Close Affinity Research Articles

In for a penny, in for a pound: The trouble with offshore balancing and why it matters that “1917” was not “1941”

Over the past couple of decades, students of American grand strategy have debated the merits (or lack thereof) of an orientation toward the global balance of power that has come to be known as “offshore balancing.” Its critics hold offshore balancing simply to be another way of expressing the dangerous allure of strategic “restraint,” or even “isolationism.” Its enthusiasts, by contrast, see in it nothing other than the best conceivable grand strategy for America, enabling Washington to avoid the pitfalls of either too little or too much interventionism in global affairs. This article challenges both positions, and argues that the historical record of offshore balancing as an American strategic orientation leads to the conclusion that, far from being a crypto-isolationist grand strategy, it actually betrays close affinities with the so-called “maximalism” to which its champions believe it to be superior.

Geology and mineral assemblages of the early Cambrian black shales in the South Qinling: Implications for vanadium and barium mineralization

Early Cambrian black shales in the South Qinling (SQL) of China constitute one of the world's most important vanadium- and barium-metallogenic belts. It is controversial on the enrichment mechanics of vanadium (V) and barium (Ba) mineralization. The V and Ba mineralization in the Xichuan area from the northern SQL is mainly hosted by shales and chert of the early Cambrian black shales. We conducted mineralogy and geochemistry studies to reveal the mineralization process. Electron probe X-ray microanalysis (EPMA) studies show V is enriched in jarosite, illite and chlorite in shales. The jarosite develops as concretions or flakes and shows close affinity with apatite, with biogenic structures. EPMA and X-ray maps indicate a V heterogenetic distribution within illite and chlorite. Barite occurs as spots and veins in the dark chert and siliceous shale. K-feldspar in shales occurs as columns and flakes with inhomogeneous Ba concentrations. Calcite is intergrown with quartz and Ba-enriched K-feldspar closely in the shales recording the fluctuation of pH values in the diagenetic stage. An acidity environment favors silicification, and increased pH leads to silica dissolution and calcification along with illitization and chloritization. Slightly enriched heavy rare earth elements, positive Eu anomalies, and fluorite from the shales and chert suggest the hydrothermal fluid has existed. Compared with the representative V and Ba deposits associated with black shales worldwide, these deposits occurred synchronously with extinction or anoxic events as both V and Ba mineralization are redox-dependent and associated with organisms. These events could lead to the initial enrichment of V and Ba. Our study suggests that V and Ba mineralization is mainly associated with pH fluctuation in the diagenetic and biogenic processes.

The systematic affinities between the Lower Cretaceous Ammonoidea Protacanthoplites abichi (Anthula, 1900) and Acanthohoplites aschiltaensis (Anthula, 1900)

This work provides the first revision and illustration of the type material of the ammonite species Parahoplites abichi Anthula [Type species of Protacanthoplites Tovbina] and Parahoplites aschiltaensis Anthula [Type species of Acanthohoplites Sinzow] from the upper Aptian (Lower Cretaceous) of Dagestan, Russia. The close affinities and synonymy between these two species are confirmed, and Acanthohoplites aschiltaensis is here retained as the senior valid name by its long quoting history and its historical use as a zonal index of the upper Aptian. The genus Protacanthoplites should be thus synonymised with Acanthohoplites by priority in the date of publication. Comparison with, and distinction from, closely allied Acanthohoplitidae is provided.

Development of a back-arc basin from initial rifting to seafloor spreading: Constraints from Paleozoic basic rocks in the North Qinling accretionary orogen, central China

