Basal Relationships Research Articles

Motor performance and functional connectivity between the posterior cingulate cortex and supplementary motor cortex in bipolar and unipolar depression.

Although implicated in unsuccessful treatment, psychomotor deficits and their neurobiological underpinnings in bipolar (BD) and unipolar (UD) depression remain poorly investigated. Here, we hypothesized that motor performance deficits in depressed patients would relate to basal functional coupling of the hand primary motor cortex (M1) and the posterior cingulate cortex (PCC) with the supplementary motor area (SMA). We performed a longitudinal, naturalistic study in BD, UD and matched healthy controls comprising of two resting-state functional MRI measurements five weeks apart and accompanying assessments of motor performance using a finger tapping task (FTT). A subject-specific seed-based analysis describing functional connectivity between PCC-SMA as well as M1-SMA was conducted. The basal relationships with motor performance were investigated using linear regression models and all measures were compared across groups. Performance in FTT was impaired in BD in comparison to HC in both sessions. Behavioral performance across groups correlated significantly with resting state functional coupling of PCC-SMA, but not of M1-SMA regions. This relationship was partially reflected in a reduced PCC-SMA connectivity in BD vs HC in the second session. Exploratory evaluation of large-scale networks coupling (SMN-DMN) exhibited no correlation to motor performance. Our results shed new light on the association between the degree of disruption in the SMA-PCC anticorrelation and the level of motor impairment in BD.

Early evolution of the megadiverse subtribe Philonthina (Staphylinidae: Staphylininae: Staphylinini) and its Neotropical lineage

AbstractPhilonthina (2864 species in 74 genera) represents almost one‐half of the diversity of Staphylinini and is the largest of its subtribes. Most Philonthina species are found in tropical areas, but the origin of this diversity is still not well understood, mainly because their systematics belongs to a past era of taxonomy. Such is the case of a group of genera, most of them endemic to the Neotropical region (NT), whose monophyly has been repeatedly confirmed and which constitutes the so‐called Neotropical lineage (NL). However, basal relationships have not been clarified, neither for Philonthina nor its NL. The NL includes ∼300 species and 26 genera, but two of them (Belonuchus Nordmann and Paederomimus Sharp) account for two‐thirds of its species. Here, using the largest molecular‐based phylogeny of Philonthina and its NL to date, a time‐calibrated phylogeny, and ancestral range reconstructions for the NL, we explore the evolutionary history of Philonthina with a focus on its NL to reveal their early evolution and diversification in the NT. We show that Philonthina originated during the Late Cretaceous ∼ 67.6 Ma and diversified into five main lineages mostly during the Eocene. The NL originated in northwestern South America (SA) and the Andes not earlier than 64.2 Ma from a Laurasian lineage present in SA ∼49.1–69.9 Ma. Shortly afterward, that is, 39.9–56.9 Ma, the NL diversified into the Andean clade and the most species‐rich Belonuchus‐Paederomimus group. Our analyses recover northwestern SA and the Andes as the primary centers of diversification. Dispersal events to the northern landmasses took place at least three times during the Miocene in the early evolution of the NL.

Mitogenomic phylogeny of nymphalid subfamilies confirms the basal clade position of Danainae (Insecta: Lepidoptera: Nymphalidae).

The phylogenetic relationships among the nymphalid subfamilies have largely been resolved using both morphological and molecular datasets, with the exception of a conflicting basal clade position for Libytheinae or Danainae that remains contentious between morphological and molecular studies. Several phylogenomic analyses have found that the danaine clade is sister to other nymphalid subfamilies; however, it largely depends on utilizing different molecular datasets, analysis methods, and taxon sampling. This study aimed to resolve the basal clade position and relationships among subfamilies and tribes of Nymphalinae by combining the most comprehensive available mitogenomic datasets with various analyses methods by incorporating a new Symbrenthia lilaea Hewitson sequence data. Phylogenetic relationships among 11 nymphalid subfamilies and the tribes of Nymphalinae were inferred by combining new and available mitogenomic sequence data from 80 ingroup and six outgroup species. The phylogenetic trees were reconstructed using maximum-likelihood (ML) and Bayesian inference (BI) methods based on five concatenated datasets: amino acid sequences and nucleotides from different combinations of protein-coding genes (PCGs), ribosomal RNA (rRNAs), and transfer RNA (tRNAs). Danainae is well-supported as the basal clade and sister to the remaining nymphalid subfamilies, except for the paraphyletic Libytheinae. Libytheinae was either recovered as a sister to the danaine clade followed by the satyrine clade or sister to the nymphaline + heliconiine clades, and is consistent with recent phylogenetic studies on Nymphalidae. The monophyletic Nymphalinae has been recovered in all analyses and resolves tribal-level relationships with high support values in both BI and ML analyses. We supported the monophyletic Nymphalini as a sister clade to Victorini, Melitaeini, and Kallimini + Junoniini with high supporting values in BI and ML analyses, which is consistent with previously published morphological and molecular studies.

