Dataset on Exoskeleton Chemistry and Surface Morphology of the pill millipede, Arthrosphaera lutescens.

NMR Data: This dataset contains raw and processed solid-state Nuclear Magnetic Resonance (NMR) spectroscopy data acquired from pill bug exoskeleton samples for structural and compositional analysis. ¹³C and ³¹P cross-polarization magic angle spinning (CP-MAS) NMR spectra were recorded using a 500 MHz NMR spectrometer equipped with a 4 mm broadband MAS probe. Samples were spun at a magic angle spinning (MAS) frequency of 10 kHz. SPINAL64 ¹H decoupling was employed during acquisition to suppress heteronuclear dipolar interactions between ¹H and ¹³C/³¹P nuclei, enabling improved spectral resolution. The repository includes raw files as well as processed spectra obtained following standard Fourier transformation, phase correction, and baseline correction procedures.AFM Data: Atomic Force Microscopy (AFM) data were generated to examine the microstructural features of the exoskeleton of Arthrosphaera lutescens. Measurements were performed using an NTEGRA scanning probe microscope (NT-MDT Spectrum Instruments) in tapping mode under ambient air conditions to minimise surface damage and tip–sample interaction artefacts. Exoskeletal samples were dissected from the seventh dorsal tergite, and a smooth, flat region from the middle portion was selected; specimens were cut into approximately 1 × 1 cm pieces and mounted using double-sided adhesive tape. Imaging was conducted using a silicon nitride (Si₃N₄) cantilever with a gold-coated reflective backside (nominal resonant frequency 235 kHz, spring constant 12.0 N m⁻¹), at a scan resolution of 256 × 256 pixels and a feedback gain of 0.01. Raw AFM scan files and processed two- and three-dimensional topographical images are provided, and quantitative surface morphology and roughness parameters were extracted using NT-MDT NOVA image analysis software to ensure reproducibility and data reuse.Fluorescence and ultraviolet (UV) microscopy data were obtained to analyse the autofluorescence properties of the exoskeleton of the millipede Arthrosphaera lutescens. Exoskeletal samples from the median region of the seventh tergite were excised and sectioned into approximately 5 mm pieces for imaging. Observations were carried out using a Zeiss Axio Stereo microscope under autofluorescence and UV excitation conditions. Images were recorded at different magnifications employing standard fluorescence filter sets, including DAPI, FITC, and Cy3. Both raw and processed fluorescence images are provided to facilitate reproducibility and data reuse.FTIR Data: Fourier Transform Infrared (FTIR) spectroscopy data were generated to characterise the chemical composition of the exoskeleton of Arthrosphaera lutescens. Exoskeletal shells were washed, dried, and pulverised into a fine powder, followed by sequential cleaning to remove impurities. The shell material was treated with 2% NaOH under controlled heating to remove proteins, washed thoroughly with deionised water, and subsequently decalcified using 1 N HCl (7%) until cessation of gas evolution. The processed material was filtered, washed, oven-dried, and subjected to FTIR analysis using a PerkinElmer FTIR spectrometer. Raw and processed infrared spectra are providedHistology analysis: Histological data were obtained to evaluate connective tissue components of the exoskeleton using Mallory’s Trichrome staining. Sections were deparaffinised, rehydrated, stained with 0.5% acid fuchsin for 7 minutes, followed by aniline blue–orange for 15 minutes, and rinsed to remove excess stain. The slides were dehydrated through 95% ethanol, cleared, and mounted for microscopic examination. Processed histological images are provided.ICP- MS: Inductively Coupled Plasma–Mass Spectrometry (ICP–MS) data were generated to determine the elemental composition of the exoskeleton of Arthrosphaera lutescens. Approximately 50 mg of dried exoskeleton material was digested with nitric acid (HNO₃) following the addition of double-distilled water and heating at temperatures not exceeding 120 °C. After cooling, hydrogen peroxide (H₂O₂) was added to ensure complete oxidation of residual organic matter, followed by brief heating and cooling. The digested sample was diluted to a final volume of 10 mL, with a subsequent 1:10 dilution to obtain the working