Morphological and ecological diversity of Amebelodontidae (Proboscidea, Mammalia) revealed by a Miocene fossil accumulation of an upper-tuskless proboscidean

<p>Amebelodontidae is the most taxonomically and morphologically diverse group of proboscideans. However, relative to the morphological variation of the mandible and mandibular tusks, ecological and phylogenetic differentiations within Amebelodontidae have been largely debated. Here we evaluate a middle Miocene fossil accumulation of a new amebelodontid, <i>Aphanobelodon zhaoi</i> gen. et sp. nov. This species lacks upper tusks, which is unique in elephantiforms. The mandible and mandibular tusk morphologies of <i>A. zhaoi</i> are similar to those of the genus <i>Platybelodon</i>, which is the typical representative of one of the two main amebelodontid branches (the other branch is represented by <i>Amebelodon</i>). We suggest that <i>Amebelodon</i> potentially used its mandible and mandibular tusks to dig for food in relatively hard substrates; whereas <i>Platybelodon</i> is more specialized and possibly used its mandibular tusks for cutting soft vegetation. <i>Aphanobelodon zhaoi</i> morphology indicates that it is an offshoot of the platybelodont clade within Amebelodontidae, because it has primitive undifferentiated states of the mandible and mandibular tusks. Cladistic analysis indicates that <i>Aphanobelodon</i>, <i>Platybelodon</i> and <i>Torynobelodon</i> comprise a monophyletic group within Amebelodontidae. This study enhances our knowledge regarding proboscidean evolutionary history in terms of morphology, taxonomy and biology.</p> <p><a href="http://zoobank.org/urn:lsid:zoobank.org:pub:8F30BAC7-4245-4952-BFCF-884E3DB839F6" target="_blank">http://zoobank.org/urn:lsid:zoobank.org:pub:8F30BAC7-4245-4952-BFCF-884E3DB839F6</a></p

Lower dentition of <i>Proansomys dureensis</i>, sp. nov. A, IVPP V18533.19, Ldp4; B, V18534.16, Lp4; C, V18534.22, Lm1; D, V18535.1, Lm2; E, V18534.27, Rm3.

<p>Lower dentition of <i>Proansomys dureensis</i>, sp. nov. A, IVPP V18533.19, Ldp4; B, V18534.16, Lp4; C, V18534.22, Lm1; D, V18535.1, Lm2; E, V18534.27, Rm3.</p

Measurements in millimeters of the teeth of <i>Proansomys dureensis</i>, sp. nov.

<p>Measurements in millimeters of the teeth of <i>Proansomys dureensis</i>, sp. nov.</p

Transcriptome Profiling of Tomato Fruit Development Reveals Transcription Factors Associated with Ascorbic Acid, Carotenoid and Flavonoid Biosynthesis

<div><p>Tomato (<i>Solanum lycopersicum</i>) serves as a research model for fruit development; however, while it is an important dietary source of antioxidant nutrients, the transcriptional regulation of genes that determine nutrient levels remains poorly understood. Here, the transcriptomes of fruit at seven developmental stages (7, 14, 21, 28, 35, 42 and 49 days after flowering) from two tomato cultivars (Ailsa Craig and HG6-61) were evaluated using the Illumina sequencing platform. A total of 26,397 genes, which were expressed in at least one developmental stage, were detected in the two cultivars, and the expression patterns of those genes could be divided into 20 groups using a K-mean cluster analysis. Gene Ontology term enrichment analysis indicated that genes involved in RNA regulation, secondary metabolism, hormone metabolism and cell wall metabolism were the most highly differentially expressed genes during fruit development and ripening. A co-expression analysis revealed several transcription factors whose expression patterns correlated with those of genes associated with ascorbic acid, carotenoid and flavonoid biosynthesis. This transcriptional correlation was confirmed by agroinfiltration mediated transient expression, which showed that most of the enzymatic genes in the ascorbic acid biosynthesis were regulated by the overexpression of each of the three transcription factors that were tested. The metabolic dynamics of ascorbic acid, carotenoid and flavonoid were investigated during fruit development and ripening, and some selected transcription factors showed transcriptional correlation with the accumulation of ascorbic acid, carotenoid and flavonoid. This transcriptome study provides insight into the regulatory mechanism of fruit development and presents candidate transcription factors involved in secondary metabolism.</p></div

Location and overview of the Tieersihabahe locality.

<p>A, Location of the Tieersihabahe and Saerduoyila localities; B, close up of Tieersihabahe Formation where the fossils were found; C, Broad expanse of Tieersihabahe Section in the northern Junggar Basin. The black arrow in B above indicates the Tieersihabahe Formation.</p

Transcriptome dynamics in Ailsa Craig fruit during development.

<p>The log₂ value of reads per kilobase of a gene per million reads (RPKM) for each gene was used for the K-mean clustering analysis of each of the seven selected developmental stages (7, 14, 21, 28, 35, 42 and 49 days after flowering [DAF]). The 26,397 genes were grouped into 20 expression patterns. The designation is based on the nomenclature of the gene expression pattern.</p

SI 15. Tossunnoria pseudibex, IVPP RV37087 (No. 449), fragmentary brain case with both horncores.

SI 15. Tossunnoria pseudibex, IVPP RV37087 (No. 449), fragmentary brain case with both horncores

Three most parsimonious trees (MPTs 1–3) and their strict consensus tree.

<p>Three most parsimonious trees (MPTs 1–3) and their strict consensus tree.</p

A summary of stratigraphic positions and age estimates for major mammal assemblages of Tieersihabahe Section in the northern Junggar Basin, China.

<p>A summary of stratigraphic positions and age estimates for major mammal assemblages of Tieersihabahe Section in the northern Junggar Basin, China.</p

SI 14SI 14. Tossunnoria pseudibex, IVPP RV37086 (type specimen, No. 481), brain case with both horncores.

SI 14SI 14. Tossunnoria pseudibex, IVPP RV37086 (type specimen, No. 481), brain case with both horncores