''Arrup'' is a

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 ...

of soil centipedes in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Mecistocephalidae Mecistocephalidae is a monophyletic family of centipedes in the order Geophilomorpha. It is the only family in the suborder Placodesmata. Most species in this family live in tropical or subtropical regions, but some occur in temperate regions. T ...

. This genus contains sixteen

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), ...

. These

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 ...

are found mainly in

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

regions of

East Asia East Asia is a geocultural region of Asia. It includes China, Japan, Mongolia, North Korea, South Korea, and Taiwan, plus two special administrative regions of China, Hong Kong and Macau. The economies of Economy of China, China, Economy of Ja ...

with some species found in

Central Asia Central Asia is a region of Asia consisting of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. The countries as a group are also colloquially referred to as the "-stans" as all have names ending with the Persian language, Pers ...

and

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. Most species in this genus are soil-dwellers, but the Japanese species '' Arrup akiyoshiensis'' was discovered in a cave and might be a troglobiont.

Description

Centipedes in this genus range from 1 cm to 5 cm in length. All species in this genus have 41 leg-bearing segments. The body is homogeneous in pigmentation, without darker patches. The head in this genus features a transverse suture on the front of the dorsal surface. The side pieces of the labrum are fully divided into anterior and posterior

sclerites A sclerite (Greek , ', meaning " hard") is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instead it refers most commonly ...

. The clypeus in this genus is almost completely areolate and features a longitudinal areolate stripe down the middle. The pleurites on the side of the head lack

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 ...

. 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 ...

is not divided down the middle by a longitudinal suture, and the coxosternite of the second maxillae is also undivided. The telopodites of the second maxillae are too short to reach beyond the first maxillae. The forcipular

tergum A ''tergum'' (Latin for "the back"; : ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton wi ...

is wider than long, with no longitudinal groove down the middle. The first article of the

forcipule Forcipules are the modified, pincer-like, front legs of centipedes that are used to inject venom into prey. They are the only known examples of front legs acting as venom injectors. Nomenclature Forcipules go by a variety of names in both sci ...

features one distal tooth, and the ultimate article features one basal tooth. The groove on the ventral surface of the trunk segments is not forked. The ultimate legs of the male are as slender as those of the female.

Phylogeny

cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

analysis of the family Mecistocephalidae using morphological features places the genus ''Arrup'' in the subfamily Arrupinae, along with the genera ''

Agnostrup ''Agnostrup'' is a genus of soil centipedes in the family Mecistocephalidae. This genus contains three species. These centipedes are found in temperate regions of East Asia. Taxonomy This genus was first described in 2003 by the biologists Do ...

'', ''

Nannarrup ''Nannarrup'' is a genus of soil centipedes in the family Mecistocephalidae. This genus contains only three species, including the type species '' Nannarrup hoffmani''. Also known as Hoffman's dwarf centipede, ''N. hoffmani'' was discovered in ...

'', and '' Partygarrupius''. Further cladistic analysis of the subfamily Arrupinae based on external morphology places the genus ''Arrup'' in a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

with ''Nannarrup'' as a closely related

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

. This analysis also places this clade inside another clade with ''Agnostrup'' as a sister group in the same branch of a

phylogenetic tree A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In ...

. The genus ''Arrup'' shares some distinctive features with its close relatives in the genus ''Nannarrup''. For example, in both genera, the setae on the clypeus are arranged in two groups, one on each side of the clypeus. Furthermore, like all ''Arrup'' species, all ''Nannarrup'' species have 41 pairs of legs. Other features, however, distinguish ''Arrup'' from ''Nannarrup''. For example, the coxosternite of the first maxillae is divided in ''Nannarrup'' but undivided in ''Arrup''.

Species

This genus currently includes sixteen accepted species: *'' Arrup akiyoshiensis'' Tsukamoto & Shimano, 2019 *''

Arrup areolatus ''Arrup'' is a genus of soil centipedes in the family Mecistocephalidae. This genus contains sixteen species. These centipedes are found mainly in temperate regions of East Asia with some species found in Central Asia and California. Most specie ...

'' (Shinohara, 1957) *''

Arrup asiaticus ''Arrup'' is a genus of soil centipedes in the family Mecistocephalidae. This genus contains sixteen species. These centipedes are found mainly in temperate regions of East Asia with some species found in Central Asia and California. Most specie ...

'' (Titova, 1975) *''

Arrup dentatus ''Arrup'' is a genus of Geophilomorpha, soil centipedes in the Family (biology), family Mecistocephalidae. This genus contains sixteen species. These Centipede, centipedes are found mainly in Temperate climate, temperate regions of East Asia with ...

'' (Takakuwa, 1934) *'' Arrup doii'' (Takakuwa, 1940) *'' Arrup edentulus'' (Attems, 1904) *'' Arrup holstii'' (Pocock, 1895) *'' Arrup ishiianus'' Uliana, Bonato & Minelli, 2007 *'' Arrup kyushuensis'' Uliana, Bonato & Minelli, 2007 *'' Arrup lilliputianus'' Uliana, Bonato & Minelli, 2007 *'' Arrup longicalix'' Uliana, Bonato & Minelli, 2007 *''

Arrup mamaevi ''Arrup'' is a genus of soil centipedes in the family Mecistocephalidae. This genus contains sixteen species. These centipedes are found mainly in temperate regions of East Asia with some species found in Central Asia and California. Most specie ...

'' (Titova, 1975) *''

Arrup obtusus ''Arrup'' is a genus of soil centipedes in the family Mecistocephalidae. This genus contains sixteen species. These centipedes are found mainly in temperate regions of East Asia with some species found in Central Asia and California. Most specie ...

'' (Takakuwa, 1934) *'' Arrup pauroporus'' (Takakuwa, 1936) *'' Arrup pylorus'' Chamberlin, 1912 *'' Arrup sauteri'' (Silvestri, 1919)

References

{{Taxonbar, from=Q6507162 Geophilomorpha Arthropods of Asia Taxa named by Ralph Vary Chamberlin