The Peripatidae or Equatorial velvet worms are a family of velvet worms. This family includes more than 90 described species distributed among 13 genera, but some authorities deem only 80 of these species to be valid. The oldest putative representatives of the family herald from Burmese amber dated to the mid-Cretaceous, around 100 million years ago, with representatives from Dominican and Baltic amber attesting to a broader distribution in the Palaeogene / Neogene; molecular variability suggests that the family's crown group may have arisen in the early Mesozoic.
Description The Peripatidae exhibit a range of derivative features. They are longer, on average, than the Peripatopsidae and also have more leg pairs. The number of legs in the Peripatidae varies within species as well as among species and ranges from 19 pairs (in Typhloperipatus williamsoni and Speleoperipatus spelaeus) to 43 pairs (in Plicatoperipatus jamaicensis). The gonopore is always between the penultimate leg pair. There are no known oviparous species—the overwhelming majority, including all the Neotropical Peripatidae, are viviparous with females that develop a placenta to provide the growing embryo with nutrients. The Asian genera Typhloperipatus and Eoperipatus, however, exhibit lecithotrophic ovoviviparity; that is, their females do not develop any placenta and instead retain yolky eggs in their uteri to supply nourishment.
Distribution and habitat The Peripatidae, also known as equatorial velvet worms, are restricted to the tropical and subtropical zones; in particular, they inhabit Central America, the Caribbean, northern South America, Gabon, Northeast India, and Southeast Asia.
Classification Phylogeny Below is a combined genus-level phylogeny of both extant and extinct peripatid velvet worms.
Neopatida Neopatida is a monophyletic lineage within the Peripatidae, comprising all peripatids except the few found outside of the Americas. As seen above, many genera in Neopatida are paraphyletic or even polyphyletic.
Genera The family consists of the following genera: Cerradopatus Oliveira et al., 2015 † Cretoperipatus Engel & Grimaldi, 2002 Eoperipatus Evans, 1901 Epiperipatus Clark, 1913 Heteroperipatus Zilch, 1954 Macroperipatus Clark, 1913 Mesoperipatus Evans, 1901 Mongeperipatus Barquero-González et al., 2020 Oroperipatus Cockerell, 1908 Peripatus Guilding, 1826 Plicatoperipatus Clark, 1913 Principapillatus Oliveira et al., 2013 Speleoperipatus Peck, 1975 Typhloperipatus Kemp, 1913
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