Phylogenomic resolution of Imparidentia (Mollusca: Bivalvia) diversification through mitochondrial genomes.

The online version contains supplementary material available at 10.1007/s42995-023-00178-x.

Molecular and biometric data on Carabus (Macrothorax) morbillosus Fabricius, 1792 (Coleoptera, Carabidae) from Mid Mediterranean areas.

The present study was carried out using molecular and biometric data of Carabus (Macrothorax) morbillosus from mid-Mediterranean areas to determine additional information on basal relationships among its representative subspecies. To this aim, two different kinds of approach were employed, including a morphometric analysis of four morphological parameters (i.e., elytra length, elytra width, pronotum length, pronotum width) of 128 specimens, and a Bayesian genetic analysis of 44 cytochrome oxidase subunit I (COI) partial sequences (i.e., 38 examined for the first time and six retrieved from GenBank database). Representative populations of C. (M.) morbillosus were sampled in four countries, namely Italy, Malta, Spain, and Tunisia. The present findings support the validity of four C. (M.) morbillosus subspecies, specifically C. (M.) m. alternans, C. (M.) m. bruttianus, C. (M.) m. constantinus, and C. (M.) m. macilentus, and redefine these subspecies' distributions. Notably, within the C. (M.) m. constantinus clade, two (i.e., Sardinia/Tuscany and Lampedusa) out of the three subgroups appear as homogeneous geographical groupings.

Discovery of the Genus Anapleus Horn, 1873 from Cretaceous Kachin Amber (Coleoptera: Histeridae).

Simple SummaryHistorically, researchers have suggested different resolutions of the basal relationships of the family Histeridae based on various datasets and methods of phylogenetic analysis. Phylogenetic analyses combining extant and fossil forms will doubtlessly shed further light on its early evolution. The present study describes the first fossil Anapleus species from mid-Cretaceous Kachin amber. This new discovery enriches the fossil record of histerid beetles and has important implications for efforts to understand their early evolutionary history.For the first time, an extant histerid genus Anapleus Horn, 1873 is described from a specimen found in mid-Cretaceous Kachin amber. Anapleus kachinensis sp. nov. Although the genus Anapleus has not been precisely defined by synapomorphies, the new species shares numerous features with extant species while differing in comparatively few external characteristics. Anapleus kachinensis represents the first record of an extant histerid genus from Cretaceous deposits and provides further evidence of the ancient origin of the genus.

Basal and dynamic relationships between serum anti-Müllerian hormone and gonadotropins in patients with functional hypothalamic amenorrhea, with or without polycystic ovarian morphology

BackgroundTo evaluate in women with functional hypothalamic amenorrhea (FHA), whether there is a difference between patients with and without polycystic ovarian morphology (PCOM) concerning the response to a gonadotropin releasing hormone (GnRH) stimulation test and to pulsatile GnRH treatment.MethodsIn a retrospective observational study, 64 women with FHA who underwent a GnRH stimulation test and 32 age-matched controls without PCOM were included. Pulsatile GnRH treatment was provided to 31 FHA patients and three-month follow-up data were available for 19 of these.ResultsSerum levels of gonadotropins and estradiol were lower in FHA women than in controls (p < 0.05). FHA patients revealed PCOM in 27/64 cases (42.2%). FHA patients without PCOM revealed lower anti-Müllerian hormone (AMH) levels than controls (median 2.03 ng/mL, IQR 1.40–2.50, versus 3.08 ng/mL, IQR 2.24–4.10, respectively, p < 0.001). Comparing FHA patients with and without PCOM, the latter revealed lower AMH levels, a lower median LH increase after the GnRH stimulation test (240.0%, IQR 186.4–370.0, versus 604.9%, IQR 360.0–1122.0; p < 0.001) as well as, contrary to patients with PCOM, a significant increase in AMH after three months of successful pulsatile GnRH treatment (median 1.69 ng/mL at baseline versus 2.02 ng/mL after three months of treatment; p = 0.002).ConclusionsIn women with FHA without PCOM, the phenomenon of low AMH levels seems to be based on relative gonadotropin deficiency rather than diminished ovarian reserve. AMH tended to rise after three months of pulsatile GnRH treatment. The differences found between patients with and without PCOM suggest the former the existence of some PCOS-specific systemic and/or intra-ovarian abnormalities.

