Leif Moritz

Many animals can sense the Earth’s magnetic field and use it for orientation. However, the mechanism underlying magnetoreception has not been identified, partially due to the lack of reproducible and genetically tractable model systems. Here, we establish a directional assay for planaria to test their responses to different magnetic fields. Girardia dorotocephala showed a preferred magnetic directionality in the horizontal plane in an Earth-strength magnetic field in the absence of visible light, which shifted if the azimuth was rotated and was absent when the magnetic field was cancelled. This directional preference differed between labs. Furthermore, the directional response was affected by a short but strong magnetic pulse, resulting in a random distribution. The effect of the pulse was temporary, with directional preferences recovering over several days. Taken together, these data are consistent with a magnetoreception mechanism in planarians that functions independently of light and relies on permanently magnetised material, such as single-domain magnetite. As planarians are genetically tractable and well-established, they are a promising invertebrate model organism that might offer insights into the mechanisms underlying magnetoreception in animals.

Catastrophic events like climatic changes can lead to a drastic decline and loss of populations in widespread species. Small refugia can shield relict populations from extinction and are of great importance for maintaining genetic diversity and for recolonization events. In the giant centipede Scolopendra cingulata Latreille, 1829, widely distributed along the Mediterranean Sea, the northern-most populations occur in isolated microrefugia in Austria and Hungary. The origin and relationships of these populations remain largely unknown. Here we describe a second, previously unknown, microrefugial population of S. cingulata from Austria and provide insights into the evolutionary history of the northern-most populations of the species based on molecular analyses (COI) of 16 populations. Our results show that the Austrian and Croatian populations are closely related, while genetically distinct from the Hungarian and Romanian representatives. Therefore, we conclude that the northern-most populations of S. cingulata are relicts from multiple independent post-glacial recolonization events from southern refugia.

Magnetoreception, the ability to perceive the geomagnetic field, is widespread across animals. The underlying sensory mechanism remains elusive, but a long-standing hypothesis proposes single-domain magnetite linked to mechanosensitive ion channels. The Ansell's mole-rat ( Fukomys anselli ) is a subterranean rodent with a magnetic sense, and published behavioral and histological data are consistent with magnetite-based magnetoreceptors in the cornea or retina. Here, we systematically screened for magnetite in the mole-rat eye, combining iron detection via enhanced Prussian blue staining and synchrotron X-ray fluorescence microscopy (XFM) with magnetic detection via MRI quantitative susceptibility mapping (MRI-QSM) and quantum-diamond microscopy (QDM). This revealed only a few iron particles in the retina and cornea, which predominantly overlapped with titanium or chromium, indicating a non-biogenic origin. XFM showed iron-enriched lines in the cornea, but these did not show ferrimagnetic signals. Focusing on other ocular tissues, MRI-QSM revealed the highest susceptibility in the ciliary body, where iron-rich pigmented cells were identified. A TEM-screen, however, failed to detect single-domain magnetite particles in these cells. We conclude that our high-sensitivity multimodal screen provides no evidence for magnetite-based magnetoreceptors in the mole-rat eye, suggesting that mole-rat magnetoreceptors either do not reside in the eye or are based on different physical principles.

Mole-rats are subterranean rodents that have evolved remarkable sensory adaptations to life in underground tunnel systems, yet their neural mechanisms remain largely unexplored. Here, we present a protocol for in vivo electrophysiological recordings in awake, head-fixed, and freely moving African mole-rats ( Fukomys anselli/micklemi ), overcoming unique challenges of studying the neurobiology of subterranean species. We find that mole-rat brain physiology impacts survival after surgeries, with higher carbon dioxide concentrations required for recovery compared to other rodents, likely due to a mutation in the chloride-potassium symporter KCC2. Having addressed these challenges through our optimized methodology, we used tetrodes and Neuropixels probes to record single-unit activity and local field potentials (LFP) across several cortical and subcortical regions for several weeks. We observed single units responsive to auditory and visual stimuli in the superior colliculus, and hippocampal recordings in freely moving mole-rats revealed prominent theta rhythms at frequencies lower than those observed in any other rodent species to date. Finally, we performed integrated three-dimensional and two-dimensional probe-track analysis within the same brain using tissue clearing, light sheet imaging, rehydration, and vibratome sectioning, and we present a newly developed stereotaxic brain atlas for implantation and histological alignment. This established methodology will guide future studies in comparative rodent neurobiology, providing further insights into neurobiological adaptations to subterranean environments. Given their phylogenetic and ecological similarities, we expect our protocols to be transferable to other subterranean species, including the widely studied naked mole-rat ( Heterocephalus glaber ).

