''Schendylops oligopus'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of soil centipede in the family

Schendylidae Schendylidae is a family of Geophilomorpha, soil centipedes in the superfamily Himantarioidea and the order Geophilomorpha. These centipedes are found in the Americas, the Palearctic realm, Palearctic region, Africa, Madagascar, Australia, and ...

. This species is notable as one of only two species in the order

Geophilomorpha Geophilomorpha is an order of centipedes commonly known as soil centipedes. The name "Geophilomorpha" is from Ancient Greek roots meaning "formed to love the earth." This group is the most diverse centipede order, with 230 genera. These centiped ...

known to include

centipedes Centipedes (from Neo-Latin , "hundred", and Latin language, Latin , "foot") are predatory arthropods belonging to the class Chilopoda (Ancient Greek , ''kheilos'', "lip", and Neo-Latin suffix , "foot", describing the forcipules) of the subphyl ...

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 A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual cell, a multicellular organism, or a community of interacting populations. They usually specialize in ...

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 holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

, 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 Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. 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 Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

Richard L. Hoffman and Pereira moved this species to the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Schendylops ''Schendylops'' is the largest genus of centipedes in the family Schendylidae, containing more than 60 species. This genus was first proposed by the American biologist Orator F. Cook in 1899 for the type species originally named ''Schendyla gran ...

'' when they deemed ''Schendylurus'' to be a

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

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 The sternum (: sterna) is the ventral portion of a segment of an arthropod thorax or abdomen. In insects, the sterna are usually single, large sclerites, and external. However, they can sometimes be divided in two or more, in which case the su ...

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 In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae ...

on the coxosternite of the first

maxillae In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxillar ...

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.

References

{{Taxonbar, from=Q4353177 Schendylidae Endemic arthropods of Brazil