Abstract 2202: Contiguous airway sampling for basal cell isolation

Abstract Introduction: Airway basal cells isolated from histologically normal epithelium in current and former smokers demonstrate a significantly higher mutation burden than those in never-smokers. However, a proportion of basal cells with lower (“near normal”) mutation burden are observed, which show preferential expansion in response to smoking cessation(1). We believe this expansion represents a “cancer protective” process, reducing the risk of future malignancy. However, mechanisms determining the dynamic balance of high versus low mutant basal cells throughout the bronchial tree are unclear. We have developed protocols that enable systematic scanning of airway epithelium in resected lung specimens, through which we aim to elucidate the mutation burden and spatial clonal architecture across contiguous regions of normal epithelium through the bronchial tree. Study design: 5-10 current or former smokers undergoing curative lobectomy for peripheral lung cancer with histologically normal airways will be consented to the study. To date, two participants have donated their samples. Fresh lobectomies were collected at the point of resection and kept on wet ice until pathological examination. All samples undergo examination within 1 hour of resection. The lobe is orientated, and the tumour and segmental bronchi identified. A sterile metal cannula is inserted through the airway lumen and sterile pathology scissors are used to carefully isolate the airways from the surrounding parenchyma. Upon macro-dissection, airway branches are immediately placed into transport media containing antibiotics. Samples are gently washed using transport media to remove residual blood, then sectioned into 1 cm3 segments, which are orientated, embedded and frozen in room-temperature Optimal Cutting Temperature compound. An 8 μM section is cut and stained with haematoxylin and eosin from each block immediately after a “full-face” tissue confirmation is observed.These will be used as guiding slides for laser capture microdissection of the regions of epithelium prior to downstream sequencing pathway. Conclusion: We have developed a pathological approach in which we can define somatic mutations in normal epithelium along the bronchial tree. We will use these data to determine basal cell clonal relationships and interpret these in a spatial context, creating a more detailed map of the smoking-induced changes that occur in the airway epithelium and how these may contribute to early carcinogenesis.

Host Shift Speciation of the Ectomycorrhizal Genus Suillus (Suillineae, Boletales) and Biogeographic Comparison With Its Host Pinaceae.

Suillus is a genus of ectomycorrhizal fungi associated almost exclusively with Pinaceae. Lack of sample collections in East Asia and unresolved basal phylogenetic relationships of the genus are the major obstacles for better understanding the Suillus evolution. A resolved phylogeny of Suillus representing global diversity was achieved by sequencing multiple nuclear ribosomal and protein coding genes and extensive samples collected in East Asia. Fungal fossils are extremely rare, and the Eocene ectomycorrhizal symbiosis (ECM) fossil of Pinus root has been widely used for calibration. This study explored an alternative calibration scenario of the ECM fossil for controversy. Ancestral host associations of Suillus were estimated by maximum likelihood and Bayesian Markov chain Monte Carlo (MCMC) analyses, inferred from current host information from root tips and field observation. Host shift speciation explains the diversification of Suillus major clades. The three basal subgenera of Suillus were inferred to be associated with Larix, and diverged in early Eocene or Upper Cretaceous. In the early Oligocene or Paleocene, subgenus Suillus diverged and switched host to Pinus subgenus Strobus, and then switched to subgenus Pinus four times. Suillus subgenus Douglasii switched host from Larix to Pseudotsuga in Oligocene or Eocene. Increased species diversity occurred in subgenus Suillus after it switched host to Pinus but no associated speciation rate shifts were detected. Ancestral biogeographic distributions of Suillus and Pinaceae were estimated under the Dispersal Extinction Cladogenesis (DEC) model. Ancestral distribution patterns of Suillus and Pinaceae are related but generally discordant. Dispersals between Eurasia and North America explain the prevalence of disjunct Suillus taxa.