Millipedes (Diplopoda) are an abundant group of fossilized terrestrial arthropods throughout the Palaeozoic Era. However, there is a gap in the Mesozoic Period with only slightly more than a dozen fossils known, until more recent fossil records – mainly from Cenozoic Dominican and Baltic ambers – became available. Here, we describe a millipede of the family Siphonorhinidae from Myanmar amber, a species-poor group, comprising just six extant genera, disjunctly distributed in Southeast Asia, South Africa, Madagascar, Chile and California. Micro-computed tomography (µ-CT) enabled detailed visualizations of essential elements for description, including the tergites, legs, head, antenna, and notably the gonopods. The new genus shares some characteristics with species of the extant genus Siphonorhinus Pocock, 1894. Protosiphonorhinus patrickmuellerigen. et sp. nov. differs from extant species of the family mainly in the shape of the antenna, tergites, and anterior gonopods. A recently described fossil species of Siphonophorida from Myanmar amber was erroneously assigned to the family Siphonorhinidae. We transfer it to the family Siphonophoridae, as Siphonophora globosa (Su, Cai & Huang, 2024) comb. nov. The description of the new genus and the reinterpretation of the previously described fossil Siphonorhinidae allows for a rejection of a hypothesis of bradytely within the Siphonorhinidae from the mid-Cretaceous to the present day.

Die Westghats Indiens sind weltweit einer der bedeutendsten Hotspots der Biodiversität. So wurden ungefähr 60% aller aus Indien bekannten Doppelfüßer (Diplopoda; > 270 Arten) während der Kolonialzeit aus dieser Region beschrieben. Bisher waren insgesamt lediglich sechs Arten aus zwei Ordnungen in der Subterklasse Colobognatha aus Indien bekannt: Die Ordnung Polyzoniida mit drei Arten in der Familie Siphonotidae Cook, 1895 aus den Westghats (Südindien) sowie die Ordnung Siphonophorida mit drei Arten in der Familie Siphonorhinidae Cook, 1895 aus dem Himalaya (Nordindien). Basierend auf Rastereletronenmikroskopie (REM), micro-CT, Lichtmikroskopie und CO1-Barcoding beschreiben wir mit morphologischen und molekularen Daten eine weitere Art, Siphonorhinus parambikulam sp. n. (Siphonophorida: Siphonorhinidae) aus dem Parambikulam Tiger Reservat der südlichen Westghats in Kerala (Indien). Siphonorhinus parambikulam sp. n. unterscheidet sich von den acht anderen Arten der Gattung durch Unterschiede in der Anzahl der Tergite, Körperlänge und -breite, Färbung, Anzahl der anterioren und posterioren Gonopodenglieder und in der Form der apikalen Podomere der anterioren und posterioren Gonopoden. Darüber hinaus beschreiben wir das erste Männchen der Gattung Siphonorhinus Pocock, 1894 aus Indien. Die verfügbare Anzahl an CO1-Sequenzen der Siphonophorida wurde von drei auf insgesamt 56 erweitert und beinhaltet nun neue Sequenzen von 33 Individuen aus Indien, 16 aus Java (Indonesien) und vier aus Neuseeland. Diese Daten lieferten die Grundlage für die bisher umfassendste molekulare Analyse der Ordnung Siphonophorida. Ebenso legen wir die ersten Nachweise sowie CO1-Sequenzen der Familie Siphonophoridae aus Indien vor, die auf eine hohe, bisher unbeschriebene Diversität in den indischen Westghats hindeuten. Diese Studie weist darauf hin, dass die Doppelfüßer der indischen Westghats nicht ausreichend besammelt sind und die Region ein Biodiversitätshotspot der nur unzureichend erforschten Colobognatha darstellen könnte.

The millipede family Siphonorhinidae (order Siphonophorida) shows a scattered distribution in South Africa, Madagascar, India, Southeast Asia, and North America. So far, the family is unknown from South America, while species of Siphonophoridae, the second family of the order, are relatively abundant on the continent. However, not a single Siphonophorida is known from Chile. Here we describe the monotypic genus Notorhinusgen. nov. with N. floresisp. nov. and record a second Notorhinus (undescribed) species, as first records of the order Siphonophorida in Chile and of the family Siphonorhinidae in South America. Notorhinusgen. nov. is distinct from the remaining Siphonorhinidae by the arrangement of the sensilla basiconica on the antennae and other somatic and sexual characters. However, it shows close morphological affinities to the North American genus IllacmeCook and Loomis 1928. In the Americas Siphonorhinidae were previously only known from California (USA), where they inhabit subterranean micro-habitats. The Chilean species was found under a piece of decaying wood in a small patch of fragmented native forest. Thus, the group shows a disjunct antitropical distribution in America at ca. 37° North and 38° South. They might be the relict of a once greater distribution, which persisted in these areas due to similar climatic conditions.