The progression from initial back-arc rifting to back-arc opening in ancient orogenic collages is important for reconstructing subduction histories, constraining tectonic switching, and understanding crustal growth and evolution. However, it is difficult to constrain this transition in ancient arcs. The Qinling-Dabie orogenic belt is one of the most important orogenic belts in eastern Asia, yet the history of Paleozoic accretionary processes in this belt remains equivocal, owing to a poor understanding of back-arc opening processes in the Erlangping unit. In this study, we present whole-rock geochemical analyses of mafic dikes in the Erlangping unit, along with U-Pb ages and Hf-O isotope compositions of zircon from these dikes. Zircon secondary ion mass spectrometry (SIMS) dating of these mafic dikes yielded U-Pb ages of 453 ± 3 Ma. The mafic dikes are calc-alkaline and are characterized by high K2O contents (1.16−3.16 wt%). They have enriched ([La/Yb]N = 4.3−14.9) light rare earth elements (REEs) and relatively flat heavy REE ([Dy/Yb]N = 0.9−1.5) patterns, and they exhibit enrichment in large ion lithophile elements (LILEs) but depletion in high field strength elements (HFSEs), resembling arc-like magmatism. These mafic dikes are characterized by relatively enriched initial 87Sr/86Sr (0.7049−0.7059), chondritic to slightly radiogenic εNd(t) (−0.36 to 1.33), and radiogenic whole-rock and zircon εHf(t) (+7.2−7.6 and +7.5−7.8, respectively). The zircons have δ18O values (5.0‰ ± 0.1‰) similar to those of normal mantle zircon. Accordingly, we interpret that the mafic dikes were derived from an enriched lithospheric mantle source metasomatized by subducted Proto-Tethys (Shangdan) ocean material. In contrast, previously reported ca. 440 Ma gabbros from the Erlangping unit are tholeiitic and have lower incompatible trace-element concentrations with less enrichment in LILEs and less depletion in HFSEs than the mafic dikes presented here. Whole-rock Nd and zircon Hf isotopic compositions suggest that these Silurian gabbros were derived from partial melting of a more depleted mantle with the involvement of asthenosphere, and they have a close geochemical affinity with back-arc basin basalts. In addition, trace-element ratios and geochemical modeling suggest higher melting pressures for the mafic dikes than the gabbros. The geochemical differences show systematic variations from island-arc basalt into back-arc basin basalt types, which is consistent with the magma source evolution of the Mariana Trough. Thus, we interpret that the ca. 454 Ma mafic dikes were emplaced when the infant arc split, and they record initial back-arc rifting in the Erlangping unit, whereas the Silurian gabbros subsequently formed during the opening of the back-arc basin. Our study provides a paradigm for deciphering the evolution of back-arc basins through the study of spatiotemporal geological and geochemical variations of mafic intrusions in ancient accretionary orogens.

Chloroplast genome evolution and phylogeny of the early-diverging charophycean green algae with a focus on the Klebsormidiophyceae and Streptofilum.

The Klebsormidiophyceae are a class of green microalgae observedglobally in both freshwater and terrestrial habitats. Morphology-based classification schemes of this class have been shown to be inadequate due to the simple morphology of these algae, the tendency of morphology to vary in culture versus field conditions, and rampant morphological homoplasy. Molecular studies revealing cryptic diversity have renewed interest in this group. We sequenced the complete chloroplast genomes of a broad series of taxa spanning the known taxonomic breadth of this class. We also sequenced the chloroplast genomes of three strains of Streptofilum, a recently discovered green algal lineage with close affinity to the Klebsormidiophyceae. Our results affirm the previously hypothesized polyphyly of the genus Klebsormidium as well as the polyphyly of the nominal species in this genus, K. flaccidum. Furthermore, plastome sequences strongly support the status of Streptofilum as a distinct, early-diverging lineage of charophytic algae sister to a clade comprising Klebsormidiophyceae plus Phragmoplastophyta. We also uncovered major structural alterations in the chloroplast genomes of species in Klebsormidium that have broad implications regarding the underlying mechanisms of chloroplast genome evolution.

Insights into the habitat associations, phylogeny, and diet of Pipistrellus maderensis in Porto Santo, northeastern Macaronesia

Abstract. Around 60 % of all bat species occur in islands, and nearly one in four is an insular endemic. Bats are often the only native terrestrial mammals in oceanic islands, and despite increasing anthropogenic pressures, little is known about the distribution, natural history, and population status of most insular bat populations. The sub-tropical archipelago of Madeira is composed of the volcanic islands of Madeira, Porto Santo, and Desertas and is home to the Macaronesian endemic Pipistrellus maderensis, to the endemic subspecies Nyctalus leisleri verrucosus, and to Plecotus austriacus. Pipistrellus maderensis is known to both Madeira and Porto Santo, whereas the other two species have only been recorded in the former. However, no bats have been recorded in Porto Santo for over 15 years, raising fears that bats are probably extinct in the island. In July 2021, we conducted an island-wide acoustic survey using AudioMoth passive acoustic recorders, leading to the detection of Pipistrellus maderensis in 28 out of the 46 sampling sites (60 %). The species' activity was strongly associated with artificial water sources, and genetic samples from six captured individuals revealed that the populations of Pipistrellus maderensis in Porto Santo and Madeira have a close phylogenetic affinity. Furthermore, using DNA metabarcoding, we found that the species feeds on a wide variety of insects, including several economically important pest species and disease vectors. These findings emphasise the need to target more conservation and research efforts towards extant island bat populations and the potential ecosystem services they provide.