Gene-tree misrooting drives conflicts in phylogenomic coalescent analyses of palaeognath birds

Phylogenomic analyses of ancient rapid radiations can produce conflicting results that are driven by differential sampling of taxa and characters as well as the limitations of alternative analytical methods. We re-examine basal relationships of palaeognath birds (ratites and tinamous) using recently published datasets of nucleotide characters from 20,850 loci as well as 4301 retroelement insertions. The original studies attributed conflicting resolutions of rheas in their inferred coalescent and concatenation trees to concatenation failing in the anomaly zone. By contrast, we find that the coalescent-based resolution of rheas is premised upon extensive gene-tree estimation errors. Furthermore, retroelement insertions contain much more conflict than originally reported and multiple insertion loci support the basal position of rheas found in concatenation trees, while none were reported in the original publication. We demonstrate how even remarkable congruence in phylogenomic studies may be driven by long-branch misplacement of a divergent outgroup, highly incongruent gene trees, differential taxon sampling that can result in gene-tree misrooting errors that bias species-tree inference, and gross homology errors. What was previously interpreted as broad, robustly supported corroboration for a single resolution in coalescent analyses may instead indicate a common bias that taints phylogenomic results across multiple genome-scale datasets. The updated retroelement dataset now supports a species tree with branch lengths that suggest an ancient anomaly zone, and both concatenation and coalescent analyses of the huge nucleotide datasets fail to yield coherent, reliable results in this challenging phylogenetic context.

The Allelic Variants in Microsatellite Loci and Phylogenetic Relationships of &lt;i&gt;Darevskia rudis&lt;/i&gt; (Bedriaga, 1886) and &lt;i&gt;D. bithynica&lt;/i&gt; (Méhely, 1909) Based on Mitochondrial DNA in Turkey

The spiny-tailed lizard, which has a series of taxonomic revisions, is one of the most common lizard species in Turkey. In this study, sequence data derived from three microsatellite loci (Du215, Du281, and Du323), two mitochondrial (16S rRNA and Cyt-b) genes and combined data were used to evaluate the taxonomic status of Darevskia rudis and Darevskia bithynica with new samples from all subspecies populations in Turkey. Our results indicated that the genetic variations of microsatellite loci were not specific to populations within species, and only minor differences separated D. rudis and D. bithynica populations. Furthermore, the markers we used for phylogenetic analyses (NJ, ML, MP, and BI) produced topologically similar trees based on 16S rRNA and Cyt-b while the combined data produced conflicting trees with the separate gene analyses. Finally, the basal relationships among the populations in Turkish populations D. rudis and D. bithynica were not resolved with this dataset, and we found a hard polytomy at the basis of the phylogeny.

First Complete Mitochondrial Genome of a Tanaidacean Crustacean (Arctotanais alascensis).

We present a complete mitochondrial genomic sequence for the tanaidacean Arctotanais alascensis (Richardson, 1899); this is the first complete mitogenome reported from the order Tanaidacea. The mitogenome is 13,988 bp long and contains 13 protein coding and two ribosomal RNA genes (as is typical for animal mitogenomes), and 21 of 22 transfer RNAs; we did not detect an isoleucine transfer RNA (trnI) gene. The gene order differed markedly from the hypothetical ground pattern for Pancrustacea; only four clusters (trnM + nad2; trnC + trnY + cox1 + trnL2 + cox2; trnD + atp8 + atp6 + cox3; trnH + nad4 + nad4l) ancestrally present were retained. In a malacostracan phylogenetic tree reconstructed from mitogenome data, basal relationships were marginally supported or incongruent with the traditional morphology-based classification and the latest phylogenetic reconstructions from large transcriptomic datasets. Relationships involving more recent divergences were better supported in our tree, suggesting that complete mitogenome sequences are more suitable for phylogenetic analyses within malacostracan orders, presumably including Tanaidacea.

