Dermal papillae (Onychophora)

Last updated
Dermal papillae on the peripatopsid velvet worm Ooperipatellus viridimaculatus Ooperipatellus viridimaculatus 34495491.jpg
Dermal papillae on the peripatopsid velvet worm Ooperipatellus viridimaculatus

Dermal papillae are small protrusions on the cuticle of onychophorans, a group of animals commonly known as velvet worms. These structures give the group their common name, as they have a velvet-like feel when touched. [1] Dermal papillae come multiple forms and cover the body of onychophorans in rings known as annulations. [2]

Contents

Development

Types

Primary papillae

Talk about structure and make a diagram showing differences between Peripatidae and Peripatopsidae primary papillae [2]

Type 1 sensilla

Type 1 sensilla are a specialized variant of primary papilla with a prominent apical piece covered in scales and a sensory bristle with a textured base. These papillae act as mechanoreceptors, giving the animals a sense of touch, and occur in peripatid velvet worms. [2]

Type 2 sensilla

Type 1 sensilla are similar to type 1 sensilla but lack an apical piece and have a far longer bristle. [2]

Spindle-shaped sensilla

Spindle-shaped sensilla are a modified version of Type 1 sensilla that have a large, spindle-shaped apical piece and a short, thorn-like bristle. Like regular type 1 sensilla, these also only occur in peripatid velvet worms. In life, spindle-shaped sensilla make up an array known as the antennal sensory field. This is located on the underside of the antennae on its proximal (closer to the base) portion. [2]

Accessory papillae

Crater shaped papillae

Pigmentation

References

  1. 1 2 Schierwater, B.; DeSalle, Rob (2021). Invertebrate zoology: a tree of life approach. Boca Raton: Taylor & Francis. p. 461. ISBN   978-1-4822-3581-4.
  2. 1 2 3 4 5 6 Oliveira, Ivo de Sena; Franke, Franziska Anni; Hering, Lars; Schaffer, Stefan; Rowell, David M.; Weck-Heimann, Andreas; Monge-Nájera, Julián; Morera-Brenes, Bernal; Mayer, Georg (2012-12-17). "Unexplored Character Diversity in Onychophora (Velvet Worms): A Comparative Study of Three Peripatid Species". PLOS ONE. 7 (12): e51220. Bibcode:2012PLoSO...751220O. doi: 10.1371/journal.pone.0051220 . ISSN   1932-6203. PMC   3524137 . PMID   23284667.