solution. The final solution was filtered and analysed using an Agilent 7800 ICP–MS instrument. Raw and processed elemental data are provided to support reproducibility and data reuse.Nanoindentation experiments were performed to assess the mechanical properties of the exoskeleton of Arthrosphaera lutescens. Exoskeleton samples were collected from the mid-body tergites (segments 6–7), avoiding regions subjected to prior mechanical manipulation. Small sections (~3 mm) from the middle portion were carefully excised using a razor blade and mounted onto a sample holder to minimise structural damage. Indentation measurements were carried out using a Hysitron Bruker TI Premier nanoindenter with a maximum load of 1000 µN. Parameters including indentation depth, strain rate, harmonic displacement, and harmonic frequency were recorded using TriboScan 9 software.XRD data: X-ray diffraction (XRD) data were obtained to examine the crystalline characteristics of the exoskeleton of Arthrosphaera lutescens. Exoskeletal material was dried and finely powdered prior to analysis. XRD patterns were recorded at room temperature using a PANalytical X’Pert³ Powder X-ray diffractometer equipped with Cu Kα radiation (λ = 1.5406 Å). The instrument was operated at an accelerating voltage of 40 kV and a tube current of 40 mA.SEM EDAX data: Scanning Electron Microscopy coupled with Energy Dispersive X-ray Analysis (SEM–EDAX/EDS) was employed to examine the surface morphology and elemental composition of the exoskeleton of Arthrosphaera lutescens. SEM imaging was used to document surface microstructural features, and EDAX analysis was conducted for elemental characterisation. The elemental composition was determined using standard ZAF-based quantitative analysis, and the detected elements included carbon (C), oxygen (O), magnesium (Mg), phosphorus (P), sulfur (S), and calcium (Ca). Raw SEM micrographs, EDAX spectra, and processed elemental composition data are provided as part of this dataset.SEM data: Scanning Electron Microscopy (SEM) images were acquired to examine the surface morphology and microstructural features of the exoskeleton of the pill bug Arthrosphaera lutescens. SEM imaging was performed using the same microscope and operating conditions as those employed for EDAX analysis, enabling direct correlation between surface structure and elemental composition. Exoskeletal samples were prepared for electron microscopy and imaged at multiple magnifications to document surface topography and structural organisation.Hydrophobicity analysis: Surface hydrophobicity of the exoskeleton of Arthrosphaera lutescens was evaluated using water contact angle measurements. A live specimen was positioned on a glass slide, and a small droplet of water was carefully deposited onto the exoskeletal surface using a fine injection needle. The slide was placed on the sample holder of a KYOWA DMs-401 contact angle measurement system, and droplet images were captured using a high-resolution camera attached to the instrument. Contact angles were subsequently determined from the recorded images to assess the wetting behaviour of the exoskeleton surface.Confocal Raman analysis: Confocal Raman spectroscopy and imaging were performed to examine the biochemical composition and structural bonding characteristics of the exoskeleton of the pill bug Arthrosphaera lutescens. Analyses were conducted on naturally pigmented black, yellow, and green regions located on the dorsal surface of the seventh tergite using a WITec Alpha 300R confocal Raman microscope. A small exoskeletal fragment (~3 mm) containing the coloured regions was carefully excised from the mid-body tergite, gently cleaned to remove surface debris while preserving structural integrity, and mounted for analysis. Confocal Raman spectra and spatially resolved Raman images obtained from different pigmentation regions are provided as part of this dataset.The exoskeleton of A. lutescens was washed, dried, and powdered, purified repeatedly with distilled water, treated with 2% NaOH at 60–70 °C and incubated overnight, followed by demineralization using 7% of 1 N HCl until effervescence ceased, then washed and oven-dried at 60 °C, after which the purified shell powder was analyzed using Fourier Transform Infrared (FTIR) spectroscopy to determine its functional groups and chemical composition.