A transitional fossil sheds light on the early evolution of the Staphylinine group of rove beetles (Coleoptera: Staphylinidae)

Rove beetles of the Staphylinine group of subfamilies represent the most species-rich clade of Staphylinidae, which in turn is the most speciose beetle family. While several relationships within the Staphylinine group are well supported by morphological and molecular data alike, the basal relationships within the clade remain unresolved. In particular, understanding the largest radiation on the beetle tree of life is complicated by the absence of early-diverging transitional fossils. Here we describe a new genus and species of the Staphylinine group of subfamilies from the Lower Cretaceous Yixian Formation in eastern China (c. 125 Ma). Paroxyporus fossilis Cai gen. et sp. nov. shares a number of characters with the monogeneric subfamily Oxyporinae, namely its prognathous head with prominent apically curved mandibles, contiguous procoxae, moderately separated mesocoxae and abdominal intersegmental membranes with a ‘brick-wall’ pattern. It, however, shares oval procoxae and ‘U’-shaped abdominal impressions with the monogeneric subfamily Megalopsidiinae. A parsimony analysis of 211 morphological characters recovered Paroxyporus gen. nov. as sister to the whole Staphylinine group except Oxyporinae, linking Oxyporinae and other clades of the Staphylinine group, and it seems to be a stem member of the Staphylinine group. As such, Paroxyporus gen. nov. may represent an early-diverging isolated lineage within the Staphylinine group, a lineage that has been recognized on the basis of morphological data but challenged by some recent molecular studies, or alternatively a stem member of the Staphylinine group. Together with described fossil members of the subfamily Oxyporinae, Paederine and Staphylinine from the Yixian Formation, Paroxyporus fossilis gen. et sp. nov. is one of the earliest representatives of the Staphylinine group in the fossil record, providing an important calibration point for understanding the timing of the early diversification of rove beetles in the Mesozoic. http://zoobank.org/urn:lsid:zoobank.org:pub:40F8F256-7E9F-478E-AC96-1EB1BCE5A02B

Higher-level phylogenetic relationships of rove beetles (Coleoptera, Staphylinidae) inferred from mitochondrial genome sequences

Rove beetles (Staphylinidae) and allied families constitute a huge radiation of Coleoptera, but basal relationships in this group remain controversial. In this study, we newly sequenced eight mitogenomes of representatives of Staphylinidae by using next-generation sequencing method. Together with 99 existing mitogenomes of Staphyliniformia, (sub)family relationships were investigated with ML and Bayesian searches under various substitution models and data recoding schemes. The results consistently supported Scydmaenidae and Silphidae to be subordinate groups of Staphylinidae. Within the monophyletic Staphylinidae (including Scydmaenidae and Silphidae), the hypothesis of four major subfamily groups cannot be confirmed. Bayesian inferences under the site-heterogeneous mixture model generally supported the basal position of major clades corresponding to the Omaliine group. At the subfamily level, the monophyly of Pselaphinae, Oxytelinae, Scaphidiinae, Steninae and Staphylininae was supported. However, the subfamilies Omaliinae, Tachyporinae, Aleocharinae and Paederinae were each non-monophyletic.

Phylogeny of hymenolepidids (Cestoda: Cyclophyllidea) from mammals: sequences of 18S rRNA and COI genes confirm major clades revealed by the 28S rRNA analyses.

The aim of the study is to test a hypothesis for the phylogenetic relationships among mammalian hymenolepidid tapeworms, based on partial (D1-D3) nuclear 28S ribosomal RNA (rRNA) genes, by estimating new molecular phylogenies for the group based on partial mitochondrial cytochrome c oxidase I (COI) and nuclear 18S rRNA genes, as well as a combined analysis using all three genes. New sequences of COI and 18S rRNA genes were obtained for Coronacanthus integrus, C. magnihamatus, C. omissus, C. vassilevi, Ditestolepis diaphana, Lineolepis scutigera, Spasskylepis ovaluteri, Staphylocystis tiara, S. furcata, S. uncinata, Vaucherilepis trichophorus and Neoskrjabinolepis sp. The phylogenetic analyses confirmed the major clades identified by Haukisalmi et al. (Zoologica Scripta 39: 631-641, 2010): Ditestolepis clade, Hymenolepis clade, Rodentolepis clade and Arostrilepis clade. While the Ditestolepis clade is associated with soricids, the structure of the other three clades suggests multiple evolutionary events of host switching between shrews and rodents. Two of the present analyses (18S rRNA and COI genes) show that the basal relationships of the four mammalian clades are branching at the same polytomy with several hymenolepidids from birds (both terrestrial and aquatic). This may indicate a rapid radiation of the group, with multiple events of colonizations of mammalian hosts by avian parasites.

