Biology subjects

van Heteren, A. H.

Publications and source records attributed to van Heteren, A. H..

3 recordsLinked to original sources

bioRxiv2025

First Comprehensive Examination of the Molecular Phylogenetics of Saki Monkeys, Genus Pithecia Desmarest, 1804, Reveals an Unexpectedly Low Taxonomic Diversity

Saki monkeys (Pithecia) are found exclusively in the Amazon, ranging from the Guiana Shield in the east to the Andean foothills in the west. The taxonomy of this genus is complex due to indeterminate type localities, numerous synonyms, sexual dichromatism and considerable geographical diversity in coat colour patterns. Previous assessments have indicated two to four species and a variable few subspecies based on morphological analyses of museum specimens. Just two species have been consistently recognised--Pithecia pithecia and Pithecia monachus. This study presents the first comprehensive molecular phylogeny of the genus, using mitochondrial cytochrome b sequences from 137 individuals across their range and a ddRADseq genomic analysis on 34 individuals. The phylogenetic results revealed three main clades: (1) Guiana Shield sakis, (2) Sedimentary Basin and Brazilian Shield sakis, and (3) a basal P. albicans south of the Rio Solimoes. The ddRADseq data further clarified species boundaries and relationships, identifying six distinct species: P. chrysocephala and P. pithecia sensu Hershkovitz (1987) on the Guiana Shield; P. albicans in central Amazonia south of the Rio Solimoes; P. monachus in western Amazonia; P. irrorata between the rios Purus, Tapajos, and Juruena; and P. vanzolinii in a limited area east of the Rio Jurua.

zoology↗

bioRxiv2023

Seasonal fluctuations in the bone microstructure of Sciurus vulgaris fuscoater humeri: a case study using phenomics on μCT-scans

Sciurus vulgaris Linnaeus, 1758, the red squirrel, is a small, mostly arboreally living rodent, spread across the Palearctic. It is mostly vegetarian, feeding on plants, fungi and seeds, and is less active in the winter months, but does not hibernate. In this lateral study, the humeri of the subspecies Sciurus vulgaris fuscoater, the Central European red squirrel, were analysed to uncover potential intraspecific variation between individuals found in different seasons. The {micro}CT-scans were obtained with a resolution of 26 microns. Five bone parameters were calculated and statistically evaluated with regards to seasonal variations: total volume, bone volume, endocortical surface, cortical thickness, and average trabecular thickness. Bone volume, trabecular thickness and endocortical thickness correlate with bone size, whereas cortical thickness does not. Seasonal differences were observed between the warmer summer and autumn months versus the colder winter and spring months for all parameters. We, speculatively, relate the observed seasonal variation to nutrient intake, notably calcium. These results offer a deeper understanding of intraindividual variation in red squirrels, that may be useful in further ecological, taxonomic, and paleontological research.

zoology↗

bioRxiv2023

Cementochronology using synchrotron radiation tomography to determine age at death and developmental rate in the holotype of Homo luzonensis

Homo luzonensis, a fossil hominin from the Philippines, is smaller than modern humans. At present, very little is known about the life history of this species. Cementochronology can answer life history questions, but usually involves destructive sampling. Here, we use synchrotron radiation to count the yearly cement lines of teeth belonging to a single individual. This approach allows us to determine that this individual was likely 31 years old at time of death and apparently had a developmental pattern comparable to chimpanzees. To our knowledge, this is the first time that cementochronology using synchrotron radiation tomography is used for life history and age-at-death estimation.

paleontology↗