The First Instrumentally Documented Fall of an Iron Meteorite: Orbit and Possible Origin

A bright fireball observed on 2020 November 7, over Scandinavia, produced the first iron meteorite with a well-determined pre-atmospheric trajectory. We calculated the orbit of this meteoroid and found that it demonstrates no close affinity with the orbit of any known asteroid. We found that the meteoroid (or its parent body) most probably entered the near-Earth orbit from the main asteroid belt via either ν 6 secular resonance with Saturn (89%) or 3:1 mean-motion resonance with Jupiter (11%). The long YORP timescale of the meteoroid suggests that it could have been produced in the main asteroid belt and survived the journey to the near-Earth orbit.

Autism and Post-Human: A Cyborgian Reading of Sabina Berman’s Me Who Dove into the Heart of the World

ABSTRACT The concept of “cyborg” in Donna Haraway’s much-discussed “A Cyborg Manifesto” (1985) is outstanding in its depiction of the hybrid body that is untouched by long-standing polar dichotomy stemming from a hierarchal mode of thinking founded on prehistoric anthropocentricism: a worldview embedded mostly in western cultures which considers (normal 1 ) human beings to be superior to nature and has often resulted in victimization of the so-called other. Haraway’s cyborg is capable of “becoming” animal or machine and is, hence, better suited to the Posthuman world. Following in Haraway’s footsteps, we intend to discuss that autistic people – labeled/stigmatized as intellectually disabled – are able bodies that share close affinities with animals, robots, nature, and environment. To this purpose, Sabina Berman’s debut novel Me, Who Dove into the Heart of the World (2012) 2 is examined to help us draw an analogy between a cyborg figure and an autistic body to bring to light the necessity of inclusion of all as prescribed by Posthumanism.

Ancient cattle DNA provides novel insight into the subsistence mode transition from the late Neolithic to Bronze Age in the Nenjiang River Basin

The Honghe site (Heilongjiang Province, Northeast China) is located in the middle reaches of the Nenjiang River Basin, which situates rich cultural relics and faunal remains dating between the Neolithic and Bronze ages. The site hosts abundant bovine genus remains that are ideal for exploring the genetic history of the bovid species and the subsistence mode of the populations there. In this study, we recovered 14 mitochondrial genomes from 16 bovid samples selected for ancient DNA analysis. Phylogenetic analysis identified them as aurochs (Bos primigenius) and taurine cattle (Bos taurus), with one in eight Neolithic samples belonging to haplogroup T3, the most common type of domesticated cattle in ancient China. The remainder clustered with haplogroup C, found only in Chinese aurochs, while haplogroups C and T3 in six Bronze Age samples accounted for 50% each. Hence, it was speculated that domesticated cattle might have arisen in the middle reaches of the Nenjiang River Basin around 4000 years ago. However, the C-type aurochs remained among the essential resources for cattle production at the Angangxi people's disposal until the Bronze Age. Moreover, more T3-type taurine cattle were introduced during the Bronze Age. These domesticated cattle shared haplotypes with ancient cattle from the Northwest and Central Plains, showing close affinities, thus, reflecting frequent and extensive correlation between the middle reaches of the Nenjiang River and other regions.

Genetic history of East-Central Europe in the first millennium CE

BackgroundThe appearance of Slavs in East-Central Europe has been the subject of an over 200-year debate driven by two conflicting hypotheses. The first assumes that Slavs came to the territory of contemporary Poland no earlier than the sixth century CE; the second postulates that they already inhabited this region in the Iron Age (IA). Testing either hypothesis is not trivial given that cremation of the dead was the prevailing custom in Central Europe from the late Bronze Age until the Middle Ages (MA).ResultsTo address this problem, we determined the genetic makeup of representatives of the IA Wielbark- and MA Slav-associated cultures from the territory of present-day Poland. The study involved 474 individuals buried in 27 cemeteries. For 197 of them, genome-wide data were obtained. We found close genetic affinities between the IA Wielbark culture-associated individuals and contemporary to them and older northern European populations. Further, we observed that the IA individuals had genetic components which were indispensable to model the MA population.ConclusionsThe collected data suggest that the Wielbark culture-associated IA population was formed by immigrants from the north who entered the region of contemporary Poland most likely at the beginning of the first millennium CE and mixed with autochthons. The presented results are in line with the hypothesis that assumes the genetic continuation between IA and MA periods in East-Central Europe.

