Present state of systematics in ONYCHOPHORA
The phylum Onychophora is composed of two families : Peripatidae
and Peripatopsidae.
The Peripatopsidae are under revision by C. Brockman, D. Gleeson,
A. Reid and H. Ruhberg.
To see the complete group, go to the CHECKLIST.
Some Selected Main references
Hamer, M.L., Samways, M.J. & Ruhberg, H. (1997). A review of the Onychophora of South Africa, with discussion of their conservation. Annals of the Natal Museum, 38: 283-312.
Gleeson, D.M. (1996). Onychophora of New Zealand; past, present and future. New Zealand Entomologist, 19: 51-55.
Peck, S.B. (1975). A review of the New World Onychophora species and genus from Jamaica. Psyche, 82 (3-4): 341-358.
Read, V.M.St.J. (1988). The application of scanning electron microscopy to the systematics of the neotropical Peripatidae (Onychophora). Zoological Journal of the Linnean Society, 93: 187-223.
Reid A.L. (1996). Review of the Peripatopsodae (Onychophora) in Australia, with comments on peripatopsid relationships. Invertebrate Taxonomy, 10(4): 663-936.
Ruhberg, H. (1985). Die Peripatopsidae (Onychophora). Systematik, Ökologie, Chorologie und phylogenetische Aspekte. Zoologica, 137: 1-184.
and recent works by C. Brockmann, A. Reid, H. Ruhberg, N. Tait........
where are they ? / où sont les onychophores ?
who are onyphorologists ? / qui sont les onychophorologistes ?
where are they ? / où sont-ils ?
and see general informations by Julian MONGE-NAJERA, Lynn MARGULIS and coll. in ONYCHOPHORA NEWSLETTER : http://www.ots.ac.cr
Onychophora Online© is a source of information on onychophorans (also known as velvet worms; the name "peripatus" is not recommended because it favors confusion with the taxonomic genus Peripatus).
Onychophorans are "living fossils" in the sense that
they have changed little in their body shape for about 500 million
years.
Probably they were the first animals ever to walk, according to
a phylogeny (a sort of family tree) constructed by a technique
called cladistics.
Fossils indicate that they lived in shallow marine environments
in the Cambrian, in tropical habitats from many parts of the world.
The first onychophorans often had long "legs", spines,
head shields and body plates thought to have played a defensive
role. They probably hunted smaller animals for food.
With time, they colonized dry land and those that may have remained
in the sea became extinct. Terrestrial species have short locomotory
appendages, pseudo-legs called lobopods or oncopods, lack spines
and armouring, and hunt their prey with the help of an adhesive
that is expelled in liquid form from head organs (this includes
specimens preserved in ambar). Apparently, onychophorans evolved
from polychaete worms and have intermediate characteristics between
annelids and arthropods, which results in periodical proposals
for incorporating them into any of these two groups, depending
on the characters that the proponents happen to chose (for example,
biochemical traits).
Onychophorans are found un moist, dark places like rotten logs,
leaf litter and soil crevices and normally become active at night,
when the danger of dessication is less. The family Peripatopsidae
is found in Chile, South Africa, Australia and adjacent islands,
some members are oviparous, others ovoviviparous. The family Peripatidae
is found in tropical parts of Latin America, Africa and Asia;
it has viviparous species: females bear live offspring that develop
in association with a placenta, an extraordinary characteristic
for a tiny worm labeled as "living fossil".
These velvet-worms can reach 20 cm in length (although most are
less than 5 cm long, and males are smaller in all species) and
often are brown, but can also be red, blue or golden.
Although textbooks tend to present much "general" information
about onychophorans, the truth is that we know close to nothing
about the great majority of the about 200 species. Onychophorans
are exceedingly rare and probably endangered in many habitats.
Mike Grieneisen has started an "Onychohoran Homepage" to provide links to the major on-line resources wich contains informations about onychophorans. We should together be able to build a truly thorough and accurate bibliography on the onychophorans.
It is posted at : http://www.sciref.org/onychophora/index.htm
see onychophora@yahoogroups.com
It has been updated with references up through 2001 and posted at http://www.sciref.org/onychophora/biblio.htm. The author Index, which facilitates finding all references authored by any individual is posted at : http://wwwsciref.org/onychophora/authors.htm. It has been also posted ".rtf" versions of these files which allow you to make printed copiues using just about any word processing programm: www.sciref.org/onychophora/biblio20.rtf and www.sciref.org/onychophora/auths20.rtf