Patrick Arnold

Universität Potsdam · Institute of Biochemistry and Biology

The Ruwenzori otter shrew (Micropotamogale ruwenzorii) is one of the three otter shrew species left and the relic of an ancient pan-African distribution of insectivoran-grade afrotherians that survived on continental Africa. Like the other two otter shrews, this species exhibits a semi-aquatic ecology and morphology similar to otters, water shrews...

Sengis (Macroscelidea) are members of the Afroinsectivora, a group of mammals belonging to the supercohort Afrotheria. Sengis’ low population densities and their distribution, which includes politically unstable regions with ongoing armed conflicts, hinder contemporary sampling of comprehensive datasets. We overcome this obstacle for the species Pe...

The typical mammalian neck consisting of seven cervical vertebrae (C1–C7) was established by the Late Permian in the cynodont forerunners of modern mammals. This structure is precisely adapted to facilitate movements of the head during feeding, locomotion, predator evasion, and social interactions. Eutheria, the clade including crown placentals, ha...

Besides manatees, the suspensory extant 'tree sloths' are the only mammals that deviate from a cervical count (CC) of seven vertebrae. They do so in opposite directions in the two living genera (increased versus decreased CC). Aberrant CCs seemingly reflect neck mobility in both genera, suggesting adaptive significance for their head position durin...

We undertook a phylogenetic analysis of genetic and anatomical data focusing on golden moles (Chrysochloridae) and tenrecs (Tenrecidae). Our results support the now well-resolved topology for extant tenrecids, in addition to the paraphyly of ‘Chrysochlorinae’ and the genera Chrysochloris and Chlorotalpa as traditionally used. Carpitalpa arendsi is...

Sengis or elephant shrews (Macroscelidea) are small African mammals, with most species inhabiting arid regions. The four-toed sengi (Petrodromus tetradactylus), however, roams diverse habitats from coastal and Afromontane forest, to Zambezian woodlands and savannahs, to Congolian lowland forest. It has one of the largest geographic ranges of all se...

In his extensive travel reports from Mozambique (Naturwissenschaftliche Reise nach Mossambique, auf Befehl seiner Majestät des Königs Friedrich Wilhelm IV. in den Jahren 1842 bis 1848 ausgeführt), the German naturalist Wilhelm Peters collected and examined several specimens of sengis from south-east Africa. He first described the species Macrosceli...

Sengis (order Macroscelidea) are small mammals endemic to Africa. The taxonomy and phylogeny of sengis has been difficult to resolve due to a lack of clear morphological apomorphies. Molecular phylogenies have already significantly revised sengi systematics, but until now no molecular phylogeny has included all 20 extant species. In addition, the a...

Afrotheria are one of the four major clades of placental mammals that have been defined based on molecular data. It unites morphologically diverse lineages with a common ancient origin in Africa: elephants, sea cows, hyraxes, aardvarks, sengis, golden moles and tenrecs. Under the current systematic consensus, afrotherians are divided into an ungula...

African otter shrews (Potamogalidae) are Afrotherian mammals adapted to a semi-aquatic lifestyle. Given their rareness, genetic data on otter shrews are limited. By applying laboratory methods tuned for the recovery of archival DNA and an iterative mapping approach, we reconstructed whole mitochondrial genomes of the Giant (Potamogale velox) and Ru...

Macroscelidea or sengis are small mammals endemic to Africa and consists of 20 extant species only. Together with aardvarks, hyraxes, elephants, sea cows and afrosoricidans, they form the Afrotheria, the major clade of placental mammals with ancient African origin. Due to mostly cryptic morphological traits, biologist had a hard time disentangling...

Malagasy shrew tenrecs (Microgale) have increasingly been used to study speciation genetics over the last years. A previous study recently uncovered gene flow between the Shrew-toothed shrew tenrec (M. soricoides) and sympatric southern population of the Pale shrew tenrec (M. fotsifotsy). This gene flow has been suggested to be accompanied by compl...

Sengis are small African mammals with an odd character combination and a long independent evolution. They have traditionally been divided into four morphologically well-defined genera: Macroscelides, Petrodromus, and Elephantulus (Macroscelidinae, soft-furred sengis) as well as Rhynchocyon (Rhynchocyoninae, giant sengis). Molecular analyses, howeve...

Zalambdalestidae are a group of Late Cretaceous eutherians endemic to Asia. Most Zalambdalestids are known from teeth and fragmentary mandibular/maxillary remains, but Zalambdalestes is represented by some nearly complete skeletons. Specifically, the postcranial remains of Zalambdalestes, which we analyzed with microcomputed tomography, include an...

