hypo-, meso- and hypercarnivores) and show a recurring pattern of convergent evolution of craniodental features, especially in molar morphology, in concurrence with their dietary adaptations. A further tendency of convergent evolution...

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...

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...

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...

Middle ear ossicles (malleus, incus, stapes) are known for few multituberculate taxa, and three different stapedial morphotypes have been suggested: (i) slender, columelliform and microperforate, (ii) robust and rod-like, and (iii) bicrural. Reinvestigation of Upper Jurassic (Kimmeridgian) mammalian petrosals from the Guimarota coal mine in central...

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,...

Dental wear facets on the occlusal surface of premolars and molars are traces of their main function, the mastication and therefore reflect masticatory movements and also paramasticatory (i.e. non-dietary use of teeth) behavior. Here we present the Modular Wear Facet Nomenclature applicable to most mammalian dentitions. Topographic positions of wea...

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...

The Langenberg Quarry near Goslar is a classic outcrop of late Oxfordian to late Kimmeridgian shallow marine strata at the northern rim of the Harz Mountains in northern Germany. Paleogeographically located in the Lower Saxony Basin, it was surrounded by paleo-islands in the Jurassic. The terrestrial fauna and flora of these islands has been invest...

The Langenberg Quarry near Goslar is a classic outcrop of late Oxfordian to late Kimmeridgian shallow marine strata at the northern rim of the Harz Mountains in northern Germany. Paleogeographically located in the Lower Saxony Basin, it was surrounded by paleo-islands in the Jurassic. The terrestrial fauna and flora of these islands has been invest...

Golden moles have zalambdodont molars with a reduced metacone in the upper and a reduced talonid in the lower molars. Generally the molar dentition of Chrysochloris asiatica is considered as representative for the molar pattern of golden moles, neglecting the morphological diversity within Chrysochloridae. The functional morphology of 15 specimens...

The molars of Eutheria are derived from the plesiomorphic tribosphenic pattern. The tribosphenic molar is characterized by a combination of shear-cutting and a crushing and grinding interaction of the upper molarprotocone and the lower molar talonid basin. The power stroke of the chewing movement is divided into two distinct phases separated by cen...

Despite its richness in Jurassic strata with a plethora of vertebrate fossils and more than 200 years of palaeontological research, no Jurassic mammals have been found in Central Europe until recently. During the 2014 fieldwork of the Europasaurus- Project, the first isolated mammal teeth were discovered at the Langenberg Quarry near Goslar in nort...

Two multituberculate molars from the Kimmeridgian of the Langenberg Quarry near Goslar (Lower Saxony, Germany) represent the first Jurassic mammals from Germany. An upper M1 with cusp formula 5L/4B is characterized by strongly ornamented enamel and is assigned to Teutonodon langenbergensis gen. et sp. n. within the plagiaulacid line. A second speci...

The Mesozoic era (252–66 million years ago), known as the domain of dinosaurs, witnessed a remarkable ecomorphological diversity of early mammals. The key mammalian characteristics originated during this period and were prerequisite for their evolutionary success after extinction of the non-avian dinosaurs 66 million years ago. Many ecomorphotypes...

The Mesozoic era (252–66 million years ago), known as the domain of dinosaurs, witnessed a remarkable ecomorphological diversity of early mammals. The key mammalian characteristics originated during this period and were prerequisite for their evolutionary success after extinction of the non-avian dinosaurs 66 million years ago. Many ecomorphotypes...

Molars of the extant lipotyphlan Solenodon show a zalambdodont crown shape that closely resembles the pretribosphenic condition of Mesozoic stem-Zatheria. In order to reconstruct the mastication cycle, abrasional and attritional wear patterns of the molars of four Solenodon paradoxus specimens were examined and the functional morphology was compare...

Middle Jurassic terrestrial vertebrate fauna of the Berezovsk coal mine in western Siberia (Russia)

Amphibetulimus krasnolutskii is known from the Middle Jurassic (Bathonian) Itat Formation of Krasnoyarsk Territory, West Siberia, Russia, by several edentulous and three dentigerous dental fragments, preserving p1, antepenultimate, and ultimate lower molars, and by an upper molar. It is unique among stem therians by widely open trigonids on the pos...

The Middle and early Late Jurassic Qigu and Shishugou Formations of the southern and central Junggar Basin yielded teeth of theropods (Theropoda indet.), sauropods (Eusauropoda indet.), and stegosaurs. The dinosaur assemblage of the southern Junggar Basin is less diverse and is represented by smaller forms than in the central part of the basin. The...

