Onychophorology, the study of velvet worms, historical trends, landmarks, and researchers from 1826 to 2020 (a literature review)

Abstract

Velvet worms, also known as peripatus or onychophorans, are a phylum of evolutionary importance that has survived all mass extinctions since the Cambrian period. They capture prey with an adhesive net that is formed in a fraction of a second. The first naturalist to formally describe them was Lansdown Guilding (1797-1831), a British priest from the Caribbean island of Saint Vincent. His life is as little known as the history of the field he initiated, Onychophorology. This is the first general history of Onychophorology, which has been divided into half-century periods. The beginning, 1826-1879, was characterized by studies from former students of famous naturalists like Cuvier and von Baer. This generation included Milne-Edwards and Blanchard, and studies were done mostly in France, Britain, and Germany. In the 1880-1929 period, research was concentrated on anatomy, behavior, biogeography, and ecology; and it is in this period when Bouvier published his mammoth monograph. The next half-century, 1930-1979, was important for the discovery of Cambrian species; Vachon’s explanation of how ancient distribution defined the existence of two families; DNA and electron microscopy from Brazil; and primitive attempts at systematics using embryology or isolated anatomical characteristics. Finally, the 1980-2020 period, with research centered in Australia, Brazil, Costa Rica, and Germany, is marked by an evolutionary approach: from body and behavior to geographic distribution; the discovery of how they form their adhesive net; the reconstruction of Cambrian onychophoran communities, the first experimental taphonomy; the first country-wide map of conservation status (in Costa Rica); the first model of why they survive in cities; the discovery of new phenomena like food hiding, parental feeding investment, and ontogenetic diet shift; and the birth of a new research branch, onychophoran ethnobiology. While a few names often appear in the literature, most knowledge was produced by a mass of researchers who entered the field only briefly.

Two Centuries of Velvet Worm Research: A Brief Illustrated History of Onychophorology

“…The study of onychophorans, often called "peripatus" or velvet worms, offers a fascinating field from biology to folklore. Originating over 500 million years ago, during the Cambrian period, they are important in the fields of evolution, physiology, behavior and, more recently, biologically-based adhesives (Cerullo et al, 2020;Monge-Nájera, 2020).…”

“…Secondly, their physiological and behavioral adaptations distinguish them from other invertebrate taxa. Their velvety appearance is the result of a flexible skin with papillae and sensory bristles that allow them to feel their way in the subterranean ecosystems they occupy the world over (Monge-Nájera, 2020).…”

Encapsulated salts in velvet worm slime drive its hardening

“…in 3D bioprinting of biomacromolecules applications 2 , 3 . In this view, the unique slime secretion used by velvet worms—invertebrates from the phylum Onychophora—for defense, prey capture and parental feeding 4 , 5 is exemplary. The velvet worm Epiperipatus biolleyi, which is found in Central America 6 , produces a white sticky slime that strongly adheres to a wide variety of materials such as wood, metals, glass, and biological tissues.…”