The mammalian neck adopts a variety of postures during daily life and generates numerous head trajectories. Despite its functional diversity, the neck is constrained to seven cervical vertebrae in (almost) all mammals. Given this low number, an unexpectedly high degree of modularity of the mammalian neck has more recently been uncovered. This work...

In mammals, the number of vertebrae and the somites they derive from is highly limited. Nevertheless, there are some lineages that have an increased number of presacral vertebrae and thus an elongated trunk. This suggests that somitogenesis, the process of somite formation in early development, is altered in these lineages. According the ‘clock and...

Afrotherian Conservation Sengis or elephant shrews are small-sized afrotherians that combine traits of insectivores, rodents, and ungulates. They have a checkered taxonomic and scientific history which is here briefly traced by means of historical illustrations.

Despite its functional diversity, the neck is constrained to seven cervical vertebrae in almost all mammals, making it a gripping subject for evolutionary biologists. Research in this specific field is generally focused on the developmental and evolutionary origin of the fixed number of cervical vertebrae. However, less attention is given on how hi...

Sciuromorph rodents are a monophyletic group comprising ~300 species that display a variety of locomotor behaviours and a body mass range spanning three orders of magnitude. We asked how the interaction of body mass and locomotor ecology affects the morphology of the scapula. Univariate traits and the shape of the scapula from the lateral view of 1...

Sciuromorph rodents are a monophyletic group comprising ~300 species that display a variety of locomotor behaviours and a body mass range spanning three orders of magnitude. We asked how the interaction of body mass and locomotor ecology affects the morphology of the scapula. Univariate traits and the shape of the scapula from the lateral view of 1...

Sciuromorph rodents are a monophyletic group comprising about 300 species with a body mass range spanning three orders of magnitude and various locomotor behaviors that we categorized into arboreal, fossorial and aerial. The purpose of this study was to investigate how the interplay of locomotor ecology and body mass affects the morphology of the s...

Reconstructing the locomotion of extinct vertebrates offers insights into their palaeobiology and helps to conceptualize major transitions in vertebrate evolution1–4. However, estimating the locomotor behaviour of a fossil species remains a challenge because of the limited information preserved and the lack of a direct correspondence between form a...

Background: Sloths are one of only two exceptions to the mammalian 'rule of seven' vertebrae in the neck. As a striking case of breaking the evolutionary constraint, the explanation for the exceptional number of cervical vertebrae in sloths is still under debate. Two diverging hypotheses, both ultimately linked to the low metabolic rate of sloths,...

Background Sciuromorpha (squirrels and close relatives) are diverse in terms of body size and locomotor behavior. Individual species are specialized to perform climbing, gliding or digging behavior, the latter being the result of multiple independent evolutionary acquisitions. Each lifestyle involves characteristic loading patterns acting on the bo...

Background The increase in locomotor and metabolic performance during mammalian evolution was accompanied by the limitation of the number of cervical vertebrae to only seven. In turn, nuchal muscles underwent a reorganization while forelimb muscles expanded into the neck region. As variation in the cervical spine is low, the variation in the arrang...

Background Bone structure has a crucial role in the functional adaptations that allow vertebrates to conduct their diverse lifestyles. Much has been documented regarding the diaphyseal structure of long bones of tetrapods. However, the architecture of trabecular bone, which is for instance found within the epiphyses of long bones, and which has bee...

Almost all mammals have seven vertebrae in their cervical spines. This consistency represents one of the most prominent examples of morphological stasis in vertebrae evolution. Hence, the requirements associated with evolutionary modifications of neck length have to be met with a fixed number of vertebrae. It has not been clear whether body size in...

The neck skeleton is constituted as a highly mobile, multi-element and multi-joint kinematic chain. This construction leads to a kinematic redundancy on several levels. The problem of coordinating a large number of joints and muscles is solved by reducing the degrees of freedom to only few preferred motor axes. This is achieved by the regionalizati...

The fore and hind limbs as a mammal’s major motion system underlie distinct developmental and functional patterns constraining limb construction to a small number of general traits. The neck skeleton, a highly movable, open kinematic chain, also represents an important motion system as it actuates the head trajectories during all daily life activit...

Despite the constraint number of cervical vertebrae, former studies suppose a functional tripartite regionalisation of the mammalian neck skeleton similar to that of other amniotes. In contrast, anatomists usually divide the cervical spine (CS) only into two morphological units: the upper CS (Atlas and Axis) and the lower CS (C3-C7). Although some...

The reconstruction of a joint's maximum range of mobility (ROM) often is a first step when trying to understand the locomotion of fossil tetrapods. But previous studies suggest that the ROM of a joint is restricted by soft tissues surrounding the joint. To expand the limited informative value of ROM studies for the reconstruction of a fossil specie...