# Schendylops oligopus

Schendylops oligopus is a species of soil centipede in the family Schendylidae. This species is notable as one of only two species in the order Geophilomorpha known to include centipedes with only 27 pairs of legs, the minimum number recorded in this order. Furthermore, S. oligopus was the first species in this order found to feature so few legs.

## Discovery

This species was first described in 1995 by the biologists Luis Alberto Pereira, Alessandro Minelli, and Francesco Barbieri. The original description of this species is based on a large sample, including a female holotype, a male allotype, nine paratypes (eight females and one male), and fourteen other specimens (thirteen females and one male). All specimens were collected in 1982 or 1983 from the Adolfo Ducke Forest Reserve in Amazonas state in Brazil. Pereira and his coauthors named the species oligopus in light of the small number of legs observed in these specimens: All the females had only 31 pairs of legs, and all three male specimens had only 29 pairs, the minimum number recorded at the time in the order Geophilomorpha and a number then shared by only two other species of centipede.
In 2000, Minelli, Pereira, Donatella Foddai, and John G.E. Lewis reported the collection of eleven more specimens (six males and five females) of S. oligopus in 1990. These specimens had the expected number of legs, except for one unusual male with only 27 leg pairs, the first specimen in the order Geophilomorpha recorded with so few legs. S. oligopus remained the only species in this order known to feature so few legs until the discovery of S. ramirezi, another species in the same genus, first described in 2013, with 27 leg pairs in males and 29 pairs in females.

## Taxonomy

Pereira, Minelli, and Barbieri originally described S. oligopus in 1995 under the name Schendylurus oligopus. In 1997, the American zoologist Richard L. Hoffman and Pereira moved this species to the genus Schendylops when they deemed Schendylurus to be a junior synonym for Schendylops.

## Description

All females of this species have 31 pairs of legs, and males usually have 29 leg pairs. In a large sample of 29 males, 35 females, and 13 juveniles of unknown sex, only one male was found to have 27 leg pairs. Females can reach 10 mm in length, and males can reach 8 mm in length. The holotype (preserved in alcohol) is a pale yellowish color.
The species S. oligopus shares a distinctive set of traits with several other species of Schendylops, including S. ramirezi. These features include pore-fields limited to the anterior region of the body, but without a pore-field on the sternite of the first leg-bearing segment. Moreover, the fourth segment of the antenna is similar in length to the contiguous segments.
Although S. oligopus and S. ramirezi share many features, including a similar number of legs, these two species also differ from one another in numerous respects. For example, S. ramirezi features setae on the coxosternite of the first maxillae and a large seta in the middle of the coxosternite of the second maxillae, whereas all these setae are absent in S. oligopus. Furthermore, while both species are notable for their small sizes, S. oligopus is nevertheless larger than S. ramirezi: Females of the species S. ramirezi reach only 7 mm in length, and males reach only 6 mm in length.

## Distribution

This species has been found in four locations in Amazonas state in Brazil, including the type locality in the Adolfo Ducke Forest Reserve.