Mammals from the Middle Jurassic of Western Siberia

The South American ungulate Pyrotherium romeroi provides a new enamel type, “Pyrotherium-enamel”. It is characterized by vertically oriented bands that differ from vertical Hunter–Schreger-bands in being wider and having a specific internal feather-like structure. The enamel is formed exclusively by prisms with keyhole-shaped cross sections. This p...

ABSTRACT—Anthracolestes sergeii, gen. et sp. nov., based on three isolated lower molars and several edentulous dentary fragments from the Middle Jurassic (Bathonian) Itat Formation at Berezovsk Quarry in Krasnoyarsk Territory, Russia, is the oldest and most basal representative of Dryolestidae. It shows four unambiguous synapomorphies of Dryolestid...

The Liuhuanggou locality within the Late Jurassic (Oxfordian) Qigu Formation in the southern Junggar Basin has produced a rich microvertebrate assemblage. The bonebed has yielded a large amount of bones and teeth of aquatic and terrestrial vertebrates, such as hybodontid sharks, actinopterygians, temnospondyles, lissamphibians, xinjiangchelyid turt...

In the Central Asian Turpan Basin, large areas of Mesozoic sediments are exposed which had seen very limited paleontological interest for a long time. Fieldwork conducted by the Sino-German Paleontological Cooperation Project in Middle to Late Jurassic fluvial and lacustrine sediments near the county of Shanshan (Xinjiang, NW China) has now vastly...

The earliest evolution of mammals and origins of mammalian features can be traced to the mammaliaforms of the Triassic and Jurassic periods that are extinct relatives to living mammals. Here we describe a new fossil from the Middle Jurassic that has a mandibular middle ear, a gradational transition of thoracolumbar vertebrae and primitive ankle fea...

The endemic South American mammals Meridiolestida, considered previously as dryolestoid cladotherians, are found to be non-cladotherian trechnotherians related to spalacotheriid symmetrodontans based on a parsimony analysis of 137 morphological characters among 44 taxa. Spalacotheriidae is the sister taxon to Meridiolestida, and the latter clade is...

The docodont Haldanodon exspectatus, a mammaliaform from the Late Jurassic of Portugal, is a crucial taxon for studying higher-level relationships of mammaliaforms and their morphological evolution. Based on high-resolution computed tomography scanning of three specimens of Haldanodon, we developed a new reconstruction of the basicranium including...

Dryolestes leiriensis is a Late Jurassic fossil mammal of the dryolestoid superfamily in the cladotherian clade that includes the extant marsupials and placentals. We used high resolution micro-computed tomography (µCT) scanning and digital reconstruction of the virtual endocast of the inner ear to show that its cochlear canal is coiled through 270...

The semicircular canals (SCs), part of the vestibular apparatus of the inner ear, are directly involved in the detection of angular motion of the head for maintaining balance, and exhibit adaptive patterns for locomotor behaviour. Consequently, they are generally believed to show low levels of intraspecific morphological variation, but few studies...

The long-term isolation of South America during most of the Cenozoic produced a highly peculiar terrestrial vertebrate biota, with a wide array of mammal groups, among which caviomorph rodents and platyrrhine primates are Mid-Cenozoic immigrants. In the absence of indisputable pre-Oligocene South American rodents or primates, the mode, timing and b...

Pretribosphenic dryolestoid molars are characterized by a reversed triangular alignment of the "primary trigon" (formed by the paracone, metacone and stylocone) and trigonid crucial for the embrasure shearing process. These molars are abraded along the protocristid and paracristid, and show a typical wear pattern with mesially and distally sloping...

The fossil South American ungulates are of great interest relative to the new phylogenetic framework elaborated for living placental mammals. In particular, studies on these endemic taxa can allow for testing congruence between southern placental phylogeny and plate tectonics, beyond what has already been suggested in the Atlantogenata hypothesis b...

Dental measurements, length (L), width (W), crown height (H), and crown height index ratio (H/L), of Steneofiber siamensis n. sp. teeth

Die detaillierte Analyse von komplexen anatomischen Strukturen ist ein Schlussel zum Verstandnis der Evolution. In der Palaontologie (Lehre von den Fossilien) werden vor allem die fossil erhaltungsfahigen Hartteile, Knochen und Zahne von viele Millionen Jahre alten Organismen untersucht. Die Mikro-Computertomografie (Mikro-CT) hat die palaontologis...