Identification of the Late Devonian back-arc magmatism in the Chinese Eastern Tianshan

Identifcation of subduction to back-arc tectonic transitions is critical to the study of accretionary orogens. Some new geochronological and geochemical data for the Late Devonian (380–361 Ma) Kezier mafic–felsic complex and Tuwu granitic pluton in this study have well recorded such transition feature in the Chinese Eastern Tianshan orogen. The Kezier gabbro is classified as high-Al basalt given their high Al contents (A12O3 > 17 wt%). They were originated from a depleted mantle fluxed by fertile mantle components at shallow depths under hydrous condition. Both the Kezier and Tuwu granites show geochemical characteristics of high total alkali, Ga/Al, HFSE, low CaO, and strongly negative Ba, Sr, and Eu anomalies, demonstrating a close affinity with A-type granites. The granites were probably generated by high temperature melting (zircon saturation temperature up to 916 °C) of crustal rocks under a low-pressure (<0.8–1.0 GPa) condition. These rocks can help identify the Late Devonian back-arc extensional event in the Eastern Tianshan. This extensional event contemporaneous with the onset of the earliest arc magmatic records southward rejuvenating. The back-arc extensional with crustal high-temperature melting event can be reconciled with the Kangguer Ocean rollback, which forced the arc rifting occur on the Dananhu fore-arc side during the Late Devonian.

A new species of cirri-bearing eel of the genus Cirrhimuraena (Anguilliformes: Ophichthidae) from the coastal Bay of Bengal, India.

A new species of cirri-bearing ophichthidae eel Cirrhimuraena odishaensis sp. nov. is described here, on the basis of two specimens collectedfrom the Palur canal and Talasari fish landing centre in Odisha, India. The distinguishing characters of Cirrhimuraena odishaensis sp. nov. that separate it from its congeners include the presence of a single row of mandibular teeth, origin of the dorsal fin directly above the midpoint of pectoral fin, vertebral counts (pre-dorsal 10, pre-anal 46-47, and total 160-162), and number of cirri (13) on the upper jaw. Morphologically Cirrhimuraena odishaensis shows close affinity with Cirrhimuraena yuanding and Cirrhimuraena orientalis. The new species differs from C. yuanding by origin of dorsal fin, number of intermaxillary and maxillary teeth, and length of head. The new species differs from C. orientalis with relatively higher vertebrae.

Crotalaria heteromorpha (Leguminosae, Papilionoideae), a new species of the trifoliolate crotalarias group from the state of Guerrero, Mexico

Crotalaria heteromorpha, a new species from the state of Guerrero, Mexico, is described and illustrated on the basis of vegetative and floral features, and compared to related species. It seems to have a close affinity with C. filifolia. The new species differs from C. filifolia by having variation in the shape of the leaflets, the leaflet margins frequently reddish-brown, with variable pubescence on the upper side, longer stipules, shorter pedicels, comparatively smaller and reflexed wings, a narrower keel with a slightly larger and narrower beak and darker seeds, which are rough-grained in texture. With the proposal of C. heteromorpha as a new species, there are now 10 endemic trifoliolate species of Crotalaria recognized in México.

