Ultrastructure of trichome of old world porcupine of Indian subcontinent

The present investigation is based on ultrastructural details of different types of quills of two species of old world porcupine (Hystrix indica and Hystrix brachyura) of Indian subcontinent using environmental scanning electron microscopy (ESEM). In H. indica, four types of quills have been detected – bristlelike spines, stilettolike spines, spikes and mane. The quills of H. brachyura are categorized into four types – broad, slender, hollow tail quill and quills of the anogenital region. The ESEM images of surface characteristic of different types of quills of both the species except the hollow tail quill showed usual scaly features without having any differences. The cross‐sectional images of quills of H. indica and H. brachyura show a narrow cortex and a broad medullary region with a network of anastomosing channels. The cortical layer is comparatively thicker in mane hairs of H. indica and in slender quills of H. brachyura. With extensive exploration of the anatomical structures of the quills by ESEM from both the species of Hystrix, we could not find ‘osmetrichia’ in any forms of quill. In contrast, we hypothesized that the channels and network of medulla are serving the purpose for transportation of pheromonal signalling molecules in old world porcupine.