Chloroplast genomes of key species shed light on the evolution of the ancient genus Isoetes

AbstractAlthough phylogenetic studies have revealed major clades, the deepest relationships in Isoetes remain unresolved. The use of next‐generation sequencing provides enormous amounts of gene sequences, which allows not only clarification of the basal relationships but also rapid radiations. Plastomes of six key Isoetes species were annotated, revealing a total of 129 or 130 genes, depending on the species. Our phylogenomic analyses comprising representatives of all major clades yielded well‐supported nodes and identical topologies using maximum likelihood and Bayesian inference. The phylogenetic reconstructions detangled the deep relationships in Isoetes and illuminated the more recent radiations in the genus. A basal dichotomy was found that grouped Isoetes spp. from Brazil and South Africa into a clade sister to the remaining Isoetes groups. Interestingly, I. andicola was found to be sister to the North American species complex. Genomic trait mapping analysis showed that the missing introns in the atpF and clpP genes were well conserved in two major clades. The absence of trnK‐UUU was observed in the Brazilian tropical species and in I. velata. Among lycophytes, the gene trnR‐CCG was missing only in I. eludens. In general, genomic traits such as the presence or absence of internal stop codons, a tRNA, and an intron were revealed to be conserved within groups, suggesting that these genomic traits might reveal vital information about the evolution of the genus. This study will contribute to understanding the diversification of Isoetes and the establishment of a better framework to address the evolutionary history of the genus.

Molecular phylogeny of the phytoparasitic mite family Phytoptidae (Acariformes: Eriophyoidea) identified the female genitalic anatomy as a major macroevolutionary factor and revealed multiple origins of gall induction.

Phytoptidae s.str. is a lineage of eriophyoid mites associated with angiosperms. Based on representative taxon sampling and four gene markers (COI, HSP70, 18S, and 28S), we inferred the molecular phylogeny of this group and performed comparative analyses of cuticle-lined female internal genitalia. Although basal relationships were unclear, several well supported clades were recovered. These clades were supported by geography, host associations, and female genital anatomy, but contradicted the current morphology-based systematics. The monophyly of each of five conventional supraspecific groupings (Fragariocoptes, Phytoptus, Phytoptinae, Sierraphytoptinae, and Sierraphytoptini) is rejected based on a series of statistical tests. Additionally, four morphological characters (the absence of tibial solenidion φ and opisthosomal seta c1, presence of telosomal pseudotagma, and 'morphotype') were found to be homoplasies that cannot be used to confidently delimit supraspecific lineages of phytoptids. However, our molecular topology was highly congruent with female genital characters. Eight molecular clades were unambiguously supported by the shapes and topography of the spermathecal apparatus and genital apodemes. This suggests that the female genital anatomy could be an important factor affecting cladogenesis in Phytoptidae, a conclusion contrasting with the general expectation that host characteristics should be a major macroevolutionary force influencing the evolution of host-specific symbionts. Indeed, despite the high host-specificity, there were no apparent cophylogenetic patterns. Furthermore, we show that gall-inducing ability evolved multiple times in phytoptids. Because gall formation creates nearly instantaneous niche partitioning and the potential loss or reduction of gene flow, we hypothesize that it could be an important evolutionary factor affecting speciation within different host-associated clades of phytoptid mites.

Earliest Embrithopod Mammals (Afrotheria, Tethytheria) from the Early Eocene of Morocco: Anatomy, Systematics and Phylogenetic Significance