New insects (Paoliida, Dictyoptera) from the Carboniferous outcrop of Tante Victoire in Var, France

We introduce a novel paoliid, Carbonidelia gallica gen. et sp. nov., which may share close affinities with the ‘ideliid’ genus Sojanidelia Storozhenko, 1992. This new taxon is described from Gzhelian strata exposed at Tante Victoire in Var, France. Additionally, we present a remarkably well-preserved forewing from the same outcrop belonging to the phyloblattid genus and species Anthracoblattina ensifer cf. ‘variety desguini’. This species was previously known from the Gzhelian of Commentry in Allier, France. Therefore, this finding strengthens the Gzhelian age derived from the study of the palaeoflora at this outcrop. In this study, we also briefly delve into the inter- and intraspecific variability in the forewing venation of the ‘Anthracoblattina gigantea-ensifera group’. Furthermore, we challenge the classification of two Mesozoic roachoids, Sobytie tungusicum Vršanský, 2010 and Pozabudnutie antiquorum Hinkelman and Vršanský, 2022, which, in our view, do not belong to the Phyloblattidae family. Instead, they should be regarded as Dictyoptera of uncertain family affinities. A comprehensive revision of these species will be necessary to establish their precise taxonomic positions. André Nel [ anel@mnhn.fr ], Romain Garrouste [ romain.garrouste@mnhn.fr ], Corentin Jouault [ jouaultc0@gmail.com ], Institut de Systématique, Évolution, Biodiversité (ISYEB) Muséum national d’Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, CP50, 45 rue Buffon 75005, Paris, France; Univ. Rennes, CNRS, Géosciences Rennes, UMR 6118, F-35000, Rennes, France; Institut des Sciences de l’Évolution (UMR 5554), Université de Montpellier, CNRS, F-34095 Montpellier, France.

Petrogenesis of the Katangan mafic rocks, Zambia: Insights from lithogeochemistry, large igneous province classification, and petrological modeling

The Neoproterozoic Katangan mafic rocks are composed of gabbro and basalt sills, dykes, and flows. They are characterized as a large igneous province distributed throughout the 450 km long and 600 km wide arcuate Central African Copperbelt (CACB), and are in southeastern Democratic Republic of Congo and northwestern Zambia. Understanding the petrogenesis of these mafic intrusive rocks is vital to assist future studies, as examples regarding their relation to the vast Cu and Co deposits in the Central African Copperbelt or consequences of Rodinia's break up. Lithogeochemical data suggest that these rocks were formed due to an extensional regime developed during the rifting stage of the CACB, which resulted in the upwelling of the asthenospheric mantle. Consequently, petrological modeling demonstrated how these rocks derived from primitive magmas and evolved chemically through fractional crystallization, assimilation, and magma mixing, generating a range of compositions with close chemical affinity. Based on this analysis, we have subdivided them into two main groups with distinct sources each further subdivided into two subgroups. A voluminous group with ocean island basalt (OIB) affinities is widespread throughout the basin and can be modeled as the product of crustal assimilation by a picritic magma, concomitant with fractional crystallization. Magma types of this group have interacted with upper crust to develop a characteristic high Th/Ti trace element character. A less common magma represents the product of interactions between a tholeiite with enriched mid-ocean ridge (E-MORB) affinity with metasomatized subduction zone-modified lithospheric mantle (SZLM) to generate an array of moderately to extremely potassic magmas, which we classify as shoshonitic to ultrapotassic.

Translation and Transmission

Translation and Transmission

Popularization of Slovak Folk Tales in Poland

The reflection about research on Slavic folklore must be accompanied by a careful reminder that in the 19th century many people showed general interest in it and carried out field studies: these were amateurs, travellers, journalists and professional gatherers, i.e. ethnologists, and in the 20th century – folklorists (who continued the earlier work following accepted scientific curricula). The close linguistic affinity of the Slavs, similarity of political situations and social structures of folklore depositaries throughout history facilitated and developed comparative research on various folklore genres (tales, songs, legends, proverbs, comic stories). In the 19th century, Slovak songs were distinguished by Oskar Kolberg. Conversely, a concrete example of pioneering academic achievements in folk tale studies in Slovakia includes the tales collected by Pavol Dobšinský and Samuel Czambel, and later (in the first half of the 20th century) by Frank Wollman and his followers; and after World War II – by Viera Gašpariková. Many integrative, interethnic and comparative research initiatives have been directly linked to the tales and resulted in printing valuable collections of texts edited by folklorists from Poland and Slovakia e.g. Śpiewająca lipka. Bajki Słowian Zachodnich (The Singing Linden Tree. The Tales of the West Slavs), Zbójnicki dar. Polskie i słowackie opowiadania tatrzańskie (The Robber’s Gift. Polish and Slovak Stories about the Tatras), Słoneczny koń. Bajki słowackie (The Sunny Horse. Slovak Tales), Skarb w garncu. Humor ludowy Słowian Zachodnich (The Treasure in the Pot. Folk Humour of the West Slavs), Bajki słowackie (Slovak Tales by P. Dobšinský). According to the author of the article, Polish and Slovak work in the field of tales stands out among the research on folklore genealogy of the Slavs. Therefore, she focuses on the anthologies that promote and popularize Slovak tales in Poland.