We provide detailed morphological description, including enamel microstructure, of the earliest known embrithopod mammals (Afrotheria, Paenungulata), Stylolophus minor and S. major, n. sp., recently discovered in the early Eocene of the Ouled Abdoun phosphate basin, Morocco. Stylolophus minor and S. major, n. sp., show close morphological affinity, and the enamel microstructure supports their congeneric status. Stylolophus major, which comes from an upper level (middle Ypresian) of the Ouled Abdoun phosphate series, has more derived features than S. minor in addition to a larger size. This argues that S. minor and S. major are chronospecies. This new mammal lineage recognized in the Ouled Abdoun phosphate series is characterized by a rapid size increase, as for the proboscideans and probably in correlation with early-middle Ypresian global climatic warming events. We investigated relationships of Stylolophus in a new cladistic analysis based on an extended and revised matrix that includes new enamel microstructural features studied in Stylolophus. Resulting MPTs recover 1) basal relationships of Stylolophus within the Embrithopoda; 2) sister-group relationship of the Embrithopoda to the crown Tethytheria (Proboscidea, Sirenia); and 3) the clades Tethytheria and Paenungulata. It supports in particular that the order Embrithopoda is a basal tethytherian offshoot that rapidly evolved and specialized in parallel to the splitting and early evolution of extant tethytherian orders. Stylolophus shows that the ancestral embrithopod morphotype was already well specialized in the early Eocene and quite distinctive with respect to other paenungulates (e.g., hyperdilambdodonty, lingual hypoconulid, cristid obliqua very lingual on the trigonid, small and lingual hypoconulid lobe on M3, large paranasal sinuses, concave palate), even with respect to their earliest representatives. Stylolophus minor was larger than the contemporary proboscidean Phosphatherium escuilliei. Together with the stem tethytherian relationship of the Embrithopoda, it supports an old origin of the order, at least early in the Paleocene. This relationship is also most consistent with the evolution of the embrithopod hyperdilambdodont pattern from the dilambdodont and selenodont ancestral morphotype of the paenungulates, which is known in early hyracoids but not in proboscideans and sirenians, which have reduced the ectoloph. The most specialized embrithopods evolved hyperdilambdodonty in a pseudolophodont state in parallel to the true lophodonty of crown tethytherians. The Ouled Abdoun embrithopods further help indeed to show that the early Tertiary herbivorous niches of the African island favored convergent evolution of the folivorous diet in several paenungulate and tethytherian clades. At higher scale, convergence of African and Laurasian “ungulates” is supported by enamel microstructure of Stylolophus. The early and basalmost embrithopods S. minor and S. major, n. sp., are new evidence of the Arabo-African origin of the order.

A new phylogeny of cerapodan dinosaurs

ABSTRACT This work attempts at providing a revised framework for ornithischian phylogeny, based on an exhaustive data compilation of already published analyses, a critical re-evaluation of osteological characters and an in-depth checking of characters scoring to fix mistakes that have accumulated in previous analyses; we have also included recently described basal ornithischians, marginocephalians and ornithopods. ‘Heterodontosaurids’ are recovered as a paraphyletic group of basal Marginocephalia that progressively lead to the dome-headed ‘true’ pachycephalosaurs. ‘Heterodontosaurids’ consequently fall within Pachycephalosauria sensu Sereno, 1998. The reconfiguration of basal cerapodan relationships pulls the origins of ornithopods to the earliest stages of the Jurassic. Based on the present analysis, we also discuss ornithopod relationships, with a particular focus on basal Iguanodontia. Tenontosaurus is found as the basalmost iguanodontian. The monophyly of Rhabdodontomorpha in a position more derived than Tenontosaurus is supported by the present analysis.

A reevaluation of the basal turtle Indochelys spatulata from the Early-Middle Jurassic (Toarcian-Aalenian) of India, with descriptions of new material.

BackgroundIndochelys spatulata is an extinct turtle from the Early to Middle Jurassic Kota Formation of the Pranhita–Godavari Gondwana basin, India. The holotype and previously only known specimen is a partially eroded shell that had been collected near Kota village, north of Sironcha, in Maharashtra State. Phylogenetic analyses have consistently suggested placement at the base of the clade Mesochelydia.MethodsWe here figure and describe the holotype of Indochelys spatulata and two new specimens, which were collected from the Kota Formation near Kistapur village, Telengana State, about 60 km NW from the type locality. We furthermore explore the relationships of this fossil turtle by updating its scoring based on all available material in the most recent analysis of basal turtle relationships.ResultsThe revision of the holotype of Indochelys spatulata provides minor adjustments to the morphology of this specimen, in particular recognition of a transverse break across the carapace, presence of only eight neurals, of which the eight is octagonal, and presence of a pathological element located between neurals VII and VIII. The new material provides new anatomical insights, in particular presence of a broad cervical, a vertebral V that inserts deeply into vertebral IV, narrow pleurals within increasingly short posteromedial contacts with the vertebrals towards the posterior, at least three pairs of musk duct foramina, and numerous insights into the morphology of the girdles and stylopodium. In combination, all material allows affirming the validity of Indochelys spatulata with confidence. The phylogenetic analysis affirms the placement of Indochelys spatulata as a basal mesochelydian, but cannot resolve its relationships relative to the roughly coeval Condorchelys antiqua and Kayentachelys aprix.