RE-VISITING ACT EAST POLICY AND NORTHEAST INDIA: A VIEW FROM THE PERIPHERY

Northeast India's geo-strategic location and natural resources make it an important factor in India's Act East (AEP). The region extensive international border connects with neighbouring countries in South and Southeast Asia, and this has potential for a thriving border trade. Moreover, ethnically and culturally, the region enjoys close affinity with Southeast Asian countries. These cross-cultural affinities as well as the geo-strategic location of the region provide a rich incentive for India to strengthen close ties with Southeast Asian nations. However, the region has been deliberated upon in various ways, both through academic and non-academic prisms. Some perceive it as a volatile region with internecine ethnic conflicts and insurgency movements that shape the region’s socio-political landscape, while others perceive it as a region endowed with high potential for economic development. Of late, the region has been a recipient of generous financial grants disbursed by the central government, but nevertheless, it remains one of the most backward regions in the country, marked by acute unemployment and poverty despite being potentially rich in natural resources.

Tracing the introduction of Dictyota acutiloba (Dictyotales, Phaeophyceae) in the Mediterranean Sea, with a reassessment of its geographic distribution

ABSTRACT In this study we explore the introduction of the brown alga Dictyota acutiloba in the Mediterranean Sea and provide a substantive update on the geographic distribution of this species, which was long thought to be confined to the Pacific Ocean. A critical assessment of published distribution records and additional identifications based on cox1, psbA and rbcL genetic markers confirm the presence of D. acutiloba at a number of locations in the Indo-Pacific as well as three locations along the Israeli coastline in the south-eastern Mediterranean Sea. The close genetic affinity between introduced specimens and those from a population in Hurghada (Red Sea) strongly suggests an introduction via the Suez Canal. The occurrence of D. acutiloba in these regions is further supported by predictions made by correlative ecological niche models (ENMs), which show high suitability values in the northern Red Sea and the Levantine Basin. In contrast, environmental conditions in the western Mediterranean and parts of the north-eastern Mediterranean are currently less favourable, as evidenced by the lower predicted probability of occurrence. Under future scenarios, the suitability of these regions increases. The further spread of D. acutiloba in the eastern Mediterranean seems imminent, and the species may even extend its range to the western Mediterranean Sea, depending on the climate change scenario considered. While D. acutiloba can be relatively easily distinguished from the majority of Mediterranean Dictyota species, it remains difficult to differentiate this species from narrow growth forms of D. dichotoma. Therefore, we recommend the use of molecular markers such as cox1, psbA and rbcL, to unequivocally identify this species and monitor its further spread.

Teeth and tooth whorls of the stem chondrichthyan Doliodus from the Early Devonian of the Gaspé Sandstone Group, Gaspé Peninsula, Quebec, Canada

The Early Devonian (Emsian) vertebrate fauna of the Gaspé Peninsula, Quebec (Canada) shows close affinity with the Emsian fauna from the Atholville beds, New Brunswick (Canada). Specimens collected in the early 2000s from several localities in central Gaspé include molds of tooth whorls and isolated teeth that we assign to the stem chondrichthyan Doliodus. Isolated teeth of this taxon were first described from the Atholville beds in the late 1800s by Arthur Smith Woodward, who erected a new species Diplodus problematicus. Whereas the Atholville beds teeth are usually preserved individually or in tooth families, and as hard tissue, the Gaspé teeth are mostly preserved as molds of tooth whorls, with individual teeth sharing a thin bone base. Thin sections of Doliodus teeth from the Atholville beds show parallel close-set vascular canals extending above the base plate and through tooth bases, with teeth formed of osteodentine and meso- or orthodentine. We consider that all the known dental elements assigned to Doliodus are conspecific with the articulated Doliodus specimen and thus all are assigned to the same species D. latispinosus. The teeth are compared with the diplodont teeth of other stem chondrichthyan taxa, in particular the Omalodontiformes.